EPA-R2-73-156
JANUARY 1973          Environmental Protection Technology Series
Development and
Preliminary  Design  of a
Sorbent-Oil Recovery System
                      .*«eo sr4^
                               Office of Research and Monitoring

                               U.S. Environmental Protection Agency
                               Washington, D.C. 20460

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            RESEARCH REPORTING SERIES
Research reports of the  Office  of  Research  and
Monitoring,  Environmental Protection Agency, have
been grouped into five series.  These  five  broad
categories  were established to facilitate further
development  and  application   of   environmental
technology.   Elimination  of traditional grouping
was  consciously  planned  to  foster   technology
transfer   and  a  maximum  interface  in  related
fields.  The five series are:

   1.  Environmental Health Effects Research
   2.  Environmental Protection Technology
   3.  Ecological Research
   <*.  Environmental Monitoring
   5.  Socioeconomic Environmental Studies

This report has been assigned to the ENVIRONMENTAL
PROTECTION   TECHNOLOGY   series.    This   series
describes   research   performed  to  develop  and
demonstrate   instrumentation,    equipment    and
methodology  to  repair  or  prevent environmental
degradation from point and  non-point  sources  of
pollution.  This work provides the new or improved
technology  required for the control and treatment
of pollution sources to meet environmental quality
standards.

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                                                       EPA-R2-73-156
                                                       January 1973
         DEVELOPMENT AND PRELIMINARY DESIGN

          OF A SORBENT-OIL RECOVERY SYSTEM
                          By

                       E. Miller
                      L. Stephens
                      J. Ricklis
                Contract No. 68-01-0066
                   Project 15080 HEV


                    Project Officer

                     Kurt Jakobson
        Applied Science and Technology Branch
           Environmental Protection  Agency
                Washington, D.C. 20460


                     Prepared for

          OFFICE OF RESEARCH AND MONITORING
        U.S. ENVIRONMENTAL PROTECTION AGENCY
                WASHINGTON, D.C. 20460
For sale by the Superintendent of Doct^ff|,|^M .SoVernment Printing Office, Washington, D.C. 20402

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              EPA Review Notice

This report has been reviewed by the Office of
Research and Monitoring, EPA, and approved for
publication.  Approval;; does1 not signify that the
contents necessarily reflect the views and policies
of the Environmental, Protection Agency., nor does
mention of trade names or commercial products con-
stitute endorsement or recommendation for use.
                      11

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                          ABSTRACT

A development program was completed and preliminary designs
were prepared for 3000 gallon/hour protected water and
10,000 gallon/hour unprotected water Sorbent Oil Recovery
Systems.  The five phases in the development program were:
(l)  the characterization of the sorbent material., (2) the
development of the sorbent broadcasting system,, (3) the de-
velopment of the- harvesting conveyor and evaluation of over-
all recovery performance, (4) the. development of the sorbent
regeneration system and  (5) model tests of a 1/4-scale model
recovery platform.  The development program showed that a
continuous, sorbent-oil recovery system is feasible using 30
or 80 PPI polyurethane sorbent chips.  In. one pass about
90 percent of the oil in a 1.5 mm slick can be recovered.
The water content of the recovered fluid is less than 10
percent.  The preliminary designs are presented with detailed
descriptions of the system components,, opera'ting procedures,
and costs.

This report was submitted in fulfillment of Project Number
15080 HEV and Contract Number 68-01-0066 under the Sponsor-
ship of the Office of- Research and Monitoring, Environmental
Protection Agency.
                              ill

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                          CONTENTS
Section                                                Page
  I   CONCLUSIONS	   1
 II   RECOMMENDATIONS	   3
III   INTRODUCTION	   5
 IV   DEVELOPMENT PROGRAM	   9
         CHARACTERIZATION OP THE SORBENT MATERIAL	   9
                   4
         DEVELOPMENT OF THE SORBENT BROADCASTING
         SYSTEM	  13
         DEVELOPMENT OF THE HARVESTING CONVEYOR AND
         OVERALL OIL RECOVERY PERFORMANCE	  17
         DEVELOPMENT OF THE SORBENT REGENERATION
         SYSTEM	  22
         MODEL TESTS OF A 1/4-SCALE MODEL RECOVERY
         PLATFORM	  26
  V   SORBENT-OIL RECOVERY SYSTEM DESIGN	  29
         SYSTEM DESIGN PARAMETERS	  29
         PLATFORM CONCEPT SELECTION	  31
         CALCULATION OF SYSTEM CHARACTERISTICS	  33
 VI   3000 GALLON PER HOUR RECOVERY SYSTEM PRELIMINARY
      DESIGN	  37
         GENERAL DESCRIPTION	  39
         RECOVERY SYSTEM COMPONENTS	  39
         RECOVERY PLATFORM	  48
         WEIGHT SUMMARY	  57
         CREW AND OPERATING PROCEDURES	  62
         COST ANALYSIS	  64
                              v

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Section                                                 Page
 VII    10,000 GALLON PER HOUR RECOVERY SYSTEM
        PRELIMINARY DESIGN	   ?1
           GENERAL DESCRIPTION	   73
           RECOVERY SYSTEM COMPONENTS	   76
           RECOVERY PLATFORM	   80
           CREW AND OPERATING PROCEDURES	   91
           COST ANALYSIS	   91
VIII    ACKNOWLEDGMENTS	   97
  IX    REFERENCES	   99
   X    APPENDICES	 !0l
                              vi

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                           FIGURES

                                                        Page

 1     Effect  of Viscosity and  Residence  Time  on  Oil
      Absorption for 30 PPI Polyurethane Foam	   11

 2     Effect  of Viscosity and  Residence  Time  on  Oil
      Absorption for 80 PPI Polyurethane Foam	   12

 3     Full-Scale Sorbent Broadcast  Experiment	   14

 4     The Movable Parallel Plate Nozzle  and the
      Broadcast Pattern Produced by it	   j6

 5     Harvesting Conveyor Test Setup	   19

 6     Sorbent Chip Distribution Carriage	   20

 7     Harvesting Conveyor Operating in Waves	   21

 8     Sorbent Regenerator Test Apparatus	   24

 9     Overall View of 1/4-Scale Model Sorbent Recovery
      Platform	   27

10     Protected Water (3000 GPH) Recovery System
      Arrangement Drawing	   4l

11     Sorbent Regenerator Arrangement Drawing for
      3000 GPH System	.. .   46

12     Diagram of Fan and Pump  Mechanical Transmission
      for 3000 GPH System	   49

13     Schematic Diagram of Fan and  Pump  Hydraulic
      Transmission for 3000 GPH System	   50

14     Schematic Diagram of Sorbent  Regenerator and
      Conveyor Hydraulic Transmission for 3000 GPH
      System	   51

15     Internal Arrangement of  Platform Hulls	   53

16     Midship Section for Aluminum  Construction	   55
                              vii

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                                                        Page

17    Speed Power Curves for Protected Water Oil
      Recovery Unit	   56

18    Unprotected Water Recovery (10,000 GPH) System
      Arrangement Drawing	   75

19   ' Diagram of Fan and Pump Mechanical Transmission
      for 10, 000 GPH System	  8l

20    Schematic Diagram of Fan and  Pump Hydraulic
      Transmission for 10, 000 GPH System	   82

21    Schematic Diagram of Sorbent  Regenerator and
      Conveyor Hydraulic Transmission for 10,000 GPH
      System	   83

22    Viscosities of Oils as a Function of
      Temperature	  105

23    Specific Gravities of Oils as a Function of
      Temperature	  106

24    Effect of Viscosity and Residence Time on Oil
      Absorption	  j 07

25    Effect of Viscosity and Residence Time on Oil
      Absorption	  108

26    Effect of Viscosity and Residence Time on Oil
      Absorption	  109

27    Effect of Viscosity and Residence Time on Oil
      Absorption	  HO

28    Effect of Viscosity and Residence Time on Oil
      Absorption	  HI

29    Effect of Viscosity and Residence Time on Oil
      Absorption	  112

30    Effect of Viscosity on Oil Absorption	  113

31    Chip Broadcast Pattern Achieved in Early Test....  119
                              viii

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                                                       Page

32    Simulated Debris Rake, Flotation . Pods, and
      Side Screens Erected at Discharge End of
      Broadcast Experiment ..............................  122

33    Chip Distributions Obtained with Passive
      External Plate Device .............................  123

34    Chip Distributions Obtained .with Mechanical
      Nozzle ............................................  124

35    Typical Effect of Strong Winds on Chip Dis-
      tribution Patterns ................................  126

36    The Blower Wheel Design Capable of Handling
      Sorbent Chips .....................................  133

37    Experimental ''Friction Coefficient" for Head
      Loss Due to Chips Flowing in Duct .................  137

38    Experimentally Determined Factors Which Account
      for the Effect of Chips on Blower Head and
      Power ............ .................................  139

39    Model of Head and Power Interactions Between
      Blower, Duct, and Chips ...........................  l4l
40    Harvesting Conveyor Performance ...................

4l    Oil Recovery versus Viscosity - (Calm Water)......  148

42    Percent Oil in Recovered Fluid versus Viscosity
      (Calm Water) ................ . .....................  149

43    Oil, Recovery versus Viscosity (Waves ) .............  150

44    Percent Oil in Recovered Fluid versus Viscosity
      (Waves ) .......... . ................................  151

45    Oil Recovery versus Residence Time  (Calm' Water )...  153

46    Oil Recovery versus Residence Time  (Waves) ........  154

47    Oil Recovery versus Nominal Sorbent Coverage ......  156
                              ix

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                                                        Page
                                                        _

48    Sorbent Oil Recovery Performance in Waves ........   157

49    Water Recovered by Sorbent versus Slick
      Viscosity ................. >••<•••, ...... ...........
50    Water Entrainment Rate Due to Conveyor versus
      Conveyor Speed ......................... _ ..........   J-59

51    Sorbent Regenerator Test Apparatus ...............   162

52    Sorbent Regenerator Test Apparatus  Setup... ......   163

53    Regenerated Sorbent Density versus  Squeezing
      Force (80 PPI Foam) No.  2 Heating Oil ............   165

54    Regenerated Sorbent Density versus  Squeezing
      Force (80 PPI Foam) 011-70 Percent  Bunker "C"
      30 Percent No. 2 .................................   166

55    Regenerated Sorbent Density versus  Squeezing
      Force (30 PPI Foam) Bunker "C" ...................   167

56    Regenerated Sorbent Density versus  Viscosity .....   169

57    Sorbent Chips After Endurance Test ...............   171

58    Oil Sorbent Recovery System;  Pontoon Assembly. . . .   174

59    Mechanical Details of Sorbent Recovery
      Platform Model ...................................   176

60    Test Setup for Sorbent Recovery Platform Model...   178

6l    Sorbent Recovery Platform Deployment Draft -
      Towline Drag versus Speed and Sea State ..........   180

62    Sorbent Recovery Platform Deployment Draft -
      Towline Drag versus Speed ........................   181

63    Sorbent Recovery Platform Under Tow at 9-5
      Knots ............................................   182

64    Sorbent Recovery Platform Operating Draft -
      Towline Drag versus Speed and Sea State ..........   183
                              x

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                                                        Page

65    Sorbent Recovery Platform Drag Coefficient
      versus Speed-Length Ratio	   18JI

66    Recovery Platform Operating in Calm Water at
      3.0 ft/sec	   186

67    Recovery Platform Operating in Sea  State 1  at
      3 ft/sec	   18?

68    Recovery Platform Operating in Sea  State 3  at
      3 ft/sec	   188

69    Sorbent Recovery Platform Relative  Motion in
      Regular Waves	   190
                              xi

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                           TABLES
 1    Range of Parameters in Sorbent Material
      Characterization Tests. .*.... j	   10

 2    Typical Limiting Parameters on a Sorbent-Oil
      Recovery System. ...... . .......	   30

 3    Desirable Recovery System Platform
      Characteristics. \ .... L .	   31

 4    Advantages of Specifically Designed Recovery
      Platform. ...... i . k ,....;.......	   32

 5    Advantages of a  Vessel of Opportunity as  a
      Recovery Platform.. i. i ......	   32

 6    Specific Design  Goals  for Protected Water
      System. .'	»	   37

 7    Characteristics  of Protected Water Sorbent-Oil
      Recovery System* . . . . . . . . ;	   40

 8    Broadcasting System Characteristics	   42

 9    Harvesting Conveyor Characteristics	   43

10    Transfer Conveyor Characteristics	   44

11    Sorbent Regenerator Characteristics	   45

12    Platform Characteristics . . . i i i .	   52

13    Outfit Items	i * » . , i .- i t . i-. . . :	   57

14    Weight Estimate  for 3000  GPH Protected Water
      Sorbent-Oil Recovery System. \ ; . .-	
15    Duties of Recovery System Crew*
16    3000 GPH Protected Water Recovery System Cost
      Analysis ..........^	
                              xiii

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17    3000 GPH Protected Water Recovery System Total
      Construction Costs	    '

18    Detailed Analysis of Protected Water Unit Re-
      covery Machinery Cost	• •  ""

19    3000 GPH Protected Water Recovery System Direct
      Operating Costs	  °9
20    Specific Design Goals for Unprotected Water
      System

21    Characteristics of Unprotected Water Sorbent
      Oil Recovery System
22    Broadcasting System Characteristics .............

23    Harvesting Conveyor Characteristics .............  77

21!    Transfer Conveyor Characteristics ...............  78

25    Sorbent Regenerator Characteristics .............  79

26    Unprotected Water System Platform
      Characteristics .................................  84

27    Unprotected Water System Outfit Items ...........  85

28    Weight Estimate for Unprotected Water Sorbent-
      Oil Recovery System .............................  86

29    Unprotected Water Recovery System Cost
      Analysis ........................................  0,2

30    Unprotected Water Recovery System Total Con-
      struction Costs ............................       no

31    Unprotected Water Recovery Unit Recovery
      Machinery Cost                                    nj.
32    Unprotected Water Recovery System Direct Op-
      erating Costs
33    Oil Absorption Fluxes
                            xiv

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                                                       Page

34    Sorbent Chip Loss Rates Experienced in Pull
      Scale .Model Tests	   127

35    Types of System .Loss.es.	  .131

36    Viscosity of Test Oil  Products	•	  -168
                               xv

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                          SECTION I

                         CONCLUSIONS

1.    Continuous sorbent oil recovery systems are practical
     and can be designed to recover a wide range of oil
     products.

2.    Systems designed for recovery rates of 3000 GPH in pro-
     tected waters and 10,000 GPH in unprotected waters will
     basically satisfy the general and specific design goals
     given by the EPA.

3.    Sorbent oil recovery systems can recover about 90 per-
     cent of the oil from a slick in a single pass.   This
     performance can be achieved over a wide range oil
     viscosities,, slick thickness and wave heights.

4.    Water in the recovered fluid will be about 10 percent
     for typical operating conditions.

5.    Depending on the options selected and the number pro-
     duced,, the initial cost of a 3000 GPH protected water
     recovery system will range between $40,000 and $80,000.
     For a 10,000 GPH unprotected water recovery system the
     cost will range between $55,000. and $105,000.   Op-
     erating costs for the 3000 GPH system will be between
     $100/hour and $200/hour and for the 10,000 GPH system
     between $400/hour and $600/hour.

6.    Based on the results of the development program,
     rational design procedures have been formulated for
     the selection of system and sub-system characteristics
     and hardware.

7.    The sorbent material used in the recovery system should
     be open cell reticulated polyurethane foam cut into
     chips approximately 3 in. x 3 in. X 1/4 in.  80 PPI
     foam should be used for oils with viscosities less
     than 1000 cps and 30 PPI foam should be used for vis-
     cosities greater than 1000 cps.

8.    A pneumatic sorbent broadcasting system using a fan
     with a long shavings type wheel and a moving parallel
     plate distribution nozzle will provide satisfactory
     sorbent distribution patterns and conveying performance,

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 9.   The recovery platform must .provide a  sheltered location
     for sorbent broadcasting  to  reduce losses  in winds.   If
     this is done the sorbent  lost  rate will  be small under
     normal operating conditions  and  will  not exceed 2 per-
     cent of the broadcast rate in  winds of 30  mph.

10.   The recovery platform should have  a catamaran configura-
     tion because it  provides  a sheltered  location for broad-
     casting the sorbent,  a means of  herding  the sorbent  to
     the harvesting conveyor and  a  location for mounting  the
     harvesting conveyor.

11.   In order to achieve high  recovery  efficiency the sorbent
     material should  remain in contact  with the slick for
     periods of 15 to 30 seconds.

12.   The harvesting conveyor should be  at  an  angle of 4-5
     degrees and run  with a linear  belt speed equal to the
     sweep speed.

13.   A converging belt type sorbent regenerator can regenerate
     sorbent material at a loading  of .30  ft3/ft2  and a belt
     speed of 1.0 ft/sec.   A squeezing  force  of about 200
     Ib/in. of belt width is required.   The density of the
     regenerated sorbent after squeezing will be about 6.0
     lb/ft3 which is  satisfactory for pneumatic broadcasting.

14.   The sorbent material can  be  regenerated  with oil vis-
     cosities up to 20,000 cps at the time of squeezing.
     Heating coils will be required to  reduce the oil vis-
     cosity to about  1000 cps  for satisfactory  flow in the
     oil collection pans.

15.   The sorbent material can  be  regenerated  in excess of
     100 times without deterioration.
16.   Model tests  conducted  at  1/4  full,  scale  for  the  10,000
     GPH system demonstrated that  a  continuous, stable,
     sorbent broadcasting and  recovery  cycle  is possible
     and that it  is  not  sensitive  to waves  and sweep  speed.
                              2

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                        SECTION II

                      RECOMMENDATIONS

The development program and design studies carried out in
this project indicate that a continuous sorbent oil recovery
system is feasible and practical.   In order to advance such
systems to field applications it is necessary to design..
build and test a prototype system.  It is recommended that
such a prototype program be undertaken.  Because of its more
general application and lower cost, the 3000 GPH protected
water unit would be a suitable candidate for such a program,

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                        SECTION III

                       INTRODUCTION

In the event of an oil spill it is desirable from the stand-
point of the total environment to physically remove the oil
from the water.  There are several.basic methods which can
be employed for physical removal of the oil.  These are:
direct skimming•by means of a special skimming device; the
use of pumps in conjunction with oil-water separation equip-
ment; or oil collection with a sorbent material followed by
mechanical removal of the sorbent material.   The sorbent-
material method has the advantages that the sorption process
is not affected by waves or current and that a high percentage
of oil in the recovered fluid can be obtained.  As a result,
large volumes of sorbent material have been used in oil spill
clean up operations.  However, this method has disadvantages
such as the generation of a large volume o-f waste material
which requires  controlled disposal and the lack of mechanical
systems to recover the sorbent material.  Thus., the use of
sorbent materials for oil recovery has been an effective but
expensive procedure.

In an effort to overcome the disadvantages associated with
the use of sorbent material, the U. S. Environmental Pro-
tection Agency  issued a RFP for the development of Sorbent
Oil Recovery Systems in late 1970.  HYDRQNAUTICS, Incorporated
was awarded one of five research contracts in June of 1971
for the development of a sorbent oil recovery system based
on the use of a synthetic foam sorbent material which could
be recycled many times.  This report presents the results of
this development effort.-

In order to guide the developmental phase, the Environmental
Protection Agency provided the following general design goals
for an oil recovery system using sorbent materials.

                   GENERAL DESIGN GOALS

1.   Rapid oil recovery rate.

2.   Complete removal of oil from the water surface.

3.   Minimum amounts of water entering each unit process.

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 4.   Minimum influence of water motion and waves on collec-
     tion efficiency.

 5.   Minimum amount of auxiliary equipment.

 6.   Reject floating solids of a size which will interfere
     with the efficiency of,  or damage,  the recovery system.

 7.   High mobility and maneuverability.

 8.   Compatibility with marine life.

 9.   Reasonable first cost.

10.   Low operating expense.

11.   Minimum maintenance requirements.

12.   Maximum ease and speed of repairs.

13.   Readily available replacement parts.

14.   System'independent of physical properties of oil.

15.   Readily available sorption material.

16.   Sorption material easily transportable to location
     of spill.

I?.   Sorption material must be compatible  with land harvest
     methods.

18.   Sorption material must not increase flammability of
     oil.

In addition, specific design goals were provided for a pro-
tected water system capable of recovering  3000 gallons/hour
from a 1.. 5 mm, thick slick and an unprotected water system
capable of recovering 10,000 gallons/hour  from a 1.5 mm
slick.  These'specific design goals are outlined in the sub-
sequent sections of this report along with preliminary de-
signs for these two systems.

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In the development of a sorbent oil recovery system it is
desirable to consider the basic unit operations involved.
These basic unit operations are:

            1.  Sorbent Broadcasting
            2.  Oil-Sorbent Harvesting
            3.  Oil-Sorbent Separation
            ]4.  Vessel or Platform Configuration
            5-  Oil Storage or Disposal
            6.  Sorbent Reuse or Disposal

Based on these unit operations., a development program was
formulated and carried out which included five experimental
tasks and a preliminary design task.  The five experimental
tasks were:

            1.  Characterization of the Sorbent Material

            2.  Development of the Sorbent Broadcasting
                System
            3.  Development of the Harvesting Conveyor and
                Evaluation of Overall Oil Recovery Per-
                formance

            4.  Development of the Oil Sorbent Separation
                System, and

            5.  Model tests of a 1/4-scale Recovery Platform
                to determine system stability and operation
                in waves.

The preliminary design task included the formulation of de-
sign procedures and criteria based on the five experimental
tasks and the preparation of preliminary designs for the
3000 and 10,000 gallon/hour recovery systems.

The complete results of the sorbent oil recovery system de-
velopment program are presented in this report..  Section IV
presents a brief description of each of the five experimental
tasks in the development program; the details and the data
from each of these tasks are presented in the appendices.
Section V presents a summary of the design methods, criteria
and observations which resulted from the development program.
Sections VI and VII present  descriptions and technical de-
tails from the preliminary designs of the 3000 and 10,000
gallons per hour recovery systems, respectively.

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                        SECTION IV

                    DEVELOPMENT PROGRAM

Five experimental tasks were carried out in support of the
development of an Oil-Sorbent Recovery System.  These five
tasks are briefly described in this section and additional
details are presented in the appendices.

CHARACTERIZATION OP THE SORBENT MATERIAL

The objective of this task was to develop data on the oil
absorption capabilities of the sorbent material as a function
of sorbent characteristics, oil characteristics, slick thick-
ness and residence time on the slick.  The sorbent material
selected for use in the oil-sorbent recovery system was an
open-cell reticulated polyurethane foam made by the Scott
Paper Company.  This material was selected during the pro-
posal stage of this project and was based on previous work
carried out by HYDRONAUTICS, Incorporated using sorbent ma-
terials.  This work is reported in Reference 1.

The experiments were carried out in a 4 ft by 4 ft plastic
tank 10 in. deep.  This tank was equipped with a temperature
control system, temperature measuring devices, and a microm-
eter for measuring oil slick thickness.  Tests were conducted
by establishing a slick of known characteristics and
thickness on the water surface.  A chip of sorbent material
of known weight was dropped on the slick and allowed to sit
for a given time.  The chip was then picked up, allowed to
drain for 10 seconds and reweighed to determine the amount
of oil picked up.  This process was carried out with several
chips and an average value was taken for the amount of oil
absorbed.  The range of parameters covered in the tests are
given in Table 1.

In a system in which the sorbent material is reused, the im-
portant thing is not to maximize the quantity of oil absorbed
per unit volume of sorbent, but rather to maximize the total
rate of oil absorption.  As a result, a high percentage of
the slick surface must be covered with sorbent material and
individual sorbent chips will not have the opportunity to
absorb oil to their maximum capacity.  Thus, it is most
meaningful to express the oil absorption performance of the
sorbent as an absorption ratio rather than as either the

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absolute volume of oil absorbed or the maximum volume of oil
that could be absorbed.   The absorption ratio is defined as
the ratio of the amount of oil absorbed to the amount of oil
directly beneath the sorbent chip.   This ratio indicates the
extent to which oil in the slick can flow in the edges of the
chip and the inverse of this ratio indicates the percentage
of the slick which must be covered with sorbent for complete
oil recovery.

                          TABLE 1

          Range of Parameters in Sorbent Material
                  Characterization Tests
        Parameter
Range
  Slick Thickness

  Oil Type

  Slick Temperature

  Residence Time of Sorbent
                  on Slick

  Sorbent Porosity


  Sorbent Chip Geometry

  Sorbent Reusability
                     !! rill
0.5 - 3-5 mm
Diesel, No.  4, Crude, Bunker "C
4 - 27°C

0 - 60 sec.  Mostly 5, 10, 15,
                   30 sec.

30,60,80,100,  Mostly 30 and
                      80 PPI
Square and Rectangular
Fresh and Regenerated, Mostly
                Regenerated
Most of the tests were carried out using 3 in.  x 3 in.  x 3/8
in. chips of the sorbent material.  Tests with rectangular
chips did not show significant improvements in the absorption
ratio.   It was believed that rectangular chips might be more
difficult to broadcast so they were not considered further.
Typical test results are presented in Figures 1 and 2 which
show the effects of oil viscosity and residence time on the
absorption ratio.  Both figures apply to slick thicknesses
of 1 to 2 mm.  Figure 1 is for 30 PPI (pores per linear inch)
and Figure 2 is for 80 PPI polyurethane foam.  The test re-
sults for other conditions as well as a more detailed de-
scription of this task are presented in Appendix A.
                             10

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I—
                      280
                      240
                      200
                      160
                  Z
                  O
                  $  120
                  CD
                      100
                       80
                       40
                                                                                   1       T
                                                POLYURETHANE FOAM
                                                POROSITY - 30 ppi
                                                SLICK THICKNESS 1 -2mm
                                                O  5 sec
                                                D  10 sec
                                                O  15 sec
                                                A  30 sec
                                    DIESEL
CRUDE
          BUNKER "C"
                                               10
          100
1000
10,000
                                                                  KINEMATIC VISCOSITY cm /sec
                                             FIGURE  1 - EFFECT OF VISCOSITY AND RESIDENCE TIME ON OIL ABSORPTION
                                                       FOR 30 PPI POLYURETHANE FOAM
100,OOC

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                                                            POLYURETHANE FOAM
                                                            POROSITY - SOppi
                                                            SLICK THICKNESS 1 - 2mm
                                                            O 5 sec
                                                            D 10 sec
                                                            O 15 sec
                                                            A 30 sec
                                            1000
                     KINEMATIC VISCOSITY cm /sec
10,000
                                                                                                            OJ
                                                                                      100,000
FIGURE 2  - EFFECT OF VISCOSITY AND RESIDENCE TIME ON OIL ABSORPTION
           FOR 80 PPI POLYURETHANE FOAM

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The important results from this development task can be
summarized as follows:

     -  The absorption ratio decreases with increasing oil
        viscosity.  For oils such as No. 6 and Bunker "C"
        almost 100 percent coverage of the slick will be
        required.

        The absorption ratio does not increase greatly with
        residence time for viscous oils such as No. 6 and
        Bunker "C".

        30 and 80 PPI foam have equal absorption ratios for
        .Oils with viscosities greater than 50 cps.   For lower
        viscosities.,  the 80 PPI foam is superior because oil
        will not drain out "of it as it .is removed from the
        slick.  Tests were not conducted with viscosities
      .., less than 2 cps.

        Square chips  have as high absorption ratios as
        rectangular chips for the range of slick thickness
        and oil viscosities of interest.

DEVELOPMENT OF THE SORBENT BROADCASTING SYSTEM

The objectives of this task were:

        To develop and demonstrate a means of evenly dis-
        tributing sorbent material chips across the Inner
        width of the  recovery platform at its forward end.

        To develop and demonstrate a pneumatic system for
        conveying chips from the oil removal section of the
        recovery platform to the distribution device.

These objectives were accomplished with developmental model
tests.  Due to the specialized nature of the problem,, the
model size and other  parameters were maintained at near full
scale to reduce scaling uncertainties in the prototype design
stage.  Figure 3 shows an overall view of the experimental
setup.  The test program was directed at the development of
a satisfactory broadcasting nozzle and at the measurement of
the pneumatic conveying system performance.
                             13

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              INTERIOR OF FEEDER BOX
   BASIC NOZZLE WITH TRIAL GUIDE VANES INSTALLED
           OVERALL VIEW OF EXPERIMENT
FIGURE 3 - FULL SCALE SORBENT BROADCAST EXPERIMENT

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For the purpose of the broadcasting experiments,, it was as-
sumed that a 100 percent nominal  coverage of the slick would
be required.  Thus, using 3  in. y 3 in. square  chips, for a
slick thickness of 1.5 mm. a  recovery rate of 3000 GPH would
require broadcasting 21,'iOO  chips/ml mite.  A rate of 10,000
GPH would require a rate of  7^,000 chips/minute.  Initial
design studies indicated that,  for the  10,000 GPH recovery
unit, the sorbent broadcast  pattern would have  to be about
32 ft wide.  It was hoped that  a  single passive nozzle- with
fixed guide  vanes could achieve a uniform distribution with
this width.  However, the tests showed  that, at near the
design chip  rate, a simple nozzle with  fixed vanes would jam
with chips.  To overcome this problem,  a movable parallel
plate nozzle concept was developed.  This nozzle produced
satisfactory distribution patterns at the design chip rate.
Figure j! shows the nozzle installed on  the experimental
setup.  Tests In wind showed some distortion of the broad-
cast pattern and Indicated that the chip loss rate would be
less than 2  percent of the broadcasting rate.

The pneumatic conveying system  performance parameters were
measured during the tests conducted for nozzle  development.
These performance parameters include the air speed necessary
for good conveying, the head loss in the transport duct, the
head, loss across the fan, and the fan power required.  These
parameters were determined as a function of the ratio of the
weight of sorbent material to the weight of air.  During the
tests, it was determined that the sorbent chips could be fed
directly through a centrifugal  blower equipped  with a long
shaving type wheel.  Preliminary  tests  revealed that the
chips should be'stiff enough so that, upon contact with the
wall of the  transport ducts, they would not collapse and
flatten completely against,the  wall.  This implies a thick-
ness of 1/4  in. to 3/8 In. for  the 3 in. by 3 in. chips.

Based on the results of the  test  program, a design procedure
was formulated for estimating the size, air flow rate, fan
characteristics and power of a  pneumatic conveying system.
A more detailed description  of  the sorbent broadcasting
system development program,  including the test  data, the
design procedure and an example problem, is presented in
Appendix B.
                              15

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FIGURE 4 - THE MOVABLE PARALLEL PLATE NOZZLE AND THE
          BROADCAST PATTERN PRODUCED BY IT
                       16

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The important results from this development task can be
summarized as follows:

     -  A sorbent broadcasting system can be designed,  based
        on a pneumatic conveying principle, which will  meet
        the performance requirements and yet be of practical
        size.

     -  A movable parallel plate nozzle concept will produce
        a satisfactory broadcast pattern width and distri-
        bution.

     -  Wind will distort the broadcast pattern somewhat
        but the sorbent loss rate will be less than 2 per-
        cent of the broadcast rate.

        A rational design procedure was. developed for
        selecting components for a pneumatic conveying
        system.
                                            •t
DEVELOPMENT OP THE HARVESTING CONVEYOR AND OVERALL OIL
RECOVERY PERFORMANCE

The objectives of this task were:

        To determine  the conveyor inclination angle and
        speed for optimum performance.

        To uevelop data on system performance as a function
        of the operating parameters, using the optimum  con-
        veyor operating condition.

The system performance was defined both in terms of the
percentage of the oil in a slick which is recovered and the
percentage of oil in  the recovered fluid.  The general  and
specific design goals supplied by the EPA request 100 per-
cent recovery of the  oil from the slick and in excess of
90 percent oil in the recovered fluid.  The operating pa-
rameters which were studied in addition to the conveyor
angle and speed included:

     -  Slick thickness and viscosity (oil type and'
        temperature)
                             17

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        Sorbent coverage

     -  Residence time

        Calm water versus  waves

The objectives of this task were accomplished by means  of
an experimental program.  In order to avoid scaling problems,
the tests were carried out using typical  oil products,  full-
size sorbent chips,  and the actual conveyor belt material.
The tests were conducted in a tank which  is 80 ft long  2 ft
wide and 2 ft deep.   In effect this test  setup was equivalent
to a 2 ft wide strip along the centerline of the recovery
system.  Figure 5 is a photograph of the  harvesting conveyor
setup in the 80-ft tank.  The conveyor material is 1 in.
mesh-opening flat-wire belt.  Figure 6 is a photograph  of
the carriage used to distribute the sorbent chips on the slick
in the tank.  The tests were conducted in accordance with
the following procedure:  First, a slick  of known thickness
was established on the water surface in the tank.   The  sor-
bent material was then distributed on the slick by the  sor-
bent distribution carriage.  After waiting the required
residence time, the harvesting conveyor was run down the
tank collecting the sorbent chips and dropping them in  a
collection box.  Figure 7 shows  a typical test in progress.
After the run, the chips in collection box were regenerated
and the amount of oil and water  measured.  The amount of oil
remaining in the tank was  also measured to determine the
recovery performance or efficiency.

The first part of the test program was directed at deter-
mining the effects of conveyor-belt angle and speed on  per-
formance.  Based on these tests, a conveyor angle of ^5
degrees and belt speed equal to  forward speed were selected
for the remaining tests.  These  tests covered the range of
parameters listed above.  These  data were reduced to pa-
rametric curves showing percent  of oil recovery and percent
oil in the recovered fluid as a  function  of the independent
parameters.  These curves  may be used directly in the design
and performance prediction of sorbent oil recovery systems.
These curves and a more detailed description of this task
are presented in Appendix C.

The important results from this  development task can be
summarized as follows:
                             18

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FIGURE 5 - HARVESTING CONVEYOR TEST SETUP

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FIGURE 6 - SORBENT CHIP DISTRIBUTION CARRIAGE

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FIGURE 7 - HARVESTING CONVEYOR OPERATING IN WAVES
                        21

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     -  A 1 in.  mesh flat-wire belt will be satisfactory
        for the harvesting conveyor.

        The harvesting conveyor should be at an angle of
        45 degrees and run at a belt speed equal to the
        forward speed.

        The oil recovery percentage will range from 90 to
        95 percent over a wide range of oil types and slick
        thicknesses.

     -  The percent oil in the recovered fluid will meet the
        EPA goal of 90 percent for slick thickness of 1.5 mm.

        Waves will improve the oil recovery percentage
        relative to calm water because they agitate the
        sorbent causing it to contact a higher percentage
        of the slick surface.

DEVELOPMENT OF THE SORBENT REGENERATION SYSTEM

The polyurethane foam sorbent material can be regenerated
for reuse simply by mechanically squeezing out the recovered
oil.  The sorbent regeneration system must perform this
squeezing operation on a large enough volume of sorbent ma-
terial to satisfy the required flow rate over the range of
operational requirements.  In effect, the sorbent regenera-
tion system is the key element which makes a continuous cycle
sorbent oil recovery system possible.  The sorbent regenera-
tion system is also the most complex mechanical component
in the system.

The concept of a converging-belt squeezing device was selected
for development as the sorbent regenerator.  In this concept,
the sorbent material is carried between two conveyor belts
through a series of squeezing rollers.  The upper conveyor
belt converges with the lower belt at the entrance to the
first pair of squeezing rollers.  The upper belt is solid
and the lower belt is porous so that the oil squeezed out
flows through it into collecting pans.  This concept was
selected for the following reasons:

        -  A large volume of sorbent can be handled between
           small-diameter squeeze rollers.
                             22

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        -  There is no relative movement between the belts
           and the sorbent which could damage the sorbent.

        -  The squeeze rollers, can be mounted to allow large
           travel between them.  This makes the regenerator
           tolerant of debris and drift wood which can run
           through the machine without causing damage.

        -  The physical dimensions of the resulting machine
           are compatible with the arrangement of the overall
           system.

A development task was carried out based on the converging-
belt regenerator concept.  The objectives of this task were:

           Develop performance data for a converging belt
           sorbent regenerator as a function of the design
           parameters.

           Determine  the effects of repeated cycles on the
           sorbent material.

           Identify and resolve mechanical problems prior
           to the design of a prototype system.

These objectives were carried out by designing, building
and testing a sorbent regenerator test apparatus.  This
test apparatus was about the same size and included many of
the features of a sorbent regenerator for a 3000 GPH re-
covery unit.  Figure  8 presents photographs showing overall
views of the sorbent  regeneration test apparatus and the
system under test.  The test is being carried out with 80
PPI foam and an oil mixture of ?0 percent bunker "C" and
30 percent No. 2.  The recovered oil can be seen flowing
into the barrel.  In  a typical operating condition, the
sorbent regenerator will have to remove about 2 gallons of
oil per cubic foot of sorbent.

The broadcasting process which directly follows regeneration
is sensitive to the density of the sorbent.  Thus the per-
formance of the sorbent regenerator is defined in terms of
the density of regenerated sorbent from which 2 gallons of
oil per cubic foot have been recovered.
                            23

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           Overall View of Test Apparatus
                System Under Test
FIGURE 8 - SORBENT REGENERATOR TEST APPARATUS

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The test program was carried out to determine the influence
of various parameters on the density of the regenerated sor-
bent.  These parameters included:

        -  Squeezing Force

        -  Belt Speed

           Sorbent Loading
           Sorbent Type

        -  Oil Viscosity

The results were plotted as parametric relationships which
allow the selection of squeezing force, belt speed,,  sorbent
loading and sorbent type for a given viscosity and required
density.  These parameters determine the mechanical char-
acteristics of the sorbent regenerator.  In addition,  the
test program covered endurance tests on the sorbent.  Ob-
servations during the testing indicated several mechanical
refinements which should be included on the prototype design.
                             /
Appendix D presents further details with respect to the
sorbent regenerator development, test programs, data,  and
observations.  The important results of this task can be
summarized as follows:

           A converging-belt sorbent regenerator will
           satisfactorily regenerate sorbent chips at the
           volume rates required.

        -  The density of the regenerated chips will be-
           about 6 lb/ft3 for a squeezing force of 220 lb/
           in., a sorbent loading of 0.25 ft3/ft2 and a
           belt speed of 1 ft/sec.

           In order to maintain a 6 lb/ft3 regenerated
           sorbent density, 30 PPI foam should be used for
           oil viscosities in excess of 1000 CPS.

        -  An oil viscosity of about 20,000 CPS at the time of
           regeneration is the practical upper limit because
           of the excessive density of the regenerated sorbent

        -  The sorbent material can be cycled over 100 times
           without significant degradation.

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MODEL TESTS OF A 1/4-SCALE MODEL RECOVERY PLATFORM

The objectives of this task were:
                       "~y.    g.  ,.,   '     •'    '",•"*
    :•"•   ^  To determine,5 whether a-> continuous stable sorbent
            broadcast and.recovery cycle is possible.
             ., ,.            '   '»••!•*  ,,, •'."
             '^/    ^i           i    a
            To'determine if there are any adverse effects of
            wave's">nd forward speed on the continuous broadcast
            and'1 recovery cycle.;  ,'

         -  To determine the towing resistance and stability
            of the recovery platform at the deployment and
            operating draft.
                                                    *
The objectives of this task were satisfied by means of tests
conducted on a 1/4-scale model of a recovery platform concept
in the HYDRONAUTICS Ship Model Basin (HSMB®).  The model was
equipped with an operating broadcasting system and harvesting
conveyor.  No squeezing system was  fitted on the model and
no attempt was made to actually  recovery oil.  The recovery
platform model was based on the  concept presented in the
original HYDRONAUTICS,, Incorporated Sorbent Oil Recovery
System Proposal.   Subsequent preliminary sizing studies in-
dicated that the basic concept and  general proportions were
still valid.  Thus the model was sized to be a 1/4-scale
model of a system intended to recover 10,000 gallons per
hour.   Figure 9 is a photograph  showing the overall arrange-
ment of the model.

Tests were conducted for both towing and pushing the recovery
platform over a  range of speeds  up  to 6 ft/sec full scale and
over a range of  wave heights up  to  a low Sea State 3 full
scale.  Measurements were made of the towing drag, speed,
wave height and  relative motions between the water surface
and the platform.  Observations  and photographs were obtained
of the sorbent distribution and  collection.  The data and
detailed observations obtained from these tests, along with
a more detailed  description of the  model and test procedures,,
are presented in Appendix E.

The important results from this  development task can be
summarized as follows:
                             26

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FIGURE 9 - OVERALL VIEW OF 1/4-SCALE MODEL SORBENT
          RECOVERY PLATFORM


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A continuous sorbent broadcasting and recovery
operation with a uniform stable distribution of
sorbent material can be achieved.

The sorbent broadcasting and recovery operation
will not be degraded by waves up to a low Sea
State 3 and forward speed up to 6 ft/sec.      . ;

The movable parallel plate broadcasting nozzle
concept developed in a previous task provided a
uniform transverse distribution of sorbent
material.

The sorbent material did not show any tendency to
plug the inlet to the harvesting conveyor.

The recovery platform can be towed up to a speed
of 9-5 knots in the deployment condition.

The recovery platform is directionally stable
under tow.
                 28

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                         SECTION V

            SORBENT-OIL RECOVERY SYSTEM DESIGN

Based on the results of the development programs described
in Section IV, design procedures  have  been defined for
sorbent oil recovery systems and the results are presented
in this section.  These design procedures apply to con-
tinuous-cycle sorbent broadcast,, recovery,, regeneration sys-
tems.  In order to minimize the effects of environmental
parameters such as wind and waves it is intended that the
sorbent material remain in unrestrained contact with the
slick long enough to absorb the oil.  The following dis-
cussion does not apply to systems in which the sorbent ma-
terial is intended to form a cake or filter to remove the
oil.

SYSTEM DESIGN PARAMETERS

The independent parameters which determine the character-
istics of a sorbent oil recovery system are:

            Oil characteristics (i.e.,, viscosity)

         -  Slick Thickness

         -  Total Oil Recovery Rate

            Sweep Speed of the Recovery Platform

            Sorbent Residence Time

            Percent of Surface Covered by Sorbent

These parameters can be used to define the basic geometric
parameters of the platform such as sweep width and active
length,, and operating parameters such as sorbent broadcast
rate,, broadcast distances and water recovery rate.  In
general, the  first three parameters listed are specified as
part of the specific design goals for the system; the sys-
tem designer  can select the last three parameters listed.

The percent of the surface covered by sorbent and the
residence time determines the percent of oil recovered from
the slick for given oil characteristics and slick thickness,
The relationship between these parameters is illustrated in
Figure 48 for typical conditions.  With the percent oil
                             29

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recovery,  the total slick area  that must be swept per unit
time to satisfy the total oil recovery rate can be calculated.
The sweep rate (area per unit time) and the percent sorbent
coverage define the sorbent broadcast rate.   The sweep rate
divided by the sweep speed gives  the width of the sweep or
sorbent broadcast pattern.   The product of sweep speed and
residence time gives the active length of the system.    The
active length is defined as the distance between the sorbent
contact point with the slick and  the harvesting conveyor.

The above shows that there are  an infinite number of combina-
tions of sweep speed,  residence time and sorbent coverage
which will satisfy a given set  of specific design goals.   As
a result,  other parameters must be introduced in order to
produce a unique design solution.   These parameters may in-
clude:

             Minimum cost
             Limitations on system or component dimensions

             Practical limits on  the range of the independent
             parameters

             General design goals

In general,  the procedure is to design for minimum cost with-
in the limitations imposed by the other parameters.   Table 2
lists typical limiting parameters except cost.

                           TABLE  2

          Typical Limiting Parameters on a Sorbent-
                     Oil Recovery System
      Dimensions
   Practical
General Design
     Goals
 Limiting component
 length,  width,  height
 and weight for  highway
 or air transport.


 Overall  length,
 width,  height  or
 draft of restricted
 areas (under pi^rs,
 between  ships).
Residence times in
excess of 30 sec-
onds do not im-
prove recovery
percentage.

Sorbent coverage
in excess, of 90
percent does not
improve recovery
percentage.
Maximum practi-
cal oil recovery
percentage.
Others as listed
in the Intro-
duction.
                              30

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In each case, the system designer must identify which of
these limiting parameters apply and assign them a weight.
Ideally the cost that should be minimized is the total life-
cycle cost per gallon recovered discounted to" present''value.
In practice, this is not possible since the operating sce-
nario, the social discount rate, and the social value of a
gallon  of recovered, oil are -not known.  As >a 'pesult,, the^-
simplified procedure of-minimizing the sum of the-'capital'* •
and operating cost based on an assumed operating cycle has
been adopted.                                      .  .

PLATFORM CONCEPT SELECTION

In the design of a sorbent-oil recovery system, a decision'
must be made as to whether to mount the system' on a vessel
of opportunity or on a specifically designed vessel- "or plat-
form.  In either case, the platform characteristics, must be
suitable for the recovery system equipment.  Some -of- the"
desirable characteristics of a sorbent-oil recover-y s.ystem
platform are listed in Table 3-              •       •     '

                           TABLE 3

     Desirable Recovery System Platform Characteristics;-

    Configuration which protects- and confines sorbent' 'ma-
    terial from wind effects during broadcasting.  --x
    Configuration which channels the sorbent material to -*
    the harvesting conveyor.                   _

    Location and support structure for harvesting conveyor.

  -  Unobstructed run for sorbent broadcasting duct.

    Location for mounting additional sweeping boom's.

  -  Minimum relative motion in waves.

    Tankage for recovered oil.
  -  Acceptable towing resistance and directional stability.

    Ease of assembly and disassembly for transport.
                               31

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A basic catamaran configuration has most of the desirable
features listed in Table 3.   In particular the area between
the hulls provides a sheltered location for broadcasting the
sorbent and channeling the sorbent to the harvesting conveyor,
The harvesting conveyor can be mounted between the two hulls.
The only advantage of a more conventional ship-like platform
would be its lower towing resistance.  Based on these con-
siderations, if a platform is to be designed specifically for
a sorbent-oil recovery system, it should be a catamaran con-
figuration.

The selection of a vessel of opportunity or a specifically
designed platform for mounting the recovery system depends
on the design goals.  Typical advantages of using either a
specifically designed platform or a vessel of opportunity
are listed in Tables ;4 and 5, respectively.

                          TABLE ^

   Advantages of Specifically Designed Recovery Platform

              Smaller Physical Dimensions

              Better Control of Broadcast Sorbent and
              Lower Sorbent Loss Rate

              Shorter Setup and Reaction Time

              Smaller Crew Required

              Lower Direct Operating Costs
                          TABLE 5

   Advantages of a Vessel of Opportunity as  Recovery Platform

              Simpler Transportation over long distances
              (only the recovery system equipment need be
              shipped)

              Lower Initial Cost

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These tables indicate that, if the system is going to be used
continuously, the operating efficiency and lower operating
cost of a specifically designed platform would dictate its
selection.  This is the case for a harbor unit which will be
used routinely to clean up small spills.  The selection is
not as clear for an unprotected water system which will be
used only occasionally against larger spills.  The specifi-
cally designed platform for the unprotected water recovery
system described in Section VII, alone will cost between
$20,000 and about $40,000 depending on whetner steel or
aluminum  construction is used.  A system mounted on a vessel
of opportunity would not require the special platform but
would require 60 to 80 feet of open water containment barrier
which could cost $8000.  The charter rate of a barge to mount
the system on would be about $100 per day.  Thus the charter
fee would equal the additional cost of this platform in be-
tween 120 and 320 operating days.  Because of this and the
increased efficiency of a specific platform, which is hard
to quantify, the unprotected water system described in
Section VII was based on a specifically designed recovery
platform.

CALCULATION OP SYSTEM CHARACTERISTICS

To illustrate the procedures for selection of the system
characteristics which are discussed above, the following
example calculation for a protected water recovery unit
is given:

     PROTECTED WATER RECOVERY UNIT
                            •
     Given:  Recovery Rate, ¥R = 3000 GPH
             Slick thickness = 1.5 mm
             Oil Viscosity < 6000 cps

     Find:   System characteristics for minimum cost

             Oil volume per ft2 of slick = 0.0368 gals/ft2

     Try:    Residence time, TR = 15 seconds

             Sorbent coverage, C  = 0.80
                                s
             From Figure 48

             Oil Recovery r}_ = 0.8?
                           A


                             33

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                                       ¥R
     -Area to be swept/hour,  A , =   nQ,gQ~~~r~ = 94,000
                              s    0.0368 x T)R   ft2/hr

      Sweep speed - U ,  ft/sec
               1 '     S
      Swe'ep width,  ¥  = A /U  ft
                    s    s  s

     .Acti'ye' length L. = U  X TR = ft
                     A    S    xl
     •A '> Sorbent chip area in2 t  = sorbent chip thickness,

     t     •*
      Sorbent broadcasting rate,

       •••• :  ''     ..     A  x c  x t
                  S    3600 X 12


      Sorbent broadcasting rate,

     ''    '         A  x C  .x 144
              • ,     O    Q             i
              N  =	, chips/sec
               C     3600 X A


    •  V ' = 0.436  ft3/sec
       S
      N \= 334 chips/sec
       VX


In order to 3elect ,a sweep speed it is necessary to have a
relationship for cost as a function of system geometry.  It
is assumed that the operating cost is essentially independent
of the sweep speed and broadcasting rate.  Thus it is  only
necessary to consider those parts of the first cost which
are; functions of sweep speed and broadcasting rate.  In order
to 'define the cost relationships it is necessary to carry
out, a. concept .design and cost estimate for the system.  This
has been done and the relationship for systems similar to
the Harbor Unit presented in Section VI is:

                               L.
Relative Cost = 22,000 (0.80 x ^ + 0.20 x  (¥s/l6)2)

                         V                  W           L
              + 15000 X 7-—- (0.55 + 0.25 X t-| + 0.20  X -£)
                              34

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The first term is related to the recovery platform and the
second term is related to the broadcasting, recovery and
regeneration equipment.  The relative cost as a function of
sweep speed is:
      Sweep Speed, U
        ft/sec      s
            1.0

            1.5
            2.0
Sweep
Width, W
  ft    £

  26.1

  17-^-5
  13-0
Active
Length, L
                                       ft
                                             A
Relative
  Cost
dollars
    15      35,800
    22.5    32,050
    30.0    33,400
This indicates that for a 15-second residence time and
80-percent sorbent coverage that the optimum sweep speed is
about 1.6 ft/sec.  The effects of residence time and per-
cent sorbent coverage can also be studied.  For example,
reductions in residence time to 10 seconds will reduce the
relative cost about 2 percent.   However, the oil recovery
ratio drops to 0.75 which departs further from the general
design goals of complete oil removal.  Thus the optimum
characteristics for a protected water sorbent oil recovery
systems are:
            Recovery Platform Type:

            Sweep Speed

            Sweep Width

            Active Length
            Sorbent Broadcast Rate
       Catamaran
       1.6 ft/sec
       16 ft
       24 ft
       0.44 ft3/sec
These characteristics will also satisfy the typical limiting
parameters listed in Table 2.  For example, the hull di-
mensions which will result from these characteristics are
such that the two hulls can be carried side 'by side over the
road.  The overall dimensions of the assembled platform are
comparable to those of other oil recovery craft, such as the
M.V. Port Service of Baltimore, which work around piers and
ships.
                             35

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Once the basic system characteristics  have  been  established,
the detailed characteristics  of the  broadcasting and  sorbent
regeneration system can be determined  using the  procedures
detailed in Appendices B and  D.
                              36

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                         SECTION VI

  3000 GALLON PER HOUR RECOVERY SYSTEM PRELIMINARY DESIGN

A preliminary design of a sorbent oil recovery system for
.us.e in protected waters was prepared based on the general
and specific design goals provided by the EPA,  These
specific design goals are given in Table 6.

                           TABLE 6

    Specific Design Goals for Protected Water System

a.  Environment

    Perform effectively in harbors and other protected
    waters with 2-foot waves in combination with 20-mph
    winds and 6-knot currents.

b.  Sorbent Recovery System

    The sorbent recovery system in combination with neces-
    sary oil-water separation facilities shall have the
    capacity to recover at least 1,500 gal/hr of oil with
    10 percent or less water content.  However, a ^,,000
    gal/hr with 10 percent or less water content oil re-
    covery rate would be a desired optimum rate.

    (l)  The sorbent system shall be capable of meeting the
         recovery rate objective while recovering oils with
         viscosities ranging from that of light diesel oil
         to near water density heavy asphalt at 20°C.

    (2)  The thickness of the slick to be recovered at the
         specified rate shall be 1.5 mm or less.

    "(3)  The device may include as an integral part of the
         skimming process, a system of booms to aid in
         herding oil toward the harvesting device.  How-
         ever, emphasis shall be given to the skimming
         process rather than the design of the boom.

    (4)  Designed units proposed for temporary attachment
         to existing vessels must consider transport need
         and ease of installation,wi.th a-	minimum of special
         equipment.         ^^'
                           s"
                          s'
                              37

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c.   Oil-Sorbent Separation

    The unit must be capable of operating under hydraulic
    loadings' and ranges  of oil  concentrations  consistent
    with the performance of the oil  harvesting devices.   It
    must be capable of producing output  streams with the
    following characteristics:

    1.   Oil - 10 percent water  or less.

    2.   Sorbent material - available for reuse or  method for
        disposal.

    3.   Water - 10 mg/1  oil or  less.

d.   Oil Storage or Disposal

    Specify floating or  appropriate  land-based facilities
    which in combination with any on-board storage will
    have capacity to store .material  to be collected from
    spills of at least 200,000  gallons of oil  plus agglome-
    rates.  Agglomerates must be processed before  land dis-
    posal to preclude leaching.   Other appropriate disposal
    techniques such as incineration  will be considered as
    alternatives.

e.   Vessel

    Recovery equipment may be designed for either  permanent
    or  temporary mounting on an appropriate vessel.   Vessels
    must be capable of speeds of at  least 12 knots under the
    environmental conditions listed  above (however not per-
    forming the oil recovery function).   The vessel must
    accommodate the oil-sorbent recovery device, any required
    oil-water separation equipment,  operating  personnel, eight
    hour fuel supply and all oil specified for storage on
    board.  It must be sufficiently  maneuverable to minimize
    time lost in recovering oil from constricted locations
    and be capable of operating in waters as shallow as
    3-foot depth.
                              38

-------
The system was designed to satisfy these desired recovery
rates of 3000 GPH of heavy oil at 20°C,  For design purpose,
the heavy oil was taken as bunker "C" with a specific gravity
of 0.98 and a viscosity of 4,500 centepoise at 20°C.  The
rationale for the selection of the system operating param-
eters such as sweep speed, sorbent coverage .and sorbent
residence time are presented in Section V.

GENERAL DESCRIPTION

The basic sorbent recovery system consists of a pneumatic
broadcasting system with a moving parallel plate nozzle, a
harvesting conveyor, a transfer conveyor, a sorbent re-
generator, the necessary drive systems, and a catamaran type
platform.  The basic characteristics of the system are pre-
sented in Table 7.  Figure 10 presents an overall arrange-
ment drawing of the complete system.  The sorbent material
to be used and the recovery performance over a range of con-
ditions are also given In Table 7.

RECOVERY SYSTEM COMPONENTS; BROADCASTING SYSTEM

The design of the pneumatic broadcasting system and broad-
casting nozzle was based on the design procedures presented
in Appendix B.  This system is required to move and dis-
tribute 330 3 in. X 3 In. x 1/4 in.  sorbent chips per
second.  The technical and performance characteristics of
the broadcasting system are presented in Table 8.  The
system uses an off the shelf industrial fan with a long
shavings type wheel.  The only non-standard component in
the system is the broadcasting nozzle.  The nozzle plates
are oscillated with a mechanical linkage driven by an air
cylinder.

Harvesting and Transfer Conveyors

The harvesting conveyor is mounted between the hulls of the
recovery platform.  It has an overall width of 8.0 ft and a
length between sprocket shafts of 9.0 ft.  The conveyor is
made up of two 4-ft wide, belts.  These belts are supported
on their edges and centerlines by a  support frame which
also carries the sprocket shafts.  The technical character-
istics of the harvesting conveyor are presented in Table 9.
                               39

-------
                         TABLE 7

           Characteristics of Protected ¥ater
               Sorbent-Oil Recovery System
Design Oil Recovery Rate           3000 gallons/hr
Slick Thickness                    1.5 mm
Sweep Speed                        1.6 ft/sec
Sweep Width (Normal)              16.0 ft
Sweep Width (Extension Booms)     32.0 ft
Active Length                     24.0 ft
Sorbent Material                   Open cell reticulated
                                     polyurethane foam
Sorbent Form                      Chips 3 in.  X 3 in.
                                   x 1/4 in.  nominal
Sorbent Pore Size
     Oil Viscosity < 1000 cps      80 PPI
     Oil Viscosity > 1000 cps      30 PPI
Sorbent Residence Time             15 sec
Sorbent Coverage                   80 percent

                Oil Recovery Performance

                 1.5 mm Slick Thickness

Oil Viscosity Oil Recovery Rate  Oil Recovery  Water Recovery
     cps             GPH         from Slick        Rate
                                   percent          GPH

   < 6000           3000             87            311
    10000           2830             82            270
    20000           2580             75            243


          Oil Recovery for Viscosity < 6000 cps

Slick Thickness  Normal Sweep Width  With Extension Booms
     MM           (16 ft) GPH         (32 ft) GPH

      0.5                1000                2000
      1.0                2000                4000
      1.5           '     3000                6000
                             40

-------
4=-
h-1
                            TRANSFER
                            CONVEYOR
HARVESTING CONVEYOR

         38.5 DIESEL ENGINE

                     STEAM GENERATOR
                                                                                                      32'-0"
                                                                                  BROADCASTING
                                                                                  NOZZLE
                                        BROADCASTING FAN
                           SORBENT REGENERATOR
                                    FIGURE 10 - PROTECTED WATER RECOVERY SYSTEM ARRANGEMENT DRAWING

-------
                         TABLE 8

           Broadcasting System Characteristics
Sorbent Form

Sorbent Broadcasting Rate

Regenerated Sorbent Density
Broadcasting Nozzle Type
Nozzle Rate
Nozzle Angle
Nozzle Drive
Broadcasting Duct Diameter
Broadcasting Duct Length
Air Speed
Air Flow Rate
Fan Type
Diameter (Wheel)
RPM
Fan Power (Total)
Transmission
Total Sorbent in System
Chips 3 in.  x 3 in. x I/1!- in.
                   nominal
       0.424 ft3/sec
       330 chips/sec
       6.0 lbs/ft3
       Moving Parallel Plate
       1 cycle/sec
       ±50 degrees
       Air Cylinder
       1.0 ft
      24.0 ft
       45 ft/sec
       2062 ft3/min
       American Blower Series
                        106
       Industrial Fan-Size 17
       Long Shavings Wheel
       29-5/8 in.
       1062
       7.8 HP
       Mechanical
       14.9 ft3
       11,450 chips
                    Sorbent Loss Rate
            Wind Speed
               mph

             0-10
            10 - 20

            20 - 30
       Loss Rate
        ft3/hr

         3.1
        15.5
        31
                             42

-------
The hydraulic drive system can provide an excess of 150
ft-lbs of torque at 47 rpm.  This is sufficient to lift a
combined weight of chips and debris of about 400 Ibs.  The
belt material and sprockets for the conveyor are off the
shelf items.  The support frame will have to be fabricated.
                           TABLE 9 .
             Harvesting Conveyor Characteristics
  Conveyor Width

  Conveyor Angle
  Conveyor Length
  Linear Belt Speed
  Belt Material
  Belt Drive

  Power
  Transmission
  Conveyor Support
Total 8.0 ft - 2 sections
4.0 ft
45 degs.
9.0 ft
1.6 ft/sec
1 in. X 1 in. mesh extra
heavy duty (button head weld)
flat-wire belt galvanized
steel construction
16 Class C sprockets
8-1/4 in. diameter - 23 teeth
1.0 HP
Hydraulic
Integral support frame
The transfer conveyor collects the chips from the har-
vesting conveyor and transports them to the sorbent re-
generator.  This conveyor has a belt width of 2.0 ft and a
belt speed of 2 ft/sec.  The requirements for this conveyor
can be satisfied with commercial units which are available
off the shelf.  The detailed technical characteristics of
the transfer conveyor are presented in Table 10.

-------
                          TABLE 10
              Transfer Conveyor-Characteristics
   Conveyor Belt Width

   Conveyor Length
   Linear  Belt Speed

   Belt  Material


   Conveyor Support

   Drive

   Power

   Transmission
 2.0 ft

11.5 ft
 2 ft/sec
 3 ply stitched canvas
   Neoprene covered

 Troughed bed* with integral
 take up and driver pulley

 8 in. pulley-friction drive

 1/2 HP
 Hydraulic
   *  Hytrol  Conveyor  Co. Model  "TR" Horizontal Belt
      Conveyor  or  Equivalent.
 Sorbent  Regenerator

 The  preliminary  design of  the sorbent regenerator was based
"on the development work and data presented in Appendix D.
 The  characteristics of the resulting unit are presented in
 Table  11.   Figure 11 presents an arrangement drawing for
 the  unit.   The various elements are indicated in the figure,
 The  design  closely follows that of the sorbent regeneration
 test apparatus.  The most  important differences are the ad-
 dition of a  third pair of  squeezing rollers and the use of
 a  reinforced neoprene covered belt in place of the upper
 wire-mesh belt with pads.  Other mechanical improvements
 suggested by the development program and detailed in Ap-
.pendix D.have been included.  In .addition^ the collecting
 pan  between the  legs of the lower belt has been deepened
 and  provisions made for heating coils.  The development
 tests  showed that cold bunker "C"  (lO°C 20,000 cps) could
 be squeezed from the sorbent and through the lower belt.
 However., for satisfactory  flow in the collecting pans the
 recovered oil must be heated.  This will require about
 1000 pounds  of steam per hour.  This steam can be supplied
 by a commercial  steam cleaning unit.

-------
                        TABLE 11

           Sorbent Regenerator Characteristics
Design Sorbent Rate
Belt Speed
Maximum Squeezing Force
Number of Squeezing Stations
Squeezing Roller Width
Squeezing Roller Diameter
Lower Belt Material

Upper Belt Material
Power
Transmission
Air Supply
Squeezing Force Generation
Squeezing Roller Travel
Heating
               0.43 ft3/sec
               1.0 ft/sec
               220 Ib/in. of belt width
               3
               24 in.
               6 in.
               Steel Balanced Belting
               Type B-60-32-14
               Reinforced Neoprene
               2 HP
               Hydraulic Drive
               Engine Driven Compressor
               Air Cylinder
               4 in.
               Heating coils in collecting
               pan 1000 Ib/hr steam
            Sorbent Regeneration Performance

Oil Viscosity  Sorbent  Squeezing Force Regenerated Sorbent
                                              Density
     cps

      2
    300
   1000
   4500
 20, 000
PPI

80
80
30
30
30
Ib/in

  220

  220

  220

  220

  220
lb/ft=

 4.5
 5-5
 5-0
 5.5
 7-5

-------
LOWER BELT
STEEL WIRE MESH
      UPPER BELT
      NEOPRENE
                              _ .  ,-, HYDRAULIC MOTOR
                             yf^> i  s~^\^
              AIR ACCUMULATOR.
                          SQUEEZE ROLLER
                          FRAME ( 3 )
   BELT TENSION ROLLER
        OIL DISCHARGE PIPE ( 2 )
ACCUMULATOR

     AIR CYLINDER
                                                                   PPER BELT

                                                                  LOWER BELT
                                                            BRUSH
                          STEAM LINES FOR
                          OIL HEATER
FIGURE 11 - SORBENT REGENERATOR ARRANGEMENT DRAWING

-------
Although the sorbent regenerator is the most complex mechani-
cal element in the recovery system and is not a standard item,,
many of its components are commercially available.  These in-
clude belts, air cylinder,, shafts and bearings.  The con-
struction of the regenerator requires machine shop and light
steel fabrication capabilities.  These capabilities are
readily available.                      !

Miscellaneous Equipment

In addition to the main components of the recovery system,
certain additional equipment are required to complete the
recovery system.  These include an oil transfer system to
pump the recovered oil to storage, and a heating system for
the sorbent regenerator and tank heating.

The oil transfer system will use a centrifugal pump driven
mechanically off of the broadcasting system fan .drive.  The
pump selected is a centrifugal pump, MP Model 130 or equal,
bronze body, 188 gpm at 15 feet of head.

The heating of the tanks and sorbent regenerator, if-re-
quired, is best provided by steam.  Also steam may be re-
quired-: for cleaning.  The most economical way of providing
steam for these purposes is with a commercial steam cleaner
unit.  A suitable unit would be a Slifer Model 90 or equal
with a capacity of 60 gph at 120 psi.

Power and Transmissions

The various components of the recovery system require a
rugged and reliable power supply.  For this purpose an in-
dependent power system"consisting of a diesel engine with
a hydraulic or combination hydraulic and mechanical trans-
mission system was selected.  The engine is a 38.5 HP
radiator cooled Model 5034-7201 Detroit Diesel or equal.
The radiator cooling makes the recovery unit independent of
a supply of uncontaminated water for cooling and allows op-
eration in cold weather by the addition of antifreeze.

The recovery system components consist of two types with
respect to power transmission.  The broadcasting system fan,
the oil transfer pump, and the bilge and ballast pump  (which
is not part of the recovery system) require moderate powers
at moderate rpm's.  The harvesting and transfer conveyors
and the sorbent regenerator require low power at low rpm's.

-------
In both cases some independent speed control capability is
desirable.  As a result,  it is desirable to have two separate
power transmissions.   The fan and pumps system could be
either a direct mechanical or a hydraulic system.   Diagrams
for the mechanical and the hydraulic transmission systems are
given in Figures 12 and 13, respectively.  The mechanical
transmission is less  costly but restricts the arrangement of
components.  The hydraulic transmission is more costly but
allows a much greater freedom with qomponent arrangement. Both
systems consist completely of commercial components which have
a history of satisfactory operation.   The hydraulic lines
would be fitted with quick disconnect fittings which will al-
low rapid assembly and disassembly of the unit.   In this case,
a satisfactory "arrangement can be made with the mechanical
system so it is recommended because of the lower cost.

The transmission system for the sorbent regenerator and con-
veyor should be hydraulic.  Hydraulic motors are available
which are well suited to  the required low rpm, high torque
operation.  Also a hydraulic system allows some speed adjust-
ment and is much more easily arranged than a mechanical sys-
tem.  Figure 14 presents  the flow diagram for the sorbent
regenerator and conveyor  hydraulic transmission.   Again the
system consists of commercial components with a history of
satisfactory operation.

RECOVERY PLATFORM

The recovery platform is  based on a catamaran concept with
asymmetrical hulls configured to confine and herd the sor-
bent material.  The harvesting conveyor is mounted between
the hulls.  Figure 10 presents an overall arrangement of the
recovery system equipment and platform.  The basic charac-
teristics of the recovery platform are presented in Table 12.

Hull

The platform structure is composed of two asymmetrical hulls
joined by two tubes.   The tubes are fastened to the hulls
with stainless steel  bolts in such a manner that they can be
disassembled for shipment.  The hulls are each fitted with
five watertight compartments for machinery, sorbent storage,
recovered oil, and ballast.  Figure 15 shows the internal
arrangement of the hulls.

-------
      BILGE PUMP-
                       11
             REDUCER
XA
                            OIL TRANSFER PUMP
                                       TO FAN
                                 •38.5 HP DIESEL
FIGURE 12 - DIAGRAM OF FAN AND PUMP MECHANICAL TRANSMISSION
         FOR 3,000 GPH  SYSTEM

-------
         JYRONE 20200 PUMP
          30GPM@2000PSI
        DELTA FLOW DIVIDER
       WITH SPECIAL 2:1 RATIO
                                                                 BLOWER FAN
                                                               DOUBLE "A" MH39
                                                                ,  MOTOR
                                                               510Lb.Jn.@
                                                                 1240 RPM
DIESEL ENGINE
  38*H.P.
                                                              OIL TRANSFER
                                                            DOUBLE "A" MH-10
                                                                MOTOR
                                                              83 Lb. ln.@
                                                               3000 RPM
                                                        BILGE PUMP
                                                     DOUBLE  "A" MH-10
                                                         MOTOR
                                                       83 Lb. ln.@
                                                         3000RPM
     FIGURE 13 - SCHEMATIC DIAGRAM OF FAN AND PUMP HYDRAULIC TRANSMISSION
               FOR 3000 GPH SYSTEM
                                     50

-------
 TYRONE 20150 PUMP
 20GPM@2500PSI
DIESEL ENGINE
•-Q
                                               L-H
                                                                    SORBENI
                                                                  REGENERATOR
                                                                    STAFFA B-30
                                                                     . MOTOR
                                                                  400 Lb. Ff.@
                                                                  38-125 RPM
                                                                   HARVESTER
                                                                  STAFFA B-10
                                                                    MOTOR
                                                                  142 Lb. Ft.@
                                                                  47-100 RPM
                                                                   TRANSFER
                                                                   STRAFFA B-10
                                                                     MOTOR
                                                                 36 Lb. Ft. @
                                                                   150-250 RPM
         FIGURE 14 - SCHEMATIC DIAGRAM OF SORBENT REGENERATOR AND CONVEYOR
                   HYDRAULIC TRANSMISSION FOR 3000 GPH SYSTEM
                                      51

-------
                        TABLE 12

                Platform Characteristics
Platform Concept
Overall Length
Overall Beam (Normal)
Overall Beam (Extension Booms)
Draft (Maximum)
Hull Beam
Hull Depth
Hull Structure
Light Ship Weight
Service Loads
Recovered Fluid (3000 gallons)

Full Load Condition
Deployment Draft
Full Load Draft
Propulsion                2
Deployment Speed
Full Load Speed
On Board Chip Storage
                                  Catamaran
                                  42.5 ft
                                  16.5 ft
                                  32.5 ft
                                   3.0 ft
                                   4.25 ft
                                   5-5 ft
                                  Aluminum
                                  17,100 Ibs
                                   2,190 Ibs
                                  22,610 Ibs
                                  41,900 Ibs
                                  1.33 ft
                                  2.83 ft
                              75 HP Diesel I/O Drives
                                 10.6 knots
                                  8.4 knots
                                  240 ft3
Item
         Length
           ft
2 hulls   42.5


           8.0
2 cross
  beams
1 deck
  house   11.5
Shipping Characteristics

    Width     Depth     Estimated Weight
     ft        ft            Ibs

     4.5       8.0        6000  max.


     2.0       1.25        500


     5.0       7.5        1200
                             52

-------
       QAWT
                                         SORBENT     BALLAST
                                         STORAGE
MACHINERY/ SORBENT
  SPACE  /VSTORAGE
             FIGURE 15 - INTERNAL ARRANGEMENT OF PLATFORM HULLS
                                    53

-------
The hull structure can be either aluminum or steel.   Aluminum
has the advantages of lower weight for greater onboard oil
storage and shipping, and lower maintenance costs.   A steel
hull will have a lower initial cost and higher weight.
Aluminum construction including hulls,  cross-beams,  and the
deck house will have a weight of 8600 Ibs and a cost of
&25,200 (each of 3).  The comparable items in steel  will have
a weight of 20,000 Ibs and a cost,, with inorganic zinc coating,
of $17,550 (each of 3).   The characteristics presented in
Table 12 are based on aluminum construction.  Figure 16 pre-
sents a typical midship section for aluminum construction.
As may be noted, the construction details are very simple so
that the structure can be fabricated by any facility used to
working with aluminum.

Propulsion

It has been assumed that the protected water sorbent-oil
recovery system will be regularly used for cleaning  up
routine harbor spills.  As a result, it is desirable to
provide some form of self-propulsion rather than to  use
another vessel for towing or pushing.   The speed-power
curves for the recovery system at its  full load and  deploy-
ment draft are presented in Figure 17.   The specific design
goal of a deployment speed of -12 knots would require a total
of about 240 HP.  This power level exceeds the power avail-
able from lightweight propulsion systems.  A reduction in
speed to 10 knots reduces1 the required power to 125  HP which
is within the practical rang.e.  The available lightweight
and low-to-moderate cost propulsion systems include  gasoline
outboard motors or diesel inboard outdrives (l/0's).  In-
board gasoline engines could provide higher power levels
but could not satisfy U. S. Coast Guard Regulations  for
this type of craft.

The advantages of gasoline outboard motors include light-
weight, low first cost,  and good reliability.  Their dis-
advantages are high operating cost and short life.   For
this application, two mercury Model 650 AC outboard  or
equivalent at about 80 HP each would be satisfactory.  The
advantages of diesel I/O's include low operating cost, good
reliability and long life.  However, they are heavier
(about 1200 Ibs) and more expensive (about $4700) than
gasoline outboards.  For this application two Volvo-Penta
                             54

-------
       BULKHEADS 0.160 " R. w /3" X 3/16 " FRAMES ON 12" CENTERS
SIDE 3/16" II
                          DECK 3/16 " 9. AFT OF BREAK, 0.160 " FWD
                        3X 3X 3/16" ANGLE
LONG. 6X 3/8" FB
                         ALL FRAMES WITH 3/16 "I
                         3"X 1/4" F.B. AND WITH
                         0.16013"X 3/16 " F.B.,
                         ALL ON 12" CENTERS
SIDE 3/16" d
                                                  BUMPER  SPLIT 4" OD
                                                  PIPE W/0.318 "WALL
                                                  OUTBOARD SIDE ONLY
                         BOTTOM 3/16" I
                 STARBOARD HULL LOOKING FORWARD
                     8'-0" FORWARD OF TRANSOM
              ALL WELDED 5086 - HI 11 AND H 32 ALUMINUM
         FIGURE 16 -MIDSHIP SECTION FOR ALUMINUM CONSTRUCTION

-------
                        10       12
                    SPEED ( Knots )
14
16
FIGURE 17 - SPEED POWER CURVES FOR PROTECTED WATER
           OIL RECOVERY UNIT

-------
Inc.  Model AQ D32A/270D or equivalent dlesel outdrives at
about 75 HP each would be satisfactory.  If the recovery
system is likely to be used on a dally basis it is recom-
mended that the diesel outdrives be fitted.  The arrangement
drawing presented in Figure 11 is based on the use of diesel
outdrives.
Outfit
In order to make the recovery platform an operational system,
a certain amount of outfit is required.  The typical outfit
items are listed in Table 13.
                          TABLE 13
                        Outfit Items
           Railings
           Hatches
           Anchor and Lines
           Fenders
           Fire Extinguishers
           Lights
Lockers
Cleats
Piping
Chemical Toilet
Compass
Radio
The extent of the outfit depends on the service the re-
covery platform will see and the requirements of the par-
ticular owner.
WEIGHT ESTIMATES
A detailed weight estimate was prepared and is presented in
Table l1^.  This weight estimate is based on aluminum con-
struction and propulsion with diesel outdrives.  If steel
structure is used instead of aluminum, the total structural
weight would increase to about 20,000 Ibs.   This would re-
duce the amount of recovered oil which could be carried at
a draft of 2.75 ft to about 1350 gallons.
                              57

-------
                                                                         TABLE 14


                                        Weight  Estimate for 3COO .GPH Protected Water Sorbent-Oil Recovery  System


                          CALCULATION OF WEIGHT
VJ1
co
                                                                                                                1 of 4
*" Protected Water Unit
ITEM Structure
Bottom
Deck
Sides'
Transom
Bulkheads
. . . . . I-or.-itu Jinal Web .
.. Rub Fte i 1 . :
Fv*. Peam . . .
Aft. Beam
Ho.use . .
Gratin?
Miscellaneous . .
Total Structure

Mechanical Systems
Saueezer
Fan
Harvesting Convevor
Broadcast Duct
Hydraulic and Mechanical Drive
Diesel

Total Mechanical Systems

1"
(EIGHT III
Ibs
829
756
2945
126
- 33°.
42-=.
. 1Q4
. .4 1C. ..
218
840 '
465
1000
8600


700
4?5
SOD
320
1150
1200

4335

ABOVE MLO BASF LINE
C.G.
























VERT. MOM.




















-



REFER.CO TO, Transom
C.G.
























rm MCMCNTS












l6o, 2CO









48,205

OM^IU
c.e.

















«






AFTER MOHEHTS
























wm tioia

-------
                                                                    TABLE 14 (Continued)
                       CALCULATION OF WEIGHT
2 of 4
v_n
VD
SHI* Harbor Recovery Unit
ITEM Outfit
Railings
Hatches
Anchor
Fencer?
Pire Extinguishers
Lights
Lockers
Cleats . •
Piolng '.
Chemical Toilet
Comoass
Radio
Miscellaneous

Total Outfit

Propulsion Machinery
2 Diesel I/0's with Dover tilt,
Steering Battery, fuel tank





Mn l WWIM
HEIGHT IN
Ibs
1?C
SCO
125
150
?CO
50
50
50
4^0
SO
10
30
140

1585



1620





JMOVE MLO B*SF LINE
c.e.
























VKT. MOM.
























ffiFcimcD TO; Transom
c.e.
























FHO MOMENTS














31539



3240





CHf^m
c.e.
























AFTE* MOMENTS
























•01H SIMS

-------
                                                                    TABLE 14  (Continued)
                        CALCULATION OF WEIGHT
                                                                                                                of
O\
O
9I" Harbor Recoverv Unit
ITtM Service load

Fuel-Diesel
Personnel and Effects
SnrhPnt Chips
Fresh Vfater

Total Service Load

Cars;o - ^COO Gallons at 7.5 IbAal
Recovered Oil


	 ' 	



^ i^ — — ^ •"— — «^ —





•nn 1
HEIGHT IN
Ibs

600
500
600
160

1Q60


22610












ABOVE MLO BASF LINE
C.G.






















VERT. MOM.






















REFERRED TO. Transom
C.6.






















rm MOMENTS






26000


358000






•^^^••M^BtmvMVM





&.
C.G.






















AFTER MOMENTS
















*«w*v»«4iwH^viv^"viWb»





wlH VlB^S

-------
                                            TABLE 14 (Concluded)
CALCULATION OF WEIGHT
                                                                                         of
»"• Harbor Recovery Unit
ITE* Summary

Structure
K;-'Ch~p.ical SVP terns
Outfit
Pro--".;! o •' on Kn cM no''"
Margin
,.
Light Shlo

Service L-ia-'?

.Service Condition (Draft - l.?5 ft)

Recovered Oil "COO era] Ions

Full Load Condition (Draft = ? .^ ft)









WEIGHT IN
Ibs

S6ro
•U3S5
1*35
i fipo
71^

16Q55

lo'-o

18915

??^10

^1525 '








ABOVE MU> BASF LINE
C.G.
























venr. MOM.
























BErtRREo TO: Transom
C.G.







15. f



15..2*

15..'5j

15.6








no MOMCMTS







26^ , c cc

2"6,CCC

2?2, COO

^50,000

650., ooo









C.6.
























*f TEd HOMCNTS
























•OIK SIBU -

-------
CREW AND OPERATING PROCEDURES

The protected water sorbent-oil recovery system should be
operated by a three-man crew consisting of a captain,
engineer and deck hand.  The duties of these crew members   '>
are listed in Table 15.  Although the sorbent broadcasting,,
recovery, regeneration cycle is an automatic one, some as-
sistance will be required from the crew.   The most important
is the removal of large pieces of debris  and driftwood picked
up by the harvesting conveyor.  These items would be removed
from the transfer conveyor or the inlet of the broadcasting
fan.  Also the crew must introduce the sorbent material at
the start of the operation or makeup sorbent during the op-
eration.  The sorbent material will be pre-cut and stored
aboard in bags.   It is introduced into the system by dumping
it on the transfer conveyor with all components running.   If
the slick is thin or discontinuous, the sorbent should be
prewetted with the diesel oil carried onboard.   This will
limit the amount of water recovered.  At  the end of the op-
eration, the sorbent material is recovered by stopping the
broadcasting system and collecting the sorbent in bags as
it comes out of the regenerator.

On arrival at the scene of a spill, the sweeping booms are
extended, if required, and the sorbent material introduced
to the system.  The recovery platform is  then driven into
the slick and continues sweeping at the selected speed until
the slick is recovered.  Since the operation is independent
o-f platform draft, no ballasting is required.   If the  slick
is In a restricted area,  such as between  a ship and pier,
a different operating procedure will be required.  The re-
covery platform would be positioned in the slick and stopped.

The sorbent material would then be herded back to the
harvesting conveyor by the crew using rakes.   Operating in
this manner,  the recovery rate would be much less than the
design rate.

When the oil tanks are full, the oil-transfer system would
be used to pump out onto an accompanying  barge or at a
shore-side facility.  At the conclusion of the recovery op-
eration, the sorbent material is recovered for reuse and the
equipment cleaned and repaired as required.  Much of the
sorbent that is  lost during the recovery  operation may be
expected to remain in the area of the spill.   This sorbent
                              62

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                      TABLE 15
          Duties of Recovery System Crew
Captain
        Direct the oil recovery operation
        Control the speed and location of the recovery
        platform
        Duty Station:  Pilot House
Engineer
        Control Recovery Machinery
        Repair and Maintain Machinery
        Operate Oil Transfer and Ballast System
        Assist Deck Hand
        Duty Station:  Recovery Machinery Controls,  Port
                       Side Aft.
Deck Hand
        Introduce Sorbent Material into System
     -  Remove Larger Pieces of Debris from Transfer
        Conveyor
     -  Repack Sorbent Material
        Handle Lines
        Duty Station:  Grating aft of transfer conveyor.
                              63

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can be recovered by resweeping the area with the broadcasting
system off.  This will require an expenditure of personnel
time but may be required and could be economically desirable
if the sorbent losses are large (high winds).  The resweeping
operations could be carried out at a higher speed than the
basic recovery operation.

COST ANALYSIS

A detailed analysis was made of the construction and op-
erating costs of the 3000 GPH protected water recovery sys-
tem.  The following assumptions were used in this analysis:

     -  The costs apply only to "following systems" after a
        prototype system has been proven and a complete cor-
        rected set of specifications and plans are available.

        The estimates are based on construction in flights
        of 1 and 3 units.

        The builder is to be experienced with all types of
        fabrications and machinery installation required
        and the facility is to be equipped to handle this
        size job.  Experience is required in steel or
        aluminum fabrication, diesel-hydraulic machinery,
        and workboat outfitting to USCG regulations.

        Only commercial quality construction is required
        without extensive reference to government specifi-
        cations or special inspection.

        Costs are based on Spring 1972 dollars.

The construction cost estimates were made by summing the
total cost of purchased components and the value of the man
hours needed to assemble these components.  A man-hour was
valued at $12.00 including overhead and profit.  In the
case of the platform structure, budget prices were obtained
from fabricators based on preliminary drawings.  The sorbent
material has a basic cost of $6.60 per ftsin bulk form.  The
material can be cut into chips with a band saw at the rate
of about 4000 chips/hr.  This gives a total cost of $9.20
per ft3 cut into chips.
                             64

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The construction cost will depend on  the type of structure,
the type of propulsion, and  the  extent  of  the outfit.  The
selection of these  items depends on the intended duty, and
the importance of initial  cost.  The  construction cost data
are presented in Table  16  for  the various  system elements.
Various possible cost options  are presented  in Table 17
ranging from minimum initial cost to  the complete system
fitted for Independent  operation.  The  arrangement drawings,
characteristics tables  and weight estimates  presented above
are for the complete system  fitted for  independent operation.

The recovery machinery  is  common to all users and is the
heart of the system.  As a result, a  detailed analysis of
the recovery machinery  construction cost estimate is given
in Table 18.

The operating costs will depend  on how  and by whom the re-
covery system is operated.   The  direct  operating costs were
estimated on a per  hour of effective  oil recovery and per
hour of deployment  time.   The  results are  presented in
'Table 19 and are based  on  a  crew cost of $-10. per man hour.
Costs are given based on a 10  to 20 MPH wind and no attempt
to recover sorbent  and  on  a  resweep of  the slick area which
recovers 70 percent of  the lost  sorbent.   If the recovery
operation were carried  out by  a  spill control contractor a
charge would be made to cover  the capital  cost of the equip-
ment.  Typical rates currently charged  are 0.0025 times
initial cost per hour.  This would amount  to between $100
and $175 per hour depending  on the unit used.

It is of interest to note  that even when 70  percent of the
sorbent is recovered, about  65 percent  of  the direct op-
erating cost is associated with  the recovery and replacement
of lost sorbent.  This  could pay for  a  considerable increase
in platform cost to reduce the sorbent  loss  rate.

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                TABLE  16

3000 GPH Protected Water Recovery System
              Cost Analysis

Summary
Harbor Recovery Unit
Recovery Unit -
Installed and Op-
erating:
Combined Mechanical
and Hydraulic Drive
Full Hydraulic Drive
Hull -
Open Operating Station:
Steel
Steel with inorganic
zinc coating
Aluminum
Enclosed Operating
Station:
Steel
Steel with inorganic
«inc coating
Aluminum
Outfit -
Minimum - Steel
- Aluminum
With enclosed house :
- Steel
- Aluminum
With enclosed house
and self propulsion
- Steel
- Aluminum
Independent Operation
- Steel
- Aluminum
Propulsion
Twin Diesel I/O
Twin Outboards
Supply of Sorbent
Material (?'m ft)
Dollar Total for 1
Material




1^090,
1^050.


13000.

17000.
2';500.


15000. .

19500.
28000.

?590.
3030.

5850.
7580.


676O.
8-50.

73': o.
9900.

7330.
r:870.

2?10.
MH




668.
6M .


-

-
-


-

-
-

2': 8.
2':8.

306.
306.


358.
358.

'400.
•'•00.

SO.
50.

-
Total




22110.
22780.


13000.
'
17000.
2^500.


15000.

19500.
?8ooo.

5570.
6010.

9520.
11P50.


11060.
12950.

126'.0.
1^700.

8790.
3JI70.

2210.
Dollar Total ea of 3
Material




12^00.
132^0.


11700.

15300.
22050.


13500.

17550.
25200.

?280.
2270.

5150.
6670.


5950.
7610.

6890.
8700.

7050.
2730.

2210.
MH




587.
567.


-

-
-


-

-
-

218.
218.

269.
269.


315.
315.

352.
352.

72.
48.

-
Total




19^50
200^0.


11700.

15300.
22050.


13500.

17550.
25200.

iigoo.
5290.

8380.
9900.


9730.
11390.

11110.
12920.

7910.
3310.

2210.
                   66

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                TABLE 17

3000 GPH Protected Water Recovery System
        Total Construction Costs

Minimum Initial Cost:
Recovery Unit -r Combined Me-
chanical and Hydraulic Drive
Uncoated steel hull
Minimum outfit (steel) w/o
sweep booms
Outboard motor propulsion
Total w/o sorbent material
Sorbent material
Total with sorbent material
Minimum Intermittent Duty:
Recovery unit -combined mech.
and hydraulic drive
Coated steel hull (open op-
erating station)
Outfit (open operating station)
Outboard motor propulsion
Total w/o sorbent material
Sorbent material
Total with sorbent material
Minimum Continuous Duty Unit:
Recovery unit-combined me-
chanically and hydraulic drive
Aluminum (open operating stat. )
Outfit (open operating station).
Twin Diesel Propulsion
Total w/o sorbent material
Sorbent material
Total with sorbent material
Independent Operating Unit:
Recovery unit - Full hydraulic
Drive
Aluminum Hull, enclosed house
Outfit - Independent operation
Twin Diesel Propulsion
Total w/o sorbent material
Sorbent material
Total with sorbent material
Dollar Total
for 1


22110.
13000.

5570.
3^70.
44150. >
2210.
46360.


22110.
i
17000.
5570.
3470.
48050.
2210.
so, 260.


2211C.
24500.
6010.
8790.
61410.
2210.
63620.

22780.
28000.
14700.
8790.
74270.
2210.
76480.
Dollar Total Each
of 3


19450.
11700.

4900.
3310.
39360.
2210.
41570.


19450.

15300.
4900.
3310.
42960.
2210.
45170.


19450.
22050.
5290.
7910.
54700.
2210.
56910.

20040.
25200.
12920.
7910.
66070.
2210.
68280.
                  6?

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                         TABLE 18

         Detailed Analysis of Protected Water Unit
                  Recovery Machinery Cost
Oil Recovery Machinery -
     'Cost of materials and fabrication of components in-
      cluding hydraulic system hook-up)
Squeezer
Fan

Harvesting conveyor
Broadcast duct
Broadcast nozzle
Transfer conveyor
Hydraulic drive
Mechanical drive


Diesel

Transfer pump

Total for 1
Total each for 3 @ .
Additional for full
    hydraulic drive

Total for 1
Total each of 3 ® .8
                             &3000.
                               550.

                              1400.
                               200.
                                50.
                               800.
                              5360.
                               500.


                              2100.

                               130.

                             14090.
                             12'-! 00.

                               960.

                             15050.
                             13240.
210 MH
 50

 16
  8
 48
 40
380
334

+24
404
356
fabricated
purchase
complete
fabricated
purchased
fabricated
purchased
purchased
components and
hook-up required
purchased
components and
hook-up required
purchased
complete
purchased
Install and trouble-shoot recovery system (hydraulic and Mech)

                                       288
                                       253 (full hydraulic
                                                system)
                                       240
                                       211
Total for 1
Total for each of 3
Total for 1
Total each of 3
                              68

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                         TABLE 19

         3000 GPH Protected Water Recovery System
                  Direct Operating Costs
Per Hour of Effective Oil Recovery:

     No lost sorbent recovery1
          Crew                          $30.00
          Maintenance                    10.00
          Sorbent                       142.50 (10-20 MPH
                                                 wind)
          Fuel and Miscellaneous         10.00
          Total                        $192.50
70 Percent Lost Sorbent Recovery on Second Sweep:2

     Crew                                60.00
     Maintenance                         20.00
     Sorbent                             42.75
     Fuel and Miscellaneous             '15-00
     Total                             $137-75
Per Hour of Deployment:

     Crew                                30.00
     Maintenance                          4.00
     Fuel and Miscellaneous               7-50
     Total                              $41.50


1  No attempt is made to recover the sorbent material  lost
   due to wind.

2  A second sweep of the slick area is made with the broad-
   casting system off to recover sorbent material.  It is
   assumed that 70 percent of the sorbent which was lost
   is recovered by this procedure.
                              69

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                        SECTION VII

  10,000 GALLON PER HOUR RECOVERY SYSTEM PRELIMINARY DESIGN

A preliminary design of a sorbent-oil recovery system for
use in unprotected waters was prepared based on the general
and specific design goals provided by the EPA.  These specific
design goals are given in Table 20.

                         TABLE 20

     Specific Design Goals for Unprotected Water System

Unprotected Waters

     a.  Environment

         Perform effectively in waters with up to 5-foot
         seas in combination with 30-mph winds and 2-knot
         currents,, close to shore in less than 80-foot
         depths.

     b.  Sorbent Recovery System

         The sorbent recovery system in combination with
         any necessary oil-water separation facilities shall
         have the capacity to recover at a minimum rate of
         10., 000 gal/hr of oil with 10 percent or less water
         content.

         (l)  The water content objective may be altered if
              this is consistent with the method of ultimate
              disposal of the oil.

         (2)  Oil-sorbent separation may be accomplished
              either as an inherent characteristic of the
              recovery device or an individual unit process.

         (3)  The device shall be capable of meeting the
              recovery rate objective while recovering oils
              with viscosities ranging from that of light
              diesel oil to Bunker C oil at 20 C.

         (4)  The thickness of the slick to be recovered at
              the specified rate shall be 1.5 mm or less.
                             71

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              TABLE 20 (Continued)

    (5)  The device may include as an integral part of
         the skimming process,,  a system of booms to
         aid in herding oil toward the harvesting de-
         vice.

    (6)  Design of units to be  temporarily attached to
         existing vessels must  consider transport needs
         and ease of installation with a minimum of
         special equipment.

c.  Oil-Sorbent Separation

    The unit must be capable of operating under hy-
    draulic loadings and ranges of oil concentrations
    consistent  with the performance of the oil har-
    vesting device.   It must be capable of producing
    output streams with the following characteristics:

    (l)  Oil -  10 percent water or less.

    (2)  Sorbent material - available for reuse or
         method for disposal.

    (3)  Water  - 10 mg/1 oil or less.

d.  Oil Storage or Disposal

    Specify floating or other appropriate land-based
    facilities  which.,  in combination with on-board
    storage, will have capacity to store material to
    be collected from spills of at least one million
    gallons. Agglomerates must be processed before
    land disposal to preclude leaching.   Other ap-
    propriate disposal techniques such as incineration
    will be considered as alternatives.
                        72

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                   TABLE 20 (Concluded)

     e.   Vessel

         The recovery system must be designed for either per-
         manent or temporary mounting on appropriate existing
         vessels.  The development of vessels designed specifi-
         cally for oil recovery use will not be considered.
         Vessels to be used must be capable of speeds of at
         least 12 knots under the environmental conditions
         listed above (however, not performing the oil re-
         covery function).  They must accommodate any required
         oil-sorbent separation equipment, the oil recovery
         device and, operating personnel, 24-hour fuel supply
         and all oil specified for storage on board.  They
         must be capable of speeds of at least 8 knots (how-
         ever not performing an oil recovery function) in
         10-foot seas and winds of up to 38 mph.
The system was designed to satisfy the required recovery rate
of 10,000 GPH of bunker "C" at 20 C.  The rationale for the
selection of the system operating parameters such as sweep
speed, sorbent coverage, and sorbent residence time are pre-
sented in Section V.  Many elements of the unprotected water
system are similar to those on the protected water system.
These are not presented in detail again so that reference
should be made to the appropriate parts of Section VI.

GENERAL DESCRIPTION

The basic sorbent recovery system consists of a pneumatic
broadcasting system with a moving parallel-plate nozzle,  a
harvesting conveyor, a transfer conveyor, a sorbent re-
generator, the necessary drive systems and a catamaran type
platform.  The basic characteristics of the unprotected water
(10,000 GPH) Sorbent-Oil recovery system are presented in
Table 21.  Figure 18 is an overall arrangement drawing of
this system.  The recovery equipment is mounted on a specifi-
cally designed platform rather than a vessel of opportunity.
The reasons for this form of mounting are presented in de-
tail in Section V.   Basically they are improved operating ef-
ficiency, reduced reaction time, and potentially lower life-
cycle cost.
                             73

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                         TABLE 21

           Characteristics of Unprotected Water
                Sorbent-Oil Recovered System
Design Oil Recovery Rate                10,000 gal/hr
Slick Thickness                         1.5 mm
Sweep Speed                             2.60 ft/sec
Sweep Width (Normal)                   32.0 ft
Sweep Width (Extension Booms)          64.0 ft
Active Length                          65.0 ft
Sorbent Material                   Open cell polyurethane foam
Sorbent Form                       Chips 3 in.X 3 in. xl/4 in.
                                       normal
Sorbent Pore Size
               Oil Viscosity < 1000 cps   80 PPI
               Oil Viscosity > 1000 cps   30 PPI
Sorbent Residence Time                    25 sec
Sorbent Coverage                          75 percent

                  Oil Recovery Performance
                   1.5 mm Slick Thickness


Oil Viscosity  Oil Recovery Rate Oil Recovery Water Recovery
    cps               GPH        from Slick        Rate
                                  percent           GPH

   <  6000          10,000          90              962
     10000           9,^50          85              844
     20000           8,600         77.5             752

           Oil Recovery for Viscosity < 6000 cps
Slick Thickness  Normal Sweep Width  With Extension Booms
      mm          (16 ft)  GPH        (64 ft)  GPH

      0.5                33°0               6700
      i.o                6700              13400
      1.5               10000              20000

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Ul
                                 STEAM GENERATOR
                       PUSHING      \     CONTROL STATION
                        BARGE        \     /     75 HORSEPOWER DIESEL
                                                                                     BROADCAST
                                                                                      NOZZLE
                                                \  HARVESTING CONVEYOR
                                                BROADCAST FAN
                                      SORBENT REGENERATOR
 TRANSFER
CONVEYOR
                                                                                            EXTENSION
                                                                                               BOOM
                                       AFT PONTOON
                                               FWD PONTOON
                                   FIGURE 18 - UNPROTECTED WATER RECOVERY SYSTEM ARRANGEMENT DRAWING

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RECOVERY SYSTEM COMPONENTS; BROADCASTING SYSTEM

The broadcasting system uses larger components but Is other-
wise similar in concept to the system on the protected water
unit.  Its technical and performance, characteristics are pre-
sented in Table 22.
                         TABLE 22

            Broadcasting System Characteristics
Sorbent Form

Sorbent Broadcasting Rate

Regenerated Sorbent Density
Broadcasting Nozzle Type
Nozzle Rate
Nozzle Angle
Nozzle Drive
Broadcasting Duct Diameter
Broadcasting Duct Length
Air Speed
Pan Type
Diameter (Wheel)
RPM
Pan Power (Total)
Transmission
Total Sorbent In System
Chips 3 in. X 3 In.x 1/4 in,
                    nominal
1.3 ft3/sec
1010 chips/sec
6.0 lbs/ft3
Moving Parallel Plate
0.. 5 cycle/sec
±50 degrees
Air Cylinder
21 In.
48.0 ft
45 ft/sec
American Blower Series 106
Industrial Fan Size 21
Long Shavings Wheel
36.5 in.
1099
36 HP
Mechanical
56 ft3
44,000 Chips
                     Sorbent Loss Rate
                Wind Speed
                    mph

                  0-10

                 10 - 20

                 20 - 30
      Loss Rate
       ft3/hr

        9.4
       47.2

       93.7
                               76

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Harvesting and Transfer Conveyors

The harvesting conveyor is mounted between the aft pontoons
of the recovery platform.  The overall width is 16 ft which
is made up of four 4-ft
-------
                          TABLE 24
              Transfer Conveyor Characteristics
  Conveyor Belt Width

  Conveyor Length

  Linear Belt Speed

  Belt Material


  Conveyor Support


  Drive


  Power
  Transmission
 3.0 ft

20.0 ft

 2.5 ft/sec
 3-Ply Stitched canvas
   Neoprene covered

 Troughed Bed* with integral
 takeup and drive pulley

 8 in.  diameter pulley-friction
 drive

 1 HP
 Hydraulic
  *  Hytrol Conveyor Company Model "TR" Horizontal Belt
     Conveyor or Equivalent
Sorbent Regenerator

The operating principles and basic configuration of the
sorbent regenerator for the unprotected water unit are
identical to the protected water unit.   These items are
discussed in detail in Section VI.  The belt width for the
unprotected water unit regenerator is 60 inches compared
with 24 inches for the protected water unit.  To limit the
increase in belt width in the unprotected water unit,  the
unit sorbent loading was increased from 0.22 ft3/ft2 to
0.3 ft3/ft2.  This slightly increases the density of the
regenerated sorbent but it remains at an acceptable value.
The development program reported in Appendix D covered
values in excess of 0.3 ft3/ft2 unit sorbent loading with-
out difficulties.  Table 25 presents the characteristics
of the resulting unit.
                              78

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                         TABLE 25

            Sorbent Regenerator Characteristics
Design Sorbent Rate
Belt Speed
Maximum Squeezing Force
Number of Squeezing Stations
Squeezing Roller Width
Squeezing Roller Diameter
•Lower Belt Material

Upper Belt Material
Power
•Transmission
-Air Supply
Squeezing Force
Squeezing Roller Travel
Beating
                      1,3 ft3/sec
                      1.0 ft/sec
                      220 Ib/in of belt-width
                      3
                      60 inches
                      6 inches
                      Steel Balanced Belting
                      Type B-60-32-4
                      Reinforced Neoprene
                      4 HP
                      Hydraulic Drive
                      Engine DrivenCompressor
                      Air Cylinder
                      4 in.
                      Heating Coils in
                        Collecting Pan
                      3000 Ib/hr steam
              Sorbent  Regeneration Performance
 Oil Viscosity
      cps

       2

    300

   1000

   4500

   20000
Sorbent
  PPI

   80

   80

   30

   30

   30
Squeezing Force  Regenerated  Sorbent
    Ib/in

     220

     220

     220

     220

     220
Density - Ib/ft1

      5.0
      6.0

      5.5
      6.0
      8.0
 Miscellaneous Equipment

 Additional components which should be included with the
 recovery system are an oil transfer pump with a capacity of
 500 GPM at 40 ft of head and a steam generator capable of
 evaporating 360 ga.l/hr at 120 psi.
                               79

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Power and Transmissions

The recovery system components are powered by a diesel
engine driving through a hydraulic or combination hydraulic
and mechanical transmission system.   The basic concept of
the power train is identical with that on the protected
water unit.  For this case, the engine is a 75 HP radiator-
cooled Model 3-53N Detroit Diesel or equal.  The broadcasting
system fan and the oil transfer and bilge pump can be driven
either by a direct mechanical or hydraulic system.  The
mechanical and hydraulic transmissions for the 10,000 GPH
systems are shown schematically in Figures 19 and 20, re-
spectively.  The mechanical system can be made to satisfy
the arrangement requirements and thus is recommended because
of its lower cost.  The sorbent regenerator,  the harvesting
conveyor and the transfer conveyor require a  hydraulic trans-
mission which is shown schematically in Figure 21.

RECOVERY PLATFORM

The recovery platform is based on a catamaran concept with
hulls consisting of four pontoons joined by trusses.  The
side trusses are screened to confine the sorbent material
and the aft pontoons are configured to herd the sorbent to
the harvesting conveyor.  The harvesting conveyor is mounted
between the aft pontoons.  Figure 18 presents an overall
arrangement of the recovery system equipment  and platform.
The basic characteristics of the recovery platforms are
presented in Table 26.

Hull

The hull configuration of pontoons joined by trusses was
selected for the following reason:

        Simpler to disassemble into units suitable for over
        road transport,

     -  Lower weight than conventional catamarans hulls,

        Satisfactory motions in the design sea conditions.

Appendix E presents the results of a 1/4-scale model test
of this platform concept.  These tests covered, sorbent
broadcast and recovery in calm water and waves, motions in
waves, and towing stability and resistance.
                              80

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          REDUCER
                     JJ-
          BILGE PUMP
                                           75 HP
                                          'DIESEL
                      t
                                              TO FAN
                                    'OIL TRANSFER PUMP
FIGURE 19 -
DIAGRAM OF FAN AND PUMP MECHANICAL TRANSMISSION
FOR 10,000  GPH  SYSTEM
                             81

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TYRONE 20450 PUMP
 65GPM @ 750 PSI
                                                                   BLOWER FAN
                                                                   TYRONE M25550
                                                                     MOTOR
                                                              TYRONE M20250
                                                                 MOTOR
             I		
          DELTA FLOW DIVIDER
         WITH SPECIAL 2:1 RATIO
                                                               BILGE PUMP
                                                              TYRONE M2-45
                                                                MOTOR
      FIGURE 20 - SCHEMATIC DIAGRAM OF FAN AND PUMP HYDRAULIC TRANSMISSION
                FOR 10,000 GPH SYSTEM
                                     82

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 TYRONE 20150 PUMP
20GPM@2500PSI
  DIESEL ENGINE
     75 H.P.
I	.
?

                                             I

                                             Hi-
                                                                     SORBENT
                                                                   REGENERATOR
                                                                      STAFFA B-30
                                                                       MOTOR
                                                                     400 Lb. Ft.@
                                                                     38-125 RPM
                                                                     HARVESTER
                                                                     STAFFA B-30
                                                                       MOTOR
                                                                    300 Lb. Ft.@
                                                                    75-150 RPM
                                                                      TRANSFER
                                                                     STAFFA B-30
                                                                       MOTOR
                                                                     36 Lb. Ft.@
                                                                     150-250 RPM
          FIGURE 21 - SCHEMATIC DIAGRAM OF SORBENT REGENERATOR AND CONVEYOR
                    HYDRAULIC TRANSMISSION FOR 10,OOOGPH SYSTEM
                                        83

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                         TABLE 26

     Unprotected Water System Platform Characteristics
Platform Concept
Overall Length
Overall Beam (Normal)
Overall Beam (Extension Booms)
   Draft (Maximum).
   Hull Beam (Maximum)
   Hull Depth
   Hull Structure
   Light Ship Weight
   Service Loads
   Recovered Fluid (10,000 gals)

   Full Load Condition
   Deployment Draft
   Full Load Draft
   Propulsion
   Deployment Speed
   Onboard Chip Storage
                      Catamaran
                      82.0 ft
                      32.67 ft
                      64.0 ft
                       4.5 ft
                       3.5 ft
                       8.5 ft
                      Aluminum
                      29,065 Ibs
                      2360 Ibs
                      75.000 Ibs

                     106,425 Ibs
                      1.25. ft
                      4.5 ft

                      10 knots
                      500 ft3
     [tern
                 Shipping Characteristics
Length
  ft
Width
  ft
Height
  ft
Weight
  Ibs
Aft Pontoon    24.0       8.5

Fwd Pontoon    12.0       3*5

Fwd Beam       27.0       2.08

Side Beams     27.0       8.0


Aft Beams      16.0       7-0
                       8-5       3950 (each of 2)
                       8.5       1400 (each of 2)
                       2.0       1420
                       8.0       1250 (largest
                                        of 4)
                       7.5       1200 Ibs
                              84

-------
The hull and  truss  structure can be either  aluminum or steel
Aluminum has  a  lower  weight  for  greater  onboard oil storage
and easier  shipping.   A  steel hull  will  have a lower initial
cost and higher weight.   The characteristics presented in
Table 26 are  based  on aluminum construction.  The recovery
platform can  be fitted with  extension  booms to increase the
sweep width thus  increasing  oil  recovery rate in thin slicks
Typical extension booms  are  shown in Figure 18   It is ex-'
pected that these booms  could be used  only  in relatively
calm water.

Propulsion

The unprotected water recovery system  is not self propelled.
It may be either  towed or pushed by a  vessel of opportunity'
or a barge.   Figure 18 illustrates  how the  system can be
pushed by a barge.  The  recovered oil  can then be pumped
directly into the barge.

Outfit

In order to make  the-recovery platform an operational sys-,
tern., a certain  amount of outfit  is  required.  The typical
outfit items  are  listed  in. Table 27.

                          TABLE 27
          Unprotected Water  System  Outfit Items
          Railings
          Hatches
          Anchors and Lines
          Fenders
          Fire Extinguishers
          Lights
          Lockers
Chocks and cleats
Piping
Radio
Chemical Toilet
Operators Stand
Miscellaneous
Weight Summary
A detailed weight estimate was prepared for the unprotected
water recovery system and is presented in Table 28.  This
weight estimate is based on aluminum construction.  If steel
structures were used,, the total structural weight would in-
crease to about 45,500 pounds.  This would reduce the amount
of recovered oil which could be carried on a draft of 4.5 ft
to about 6400 gallons.
                              85

-------
                                                                      TABLE  26
                         CALCULATION OF WEIGHT
Weight Estimate for  10,000  GPH Unprotected
     Water Sor^-ent^OH Recovery System
CD
                                                                                                                  1 of
*"* UriDrotectel Water Recovery Unit
ITEM Structure - A'utninum
Aft Pontoons
r'.25 in. plate an-1
3 in. •.: 1 in. x 0.25 in. an:;le on 15 in.
centers .
Outroar-; Si-ea
Inr. oar;: Si::es
Transom
Bov: 'Plate
Deck an:! B •ttom
Bulk'neals
Lon.jitu "inal '.;evs
Fopvar ":
Pontoons
Outboard ~i:~es
Inboarii sides
Bo:.'
Aft Enri
Deck ano Bottom
Bulkhea-
Longituiinal v/ebs



•
•ait 1 mmm*
•EIGHT IN
counts




172S
1152
576
5]>
liiiiC
576
?83


792
643
^02
202
216
17^
105


&907

ABOVE M.D BASF LIME
C.6.
























VERT. MOM.
























mrEBRto TO; Transom
C.G.




12. C
5.c
C
20. C
10.1
LI. "
L6. 0


rs.5
r5.5
Bl
n
^6
76
76
••



m> MOMENTS
























OltfRM
C.6.
























•FTER MOMENTS
























WIN SIMS

-------
CD
                        CALCULATION OF WEIGHT
                                                                TABLE 28  (Continued
                                                                                                                   2  of 5
*"* Ooen Water
ITEM

Forvard Beam

Side Beams
Upper Longitudinal Tubes
Lower Tubes
Vertical an3 Transvsrse Struts
	 , 	 ' ? .-< * * 7 	 : 	
2>-;4x8
2 x 7 -r. .'4
Diagonals 2. x 5 x in
2 x 5 x 12
2x7x8
	 — 	 __ . . — f — L ._ 	 _ 	 	 i __. . .. j. • _ _ — -- . - — 	
Aft Beam
3 x 16
4 x 5 x ^ x 7
" 6 x 6 x ^ x c

GratinR Aft If y 6
Sid^s. 2 x. 51 :: 5
Sub Total
Margin 20 percent
Total Structure
j™
•€IWT I*
ooun 3 s

118S


•519
n37

17'5
202 .
176
*H7
373
353

2l(.o
151
321

?SO
1377
15220
,3044
18254
ABOVE M.D BASF LINE
C.G.






















VERT. MOM.











^W^^^^B^HWOB-IKWWM.-










RErEmo TO; Transom
C.G.

72


45. c
^5.^

47
^••riw^MHVfri
47
47
Ly
-7
7

.0
.0
.0

.0
3.C
4'. 5

4-.=S
rm P40MENT5




















525324

630380
OUfRHI
C.6























ArTEKMOMtNTf












p^M*MH«VHM^H^^MM»a^*










W ttDU

-------
                                                           TABLE 28 (Continued)
00
oo
                        CALCULATION OF WEIGHT
                                                                                                                   3 of 5
SHIP Opfp. Water
ITEM fV. £,!,-„ I <-.- 1 q '



Hull Outfit fn i Krrvi n -' rv n •;
RalUn-v:
Hatclior,
Anchors an 1 Lino
Fv.Tr".c-r~
Firt K:> i < r-.^i'i "ber
Lights
Loclcer-R
Chocka arri Clrats
Misccllancouc
Piping
Radio
Chemical Toilet.
Operators St?jn'l.
SuV-Total
Margin ?0 prrcent
Total Hull Outfit




Mn vmm
WEIGHT IN

8000


3 '10
-AO
160
300
?co
50
50
75
100
?50
30
50
ii-^O
?3?5
Ji75
?800




ADOVC k«.D BASF LINE
C.G.
























VERT. MW.
























REFEBREO TO-. Transom
c.c.

3.5


;6
il5
T"
i-i
LO
50
'0
!0
?0
10
30
PC
?0
37.-.

37.^




FWO MOMENTS

63,coo















fi^OP

76C3C




Ollf'U
C.G.
























ArHR MOMENTS
























M1N SIOKS

-------
                                                           TABLE  '-'8  (Continued)
                        CALCULATION OF WEIGHT
                                                                                                                   of 5
00
VD
s"" Open Wstrr
i™" Lori is


Diese] Fuel
Personnel fin-1 Kf c\ elF
Sorhmt
WTcfr
Torai










i
i
i
i
i



Mtt 1 opwrOJI
HEIGHT IN
PQ unrig


!! 00
';CO
1?CO
16C
03 -..-^

















ABOVE M.O OAsr LINE
C.G.
























VERT. MCM.
























Hereunto to. Transom-
C.G.


10
10
10
10
10

















FWO MOMENTS


;l 000
C>CCQ
1PCOO
l^CC
•p--^ro

.















O«E^|IM
C.G.
























AFTER MOMENTS
























•om SIDU

-------
                                                                   TABLE 23 (Conclude:!}
O
                           CALCULATION OF WEIGHT
                                                                                                                        5 of 5
sx" Ooen Wati'r
ITtM Summar;/

Structure - A"1. ur.npuin
yr-ehanlcal Systems
Outfit1 - -.•••-
-
Ll^ht S'-i-ir)

Load's

Service Condition

Recovc-r'3 ."• Oil

Full Loa:i Draft - ;) ft x '^ in.










MR I COMPUTOA
•EIGMT IN
.pounds

KS?'-t
5, CCO
?',600

?PJ c6;i

?, V5o

31','i24
-
75/000

1 ^ri 'i-i'1
L w< ' . A ^.










ABOVE MtO BASF i. (NE
C.G.
























VERT. MCM,



>





-














REFESHEO TO: fp ,, ^ ^ r- Q n
C.G.

; •" • 5-
-;i . 5
•;1Y./-

?..; -

"^ O
. ^.' • w

?c; 7-
'- */ • j

^.'75

17. :










FWD MOWCNTS
-.
o.=-C -3-;
65COC
Vf'p.Ap
i - ^ -• ^

77'<-:69 "

2 \-': C 0

7?^C(;S

.,1.06, 55,

L,ccli,3ic










O4Ct;ufl
C.G.
























AFTER MOMCNTS













•










•om *iou

-------
CREW AND OPERATING PROCEDURES

The unprotected water sorbent-oil recovery system should be
operated by a four man crew consisting of a captain,  engineer
and two deck hands.  The duties of these crew members are
similar to those assigned to the crew of the protected water
system which are detailed in Section VI.  The operating pro-
cedures for the unprotected water system are similar to those
for the protected water system.  The major difference  is
that the unprotected water system is not self propelled.  It
can be either towed or pushed by a vessel of opportunity.  A
particularly favorable procedure would be to have the re-
covery system pushed by a tank barge.  The recovered oil
could then be pumped directly to the barge, as mentioned pre-
viously.

COST ANALYSIS

An analysis was made of the construction and operating costs
of the 10,000 GPH unprotected water recovery system.   The
assumptions and methods used in this analysis are identical
to those used for the protected water system and are pre-
sented in detail in Section VI.

The construction cost will depend on the structural material
and the extent of the outfit.  The selection of these items
depends on the intended duty and the importance of initial
cost.  The construction cost data are thus presented in
Table 29 for the various system elements.  Various possible
cost options are presented in Table 30 ranging from minimum
initial cost to the complete system.  The recovery machinery
is common to all cases and is the heart of the system.  As
a result, a detailed analysis of the recovery machinery con-
struction cost estimate is given in Table 31.

The direct operating costs were estimated on a per hour of
effective oil recovery basis and are presented in Table 32.
The charter rates for the tugboat and barge, if used, are
subject to wide variations depending on the exact situation.

-------
            TABLE 29

Unprotected Water Recovery System
          Cost Analysis
Summary
ftecovery Unit - In
Stalled and operating
Combined mechanical and
Hydraulic
full Hydraulic Drive
Htm - Steel
- Steel with inor-
ganic zinc
coating
- Aluminum
Olitfit - Minimum - Steel
- Aluminum
- Complete - Steel
- Aluminum
Supply of Sorbent
Material
.!,£ J . :l J .
Dollar Total for 1
Materials



20060.
224<">0.
20700.

26500.
49700.
3850.
"150.
12300.
17040.
4600.
MH



666.
670.
-

-
-
382
38?
448
4^8
-
Total



28060.
30500.
20700.

26500.
49700.
8430.
8730.
17r'80.
2174Q.
4600.
Dollar Total ea. of 3
Material



17,660.
18,770.
18,630.

23,850.
44,730.
3390.
3650.
10,810.
15,000.
4600.
MH



585.
589.
-

_
-
336
336
394
394
-
Total



24,680.
26,840.
18,630.

23,850.
44,730.
7420.
7680.
15,540.
19,730.
4600.
               92

-------
            TABLE 30

Unprotected Water Recovery System
    Total Construction Costs

Minimum Initial Cost
Recovery Unit - combined
mechanical and Hydraulic
Steel Hull
Outfit (Minimum)
Total w/o Sorbent
Material
t
Supply of Sorbent Material
Total with Sorbent Material
Continuous Duty
1 	 ~~
j Recovery Unit - Combined
Mechanical and Hydraulic
Aluminum Hull
Outfit (Complete'!
Total w/o Sorbent Material
Supply of Sorbent Material
Total with Sorbent Material
_____ — — — — — — — — — — — — — — — — — —
Dollar Total
for 1
28060.
20700.
8430.
57190.

4600.
61790.
28060.
49700.
21740.
995CC.
4600.
1CIL10C.
„. — _—— — — — — — —
Dollar Total
each of 3 :
24680.
18630.
7420.
50730.

4600.
55330.
24680.
44730.
19730V
89140..,. .
4600.
93740.
	 • • 	 '
                 93

-------
                         TABLE 31
              Unprotected Water Recovery Unit
                  Recovery Machinery Cost
Oil Recovery Machinery

Sorbent Regenerator
     Fan
     Harvesting Conveyor
     Broadcast Duct
     Broadcast Nozzle
     Transfer Conveyor
     Hydraulic Drive
     Mechanical Drive
     Diesel
     Transfer Pump

     Total for 1
     Total each 'of 3 at .88

     Added for full hydraulic drive
     Total for 1
     Total each of 3 at .88

Installation and Debug system
     (Hydraulic and Mechanical)
     Total for 1
     Total each of 3 at .88
     (Full hydraulic system)
       Total for 1
       Total for each of 3 at .88

Total Labor to Fabricate and Install
     (Hydraulic and Mechanical Drive)
       Total for 1
       Total each of 3
     (Full' Hydraulic System)
       Total for 1
       Total each of 3
Dollar Total
  for 1

   5242.
   1000.
   2800.
    750.
    100.
   1600.
   4920.
    800.
   2720.
    130.


 20,000
 17,655

   2400
 22,462
 19,767
Man Hours
  315

  150

   24
   16
   88
   12
   40
  330
  290

   60
  390
  3^3
               336
               295

               280
               246
               666
               585

               670
               589

-------
                              TABLE 32
      Unprotected Water Recovery System Direct Operating Costs!
     Per Hour of Effective .011 Recovery1
               Crew                          $40.00
               Maintenance                    10.00
               Sorbent                       435.00
               Fuel and Miscellaneous         10.00
               Tug Boat                       62.50
               Barge                          20.00
                 Total                      $577-50

     70 Percent Lost Sorbent Recovery on Second Sweep2
               Crew                          $80.00
               Maintenance                    20.00
               Sorbent                       130.50
               Fuel and Miscellaneous         15.00
               Tugboat                       125.00
               Barge                          20.00
                 Total                      $390.50
1  No attempt is made to recover sorbent material lost due  to
   winds.
2  A second sweep of the slick area is made with the broad-
   casting system off to recover sorbent material.   It is
   assumed that 70 percent of the sorbent which was lost is
   recovered by this procedure.
                              95

-------
                        SECTION VIII

                       ACKNOWLEDGMENTS

This project was carried out by a team of HYDRONAUTICS,
Incorporated personnel headed by Mr. E. R. Miller, Jr. and
Dr.  A.  Gollan and including Mr. L. Stephens, Mr. J. Ricklis,
Mr.  H.  Lain and Mr. H. Cartright.  Mr. ¥. Lindenmuth also
contributed to the development of the initial concept.  Mr.
K. Jakobson acted as the project officer for the Environmental
Protection Agency.
                               97

-------
                       SECTION IX

                       REFERENCES


1.    Witmer,  Dr.  F.  E.,  and Gollan,  Dr. A., "Final Report
     of Phase 1 Development Program of a Continuous Re-
     generating Moving Bed to Remove Oil from Oil-Water
     Suspensions/' HYDRONAUTICS, Incorporated Technical
     Report 7080-1 (in preparation).

2.    Buffalo Forge Company,, "Fan Engineering/1 Buffalo
     Forge Company,  1961.
                              99

-------
                         SECTION X
                         APPENDICES
                                                      Page
A.   Characterization of the Sorbent Material	  103
B.   Development of the Sorbent Broadcasting System...f  117
C.   Development of the Harvesting Conveyor and
    Overall Oil Recovery Performance	'  145
D.   Sorbent Regeneration System Development	,  l6l
E.   Model Test of a 1/4-Scale Model Recovery
    Platform	f  173
                              101

-------
                         APPENDIX A

            CHARACTERIZATION OP THE SORBENT MATERIAL

The objective of this task was to generate data on the oil
absorption capabilities of the sorbent material as a function
of sorbent characteristics, oil characteristics,, slick thick-
ness and residence time on the slick.  The sorbent material
selected for use in the oil sorbent recovery system was open-
cell reticulated polyurethane foam made by the Scott Paper
Company.

The data were obtained from the tests of almost 900 in-
dividually tested polyurethane chips.  Test conditions in-
cluded the following parameters:
          Slick thickness

          Slick temperature

          Matrix porosity


          Matrix reusability


          Media geometry
          Residence times of media
                     in slick

          Four types of oils:
0-5
       - 3-5 mm
4 - 27°C

30, 60, 80,  100,  (Mostly
30 and 80 ppi )

Fresh and regenerated
(Mostly regenerated)

Square and rectangular
0 - 60 sec (Mostly 5,
10, 15, 30 sec)
Diesel, No.  4,  Crude,
Bunker "C"
The first tests were scouting tests, after which the tests
where standardized in the following way.  Only regenerated
sorbent material was used since this represents the real
case.  The scouting tests revealed that there were no dif-
ferences in absorption rates or absorbed quantities between
fresh and regenerated polyurethane chips.  According to data
reported in Reference 1, absorption of heavy oils proceeded
at a lower rate in the 100 ppi grade, then in the smaller
ppi grades, while the lighter oils did not indicate a basic
change between 100 and 80 ppi.  For this reason tests were
carried out on 80 and 30 ppi grades only.
                              103

-------
Although a range of residence times of the chips on the oil
slick between 0 and 60 seconds were considered for testing,
it was decided after the scouting tests that enough oil
would be absorbed into the chip in periods shorter than 60
seconds to justify a reduction in absorption time.  There-
fore, tests were conducted with absorption times of 5* 10,
15 and 30 seconds.   Drain time was fixed at 10 seconds, which
was the estimated elapsed time between lifting the chip out
of the slick and regenerating it.

Each combination of variables was checked by three different
chips.  Average results obtained from sets of three chips
were used for calculating absorption.  A standard measure of
absorption was utilized throughout the tests; i.e., absorption
ratio.  This is the ratio, expressed in percent, of the weight
of oil absorbed by a certain chip, to the weight of the oil
directly underneath this chip.  These data are best presented
by plotting the absorption ratio as a function of the oil
viscosity, using slick thickness, and absorption times as
parameters.  Viscosities and specific gravities of the oils
used, were measured within the range of 1-30°C.

Figure 22 presents  viscosity data for the four types of oils,
as determined by England Laboratories of Beltsville, Maryland.
Figure 23 presents  specific gravity data as determined in the
laboratory at HYDRONAUTICS, Incorporated.

The data are presented in Figures 24 through 30.  It was
found to be very difficult and time-consuming to produce an
oil slick having an exact selected thickness.  Thus, the
data, which were distributed throughout the thickness range,
have arbitrarily been divided into three groups:  0-1; 1-2;
2-3-5 mm.  Data from each group were plotted separately-using
absorption time as  the parameter.  Figures 24 through 26
present data for 30 ppi grade polyurethane foam and Figures
27 through 29 present data for 80 ppi grade.  Figure 30 is
an example of the data for one specific absorption time -
15 seconds.  Although the data show some scatter, there still
is an unmistakable trend which indicates less viscous oils,
(Crude, No. 4 and diesel) are absorbed much better than the
viscous Bunker "C"  oil.  Also the curves indicate that the
absorption ratios are improved as absorption times are in-
creased.  It was noticed that more oil, especially in the
lighter oils  group, was lost during the drain period from
the 80 ppi grade.  This phenomenon is shown in Figure 26,


                              104

-------
  100,000
   10,000 h-
o
     1000 t-
                                                      A  BUNKER C
                                                      D  CRUDE
                                                      O  |4 OIL
                                                      O  DIESEL
                                   TEMPERATURE  C

             FIGURE 22 - VISCOSITIES OF OILS AS A FUNCTION OF TEMPERATURE
                                  105

-------
£

I
O
u
O
LU
o.
   0.96
   0.94
   0.92
   0.90
0.88
   0.86
   0.84
   0.82
   0.80
                                     D
                                              A   BUNKER "C"
                                              O   DIESEL
                                              D   CRUDE OIL
                                              O   #4 FUEL OIL
                             10         15

                                 TEMPERATURE °C
                                                20     23  25
30
      FIGURE 23 - SPECIFIC GRAVITIES OF OILS AS A FUNCTION OF TEMPERATURE
                                   106

-------
                       280
H
O
                                                                                                          POLYURETHANE FOAM
                                                                                                          POROSITY - 30 ppi
                                                                                                          SLICK THICKNESS 0 - 1 mm
                                                                                                          O  5 sec
                                                                                                          O  10 sec
                                                                                                          O  15 sec
                                                                                                          A  30 sec
                                                                                          1000
10,000
                                                                    KINEMATIC VISCOSITY cm /sec


                                               FIGURE 24 - EFFECT OF VISCOSITY AND RESIDENCE TIME ON OIL ABSORPTION
100,000

-------
    280
   240
    200
O
2   160
Z
O
    120
     100
                                               POLYURETHANE  FOAM
                                               POROSITY - 30 ppi
                                               SLICK THICKNESS 1 -2mm
                                               O  5 sec
                                               O 10 sec
                                               O 15 sec
                                               A 30 sec
                                                                                           co
                                                                                           O
     40
                  DIESEL
CRUDE
                                                                                              /»ec

                          FIGURE 25 - EFFECT OF VISCOSITY AND RESIDENCE TIME ON OIL ABSORPTION
100,000

-------
    280
    240
    200
2   160
i
z
o
03
<
    120
     100
     80
      40
                      i     r
                  DIESEL
                             10
CRUDE
          100
                                                      T
                                               POLYURETHANE FOAM
                                               POROSITY -  30 ppi
                                               SLICK THICKNESS 2 - mm
                                               O  5 sec
                                               D 10 sec
                                               O 15 sec
                                               A 30 sec
           BUNKER "C"
1000
10,000
                                                 KINEMATIC VISCOSITY cm /sec

                                FIGURE 26- EFFECT OF VISCOSITY AND  RESIDENCE TIME ON OIL ABSORPTION
                                          100,000

-------
280
                                                                                          r	1
                                                                                   3" x 3" x 3/8" SQUARE
                                                                                   POLYURETHANE FOAM
                                                                                   POROSITY - SOppi
                                                                                   SLICK THICKNESS 0 - 1mm
                                                                                   O  5 sec
                                                                                   O  10 sec
                           OIL RECOVERED
ABSORPTION RATIO =
                    VOLUME OF OIL BENEATH FOAM
                         10
                                100                  1000

                               KINEMATIC VISCOSITY cm2/sec
10,000
                                                                                                                                  O
                                                                                                                                  H
                                                                                                                                  H
100,000
                       FIGURE 27- EFFECT OF VISCOSITY AND RESIDENCE TIME ON  OIL ABSORPTION

-------
280
                                                                                   POLYURETHANE FOAM
                                                                                   POROSITY - 80 ppi
                                                                                   SLICK THICKNESS 1 - 2mm
                                                                                   O 5 sec
                                                                                      10 sec
                                                                                   O 15 sec
                                                                                   A 30 sec
                                                                   1000
                                            KINEMATIC VISCOSITY crn/sec
10,000
100,000
                       FIGURE 28 - EFFECT OF VISCOSITY AND, RESIDENCE TIME ON OIL ABSORPTION

-------
280
                                                                                   POLYURETHANE FOAM
                                                                                   POROSITY - 80 ppi
                                                                                   SLICK THICKNESS 2 - 3.5
                                                                                   O 5 sec
                                                                                   D 10 sec
                                                                                   O 15 sec
                                                                                   A 30 sec
                                                                    1000

                                             KINEMATIC VISCOSITY cm2/sec
10,000
                                                                                                                                   CVI
100,000
                           FIGURE 29 - EFFECT OF VISCOSITY AND RESIDENCE TIME ON OIL ABSORPTION

-------
280
240  —
200  —
o


!<   160



z

o

I—
a.
IX.


8   120
CO




    100





     80
  40
                  D1


                 O
                 a


                 o
               DIESEL
                          10
                                              O



                                              D
                                         CRUDE
                                                   100
                                                               1	T
                                                                                         i—r
                                                                                                TIME - 15 sec


                                                                                                80 ppi

                                                                                                O 0-lmm

                                                                                                D l-2mm

                                                                                                O2- mm
                                                                                        Oo  v

                                                                                         O    CO
          BUNKER "C"
1000
10,000
                                              KINEMATIC VISCOSITY cm /sec




                                FIGURE 30 - EFFECT OF VISCOSITY ON OIL ABSORPTION
                                                                                                                100,000

-------
where absorption ratios dropped as the viscosity was reduced,
rather than following the increasing trend shown on the other .:
figures.  It is also shown on Figure 24 where the points
which represent some diesel oil experiments are very low,
again becaus.e of rapid draining from the, more open structure
of the 30 ppi grade.  This phenomenon had a much smaller ef-
fect on the results of the 80 ppi, grade.

No drastic differences were noticed between absorption ratios
from slicks of different thicknesses which actually means
that absorption rates are affected by the oil slick thickness
and are increased as the thickness is increased.  The following
table presents absorption influxes for an imaginary oil, having
a kinematic viscosity of 100 cm2/sec, and a specific gravity
of .9 gr/cm3.   The fluxes were calculated for 30 seconds  of
absorption, where absorption values were picked from the
curves of Figures 24 through 29-

                          TABLE 33

                    Oil Absorption Fluxes
Sorbent Type
PPI
30
30
30
80
80
80
Slick Thickness
mm
1
2
3
1
2
3
Absorption Influx*
gr/s ec cm2
5.35*
10.35*
10.80*
4.50*
9.10*
14.78*
lO-3
. ID"3
ID'3
ID'3
lO-3
lO"3
* Area of chip -
103.5 cm2
  Except from the flux in the 3 mm 30 ppi case which is low
  in comparison because of higher drainage,  the fluxes in-
  crease almost linearly with the slick thickness.
                             114

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Based on the results of this task it has been concluded that
80 ppi polyurethane foam should be used as the sorbent ma-
terial for low viscosity oils.  Either grade may be used on
high viscosity oils such as Bunker "C".  The figures re-
lating the absorption ratio to the parameters of oil vis-
cosity, slick thickness, residence time and foam porosity
may be used in engineering estimates of sorbent coverage
required for complete removal or the oil recovered with 100
percent coverage.
                              115

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                        APPENDIX B

      DEVELOPMENT OF THE SORBENT BROADCASTING SYSTEM


The objectives of this task were:

     (l)  Develop   and   demonstrate a means of distributing
          sorbent material chips, on an oil slick, more or
          less evenly across the inner width of the craft at
          its forward end.

     (2)  Develop and demonstrate a pneumatic system for
          conveying  chips from the oil removal section of
          the craft to the distribution device.

These objectives were accomplished with model tests.  Due
to the specialized nature of the problem, the model size and
other parameters were near full scale to reduce scaling
problems In the prototype design stage.  The resulting design
information Is thus limited to craft employing the same basic
concepts and of the same order of size and capacities as the
model.

Before selecting basic parameters for the model, a small
scale experiment was conducted to examine basic questions.
At that time the intent was established to conduct most of
the experiments with a material having greater density than
the candidate material.  This was done to simulate the weight
effects of retained oil in regenerated chips while avoiding
the problems associated with handling regenerated chips.
Only those tests necessary to check for possible problems
associated with oily material were conducted with regenerated
chips.  This approach was taken based on experience gained
in previous work with the sorbent material.  Indications
were that the porous and fibrous surface of the material did
not permit large areas to come Into contact and it was felt
that stickiness would not be a problem.  Weight Is of course
a consideration in conveying and even the small amount of oil
retained in a thoroughly squeezed chip is enough to increase
its weight by a factor of two.

Closed cell polyurethane foam, available in a non-rigid form
and with a density about twice that of the candidate material,
was used for most of the testing.
                             11?

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STAGES IN THE DEVELOPMENT OF THE DISTRIBUTION DEVICE

Passive Nozzle Developed on Small Scale Experiment

The small scale experiment produced a passive distribution
nozzle in the form of a transition .from a circular duct to
a wide, • shallow, rectangular outlet.  Thus in the horizontal
plane, diffusion occurred, supplying width to the sorbent
distribution-pattern.  The length of the nozzle was minimized
and .internal vanes were installed to reduce the effective dif-
fusion ; angle.. .•      ..        ;,;.,..,
          j  . .     „
There was concern that the leading edges of these vanes might
trap sorbent chips if the chips were excessively "sheet-like";
that is,  thin for a given set of outline dimensions.   This
did in fact occur but it appeared that for 3-inch square
chips  (candidate size for full scale) a 3/8-lnch thickness
provided enough stiffness so that chips would not fold com-
pletely over the leading edges and be permanently trapped.

Further,  it was felt that if the dimensions between leading
edges were kept large relative to chip dimensions,  it would
not matter if some chips were trapped.

Passive Nozzle Tested on the Full-Scale Model

A similar nozzle for the full-scale model was designed and
fabricated of sheet metal.  Vanes were of cardboard,,  tem-
porarily taped in place since some trial and error was ex-
pected in determining their location (Figure 31).

This nozzle performed quite well in early tests when ma-
terial feed rates were still relatively low.  Distribution
patterns  were sufficiently wide and,fairly even  (Figure 31).
At rates  above about 25 percent, however, the nozzle became
plugged with chips at the vanes leading edges.

Passive External Plate Distribution Device

It was not certain whether the plugging was caused by higher
chip concentration or the reduced speeds which are a con-
sequence  of increased chip rate.  It was thought that the
conditions which precipitated a plug might be temporary and
that if they did not occur in a closed area, a plug might
not fully develop.   Based on this reasoning, a distribution
                             118

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                              ~   "

FIGURE 31 - CHIP BROADCAST PATTERN ACHIEVED IN EARLY TEST
           (Grid Spacing = 4 feet)
                           119

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device was constructed which was essentially an open nozzle.
Splitter plates were located several inches away from the
conveying duct outlet.  The plates were less efficient than
the nozzle at directing flow to the sides,  but with leading
edges located external to the duct,  it was  hoped a  complete
plug would be unable to develop.

Higher chip rates were obtained with this  concept (about
50 percent) but eventually, plugs did occur unless  the
plates were moved so far away from the outlet that  distribu-
tion became unsatisfactory.  In fact,  distribution  patterns
were never completely acceptable with the  external  device
even at low chip rates.

Flexible Ducting Nozzle

Failure to achieve adequate chip rates with a passive nozzle
forced a decision to accept the penalties  associated with an
active distribution device.  It is conceivable that a thicker,
stiffer chip would have been compatible with a passive noz-
zle but the extra material would be wasted  in terms of oil
recovery and impose acquisition and storage penalties.

The first approach to an active distribution device employed
a section of flexible ducting attached to  the conveyor out-
let.  The open end of the flexible section  was free to swivel
^5 degrees to each side about a vertical axis.  This was a
mechanically and structurally neat installation but it failed
by plugging.  The ducting was inexpensive,  fabric covered,
coiled wire construction, and it is felt the plugging began
in the ridges on the compressed side of the duct in the fully
deflected position.

Movable Parallel Plate Nozzle

In the meantime, while awaiting delivery of the flexible
duct, another concept was developed and tested with more
success.  Two rectangular plates were hinged at the vertical
edges of a rectangular outlet section.  Their free  ends were
connected with a link.  A horizontal plate  was mounted above
and below this movable plate unit.  The result was  a 2-foot-
long, rectangular cross section portion of  duct which could
swivel JI5 degrees to either side of center.  The geometry
is such that cross sectional area is a minimum at the sides
and the increased outlet speed is beneficial In obtaining
lateral throw.

                             120

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This device was capable of passing chips at the highest rates
achievable with the existing chip feeder box.  A plug did de-
velop in one test at high chip rates.  It occurred in the
sharp corner produced when the nozzle is fully deflected. The
sharpness of the turn will be reduced on the prototype design.

EXPERIMENTAL EVALUATION OP SELECTED DISTRIBUTION DEVICE
(MOVABLE PARALLEL PLATE NOZZLE)

Description of the Model and Experiment

Figure 32 shows the nozzle installed on the full-size model
of the broadcast system.  The forward structure of a con-
ceptual craft was also simulated.  The flotation pontoon
walls act as windbreaks as well as chip containment devices.
The forward portion of the side screens serve a containment
function and the simulated debris rake serves a certain con-
tainment role since its members must be large enough to pro-
vide significant strength on a prototype.  The nozzle move-
ment, which would be powered on a prototype, was performed
by hand in the experiment.

Broadcast distributions were defined by determining the
number of chips deposited in each of eight, 4-foot-wide strips
running parallel to the model centerline.  This method was
satisfactory for winds less than about 8 mph.  In higher
winds, chips would not stay fixed on the grass surface of the
test area and quantitative measurements could not be made.
Data are available only in the form of photographs taken during
and immediately after these tests.

Broadcast Patterns Calm and Light Winds

Quantitative broadcast pattern data are presented in a
manner showing deviation from the optimum, which is an equal
number of chips in each longitudinal strip.  Some data from
the external plate device are presented in Figure 33 to il-
lustrate its ineffectiveness in producing uniform distribu-
tion.  Results for the selected nozzle concept are shown in
Figure 34.

Some of these tests were conducted in winds up to about
6 mph at 30 to 40 degrees off the bow and it appears that
irregularities in nozzle motion and chip rate have more ef-
fect on distribution than winds of this strength.
                              121

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      I I>

FIGURE 32 - SIMULATED DEBRIS RAKE, FLOTATION PODS, AND
           SIDE SCREENS ERECTED AT DISCHARGE END OF
           BROADCAST EXPERIMENT
                         122

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                                    PLAN VIEW Of
                                    SPLITTER PLATE
                                    ARRANGEMENT
 FIGURE 33- CHIP DISTRIBUTIONS OBTAINED WITH PASSIVE EXTERNAL
           PLATE DEVICE
                            123

-------
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   FIGURE  14  - CHIP DISTRIBUTIONS OBTAINED WITH
               MECHANICAL NOZZLE. (Wind from calm
               to 6 mph at 30 degrees off the bow)

-------
The data show that if nozzle motion  is  slowed near  the sides,
distribution satisfactorily close  to uniform can be achieved'
in cross winds up to about 6 mph.,  If the wind is nearly on
the bow., distribution should remain  satisfactory in con-
siderably stronger conditions.

Strong ¥ind Patterns

Strong crosswinds had a pronounced effect on distribution
patterns.  An examination of photographs taken of tests con-
ducted in 14 and 20 mph winds  at 45  to  60 degrees off the
bow indicate distributions similar to that  shown in Fig-
ure 35.  Winds from this direction probably .have more effect
than head or beam winds.  Head'winds,, of course,, produce no
asymmetry,, and crosswinds are  more effectively blocked by
the pontoon sidewalls.

The non-uniformity in broadcast patterns caused by winds is
not an easy problem to attack  since  any structure added as a
shield carries its own penalties.  The  best approach may be
to provide for manual control  of the nozzle motionVand use
this means to achieve best possible  slick coverage in strong
winds.

Sorbent  Loss Rates

Some sorbent material will be  lost in operation and the
magnitude of the losses must not be  unreasonable in terms
of sorbent material make-up capacity.   In all broadcast tests
conducted in conjunction with  the  simulated bow, the number
of sorbent chips deposited outside of the enclosure was de-
termined (chips thrown through the debris rake were not con-
sidered  lost unless deposited  outside of the projected line
of the pontoon wall).  These losses  are presented in Table
34 as a  percentage of total chips  broadcast in each test.
Except for tests 47 and 52, a  conservative  average loss rate
is about 2 .percent.    ";.•  •  • • '      '

Tests 47 and 52 are considered:unrealistic  compared to the
prototype counterpart for a combination of  reasons.  Chip
rates were low and because of  the  high  speeds associated
with low rates, chips were thrown  a  maximum distance.  High
speed alone does not produce loss  but for these tests, the
nozzle was mounted horizontally for  convenience of assembly.
                              125

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                       TABLE 34
          Sorbent  Chip Loss Rates Experienced
               in  Full-Scale Model Tests
Test No.
45
46


48
49
50
51
52

53
¥ind
Conditions
Calm.
Calm

Calm
330°/6 mph
045°/l4 mph
045°/8 mph
24o°/5 mph
060/1 4 mph

060/20 mph
Chips Lost
percent
2
0.15

,,,•
1.7
1.9
1.6
0.15
5

1.6
Comments

Losses occurred over top
of pontoon. Canted noz-
zle should reduce this
somewhat.
73 percent of losses
were fwd through rake.
Test -was at relatively
low rate/high speed.
Canting nozzle should
reduce this type loss.
50 percent of losses
were fwd thrqugh rake.


About same lost on
both sides.
Fairly low chip rate
and high speed probably
contributed to high
losses
Nozzle canted downward.
All chips lost downwind
side.
1.   Rates are percentages of total chips broadcast  in  that
    tests.
2.   Wind directions are relative to model centerline.
                           127

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Later, the nozzle was canted downward about 10 degrees with
the Intention of reducing this type of loss.   That this was
fairly successful is shown by the 1.6 percent loss rate in
test 53 conducted at nominally the same rate as test 52 with
its 5 percent loss rate.   It is therefore concluded that a
loss rate of 2 percent of the number of chips being broad-
cast should be consider"ed typical in strong cross winds.  It
is unlikely that it can be lower than 1 percent.   In winds
of 10 mph or in headwinds, the loss rate should drop to about
1 percent and probably 0-5 percent in winds of less than 5 mpl-

Based on 1170 - 3 x 3-inch chips per second required for
nominal 100 percent area  coverage to recover 10,000 gallons/
hour from a 1.5 mm slick, these loss rates translate into
makeup feeds of 84,200 chips/hour (165 cubic feet/hour) in
strong crosswinds to 21,040 chips/hour (4l cubic  feet/hour)
in winds of less than 5 mph.

DEVELOPMENT OF THE SORBENT CONVEYING SYSTEM

Pneumatic conveying is the selected method of transporting
sorbent material from the regenerating apparatus  at the
after end of the craft to the forward end where it is dis-
tributed on the slick and begins the sorption process.   The
conceptual design envisioned sorbent chips discharging from
the regeneration device into the intake of an axial flow fan
which exhausted into a circular duct, the duct then con-
veying the chips to the distribution device forward.
 I
Development of Conveying  System Concepts

The literature pertaining to pneumatic conveying  which could
be located offered little guidance with regard to low density
material in a chip form and so as mentioned previously, a
small experiment was devised.  The primary purpose was to
investigate air speeds required to properly convey the chips.

A 12-foot-long/9-inch diameter duct was constructed from
clear plastic so that observations could be made.  A one
horsepower centrifugal blower with a materials handling
wheel was obtained (a centrifugal blower for this size model
w,as more readily available and less expensive than an axial
flow fan).
                             128

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It had been hoped to feed chips through the blower but it
was found that the wheel progressively accumulated chips
until either it became effectively plugged or unbalanced.
The wheel was observed with a stroboscope and it was ob-
served that some chips folded over the blade leading edges and
that aerodynamic forces were great .enough to keep them there.
The blades incorporated swept leading edges so that a compo-
nent of centrifugal force acted along the leading edge.
Stringy material for which the wheel was designed, should
slide out and around the open tips.  The sorbent material,
however, exhibited too large .a friction coefficient for this
to take place.

Two venturi injectors were constructed.  The first had a
circular cross section which was too inefficient in terms of
feed area compared to cross sectional area.  Thus a rec-
tangular cross section injector was constructed.

A series of tests was conducted to determine the effects of
air speed on conveying characteristics.  Speed was varied by
choking the blower inlet.  Material properties were also
varied in several directions.  Two material densities and two
chip sizes(3 by 3 inches and 1-1/2 x 1-1/2 inches) were used.
The material was 1/4 to 3/8-inch thick.  High-speed films
were taken of a section of the clear duct.

Examination of the films indicated that a speed of about
30 feet per second was required if the small chips were to
be evenly distributed vertically .in the duct.  The visual
effect of speed was not distinct however, and conveying was
not noticeably poor until a speed of about 25 feet per
second.

Results for the larger (3 by 3 inches) ^chips were more diffi-
cult to interpret as were differences between the two material
densities.  The large chips were too large for the duct and
collisions with the walls were too frequent to judge con-
veying quality.

It was judged that 30 feet per second for 1-1/2 by 1-1/2 in.
chips with a density of 3-6 Ib/cubic foot was the minimum
speed for good conveying.  A dimensionless parameter similar
to the Froude number was used for scaling.  This parameter
is defined as
                              129

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                        V
V
 V

where
          V   =  duct speed-ft/sec,

         Y    =  density of material - lb/ft3,

         Y    =  air density - lb/ft3, and
          a

          ^   =  chip thickness,  ft.

It was felt this relationship could  be applied  as  long as
chip size became no greater than  about 1/6 of the  duct
diameter.  This was the situation with the smaller chips in
the small experiment when wall collisions  did not  seem to
dominate the mechanism.  On this basis, a minimum speed of
about 42 feet per second was required for  the full-size model
using 3 by 3 inch chips.

An important effect revealed in the  :films  was that large,
thin chips are too limp for the process and upon contact with
walls, tend to bend and collapse  and sometimes  flatten com-
pletely against the wall.  The result is a very inefficient
transport mechanism and it was decided,to  make  full-scale
chips stiff enough to reduce this type of  loss.  A thickness
of 3/8 in. for 3 by. 3 inches square  chips  was selected.

Design of Full-Size Model

Table 35 shows the type of losses which were accounted for
in designing the model.  Reference 1 indicated  an axial
flow fan is sufficient to handle  material  to air ratios (by
weight) of about 2.  Initial calculations  called for a fan
output of about 400 cfm at a static  pressure of about 3 inches
of water.  This pressure is near  the limit of a basic axial
flow fan.  Straightening vanes behind the  fan can increase
the capability, but it was felt the  leading edges of the vanes
would greatly reduce the chance that chips could be fed through
the fan.  The latter was important since a centrifugal blower
wheel design was located which seemed to show promise as a
                             130

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1. AIR FRICTION IN DUCT
V2/2g r
. - ,OA f x L/ D
air 69.4 |_
2. CHIP FRICTION IN DUCT
CxW xL
h - m
Chips W x69.4
a
3. ACCELERATION OF CHIPS
W x V2 / 2g
i _ m m
accel W x69.4
a
4. POWER INCREASE IN BLOWER
W xV2t.
HP = m f'P
2g x 550

+ 1.5 f = 0.013 FROM PIPE FLOW DATA
J 1 .5 = EXPERIMENTALLY DETERMINED
NOZZLE LOSS (When deflected )
C IS A "FRICTION COEFFICIENT"
AND « 2. 5 FROM EXPERIMENTS
IF ACCELERATION TAKES PLACE AT
BLOWER OUTLET. OTHERWISE THIS
SHOWS UP AS MOTOR POWER INCREASE.
EXPERIMENTS SHOW NET EFFECTS OF
CHIP + AIR FLOW IN BLOWER INCREASE
THIS POWER
TYPICAL CALCULATED
VALUES L=70, D=1.5
V=45,W 9 Ib/sec
m
0.75
INCHES OF
WATER
1.70
INCHES OF
WATER
0.67
INCHES OF
WATER
4
HP
TABLE 35 - TYPES OF SYSTEM LOSSES

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chip handler and renewed the hope that a venturi would not
be needed.   The wheel design is shown in Figure 36.   Es-
sentially all the centrifugal force acting on a chip which
has folded over a leading edge is directed along the edge.,
which hopefully would be sufficient to clear the blades.

A centrifugal flow blower with the wheel mentioned was
specified for the model.  It was powered with a 7~1/2 horse-
power motor.

The material ratio of 2 and 4-5 feet per second speed yield a
duct diameter of about 16 inches which was increased slightly
to 18 inches.  Sheet metal ducting was obtained and a 7-foot-
long clear plastic section was constructed for observation
purposes.  Total duct length 'was about 58 feet and the noz-
zle was expected to throw 10 feet to complete the 67-1/2 foot
length established in the conceptual design.   The duct was
supported 5 feet above ground level to model prototype wave
clearance.

Because of pessimism regarding feeding through the blower,
an injector was also constructed.  Initial tests with the
blower indicated that chips were captured by the wheel and
so the model was erected with the injector installed.

A sheet metal nozzle similar to that developed on the small*
model was obtained and trial vanes taped' in place.

Sorbent chips were fed into the system with a batch con-
veyor apparatus.  A 10-foot-long by 2-foot-square open box
was constructed and the bottom and both sides lined with
canvas strips attached at one end to the sides and bottom
edges of a 2-foot plywood square.  At the open end of the
box., the bottom canvas was routed under the box and the side
canvases around the sides of the box.  When the free ends
were simultaneously pulled toward, the. closed end of the box,
a three-sided conveyor action took place, carrying up to
20 cubic feet of chips gradually over the lip of the box
into the system inlet (Figure 3).

Chips were broadcast onto a 20 by 40-foot plastic tarpaulin
marked with a grid.

The full-size experiment as originally designed and erected
is shown in Figure 3.
                             132

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FIGURE 36 - THE BLOWER WHEEL DESIGN CAPABLE OF HANDLING
          SORBENT CHIPS
                        133

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Tests and Problem Solving on the Model

It soon developed that the system could achieve only 10 per-
cent of the required chip rate,  limited by the injector.
Various improvements increased this limit to about 33 per-
cent.  At this point it seemed that an injector was too in-
efficient in extracting power from the blower and further
tests were made of the ability of the blower to pass chips.
There was no progressive buildup of chips in or on the wheel
and the model was rearranged to feed into the blower through
the 90-degree inlet elbow and bell mouth which had been de-
signed and built with the rest of the model components.
Wheel RPM was also increased 12 percent to make more power
available.  With these two changes, feed rate increased to
66 percent before a new barrier was reached, choking in the
blower inlet.

The 90-degree turn within a short distance of the blower
has been identified as a potential trouble spot in the de-
sign phase.  Rather than investigate methods of reducing
the problem, it was decided to eliminate the turn by in-
stalling the blower on its side.

In this configuration, feed rates up to 95 percent were
achieved and although speed dropped below good conveying,
there was no indication of reaching a feed-rate limit.   It
is felt that 100 percent rate could have been achieved if
the feed box had been larger.

Having demonstrated that sorbent chips could be conveyed
the required 67-1/2 feet but faced with higher losses than
had been anticipated, it was decided to shorten the duct
to obtain higher air speeds at similar chip rates.  The
modified duct was 27 feet long from blower to nozzle outlet
with the center of a broadcast pattern being about 10 feet
further forward.

Tests Conducted with Regenerated Chips

As discussed earlier, the foregoing tests were conducted
with heavier, dry chips.  To verify the assumption of no
differences between dry and regenerated chips, approximately
Jl gallons of number 6 fuel oil were dumped into the blower
inlet.  The inside of the blower and the nozzle were
thoroughly coated and the ducting was coated to a somewhat

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lesser extent.  The nozzle was locked to one side to produce
the worst condition.

Regenerated chips from Task 3 were conveyed and broadcast
several times at high rate.  No chips were' retained in the
blower or ducting .and only two or three remained in the
corner of the nozzle  (this occasionally occurred with dry
chips for that matter).

Engineering Requirements for.the Conveyor

Enough chips were obtained to provide a 6-second test at
100 percent rate.  This was a compromise between time enough
to make measurements and the problems of working with a very
large number of chips.  Unfortunately, the chips exhibited
a clumping property and entered the intake at a slightly
non-uniform rate so that the system operated at a slightly
unsteady condition. -Data were not very accurate .for these
reasons.

Static pressure measurements were made in the blower inlet
and just downstream of the blower outlet.  Inlet pressure
measurements were not of much value since it was not practi-
cal to provide a long enough straight section of duct to
produce straight streamlines.  All static pressure measure-
ments had to be made with flush taps since a probe is not
usable in the presence of chips.

Motor current was measured to supply data relating to power
requirements.

Measurement of speed in the duct is a problem due to the
chips.  The inside of the duct could have been necked down
to create a venturi but diameters and lengths required to
produce adequate pressure differences looked to be impracti-
cal.  The method used relied on a two-bladed paddle-wheel
mounted in a slot in the duct wall.  Paddlewheel RPM was
measured with a servotach DC generator and calibrated with
a pitot-static tube in the absence of chips.  The flow  is
not homogeneous and chips move slightly slower than the air
but it was assumed adequate  to take the speed determined
from paddlewheel RPM as both air and chip speeds.
                             135

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Required Air Speed in Duct

Observations at the duct outlet and in the clear duct section
installed during part of the model testing indicated that if
speeds dropped below 40 feet per second,  the chips no longer
appeared as a uniform mass and gave the impression of moving
in the lower part of the duct.  This is in general agreement
with the results of the small-scale experiment.

It is concluded that minimum air speed should be 45 feet per
second to obtain good conveying.

Head Losses in the Duct

The head loss in the duct and nozzle is caused by air fric-
tion and chip friction.   For engineering purposes, it was
decided to account for air friction loss  on the basis of
standard pipe flow data as if there were  no chips.  Measured
head losses were reduced by a pipe flow air friction loss and
the remainder attributed to chip friction.

In accordance with Reference 2, chip losses were thought of
as being the energy involved in a frictional force acting
over the length of the duct in a time interval determined
by chip speed.  The frictional force is the product of a
friction coefficient and a normal force equal to the weight
of chips in the duct at any instant.

The friction coefficient was expected to  be about 0.4 but
the test data produced a value of about 2.3 (Figure 37).  In
hindsight, the tumbling and the unsteady speed of individual
chips observed in the high speed films of the small model
may be indicative of greater losses from air drag on in-
dividual chips than if the sorbent were in particle form.
Also, some chips no doubt come to a stop against the duct
wall and must be re-accelerated.  Both types of losses appear
in the experimentally determined "friction coefficient" in
addition to material sliding along the duct.

Characterization of the system is simplified by the fact
that nozzle effects seem to average out with nozzle movement
as shown by the data points on Figure 37.
                             136

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.        C x W  x L
hchips =      m
        W
                                  h =HEAD LOSS IN INCHES OF WATER
                                  C = FRICTION COEFFICIENT
                                  L = DUCT LENGTH IN FEET
                                  Wm =LBS OF MATERIAL/SECOND

                                  WQ = LBS OF AIR/SECOND

-------
Engineering Requirements for the Blower

The blower should be centrifugal rather than axial flow since
in the head range required,  an axial flow fan would require
swirl recovery vanes which would prohibit feeding sorbent
chips through the fan.   It is important that feeding be done
through the fan or blower since the alternative,,  an injector,
is inefficient.

The blower wheel must incorporate certain features if it is
to successfully handle the sorbent chips.  The blades must
extend radially into the hub to eliminate the axially aligned
leading edge present on air handling wheels and some materials
handling wheels.  There must be no rim or front plate on the
wheel so that chips are free to slide along the radial leading
edges and clear the wheel.

Chip Effect on Blower Head,

The presence of sorbent chips in the blower has the effect
of reducing, static head produced at constant RPM and dis-
charge.  The magnitude of this reduction is shown in Figure
38, where F  is the ratio of effective static head delivered
           li
with chips to static head capability of the blower alone at
a given RPM and discharge.

The effect of ?„ on the prototype design will probably be
               ti
a reduction in the material ratio to about 1 rather than 2 as
originally intended.

Chip Effect on Blower Power

Enough power must be transferred to the chaps to give them
wheel tip speed.  Some chips will no doubt slide along blade
surfaces which should show up as a power increase.

Also, even though chips reduce head at constant capacity, it
seems that efficiency is reduced even more so that power in-
creases considerably more than might be allowed for.

Measured motor currents were converted to horsepowers.  A
horsepower due to air only was obtained from manufacturer's
data at the test RPM and capacity.  The difference between
measured and air horsepower was attributed to the total effect
                             138

-------
     Fp = ( POWER REQURIED - AIR ONLY POWER) ^-(CALCULATED CHIP POWER)



          CALCULATED CHIP POWER = W  x V2  /2 g x 550
                                  m   tip
o

u



at.
LU



I
LU
CO


O
I



LU
              0.2   0.4   0.6  0.8   1.0  1.2   1.4   1.6   1.8   2.0
             Wm /WQ - LBS OF MATERIAL PER SEC * LBS OF AIR PER SEC
               EFFECT OF CHIPS ON BLOWER POWER REQUIREMENTS
FH =
 u

 2
 a

 &
 x
 u
 CO

 i
(EFFECTIVE STATIC HEAD PRODUCED) * ( STATIC HEAD EXPECTED WITHOUT CHIPS)


 1.00
              0.2   0.4  0.6  0.8   1.0  1.2   1.4   1.6   1.8   2.0
           W  /W  - LBS OF MATERIAL PER SECOND * LBS OF AIR PER SEC
            m    a


                   EFFECT OF CHIPS ON BLOWER STATIC HEAD



        FIGURE  38 - EXPERIMENTALLY DETERMINED FACTORS WHICH ACCOUNT

                   FOR THE EFFECT OF CHIPS ON BLOWER HEAD AND POWER

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of chips.   These powers were compared to the power required
to accelerate the chips to tip speed to produce a measure
of power efficiency to be applied in conjunction with the
pressure efficiency discussed earlier.   Values of this factor,
F ,  are shown in Figure 38.    This approach to power require-

ments Implicitly includes the chip acceleration loss defined
in Table 35.

Model of System Operation

Figure 39 presents a graphical model of a concept of the
system which accounts for losses and the effects of chips
on blower head and power.

Validity of Head and Power Factors

The sorbent- broadcast model is a very specialized applica-
tion of pneumatic conveying and the correlations produced
by the tests cannot be expected to hold if applied to a
system much different from the model.   It was for this
reason,, of course., that the model was made as near the con-
ceptual design as possible.
                               0

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        STATIC HEAD AT RPM  2
   SYSTEM OPERATES AT POINT 1 WITH NO
   CHIPS BEING CONVEYED
   IF CHIPS DID NOT AFFECT FLOW IN BLOWER,
   THEN WHEN CHIPS ARE CONVEYED, THE
   CAPACITY DROPS DUE TO DUCT LOSSES,
   POWER INCREASES OVER AIR HORSEPOWER
   TO IMPART TIP SPEED TO CHIPS, AND "PM
   DROPS VERY SLIGHTLY. SYSTEM WOULD
   OPERATE AT THE HYPOTHETICAL POINT  2
   SINCE CHIPS DO AFFECT THE BLOWER, HEAD
   DELIVERED DROPS AND POWER INCREASES
   AND THE SYSTEM ACTUALLY OPERATES
   AT POINT 3 . POINT 3 MUST FALL ON A
   LINE WHICH DESCRIBES DUCT LOSSES.
4.  IN DESIGN, POINT 3 IS THE KNOWN
   STARTING POINT.
       CAPACITY, Q
FIGURE 39 - MODEL OF HEAD AND POWER INTERACTIONS BETWEEN BLOWER, DUCT, AND CHIPS

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Sample Calculation
I.   Design Conditions
     1.  Nominal slick coverage   4400 ft2/min (conceptual
                                  design)
II.
     2.  Density of regenerated
         chips
     3.  Chip dimensions
     4.  From 1,2, and 3, chip
         rate
     5.  From 2 and 3 chip
         weight
     6.  Duct speed with chips
     7.  Duct length
     8.  Weight sorbent/weight
         air
     9.  Density of air
     Duct size calculation
                                   3.6 lb/ft3
                                   3 x 3 x 3/8 in.

                                   1172 chips/sec

                                   0.00705 Ib/chip
                                   45 ft/sec
                                   67.5 ft (conceptual design)

                                   1.0 nominal
                                   0.075 lb/ft3
     1.  Weight of material, W  = 1172 x 0.00705 = 8.26 Ib/sec
     2.  Weight of air,
                              W  =1.0x8.26 = 8.26 Ib/sec
                               a                       '
     3.  Total volume flow rate Q = volume of sorbent
         + volume of air

                           =
                                              60 - 67*6
     4.  Duct sectional area
               Q = Area x Speed
            Area = 6746/45 x 60 = 2.50 ft2
        „.   ,     -\ ' 4 x Area
        Diameter = \.
                        ir
                                  \ - 4 x 2.50
                                  'v     7T
= 1.78 ft
  (21.36 in.)
                            142

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III.  Duct losses  (Table 35)



      .1... Air friction, h  =  * /^  .f x - + 1.5!




          ,   _      (45)g             67 5

           f ~  69.4 x 64.4   °'013 x TlQ + 1>5i = °'9° ln' of
                                                /   water


                                       W  x L
      2.  Chip friction h-  .   = C x    m
                          chips       W  x 69.4
                                      3
          hohlps • 2-3 * o  x   :  - 2-23 in. of water
      3.  Total duct loss = air + chips



          h = 0.90 + 2.23 = 3.13 in. of water



 IV.  System operating point  (point 3 on Figure 39)


          Q = 6746 ft3/min


          h = 3.14 in. of water



  V.  Inclusion of chip  effect on head



          From Figure 38, when ^m/^a =1.0



                   Fh «  0.30


              to deliver h =  3.14, blower must operate at

              an apparent condition,


          Q  =  6746


          H  =  3.14/0.30 = 10.47

                (this is point 2 on Figure  39 ).
                              143

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 VI.   Blower RPM and air horsepower at point 2.  (Based on
       American Standard Size 21 long shaving type blower

       with a 36-1/2 inch wheel diameter)

                          1204 RPM

                         17.41 h
                                Pair


VII.   Ideal chip horsepower and allowance for chip effect

       on chip horsepower.

       1.  Wheel tip speed = ^'\^J^ 12°4 = 192 ft/sec.

                              V2   /2g x W
       2.  Ideal chip power = —  P  „	 (Figure 38 )
                                   550

           hn      - (192)2 X 8.26 _ o ^
           hpideal -  64.4 x 550   = 8'6°
       3.   Prom Figure 38 when W /W  =1.0
                         Fp • 3-3

           Actual chip power = Ideal chip power x F


           ""actual ' 8'6° x 3-3 = 28'38
       4.   Actual operating power = actual chip power + air
           power

           H  = 17.41 + 28.38 = 45.99
                               144

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                         APPENDIX C

        DEVELOPMENT OP THE HARVESTING CONVEYOR AND
              OVERALL OIL RECOVERY PERFORMANCE

The objectives of this task were:

     1.  Determine the conveyor inclination angle and speed
         for optimum performance.

     2.  Using the optimum conveyor operating condition,
         develop data on system performance as a function
         of the other operating parameters.

The system performance was defined in terms of the per-
centage of oil recovered from the slick and the percentage
of oil in the recovered fluid.  The performance goals given
by the EPA were 100 percent recovery of the oil from the
slick and in excess of 90 percent oil in the recovered fluid.
The operating parameters which were studied in addition to
the conveyor angle and speed included:
                                    *
         Slick thickness and viscosity' (oil type and
         temperature)

         Sorbent coverage
         Residence time

         Calm water versus waves

The harvesting conveyor test setup was installed, in a
80-ft towing tank along with the sorbent chip distribution
carriage.  Figure 5 shows a picture of the harvesting con-
veyor which can be run at speeds up to 3-5 ft/sec with the
variable speed drive installed.  The conveyor consists of
1 in. mesh opening flat wire belt.  Figure 6 shows a picture
of the sorbent ctyLp distribution carriage.  This carriage
is equipped with a moving belt feed device which feeds the
chips to a rotating paddle wheel spreader.  This device is
used to distribute the chips in the tank in a random fashion.

The test procedure is to cover a 55-ft length of the tank
with a known Quantity of oil.  The sorbent chip distribution
carriage is then run down the tank at a fixed speed to dis-
tribute a known amount of sorbent on the slick.  After waiting

-------
the required residence time,  the harvesting conveyor follows
down the tank and picks up the chips and drops them in a col-
lection box.  After the run,  the chips in the box are re-
generated and the.amount of oil and water recovered is
measured.  The oil remaining in the tank is collected and
measured to determine the amount of oil not recovered.  Fig-
ure 7 shows a typical test In progress.  .       ;
                 v.                    "''    ''   V" '  i
The initial tests were directed- at.determining the optimum
conveyor angle and conveyor speed relative to forward speed.
Typical results are shown in Figure 4'0.  In this figure,
the total percent of oil recovered and the percent of oil in
the recovered fluid are plotted as a function of the conveyor
speed ratio. ' The conveyor speed ratio Is defined as

             (Conveyor Speed) x (Cosine Conveyor Angle)
                           Forward Speed
The test conditions are noted in the figure.   The total per-
cent of oil recovered does not seem to be a .function of the
conveyor angle.  However,  it is a function, of the conveyor
speed ratio.  At low speed ratios,  the chip distribution
density increases In front 'of.the conveyor, during collection.
This slightly increases total percentage-recovery of oil.
This condition also forces more water into the ..chips so that
the percentage of oil in the recovered fluid drops.   At high
conveyor speed ratios the  percentage of oil in the recovered
fluid also drops because of the entrained water droplets
carried by the conveyor.  The 45-degree conveyor angle is
superior to the 30 degree  angle since less water is recovered
with the oil.  The 45-degree angle results. In less water be-
cause less water is entrained with the conveyor and there  is
a greater tendency for water to run off the chips.  Tests
In waves indicate they cause an increase in the percent of
oil recovered.  This Is because the waves agitate the sorbent
chips causing contact with a greater area of the slick.  Ob-
servations indicate that the conveyor angle cannot be in-
creased much above 45 degrees without the use of flights.
Thus, based on these tests a conveyor angle of 45 degrees
and a conveyor speed ratio of 0.7 seem to be optimum.

The system performance as  a function of slick thickne'ss and
oil viscosity is presented in Figures 4l through 44.  Fig-
ures 4l and 43 give the percent oil recovered and Figures.42
                              146

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UJ
U
ae.
UJ
BL.
   100
    90
    80
    70
    60
    50
    40
    30
             	45  CONVEYOR ANGLE
             	 30° CONVEYOR ANGLE
O = PERCENT OF OIL RECOVERED
D = PERCENT OIL IN TOTAL RECOVERED FLUID
NOTES:
    1.5 mm  SLICK OF #4 FUEL OIL
    30 SECOND  RESIDENCE TIME
    3"x3"x3/i3" 80ppi SORBENT CHIPS
    NOMINAL CHIP AREA/SLICK  AREA = 0.875
    FORWARD SPEED = 2.25 ft/sec
       0.40       0.60       0.80       1.00        1.20       1.40

              HORIZONTAL CONVEYOR VELOCITY/FORWARD SPEED
             FIGURE 40 -  HARVESTING CONVEYOR PERFORMANCE
                             14?

-------
100
Q
UJ
O£
UJ

>

o

U
UJ
cz
 90




 80




 70




 60




 50




 40




 30




 20




 10




  0
                                 1.5mm SLICK THICKNESS
                              0.5 mm SLICK THICKNESS

                                                                         \
OPEN SYMBOLS = 1 .5 mm SLICK THICKNESS

SOLID SYMBOLS = 0.5 mm SLICK THICKNESS
                     30 sec.


                       °
              RESIDENCE TIME:


              CONVEYOR ANGLE: 45


              RECOVERY SPEED:     2.25 ft/sec.
          NO. 4 OIL

         -h-—	-4
NOMINAL SORBENT

    COVERAGE





     O  87^


     D  65*
                                             l
                                                                   BUNKER "C
                        100
                                           1000
                                                                                 10,000
                                           VISCOSITY, cm  /sec


                            FIGURE 41 -  OIL RECOVERY VS. VISCOSITY (CALM WATER).
                                                                                                                      00

-------
Q
5
u.
Q
O
u
O
100


 90


 80


 70


 60


 50


 40


 30


 20


  10
           _                         0.5 mm SLICK THICKNESS	
              e-
              a
                                                 1 .5 mm SLICK THICKNESS
                       NOMINAL SORBENT
                            COVERAGE

                            A  107*
                            O  87*
                                                                       RESIDENCE TIME:     30 sec.

                                                                       CONVEYOR ANGLE:  45°

                                                                       RECOVERY SPEED:     2.25  ft/sec.
                                                                  OPEN SYMBOLS = 1.5 mm SLICK THICKNESS
                                                                  SOLID SYMBOLS = 0.5 mm SLICK THICKNESS
          20
                     100
1000
                                                                        10,000
100,000
                                                 VISCOSITY CM* / SEC
                            FIGURE 42 - PERCENT OIL IN RECOVERED FLUID VS. VISCOSITY ( CALM WATER)

-------
f—
U1
o
                   Q
                   LU
                   O
                   u
                   LU
100



 90



 80



 70



 60



 50



 40



 30



 20



 10
 RESIDENCE TIME:     30 sec.

 CONVEYOR ANGLE:  45°

 RECOVERY SPEED:    2.25 ft/sec.


OPEN SYMBOLS = 1.5 mm SLICK THICKNESS
SOLID SYMBOLS = 0.5 mm SLICK THICKNESS
NOMINAL SORBENT
    COVERAGE

     A  107$

     O   87^

     O   65%
                                         J	I
                                              100
                                                 1000

                                           VISCOSITY, cm2/sec
                                                                    10,000
                                                  FIGURE 43 - OIL RECOVERY VS. VISCOSITY (WAVES)

-------
I—
                          u_

                          Q
                          UJ
                          Q£
                          UJ


                          O
                          u
                          UJ


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                          o
100
90
80
70
60
50
40
30
20

10
0
P_ 1.5 mm SLICK O A
- o 0
A
~ • 	 .__—• — —' —
_ A



NOMINAL SORBENT
- COVERAGE
A
o
RESIDENCE TIME:
107*
87*
65*
30 sec.
— CONVEYOR ANGLE: 45°
RECOVERY SPEED:
2.25 ft/sec.
— OPEN SYMBOLS = 1 .5 mm SLICK THICKNESS
SOLID SYMBOLS = 0.5 mm SLICK THICKNESS
1
                                  20
100
1000
                                                                              VISCOSITY CM  /SEC
10,000
100,000
                                                   FIGURE 44 - PERCENT OIL IN RECOVERED FLUID VS. VISCOSITY (WAVES)

-------
and 44 give the percent oil in the recovered fluid.   Fig-
ures 4l and 42 are for calm water and Figures 43 and 44 are
for waves of 3 inch height and 4 foot length.  These figures
are based on a sorbent residence time of 30 seconds.  It
should be noted that the tests were carried out with a two-
dimensional section of the actual conveyor at prototype speeds,
oil type and slick thicknesses with the prototype sorbent.
Consequently,  the results are applicable to the actual unit
and scaling of the data is not required.  The performance in
terms of the percent of oil recovered and the percent oil
in the recovered fluid is better in a slick of 1.5 mm thick-
ness than in a slick of 0.5 mm thickness.  This is as ex-
pected since the thicker slick provides more flow area into
the sides of the chips and the larger volume of oil  recovered
tends to improve the percent oil in the recovered fluid.   The
percent recovery is better in waves because the waves agitate
the chips causing them to contact a higher percentage of the
surface.  Figure 43 presents data which indicates that with
small waves and a uniform sorbent distribution, the  actual
unit will recover over 90 percent of the oil in 0.5  mm and
1.5 mm slicks  for oil viscosities up to 10,000 cm2/sec.   The
8 to 10 percent of the oil which is not recovered is due to
the portions of the slick not contacted with sorbent, losses
from chips on  the harvesting conveyor and oil washed off the
harvesting conveyor.  Tests indicate that about 15 percent
of the oil not recovered is washed off the harvesting con-
veyor and less than 5 percent is lost from the chips on the
harvesting conveyor.  Operation in waves also increases the
amount of water recovered due to the agitation of the sorbent
chips.  Figure 44 indicates that in small waves the  require-
ment for 90 percent oil in the recovered fluid can be satis-
fied in a 1.5  mm slick but not in a 0.5 mm slick.  A further
analysis of the water recovery rate Is presented in a fol-
lowing paragraph.

The system performance in terms of percent oil recovery as
a function of  sorbent residence time is presented in Fig-
ure 45 for calm water and Figure 46 for waves.  The important
conclusion from these two figures is that there is little
or no increase in the percent recovery for residence time in
excess of 30 seconds for the slick thicknesses and oils
tested.  The percent of oil recovered does not tend to de-
crease rapidly until the residence time is reduced to 10
seconds or less.
                              152

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LU

O
u
UJ
O£
O
100


 90


 80


 70


 60


 50


 40


 30


 20


 10
                                                      1.5 mm SLICK
                                         0.5mm SLICK THICKNESS
                 10
                             45° CONVEYOR ANGLE
                             2.25 FT /SEC RECOVERY SPEED

                           O # 4 OIL AT 20° C
                           a f 6 OIL AT 20° C

                             OPEN SYMBOLS = 1.5 mm SLICK THICKNESS
                             SOLID SYMBOLS = 0.5 mm SLICK THICKNESS
                             87$ NOMINAL SORBENT COVERAGE
                             SYMBOLS WITH TAILS = 107$ NOMINAL COVERAGE

                            I     I      I	 I     I     I     I     I     I
                        20
                                      30
40
                                                       50
60
                                 RESIDENCE TIME SEC
                 FIGURE 45 - OIL RECOVERY VS. RESIDENCE TIME (CALM WATER)
                                     153

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    100


    90


    80


    70
UJ
O
u
=!   50
O
v-
     40


     30


     20


     10

     0
            45° CONVEYOR ANGLE
            2.25 FT /SEC RECOVERY SPEED
         O  * 4 OIL AT 20° C
         D  # 6 OIL AT 20° C

            OPEN SYMBOLS = 1.5 mm SLICK THICKNESS
            SOLID SYMBOLS = 0.5 mm SLICK THICKNESS
            67% NOMINAL SORBENT COVERAGE
            SYMBOLS WITH TAILS = 107$ NOMINAL COVERAGE

I     I     I      I     I     I     I     I	II	I
                10
               20        30         40
                              RESIDENCE TIME SEC
50
60
              FIGURE 46 - OIL RECOVERY VS. RESIDENCE TIME (WAVES)
                                  154

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The percent oil recovery  as  a  function  of  nominal  sorbent
coverage is presented  In  Figure  47.   Data  are  presented for
calm water and waves for  residence  times of  15 and 30 seconds
The nominal sorbent  coverage is  defined as the total projected
area of the sorbent  chips divided by the area  of the slick
Even with a 100 percent nominal  sorbent coverage,  small local
areas of the slick are not covered  because some of the sor-
bent chips will overlap each other.   Small waves counter this
effect by moving  the chips around on the surface.  This wave
action also reduces  the required nominal sorbent coverage for
maximum oil recovery.  For example,  Figure 47  indicates that
at 30 seconds residence time in  calm water,  a  90 percent
coverage is required for  maximum oil recovery.  In waves,
maximum oil recovery can  be obtained with  between  70 and'80
percent coverage.

The basic format  used  in  Figure  47  is suitable for synthesizing
data presented in previous figures  in a form convenient for
system design studies.  The result  is a cross  plot which pre-
sents percent oil recovery as  a  function of  residence time and
percent sorbent coverage.  Several  plots of  this type could
be constructed to cover the range of oil viscosity and slick
thicknesses of interest.   An example is presented  in Figure
48.  This figure  presents  percent  oil  recovery in waves and
is appropriate for slick  thickness  from 0.5  mm to  3 mm and
oil viscosities less than or equal  to 6000 cm2/sec.

Previous figures  (42 and  44) presented  data  on the percent
of oil in the recovered fluid.   It  was  observed in the tests
that the water recovered  was from two sources.  Some of the
water is absorbed in the  sorbent along  with  the oil or re-
mains on the surface of the sorbent in  the form of droplets.
The remainder of  the water is  entrained by the harvesting
 conveyor and sprayed onto the  collected sorbent.   It-'is im-
portant for prototype  predictions to separate  these two
 sources of recovered water since the first is  a function of
the amount of sorbent  and the  second is a  function of the
width and speed of the harvesting conveyor.  Figure 49 pre-
 sents data on the water recovered which is absorbed in the
 sorbent material  itself.   These  data are scattered but do
 indicate that high viscosity oil in the sorbent tends to re-
 duce the amount of water  recovered.   The agitation of small
waves tends to increase the amount  of water  recovered.  There
 is no consistent  indication that more water  is recovered by
 the sorbent in thin  slicks (0.5  mm) than in  thicker slicks
 (1.5 mm).  Figure 50 presents  data  on the  rate at  which the


                               155

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100


 90


 80


 70


 60


 50

 40


 30


 20


 10


 0
              1.5 mm OF #4 OIL
            D 15 SEC RESIDENCE TIME
            030 SEC RESIDENCE TIME
              SOLID SYMBOLS = OPERATION IN WAVES
              45° CONVEYOR ANGLE
              2.25 FT / SEC RECOVERY SPEED
I     I     i     I    J     I
                           I     !
        10
     20    30
40
50   60    70    80    90   100  110
                NOMINAL SORBENT COVERAGE  -  PERCENT
    FIGURE 47 - OIL RECOVERY VS. NOMINAL SORBENT COVERAGE
                           156

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   120






   110





   100





    90





>.   80
a:
HI



8   70
UJ
O   60

»—

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ua   en
U   50
          80 PP! POLYURETHANE CHIPS 3"x3"x 3/8"

          SLICK THICKNESS 0.5-3mm

          OIL VISCOSITY < 6000 CM2/SEC
LU
a.
    40




    30




    20




    10




     0
           10    20    30   40    50    60   70   80   90   100  110  120



                           PERCENT SORBENT COVERAGE
              FIGURE 48 - SORBENT OIL RECOVERY PERFORMANCE IN WAVES
                                   157

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              o
              to
                    0.03
                                          NOMINAL SORBENT COVERAGE
                                                    A 107*
                                                    O 87*
                                          OPEN SYMBOLS = CALM WATER
                                          SOLI D SYMBOLS = WAVES

                                          WITH TAILS = 0,5 mm SLICK
                                          WITHOUT TAILS = 1.5 mm SLICK
                    0.02 —
                                                                               WAVES
on
              O
                    0.01

                        20
                                O
                                A
                                       CALM WATER
                                                                                                 I
100
1000
                                                                     VISCOSITY CM* /SEC
10,000
100,000
                                              FIGURE 49 - WATER RECOVERED BY SORBENT VS. SLICK VISCOSITY

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u
iu
to
u
UJ
to
to
z
o
o
LU



Z
     8.0
     7.0
6.0
     5.Ox 10
     4.0
     3.0
     2.0
     KOx 10
     0.0
           .-4
                                   \
                                   X30° CONVEYOR ANGLE
                                             -45° CONVEYOR ANGLE
                                 234



                                 CONVEYOR SPEED FT / SEC
         FIGURE 50 - WATER ENTRAPMENT RATE DUE TO CONVEYOR VS. CONVEYOR SPEED
                                   155

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harvesting conveyor entrains water and sprays it as droplets
onto the collected sorbent.   It should be noted that this rate
is greatly reduced by increasing the conveyor angle to 45 de-
grees.   This is a major reason for selecting as steep a con-
veyor angle as possible.

Summary

As a result of the work carried out under this task an optimum
conveyor angle and speed ratio has been selected and the data
necessary-, to predict the performance of the system under a
wide range of conditions have been collected and analyzed.
These data indicate that the oil recovery can range from 90 to
95 percent over a wide range of oil types and slick thicknesses
The percent oil in the recovered fluid will meet the EPA goal
of 90 percent for slick thicknesses of 1.5 mm.
                              160

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                         APPENDIX D

           SORBENT REGENERATION SYSTEM DEVELOPMENT

The objectives of this task were:

         Develop performance data for a converging belt*type
         sorbent regenerator as a function of the design
         parameters.

         Determine the effects of repeated cycles on the
         sorbent material.   '  '

         Identify and resolve mechanical problems prior to
         the construction of a prototype system.

These objectives were satisfied by designing, building and
conducting tests with a sorbent regenerator test  apparatus.
The function df the sorbent regenerator is to squeeze the
recovered oil out of the sorbent chips so that the chips are
ready for broadcasting.  In a typical case using  3 in.  by
3 in. x 1/4 in. sorbent chips, a cubic foot of sorbent ma-
terial will recover about 2 gallons of oil.  The  sorbent re-
generator must remove the oil from the sorbent and maintain
the density of the sorbent at a low enough value  for broad-
casting.  Thus the performance of the sorbent regenerator
can be defined in terras of the density of the regenerated
sorbent after the removal of 2 gallons of oil per cubic foot.
The parameters which influence the density of the regenerated
sorbent are:

         Squeezing Force
         Oil Viscosity
         Sorbent Loading
         Sorbent Type
         Belt Speed

Test Apparatus and Procedures

A converging belt sorbent regenerator test apparatus was de-
signed and built.  Figure 51 shows an outline drawing of this
apparatus and Figure 52 shows a photograph of it  set up for
testing  ' The test apparatus consists of two 18-inch wide
converging conveyor belts which run between two pairs of
squeezing rollers.  The lower belt is an open steel mesh
                              161

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             STEEL BELTS
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                                                                                            CHAIN
LOWER BELT SPROCKET
AND BELT DRIVER
"V IDLER AND CHAIN
   TENSIONER
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                              FIGURE 51 - SORBENT REGENERATOR TEST APPARATUS

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FIGURE 52 -  SORBENT REGENERATOR TEST APPARATUS SET-UP
                        163

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(Type B-60-32-14 Balanced Belting) and the upper belt is a
similar material covered with segmented neoprene pads.   The
two belts are driven by a chain drive system in which the
speed can be adjusted by changing sprocket size.  The squeez-
ing pressure is applied to the upper roller in each pair by
an air cylinder acting through a yoke.  The squeezing pres-
sure can thus be adjusted by simply adjusting the air pressure.
Oil collecting pans are located under both legs of the lower
belt.  The recovered oil flows by gravity out of the collect-
ing pan spouts to a storage barrel.

In order to avoid scaling problems with the data and to
identify mechanical problems, the test apparatus was designed
to be near full scale for the 3000 GPH recovery unit.   It is
intended to scale the system up for the 10,000 GPH unit by
simply making it wider.

The tests were conducted by taking a known volume of sorbent
material and saturating it with between 1.5 and 2 gallons of
oil per cubic foot.  The sorbent was then run through the
regenerator and its density determined by weighing.   This
process was repeated until the density of the regenerated
chips reached an equilibrium value.   The tests were conducted
for a range of belt speeds, squeezing force,  oil type,  sor-
bent type and .sorbent loading.  The sorbent loading is  defined
as the volume of sorbent per unit belt area and has the di-
mensions of feet.  The sorbent loading times the belt width
times the belt speed gives the sorbent regeneration rate in
cubic 'feet/second.   The effect of more than two pairs of
squeezing rollers was simulated by quickly recycling the re-
generated sorbent.

Preliminary bench tests, during the design phase, indicated
that a squeezing force of 50 pounds per inch of belt width
would be satisfactory.  However, preliminary testing showed
that this was not sufficient to reduce the sorbent density
to the desired range (i.e. 5 to 7 lbs/ft3).   As a result it
was necessary to increase the shaft diameters on the squeezing
rollers to allow testing at higher forces.

System Performance

The performance of a converging belt sorbent regenerator, in
terms of the density of the regenerated sorbent, is presented
in Figure 53 thru 55 as a function of the test parameters.
                              164

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               D  0.428 Ft3/Ft2


               A  0.316Ft3/Ft2


             OPEN SYMBOLS  0.43 Ft/Sec BELT SPEED


             SOLID SYMBOLS 1.00 Ft/Sec BELT SPEED
                  50          100         150         200



                     SQUEEZING FORCE Lb/ln OF BELT WIDTH
   FIGURE  53 - REGENERATED SORBENT DENSITY VS. SQUEEZING

                 FORCE (80 PPI FOAM) NO. 2 HEATING  OIL
                               16 5S

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                  SQUEEZING FORCE Lb/ln OF BELT WIDTH
   FIGURE 55 - REGENERATED SORBENT DENSITY VS. SQUEEZING

               FORCE (30 PPI FOAM) BUNKER  "C"
                          167

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Figure 53 is for 80 PPI roam and No.  2 heating oil.   Figure
54 is for 80 PPI foam and an oil product made by mixing 70
percent Bunker "C" and 30 percent No.  2 heating oil.   Fig-
ure 55 is for Bunker "C" and presents  points for both 80
and 30 PPI foam.  The viscosities of  the oil products used,,
as a function of temperature,  are given in Table 36.   These
figures indicate that the density of  the regenerated  sorbent
is most sensitive to squeezing force,  oil viscosity and sor-
bent type (80 or 30 PPI).   The sorbent loading also has a
significant effect on the density.  The results were  basically
insensitive to belt speed in the range from 0.4 to 1.0 ft/sec.

                         TABLE 36

              Viscosity of Test Oil Products
Temperature
degrees, C
30
20
10
5
Viscosity: Centipoise
No. 2
2.2
2.6
3.2
4.0
30 percent No. 2
70 percent Bunker "C"
120
800
2300
12000
Bunker C
2120
4500
20000
153000
  Figure 56 presents a summary of regenerator performance
  as a function of oil viscosity for a typical design point.
  The design point parameters are a squeezing force of 220
  Ib/in. a sorbent loading of 0.25 ftfft2 and a belt speed
  of 1.0 ft/sec or less.   This figure shows the need for
  using 30 PPI foam when dealing with oil viscosities in
  excess of 1000 ops.   At this squeezing force it is possible
  to regenerate sorbent which contains oil with viscosities
  up to 20,000 cps.  However, the density of the regenerated
  sorbent increases above the desired level and heating will
  be required to get satisfactory flow in the oil collecting
  pans.  Figure 56 also illustrates the benefits of In-
  creasing the number  of squeezing rollers.

  Mechanical Details

  The tests conducted  with the heavy oils indicated some
  tendency for the sorbent chips to stick to the lower belt
  and to be carried into the lower collecting pan.  A simple
                              168

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            2 SQUEEZE ROLLERS UNLESS NOTED
                                                              X
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                                                                                  "*-30 PPI FOAM
                                                                        4 SQUEEZE
                                                                          ROLLERS
                                                     SQUEEZE
                                                     ROLLERS
                                                             DRY SORBENT
                                                         1000
                                                                            10,000
                                                                                              100,000
                                           VISCOSITY C  / Sec
                                                     m
                 FIGURE 56 -  REGENERATED SORBENT DENSITY VS. VISCOSITY

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mechanical scraper is not sufficient to remove these chips.
As a result,  a rotating brush driven by the belt drive should
be installed on the prototype.   This should remove the chips
without difficulty.  Also,  since some sorbent chips will find
their way into the collecting pans,  provision should be made
for periodic cleaning of these pans.

It was also noted during early tests that sorbent chip's
were caught in the drive, chains at the edges of the upper
and lower belts and ultimately ground up.  Simple wooden
chain guards were added to the test apparatus and solved
the problem.   Similar guards made of a more durable material
should be fitted on the prototype device.

In the test apparatus the upper and lower belts were the
same material and the upper belt was made solid by attaching
neoprene pads to it.  This will not be a satisfactory ar-
rangement for the prototype regenerator.  The upper belt
should be simple reinforced neoprene belt or a wire mesh
belt of the type used impregnated with neoprene.

The air cylinders used to provide the squeezing force gave
excellent, service and provide a simple and reliable means
of applying and controlling the squeezing force.  The shafts
in the squeezing rollers should be designed to withstand
the loads applied by a piece of drift wood or debris going
through the regenerator.  For the 3000 GPH unit 1-1/2 inch
diameter high strength steel shafts should be satisfactory.

An endurance test was conducted to determine the effects of
repeated regenerations on the sorbent material.  These tests
were carried out by saturating a group of chips (about 20)
and running them through the sorbent regenerator test ap-
paratus at a high enough squeezing force to reduce their
density to 6 Ib/ft3.   This process was repeated 100 times
for 80 PPI chips using a mixture of 90 percent Bunker "C"
and 30 percent No. 2 oil and for 30 PPI chips using Bunker
"C".  Figure 57 presents a photograph of chips that were
regenerated 1, 50 and 100 times.  There was no significant
degradation of the sorbent chips after 100 cycles.

Results

The important results of this task can be summarized as
follows:
                            170

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           Heavy numbers indicate the number of times
           sample  sorbent chips were  regenerated
                             7   8    i       I!
FIGURE 57 - SORBENT CHIPS AFTER ENDURANCE TEST
                    171

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A converging belt sorbent regenerator will satis-
factorily regenerate sorbent chips at the volume
rates required.

The density of the regenerated chips will be about
6 lb/ft3 for a squeezing force of 220 Ib/in. a
sorbent loading of 0.25 fts/ft2 and a belt speed
of 1 ft/sec.

In order to maintain a 6 lb/ft3 regenerated sorbent
density, 30 PPI foam should be used for oil vis-
cosities in excess of 1000 cps.

An oil viscosity of about 20,000 cps at the time
of regeneration is the practical upper limit be-
cause of the excessive density of the regenerated
sorbent.

The sorbent material can be cycled 100 times without
significant degradation.
                   172

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                       APPENDIX  E

    MODEL TEST OP A 1/4 -SCALE MODEL RECOVERY  PLATFORM

The objectives of this task were:

     1.  Demonstrate that a continuous  stable sorbent
         broadcast and recovery  cycle is possible.

     2.  Determine any adverse effects  of waves and forward
         speed on the continuous broadcast and recovery cycle,

     3-  Determine the towing resistance and  stability of the
         recovery platform at the  deployment and operating
         draft.

The objectives of this task were carried out by means of
tests on a 1/4 scale model of the  recovery platform in the
HYDRONAUTICS Ship Model Basin, (HSMB®).  The model was
equipped with an operating broadcasting system and harvesting
conveyor.  No squeezing system was fitted so no attempt was
made to actually recover oil.

The most important results of the  test program were the
qualitative observations with respect to the feasibility of
a continuous., stable, broadcasting and recovery cycle under
different operating conditions.  Quantitative data were ob-
tained on the towing resistance of the recovery platform
under different conditions.  A description of the model,  the
test procedure and the results are presented in the following
paragraphs.

Description of Model and Test Facilities

The basic concept for the recovery platform was developed
in the original HYDRONAUTICS, Incorporated Sorbent Oil Re-
covery System Proposal.   Subsequently, preliminary efforts
showed that the basic concept and general proportions were
still valid.  As a result, the model design was based on
the original concept and was sized to be a 1/4 scale model
of a system intended to recover 10,000 gallons per hour.

A 1/4 scale aluminum model of the recovery platform equipped
with an operating sorbent broadcasting and recovery system
was constructed.  Figure 58 presents an arrangement drawing
for the model with its dimensions.


                            173

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The broadcasting  system  on  the  model  was  based on the work
reported in Appendix B.   The  movable  parallel plate nozzle
was a scaled down version of  the  one  tested in Task 2, and
equipped with a simple mechanical drive.  No attempt was  .
made to scale the actual blower.   Rather, the blower avail-
able from  the small scale experiments  conducted under Task 2
was used.  The air flow  necessary for  good sorbent distribu-
tion was obtained by choking  the  blower inlet.

The harvesting conveyor  angle of  45 degrees was based on
the 'results of Task 3.   It  was  not practical to obtain a
conveyor belt material that was a 1/4  scale model of that
used in Task 3.   However,, it  was  felt  that this was not im-
portant.   Instead, a light  weight wire belt with 1/4 inch
high wooden flights was  used.  The harvesting conveyor was
driven with a-variable speed  drive so  that the linear con-
veyor speed could be adjusted to  equal the towing speed of
the platform.  A  transfer conveyor was fitted between the
aft pontoons of  the platform  to collect the sorbent chips
from the harvesting  conveyor  and  feed them to the broad-
casting  system blower.   The transfer  conveyor was also
fitted with a variable speed  drive.   Figure 59 presents
photographs of the mechanical systems  described above.

The sorbent material was simulated with a white color,
closed  cell foam. This  foam  was  cut  to 1/8 in. thick, 3/4
in. by  3/4 in. squares.

The tests  were carried out  in the HYDRONAUTICS, Ship Model
Basin at HYDRONAUTICS,  Incorporated.   This towing tank is
equipped with a  towing  carriage with  a top speed of 20 ft/sec,
and with Instrumentation to measure  forces, motions and wave
height.  A plunger type  wavemaker is  fitted at one end of
the towing tank  which  Is capable  of  generating regular and
long  crested  irregular waves.  The dimensions of the towing
tank are:
                          Length   308 feet

                          Width       25 feet
                          Depth       13 feet

Test Procedures

The towing tests  were  carried out with the model  towed be-
hind the  towing  carriage on about 30 feet of  towline.  The
towline  ran  from a 60 degree  bridle  between  the forward


                              175

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Broadcasting Nozzle and Drive
                                        Transfer Conveyor and Drive
                   Harvesting Conveyor and Drivs
   FIGURE 59 -  MECHANICAL DETAILS OF SORBENT RECOVERY
                PLATFORM MODEL
                            176

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pontoons, under the carriage,  to a force measuring block
gage mounted on a post at  the  forward end of the carriage.
A sonic wave height probe  was  mounted on the forward end
of the towing carriage to  measure the height of the incident
waves.  A capacitance type wave height probe was mounted
outboard on the aft port pontoon at  the same longitudinal
location as the lower end  of the harvesting conveyor.  The
purpose of this probe was  to measure the relative motion be-
tween the waves and the recovery platform.  The outputs from
the force gage and the two wave probes were recorded on paper
strip charts.  Also the output of the force gage was inte-
grated to'give the average drag.

At the start of a typical  test, the  sorbent material chips
were dumped into the center of the recovery platform, as
shown In Figure 60, and the harvesting conveyor, transfer
conveyor and broadcasting  systems were started'.  The towing
carriage then towed the model  down the tank at the desired
speed while the towing drag, wave height and relative motion
were recorded.  Also, pictures and observations were made
of the sorbent distribution and recovery.  After the first
test run of the day, the sorbent material was simply allowed
to remain in the recovery  platform.

In addition to the towing  tests, some tests were carried
out with the model pushed  by the towing carriage.  This was
to simulate the type of operation in which the recovery
platform Is pushed by a barge. The  pushing was done with
3 foot long steel arms pivoted at both ends.  In these tests,
no measurements were made  of pushing force.  This test set-
up is shown in Figure 60.

Towline Drag and Towing Stability

Towing tests of the sorbent recovery platform were carried
out over a range of speeds and sea states for the deployment
and nominal operating conditions.  The drafts and salt water
displacements for these conditions are:
           Condition           Draft          DlB£lacejnent

         Deployment            2' - 0" '        57,500 Ibs

         Nominal Operating    3' - 0"         80,000 Ibs
                             177

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            Adding Sorbent Material at Start of Test
                 Arrangement of Pushing Arms
FIGURE  60 - TEST SETUP FOR SORBENT RECOVERY PLATFORM
            MODEL
                          178

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Tests were conducted  in  long  crested  irregular waves  cor-
responding to Sea State  1  (significant  wave  height =1.1
ft) and a low Sea State  3  (significant  wave  height =  2.6 ft).

The significant wave  height is  defined  as  the average height
of the 1/3 highest  waves.

The towline  drag data were expanded to  the full  scale value
using Proude scaling.  Because  of the low  scale  ratio
 (\ = 4.0) and the bluff  shape of  the  body, no correction was
taade for changes in the  skin  friction in expanding the drag
data to full scale.   The resulting towline drag  for calm
water and waves over  the range  of speeds expected for sorbent
recovery are presented in  Figure  6l for the  deployment con-
dition.  Figure 62  presents the towline drag in  calm  water
for the deployment  condition  up to the  highest practical
 towing speed.  This speed  is  about 9-5  knots and is limited
 by excessive sinkage  the trim of  the  platform.   Figure 63
presents a photograph of the  model under tow at  a speed
 equivalent to 9.5 knots.   Figure 64  presents the towline
 drag for  the nominal  operating  condition over the expected
range of  speeds for sorbent recovery  in calm water and waves.

 The towline  drag data for  calm  water  were  also reduced to
 nondimensional  form so that they  can  be used to  estimate
 the drag  of  similar platforms of  different size.  The results
 are presented in Figure  65 in terms of  a towline drag coef-
 ficient as a function speed length ratio.  The drag coeffi-
 cient is  defined as:
 where
          D  =  towline drag,  ilbs
          p  =  mass density of water,  slug/ft3

          V  =  displaced volume of platform,  ft3,  and

          u  =  towing speed,  ft/sec.

 The speed length ratio is defined as:

                 Speed length ratio =
                             179

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 4000 -
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 1000 -
            DRAFT = 2' - 0"
            DISPLACEMENT = 57,500 Ibs
        CONDITION   SEA STATE  SIG. WAVE
                                HEIGHT
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             D        S.S. 1      1.1 ft
             A        S.S. 3"     2.6ft
    0
                            4.0        6.0
                           TOWING SPEED ft/sec
                            10.0
    0
                 1
  3
KNOTS
    FIGURE 61 - SORBENT RECOVERY PLATFORM DEPLOYMENT DRAFT
               TOWLINE DRAG Vs SPEED AND SEA STATE
                          180

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MAXIMUM PRACTICAL
TOWING SPEED-
              ^T 4.0   6~TOO  10.0  12.0  14.0  16.0  18.0  20.0
                             TOWING SPEED ft/sec
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          FIGURE 62 - iSORBENT RECOVERY PLATFORM DEPLOYMENT DRAFT
                     TOWLINE DRAG Vs SPEED
                                1.81

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FIGURE 63 -
SORBENT RECOVERY PLATFORM UNDER TOW AT
9.5  KNOTS
                       182

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7000
6000 -
                               DRAFT = 31 - 0"
                               DISPLACEMENT = 80,000 Ibs
0

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FIGURE 64 - SORBENT RECOVERY PLATFORM OPERATING DRAFT
          TOWLINE DRAG Vs SPEED AND SEA STATE
                          183

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SPEED LENGTH RATIO


  (SPEED IN KNOTS)
                                                      V,

                                                        -
                                                                  2 FT DRAFT
                                                                                I     t
1.5
                                                                                 2.0
                                  [LENGTH OF AFT PONTOON ( ft )J t




             FIGURE 65 - SORBENT RECOVERY PLATFORM DRAG COEFFICIENT VS. SPEED

                          LENGTH RATIO

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where

         VK  =  towing speed,  knots, and

         L   =  length of aft  pontoon,  ft.

The length of the aft pontoon  was  selected for the length
scale in the speed length ratio  since it is the longest
continuous component in the recovery platform.  The rise
in the drag coefficient above  a  speed length ratio of 1.2
indicates that energy is being dissipated in surface waves
as well as in form drag.

The towing stability was checked by giving the model a
lateral displacement as it was being towed down the tank.
The model rapidly returned to  its  original position directly
behind the towing point on the carriage.  This indicates the
platform has directional stability when under tow and thus
will tow satisfactorily without yawing.

Sorbent Broadcasting and Recovery

The sorbent broadcasting and recovery tests were conducted
for conditions equivalent to full-scale speeds of 3.0 and
6.0 ft/sec in calm water,, Sea  State 1 and a low Sea State  3.
The data obtained in these tests were qualitative in nature
and consisted of observations of performance supported by
still and motion pictures.  Typical photographs from the
test program are presented in Figures 66,  67 and 68.   All  of
the photographs are for a speed equivalent to 3 ft/sec full-
scale which is the nominal design  speed.  The range of sea
conditions from calm to a low  sea  state 3 are covered by the
photographs.  The important observations from the broad-
casting and recovery tests are presented below:

         1.  The sorbent distribution within the system is
             stable.  The tests showed that concentrations
             of sorbent material in the system tend to become
             spread out,, and that ultimately the sorbent dis-
             tribution throughout  the system tends to become
             uniform.  This is because of the broadcasting
             system which spreads  the sorbent over a  sub-
             stantial (about 20 feet) longitudinal distance
             as well as lateral distance.   As a  consequence
             of the stability of the sorbent distribution,
                            185

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FIGURE 66 -  RECOVERY PLATFORM OPERATING IN CALM WATER AT 3.0 ft/sec


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                     Broadcasting
               Harvesting and Transfer Conveyor
FIGURE 67 - RECOVERY PLATFORM OPERATING IN SEA STATE
            1  AT 3 ft/sec
                            187

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                Recovery Platform Being Towed
                                                     I
               Recovery Platform Being Pushed
FIGURE 68 - RECOVCK,' ?' *TFQRM OPERATING IN SEA STATE 3
            AT 3 ft/sec


-------
    it is possible to maintain a continuous sorbent
    broadcasting and recovery process without con-
    stant adjustments by the operating crew.

2.   The sorbent broadcasting and recovery"operation
    is not degraded by waves up to a low sea state
    3.  The tests showed that the broadcasting and
    recovery processes are not greatly effected by
    waves up to the height tested.  The freeboard
    and draft of the platform are sufficient to
    prevent sorbent loss due to waves breaking over
    or washing under the aft pontoons and harvesting
    conveyor.  The relative motion probe showed that
    relative motions in short waves do not greatly
    exceed the wave height and in moderate and long
    waves, the platform contours the waves with only
    small relative motions.  This is illustrated by
    relative motion data obtained in regular waves
    which are presented in Figure 69.  These data
    show that relative motions will be small in
    wavelengths equal to or greater than the plat-
    form overall length.

3.   The broadcasting nozzle developed in Task 2
    will provide a uniform distribution of sorbent
    over the width of the recovery platform.   These
    tests further confirmed the validity of the
    broadcasting nozzle concept developed in Task 2.
    The quality of the distribution pattern across
    the width of the recovery platform is illustrated
    in Figures 66 through 68.

4.   The sorbent material can be recovered by a
    harvesting conveyor half the overall sorbent
    pattern width.  During the tests, there were
    no indications that the sorbent material would
    form a bridge or plug across the inlet to  the
    harvesting conveyor.  In waves,  the inboard
    sides of the aft pontoons.reflect waves back to
    the center of the recovery bay.   These reflected
    waves tend to locally herd the sorbent material
    to the center of the harvesting conveyor.   Thus,
    in waves, there is no chance that the sorbent
    material could form a plug across the inlet  to
    the harvesting conveyor.
                   189

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  2.0
X
O
LU
X


<
I



§'•"
I—
o
               25
                         T
                                    T
                         FORWARD SPEED = 3.0 ft/sec

                         RELATIVE MOTION AT FOOT OF HARVESTING CONVEYOR
50         75

    WAVE LENGTH , feet
100
125
150
      FIGURE 69 - SORBENT RECOVERY PLATFORM RELATIVE MOTION IN

                  REGULAR WAVES
                                190

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Results

The important results of this developmental program can be
summarized  as follows:

      1.   The test program showed that a continuous sorbent
          broadcasting and recovery operation with a uniform
          stable distribution of sorbent material can be
          achieved.

      2.   The sorbent broadcasting and recovery operation
          was not degraded by waves up to a low sea state 3
          and forward speeds up to 6 ft/sec.

      3.   The broadcasting nozzle concept developed in
          Task 2 provided a uniform transverse distribution
      •    of sorbent material.

      4.   The sorbent material did not show any tendency to
          plug the inlet to the harvesting conveyor.

      5.   The recovery platform can be towed up to a speed
          of 9-5 knots in the deployment condition.

      6.   The recovery platform is directionally stable
          under tow.
                              191
 *US. GOVERNMENT PRINTING OFFICE: 1973 514-154/259 1-3

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1
Accession Number
w
5
j Subject Field & Group
05D
SELECTED WATER RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
organization
TTTrpl'O^MlTA Timi-/Nn -i- •
          	—	— — -*- •«••—- j  -J-i* Vw-j. £SW4. <-* U V\A

          Pindell School Road,  Laurel, Maryland   20810
          Development and  Preliminary Design of  a  Sorbent-Oil
          Recovery System
1 Q Authors)
IWM 1 ~\ p-p TH
rLL X -L OJL , Ju
Stephens,
Ricklis,
1
L.
J.
16

21
Project Designation
15080-HEV
Note
  22
     Citation
           Environmental Protection Agency report
           number, EPA-R2-73-156, January 1973.
 23
Descriptors (Starred First)
 *
   Oil Spills,  *Water Pollution Treatment,  *Design Criteria,
 ^Laboratory Tests
 25
Identifiers (Starred First)
      *Sorbent-Oil Recovery
 27
    Abstract
Abstract
 A development program was completed and preliminary designs  were pre-
 pared for  3000 gallon/hour protected water and  10,000 gallon/hour un-
 protected  water Sorbent Oil Recovery Systems.   The  five  phases  in the
 development  program were: (l) characterization  of the sorbent material,
 (2) the development of the sorbent broadcasting system,  (3)  the de-
 velopment  of the harvesting conveyor and evaluation of overall  re-
 covery performance, (4) the development of the  sorbent regeneration
 system and (5) model tests of a 1/4-scale model recovery platform.
 The development program showed that a continuous sorbent-oil recovery
 system is  feasible using 30 or 80 PPI polyurethane  sorbent chips.
 In one pass  about 90 percent of the oil in a 1.5 mm slick can be re-
 covered.   The water content of the Recovered Fluid  is  less than 10
 percent.   The preliminary designs are presented with detailed de-
 scriptions of the system components, operating  procedures, and  costs.
 This report  was submitted in fulfillment of Project Number 15080-HEV
 and Contract Number 68-01-0066 under the sponsorship of  the  Office of
 Research and Monitoring,  Environmental Protection Agency.
Abstract'
     I. Miller
                                    Inc. Laurel, Md.  (Miller-HYDRONAUTHS)
 WR:(02 (REV. JULY 1969)
 WRSIC
                        SEND, WITH COPY OF DOCUMENT,
                                         U.S. DEPARTMENT OF THE INTERIOR
                                         WASHINGTON, D. C. 20240
                                                                  * SPO! 1870-389-930

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