EPA-B2-I2-033
1872 Technoloit Siries
Air Modulated Vacuum
Oil Recovery Collection
of
3)
o
Office of Research and Monitoring
U.S. Environmental Protection Agency
Washington. D.C.
EPA M2-72-033
-------
RES MEG B REPORTING
Research reports of the Office of Research and
Monitoringt Environmental Protection Agency, have
been grouped into five series. These five broad
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was consciously planned to foster technology
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2m Environmental Protection Technology
3. Ecological Research
4. 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 %K>rk provides the new or improved
technology required for the control and treatment
of pollution sources to meet environmental quality
standards,.
-------
1PA-B2-72-033
August 19T2
MR OIL
COLLECTIOI OP HPILL1D OIL (FOAMS)
Project 15080 EHP
Project Officer
Clifford Risley
EPA - Region V
1 Uorth Waeker Drive
Chicago, Illinois 60606
Prepared for
01 AID
U.S. MVIROHMENTAL PROTECTION AGMCY
WASHINGTON/ D0C. 20460
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D,0. 20402 - Price 75 cents
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EPA Review Notice
This report has been reviewed by the Environmental
Protection Agency, and approved for publication.
Approval does not signify that the contents neces-
sarily reflect the views and policies of the En-
vironmental Protection Agency, nor does mention of
trade names or commercial products constitute en-
dorsement or recommendation for use.
ii
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ABSTRACT
A method of oil harvesting was developed involving the
air modulated vacuum oil recovery technique. The collec-
tion of thin oil slicks from water surfaces by the method
of oil foam generation and air modulation of vacuum oil
recovery was developed in an experimental and engineering
design project. This resulted through construction of a
prototype device which has proved capable of rapidly re-
covering thin slicks of oil from water surfaces. Very
little water is present in the recovered oil (<10% by
volume).
The range of application of vacuum oil recovery has been
successfully extended to thin oil slicks (<4 mm) through
the application of controlled air modulation and oil foam
generation. The prototype device was designed for remote
operation and hence possesses self contained power sources.
The two foot diameter prototype demonstrated performance
by treating 7500 gallons of oil and water in a test tank
in 4 minutes and recovering the oil at the rate of 450 gal/hr
from this very thin oil slick. Thicker slicks could be re-
covered much more rapidly.
The capabilities of treating much greater quantities of
oil/water by this prototype device are discussed.
This report was submitted in fulfillment of Project Number
15080EHP under the sponsorship of the Environmental Protec-
tion Agency and The City of Cleveland, Ohio.
111
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Page Intentionally Blank
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CONTENTS
Section Page
I Conclusions 1
II Recommendations 3
III Introduction 5
IV Experimental - Phase I 7
V Design Engineering and Working Model
Construction - Phase II 33
VI Discussion 49
VII Acknowledgements 55
VIII References 57
v
-------
FIGURES
Page
1 Bench Scale Apparatus 9
2 Apparatus for Examination of Oil/Water-to-
Aerator 18
3 Apparatus for Evaluation of Oil/Water Content
of Foams 19
4 Drawing of Oil Foam Collection Apparatus 22
5 Photograph of Bench Scale Apparatus for
Horizons' Air Modulated Vacuum Oil Recovery 23
6 Photograph of Apparatus after 1 Min. into
Experimental Recovery of an 8 mm Thick Slick
of Louisiana Crude Oil 23
7 Photograph of Foam Generation and Close-Up
of Vacuum Recovery Head 24
8 Photograph of Tank Surface Illustrating Manner
of Oil Removal by Experimental Apparatus 24
9 Schematic of Large Laboratory Scale Experiment 32
10 Nucleus of Air Modulated Vacuum Oil Recovery 35
11 Schematic of AMVOR Device and System Elements 36
12 Plan View of AMVOR Device 37
13 Schematic Diagram of Air Distribution Manifold 38
14 Schematic Diagram of System Control Elements 39
15 Plan View of Accessory Element. Vacuum
Reservoir and Air Ejector 40
16 Flow Regime Pattern in Device Vicinity 41
17 Floor Plan-Test Area 44
18 Photograph of AMVOR Device in Test Tank 45
19 Photograph of Oil Recovery Operation with
AMVOR Device (View A) 46
VI
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FIGURES (continued)
Page
20 Photograph of Oil Recovery Operation with
AMVOR (View B) 46
21 Plan of AiVOR Device in Field Operation with
Catamaran Work Boat 50
22 Oblique Aerial View of Cuyahoga River Valley
and Cleveland Harbor Showing Oil Accumulation 53
vii
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TABLES
MSLi_ Page
1 Surfactant Types 8
2a Foam Stability Tests on Oils 10
2b Foam Stability Tests on Heavy Louisiana Crude 11
2c Foam Stability Tests on Louisiana Crude Oil
+ Surfactants 12
2d Foam Stability Tests on Louisiana Crude +
Surfactants + Water 13
3 Effect of Surfactant Concentration on Foam
Properties 15
4 Examination of Effect of Oil/Water Interface
to Aerator Separation on Foaming Properties 17
5 Oil/Water Content of Foams 20
6 Oil Removal (1536-18). 25
7 Oil Removal (1536-13) 26
8 Oil Removal (1536-20) 27
9 Oil Removal (1536-23) 28
10 Oil Removal (1536-24) 29
11 Oil Removal (1536-41) 30
12 Oil Removal 31
13 Design Data 33
14 Results of AMVOR Device Oil Recovery Tests 43
15 Summary of AMVOR Device Specifications 51
Vlll
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SECTION I
CONCLUSIONS
An air modulated-vacuum oil recovery (AMVOR) system was
examined in laboratory studies. The goal of the system was
the development of a technique for the rapid recovery of
spilled oil with the aid of foam.
Laboratory tests were conducted to evaluate various oil
foam generating surfactants and water-oil systems. Sur-
factant materials were selected and studied under bench
scale conditions and individual criteria developed to rate
their effectiveness. Several of the systems were promising
on the small scale in that they produced very rich oil foams
that were recovered by simple vacuum recovery techniques.
Evaluation of these systems on a larger scale proved addi-
tionally promising and permitted the collection of design
data. Such data permitted the projection of the design of
the working model to be constructed in the second phase of
this program:
The results of this first phase experimental program may be
briefly summarized as follows:
1. Several oils were found to possess foaming
properties by themselves (See Table Ila).
2. Certain oil/water systems have shown foaming
properties.
3. A number of non-toxic surfactants have been
evaluated which enhance the foaming of the oil
in the presence of water and produce oil rich
foams. The surfactants which showed the most
promise in enhancing foam production were
n-amyl alcohol and 4-methyl 2 pentanol. These
are soluble in oil and insoluble in water and
hence will remain in the oil.
4. Most important of all, the foaming and recovery
of the oil by air-modulated vacuum suction has
shown very promising results as summarized in
Table V. In many cases the water content of the
recovered oil is well below the acceptable
limit of 10% water content. The recovery pro-
cess appears to be quite rapid.
Design, engineering, construction and testing were carried
out in the second phase of this program. The results of
testing of the completed device may be summarized as follows:
-------
1. The device performed very well in the case of
rapidly removing thin (<4 mm) oil slicks by
vacuum oil collecting and foam generation. The
vacuum recovery of the oil slicks proceeded
at the rate of 450 gal/hr of oil.
2. Water disturbances (due to water pump exhaust)
were encountered in the test tank and the de-
vice collected the oil at reasonable rates.
3. The oil collected in several experiments was
found to contain low water contents (<10%).
4. The performance of the device in the 18' test
tank indicates outstanding potential of the de-
vice for field testing.
5. The cost of the device as constructed under this
program is estimated to be $5,800,
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SECTION II
RECOMMENDATIONS
1. Further operation under field conditions is recom-
mended to demonstrate the performance of the device,
2. The economy of operation and rapidity of recovery
for thin oil slicks deserves further demonstration
on a larger scale.
3, The core of the present prototype was designed
for adaption to field testing. Therefore, it is
recommended that a catamaran be employed in the
first field testing of the device as depicted in
Figure 21.
4. The scale of testing should be such to reflect the
operation of such a device to handle chronic oil
spills in such waterways as the Cuyahoga River,
Houston ship channel, the Buffalo River, etc.
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Page Intentionally Blank
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SECTION III
INTRODUCTION
This report summarizes the program entitled "Air Modulated
Vacuum Oil Recovery - Collection of Spilled Oil with the
Aid of Foams", Program Number 18050EHP supported jointly
by the Environmental Protection Agency and the City of Cleve-
land and was conducted by Horizons Incorporated. The ex-
perimental laboratory phase of the program was from
October 19, 1969 to March 30, 1970. The design, construc-
tion and testing phase was from June 18, 1970 to
October 30, 1970.
The problem of oil spills is one which has been reviewed
and considered from many aspects. The objective of this
program was the development of a device to collect spilled
oil from the surface of water. The device embodied, as a
main principle, the trapping of the oil in a foam produced
by air agitation and a foaming agent, along with vacuum
collection of the foam and its breakdown to liquid oil. The
device was designed, constructed and tested in the form of
a working model in the second phase of the program. The
results of the tests on the model device show it to be an
unqualified success in providing a rapid method of recovering
thin oil slicks from water surfaces and extending the range
of application of the vacuum suction technique. It further
offers the potential of working in sea state conditions with
similar success due to the versatility of its design and
the counteraction of the main problem of straight vacuum
suction techniques under similar conditions. These considera-
tions will be discussed in greater detail later.
Various sources (1, 2, 3, 4, 5, 6) indicate that vacuum
suction devices plus containment offer advantages in low
cost of recovery operations and potentially rapid recovery
rates. However, a disadvantage of straight vacuum suction
is the lower limit of slick thickness (approximately 1/2
inch) which can be efficiently collected. Below this thick-
ness straight vacuum suction draws great quantities of water
into the collection tank. The value of the Air Modulated
Vacuum Oil Recovery (AMVOR) technique is that it surpasses
this limitation in removing oil and attains nearly quantita-
tive oil removal as a practical possibility.
The Horizons' Air Modulated Vacuum Oil Recovery (AMVOR)
System involves the trapping of the oil in a foam followed
by vacuum collection of the oil rich foam. Foaming aids
are employed, when needed, to enhance the conditions of in-
jection of fine diameter bubbles across the oil/water inter-
face. The stability of the foam generated is also enhanced
-------
by such agents. A suitable foam stability is needed to
permit gravity separation of the water from the oil foam.
The AMVOR technique has a broad range of application and
can be employed to treat emulsions of oil in water, also,
This is borne out by reference to studies of air flota-
tion as a method of treating hydrocarbon refinery wastes
(7S 83 9) and noting that air scrubbing of such an emulsion
condition can produce a froth which is removable by vacuum
techniques.
The experimental phase (Phase I) of the program involved a
demonstration of the feasibility of the approach and the
acquisition of data useful to the design phase (Phase II)
of the program. The experimental phase included an Investi-
gation of (a) foaming aids, (b) air dispersing techniques,
(c) oil foam collection, and (d) oil foam breaking.
The engineering phase (Phase II) involved engineering, con-
struction and testing the design of the model device. The
model embodies the main elements of a field scale device
and is seen to be readily adaptable to field operations as
a result of its successful tests. To permit remote field
operations with minimum hazard and cost, compressed air
power was selected as the unified power source. Compressed
air provided the motive air for vacuum generation, for pump
motor power, for actuator control elements, and for oil
foam generation. The system was divided into natural sub-
elements (or assemblies) selected for ease of maintenance
and to permit future remote operation. The total device
was designed to fail safe, to have reserve elements for
additional control of the system and to permit auto-opera-
tion of the system with minor attention from an operator.
The completed device was tested in a 7500 gal test tank with
a depth of four feet with thin tramp oil slick (<4 mm
thick). Such thin slicks are common on the Cuyahoga River,
for example, and additionally provide a stringent test for
the system. If such thin slicks can be recovered rapidly
from the described test tank, obviously thicker slicks can
be recovered much more rapidly. The results of the tests
demonstrate recovery rates' of 450 gal/hr.
6
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SECTION IV
EXPERIMENTAL - PHASE I
The laboratory phase of this program included the following
considerations:
1. Foaming Agents Investigation
2. Air Dispersing Techniques
3. Foam Collection
4. Foam Destruction
All of the above considerations were examined. The focus
of attention was primarily on the foaming agents and the
air dispersing technique. Several methods and conditions
of air dispersion were examined. Vacuum pickup of the oil
on the bench scale was not a problem and leads to a high
degree of foam destruction. The application of heat was
also useful in foam destruction. Bibuluous materials were
useful in collapse of the oil foam3 however, under the ex-
perimental conditions the vacuum collapse was more efficient,
It was our goal to produce highly expanded stable foams
containing minimum quantities of water, while utilizing low
concentrations of nontoxic biodegradable surfactants.
The initial criteria used for the basis of selection of
selection of surfactants are outlined as follows:
Initial Surfactant Criteria
1. Oil Solubility
2, Foaming Capability at Low Concentrations in Oil
a. Good expansion factor (ratio of foam
volume to contained liquid)
b. Good foam stability (long collapse time
in undisturbed condition)
3. Effective at Low Surfactant Concentrations
in Aqueous Environment
4. Non-enhancement of Oil Emulsion Formation
5. Nontoxic (or low toxicity)
6. Biodegradable
-------
Using these criteria we selected for laboratory study
commercially available surfactants which are used in
various food products and the petroleum industry. Also,
materials used in the dispersion treatment of oil slicks
were examined with respect to their foaming properties at
low concentrations.
Table 1 lists the type and name of the surfactants examined
in the preliminary laboratory evaluation. The laboratory
study consisted of a determination of the expansion height
achieved by low concentrations of surfactant in oil over
water. ThB sample was subjected to aeration by a given
volume of air at a standardized pressure and flow rate
through a porous disc below the oil/water interface. The
time required for the collapse of the foam to the initial
state was also determined in this confined container.
Timing of the collapse time was limited to a 3 minute
maximum to permit a rapid survey of surfactants. Figure 1
illustrates the foaming evaluation apparatus. Tests were
conducted on Heavy Sweet Louisiana Crude. Table 2 sum-
marizes the tests of aeration on the oils and oil/water
system.
TABLE 1
Surfactant Types
1. Soybean Phosphatides
"Lecithins"
2. Sorbitan Fatty Acid Esters
Arlacel 20 (Sorbitan Monolaurate)
Arlacel 80 (Sorbitan Monooleate)
3. Polyoxyethylene Sorbitan Fatty Acid Esters
Tween 60 (Polyoxyethylene (20) Sorbitan Monostearate)
4, Polyoxyethylene Sorbitol Esters
5. Polyoxyethylene Alcohols
Brij 58 (Polyoxyethylene (20) Cetyl Ether)
6. Tergitol Nonionics
Nonyl Phenyl Ethyleneoxide
Nonionic NP-14
7. Rosin Derivatives
8. Commercial Materials for Oil Spill Treatment
Gamlen Tyaflo
Slix OSD
Spillaway Magnus
9. Aliphatic Alcohols
n-amyl alcohol isopropyl alcohol
4-methyl 2 pentan-ol methyl alcohol
ethyl alcohol
-------
Expansion
Height
X
Foam
Oil
Water
V// /////// 77777
Air
Porous Disc
(4.0 cm diameter)
Medium porosity
Nominal maximum
Pore diameter 10-15
microns
Air Flow Rates:
-i
a. 100 ml-min_1
b. 400 ml>min~_1
c. 1600 ml-min~
FIGURE 1
Bench Scale Test Apparatus
9
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TABLE 2a
Foam Stability Tests on Oils
Height Rise, Xn
Collapse Time, tn
n = flow units of air
1 = 100 ml.min":
2 = 400 ml-min~
5 = 1600 ml-min"
Canadian
Crude (CC)
xl
(cm)
4
(sec)
26
X2
(cm)
8
(sec)
31
x5
(cm)
12.5
(sec)
32
Illinois
Basin (IB)
Heavy
Louisiana
Crude (HLC)
Sw. Louisiana
Crude (SLC)
5.5
6.5
5.0
60 10
45
50
9.0
8.0
62
59
60
11.0
10.0
9.5
60
60
60
Sw. Louisiana
Crude
Foam Stability Tests on Oil + Water
no foam 7.0 90 7.5 50
Illinois Basin froth (-1/2 cm) froth *15.0 32
froth froth *11.0 25
Canadian
Crude
Foaming occurs when oil comes in contact with air in-
jector.
10
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TABLE 2b
Foam Stability Tests on Heavy Louisiana Crude
Surfactant
Cone.
%
PE 40
.25
.50
1.0
P 400
Polypropylene
Glycol
.25
.50
1.0
N-amyl
Alcohol
.25
.50
1.0
Slix
.25
.50
1.0
Spillaway
.25
.50
1.0
EHEC (low)
.25
.50
1.0
Xl
(cm)
6.0
7.0
7.0
7.5
6.0
7.0
6.5
6.0
6.0
7.0
7.0
7.0
7.5
7.5
6.5
8.0
8.0
6.0
*1
(sec)
42
40
45
76
70
60
42
48
43
50
48
55
79
60
40
49
46
45
X2
(cm)
7.0
7.5
7.5
7.5
7.0
7.5
6.5
7.5
7.0
7.5
7.0
7.0
7.0
7.5
7.0
7.5
7.0
7.0
*2
(sec)
50
50
50
75
70
70
48
58
60
60
48
60
60
60
50
50
48
60
X5
(cm)
8.0
8.0
8.5
7.5
8.0
8.0
8.0
8.5
8.0
8.0
8.5
7.5
7.5
8.5
7.0
8.0
7.0
8.0
*5
(sec)
57
60
56
70
72
70
58
60
58
70
70
70
65
68
40
50
59
60
11
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TABLE 2c
Foam Stability Tests on
Louisiana Crude Oil + Surfactants
Heavy
Louisiana
Crude
1
(cm)
6.5
1
(sec)
45
2
(cm)
9.0
2
(sec)
59
5
(cm)
10.1
5
(sec)
60
Surfactant
Cone.
Aerosol 18
.25
.50
1.0
Arlacel 20
.25
.50
1.0
Arlacel 60
.25
.50
1.0
OSD
.25
.50
1.0
incompletely di
6.0
9.5
11,0
45 6.5
60 8.5
60 10.5
(Sorbitan Monolaurate)
7.5 180+*
8.5 180+
7.0 180+
4.5
5.0
4.0
3.5
5.0
5.0
28
35
22
25
35
50
8.0
8.5
7.5
5.5
6.5
5.0
7.5
8.5
9.5
Hyonic JN-400-SA
.25
.50
1.0
PI 225
.25
.50
1.0
4.0
4.0
5.0
7.5
7.5
8.0
30
30
60
45
75
54
5.0
4.5
6.0
7.5
7.5
7.0
45
50
50
180
180
180
35
40
35
50
43
50
30
30
60
45
45
51
6.0
8.0
9.0
8.0
7.0
8.0
6.5
6.5
6.0
8.5
9.5
9.5
6.0
5.5
6.5
8.0
8.0
7.5
40
45
50
180^
18 0
18 0
+
40
45
45
60
60
60
30
30
30
50
65
55
c
Three minutes was the limit used in timing the collapse time,
12
-------
TABLE 2d
Foam Stability Tests on Louisiana Crude + Surfactants
+ Water. 25 ml Oil + Surfactant = 25 ml Water
Surfactant „
Cone . 1
% (cm)
*1
(sec)
X2
(cm)
t2
(sec)
Xc
(cm)
t.
(sec)
Arlacel 20 (Sorbitan Monolaurate)
1.0
no foam
water dispersed
into oil 25-50%
dispersion
100%
dispersion
Spillaway
.25
.50
1.0
no foam no foam
no foam little foam
oil in large globules
air/water globules moving
around
7.0 50
7.0 40
small globules
some foam
Tergitol NP14 (Nonionic)(Nonyl Phenyl Polyethylene Glycol Ether)
1.0 no foam no foam 7.5 123
dispersion
formed/separated
but water cloudy
Arlacel 80 (Sorbitan Monooleate)
1.0 no foam
6.0 240"
some foam
remaining
Brij 98 (Polyoxyethylene (20) Oleyl Ether)
1.0 slight foam 7.5 60
broke system in-
to small globules
7.0
9.0
60
180
EHEC (low)(Ithyl Hydroxy Ethyl Cellulose)
.25
.50
1.0
no foam
no foam
no foam
no foam 8.0 64
6.0 55 7.0 65
9.0 43 7.5 60
Slix
.25
.50
1.0
no foam
no foam
no foam
no foam
9.0 45
9,0 76
9.0 75
dispersion
stable after
foam collapse
13
-------
TABLE 2d (continued)
Cone,
Xl
(cm)
(sec)
X2
(cm)
(sec)
x5
(cm)
%
(sec)
N-amyl Alcohol
.25 froth on surface 6.5 19 12,0 50
.50 6.0 16 7.5 37 9.0 57
1.0 6.0 10 6.5 22 9.0 50
injection of air bubbles occurred through the oil/water
interface
Polypropylene Glycol P400
.25
.50
1.0
froth
froth
froth
froth
froth
froth
6.0
6.5
6.5
20
20
25
6.5
10.0
11.0
45
44
39
Hyonic P40
.25
.50
1.0
no foam
no foam
no foam
9.0 64 9.5 150
8.0 55 9.5 169
9.0 55 9.0 132
dispersion foams
Hyonic P225
.25
.50
1.0
5.0 14
froth
6.0 20
6.0 27 8.5 72
froth 8.0 120
8.0 61 8.0 70
foam above dispersion
Hyonic JN-400SA
.25 7.0
.50
1.0
6.0
7.0
67
34
60
12.5
90^
11.0 90
15.0 180
14.0 90
water
foam
A large number of surfactants have been examined at several
concentrations (0.25, 0.5 and 1.0 weight percent surfactant/
oil) at various aeration rates. The most promising
materials were studied further at lower concentrations
(0.1, 0.01, and 0.001 weight percent) to determine varia-
tions of effectiveness. These experiments are summarized
in Table III. The surfactants were selected for further
study at lower concentrations based on the following con-
siderations of the foams they produced:
14
-------
1. The collapse times of the foams were in ex-
cess of 90 seconds.
or 2. The foams were formed in the aqueous system
and the surfactant did not produce exces-
sively stable oil/water dispersions and the
foams were more stable than the dispersions.
or 3. The foams tended to be rich in oil or had
other interesting properties.
TABLE 3
Effect of Surfactant Concentration on Foam Properties
Surfactant
Cone.
%
X
1
(cm)
t
1
(sec)
x
2
(cm)
t
2
(sec)
x
5
(cm)
t
5
(sec)
Brij 30
1.0
.5
.25
.1
.01
.001
21.0 300
5.5 180
no foam
no foam
no foam
no foam
23.0 ISO"1" 25.0 240"
20.0 180 20.0 180
6.0 20 19.0 180
8.0 32 9.5 55
no foam 8.0 20
no foam 9.5 51
Brij 76
1.0
.5
.25
.1
.01
.001
16 ,0
5.0
7.0
8.5
5.0
180"
30
20
56
froth
no foam
31.0 180^
10.0 180
13.0 112
11.0 90
6.5 17
no foam
45-25
11.0
12.0
9.0
7.5
10.0
180];
18 0+
18 0+
126
27
50
Brij 96
1
.0
,5
.25
.1
.01
.001
12.5 180"
10.0 180
8.0 180H
no foam
no foam
no foam
25.0
25.0
25.0
10.0
7.0
180
180
180
60
30
no foam
too high (>25 cm)
to measure in
apparatus
9.5 108
9.5 78
7.0 10
G-1086
.0
.5
.25
.1
.01
.001
8.0
6.0
8.0
6.0
180"
150
150
8
no foam
no foam
22.0 180+ 15.0
16.0 120 24.0
15.0 180+ 17.5
8.5 35 10.0
no foam 7.0
7.5 30 8.0
180
180
180
90
20
21
15
-------
TABLE 3 (continued)
Surfactant
Cone.
G-3634
1.0
1
(cm)
5.5
(sec)
20
(cm)
13
.0
(sec)
18 0+
5 5
(cm) (sec)
too
for
large
large
18 0+
column
.5
.25
.1
.01
.001
N-amyl Alcohol
1.0
.5
.25
.1
.01
.001
no
no
no
no
no
5.0
5.0
5.0
no
no
5.0
foam
foam
foam
foam
foam
froth
froth
froth
foam
foam
froth
8
5
5
7
6
7
.0
.5
.0
.5
.5
.0
54
10
froth
24
13
22
froth
froth
no foam
7
5
.0
.0
40
froth
15.
7.
8.
7,
10.
12.
8.
12.
11.
13.
12.
0
0
0
0
5
0
0
0
0
0
5
90
10*
<5
16
22
16
22
18
37
35
35
Tyfosol 80 (Amine-Amido Sulphonates and Alkanolamide Type
Surface Active Detergents)
1.0
12.0 ISO"*" 22.0 180 exceeded
column volume
-,« " 180
18 0+
17**
13**
23
61
41
62
37
29
.5
.25
.1
.01
.001
Klucel E
1
.0
.5
.25
.1
.01
.001
9
6
5
.0
.0
.0
no
no
(Hydroxylpropyl
5
7
5
5
.0
.5
.5
.0
no
no
18 0T
180+
foam
foam
froth
12.
9.
5.
5.
7.
0
0
0
0
0
180
180
froth
froth
21
17
14
8
7
9
.0
.0
.0
.5
.5
Cellulose)
froth
24
24
froth
foam
foam
8.
11.
10.
6.
7.
0
0
0
5
0
no
37+
froth
51
74
9
13
foam
14
16
15
15
10
w
.0
.0
.0
.0
.0
at
Froth: formation of a foam layer less than .1 cm in height,
At low extremes the foam does not completely cover
the oil surface.
*
dropped to 5 cm and held.
stable froth.
16
-------
The low concentrations of surfactant produced less foam
than the 0.25 weight percent solutions and required higher
air flow rates to generate foam.
Studies were also initiated on the method of aeration;
namely, the effect of variation in the separation distance
between aerator surface and oil-water interface. Figure 2
illustrates the experimental apparatus used in this study.
There appears to be an optimum distance required for maxi-
mum foam generation which is dependent upon the flow rate.
Thus3 it appears that low air flow rates require a closer
approach of aerator to interface while higher air flow
rates have optimum distances further away from the inter-
face as illustrated by the results of Table 4.
TABLE 4
Examination of Effect of Oil/Water Interface
to Aerator Separation on Foaming Properties
Interface-Aerator
Separation
Distance
(cm)
Unit
Aerator Flow Bates
2 Units
Foam
Height Collapse
Rise Time
(cm)
(sec)
X2
(cm)
5 Units
(sec) (cm) (sec)
5.5
4.0
3.0
2.0
2.0
2.0
2.5
3.5
30
30
60
75
4.0
4.0
6.0
4.0
45
48
85
59
9.0
12.5
11.0
5.5
80
90
85
58
Using this apparatus, a series of experiments was conducted
which investigated the removal of the oil foam by suction
and collected data which evaluated the water content of the
foam in a series of three foaming/suction steps for a given
quantity of oil. In these experiments, three liters of
water were placed in the column depicted in Figure 3.
17
-------
xn Foam
Height
\\TAT\TV\\\TT\\\\
Porous
Disc 8.0 cm dia.
Medium porosity
Nominal pore dia.
10-15 microns
8 mm Oil Layer
Y Variable Distance
Air Flow Rates:
n = flow units
1 = 100 ml-win
2 = 400 ml-min
5 = 1600 ml-min
-i
-i
-ml
FIGURE 2
Apparatus for Examination of Oil/Water-to-Aerator,
Separation Distance, Y
18
-------
Foam Height
4.0 cm
Porous Dise-
8.0 cm dia.
Medium porosity
Nominal pore dia
10-15 microns
Oil Foam Collected
in Centrifuge Bulbs
Initial 8 mm
Oil Layer
2 cm
Test Conditions:
3.0 1 H20
59 ml (50 g) oil
0.5% surfactant
30 sec. aeration (800 ml air)
Air
FIGURE 3
Apparatus for Evaluation of Oil/Water Content of Foams
19
-------
The aerator was placed 2 cm below the interface of oil/water,
Fifty grams of oil containing 0.5% surfactant were placed
in the column (oil layer 9 mm thick) and exposed to 800 ml
air over a foaming period of 30 seconds. The foam rose to
a height of 4,0 cm and was collected (after aeration was
stopped) by means of an inverted funnel. The sample was
collected in a centrifuge tube; the collection system was
rinsed with 25 ml of benzene and a determination of water
content was made according to AST! D96-52T. From the re-
sults shown in Table 5, one can see in the first aeration
(30 seconds) followed by suction that one can routinely
collect more than 40% of the oil in the slick over the
aerator and as much as 78% on the first cycle. Also, it
is apparent that after only three such aeration-suction
cycles more than 85% of the oil can be recovered.
^•-i/w 4- n 4. * * -GI
Oil/Water Content of Foams
TABLE 5
Oil (% Total Oil
)
ml Water(% Water in Sample)
Original Sample of Oil = 59 ml
Tes_t
I 29.1 ml
0.9 ml
II 29.3 ml
(49.3%)
"( 3% )
(49.6%)
7.0
3.0
19.0
(11.9%)
( 30% )
(32.2%)
20
30
3.5
(34%)
(60%)
(5.9%)
0.75
T273JET
1.0
1.5
(30% )
III
29.2 ml (49.5%) 12.3 (20.9%)
.85
(278%)
.7
(15%)
IV
24.3ml
.7
(41%)
(2.8%)
(14%)
(15%)
13.7
(23.2% )
..3 (8.7%)
46.1 ml
.9
(78% )
"(1.8%)
(14%)
(8.5%)
Average
53.4% total oil
Percentages 2.6%water content
18.6%
14.1%
17 '
J- * .«
3177%
89.3% average percentage of total oil recovered.
20
-------
A number of large bench scale experiments were conducted in
which slicks of 8 nun thickness were removed from the water
surface. Such experiments examined the conditions of
removal with various surfactants, determined the rate of
oil recovery with various surfactants, and analyzed the
oil recovered for water content.
The experimental apparatus employed in this series of ex-
periments is depicted in the drawing of Figure 4. Here the
main components of porous disc aerator, suction heads oil
drain line, vacuum line, and oil reservoir are represented.
The next series of four photographs, Figures 5 through 8,
respectively, depict (a) initial conditions, (b) experimen-
tal operation, (c) a close-up of oil foam generation and
collection, and (d) the surface of water at the conclusion
of the experiment.
It must be pointed out that the suction head is always
maintained in a position well above the oil/water inter-
face and that the generated oil foam rises into the suc-
tion head. Thus, the oil foam is drawn into the oil drain
line with very little water. The very low water content
of the recovered oil in the first fractions is extremely
important since this offers the potential of recovering
valuable oil material in a highly efficient manner and
possibly without further extensive treatment.
This is borne out by examination of several tables of data
(Tables 6 through 11) obtained by analysis of the various
recovered oil fractions for water content. Here, one can
see that with 8 mm slicks about 60% of the oil can be re-
covered with less than 0.5% by volume water. Conceivably,
if one is able to maintain the slick thickness at better
than 4 mm (~0.16 in.) thickness this recovery condition
may be maintained for the bulk of recovery operations.
Other straight vacuum skimming techniques require oil
slick thicknesses four times as great to be less effective
(1, 2). Similarly, examination of Table 11 where thicker
slicks (16 mm or ~.63 in.) were studied shows nearly 99%
of the oil recovered with less than 5% (by volume) water
content.
Table 12 presents the estimated analysis on a tramp oil
(Bunker C type) recovered from the Cuyahoga River which
was treated by the AMVOR apparatus in our laboratory. This
illustrates the range of application of the technique to
high viscosity oils.
Additional testing of the system concept in a larger labora-
tory scale involved employing the same sparging and recovery
elements (described in bench scale experiments) now in con-
junction with a large tank and larger vacuum oil recovery lines
21
-------
FIGURE 4
Drawing of Oil Foam Collection
Apparatus (Air Modulated Vacuum Oil
Recovery Apparatus)
22
-------
FIGURE 5. Photograph of Bench Scale Apparatus for Horizons'
Air Modulated Vacuum Oil Recovery
FIGURE 6. Photograph of Apparatus after 1 Man. into
Experimental Recovery of an 8 mm Thick Slick
of Louisiana Crude Oil
23
-------
FIGURE 7. Photograph of Foam Generation and Close-Up of
Vacuum Recovery Head
FIGURE 8. Photograph of Tank Surface Illustrating Manner
of Oil Removal by Experimental Apparatus
24
-------
This experimental apparatus is depicted in Figure 9. Ex-
periments on a 3 gal. oil slick showed that with the larger
drain line and the same pumping system, we obtained collec-
tion rates of 12 gal«hr~ . (Our previous rate was 2 gph.)
This permitted an upgrading of our design parameters and
indicated that higher efficiency of collection was possible
with less costly equipment.
TABLE 6
Oil Removal (1536-18)
8 mm Slick/5 Gal. Tank
(-500 ml Oil)
Oil Slick
Thickness
Remaining
(mm)
Initial 8
Fraction 1 4
2 ~1
3
Oil Elapsed
Collected % Total Collection % Water
Per Fraction Oil Time in
(ml) Collected (min.) Fraction
0
318 63.6 5.5 0.3
154 94.4 10.0 7.9
27 99.7 15.4 89.1
Experimental Conditions:
Aerator Porosity
Air Flow
Line Pressure
Bubble Diameter
Active Area (aerator area)
10-15 microns
2
1.6 1 air/min. (32 ml/cm -min.)
5 psi
<.5 mm (mainly ~,2 mm)
~8 sq. in.
Heavy Sweet Louisiana Crude Oil
0.5% n-amyl alcohol
25
-------
TABLE 7
Oil Removal (1536-13)
8 mm slick/5 Gal.Tank
(-500 ml Oil)
Initial
Fraction
Oil Slick
Thickness
Remaining
(mm)
8
1 4-5
2 <1
3 —
Oil
Collected
Per Fraction
(ml)
-
258
194
24
% Total
Oil
Collected
_
51.5
90.4
95.1
Elapsed
Collection
Time
(min. )
0
7.8
17.3
20.7
% Water
in
Fraction
-
0.0
2.0
68.3
Experimental Conditions:
Aerator Porosity
Air Flow
Line Pressure
Bubble Diameter
Active Area
10-15 microns
1,6 1 air/min. (32 ml/cm -min.)
5 psi
<.5 mm (mainly ~,2 mm)
~8 sq. in.
Heavy Sweet Louisiana Crude Oil
0.5% oc -terpineol
26
-------
TABLE 8
Oil Removal (1536-20)
8 mm Slick/5 Gal. Tank
(-500 ml Oil)
Oil Slick Oil Elapsed
Thickness Collected % Total Collection % Water
Remaining Per Fraction Oil Time in
(mm) (ml) Collected (min.) Fraction
Initial
Fraction
8
1 4
2 <1
3
-
308
158
18
_
61
93
96
.7
.3
.9
0
3
6
9
.0
.2
.2
0
2
90
_
.17
.2
.4
Experimental Conditions:
Aerator Porosity
Air Flow
Line Pressure
Bubble Diameter
Active Area
10-15 microns
1.6 1 air/min. (32 ml/cm2-min. )
5 psi
<.5 mm (mainly ~.2 mm)
~8 sq, in.
Heavy Sweet Louisiana Crude Oil
0.5% 4-methyl 2-pentan-ol
27
-------
TABLE 9
Oil Removal (1536-23)
8 mm Slick/5 Gal. Tank
(-500 ml Oil)
Oil Slick Oil
Thickness Collected
Elapsed
% Total Collection
Remaining Per Fraction Oil Time
(mm) (ml) Collected (min.)
Initial 8.0
Fraction 1 4.5 311
2 1.0 144
3 10
0
62.3 4.1
91.0 6.3
92.9 8.7
% Water
in
Fraction
_
0.5
39.3
95,1
Experimental Conditions:
Aerator Porosity
Air Flow
Line Pressure
Bubble Diameter
Active Area
10-15 microns
1.6 1 air/min. (32 ml/em2-min.)
5 psi
<.5 mm (mainly ~.2 mm)
~8 sq. in.
Heavy Sweet Louisiana Crude Oil
0.2% 4-methyl 2-pentan-ol
28
-------
TABLE 10
Oil Removal (1536-24)
8 mm Slick/5 Gal.Tank
(-500 mm Oil)
Oil Slick Oil
Elapsed
Thickness Collected % Total
Remaining Per Fraction Oil
(mm) (ml) Collected
Initial 8
Fraction 1 4 301 60.3
2 <1 144 89.1
3 - 15 92.2
Collection % Water
Time in
(min.) Fraction
0
4.2 0
7.45 2.7
8.85 83.5
Experimental Conditions:
Aerator Porosity
Air Flow
Line Pressure
Bubble Diameter
Active Area
10-15 microns
1.6 1 air/min. (32 ml/cm2-min.)
5 psi
<.5 mm (mainly ~.2 mm)
—8 sq. in.
Heavy Sweet Louisiana Crude Oil
1% 4-methyl 2-pentan-ol
29
-------
TABLE 11
Oil Removal (1536-41)
16 mm Slick/5 Gal. Tank
(-1000 ml Oil)
Oil Slick Oil
Thickness Collected % Total
Remaining Per Fraction Oil
(mm) (ml) Collected
Elapsed
Collection % Water
Time in
(min.) Fraction
Initial
Fraction
16
1 3
2 1
3 —
-
876
112
12
_
87
98
~100
.6
.8
.0
0
2
7
10
.5
.5
.9
5
2
95
-
.4*
.6
.2
This value is partly due to induced "wave action" distur-
bances in the first part of the experiment and the carry-
over of water as a result.
Experimental Conditions:
Aerator Porosity
Air Flow
Line Pressure
Bubble Diameter
Active Area
10-15 microns
1.6 1 air/min. (32 ml/cm2-min.)
5 psi
<,5 mm (mainly ~.2 mm)
~8 sq. in.
Heavy Sweet Louisiana Crude Oil
0.5% n-amyl alcohol
30
-------
TABLE 12
Oil Removal
8 mm Slick/5 Gal.Tank
(-1000 ml Oil)
Oil Slick Oil Elapsed
Thickness Collected % Total Collection % Water
Remaining Per Fraction Oil Time in
(mm) (ml) Collected (min.) Fraction
Initial
Fraction
16
1 4
2 —
-
800
150
_
80
95
0
8.1
10-12
™
4
50
Experimental Conditions:
Aerator Porosity
Air Flow
Line Pressure
Bubble Diameter
Active Area
Bunker "C" Tramp Oil
0.5% n-amyl alcohol
10-15 microns
1.6 1 air/min* (32 ml/cm2-min.)
5 psi
<.5 mm (mainly ~.2 mm)
~8 sq. in.
31
-------
Vacuum
w
tO
ca
o
ffi
3
P
CO f+
O H-
P O
(_j
CD O
Hs
•O p
CD 4
H- CD
3
B P3
rt- 0*
H-
O
O
CJ
4 r
3" Oil \
\/ Recovery Line ^
—J\»Iglass drain
line)
Oil Pumped
to Storage
Oil Collection
Reservoir
Flexible Hose
Standard Recovery Head
erator
125 Gal Tank
-------
SECTION V
DESIGN ENGINEERING AND WORKING MODEL CONSTRUCTION
PHASE II
The second phase of the program involved the design,
engineering, construction, and testing of a working model
of the air modulated vacuum oil recovery technique demon-
strated in the experimental phase of the program.
The design of the device was guided by several considera-
tions . (aj) The model should embody the main elements of a
field scale device, (b) it should permit ready transport,
portability (by standard conveyances), and (c) should permit
remote operation with minor attention of an operator on
heavily trafficked rivers, such as the Cuyahoga. With these
general factors in mind, the data acquired through the
laboratory phase was used to set certain goals for opera-
tional conditions of the device. The design data is out-
lined briefly in Table 13.
TABLE 13
Design Data
Laboratory Apparatus: 5 gal tank/aerator system
8 mm Thick Oil Slick
Air Sparging Rate: 1.6 1/min. (0.057 cfm)
Vacuum Requirements: 17.8 cfm
Oil Recovery Rate: 2 gph
Projected Apparatus: 100 gph oil pickup
Assume an oil foam expansion factor of 10 and collapse
time of 1 minute.
Also, assume 4 x foam volume = air volume required.
Air Sparging Rate: 9 cfm
Vacuum Requirements: 890 cfm
Additional Design Elements:
1. Oil Slick Feed System - Hydraulic
2. Recovered Oil Pump System
33
-------
As an initial consideration, to permit remote field opera-
tions with minimum hazard (due to handling liquid fuels
such as gasoline) and cost, compressed air power was
selected as the unified power source. Compressed air pro-
vided the motive air for vacuum generation, for pump motor
power, for actuator control elements, for flotation trim-
ming, and for oil foam generation. The system was divided
into natural sub-assemblies for ease of construction and
sub-assembly testing and debugging. The nucleus of the
AMVOR device was constructed first. This is illustrated in
Figure 10. It consists of a sparger, a vacuum suction oil
foam recovery head, and means to remove water (a 2" dia-
phragm pump). This sub-assembly was tested and proved out
by oil recovery from tank depicted in Figure 10.
A schematic of the entire oil recovery system is presented
in Figure 11. Briefly, the system consists of (a) a
portable air compressor, powered by LP gas, (b) an air
distribution manifold (see Figure 13), (c) a vacuum genera-
tion element (see Figure 15), (d) a sparger for foam
generating, (e) a level control system (see Figure 14),
(f) compressed air driven pumps, (g) a hydrodynamic flow
regime system (see Figure 16), (h) an oil transfer pump and
storage tanks.
Figure 12 presents a plan view of the device and identifies
the several elements of the system. (a) sparger (oil foam
generator), (b) vacuum pickup head, (c) actuators for wier
control, (d) the flow regime system, (e) central tank level
detector, and (f) bridge.
Sparger. The sparger consists of a porous stainless steel
disc (TOp, mean pore size) mounted at the end of air supply
line delivering 5-10 psi air at a rate of ~32 ml min cm" ,
A filter is employed to remove any particles which might
filter out at the sparger. The sparger is mounted in a
manner to permit adjustment of its position relative to the
interface oil oil and water.
Vacuum Recovery Head. The vacuum recovery head is construc-
ted of a special design to provide a venturi action among a
nested set of funnels with helical ribs to promote rapid
lifting of oil foam. The vacuum recovery occurs with a
rapid breakdown of the oil foam. The recovery head is
mounted on a rack and pinion to permit easy adjustment of
the recovery head above the oil surface (see Figure 12).
The vacuum generator is illustrated in Figure 15.
Actuated Wier Control. A circular wier is employed around
the central tank to permit adjustment of the oil flow into
the control tank. The wier is adjusted vertically with
respect to the bridge surface to allow a matching of the
34
-------
Oil
Oil and Water
Movable
Wier
t
Air
Vacuum
V
Vacuum Pickup
Head
t
Stainless
c3—
Steel Sparger
(6" diameter)
Air
Water Eemoval
HoO
Flexible
Boot
36" diameter tank
FIGURE 10
Nucleus of Air Modulated Vacuum Oil Recovery
35
-------
Air
Compressor
Distribution
Manifold
Vacuum
Generator
Vacuum
Receiver
Oil
Collection
Sump
Water
Removal
Pump
Level
Detector
FIGURE 11
Schematic of 1MVOR Device and System Elements
36
-------
Vacuum Recovery Head
Rack and Pinion
Adjustment
\
>. Flow Regime
S Water Inlets
Air
Oil (Vac)
Control
Lines
2" Diaphragm Pump
Uevel Detector
Flow Exhaust
Regime
Pump
H20
Exhaust
FIGURE 12
Plan View of AMVOR Device
37
-------
Filter
Jj] Regulator
Fj7j Lubricator
Globe
Valve
OH
/q I Gate
Vacuum
Ejector
Valve
Shut-Off
Valve
l Needle
" Valve
Gauge
Actuator
on Valve
o
-p
R
80
Exhaust
Exhaust
Ballast
Drum
Compressed
Air
100 psi
— >
K
Oil
Transfer
Pump
3"
Water
Pump
o-
2"
Water
Pump
FIGURE 13
Schematic Diagram of Air Distribution Manifold
38
-------
50 psi
White
Bluo
Controller
Hand/Auto
Station with
Adjustable
Set Point
Trans-
mitter
Level
Detectoi
Snap
Acting
Relay
Compressed
Air
R
Exhaust
Drum
Ballast
2" Pump
Activator
ixh
Pressure
Drum
Ballast
FIGURE 14
Schematic Diagram of System Control Elements
39
-------
80 psi Air
20-80 cfm
Exhaust
2" Line
Vacuum
from
AMVOR
Device
Impinger
Plate
Oil Recovered as
Collapsed Oil Foam
Oil Pumped
to Storage
FIGURE 15
Plan View of Accessory Element, Vacuum Reservoir and Air Ejector
40
-------
Oil-Water
1
, £
V
j
f/1
f~*
i
r
. ^
H20
%-
H-O
Flow Regime Head
HoO
^-. Water Pickup Heads
(^/Located Beneath Water
Surface Increasing
(O Area of Q)
1 \
H20<1
FIGURE 16
Flow Regime Pattern in Device Vicinity
41
-------
oil/water inflow with the water pumped from the bottom of
the tank and the oil foam removal. The central tank also
provides a relatively quiet area for the foaming and vacuum
recovery. The wier permits a controlled concentration of
the oil from the outside surface. The difference in water
levels in central tank and water surface provides a gradient
for oil movement to take place. This gradient is further
enhanced by the action of a flow gradient in a hydrodynamic
flow regime.
The Flow Regime System. The flow regime system consists of
a large capacity pump placed in one of the stabilizing
tanks adjacent to the central tank. The piping of the
pickup heads is depicted in the top view of Figure 12. The
piping additionally serves as support structure for the de-
vice. The piping terminates in 4 water pickup heads located
2-3 in. below the water surface to establish a flow gradient
in the direction of the central tank. The exhaust of the
flow regime is directed to permit further concentration of
the oil (see Figure 16).
Level Detector. The level detector is a differential pres-
sure transmitter which senses the variation in pressure
against a flexible diaphragm in a pneumatic column. The
variation is caused by changes in level of water/oil in the
central tank of the recovery device - and is depicted in
Figure 11. The differential pressure transmitter is air
powered and sends a signal to the auto/hand set point con-
troller which provides control signals to activate the pump
which drains the central tank. If for example, a large
wave of water/oil suddently enters the central tank the
pressure transmitter sends a proportional signal to the con-
troller and then to the pump telling it to increase speed
of pumping. Also, as back up to this system a buoyant float
is used to sense major changes of level and activate the
wier to close (that is, lift) or prevent (momentarily)
further water/oil inflow. The buoyant float trips a whisker
valve which bleeds an air line to the snap acting relay.
When the pressure is slightly reduced the relay trips and
air supply to the actuators is shut off. The springs of
the actuators then lift the wier and close off water flow.
Thus, the system "fails-safe" in the situation of loss of
air power or in the case of large water disturbances into
the central tank.
BrjLdge. The bridge of the device serves as the level
reference point and the area for mounting the actuators
and control elements. It is constructed as a torsion box
beam with a foamed core to provide strength, stiffness and
light weight.
42
-------
Testing. The completed device was supported from an A-Frame
gantry and tested in an 18 ft. diameter tank with a 4 ft.
depth. Approximately 3-1/2 ft. of water were placed in the
tank. The design of the device was aimed at a shallow draft
situation. Approximately 30 gals of oil were placed on the
surface of the tank and recovered in tests on the system.
Such an oil slick is less than the thickness of oil re-
coverable by straight vacuum techniques. Figure 17 illus-
trates the' test area set up and floor plan. Figure 18 is
a photograph of the test area. The rapidity of collection
observed in- these tests proved that such thin slicks can
be treated by the air modulated vacuum recovery method.
The results of several tests are presented in Table 14.
The results of the tests show recovery rates of 450 gal/hr
of oil. Under optimum operating conditions the water con-
tent of the recovered oil was observed qualitatively to be
<10 volume percent. (Figures 19 and 20 present alternate
photographs of the oil recovery operation,)
TABLE 14
Results of AMYOR Device Oil Recovery Tests
Test
Time to Time of Quantity Rate of
Initialize Test Vacuum Recovery Recovered Recovery
Minutes Minutes Gal Gal/Hr
I
2
3
4
5
6
7
10
10
8
5
6
6
8
15
10
12
7
5
8
4
38
35
37
30
32
33
31
152
210
165
229
384
248
465
The tests were conducted in the following manner. Approxi-
mately 25-30 gals of oil were placed on the surface of the
tank ( 254 sq. ft.). The oil quantity was sufficient to
spread to form a slick of ~4 mm thickness. The point of
this test was to observe the time and manner of recovery of
43
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Compressor
Air
Air
Distribution
Manifold
Control
Lines
Noise
Reducer
2" Pump Return
Vacuum
Receiver
Jest Tank
AIVOR Device
Glass Viewing Ports
1. Underbridge
2. Oil Recovery Line
FIGURE 17
Floor Plan-Test Area
44
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^M
»AW?f
? n
&*%.* *&&:.(' '«
lW««»v-^/"-^ Wi
•£^*^.^Xc-^7'-. ".-
FIGURE 18. Photograph of AMVOR Device in Test Tank
45
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FIGURE 19.
Photograph of Oil Recovery Operation with AMVOR
Device (View A)
FIGURE 20.
Photograph of Oil Recovery Operation with AMVOR
Device (View B)
46
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such a thin slick. The surfactant was added to oil to aid
foam generation. The system was in a flooded condition.
The compressor was started, controls set in manual mode
until the proper floating trim of the device was attained,
then switched to auto-level control mode. The vacuum was
applied and the oil foam collected. Observation of the
glass sections of the recovery lines permitted a visual
check on the system performance. The quantity of recovered
oil was measured by change in content of the receiver with
time and the rate of recovery could then be determined.
Approximately5 5 minutes were required to stabilize the
system in the running condition. After this time, the
vacuum was turned on and about 4 minutes on the average
were required to accumulate the oil in the receiver drum.
The water content was kept to a minimum through proper
control of the vacuum collection head. The recovery of
the 30 gals of oil proceeded at a rate of about 450 gals/hr,
The water content of the oil collected under present opti-
mum conditions was less than 10% and it is believed that
lower water contents can be routinely obtained with further
testing and optimization.
Greater quantities of oil could be placed on this test tank
surface but they would appear to bias the result toward
higher values for pumping transfer. The system is one
which can rapidly recover the oil from quiet water surfaces.
Further tests are warranted under field conditions for the
system. When the discharge from the water pumps is rapid
disturbances are generated on the water surface which is
about three inch waves with a wave length of about two feet.
Such disturbances are easily handled by the device. Modi-
fication or addition to the device to handle larger distur-
bances will be considered in the discussion.
47
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SECTION VI
DISCUSSION
Most recovery devices currently have severe limitations
with respect to (a) sustained oil recovery and (b) oil
recovery in disturbed water conditions.
The philosophy of design of the AMVOR device in the program
has been to attempt to increase the efficiency of operation
of one of the more effective methods - namely vacuum suction,
Vacuum suction has been considered by many to be the most
economical method of recovery when applicable, but before
AMVOR it suffered from the problem of being unable to handle
thin oil slicks.
The AMVOR technique generates an oil rich foam and at the
same time permits modulation of the vacuum suction to
eliminate the drawback of pulling too much water along with
the oil. The system designed and successfully tested in
this program overcomes this drawback and extends the range
of application of the vacuum recovery technique to very thin
oil slicks and further permits recovery of oil on cost
efficient basis to below transparency in the oil film.
The prototype apparatus assembled in this problem embodied
all the elements for remote field operation. The testing
of the device was successful in rapidly recovering thin oil
slicks from test tanks. The design of the device and its
engineering parameters projects a capability of recovering
oil under field conditions at the rate of 90 gal/min. The
water capable of being treated by the device can be esti-
mated at ~103,000 gal/hr over an 18' radius of influence as
shown in Table 15. The weight of the present device permits
it to be air transportable and rapidly deployed.
Preliminary indications from waves generated in the test
tank are that recovery can proceed under disturbed water
conditions. Wave action was generated by the water pump
exhaust from the device. The wave action in the 18'
diameter tank was approximately 3-4 inches peak to trough
and 1 to 2 feet peak to peak. Is the waves moved into the
sump carrying oil the trim of the system responded rapidly
due to increased pumping action. Oil was recovered under
these conditions with a greater water content (~3Q% by
volume).
The water content was routinely less than 10% under opera-
tion conditions. Time did not permit optimization to the
levels of <3% water content exhibited routinely in the
laboratory scale apparatus. The adaptability and parameter
variation (i.e., trim, sparger levels, sparging rate, etc.)
49
-------
Compressor
Air Distribution
Manifold
Chain
Hoist
fl
,J
Water
\
1
AMVOR Device
Deck Panel Removed for
Lowering Modified AMVOR
Device from Gantry
Sloping Bar Screen
oom
Slick
FIGURE 21
Plan of AMVOR Device in Field Operation with Catamaran Work Boat
50
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is expected to permit the operation to attain such low
water contents in recovered oil in further field testing.
TABLE 15
Summary of AMVOB Device Specifications
A. Demonstrated Performance in 18' Diameter Test Tank
Oil Slick Thickness (<4 mm) initial thickness
30 gal. oil
7500 Gal.Water
Recovery Rate 450 Gal. Oil/Per Hour
Final Oil Thickness - transparent oil sheen on surface
Area of Influence >9* Radius
Oil-Water Transfer Capacity 26,000 gph
B. Capability of AMVOR Device (Projected for Field
Operations)(Based on Engineering Limitations of Elements)
Oil Slick Thickness Initial No Large Limit and No
Lower Limit
Projected Recovery Rate -90 Gal./Min
Oil/Water Treatment Volume -102,500 Gal./Hr
7500 Gal H?0 x 60 min'hr"1=102,500 Gal./Hr
+ 30 Gal Oil 4 min recovery time
Area of Influence:
Conservative Estimate 18' Radius
Device and Accessory Elements Capable of Helicopter
Air Transport and Air Droppable
Figure 21 illustrates how the device may be used with the aid
of a catamaran work boat which has deck-panel removed. The
catamaran, thus equipped may serve to test the device under
field conditions. The equipment at hand would require only
51
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minor modification to include debris handling elements.
Such elements might include a bar screen which would also
serve to moderate the effects of small waves. The cata-
maran thus described would function with the aid of a
deployed oil containment boom.
The device is capable of remote operation with minor
attention from an operator.
Figure 22 is an aerial view of the Cuyahoga River and one
can see the many thin oil slicks present along its course.
These are further identified by circles on the photograph.
The lower Cuyahoga River and Navigation Channel are known
to be seriously degraded. "Throughout the Cleveland area
(it) is a virtual waste treatment lagoon choked at times
with debris, oils, scums, and organic floating sludges.
The river appears to be chocolate brown or rust colored
and most of the year has no visible life." (10) Fifteen
industrial concerns have been recognized as contributors
to oil and grease pollution in the Cuyahoga River (11).
The total quantity of oil influent to the Cuyahoga River
is unknown. Only three of the fifteen contributors have
been gauged and they alone add approximately a ton of oil
per day to the river (2), Thus, the Cuyahoga is typical
of many heavily traveled rivers in the heart of an industrial
complex and would serve well to provide a field test area
for the AMVOR device.
The estimated materials and equipment cost of the AMVOR
device is approximately $5,800 (not including rental or
purchase of an air compressor). The catamaran system
described above is estimated to cost $12,000.
52
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W
-*
-• -
'*• .!g^iV . "'^'xM?**' -•- '*?*^t>:r
'Js3S* t»
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i , t>- ' , *ass. ' - v,nt\- « - '%" "' "^-i-^^- ""
'\'^f"-'" X3 ""'**- '**v*i&
W><7
-------
Page Intentionally Blank
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SECTION VII
A CKNOWLEDGEMENTS
The support of the Mayor of the City of Cleveland, Ohio,
Honorable Carl B. Stokes, is acknowledged with sincere
thanks. The efforts and sponsorship of this program by
Mr, Benjamin S. Stefanski, II, former Director of Public
Utilities, City of Cleveland, are gratefully acknowledged.
Dr. Edward J. Martin, Director of the Cleveland Clean Water
Task Force was Project Director.
Special thanks are extended to Mr. Larry Politzer, Grant
Coordinator and Mr. David A. Carpenter, Industrial Co-
ordinator, both of the Clean Water Task Force for their
counsel and interest.
Mr. Ray Roth, Assistant Commissioner and Mr. James Schafer
of the Bureau of Waste Water Quality Control, City of
Cleveland provided valuable assistance and samples of waste
oil acquired from the Cuyahoga River for testing and
evaluation.
Mr. Richard W. Sicka, Group Leader, Horizons Incorporated
was program manager and directed the experimental and
construction phases of the program.
A number of members of Horizons Incorporated technical
staff provided valuable assistance throughout the program.
The effort and counsel of Dr. Selwyn H. Rose are gratefully
acknowledged. J. J. Bikerman served as a special consultant
in the surface chemistry aspects of the program.
Dr. J. S. Thornton and J. Jacobs aided in the engineering
design of the model device.
Special thanks are extended to D. Wheeler for his assistance
in all phases of the program.
The support of the project by the Environmental Protection
Agency and the help and interest provided by Mr. Harold Bernard,
Mr. Ralph Rhodes and Mr. Clifford Risely, Jr., the Grant
Project Officer are acknowledged with sincere thanks.
55
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Page Intentionally Blank
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SECTION VIII
REFERENCES
1. "Combating Pollution Created by Oil Spills", A. D.
Little, Inc., Cambridge, Mass., June 1969, for U. S.
Coast Guard, Dept. of Transportation, Vol. 1 Methods.
AD 696 635.
2. "Study of Equipment and Methods for Removing Oil from
Harbor Waters", August 1969, Battelle Memorial Insti-
tute, Richland, Washington. AD 696 980.
3. "Oil Spillage Study:Literature Search and Critical
Evaluation for Selection of Promising Techniques",
Battelle Memorial Institute, Richland, Washington.
AD 666 289.
4. "Systems Study of Oil Spill Cleanup Procedures Volume
I:Analysis of Oil Spills and Control Materials",
February 1970, Dillingham Corporation, La Jolla, Calif.
5. A. L. Scott and S. E. Gifford, "Removal of Oil from
Harbor Waters", Technical Note N-964, Naval Civil
Engineering Lab., Port Hueneme, Calif., February 1968.
6. G. Beduhn, "Removal of Oil and Debris from Harbor
Waters", Technical Note 825, Naval Civil Engineering
Lab., Port Hueneme, Calif., 1966.
7. N. A. D'Arcy, "Dissolved Air Flotation Separates Oil
from Waste Water", Oil and Gas J. 5_0, No. 27, 319-22
1951.
8. A. H. Beebe, "Soluble Oil Wastes by Pressure Flotation",
Sewage and Industrial Wastes, 125, No. 11, 1314-23,
November 1953.
9. T. Boyd, et. al., "Flotation of Hydrocarbon Impurities
in Water", U. S. 2,759,607, August 21, 1956.
10. Lake Erie Report, A Plan for Water Pollution Control,
U. S. Dept. of the Interior, Federal Water Pollution
Control Administration, Great Lakes Region, August
1968, p. 45.
11. ibid, page 101.
57
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Page Intentionally Blank
-------
SELECTED WATER
RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
Re i
w
, t U
AIR MODULATED VACUUM OIL RECOVERY COLLECTION
OF SPILLED OIL (FOAMS),
Sicka, R. W.
City of Cleveland
15080 EHP
Typo . ' Rep&i - jnd
Periou Cover eti
Environmental Protection Agency report
number 1PA-B2-72-033, August 19J2.
A method of oil harvesting was developed involving the air modulated vacuum
oil recovery technique. The collection of thin oil slicks from water surfaces by
the method of oil foam generation and air modulation of vacuum oil recovery was
developed in an experimental and engineering design project. This resulted through
construction of a prototype device which has proved capable of rapidly recovering
thin slicks of oil from water surfaces. Very little water is present in the re-
covered oil (<10% by volume).
The range of application of vacuum oil recovery has been successfully extended
to thin oil slicks (<4 mm) through the application of controlled air modulation and
oil foam generation. The prototype device was designed for remote operation and
hence possesses self contained power sources.
The two foot diameter prototype demonstrated performance by treating 7500
gallons of oil and water in a test tank in 4 minutes and recovering the oil at a
rate of 450 gal/hr from this very thin oil slick. Thicker slicks could be re-
covered much more rapidly.
The capabilities of treating much greater quantities of oil/water by this
prototype device are dicsussed.
~)esctljitot&
*0il Pollution - Recovery, *Vacuum Oil Skimming, *Air Modulation Oil Removal,
*0il Foams
*Foams, Oil Skimming
•'". '" -eity w,
r ,tc-> !
.' ' C)
•1. ' . of
' *>' ^
Send To:
WATER RESOURCES SCIENTIFIC INFORMATION CENTER
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON, D. C. 2O24O
Richard W. Sicka
Horizons Incorporated
ft CT. S. GOVERNMENT PRINTING OFFICE ; 1972-514-146,
-------
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