United States       Industrial Environmental Research  EPA-600/2-79-114
Environmental Protection  Laboratory            June 1979
Agency          Research Triangle Park NC 27711
Research and Development
Particulate  Sampling
and Support:
Final Report

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                  RESEARCH REPORTING SERIES


Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional  grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:

    1.  Environmental Health Effects Research

    2.  Environmental Protection Technology

    3.  Ecological Research

    4.  Environmental Monitoring

    5.  Socioeconomic Environmental Studies

    6.  Scientific and Technical Assessment Reports  (STAR)

    7.  Interagency Energy-Environment Research and Development

    8.  "Special"  Reports

    9.  Miscellaneous Reports

This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series.  This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental 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.
                        EPA REVIEW NOTICE
This report has been reviewed by the U.S. Environmental Protection Agency, and
approved for publication. Approval does not signify that the contents necessarily
reflect the views and policy of the Agency, nor does mention of trade names or
commercial products constitute endorsement or recommendation for use.

This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

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                                           EPA-600/2-79-114
                                           June 1979
Particulate Sampling and Support:
                  Final Report
                           by

              Kenneth M. Gushing and Wallace B. Smith

                   Southern Research Institute
                   2000 Ninth Avenue, South
                  Birmingham, Alabama 35205
                   Contract No. 68-02-2131
                   Program Element No. INE623
                EPA Project Officer: D. Bruce Harris

             Industrial Environmental Research Laboratory
               Office of Energy, Minerals, and Industry
                Research Triangle Park, NC 27711
                        Prepared for

             U.S. ENVIRONMENTAL PROTECTION AGENCY
                Office of Research and Development
                    Washington, DC 20460

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                            ABSTRACT

     This report summarizes the results from the research,
development and support tasks performed during the three year
period of this contract (11/75 - 11/78).   These tasks encom-
passed many aspects of particulate sampling and measurement in
industrial gaseous process and effluent streams.  Under this
contract Southern Research Institute calibrated and evaluated
cascade impactors, designed and evaluated novel particle sampl-
ing cyclones, wrote technical and procedures manuals for control
device evaluation and particle sampling methods, designed an
electrostatic precipitator backup for high flowrate systems, and
evaluated advanced concepts in monitoring particle mass and size
by optical systems.  A number of smaller tasks involving lower
levels of effort are also discussed.

     The appendix contains a list of technical documents pub-
lished under this contract.
                               11

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                              CONTENTS

Abstract	ii
Figures  	   v
Tables   	ix
Acknowledgment 	   x

   1.  Introduction	   1
   2.  Technical Summary 	   3
          Develop a computer based cascade impactor data
            reduction program  	   3
          Pocket programmable calculators to facilitate
            source sampling calculations 	   6
          Non-ideal cascade impactor behavior	   9
          Sampling charged monodisperse and polydisperse
            aerosols with cascade impactors	26
          Evaluation of cascade impactor substrate media .  .  29
          Development of five-stage series cyclone system.  .  35
          Electrostatic precipitator back up for
            sampling systems 	  41
          Guidelines for particulate sampling in
            industrial process streams 	  46
          Technical manual for particulate sampling equip-
            ment and methods	48
          Evaluation of the PILLS IV	51
          Cyclone and precollector for Fugitive Ambient
            Sampling Train (FAST)	52
          Design, construct and evaluate optimized
            cascade impactor 	  60
          Design a high temperature test facility	66
          A massive volume sampler for health effects
            studies	71
          Calibration of source test cascade impactors ...  75
          Calibration of Soviet particle sizing
            instruments	88
          Calibration of the Source Assessment Sampling
            System cyclones (SASS)  	  96
          Procedures Manual for Electrostatic Precipitation
            Evaluation	114
          Review of documents and reports furnished by EPA  . 116
          USA-USSR scientific information exchange program  . 117
          EPA/IERL/PMB exhibit booth at the 1977
            APCA annual meeting	118
          Calibration of a SASS middle cyclone for the
            health effects research laboratory/RTP 	 121
          Procedures manual for fabric filter
            evaluation	126

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          Advances in particle sampling and measurement
            symposium	128
          Presentation to Federal Republic of Germany. .  .  .  130
          Particulate sizing instrument evaluation 	  131

References	132
Appendix	  134

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                             FIGURES

Number                                                      Page

  1    HP-65 and HP-25 programmable calculator source
         measurement booklets	    8

  2    Composite of calibration data for the Andersen
         impactor stages 2 through 7 	   12

  3    An illustration of the four modeled stage collection
         efficiency curves of a typical stage of the
         Andersen impactor.  Model 1 is the ideal behavior
         model, Model 2 is the normal bounce model, Model
         3 is the no bounce model, and Model 4 is the
         extreme bounce model	   14

  4    Recovered size distributions on a cumulative per-
         centage basis from the Brink impactor models for
         ag = 2.0 and MMD's of 1.5, 4.5, 13.5, and 27 ym. .   15

  5    Recovered size distributions on a cumulative per-
         centage basis from the Brink impactor models as
         shown in Figure 4 with the backup filter catches
         omitted from the analysis	   16

  6    Recovered size distributions on a cumulative per-
         centage basis from the Brink impactor models for
         ag = 3.0 and MMD's of 1.5, 4.5, 13.5, and 27 ym..   17

  7    Recovered size distributions on a cumulative per-
         centage basis for the Andersen impactor for ag =
         2.0 and MMD's of 1.5, 4.5, and 13.5 ym.  The back-
         up filter was excluded from analysis in the results
         shown	   18

  8    Recovered size distributions on a differential basis
         from the Brink impactor models for MMD's of 4.5
         and 27 ym and ag's of 2 and 3.	   20

  9    Recovered size distributions on a differential basis
         from the Andersen impactor models for MMD's of
         1.5 and 13.5 ym and ag's of 2 and 3	   21

 10    Flow chart for acid wash treatment of glass fiber
         filter material 	   34

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 11    EPA-SoRI  five  stage cyclone  	     36

 12    Collection  efficiency of  the EPA-SoRI cyclones at a
        flowrate  of  28.3 £/min, a temperature of  25°C,
        and  for a particle density of  1.00 gm/cm3  ....     39

 13    Collection  efficiency of  the EPA-SoRI cyclones at a
        flowrate  of  14.2 £/min, a temperature of  25°C,
        and  for a particle density of  1.00 gm/cm3  ....     40

 14    Schematic of the electrostatic collector with the
        disc discharge electrode installed	     42

 15    ESP  collector  assembly drawing	     44

 16    Electrostatic  precipitator backup filter	     45

 17    Schematic diagram of Fugitive Ambient Sampling
        Train	     53

 18    Berglund-Liu type vibrating orifice aerosol
        generator system	     54

 19    Ammonium  fluorescein aerosol particles generated
        using the vibrating orifice aerosol generator  .  .     56

 20    Collection  efficiency versus particle diameter for
        the  FAST  pre-separator  impactor and cyclone  ...     59

 21    Assembly  drawing of 0.5 ACFM optimized cascade
        impactor	     65

 22    Preliminary layout for high temperature, low pres-
        sure wind tunnel test facility	     67

 23    Schematic diagram of massive volume  sampler  for
        Health  Effects Studies	     72
                                             i
 24   Theoretical impactor efficiency  curves for rectangular
       and  round impactors showing the effect of  jet-to-
       plate distance S, Reynolds number Re,  and  throat
       length T.	      77

 25   Collection efficiency vs. Sty.  Andersen Mark III
       stack sampler with glass fiber collection  sub-
       strates 	     79

 26   Collection efficiency vs. Sty.  Brink Model BMS-11
       cascade impactor with glass fiber collection sub-
       strates 	     QQ

27   Collection efficiency vs. Sty.  Brink Model BMS-11
       cascade impactor with greased collection plates .     81
                             VI

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28  Collection efficiency vs. /$.  MRI Model 1502 in-
      ertial cascade impactor with greased collection
      plates
29  Collection efficiency vs. /if.  Sierra Model 226 source
      cascade impactor with glass fiber collection sub-
      strates. Sampling flow rate is 14 LPM .......      83

30  Collection efficiency vs. /^.  Sierra Model 226 source
      cascade impactor with glass fiber collection sub-
      strates.  Sampling flow rate is 7 LPM .......      84

31  Collection efficiency vs. ifty .  University of Washing-
      ton Mark III source test cascade impactor with
      greased collection plates .............      85

32  Cascade impactor wall loss vs. particle diameter . .      86

33  Soviet 14-stage cascade impactor ..........      89

34  Soviet 3-stage impac tor/cyclone ...........      89

35  Collection efficiency vs. particle diameter.
      Soviet 12-stage impactor/cyclone.  ,.,.,.„..      90

36  Collection efficiency vs. particle diameter.
      Soviet 12-stage cascade impactor .........      91

37  Collection efficiency vs. particle diameter.
      Soviet 3-stage cascade impactor ..........      92

38  Collection efficiency vs. particle diameter.
      Soviet 14-stage cascade impactor (small cutpoints) .     94

39  Collection efficiency vs. particle diameter.  Soviet
      14-stage cascade impactor (large cutpoints) ....      95

40  Schematic of the Source Assessment Sampling System .      97

4*1  Collection efficiency vs. particle diameter.
      Large SASS cyclone ................      98

42  Collection efficiency vs. particle diameter.
      Middle SASS cyclone ................      99

43  Collection efficiency vs. particle diameter.
      Small SASS cyclone ................    100

44  SASS cyclone cutpoints ...............    101

45  Collection efficiency vs. particle diameter.
      Large SASS cyclone ................    103


                            vii

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46  Collection efficiency vs. particle diameter.
      Unmodified middle SASS cyclone 	     104

47  Collection efficiency vs. particle diameter.
      Modified middle SASS cyclone 	     105

48  Collection efficiency - temperature relationship
      SASS middle cyclone	     109

49  D50 - viscosity relationship SASS middle cyclone .  .     HO

50  Collection efficiency - particle density relationship
      SASS middle cyclone	

51  Collection efficiency at 400°F,  4 SCFM SASS middle
      cyclone	     113

52  Exxon SASS cyclones	     123
                          Vlll

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                            TABLES
Number
1
2
3
4
5

Program flow for the cascade impactor data
Simulation conditions of the modeled impactor
Percent errors in AM/AlogD, Andersen impactor. . . .
Percentage of trial cases in which recovered value
Page
4
11
23
24

       of (AM/AlogD) is within the indicated factor of
       the true value	    25

 6   Laboratory calibration of the five-stage cyclones. .    38

 7   FAST impactor and cyclone calibration data 	    58

 8   Criteria for impactor design 	    61

 9   Optimized impactor design specifications 	    62

10   Optimized impactor design specifications 	    63

11   Optimized impactor design specifications 	    64

12   SASS middle cyclone calibration data	   108
                               IX

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                         ACKNOWLEDGMENT

     The encouragement and support of our Project Officer,
D. Bruce Harris, during the entire contract period is grate-
fully acknowledged.

     Over the three year period of this contract, many
individuals in the Southern Research Institute's Physics Divi-
sion contributed to the success of this program.  Although
their names are too numerous to mention, their dedication and
efforts are acknowledged.
                              x

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                            SECTION  1

                          INTRODUCTION
     The scope of the research, development, and support per-
formed for the Environmental Protection Agency under Contract
68-02-2131 (November 20, 1975-November 19, 1978) by Southern
Research Institute covered many aspects of particulate sampling
in gaseous process and effluent streams.  Specific objectives
which were identified and given priority during this contract
were to:

     1.  Identify current and future requirements for particu-
late sampling - the nature of the particles  (shape, volatility,
concentration, size distribution, charge, etc.), the sampling
conditions (temperature, pressure, entrained fluids, etc.),
and the goals of the sampling programs  (control device evalua-
tion, health effects, etc.).

     2.  Continue research on the non-ideal or unmodelled be-
havior of cascade impactors.  Investigate problems in using
impactors on nonroutine process streams  (wet, high temperature,
high pressure).  Design cascade impactors which incorporate
all that we have learned about their fundamental behavior and
operational problems.

     3.  Design, fabricate, and test cyclone systems for par-
ticle sizing.  Evaluate existing cyclone systems for particle
sizing effectiveness.  Consider alternatives to back up filters
in high flow rate applications.

     4.  Study alternatives to impactors and cyclones for par-
ticle sizing such as optical, electrical, or hybrid systems.
Concentrate on devices which offer the possibility of real
time, automatic, sampling  and analysis.

     5.  Study methods of Quality Assurance  in  sampling and
calibration programs.

     6.  Generate and review documents on particulate sampling
and continually update our bibliography and  literature survey.

     7.  Continue to study and evaluate new  techniques, ideas,
and instruments for particulate sampling.

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     8.  Attend and organize meetings and symposia on particu-
late sampling.

     9.  Provide consulting and research and development support
to EPA programs.

     There are two sections in the remainder of this report.
The Technical Summary contains a description of the results
from each task undertaken during the contract period.  The
Appendix presents a complete list of technical documents printed
or to be printed under this contract.

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                             SECTION 2

                         TECHNICAL SUMMARY


DEVELOP A COMPUTER BASED CASCADE IMPACTOR DATA REDUCTION PROGRAM

     Cascade impactors have gained wide acceptance as a practi-
cal means of making particle size distribution measurements.
These devices are regularly used in a wide variety of environ-
ments, ranging from ambient conditions to flue gas streams
of 500°C  (950°F).  Specially fabricated impactors can be used
for more extreme conditions.

     Because of the usefulness of cascade impactors, research has
been funded to explore the theoretical and practical aspects of
impactor operation.  As part of this research, an effort has been
made to design a comprehensive data reduction system which will
made full use of cascade impactor measurements.

     The cascade impactor data reduction system  (CIDRS) is
designed to automatically reduce data taken with any one of
four commercially available round jet cascade impactors:  the
Andersen Mark III Stack Sampler, the Brink Model BMS-11 (as
supplied and with extra stages), the University of Washington
Mark III Source Test Cascade Impactor, and the Meteorology
Research Incorporated Model 1502 Inertial Cascade Impactor.
Provision is not made in this system for reducing data taken
with slotted jet impactors.

     The computer programs which comprise this data reduction
system are written in the FORTRAN IV language.  The plotting sub-
routines used were written specifically for the Digital Equipment
Corporation (DEC) PDP-15/76 computer, and these programs are
not compatible with other plotting systems.  However, these
programs can be used as a guide when revision is made for use
with another operating system.  The overall system incorporates
six programs:   MPPROG, SPLINl, GRAPH, STATIS, PENTRA, and PENLOG.
These six programs are described briefly in Table 1.  Impactor
design, particulate catch information and sampling conditions from
single impactor runs are used to calculate particle size distribu-
tions.  MPPROG and SPLINl perform data analyses and make curve
fits, while GRAPH is totally devoted to various forms of graphical
presentation of the calculated distributions.  The particle size
distributions can be output in several forms.  STATIS averages
data from multiple impactor runs under a common condition and
PENTRA or PENLOG calculates the control device penetration and/or
efficiency.

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                            TABLE I
            PROGRAM FLOW FOR THE CASCADE IMPACTOR
                     DATA REDUCTION SYSTEM


                 BLOCK  1.   SINGLE  RUN  ANALYSIS
                  I.   Impactor  Program  (MPPROG)

Takes testing conditions and stage weights to produce stage
Dso's, cumulative and cumulative % mass concentrations 
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     The system utilizes impactor specific calibration  infor-
mation together with operating conditions and other pertinent
information such as stage weights, sampling duration, etc.,
to determine particle size distributions in several forms  for
individual runs.  A spline technique  is applied to fit  a curve
to the cumulative size distribution obtained from each  individual
impactor run.  These fitted curves have forced continuity  in
coordinates and slopes.  Averages of  size distributions for
multiple runs are made using the fitted curves to provide  inter-
polation values at a consistent set of particle diameters,
irrespective of the diameters at which the data points  fall
in the original individual run data sets.  Statistical  analy-
ses are performed to locate and remove outliers from the data
being averaged, following which averages, variances, standard
deviations and confidence intervals are calculated.  The averages
and statistical information are available in tabular and graph-
ical form in several size distribution formats  (cumulative
mass loading, cumulative percentage by mass, differential mass, and
differential number).  The averaged data are stored in  disk
files for subsequent manipulation.  Additional programs permit
data sets from control device inlet and outlet measurements
to be combined to determine fractional collection efficiencies
and confidence limits of the calculated efficiencies.

     These results are available in graphical form with a choice
of log-probability or log-log presentations.  As mentioned
above, the program is set up to handle all commercially avail-
able round jet cascade impactors, including common modifica-
tions, which are in current use in stack sampling.  Other
round jet impactors can be easily substituted and slot  type
impactors could be accommodated with  slight program revision.

     Two reports have been written which describe this  data
reduction system.  An executive summary of the program  includ-
ing several examples is given in "A Data Reduction System for
Cascade Impactors", EPA-600/7-78-132a, July 1978.  The detailed
program description with program listings can be found  in  "A
Computer-Based Cascade Impactor Data  Reduction System," EPA-
600/7-78-042, March 1978.

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POCKET PROGRAMMABLE CALCULATORS TO FACILITATE SOURCE SAMPLING
CALCULATIONS

     A library of twenty-two programs to facilitate calculations
associated with source sampling and air pollution measurement
studies  was  compiled for the Hewlett-Packard HP-65 and HP-
25 Pocket Programmable Calculators.  This library contains
EPA Reference Methods 1-8, cascade impactor programs, and sev-
eral others.   Each program includes a general description,
formulas used in the problem solution, a numerical example,
user instructions, and a program listing.

     A list of the calculator programs follows.

APol-01   Method 1 - Sample and Velocity Traverses for Stationary
            Sources

APol-02   Method 2 - Determination of Stack Gas Velocity and
            Volumetric Flow Rate (Type S Pitot Tube)

APol-03   Method 3 - Gas Analysis for Carbon Dioxide, Excess
            Air, and Dry Molecular Weight

APol-04   Method 4 - Determination of Moisture in Stack Gases

APol-05   Method 5 - Determination of Particulate Emissions from
            Stationary Sources

APol-06   Method 6 - Determination of Sulfur Dioxide Emissions
            from Stationary Sources

APol-07   Method 7 - Determination of Nitrogen Oxide Emissions
            from Stationary Sources

APol-08   Method 8 - Determination of Sulfuric Acid Mist and
            Sulfur Dioxide Emissions from Stationary Sources

APol-09   Cascade Impactor Operation

APol-10   Impactor F'low Rate Given Orifice AH

APol-11   Impactor Flow Rate, Given Gas Velocity and Nozzle
            Diameter

APol-12   Impactor Sampling Time to Collect 50 Milligrams

APol-13   Impactor Flow Rate, Sample Volume, Mass Loading

APol-14   Impactor Stage Dso

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APol-15   /¥  Calculation - Round Jets

APol-16   /¥  Calculation - Rectangular Slots

APol-17   Cumulative Concentration vs Dso and AM/AlogD vs
            Geometric Mean Diameter

APol-18   Mean, Standard Deviation, 90/95% Confidence Interval,
            Mean ± CI

APol-19   Resistivity and Electric Field Strength

APol-20   Channel Concentrations for the KLD Droplet Measuring
            Device  (1-600 urn) DC-1

APol-21   Aerotherm High Volume Stack Sampler; Stack Velocity,
            Nozzle Diameter,  Isokinetic AH

APol-22   Flame Photometric Detector Calibration by Permeation
            Tube Technique

     Both of  the program documents were published  in two formats.
The  first of  these was  the normal SVxll" bound version; the
second was  a  special, 5"x7" spiral bound version with plastic
laminated covers.  The  HP-65  document was published under the
title "HP-65  Programmable Pocket Calculator Applied to Air
Pollution Measurement Studies:  Stationary Sources," EPA-600/8-
76-002, October 1976  (NTIS-PB 264 284/1BE).  The HP-25 document
was  published under the title "HP-25 Programmable Pocket Calculator
Applied to Air Pollution Measurement Studies:  Stationary Sources,"
EPA-600/7-77-058, June  1977 (NTIS-PB 269 666/4BE).  A photograph
of the two spiral bound booklets is shown in Figure 1.

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00

                Figure 1.  HP-65 and HP-25 programmable calculator source measurement booklets,

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NOW-IDEAL CASCADE IMPACTOR BEHAVIOR

     Cascade impactors have become commonly  used  measurement
devices for the determination of size distributions  of  particu-
late matter emissions from industrial sources.  Data obtained
with impactors are used to characterize  emissions from  sources,
to determine the performance of particulate  control  devices,
and in the selection and design of control devices for  specific
sources.

     Data provided by impactors are of relatively low resolu-
tion and do not permit the exact reconstruction of the  size
distribution of the aerosol being sampled, even over the  limited
range of sizes normally covered by most  impactors (approxi-
mately 0.5 to 10 ym).  However, little has been done to esti-
mate the magnitude of the uncertainties, or  errors,  which are
inherent in the method insofar as they relate  to  industrial
source emission measurements and determinations of fractional
collection efficiencies of control devices.  The  study  described
here was one with the specific goals of  estimating the  effects
of two non-ideal operating characteristics of  impactors on
the data obtained with them.  These two  non-idealities  are
(1) the lack of step function stage collection characteristics
and (2) particle bounce.  Several authors1'2'3 have  proposed
various deconvolution procedures which,  when applied to impac-
tor data, would to a large degree, correct for the effect of
the finite slopes of the stage collection efficiency curves.
However, little use has been made of these procedures,  pri-
marily because noise in the data frequently  results  in  oscilla-
tory solutions with large negative values.   In any case,  little
quantitative information regarding the magnitude  of  the errors
introduced by the lack of sharp size cuts in impactors  commonly
used for stack sampling has been published.  The  magnitude
of errors introduced by particle bounce  has  not previously
been quantified although the existence of such errors has been
described in the literature.*'5'6'7

Technical Procedures

     The approach used in this study was the development  of
a computer model of cascade impactor performance.  The  model
was based on actual impactor performance as  measured in a cali-
bration study of commercially available  cascade impactors for
stack sampling.  A total of four simulation  models were used
for both a Brink impactor in a commonly  used modified configu-
ration for stack sampling and an Andersen Mark III stack  sam-
pler.  The use of glass fiber collection substrates  was assumed

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for both impactors.  Both grease and glass fiber substrates
are commonly used for sampling at temperatures below 150°C
(300°F) but no satisfactory greases have been found for use
at temperatures over 150°C.  Therefore, glass fiber substrates
must usually be used for collection substrates at elevated
temperatures.

     The first model for each impactor was one having  ideal
collection characteristics, i.e., step functions from  0%  to
100% collection at the stage D50's.  (The stage D5p is that
particle diameter at which the stage has a collection  effi-
ciency of 50%.  The D50 is generally used as the characteristic
cut off diameter for particles collected by the stage.)   This
model was used as a performance standard against which the
remaining three models could be compared and also provided
a basis for checking the program.

     The assumed operating conditions and resulting cut sizes
(Dso's) of the two impactors modelled in the study are given
in Table II.  The models of the Brink impactor included a cyclone
precollector which was assumed to have the same performance
characteristics in all three of the simulations other  than
that of the "Ideal Brink."  The cyclone performance was based
on calibration data for a cyclone in common use with the  Brink
impactor modified for stack sampling.  This cyclone has a col-
lection efficiency of 100% for particles larger than about
20 ym.

     The second model for each impactor used the actual cali-
bration data for each stage.  In this model the stage  collec-
tion efficiencies increased monotonically with increasing
Stokes numbers (increasing particle size) to a maximum value
of about 90% to 95%.  The efficiencies then decreased  for
larger Stokes numbers to a value of 35% to 40% and remained
constant thereafter.  A composite of the calibration data for
stages two (2) through seven (7) of the Andersen impactor,
which  illustrates the behavior described above, is shown  in
Figure 2.  Data for Stages 1 and 8 were offset from the tight
grouping of the data for the remaining stages and hence were
omitted in Figure 2 for purposes of clarity in illustrating
the behavior trends of the stage efficiency curves.  The  data
for the Brink impactor exhibited similar trends.  This model,
Model 2, is called the "Normal Bounce" model.

     The third model was identical to the second except that
the rollover and decline in efficiency for larger Stokes  numbers
was ignored.  Instead, the efficiencies were assumed to smoothly
increase to 100% and remain at that value for increasingly
larger Stokes numbers.  This is called the "No Bounce" model.
The fourth model was also identical to Model 2 with the excep-
tion that the collection efficiencies were assumed to  drop


                              10

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         Table II.
Simulation Conditions of the Modeled
  Impactor Performance
                               Brink
                                Andersen
Temperature, °C  (°P)
Gas composition
Particle density, gm/cm3
Flowrate, alpm  (acfm)
Barometric Pressure,
  mm Hg
       177 (350)
       Std. air
         2.27
         1.13  (0.040)

       749
                   177 (350)
                   Std. air
                     2.27
                    17.0 (0.600)

                   749
  Stage/Ds o
        1
        2
        3
        4
        5
        6
        7
        8
  601
  182
  39
  85
1.23
0.905
0.589
0.1982
         9
         6
         3
         1
7.84
7.40
4.44
2.87
1.58
0.855
0.449
0.200
1.  Stage 1 is a cyclone precollector.

2.  Stages 2 and 8 are part of the modifications  to the  impactor
                                 11

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   98
   90



s?

>  70
u

HI
u  50
E
u.
ui  30

O

U
3  10


8
UJ
O   2
co
 0.5


 0.1



0.01
                                           I
     0.04       0.1                         1.0

               SQUARE ROOT OF STOKES NUMBER (DIMENSIONLESS)
                                                                   10.0
                                                                  3630-027
  Figure 2.   Composite of calibration data for  the Andersen  impactor stages
              2 through 7.
                                   12

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rapidly to a value of 2% for Stokes numbers larger  than  that
at which the collection efficiency reached a peak in the cali-
bration data.  This model was termed the "Extreme Bounce" model.

     The use of the same basic collection efficiency curves
for the "No Bounce," "Normal Bounce," and "Extreme  Bounce"
models for particle sizes smaller than those for which the
collection efficiencies were maximal in the calibration data
is probably a realistic representation of the actual perfor-
mance of the impactors in collecting various types  of particles.
Rao5 found that impactor collection characteristics for dry
solid particles and oil particles were virtually identical
when glass fiber substrates were used for Stokes numbers smaller
than those at which the peak efficiency was reached for the
dry solid particles.  Beyond this point he found that oil par-
ticles were collected with efficiencies which increased to
100% with increasing Stokes number while the efficiencies
declined for the dry particles as a result of bounce.  Figure
3 shows an example of the four modelled collection  efficiency
characteristics of one stage of the Andersen impactor.

Results and Discussion

     The performance of each model of the two impactors was
evaluated for aerosols having log-normal size distributions
with mass median diameters (MMD) of 1.5, 2.6, 4.5,  7.8, 13.5,
and 27 micrometers and geometric standard deviations, a  , of
2, 3 and 4.                                            9

     Figures 4 through 7 show typical results for the two im-
pactors in a cumulative percentage presentation.  It is evident
from all four of these figures that particle bounce severely
distorts the size distributions, especially for aerosols hav-
ing large mass median diameters.  Figures 4 and 5 show the
results of the simulations for the same impactor and size dis-
tributions, the difference between the two being the omission
of the back-up filter catch in presenting the results in Figure
5.  Comparison of Figures 4 and 5 indicate that omitting the
back-up filter in calculating the cumulative percentages greatly
reduces the distortion resulting from bounce.  Comparison of
Figures 4 and 5 shows that increasing the width of  the input
size distribution  (increasing a ) reduces the distortion caused
by bounce although the distortion remains appreciable for the
extreme bounce models at large HMD's.

     Figure 7 shows the results from the Andersen models cor-
responding to three of the four cases for the Brink Model shown
in Figure 5.  Note that the deviations from the input distri-
bution resulting from bounce are more severe in the Andersen
results than in the Brink.  This difference in the  severity
                               13

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100 —
                           5          10         20

                           PARTICLE DIAMETER, jum
100
                                                                   3630-028
 Figure  3.  An  illustration  of  the  four modeled stage collection efficiency
            curves  of  a  typical stage  of  the Andersen impactor.   Model 1 is
            the ideal  behavior  model,  Model  2 is the normal bounce model,
            Model 3 is the no bounce model,  and Model 4 is the extreme
            bounce  model.
                                     14

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   99.8
N
CC
111
-I
V)
111
IU
U
EC
LU
Q.

Ill
U
NO BOUNCE

NORMAL BOUNCE

EXTREME BOUNCE
   0.01
                                         1.0
                               PARTICLE DIAMETER, jum
                                                         10.0
                                                                         3630-029
    Figure 4.   Recovered size distributions  on a cumulative percentage basis  from

                the Brink impactor models  for 0g = 2.0 and HMD's of 1.5, 4.5,  13.5,
                and 27 ym.  The bold lines represent the input distributions.
                                        15

-------
  99.8
til
N
cc
UJ
(/>

HI
    98
    90
    70
    50
    30
o
cc
UJ
a.
w   10
U
   0.5
   0.1
  0.01
     0.1
•  NO BOUNCE

A  NORMAL BOUNCE

•  EXTREME BOUNCE
                       1.0
                               PARTICLE DIAMETER,
10.0
                                                                         3630-030
   Figure 5.  Recovered  size  distributions on a cumulative  percentage basis from

              the Brink  impactor models as shown in Figure  4 with the backup

              filter catches  omitted from the analysis.  The bold lines represent

              the input  distributions.
                                     16

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  99.8
                     • NO BOUNCE
                     A NORMAL BOUNCE
                     • EXTREME BOUNCE
 0.01
        1.0

PARTICLE DIAMETER,
                                                                        10.0
                                                                      3630-031
Figure 6.  Recovered size distributions on a cumulative percentage basis from
           the Brink impactor models for Og = 3.0 and MMD's of 1.5, 4.5, 13.5,
           and 27 ym (backup filter included in the analysis).  The bold lines
           represent the input distributions.

                                      17

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  99.8
HI
N
 CO
 o
 K
 UJ
 OL
   98
    90
    70
    50|—
 <  30
    10
2
D
2
D  9
O  2
   0.5
   0.1
  0.01
                    • NO BOUNCE

                    A NORMAL BOUNCE

                    • EXTREME BOUNCE
     0.1
                              PARTICLE DIAMETER, jum
10.0
                                                                        3630-032
Figure 7.  Recovered size distributions  on a cumulative percentage basis for

           the Andersen impactor  for  ag  = 2.0 and MMD's of 1.5, 4.5, and 13.5 ym.

           The backup filter was  excluded from analysis in the results shown.

           The bold lines represent the  input distributions.
                                     18

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of the distortions apparently results  from  the  cyclone  pre-
collector on the Brink which removes most of  the  larger  parti-
cles that are responsible  for raising  the apparent  percentages
of fines in the recovered  size distributions.

     It should also be noted that  the  relative  errors in mass
median diameters become  increasingly large  as the MMD of the
input aerosol decreases.   The recovered HMD's were  found to
be systematically large  for test aerosol HMD's  below 10  urn.  The
recovered values of CTg were also systematically high with larger
relative errors at the lower values of a  ,  as would be  expec-
ted because of the low resolution  affordid  by impactors.

     In many cases  (e.g.,  control  device  fractional collection
efficiency studies) the  slope of the size distribution  curve,
expressed in mass concentration units, is the quantity  of
greatest interest.  The  most common manner  of presentation
of this slope is the  form  dM/dlogD (units of  mass concentra-
tion) .  The quantity  dM/dlogD is often approximated directly
from the impactor data,  stage by stage, as  Am./AlogD.,  where
                                                          f" H
    m. = mass concentration of particles  retained by the i
         stage


                         and AlogD. = log
                                          (D5o)i
The particle  diameter  is  then  taken  to  be  the  geometric mean
of  (Ds o) • and (Ds o) •  -, /
                        D   = /(D5o)i  x  (DsoJj^-L


     Figures  8  and  9  illustrate  recovered  size  distributions
presented  in  such a manner, together with  the  input  distribu-
tions,  for  representative  sets of  Brink  and  Andersen results.
The results for  the "extreme  bounce" case  are  not  shown  in
Figures 8  and 9  but the values in  those  cases  generally  fall
between the "no  bounce" and "normal  bounce"  cases  except for
the back-up filters,  for which the values  were  much  higher
in the  "extreme  bounce" case  than  in the other  two cases.
Except  for  the  finest size fractions,  represented  by the back-
up filter  catches,  and the fine  fraction tails  of  the low a
distributions,  the  agreement  between the recovered values
of (AM/ AlogD).  generally  lie reasonably close  to  the input
distributions.   However, errors  of up  to +35%  are  not infre-
quent.
                                19

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     .O
     m
      *
     Q

     O
     O
        10
       10
                       GEOMETRIC MEAN DIAMETER (MICROMETERS)
                                                                    3630-033
Figure 8.  Recovered size distributions on a differential basis from the Brink
           impactor models for MMD's of 4.5 and 27 ym and ag's of  2  and  3.
           The bold curves represent the input distributions.
                                   20

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            10°
         I



         s
         +rf
         !S
         S

         cf
         O
         O
10-1
           10-2
           10-3
           10-4
                     MMD = 13.5 jum

                     ag = 3
                                                     I      I
             10-1
                 10'°            101  10-1           10'°


                 GEOMETRIC MEAN DIAMETER (micrometers)
                                                                          3630-034
Figure  9.   Recovered s:Lze distributions on a differential basis from  the Andersen

            impactor models  for HMD's of 1.5 and  13.5 pm and erg's of 2 and 3.   The

            bold curves represent the input distributions.
                                         21

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     Tables III and IV show the errors, expressed as percentages,
in the recovered values of  (AM/AlogD)i for several cases  for
each of the two impactors.  (For the purpose of calculating
log D and D for the filter catches,  it was assumed that the
diameter range covered by the filter was  (DSo)e down to ^(DsoJa-

     Although no results for a  = 4  have been shown, the  agree-
ment between the recovered sizl distributions and the  input
distributions was progressively better as a  increased and
was quite good in all cases for a  = 4 withgthe exception of
back-up filter catches when bounce was present.

     Table V shows the percentages of cases in which the  re-
covered values (Am/AlogD). lay within factors of 1.2,  1.5,
and 2 of the true value.  From these results it appears that
the concentrations of fine particles as measured with  impactors
can seldom be taken to be known better than to within  a factor
much smaller than 1.5 unless the particles are known to be
adhesive or an effective adhesive coating can be applied  to
the substrates.

     There is some evidence,8'9 although it is not conclusive,
that the use of adhesive coatings  (greases) on the substrates
may become ineffective as the particulate deposits build  up
under the impactor jets.  This would result in the same type
of errors due to particle bounce resulting in back-up  filter
contamination by oversize particles  with greased substrates
as has been shown to occur with glass fiber substrates.

Conclusions and Recommendations

     From the evidence presented here, it is suggested that
back-up filter catches generally should be omitted from data
presentation when dry, non-sticky particulates are sampled.
Exceptions should be made only if the HMD is smaller than
about 2.5 ym.  In addition it is suggested that cyclone pre-
collectors having D5u's somewhat larger than the first impac-
tion stage D50 be used whenever a non-sticky particulate  is
sampled.  The use of such cyclones tends to greatly reduce
errors due to particle bounce.

     The results of this study were  reported at the 1977  Air
Pollution Control Association Annual Meeting in Toronto,
Ontario, as Paper No.  77-35.3, entitled "Non-Ideal Behavior
in Cascade Impactors."
                              22

-------
    Table III.  Percent Errors in AM/AlogD, Andersen Impactor
                     No Bounce
MMD:           1.5      4.5     13.5         1.5    4.5    13.5

Stage/Error
     F         144                            22     38
     8           9                           -14     -5
     7          -8       56                  -11     -4
     6         -18       13                  -10     -8       4
     5         -14      -19       18         -12    -17     -24
     4           6      -26      -20          -7    -21     -25
     3                  -19      -30          10    -15       0
     2                  -23      -28           9    -22     -24
                   Normal Bounce

     F         568    121000                  44    173    1720
     8          22       920                 -12      8     103
     7          -6       111                 -11      1      37
     6         -20         9     293         -12    -11       4
     5         -16       -18      39         -12    -16     -11
     4           5       -27     -17          -7    -21     -24
     3                   -20     -30           9    -16     -25
NOTE:  Values are omitted for stages for which the collected
       mass would be too small to be detected in field sampling
       programs.
                                23

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     Table IV.  Percent Errors in AM/AlogD, Brink Impactor
                     No Bounce
MMD:

Stage/Error
     F
     6
     5
     4
     3
     2
     1
     F
     6
     5
     4
     3
     2
     1
1.5   4.5
220
 -6
-43
-19
-15
 -1
 88
13.5
27
550
-10
-40
-20
-16
 -1
 86
220
-35
3
-3
-10
-14

238
-8
10
-4
-28
-15



84
-8
-15
Bounce



107
7
-18
        33
         7
1.5
24
-37
-32
-9
-4
4
34
4.5
53
-21
-39
-12
-9
-20
-3
13.5

13
-40
-5
-3
-23
-14
27


-37
4
8
-22
-14
       100
         3
41
-39
-29
-10
-4
4
33
123
-24
-33
-12
-10
-18
-4

12
-26
0
-3
-20
-16


-10
17
10
-16
-17
NOTE:  Values are omitted for stages for which the collected mass
       would be too small to be detected in field sampling pro-
       grams .
                                24

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      Table V.  Percentage of Trial Cases in which Recovered
                Value of (AM/AlogD) is Within the Indicated
                Factor of the True Value
                   Andersen
                                         Brink
Factor:

Stage/Percent
 of cases
     F
     8
     7
     6
     5
     4
     3
     2
1.2   1.5
2.0
0
57
65
65
75
30
40
(30)
31
71
76
80
100
100
90
(90)
38
79
82
90
100
100
90
(90)
Factor:

Stage/Percent
 of cases
     F
     6
     5
     4
     3
     2
     1
1.2   1.5
                                      0
                                     35
                                     11
                                     80
                                     74
                                     42
                                     71
                               33
                               59
                               47
                               95
                               91
                               96
                               72
2.0
             56
             82
            100
            100
             91
            100
            100
Andersen table covers all cases
 with
MMD = 1.5, 2.6, 4.5, 7.8, 13.5 and
 °g = 2, 3
for both normal bounce and no
 bounce
                    Brink table covers all cases with
                     with
                    MMD = 1.5, 2.6, 4.5, 7.8, 13.5,
                          27, and
                     ag = 2, 3
                    for both normal bounce and no
                     bounce
                                 25

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SAMPLING CHARGED MONODISPERSE AND POLYDISPERSE AEROSOLS WITH
CASCADE IMPACTORS

      In performing particle size distribution measurements
at control devices operating on industrial process  streams,
investigators are usually aware that  in some cases  charged
particles will be present in the gas  stream.  In order to
assess the influence of particle charge, three different ex-
periments were performed to determine whether or not  cascade
impactors sampling charged aerosols can yield erroneous par-
ticle size distribution measurements.  The commercially avail-
able  cascade impactors utilized in this study were  the Ander-
sen Mark III Stack Sampler, the Brink Model BMS-11  Cascade  Im-
pactor, the Meteorology Research, Inc. Model 1502 Cascade Impac-
tor,  and the University of Washington Mark III Source Test  Cascade
Impactor.  In general, the measured distributions indicated more
large particles and fewer small particles than actually existed.
The deviations from the true size distribution were found to be
a  function of the magnitude of charge.  The deviations were
smaller if glass fiber substrates were used as impactor collec-
tion  surfaces instead of the metal collection plates  alone.  For
charge levels representative of electrostatic precipitators oper-
ating at normal charging conditions  (an electric field strength
of 400,000 V/m and a current density of 3 x 10=l* A/m2), the dif-
ferences between the true and measured polydisperse size distribu-
tions sampled with glass fiber substrates were small.

      The three experiments are briefly described below.  In the
first experiment monodisperse aerosols were sampled by the
University of Washington Mark III, Andersen Mark III, and MRI
Model 1502 cascade impactors.  The second test involved the sampl-
ing of polydisperse aerosols with a Brink cascade impactor.  The
third experiment involved the sampling of polydisperse aerosols
with  the Andersen Mark III cascade impactors.  A review of  the
important parameters and conclusions for each experiment are
described below.

1st Test - Monodisperse Aerosol

      1.   Tests were done with the impactors operated  at the
recommended flow rate and with particle charges equivalent
to those expected at precipitator outlets.  However,  only two
particle sizes were used.

      2.   Wall losses were measured along with the stage collec-
tion  efficiency.

      3.   For charge levels approximately five times higher
than  those expected at a precipitator outlet, very  large effects
were  noted.
                              26

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     4.  For samples taken using glass-fiber substrates at
representative particle charge levels, the effect of particle
charge on impactor performance was found to be minimal.

     5.  Grounding the impactors generally increased stage
collection efficiencies.

     6.  The data from this experiment were not taken with
particle concentrations high enough to be representative of
those to be found at the outlet of industrial precipitators.

2nd Test - Polydisperse Aerosol Sampled with a Brink Impactor

     1.  Tests were done with the impactors operated at the
recommended flow rate with a polydisperse aerosol and particle
charges equivalent to those expected at precipitator outlets.
Only two stages of a Brink impactor were used.

     2.  The particle concentration was less than would be
expected at a precipitator outlet.

     3.  A test on wall losses showed that they play a sig-
nificant part in impactor performance when a charged aerosol
is sampled.

     4.  Tests using glass-fiber substrates did not show an
appreciable difference in the collection of charged and un-
charged particles.  Tests using bare metal substrates, however,
showed quite a difference between the collection of charged
particles and the collection of uncharged particles.
                                                              •
3rd Test - Polydisperse Aerosol Sampled with Andersen Impactors

     1.  Tests were performed with entire Andersen impactors
operated at the recommended flow rate and with glass-fiber
substrates only.

     2.  The particle concentration was similar to that ex-
pected at the outlet of an industrial electrostatic precipi-
tator.  The aerosol contained polydisperse ammonium fluores-
cein particles.

     3.  Wall losses were not considered separately, however,
no visible wall loss was observed for tests with particles
having moderate charge.  The wall losses were visibly evident
in the high charge tests.

     4.  Moderate particle charge levels had little effect
on impactor performance for the middle and lower stages.  For
stages with D5o's above 3 micrometers, up to about twice as
much mass was caught in the charged particle impactor than
in the neutral one.


                              27

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     5.  For charging conditions higher than those considered
moderate here, the effects of particle charge were more sig-
nificant both for the lower impactor stages and the upper impac-
tor stages, with the middle stages giving approximately true
mass measurements.

     The details of the experimental work performed under these
tasks is presented in a report entitled "Sampling Charged Particles
with Cascade Impactors," EPA-600/7-79-027, January 1979.
                               28

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EVALUATION OF CASCADE IMPACTOR SUBSTRATE MEDIA

     Cascade impactors are widely used  to determine particle
size distributions  in air pollution control device research
programs.  In these research programs a large variety of  flue
streams are encountered with temperatures ranging from ambient
to around 370°C  (700°F).  Gas analyses  show that many of  these
sources contain  some SO  components, particularly those asso-
ciated with fossil  fuel fired boilers.

     Most impactors have collection stages which are too  heavy
to allow accurate measurements of the mass of the particles
collected in each size fraction.  Weighing accuracy can be
improved by covering the stage with a lightweight collection
substrate made of aluminum foil, teflon, glass fiber filter
material, or other  suitable lightweight material , depending
upon the particular application.  Some  manufacturers now  fur-
nish lightweight inserts to be placed over the collection stages.
With such arrangements it is possible to collect enough material
on each stage to make an accurate determination of the mass
collected and avoid overloading  the stage.  If the stage  is
overloaded, some deposited particulate  matter can be reentrain-
ed and deposited on another stage or the back-up filter and
lead to erroneous results.

     Substrate materials may also serve the purpose of changing
the surface characteristics from those  of a bare metal or plastic
to something better suited to holding particles which impact.
Thus, various greases are often  used, either on bare impactor
plates, or, more frequently, on  metal foil substrates.

     Presented in the published  final report  (see page 32) are
the results of investigations concerning the use of two classes
of impactor substrates—greased  metal foils, and glass fiber filter
materials.  Tests were made under both  laboratory and field condi-
tions to evaluate each of several greases and filter materials.
The general purpose of this study was to identify specific
materials and handling techniques which may be used to improve
the accuracy of  weight measurements in  impactors by reducing
uncertainties arising from changes in substrate weights.

     Although normal glass fiber substrate preparation includes bak-
ing and desiccation before the initial  weighing, it is frequently
found that weight losses can occur when sampling clean air.
Previous tests were conducted to investigate this phenomenon
in detail.10  It was found that  with careful handling, weight
loss per glass fiber substrate for Andersen impactors can be
kept below 0.1 mg.  This loss is attributed to loss of fibers
which stick to seals within the  impactor and to "superdrying"
when sampling hot,  dry air.  Weight losses of 0.1 mg are  small
                               29

-------
compared to most stage catches when sampling particulate matter,
and they are within an acceptable range for sampling errors.

     A more significant problem is excessive weight gain of
the glass fiber material itself due to gas phase reactions.
These reactions appear to be caused by the SOx component in
flue gases.  A series of studies was thus directed toward de-
veloping procedures to passivate glass fiber materials against
the effect of SO  components in flue gas.
                X
     Although greases offer good impedance to particle bounce
on substrates, they are subject to temperature limitations.
Sampling clean, hot air while using greased substrates may
result in severe weight losses.  These losses appear to re-
sult from one or more of several mechanisms which may include
continued loss of volatile components, erosion of grease by
the action of the gas jet in the impactor, and occasional flow
of grease from the substrate to other surfaces within the impac-
tor.  In addition, chemical reactions may play a role in some
cases.  Occasionally, some of the weight lost on upper impactor
stages has been found to reappear as a weight gain on a back-up
filter, which is an indication that the grease has been blown
off the collection surface or has chemically reacted to form a
fine "smoke" which was then collected by the back-up filter.

Summary of Results of Evaluation of Greases

     Upon preliminary screening by static heating tests in
the laboratory, six of the nineteen greases tested were found
to have acceptable characteristics at elevated temperatures.
Among those greases eliminated by these tests, large changes
in mass or in consistency had occurred.

     In the field tests these six greases were applied to metal
foil impactor substrates and were subjected to a flue gas sampl-
ing procedure.  Particulate matter was removed by a prefilter so
that the effects of the flue gas alone on the greased substrates
could be observed.

     As a result of the field studies it was concluded that
Apiezon H grease performed best of the greases tested.  Other
greases studied displayed changes in consistency or a tendency
to flow under the influence of the gas stream.
      %
     Further tests on Apiezon H have demonstrated that this
grease is a suitable substrate material for applications where
the temperature does not exceed approximately 177°C (350°F).
                                30

-------
Summary of Results of Evaluation of Filter Media

     Untreated glass fiber filter materials used as  impactor
substrates will almost invariably increase in mass when sub-
jected to the hot flue gases normally encountered in  field
applications.  Conversion of SOa to various sulfates  appears
to be the cause of mass gains.  The various filter materials
tested vary widely in the amount of mass change which occurs
under a particular set of flue gas conditions.

     Preconditioning techniques can be  used to force  the produc-
tion of sulfates  in a filter medium, leaving a minimal number
of sites available for chemical reaction in the flue  gas, and
hence, providing  substrate material for which minimum mass
gains occur during use in an impactor.  The best results were
achieved when substrates were washed in sulfuric acid, baked,
and conditioned in situ.

     Of the filter materials studied, Reeve Angel 934AH was
found to be most  suitable in all respects  for use as  cascade
impactor substrates.

Conclusions and Recommendations

     Collection stages of most  types of cascade impactors are
very heavy  in comparison with the amounts  of particulate material
normally collected.  It  is  therefore the usual practice to
augment each collection  stage with a lightweight substrate
to improve  weighing accuracy.   Generally,  two classes of sub-
strates are used—greased metal foils,  and glass fiber filter
material.

     Greased foils provide  resistance to particle bounce and
scouring effects, but greases tend to be unstable at  elevated
temperatures.  Some tend to harden, and in others the viscosity
may become  reduced so that  they may flow or be blown  off the
surface by  the high velocity gas flowing through the  impactor
jets.  Of the greases tested, Apiezon H was found to  perform
most satisfactorily.  This  grease may be used at temperatures
up to approximately 177°C  (350°F).  No  greases were  found to
be usable at higher temperatures.

     Mass gains exhibited by glass fiber filter materials when
they are exposed  to the  SO  components  in  flue gas  streams
pose a complicated problem.  Experiments show  that  these mass
gains are caused  by formation of sulfates  due  to a  gas phase
reaction with SO  .  Laboratory  and field experiments indicate
that the only glass fiber  filter material  suitable  for use
as a cascade  impactor substrate is Reeve Angel 934AH. When
this material  is  acid treated,  according  to  a  procedure  given
below, mass  gains  caused  by  flue gas  reactions  can  be kept  quite
small.

                              31

-------
     It is recommended that acid washing, baking and in situ
conditioning be used whenever large blank mass gains with large
standard deviations are expected.  In this context, "large"
refers to glass fiber substrate mass gains greater than several
tenths of a milligram.

     Further research may provide a technique for passivating
glass fiber materials to all mass gains.  It has been suggested
that a high temperature polymer or silicon compound might be
developed to coat the glass fibers in much the same way that
the Gelman Spectro-Grade material is prepared for use at low
temperatures.

     The Final Report for this task was published in a document
entitled "Inertial Cascade Impactor Substrate Media for Flue Gas
Sampling," EPA-600/7-77-060, June 1977  (NTIS-PB 276 583/2BE).

Procedure for Acid Washing Substrates

     1.  Submerge the glass fiber substrates to be conditioned
in a 50-50 mixture  (by volume) of distilled water and reagent
grade concentrated sulfuric acid at 100°-115°C  (230-239°F)
for 2 hours.  This operation should be carried out in a hood
with clean glassware.  Any controllable laboratory hotplate
is suitable.

     The substrates may need to be weighted down to keep them
from floating.  For this purpose, place a teflon disc on the
top and bottom of the substrate stack.  The top disc can be
held down with a suitable glass or teflon weight*

     2.  When the substrates are removed from the acid bath
they should be allowed to cool to room temperature.  They are
next placed in a distilled water bath and rinsed continuously
with a water flow of  10-20/cm3/min.  The substrates should
be rinsed until the pH of the rinse water, on standing with
the substrates, is nearly the same as that of the distilled
water.  The importance of thorough washing cannot be over-em-
phasized.

     3.  After rinsing in distilled water the substrates are
rinsed in reagent grade isopropanol  (isopropyl  alcohol).  They
should be submerged and allowed to stand for several minutes.
This step should be repeated four to five times, each time
using fresh isopropanol.

     4.  Allow the substrates to drain and dry.  They can be
spread out in a clean dry place after they have partially dried
(dry enough to handle).
                                32

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     5.  When the filters are quite dry  to  the  touch  they  should
be baked in a laboratory oven to drive off  any  residual moisture
or isopropanol.  Bake the substrates at  50°C  (122°F)  for about
two hours, at 200°C  (392°F) for about two hours,  and  finally
at 370°C (700°F) for about three hours.  The  substrates are
now ready for in situ conditioning.

     As a final check, place two substrates in  about  50 ml
of distilled water,  and check the pH.  The  substrates to be
checked for pH should be torn into small pieces,  placed in
the water, and stirred for about 10 minutes before  the pH  is
measured.  If the pH is significantly lower than  that of the
distilled water, then the filters should be baked out at 370°C
(700°F) for several  hours more to remove any  residual sulfuric
acid.  The boiling point of sulfuric acid is  338°C  (640°F),
so high temperatures must be used.

     Figure 10  is a  flow chart representing the acid  wash pro-
cedure described in  the foregoing paragraphs.
                                33

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                             WASH SUBSTRATES IN
                             50% H2SO4 SOLUTION
                             RINSE IN WATER
                             (ROOM TEMPERATURE)
                              RINSE IN ISOPROPANOL
                              (ROOM TEMPERATURE)
                              DRY SUBSTRATES
                              IN AMBIENT AIR
                                BAKE OUT
                             RESIDUAL MOISTURE
                                                     pH TOO LOW
                                TEST pH OF
                                SUBSTRATES
                                 STORE IN
                               DESSICATOR FOR
                               ULTIMATE USE
.Figure 10.  Flow chart  for acid wash treatment of glass fiber filter  material.
                                        34

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DEVELOPMENT OF FIVE STAGE SERIES CYCLONE  SYSTEM

     The majority of measurements  to determine the particle-
size distribution in process streams are  made with cascade
impactors.  Impactors, however, have several limitations:

     • There is not enough mass collected for chemical anal-
       ysis of the particles in each size fraction.

     • Frequently there  is not enough mass collected on some
       stages to be weighed accurately.

     • Particle bounce and reentrainment  cause an unpredic-
       table, but significant, error in the stage and backup
       filter catches.11

     • When the mass concentration is high, the  sampling time
       may be undesirably short.

     • Impactors are used with lightweight collection substrates
       which are often unstable in mass when exposed to the
       process stream.12

     A series of cyclones with progressively decreasing cut
points will perform similarly to impactors, but  without many
of the associated problems.

     Cyclones, however,  also have  limitations to their applica-
bility:

     • There is no general theory  to describe the performance
       of small cyclones under field test conditions.

     • Sampling times may be undesirably  long at sources where
       the mass concentration is low.

     An experimental study was undertaken to develop and eval-
uate a system containing five cyclones and a backup filter
in series.

     The EPA-SoRI cyclone system as shown in Figure 11, is an
inertial particle sizing device that is designed for in-situ sampl-
ing of industrial process streams.  It will fit  through a 10 cm
diameter port and is equipped with nozzles of different diameters
to allow isokinetic sampling at a nominal sample flow rate of
28.3
     In this  study,  the  individual  cyclones  of  the  system were
tested and calibrated  in  the  laboratory  under conditions simi-
lar to those  frequently  encountered in field tests:   gas tem-
peratures of  25, 93, and  204°C,  flow rates of 7.1,  14.2, and
28.3 5,/min, and particle  densities  of 1.05,  1.35, and 2.04
gm/cm3 .

                               35

-------
-
                                   Figure 11.  EPA-SoRI Five Stage Cyclone.

-------
     The DSO cut points for the cyclone  system  at  various
operating conditions are given in Table  VI.   For laboratory
test conditions  (25°C, 28.3 2,/min, particle  density  1.0  gm/cm3)
the cut points for cyclones I-V are  5.4,  2.1, 1.4, 0.65, and
0.32 urn, respectively.  Figures 12 and 13  show  some  of  the
calibration curves that were obtained.   Figure  12  shows  effi-
ciency vs. aerodynamic  (particle density =1.0  gm/cm3)  par-
ticle diameter plots for a sampling rate  of 28.3 8,/min and Figure
13 shows similar data where the flow rate  is 14 &/min •  These
two figures illustrate that the small cyclones  have  "sharp"
efficiency curves and indicate that  the  system  should function
adequately as a  particle sizing device.   At  the test condi-
tions for Figure 12, the pressure drop across the  cyclone system
was 170 mm Hg.

     Data from this  study  wherein different_particle densities
(p) were used tend to support the DSO vs.  p   relationship
suggested by several theories.13'11*      On the  other hand,
the experimental results indicated that  the  cut points  were
directly proportional to the gas viscosity which is  in  oppo-
sition to most theories. i 3'1 **'i 5'1 &   Also, it was  found  in this
study and by Chan and Lippmann17 that the  Db0's of small
cyclones are not inversely proportional  to the  square root
of the flow rate as  some theories predict.

     A detailed  description of this  cyclone  system development
and calibration  program can be found in  "Development And Labora-
tory Evaluation  Of A Five-Stage Cyclone  System," EPA-600/7-
78-008, January  1978  CNTIS-PB 279 084/8BE).
                               37

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                                                        Table. VI

                                        LABORATORY CALIBRATION OF THE  FIVE-STAGE CYCLONES
                                                     Dso Cut Points
oo
    Cyclone

    Particle Density (gm/cm3)
      Flow
    7.1
   14.2
   28.3
   28.3
   28.3
Temperature
    °C
     25
     25
     25
     93
    204

2.04
5.9
3.8
4.4
6.4
I
1.00
(8.4)
(5.4)
(6.3)
(9.1)

2.04
2.4
1.5
2.3
2.9
II
1.00
(3.5)
(2.1)
(3.3)
(4.1)

2.04
Cyclon
(1.7)
.95
1.2
1.9
   III

   1.35
                                                                 1.00
   so cut points
micrometers
   2.1
(2.4)
(1.4)
(1.8)
(2.8)
IV
1.05
2.5
1.5
.64

1.00
(2.5)
(1.5)
(.65)

1.05
1.5
.85
.32
V
1.00
(1.5)
(.87)
(.32)
          cut points enclosed in parentheses are derived from the experimental data using Stoke's law.

-------
      100
 §
 £
 o
 UJ
 O
 O

 U
 u
 O
 O
• CYCLONE I
A CYCLONE II
• CYCLONE III
  CYCLONE IV
  CYCLONE V
                           PARTICLE DIAMETER, micrometer?
Figure 12.  Collection efficiency of the EPA-S.R.I. Cyclones at a flowrate
            of 28.3 H/m±n, a temperature of 25°C, and for a particle density
            of 1.00 gm/cm3.
                                    39

-------
     100
u
z
UJ
u
u.
U.
O
ui
O
U
   CYCLONE I
A  CYCLONE II
•  CYCLONE III
T  CYCLONE IV
   CYCLONE V
      20 —
                         PARTICLE DIAMETER, micrometers
 Figure 13.   Collection efficiency of the EPA-SRI Cyclones at a  flowrate
             of 14.2 £/min, a temperature of 25°C, and for a particle
             density of 1.00 gm/cm3.
                                   40

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ELECTROSTATIC PRECIPITATOR BACK UP  FOR  SAMPLING  SYSTEMS

     Filters used  to  collect  fine particles  in source  sampling
trains are troublesome  in several ways.   A large pump  is  usually
required to pull the  sample gas through a high efficiency filter,
and many tests are  terminated prematurely because of the  large
pressure drop that  results as a dust  cake builds up on the
filter as a result  of the filter cake being  less for small
particles.  This problem is especially  severe when the test
objective is to collect a large sample  of submicron particles.
Contamination of a  sample with filter material or physical
removal of the dust from the  filter can also be  problems.

     This program's goal was  to design  and evaluate the per-
formance of an electrostatic  collector  to be used as an alter-
native to filters  as  a  fine particle  collector.   Potential
advantages of an ESP  would be low pressure drop  and high  capacity.
Potential problems  would be unreliability and poor collection due
to back corona or  lack  of particle  adhesivity.

     The electrostatic  precipitator back up  filter was designed
to be operated at  a nominal sample  flow rate of  6.5 ft3/min.,
(184 £pm)  at a temperature of 205°C,  arid  to  achieve near 100% col-
lection of submicron  particles.  Since  it is possible  that there
would be a need to  operate the collector  in  situ, a secondary require-
ment was that the  collector pass through a 4 inch diameter
port.  Furthermore, the system was  designed  to be convenient
to operate and clean, and to  require  a  minimum of operator
training or attention.

     Figure 14 is a schematic diagram illustrating the main features
of the system that  was  designed and fabricated.   The collector is
of a cylindrical geometry with the  collection electrodes
arranged concentrically to allow a  large surface area  to  be
contained within a  relatively short outer cylinder.  Disc  and
needle discharge electrodes were designed and fabricated,  but
only the disc-cylinder  geometry was evaluated during this  pro-
gram.  The system  shown in Figure 14  is mechanically rugged
and the collection  electrode  geometry is such that the flow
is laminar at the  design flow rate; thus, it is  a simple  matter
to calculate particle trajectories  and  the electrode length
required for 100%  collection  efficiency.

     The ESP  back  up  is a highly  efficient collector of  sub-
micron particles.   When set to 200  yA on the corona disc  elec-
trode and 2 kV on  the collector  (both well below breakdown
values), no further adjustments are necessary for proper  opera-
tion.  The power supply developed for the ESP collector facili-
tates correct operation.  Since there is a potential for  de-
graded performance  due  to back corona if the collected par-
ticles are of high  resistivity, the collector can be routinely
used with a back up filter following  it in the sampling train.

                              41

-------
                                 SAMPLE IN
              0.32cm
         COLLECTION
         ELECTRODES
                                                         CORONA DISC
                                                         ELECTRODE
                                                           HIGH VOLTAGE
                                                           ELECTRODES
                                                           2kV
Figure 14.   Schematic of the electrostatic collector with the disc  discharge
             electrode installed.
                                  42

-------
If experience shows the system to operate reliably at a particular
source, the filter can be eliminated.


     After the sample is collected,  the ESP  is disassembled,
immersed in a suitable liquid, and agitated  ultrasonically.
The wash can be filtered or evaporated to dryness, depending
on the nature of the dust and the objectives of the test.

     The electrostatic collector prototype developed and tested
in this research effort fulfills the design  criteria:  near
100% collection of submicron particles when  operated at a nomi-
nal sample flow rate of 6.5 ftVrnin  and .a temperature of 200°C,
sized  to fit through a 4 inch diameter port  for in situ opera-
tion,  convenient to operate  and clean.

     Figure 15 shows a detailed assembly drawing of the elec-
trostatic precipitator back up.  A photograph of the complete
system is shown in Figure 16.  The report describing the develop-
ment of this device is entitled "An  Electrostatic Precipitator
Back Up For Sampling Systems," EPA-600/7-78-114, June 1978.
      We acknowledge that the disc-cylinder electrode geometry
 and method described in this report for ionization and particle
 charging are developments of Air Pollution Systems, Inc., Kent,
 Washington and the Electric Power Research Institute, Palo Alto,
 California, and that we have been advised by Air Pollution Sys-
 tems, Inc. that United States and Foreign patents have been ob-
 tained and others applied for.*  :

      We are not aware of the details of said patents or any
 pending applications and provide no assurance that practice
 of  any of the systems or methods disclosed in this report do
 not infringe either said patents or any other private rights.
 *U.S.  Patent No.  4093430
                              43

-------
                                                                Xf-~ A»T  fCis ffocfa^m
                                                                       SOUTHEM KSEAKH MSIITUTE
                                                                         tl«MINGHAM. AlAIAM* SS205
Figure 15.   ESP Collector  Assembly Drawing.

-------


Figure 16.  Electrostatic Precipitator Backup Filter.

-------
GUIDELINES FOR PARTICULATE SAMPLING IN INDUSTRIAL PROCESS  STREAMS

     The guideline document written under this technical direc-
tive lists and describes briefly many of the instruments and
techniques that are available for measuring the concentration
and/or size distribution of particles suspended in process
streams.  The standard, or well established, methods are de-
scribed as well as some experimental methods and prototype
instruments.

     Descriptions of instruments and procedures for measuring
mass concentration, opacity, and particle size distribution
are given.  Procedures for planning and implementing tests
for control device evaluation are also included.

     A bibliography at the end of  the report contains 141
citations to articles pertaining to the topics discussed in
the text.  These topics are listed below:

Mass Concentration
   Filtration
      EPA Test Method 5
      EPA Test Method 17
      ASTM - Test Method 17
      ASME Performance Test Code 27
      Advantages and Disadvantages
      Filter Materials
   Process Monitors
      Beta Particle Attenuation Monitors
      Piezoelectric Mass Monitors
      Charge Transfer
      Optical Methods
         Conventional Transmissometers
         Other Optical Methods
            Multiple-wavelength transmissometers
            Light scattering
Opacity
Particle Size Distributions
   Established Techniques
      Field Measurements
         Aerodynamic Methods
            Cascade impactors
            Cyclones
         Optical Particle Counters
         Diffusion Batteries with Condensation Nuclei Counters
         Electrical Mobility
      Laboratory Measurements
         Sedimentation and Elutriation
         Centrifuges
         Microscopy
         Sieves
         Coulter Counter

                                      46

-------
   New Techniques
      Low Pressure Impactors
      Impactors with Beta Radiation Attenuation Sensors
   Cascade Impactors with Piezoelectric Crystal Sensors
   Virtual Impactors
   Optical Measurement Techniques
   Hot Wire Anemometry
   Large Volume Samplers
Control Device Evaluation
Bibliography

     This document has been published as an EPA report entitled
"Guidelines for Particulate Sampling in Gaseous Effluents  from
Industrial Process Streams," EPA-600/7-79-028,  January 1979.
                              47

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TECHNICAL MANUAL FOR PARTICULATE SAMPLING EQUIPMENT AND METHODS

     This technical manual lists and describes the instruments
and techniques that are available for measuring the concentra-
tion or size distribution of particles suspended in gaseous
process streams.  The standard, or well established methods
are described as  are  some   experimental methods and pro-
totype instruments.  To the extent that the information could
be found, an evaluation of the performance of each instrument
is included.

     The manual describes instruments and procedures for mea-
suring mass concentrations, opacity, and particle size distri-
butions. It also includes procedures for planning and imple-
menting tests for control device evaluation, a glossary, and
an extensive bibliography containing 422 citations.

     In order to briefly convey the scope of this document
a list of the topics discussed is presented below.

Mass Concentration
   Filtration
      Introduction
      EPA Test Method 5
         Nozzle
         Probe
         Pitot Tube
         Particulate Sample Collector
         Gaseous Sample Collector
         Sampling Box
         Meter Box
         Performance
      ASTM - Test Method
      ASME Performance Test Code 27
         Isokinetic Sampling
      High Volume Samplers
      Filter Materials
      Summary
   Process Monitors
      Introduction
      Beta Particle Attenuation Monitors
         Instrument Development
         Performance
         Summary
      Piezoelectric Mass Monitors
         Performance
           ,Temperature
            Humidity
            Particle collection characteristics
            Linear response limit
            Considerations for stack application
         Summary
                               48

-------
      Charge Transfer
         Instrument Development
         Performance
         Summary
      Optical Methods
         Conventional Transmissometers
            Summary
         Other Optical Methods
            Multiple-wavelength transmissometers
            Light scattering
         Other Methods
Opacity
Particle Size Distributions
   Established Techniques
      Field Measurements
         Aerodynamic Methods
            Cascade impactors
            Cyclones
         Optical Particle Counters
         Diffusion Batteries with Condensation Nuclei  Counters
         Electrical Mobility
      Laboratory Measurements
         Sedimentation and Elutriation
         Centrifuges
         Microscopy
         Sieves
         Coulter Counter
   New Techniques
      Low Pressure Impactors
      Impactors with Beta Radiation Attenuation Sensors
      Cascade Impactors with Piezoelectric Crystal Sensors
      Virtual Impactors
      Optical Measurement Techniques
      Hot Wire Anemometry
      Large Volume Samplers
Control Device Evaluation
   Objectives of Control Device Tests
   Type and Number of Tests Required
   General Problems and Considerations
      Plant Location
      Laboratory Space
      Sampling Location and Accessibility
      Power Requirements
      Type of Ports
      Flue Gas Velocity and Nozzle Sizes
      Duct Size
      Gas Temperature and Dew Point
      Water Droplets and Corrosive Gases
      Volatile Components
      Process Cycles and Feedstock Variations
      Long and Short Sampling Times
      Planning a Field Test

                               49

-------
     This report has been published as: "Technical Manual:
A Survey of Equipment and Methods For Particulate Sampling
In Industrial Process Streams," EPA-600/7-78-043, March 1978
                              50

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EVALUATION OF THE PILLS IV

     The operating characteristics of  the PILLS  IV  in  situ
particle sizing instrument have been  investigated theoretically
and experimentally.  The  results of both types of work show
large errors in this instrument's ability to  size particles.
Attempts to correlate  the experimental findings  with qualita-
tive theoretical explanations have been successful.

     This prototype device is an extension of the PILLS  (Particu-
late Instrumentation by Laser Light Scattering)  technology to
fine particles designed by Environmental Systems Corporation,
Knoxville, Tennessee.  It measures particle size using the ratio
of intensities of light scattered from a particle at two small
angles  (14° and 7°) with  respect to an incident  laser beam.  The
intensity ratio was chosen as the sizing parameter because of
its relative independence of particle  refractive index.  However,
the magnitude of the scattered intensity at 14°  is also used for
several important decisions in the electronic processing logic,
which, for this particular optical system, render it especially
sensitive to refractive index and detector variations for the
determination of particle size distributions.  This investigation
established a sensitivity to particle  refractive index and detec-
tor response that seems to account for the observed characteristics
of the instrument.  Further measurements would be required to test
this explanation quantitatively.  Possible solutions to these
problems with only minor  hardware changes are offered in the pub-
lished final report entitled "Evaluation of the  PILLS IV," EPA-
600/7-78-130, July 1978.
                             51

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CYCLONE AND PRE-IMPACTOR FOR FUGITIVE AMBIENT  SAMPLING TRAIN

     Under this  task  Southern  Research  Institute designed and
calibrated the impaction preseparator stage and cyclone collector
of  the Fugitive  Ambient Sampling  Train  (FAST)  developed by The
Research Corporation  of New England  (Project Manager:   Mr.
Roland Severance).

     The FAST system,  shown in Figure 17, was  designed to operate
at  a flow rate of approximately 184 ACFM with  the impaction stage
designed to have a  95% collection efficiency for aerodynamic 15 ym
diameter particles  and thy cyclone collector designed  to have a 501
collection efficiency for 2.5  ym  diameter particles.

     In order to verify the 95% collection  efficiency  of the
impaction stage, ammonium fluorescein particles  with Stokes
diameters of 15  ym  and 10 ym were sampled.   To  verify  the
50% collection efficiency of the  cyclone collector, ammonium
fluorescein particles  with Stokes diameters  of  2  ym and  3 ym
were sampled.  The  impaction stage was  initially  evaluated
with pre-cut glass  fiber collection substrates.   After  this
system proved unsuccessful, two tests were performed using a
thin grease coating on the bare metal impaction plates.

     Figure 18 is a schematic  diagram showing the operating
principle of the Vibrating Orifice Aerosol Generator (VOAGl  used  in
this study.  A solution of known  concentration  [in our case,
a solution of fluorescein (C^oE12Os)  in O.IN^NH OH is  forcod
through a small  orifice (5, 10, 15, or  20 ym diameter)J,  The
orifice is attached to piezoelectric ceramic which, under
electrical stimulation, will vibrate at a known  frequency.
This vibration imposes periodic perturbations on  the liquid
jet causing it to break up into uniformly-sized droplets.
Knowing the liquid  flow rate and  the perturbation frequency,
the droplet size can be readily calculated.  The  solvent
evaporates from  the droplets leaving the non-volatile  solute
as a spherical residue.  The final dry particle  size can be
calculated from  the droplet size  through the known concentra-
tion of the liquid solution.

     To calculate the  dry particle size, the expression

                        /nr    vV3
                                      is used,
                          10 TTF
where GV is the solution concentration or volume of solute/
            volume of solution,
       Q is the solution flow rate (cm3/min), and
       F is the perturbation frequency (Hz).
                               52

-------
INLET
                        CYCLONE
VACUUM
PUMP
                                                                 EXHAUST
    Figure 17.  Schematic  diagram of Fugitive Ambient Sampling Train.
                                      53

-------
            COMPRESSED AIR LINE
Ui
                     REGULATOR
                       & TRAP


                  ^ | REGULATOR
                     DRYER

y
[REGULA
g VALV
[ROTOME
| DISF
ABSOLUTE
FILTER
TOR]
E (V) VIBRATING
y ORIFICE
1 GENERATOR
] IT
1 DILUTION AIR u
— H h—
'"*!""
sV-'
^t^^

1
•ERSION AIR



DUMP •*
SYRINGE
GENERATOf

1

                                                                           VALVE
                                                                                     FLOW DIVIDER

                                                                                                     MASS
                                                                                                  FLOWMETER
                                                                                      UNDER
                                                                                       TEST
                                                                                              COLD
                                                                                              TRAP
                                                                                                              EXHAUST
                       Figure 18.  Berglund-Liu type vibrating  orifice aerosol  generator system.

-------
     By the use of  smaller  orifices,  one  can  obtain  much  higher
operating frequencies.  This  in turn  yields higher particle
number concentrations and allows a  shorter running time to
collect the same mass per stage.  The running time must be
sufficiently long,  however, to  allow  accurate determination
of the collection efficiencies.   It was our experience that
the 20 urn orifice was consistently  easier to  use  in  particle
generation, primarily because of fewer clogging problems.

     Prior to particle  generation the orifices were  washed
in detergent with ultrasonic  agitation and then rinsed several
times in distilled  water, also  with ultrasonic agitation.  The
aerosol solution is fed from  a  syringe under  pressure provided
by a syringe pump.  As  a final  precaution for cleanliness, the
syringe is fitted with  a filter so  that the aerosol  solution is
filtered before it  is transported to  the  orifice.  After  the filter
and liquid handling system  were flushed several times with the
aerosol solution to be  used,  an orifice was placed,  still wet with
distilled water, or blown dry,  into the crystal holder, and the
syringe pump was turned on.   A  jet  of air was played over the
orifice to keep the surface clean until enough pressure was built
up behind the orifice to form a jet.

     After a  stream of  particles was  generated, a determina-
tion of monodispersity  had  to be made.  Two methods  were  used
to accomplish  this.  By using a small, well-defined  air jet
to deflect the  stream of  particles, it was possible  to tell
when the  aerosol  was  mono-  or polydisperse.   Depending on
particle  size,  the  stream was deflected by the air at differ-
ent angles, and if  the  aerosol  was  polydisperse,  several
streams could  be  seen at  one  time.  By varying the crystal
oscillation frequency,  the  system could be fine-tuned to  give
only a single  deflected particle stream,  thus indicating  mono-
dispersity.  On several occasions,  the aerosol tended to  drift
from monodispersity.  To  protect against  this occurrence, peri-
odic filter samples were  taken and  checked by optical micro-
scopy.  This  also provided  a  good check on the sphericity of
the aerosol because the final particles were   observed
instead of the  primary  liquid droplets.   The  microscopy thus
served as a check on  proper drying, satellites, correct size,
and multiplets.   Polonium 210 alpha particle  sources were placed
near the  air'stream as  charge neutralizers to reduce agglomera-
tion and  loss  of  particles  due  to electrostatic forces.   A
three-foot-high plexiglass  cylinder was placed on the generator
and dispersion  and  dilution air turned on to  disperse, dilute
and loft  the particles.  During each  test, filter samples were
drawn at  intervals  to insure  continued monodispersity.  Because
of its nonhygroscopicity  and  physical properties, ammonium
fluorescein was used  throughout these studies as  the test aero-
sol, although  in  theory,  any  material that will dissolve  readily
in an evaporable  solvent  could be used.   Figure 19  shows  one
of the test aerosols  generated with the VOAG.  In general,
it was found  that about 4%  to 8% by mass  of  the particles were
of twice  the volume (1.26 x diameter) of  the  primary particles.

                                55

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                                        €5
                 *   ,


Figure 19.   Ammonium fluorescein aerosol particles  generated using  the

            vibrating orifice aerosol generator.  The particle  diameters


            are 5.4 pm.
                               56

-------
     When it had been  determined  that  particles  of  the  correct
size were being generated,  the  FAST  was  allowed  to  sample  from
the VOAG outlet for  the  required  length  of  time  to  collect
a suitable sample.   Point  sampling was utilized  across  the
face of the louvered FAST  inlet.  On the majority of  the tests  the
VOAG outlet tube was situated at  eighteen different points.   Sampl-
ing duration at each point ranged from one  minute to  60 minutes
depending on the particle  size  being sampled.

     At the conclusion of  the sampling period, the  FAST was
carefully disassembled and all  surfaces  cleaned  with  a  solution
of 0.1N NIUOH.  Using  a  known amount of  the solution, each
surface was washed  to  dissolve  and rinse off the ammonium
fluorescein particles.  Where petroleum  jelly was used, a  small
amount of benzene was  poured over the  greased collection plate
in a small dish which  was  then  placed  in an ultrasonic cleaner.
A small amount of agitation caused the grease to dissolve  and
the ammonium fluorescein particles to  become well mixed.   Adding
a known abount of O.lN NH^OH to the  mixture with stirring  caused
the ammonium fluorescein to dissolve.  After the benzene mixture
floated to the top  of  the  NHi,OH,  the ammonium fluorescein  solu-
tion was pipetted off.


     The quantity of material on  each  surface was determined
by absorption spectroscopy.  A  Bausch  and Lomb Spectronic  88
Spectrophotometer,  calibrated with solutions of  known concentra-
tion of ammonium  fluorescein, was used to measure the concen-
tration of ammonium fluorescein in each  wash.  From knowledge
of the amount of  wash  solution, the  dilution factor,  if any,
and the absolute  concentration, the  mass of particles on each
surface could be  calculated. All particles from the  Louvers
to the Substrates were combined with the Impactor Catch.   All
particles from the  Substrate Support Plate  to the Cyclone  Cup
were combined as  the Cyclone Catch.  The remaining  material
was associated with the  Filter  Catch.  This scheme  of combin-
ing the dust from various  parts of the system is based  on  the
manner in which the system will be cleaned  after each field
test.  With the mass on  each surface known, the  collection
efficiencies could  be  calculated.

     During each  run the pressure drops  across the  cyclone,
filter, and blower  were  monitored as were  the ambient tempera-
ture and pressure.   All  data from the  individual tests  and
the calculated collection  efficiencies are  given in Table  VII.
The efficiency data are  plotted in Figure  20. The  D50  for
the cyclone is approximately 2.8  vim  aerodynamic  diameter.
The impactor was  not able  to achieve the 95% collection effi-
ciency' even with  a  grease  layer on the impactor  collection
plate.  Further study  will be  required to  satisfactorily
achieve the desired pre-separator performance.


                                  57

-------
                                                                                      Table  VII

                                                                     FAST IMPACTOR AND CYCLONE  CALIBRATION  DATA
                                                   15.0 Urn
                                           Concentration  (C) » 3.949 x 10"
Ul
00
          3
          o
          s
          iH
          s
               Date
               Measured  Particle Size
                 turn)  (p - 1.35 gm/cms)
               Impactor  Substrate Type*
              Temperature  (°C)
              Duration/point  (min)
              Total Duration  (min)
Louvres
Screen
Inlet Transform
Impactor Top Plate
Jet Plate
Substrates
Substrate Support Plate
Cyclone Inlet Transform
Cyclone  (Top)
Cyclone  (Body)
Catch Cup
Cyclone Outlet Tube
Filter Transform
Filter
Total Mass
•^
Impactor % Collection   50.1
  Efficiency
Cyclone % Collection
  Efficiency
6/20-21/78

)
*






1st
Sample
0.177
0.113
0.026
0.003
0.043
0.459
0.012
0.032
0.133
0.239
0.337
0.012
0.008
0.046
1.640
50.1
91.9
15.75

GF
3.1
22.0
2.3
21.0
1.0
45.0
2nd
Sample
0.183
0.116
0.035
0.000
0.054
0.469
0.012
0.023
0.144
0.265
0.342
0.011
0.004
0.040
1.698
50.5
93.5
6/22/78
14.07
GF
3.0
22.0
2.3
21.0
4.0
72.0
0.081
0.417
0.119
0.016
0.083
2.192
0.188
0.345
0.684
0.862
3.915
0.023
0.009
0.033
8.967
32.4
98.9
7/28/78
15.41
GF
2.65
22.0
2.3
21.0
4.0
72.0
0.077
0.365
0.267
0.015
0.060
1.800
0.077
0.237
0.390
3.511
0.713
0.627
0.022
0.499
8.660
29.8
81.1
8/1/78
14.72
Gr
2.7
22.0
2.2
21.0
4.0
72.0
0.167
0.446
0.042
0.005
0.022
6.766
0.066
0.125
0.419
1.190
1.884
0.045
0.019
0.043
11.239
66.3
97.2
10 Vim
1.171 x
8/10/78
10.72
Gr
3.0
20.0
2.2
21.0
3.0
54.0


0.089
0.368
0.071
0.009
0.015
5.709
0.026
0.041
0.108
0.226
0.159
0.016
0.006
0.016
6.859
91.3
93.6
9
10"2 C = 8.
6/12/78
10.05
GF
3.0
20.0
2.1
20.80
3.0
54.0
1st 2nd
Sample Sample
0.121 0.116
1.274 0.821
0.035 0.025
0.010 0.010
0.034 0.034
0.565 0.525
0.038 0.038
0.055 0.049
0.077 0.069
0.252 0.245
0.121 0.120
0.044 0.033
0.018 0.011
0.153 0.130
2.797 2,226
72.9 68.8
71.6 75.0
lira
531 x 10









1st
Sample
0.143
0.589
0.010
0.005
0.021
5.640
0.030
0.048
0.284
0.889
0.958
0.049
0.028
0.124
8.818
72.7
91.7

J C
6/15/78
10.72
GF
3.1
22.5
2.3
20.26
3.0
150.0
2nd
Sample
0.143
0.610
0.007
0.005
0.017
5.925
0.039
0.042
0.280
0.880
0.958
0.055
0.034
0.118
9.113
73.6
91.4
3 urn
= 3.161 x 10
6/26-30/78
3.0
GF
3.15
23.4
2.4
21.0
20.0
360.0


0.035
0.332
0.043
0.003
0.062
0.100
0.187
0.137
0.494
3.695
3.353
3.059
0.132
1.488
13.120
4.4
62.7
    2  urn
- 9.3662 x 10~

 7/20-26/78
     2.0

     Gf
     3.0
    22.8
     2.3

    21.0
    60.0
    18 his.
   0.019
   0.038
   0.025
   0.003
   0.025
   0.017
   0.034
   0.043
   0.072
   0.425
   0.756
   0.536
   0.202
   2.280
                                                                                                                                                               4.475

                                                                                                                                                               2.8

                                                                                                                                                              30.6
               *GF » Glass Fiber; Gr - Greased  (Vaseline and Toluene)

-------
Ul
vo
o

LU

O

EL
LU
LU

z
o


u
Ul
               o
               u
100





 90





 80





 70





 60





 50





 40





 30





 20





  10





   0
                      .3
                           1   I    1  I   I  I  I
                                     Impactor —
                                                1     I    I   I   I  I   I  I
                                 greased plates  O

                                 glass fiber substrates
                                     Cyclone —  A
                            1   J   I   I  I   I  I
                                                      I    I   I   I  I  1 I
             .5  .6  .7 .8 .9 1.0         2      3     456789 10



                            PARTICLE DIAMETER, MICROMETERS
                                                                                   20
                       Figure 20.  Collection efficiency versus particle diameter  for  the Fugitive Assessment

                                   Sampling Train  pre-separator impactor and cyclone.

-------
DESIGN, CONSTRUCT, AND EVALUATE OPTIMIZED CASCADE  IMPACTORS

     Based on the current knowledge of impactor operation  theory
and the results of field and laboratory testing of currently
available commercial and prototype cascade impactors by  Southern
Research Institute, high and low flow rate impactors are being
designed which will attempt to meet the criteria for optimized
cascade impactors.  An optimized cascade impactor  can be defined
as one which is designed to operate both in a laboratory and
field environment in such a way that the effects of particle
bounce, reentrainment, wall loss, non step function collection
efficiency curves, etc., are minimized.  Mechanical reliability
and ease of operation are also to be considered in the design
of these impactors.  Our criteria for optimized cascade  impactors
are listed in Table VIII.

     Design parameters for the 0.1,  0.5,  and 2.0 ACFM,  optimized,
cascade impactors have been generated by  a special computer
program written at Southern Research Institute.   Six impaction
stages with cut points of 9.6,  4.8,  2.4,  1.2,  0.6,  and 0.3
micrometers aerodynamic diameter were chosed as  a design goal
for these cascade impactors.   The actual  theoretical stage Dso's
as calculated by the computer program were very  close to the
desired stage cut points.  Identical stage cut points were not
realized because there was neither an unlimited  number  of holes
per stage available,  nor an infinite range of  drill sizes.   The
final design parameters are presented in  Tables  IX, X,  and XI.
An assembly drawing of the 0.5  ACFM impactor is  shown in Figure 21

     A prototype of the 0.5 ACFM optimized cascade  impactor is
to be fabricated by Southern Research Institute  for calibration
and testing purposes.
                             60

-------
          TABLE VIII-  CRITERIA FOR IMPACTOR DESIGN

1.   The jet Reynolds number should be between 100 and 3000.
2.   The jet velocity should be 10 times greater than the settl-
    ing velocity of particles having the stage Dso.
3.   The jet velocity should be less than 110 m/sec.
4.   The jet diameter should not be smaller than can be attained
    by conventional machining technology.
5.   The ratio of the jet-plate spacing and the jet diameter or
    width  (S/W) should lie between 1 and 3.
6.   The ratio of the jet throat length to the jet diameter (T/W)
    should be approximately equal to unity.
7.   The jet entries should be streamlined or countersunk.
                                61

-------
Impactor Sampling  Rate = 0.1 ACFM



Initial Guess of Stage D$o

Jet Inlet Pressure (atm)

Best Jet Drill Diameter  (cm)

Number of Jets on  this Stage

Actual Jet Reynolds Number

Jet Velocity (m/sec)

Actual Square Root of Stokes f

Cunningham Slip Correction Factor

Theoretical Stage  DSo (Mm)
                      Table  IX
    OPTIMIZED IMPACTOR DESIGN SPECIFICATIONS

         Gas Temperature = 204.0°C

                          Initial Cut Point Guess  (ym)

9,6              4.8
Particle Density = 1.0 gm/cc
                                                                 0.6
                          0.3
0.987
0.47
1
362.6
2.72
0.478
1.017
9.474
0.986
0.30
1
568.0
6.68
0.476
1.034
4.776
0.985
0.19
1
895.3
16.65
0.475
1.070
2.359
0.975
0.098
2
859.2
31.29
0.475
1.145
1.195
0.953
0.0254
31
209.0
30.05
0.480
1.297
0.589
0.921
0.0254
19
396.9
71.05
0.477
1.777
0.297

-------
                                                                       Table   X

                                                  OPTIMIZED IMPACTOR DESIGN SPECIFICATIONS


       Impactor Sampling Rate = 0.5  ACFM                  Gas Temperature = 204.0°C                       Particle Density = 1.0 gm/cc


                                                                               Initial Cut Point Guess (ym)


       Initial Guess  of Stage Dso


       Jet Inlet Pressure (atm.)


       Best Jet Drill Diameter  (cm)


       Number of Jets on this Stage


       Actual Jet  Reynolds Number

CT>
co     Jet Velocity  (ra/sec)


       Actual Square  Root of Stokes #


       Cunningham  Slip Correction Factor


       Theoretical Stage DSO
9.6
0.987
0.794
1
1073.6
4.77
0.474
1.017
9.221
4.8
0.986
0.518
1
1643.4
11.19
0.471
1.035
4.797
2.4
0.981
0.206
4
1030.1
17.75
0.474
1.070
2.372
1.2
0.970
0.107
8
981.5
32.99
0.474
1.146
1.212
0.6
0.931
0.025
155
204.4
30.05
0.480
1.304
0,588
0.3
0.901
0.016
235
206.9
49.95
0.480
1.707
0.316

-------
                                                                          Table XI
                                                      OPTIMIZED  IMPACTOR DESIGN SPECIFICATIONS

       Impactor Sampling Rate  =  2.0 ACBM                      Gas Temperature = 204.0°C.                         Particle  Density = 1.0 gra/cc

                                                                                    Initial Cut  Point Guess (urn)

       Initial Guess of Stage  DSO
       Jet Inlet Pressure (atm.)

       Best Jet Drill Diameter (cm)

       Numberof Jets on this Stage

cr\     Actual Jet Reynolds Number
*>
       Jet Velocity (m/sec)

       Actual Square Root of Stokes I

       Cunningham Slip Correction Factor

       Theoretical Stage  DSO
9.6
0.987
0.794
4
1073.6
4.77
0.474
1.017
9.221
4.8
0.986
0.404
8
1054.1
9.21
0.474
1.035
4.694
2.4
0.983
0.206
17
971.0
16.71
0.474
1.070
2.448
1.2
0.973
0.107
32
984.3
32.99
0.474
1.145
1.212
0.6
0.934
0.045
119
602.5
49.88
0.476
1.324
0.598
0.3
0.849
0.022
355
375.6
69.95
0.478
1.844
0.300

-------
U1
                                                                                                                          y/f^, &e>i jv^.^. . jj
                                                                                                                                    J -*/ ~?&fl-
                                                                                                                          Z/f~i 9aff. JW«» s/
                                                                                                                             SOUTHEBN DESiMCH INSIITim
                                                                                                                            	MUMINOHAM, AUIAMA 33205	
                                                                                                                                     • • S ~Z> //
                                     Figure 21.  Assembly  drawing of 0.5 ACFM optimized  cascade  impactor

-------
DESIGN A HIGH TEMPERATURE TEST FACILITY

     A particle sampling test facility has  been  designed.
An engineering drawing of the proposed test facility  is shown
in Figure 22.

     The facility will be used to simulate  the behavior of
various process streams.  Gas temperatures  will  be  variable
between ambient and 500°C (932°F).  Duct pressure will  be
variable from 0.7 atm to 1.0 atm, and gas velocity  will be
adjustable from 1.5 m/sec (5 ft/sec) to 15  m/sec (50  ft/sec).
This range of velocities is adequate to simulate most process
streams.  A  velocity range was chosen which is representative
of many process streams, and a duct size was chosen which would
keep the size and cost of piping/ within reason,  but not lead
to any objectionable blockage of the duct by any of the devices
to be tested.  A diameter of 30  cm  (12 inches) was  chosen.
This gives a resulting gas volume flow from 0.11 m3/sec
 (232 cfm) to 1.1 m3/sec  (2320 cfm).
     In order to have a low pressure system without excessive
pumping capacity, a closed loop system was selected.  However,
with a closed circuit, the dust must be removed after each
circuit so that control can be maintained over the test  aero-
sol.  Since a bag collector will be used, the temperature must
be reduced from the 540°C maximum test temperature to a  fea-
sible operation temperature for the collector, about 260°C
(500°F).  A cooler to cool down to 260°C plus a heater to heat
up to 540°C would be expensive to operate.  Therefore, an air-
to-air shell-and-tube heat exchanger was chosen to cool  the
air down to 260°C and then to heat it back up again to 455°C.
A temperature difference of about 85°C is needed to establish
good heat flow.  If too much insulation were used on the fan
and filter piping, there would be too low a temperature  dif-
ference, and the gas would not be cooled enough for the  sur-
vival of the filter bags.  Thus, it will be necessary to in-
stall the insulation on a trial basis, gradually increasing
the insulation to minimize the required reheat while making
sure that the bag temperature does not exceed 260°C.

     The size of the wind tunnel has been dictated by the size
of the apparatus to be tested.  The largest presently used
probe is about 10.2 cm (four inches)  in diameter; and if in-
serted into a 30.5 cm diameter pipe to 5 cm beyond the center-
line, the probe will obscure 27% of the open area.  It is
expected that impactors and cyclones would obscure a much
smaller area.  The required velocity times the area of the
test section gives the total volume of gas for determining
the size and cost of piping and ancillary equipment.


                              66

-------
Figure 22.  Preliminary layout for high temperature, low pressure wind tunnel test facility.

-------
     It will be necessary to provide sufficient strength  in
all components to withstand 0.35 kilogram per square centi-
meter of negative pressure.  Therefore, a cylindrical  heat
exchanger and cylindrical bag collector with reinforced top
cover will be required.  The circulating fan housing must be
stiffened, and the fan provided with a shaft seal good for 260°C
and 0.35 kg/cm2.

     Thermal expansion of the materials of construction must
be accommodated by either motion or stress.  Flexible  expan-
sion joints would have to be anchored solidly against  the
0.35 kg/cm2 suction forces, or solidly joined members  would
have to be anchored against extremely high expansion forces.
To reduce the magnitude of such forces, the design provides
for a symmetrically overhung, high temperature test section
in which the expansions either tend to compensate, or  merely
expand out into unrestrained space as a cantilever beam.   The
overhung, cantilevered weight is restrained by two guy wires
with turnbuckles.  These guys are supported by struts  to bring
the angle of the wires perpendicular to the direction  of expan-
sion so that negligible changes in alignment will occur.

     The thermal expansion of the connecting piping is accommo-
dated by using hinge type expansion joints which permit a  hinge
action in one plane without any axial change due to pressure
or vacuum.  Three such joints in a run of pipe are the equiva-
lent of a three hinged arch, which is statically determinate
and has zero built-in stress.

     The circulating fan will be solidly joined to the piping
from the dust collector, and the base will be mounted  on sliding
pads of oil impregnated  sintered bronze positioned to slide
parallel to the piping between the dust collector and  fan.

     Because the volumetric efficiency of a vacuum pump is
reduced by high temperature, low density gas, a water  jacketed
cooler will be used between the hot circulating loop and the
vacuum pump.  Simple coolers for air compressors are commer-
cially available.  The vacuum pump itself should be protected
against high temperatures resulting from cooling water failure,
and from dust carryover from torn bags, or from bag changing
operations.  Therefore, a fluid piston Nash vacuum pump was
selected to meet the above fail-safe conditions.  Because  the
vapor pressure of water is a half an atmosphere at 82°C, water
cannot be used as a compressant fluid.  Therefore, a recircu-
lated and cooled oil will be used as a compressant fluid.
                               68

-------
     The heat exchanger,  fan,  dust  collector,  and  vacuum pump
are bulky pieces of  equipment  and do not need  to be  inside
the building.  We therefore  chose to pierce  the building wall
in a third floor laboratory  and  to  locate everything  except  the
test section on a structural steel  platform  outside.  We selec-
ted a spiral access  stairway because a  ladder  is less safe
and a zig zag stairway  requires  more space-  A manual full
circle winch crane of 455 kg (1000  Ib)  capacity is included
for lifting the covers  off the dust collector  and  for raising
miscellaneous material  to the  platform.

     The test section is  furnished  with 15 cm  (6 inch) pipe
flanged access ports about 4,  6, and 8  diameters downstream
from the dust injection point.  Ports are arranged on all four
sides so that equipment may  be mounted  either  horizontally,
vertically, or through, (as  for  obscurometers  or for  Schlieren
photography).

     The SoRI POP 11/34A  Minicomputer Based  Data Acquisition
System will be used  for digital  display of the operating con-
ditions of the components of the facility as well  as  control
of the system.

     The conditions  to  be monitored are:

     1.  test section gas temperature;
     2.  test section pressure;
     3.  test section gas flow rate (using a venturi  meter);
     4.  temperature of the  device  under test;
     5.  pressure drop  across  the device under test;
     6.  gas flow through the  device under test;
     7.  gas temperature  at  the  inlet to the bag house;
     8.  pressure drop  across  the bag house;
     9.  gas temperature  at  the  outlet  of the  heater; and,
    10.  gas temperature  at  the  inlet of the vacuum  pump.

     Provisions will be made for multipoint  injection of a
test aerosol generated  by dispersion of dry  powder,  nebuliza-
tion, and high output generators of monodisperse aerosols.
Care will be taken  in design of  the injection  system to  insure
an even distribution of the  test aerosol through the  test sec-
tion of the  facility.   Included  in  the  available equipment are:
                                 69

-------
     1.   Climet Model 208 Particle Size Analyser modified
         for operation to 0.3 pm;
                                             /
     2.   Royco Model 225 Particle  Size Analyser;

     3.   a large particle dilution system;

     4.   a small particle dilution system;

     5.   Nuclear Data Model ND60 Multichannel Analyser for
         use with the above particle counters;

     6.   Lear Siegler Model RM41P  Transmissometer;

     7.   Thermo Systems Model 3030 Fine Particle Electrical
         Aerosol Analyser;  and,

     8.   Environment One Model Rich 100 Condensation Nuclei
         Counter with diffusion batteries.

     All control and monitoring equipment will be designed for
interfacing with a laboratory computer system.
                               70

-------
A MASSIVE VOLUME  SAMPLER FOR HEALTH EFFECTS STUDIES

     Today, there is  a  critical need for information pertaining
to the health effects of the particulate pollution emitted
from emerging alternative energy sources.   These data are obtained
from bioassay and animal inhalation studies conducted with
samples of  these  particulate emissions.   The extended time
periods needed  to perform these studies  requires large particu-
late samples.   The purpose of this task  was to design, fabricate,
and test a  sampling system which would collect large particulate
samples in  relatively short time periods.   In order to meet
this objective  a  sampling rate of 340 Nm3/hr (200 SCFM)  was
chosen.  Task requirements also demanded that the sampler also
separate the sample into two size fractions, a coarse fraction
and a  fine  fraction.  This necessitated   a  two  stage
sampler design.   Minimization of wall loss deposition at other
locations within  the system was also an  important considera-
tion.

     The ultimate goal  of this task was  that the particle size
distribution and  biological impact of the collected sample
should be an accurate representation of  the particulate emis-
sions  produced  by the energy source.  Fulfilling the particle
size distribution aspect necessitated building a traversing
sampler capable of near isokinetic sampling.  Accomplishing
the biological  impact goal required a sampler that would pre-
vent or minimize  contamination of the sample.  This was accom-
plished by  maintaining  flue gas temperatures in the sampler  thus
eliminating condensation of organic and  inorganic vapors in
the gas stream.   Also special materials  for construction were
used to minimize  sample contamination on the walls of the sam-
pler.  Since the  device  would be used at various sites, the
sampler had to  be built to make it readily movable from site
to site and conveniently adaptable to different site conditions.

     The prototype system (see Figure 23)  consists of a probe,
a cyclone dust  collector, fabric filter, flowmeter, blower,
and sampling/interconnecting line.

     The probe  is 2.1  m (7 ft.) long and possesses an adjust-
able opening at its insertion end to establish isokinetic sam-
pling.  The probe is capable of traversing and although it
is designed for a 9 cm  (4")  nominal port,  it can be easily
adapted to  larger ports.

     A Fisher-Klosterman XQ-5 cyclone with a calibrated cut
point  at 50% efficiency of 2.5 micrometers aerodynamic dia-
meter  at 340 Nm3/hr  (200 SCFM) is the initial particle collec-
tor.   The cyclone with  its heated enclosure measures approxi-
mately 2.1  m H  x  0.6 m  W x 0.6 m L  (61 H x 2' W x 2' L) and
weighs 91 kg  (200 Ibs).

                                  71

-------
-J
to
     PROBE
        DOTTED LINE: INSULATION, 2" THICK

        I" :  PRESSUR6 TAP
        ALL SAMPLING LINE (EXCEPT PROBE]

        IS 4.5" O.D. + 4" OF INSULATION
             Figure  23.
Schematic diagram of  massive volume sampler  for  Health
Effects  Studies.

-------
     Immediately following  the  cyclone is  a single chamber
fabric filter.  Its  dimensions  are approximately 2.1  m H  x
0.9 m W x 0.9 m L  (71  H  x 3'  W  x 3'  L)  and its  mass is 113  kg
(250 Ibs) .  It can accommodate  from 1 to 20 envelope  bags.
The filtration surface of the bags is composed  of Gore-Tex
porous teflon laminate;  the filtration surface  is backed  by
Nomex.  Each bag contributes 0.5 m2 (5.0 ft2) of collection
surface.  The fabric filter is  equipped with a  manual shaker
and can be easily modified  to become a double chambered,
automatic shaker design.

     The flowmeter  is an orifice plate type meter which is
used to monitor the  340  Nm3/hr  (200 SCFM)  flow  rate selected
for the sampler.  This 340  Nm3/hr (200 SCFM)  flow rate must
be stable in order  to maintain  the 2.5 ym  D50 of the  cyclone.
A hand operated damper attached to the outlet of the  blower
is used to adjust  the flow  rate.  At this  flow  rate the sam-
pler requires about  2% days of  continuous  sampling in order
to collect 1 kilogram of particulate matter from the  outlet
of an efficient control  device  with a particulate mass concen-
tration of 0.05 grams/Mm3  (0.2  gr/Nft3).

     The blower is  a centrifugal pressure  blower powered  by
a 3
-------
     Provisions exist to monitor both the temperature  and
pressure at the probe  and  at the inlet and outlet of  the
cyclone, fabric filter and blower.

     Design operating temperature of the sampler  is 204°C
(400°F).  Use of the sampler between the temperatures  of
204°C  (400°F)  and 316°C (600°F) may be possible.  This  would
depend on the effects of such temperatures on the sealing
integrity of the teflon gaskets, and the degree of degrada-
tion experienced by the fabric filter bag material.  Other
factors subject to the temperature of the gas stream are the
magnitude of the pressure drop presented to the blower  (the
static pressure available from the blower decreases with in-
creasing temperature), and the heating load placed on the
heaters.

     The construction of this sampler has been completed and
initial field tests will take place early in 1979.
                               74

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CALIBRATION OF  SOURCE TEST CASCADE IMPACTORS

     To the user  of  an inertial cascade impactor the most
important consideration is the degree to which the data
obtained will duplicate the actual particle size distribu-
tion sampled.   In order to transform the mass collected by
several impaction stages into a size distribution, an
accurate knowledge of the relationship between collection effi-
ciency and particle  size for each stage is essential.

     The impaction efficiency of a jet-plate system is defined
as the fraction of particles of a certain size in the jet that
impact on the collection plate.  The collection efficiency
of an impactor  stage, however, is the ratio of the mass (or
number) of particles of a certain size collected on an impac-
tion surface  to the  total mass (or number) of particles of
the same size  in a jet impinging on that surface-  The col-
lection efficiency is the product of the impaction efficiency
and the adhesion efficiency.5  The adhesion efficiency is the
fraction of  the number of particles that adhere to the surface
after touching  it by the impaction process, depending mainly
on the surface  characteristics of the particle and the collec-
tion surface.   Thus, there is disagreement between the theo-
retical impaction efficiency and the experimentally determined
collection efficiency in the cases where particle bounce, reen-
trainment, electrostatic effects, wall losses, and non-ideal
geometry have  an effect.  For this reason, the theory of impac-
tion may not  be sufficiently accurate in predicting impactor
performance.

     The theory of the impaction process has been developed
by several researchers18'19 to a state where the efficiency,
E, of  impaction can  be estimated as a function of the parti-
cle size  (Dp) ,  Reynolds Number (Re) , the jet diameter or width
 (Dj,W), the  jet to plate distance  (S) , and the jet throat
length  (T) .   (Marple19 specifically uses the dimensionless
reduced quantities  (D/Dj , S/W) and (T/D-j, T/W) when considering
the jet to plate distance and the jet throat length, respec-
tively. )


              E  = E  (D , Re, S/Dj. T/Dj)          (1)


     It is common practice to relate the particle diameter
D  to the square root of the inertial impaction parameter
 (ftp) , which  is  the ratio of the particle stopping distance
 (I) to the jet  diameter or width  (D^ or W) .  Thus,
                       \|> =


                                75

-------
or                                ^n n
                        \p  = D 2 1QP ° 	           (2)
                        y     p  18 y D.



where     C = Slip Correction Factor,
         V  = Jet Velocity (cm/sec),
          y = Gas Viscosity  (poise),
         pp = Particle Density (gm/cm3), and
         D. = Jet Diameter (cm).

     The square root of the  inertial impaction parameter,
is used in impaction theories as a dimensionless quantity pro-
portional to particle diameter,

                                     h
                                               (3)
     The inertial impaction parameter is useful in graphing
impactor calibration data because information from all stages
of an impactor can be placed on a single graph, and under many
circumstances would, in theory, lie along a common curve.
The value of /\|j at 50% collection efficiency, /^so, defines
the impaction stage D$o, which is the particle diameter for
which half of the particles are collected and half are passed
to the next stage.  In data reduction the Dg0 is used as the
effective stage cut diameter.

     Recently Marple19 has been able to calculate theoretical
impaction efficiency curves for several values of the jet to
plate distance, jet Reynolds Number, and jet throat length.
Figure 24 shows the results of these calculations for both
round and rectangular jet impactors.  It can be seen from
Figure 24 that for certain ranges of jet to plate spacing,
Reynolds Number, or jet throat lengths, the magnitude of
   o is sensitive to these parameters.
     In this study five source-test cascade impactors, all
of which are commercially available in the United States,
have been calibrated using monodisperse aerosols in order to
determine both their inertial sizing parameters and wall
losses as a function of particle size.

     A Vibrating Orifice Aerosol Generator was used to produce
monodisperse ammonium fluorescein aerosol particles 18 micro-
meters to one micrometer in diameter.  A Pressurized Cdllison
Nebulizer System was used to disperse Polystyrene Latex  (PSL)
and Polyvinyltoluene Latex (PVTL) Spheres 2.02 micrometers  to
0.46 micrometer in diameter.

                             76

-------
                  100
               o
               ui
               LL
               U.
               Ill
                        ±	L-JLJ	III! I   I J	1  I    I    i    I    I    I
                        1.1   0.2  0.3  0.4  0.5   0.6 0.7  0.8  0.9  1.0  1.1  1.2
                                           fmmmiimm.
                          (a) EFFECT OF JET TO PLATE DISTANCE (Re=3,000)
                 100
5  40
                  20
                            Re(S/Dj=1/2)
                             10 	
                             3,000-
                             25,000 •
^sjrsrs'~s'~ —
/"#/ V  / Re(S/W-1)  -
  ////  / - 10
  if - J. - 100
 ,'ff—f - 500
 ' t - - 3,000    -i
       - 25,000

       — — — Rectangular
           lll
                    0  0.1   0.2  0.3  0.4  0.5  0.6  0.7  0.8  0.9   1.0  1.1   1.2
                                          VSTTK
                           (b) EFFECT OF JET REYNOLDS NUMBER IT/WMI
                 100
                    0  0.1  0.2   0.3  0.4  0.5  0.6  0.7  0.8  0.9   1.0   1.1  1.2

                                          V STK
                             (c)  EFFECT OF THROAT LENGTH (Re-3,000)
Figure 24.  Theoretical  impactor efficiency  curves  for rectangular  and round
              impactors  showing  the effect of  jet-to-plate distance S,  Reynolds
              number Re, and throat length T.   Note that /STK  = D (Cp V0/9 yD.) /2,
              whereas v^ = D (Cp V0/18  yD )1/z .  After Marple.19
                                         77

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The impactors tested and their manufacturers  are:

     1.  Andersen Mark III Stack Sampler  (Andersen)
         Andersen Sampler, Inc.
         Atlanta, Georgia 30336

     2.  Brink Model BMS-11 Cascade  Impactor  (Brink)
         Zoltek, Inc.
         St. Louis, Missouri 63166

     3.  MRI Model 1502 Inertial Cascade  Impactor  (MRI)
         Meteorology Research, Inc.
         Altadena, California 91001

     4.  Sierra Model 226 Source Cascade  Impactor  (Sierra)
         Sierra Instruments, Inc.
         Carmel Valley, California 93924

     5.  University of Washington Mark III Source  Test
         Cascade Impactor (U. of W.)
         Pollution Control Systems,  Inc.
         Renton, Washington 98055

     The 5-stage Brink Impactor was  modified  to  include  an  in-
line cyclone pre-collector, a "0" stage,  and  a "6" stage.

     The Andersen impactor was used  with  glass fiber collection
substrates supplied by the manufacturer.  For the  Brink  impac-
tor a small disc of glass fiber material  was  used  as a sub-
strate as well as a thin grease layer  (petroleum jelly).  The
MRI and U. of W. impactors were tested with thin films of grease
(Petroleum jelly)  on the collection  plates.   The Sierra  was
operated with pre-cut glass fiber mats, supplied by the  manu-
facturer.

     Results were reported showing stage  collection efficien-
cies versus the square root of the inertial impaction parameter,
\|>, (see Figures 25 through 31)  and impactor wall losses  versus
particle size (see Figure 32).

Based on this work, several conclusions can be drawn.
     1.  The value of /4>5o  for each stage of a multiple  stage
impactor may be different.  (It has been the practice of  many
cascade impactor manufacturers and users to assume that the
value of /^so  for every stage was identical.  In many cases
the experimental value determined by Ranz and Wonglf was  used.)
                              78

-------
   99.8
o
z
UJ

o
01
UJ

_J
8   20  —
     0.03
0.05   0.08 0.1
0.6  0.8 1.0
2.0
Figure  25.  Collection efficiency vs. /t(J.  Andersen Mark III

             stack  sampler with glass fiber collection substrates,
                                 79

-------
    99.8
as


o
u
LU

z
o


o
LU
_J



8
     0.2
      0.03
0.05   0.08 0.1
  Figure  26.   Collection efficiency vs.  v^J.  Brink Model  BMS-11

               cascade impactor with glass fiber collection substrates.
                                 80

-------
   99.8
o
z
UJ

o

u.
LL
LU


O


O
UJ
O
O
     0.03
0.05   0.080.1
Figure 27.   Collection efficiency vs.  ^ .   Brink Model BMS-11

             cascade impactor with greased collection plates.
                                81

-------
99.8
 0.2
  0.03
Figure 28.  Collection efficiency vs.  v^J .   MRI Model 1502 Inertial
            cascade impactor with greased collection plates.
                                  82

-------
se
99.8



 99

 98


 95


 90


 80
\

H 70
O
E 60
u.
w 50
z
O
111
8
 40

 30

 20


 10
    2

    1

   0.5

   0.2
     0.03
                   TT
              STAGE  SYMBOL
                                I   IT
1
2
3
4
5
6
                                        I     III
          0.05   0.08 0.1
                0.2
                                         0.4   0.6 0.8 1.0
                                                             2.0
Figure  29.  Collection  efficiency vs. i^TT   Sierra Model 226 source
             cascade impactor with glass fiber collection substrates,

             Sampling flow rate is 14 LPM.
                                   83

-------
   99.8
a?


u

UJ

o
ul
u.
UJ


O


5
Ul
8   20  —
     0.03
 Figure  30.  Collection efficiency vs. v^j7 .  Sierra Model  226 source

              cascade impactor with glass fiber collection  substrates.

              Sampling flow rate is 7 LPM.
                                   84

-------
        99.8
    o
    o
    111
    _J
    o
    CJ
Figure 31.  Collection  efficiency vs.  v^ .   Universtiy of  Washington
            Mark III source  test  cascade impactor with greased  collection
            plate.
                                    85

-------
70 i 	
60 	
50 	
II III
1 1 1
V
o
1 1
o
A
0
A
C7 MMM
^9
A —
o
A
       20
          10
                                              O
                                              V
                                                        A
                                                        O
_i
<
a
A
*
o
                                     6
                                     8
                                              a
                                           *fi
                                                                 a
                                                                 A
                                                      D
                     1.5     2         3     4    5   6   7  8 9  10

                                PARTICLE DIAMETER, micrometers
                                                                       15
                                                     20
O
D
A
V
O
 ANDERSEN MARK III STACK SAMPLER. NONISOKINETIC SAMPLING.
 MODIFIED BRINK MODEL BMS-II CASCADE IMP ACTOR. GLASS FIBER SUBSTRATES.  NONISOKINETIC SAMPLING.
 MODIFIED BRINK MODEL BMS-II CASCADE IMPACTOR. GREASED COLLECTION PLATES. NONISOKINETIC SAMPLING.
 MRI MODEL 1502 INERTIAL CASCADE IMPACTOR. NONISOKINETIC SAMPLING.
 SIERRA MODEL 226 SOURCE CASCADE IMPACTOR. 14LPM.  NONISOKINETIC SAMPLING.
 SIERRA MODEL 226 SOURCE CASCADE IMPACTOR. 7LPM.  ISOKINETIC SAMPLING
 U. of W. MARK III SOURCE TEST CASCADE IMPACTOR. NONISOKINETIC SAMPLING.
         Figure  32.  Cascade  impactor wall  loss vs.  particle diameter.
                                          86

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     2.  The theories of cascade  impactor  operation  at  this
time do not describe the behavior  of  cascade  impactors  accu-
rately enough to obviate empirical calibration  of  each  device.

     3.  The stage collection  efficiencies are  sensitive  to
the type of impactor collection substrate  that  is  used.   This
dependence is evident in the comparison  of the  Brink Cascade
Impactor data using glass  fiber collection substrates and
greased collection plates.  The strong dependence  of collec-
tion efficiency on stage collection substrate material  has
also been illustrated and  discussed by Willeke20 and Rao.5

     4.  In the majority of cases  the stage collection  effi-
ciency never reaches 100%  for  any  particle size but  reaches
a maximum value that usually falls between 80%  and 95%.
Hence, some greatly oversized  particles  will  reach every
stage beyond the first  stage.  Unless suitable  compensation
can be made for the presence of these oversized particles,
their presence will tend to bias  the  apparent particle  size
distribution toward higher than actual concentrations of  fine
particles and reduced concentrations of large  particles.   The
errors probably tend to be more significant for the  fine  particle
end of the distribution.

     5.  The use of grease on  the  collection  plates  as  well
as a reduction in  the impactor flow rate tends  to  decrease
the magnitude of this problem. The Sierra impactor  data  illu-
strate the increase in  collection  efficiency  which resulted
from a decrease in sampling flow  rate and  concomitant reduc-
tion in bounce and cascading of large particles to lower
stages.  This study shows  that in  some cases  the maximum
efficiency was almost doubled  by  lowering  the flow rate.  A
discussion of this phenomenon  has  also been presented by  Rao.

     6.  All of these cascade  impactors  are roughly  equivalent
in performance, except  for the Sierra operated  at  14 LPM.  It
must be remembered, however, that  the type of substrate and the
sampling flow rate which are employed will cause some differences
in impactor operation as well  as  other possible factors asso-
ciated with sampling at industrial sites (temperature and pres-
sure extremes, particle density,  particle  adhesiveness, mois-
ture content, etc.).

     This work has been reported  in "Particulate Sizing Tech-
niques For Control Device  Evaluation: Cascade  Impactor Cali-
brations," EPA-600/2-76-280, October  1976  CNTIS-PB 262  849/3BE).
                              87

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CALIBRATION OF SOVIET PARTICLE SIZING INSTRUMENTS

     Under this task three Soviet cascade  impactors  and  one
Soviet impactor/cyclone were calibrated.   The  three  cascade
impactors included one twelve stage device and  two fourteen
stage impactors.  The three stage impactor/cyclone had a
single impaction stage followed by two cyclonic  stages.   All
four devices had an integral back-up filter holder which used
a plug of glass wool fibers.

     A photograph of one of the fourteen stage  Soviet impactors
is shown in Figure 33.  Figure 34 shows the Soviet impactor/
cyclone.  The upper stages of these sizing devices were  cali-
brated using ammonium fluorescein aerosols (20  ym to 2 ym)
dispersed by a Vibrating Orifice Aerosol Generator.  The lower
stages were calibrated using monodisperse polystyrene latex or
Polyvinyltoluene latex spheres (2.02 ym to 0.46  ym) dispersed by
a Pressurized Collison Nebulizer System.

Soviet Three Stage Impactor/Cyclone

     As mentioned above, this instrument consisted of a  single
impaction stage followed by two cyclonic stages.  A back-up
filter collected all particles passing the last  stage.   This
device was constructed from a titanium alloy. A  set of nozzles was
supplied with the impactor/cyclone.  All three  stages were
calibrated using monodisperse ammonium fluorescein particles
with sizes ranging from 18 micrometers diameter  to 2.3 micro-
meters diameter.  The ambient pressure was 29.5" Hg, the tem-
perature was 22°C, the particle density was 1.35 gm/cm3,  and
the sampling flow rate was 10 liters per minute.  At these con-
ditions the cut points of the three stages were  determined
to be 13.5, 6.4, and 2.6 micrometers.  The results are presented
graphically in Figure 35.

Soviet 12-Stage Cascade Impactor

     This impactor was unique in that several stages were de-
signed to have identical cut points.  Because of this feature,
the impactor had seven effective stages.  The twelve stages
were paired as follows:  1 and 2, 3 and 4, 5, 6  and 7, 8, 9
and 10, 11 and 12.  In field use the mass collected by single
stages 1 and 2 was combined as the catch for effective stage
1.   In a similar manner the mass collected by single stages
11 and 12 became the combined catch for effective stage  7.
The calibration conditions were an ambient pressure of
29.5" Hg, a temperature of 22°C;  the particle density was 1.35
gm/cm3 and the sampling rate was ten liters per  minute.   Be-
cause of the type of construction of this  impactor,  it was
only possible to calibrate it using ammonium fluorescein aero-
sols between 2 and 20 micrometers diameter.  The calibration data
are shown by stage both on an individual basis  (Figure 36)
and on an effective stage basis (Figure 37).

                              88

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Figure 33.  Soviet lA-stage cascade impactor.
Figure 34.  Soviet 3-stage  impactor/cyclone,
                               89

-------
100
  90
 10
   .5  .6.7.8.91.0        2      3    4   5  6 7  89  10

                 Particle  Diameter,  Micrometers
20
-Figure 35.  Collection efficiency vs. particle diameter.  Soviet 124-.stage
            impactor/cyclone.
            1 -  impaction stage 2 - 1st cyclone  3  - 2nd cyclone
            (29.5 in. Hg, 22°C, 1.35 gm/cm3, 10 LPM)
                                  90

-------
100
  90
    .5  .6.7.8.91.0        2      3   4    5  6  7  89  10

                 Particle Diameter, Micrometers
20
Figure 36. Collection efficiency vs. particle diameter.  Soviet  12-stage
           cascade impactor.   Data shown for the  first nine stages from
           2 to 20 microns.   (29.5 in. Hg, 22°C,  1.35 gm/cm3,  10 LPM).
                                    91

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  100
   90
   80
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          Soviet 14-Stage Cascade  Impactor  (Small D50's)
          Soviet 14-Stage Cascade  Impactor  (Large DSo's)

     These cascade  impactors were  similar  in  design  to  the
Soviet 12-Stage impactor  in that their  14  single stages were
divided into seven  effective stages  with a  pair of single
stages per effective  stage; each member of  a  pair is theoreti-
cally designed to have  the same cut  point.  These seven effec-
tive stages were numbered 1.1/1.2, 2.1/2.2, 3.1/3.2,  4.1/4.2,
5.1/5.2, 6.1/6.2, and 7.1/7.2.  In practice the mass collected
by individual stages  1.1  and 1.2,  for  example, was combined
to give a total mass  collected by  the  first effective stage.
This procedure was  repeated for the  rest of the impaction
stages.  These two  impactors had different  cut points but
shared identical stages on five of the  seven  effective  stages
as illustrated in the following chart.

                     14-Stage Cascade Impactor
               Small  Dsos              Large  DsoS
                                          7.1/7.2
      Effective stages 1,  2,  3,  4,  and 5 of the small  Dso  impac-
 tors  were  identical with  stages 1,  4, 5,  6,  and 7  of  the  large
 Dso  impactor,  respectively.   It was possible to calibrate both
 impactors  with ammonium fluorescein and polystyrene latex par-
 ticles;  however,  it was not  possible to complete the  calibra-
 tion  on  stages 7.1/7.2 of the small Dbo impactor since the
 pressure drop  across these stages was greater than our calibra-
 tion  apparatus could maintain.   The results of the calibration
 are  depicted graphically  in  Figures 38 and 39.
                                93

-------
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   80
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  .5 .6.7.8.91.0        2      3   4    5 6  7 89  10

               Particle Diameter, Micrometers
20
Figure 39. Collection efficiency vs. particle  diameter.  Soviet 14-stage
           cascade impactor.   (Large cutpoints)
           (29.5 in. Hg,  22°C, 1.35 fm/cm3,  10 LPM)
                                  95

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CALIBRATION OF THE  SOURCE ASSESSMENT  SAMPLING  SYSTEM CYCLONES

     Three separate Technical Directives  were  issued under
this contract covering various  aspects  of calibrating the SASS
cyclones.  A schematic of the SASS  instrument  is  shown in
Figure  40.  The  first technical directive called  for the  cali-
bration of the three cyclones at  ambient  temperatures and pres-
sures.

     The calibrations of the Large  (10  ym)  and Middle (3  ym)
Cyclones were performed using ammonium  fluorescein  aerosols
generated with Southern Research  Institute's Vibrating Orifice
Aerosol Generator  (VOAG).  Monodisperse ammonium  fluorescein
aerosols with diameters of 2, 3,  4, 5,  7.5, 10.5, and 14.5
micrometers were sampled at flow  rates  of 4 ACFM  and 3 ACFM.
These particles  have a density of 1.35  gm/cm3.  After sampling
for a sufficient length of time,  each cyclone was washed  with
a known amount of NHitOH to dissolve the ammonium  fluorescein
aerosol.  The total mass of the collected aerosol was deter-
mined using absorption spectroscopy.  The collection efficiency
of each cyclone  was calculated and plotted versus particle
diameter.  Figures  41 and 42 present  these Collection Effi-
ciency Versus Particle Diameter data  for  the Large  and Middle
Cyclones, respectively.
           The Small Cyclone  was calibrated using  Dow Corning
 polystyrene  latex   (PSL)  and  polyvinyltoluene  latex  (PVTL) spheres
 dispersed  with  the Institute's  Pressurized Collison Nebulizer
 System.  Using  an  auxiliary  pump, aerosols were pulled through
 the  Small  Cyclone  at two  flowrates,  3.1 ACFM  and  1.8 ACFM.   A
 Climet  Instruments Model  208A Particle  Analyzer was used  to
 measure the  number concentration of unit  density  0.82 ym and
 1.1  ym  diameter  PSL spheres  and 2.02  ym diameter  PVTL spheres up-
 stream  and downstream of  the Small  Cyclone.   The  collection  effic-
 iencies were calculated  and  plotted versus the particle diameter
 as  shown in Figure 43.

     Based on the results of this limited  calibration study,
it appeared that the cyclone D5 o cut point varied approximately
inversely with the  square root of the particle density as pre-
dicted by theory.

     The specific data obtained in this study were  extrapolated
to obtain cyclone Dbo's for four combinations of flow rate
and particle density (4 ACFM and 3 ACFM flow rates  and 1.00
gm/cm3  and  2.3  gm/cm3 particle densities).  The resulting
graphs  shown in Figure 44 indicate the  approximate  range  of
D5o  cut  points  which can be expected of the SASS cyclones
at temperatures near ambient.

     After  the  above ambient calibration  work was completed,
a recalibration of   the three cyclones of  the Source  Assessment
                                96

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    HEATER
  CONTROLLER
                   CONVECTION OVEN
                                         FILTER




MMHBBH1
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w







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1
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    DRY GAS METER
    ORIFICE METER
CENTRALIZED TEMPERATURE
 AND PRESSURE READOUT
    CONTROL MODULE
                             OVEN
                             T.C.
                               XAD-2
                               CARTRIDGE
                                     CONDENSATE
                                     COLLECTOR
                                                     ^"



                                                  /
                                                     GAS COOLER
GAS
TEMPERATURE
T.C.
IMP/COOLER
TRACE ELEMENT
COLLECTOR
1MPINGER
T.C.
                           10 CFM VACUUM PUMP
        Figure  40. Schematic of the Source Assessment Sampling System.

-------
00
                    100
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                                  1
                        .3   .4  .5 .6  .7 .8 .9 1.0        2      3     456789 10


                                              PARTICLE DIAMETER, MICROMETERS
                                                                           20
                   Figure 41.  Collection efficiency vs. particle diameter.   Large SASS  cyclone.

                               Particle density - 1.35 gm/cm3.

-------
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                                                                           20
                                               PARTICLE DIAMETER, MICROMETERS
                      Figure 42.  Collection efficiency vs.  particle diameter.  Middle SASS cyclone.

                                  Particle density - 135 gm/cm3.

-------
o
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114

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                   20




                   10
                          1    I   I   I  1  I  I
                                  3.1  ACFM
                          I   I    I
                                              17~1    |   Mill
                                                      1.8 ACFM
                                                   I    I   I   I  I  I  I
                              .5  .6  .7 .8 .9 1.0         2      3    456789 10


                                            PARTICLE DIAMETER, MICROMETERS
                                                                               20
                    Figure  43.  Collection efficiency vs.  particle  diameter.  Small SASS cyclone.

                                Particle density - 1.35 gm/cm3.

-------
I
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At
                                             345

                                           Micrometers
10
20
30   40
            Figure 44.  SASS cyclone cut points.   (At 23°C)

-------
Sampling System  (SASS)  at  400°F  and  4  SCFM  was  performed.
The previous calibration at 75°F and 4 ACFM gave  approximately
0.86  yin, 3.5 ym,  and  11.0  urn D50's for the  Small,  Middle,  and
Large Cyclones,  respectively.

      The calibration  of the Large and Middle Cyclones  was  per-
formed using ammonium fluorescein aerosols  generated with
Southern Research  Institute's Vibrating Orifice Aerosol  Genera-
tor  (VOAG).  With  the cyclones placed  in  a  heated  oven and
using a heated inlet  line, the temperature  of the  gas  stream
at the inlet to  the Large  Cyclone was maintained  at 400°F.
Particle integrity of the  ammonium fluorescein  at  high tem-
perature was a major  problem.  It appeared  that rapid  heating
of aerosol particles  which had not dried  sufficiently  after
generation caused  these particles to rupture creating  a  large
concentration of contaminating small particulate matter.   This
problem was alleviated  by  allowing the aerosol  to  come up  to
temperature more slowly.   A color change  in  the ammonium fluores-
cein  before and  after  heating was observed.  Microscopic obser-
vation also indicated  a possible crystalline change, causing
the integrity of the  dry ammonium fluorescein particles  to
be questioned.

     The Large Cyclone was modified  to try  to obtain a D5u
closer to the desired  10 micrometers.  This  modification in-
volved the removal of  the  vortex buster from the Large Cyclone
outlet.  Unfortunately, there was no apparent effect on  the
performance of this cyclone.  The data for  the  Large Cyclone
is shown in Figure 45.

     The Middle Cyclone was also modified in an attempt  to
obtain a Dso closer to the desired 3 micrometers.  This  was
done by reducing the  Middle Cyclone  inlet diameter from  0.62
inches to 0.53 inches.  The effect of this change  was  minimal
as can be seen in  Figure 46 and Figure 47 for the  Unmodified
and Modified Middle Cyclone, respectively.

     As a result of this laboratory  calibration, the approximate
DSO'S for the Large and Middle Cyclones at 400°F and 4 SCFM
are 15 micrometers and 4.4 micrometers, respectively.

     After considering the data obtained during this recalibra-
tion, it was felt  that the desired Dou's might  possibly  be
obtained by removal of the vortex busters in the collection
cups of the Large  and Middle Cyclones.   The  resulting  large
tangential velocities near the walls of these cups would re-
move a sufficient number of particles to cause  a significant
and measurable change in the cut points.
                                102

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o
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               U
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  10
                          1    I   I   I  I  I  I
1     I    I   I  I   I  I  I
                            1    I   I  I  I  1  I
                                     I
             I  I  I  I  I
                           .4  .5 .6  .7 .8 .9 1.0        2      3     456789 10


                                             PARTICLE DIAMETER, MICROMETERS
                                                                            20
                    Figure 45.  Collection efficiency  vs. particle diameter.  Large SASS cyclone.

                                (4 SCFM, 400°F,  1.00 gm/cm3)

-------
U

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LL
u.
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            I   I   I  I  I I  I
            I   I   I  I  I  I I
                                    I
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                .5  .6  .7 .8 .9 1.0         2      3    456789 10


                              PARTICLE DIAMETER, MICROMETERS
    Figure 46.  Collection efficiency vs. particle diameter.   Unmodified middle

                SASS  cyclone.  (4 SCFM, 400°F, 1.00 gm/cm3)
                                                                            20

-------
              O

              HI
              UJ
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  10
                        1    I   Mill
                          1   I   \  \  I  l i
                                   1
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                             .5 .6  .7 .8 .9 1.0         2     3     456789 10


                                           PARTICLE DIAMETER, MICROMETERS
                                                                          20
                  Figure 47.  Collection efficiency vs. particle diameter.  Modified middle
                              SASS cyclone.   (4 SCFM, 400°F,  1.00 gm/cm3)

-------
     On September 14, 1976, a meeting was  held  at  Research
Triangle Park to discuss the results of  the  recalibration
of the SASS train cyclones at 4 SCFM and 400°F.  It  was  de-
cided that the results of this study were  not sufficiently
conclusive to recommend changes in  the cyclone  construction
to obtain the desired cut points of 10,  3, and  1 micrometer
at operating conditions of 400°F and 4 SCFM.  Data were  pre-
sented indicating possible physical changes  in  the ammonium
fluorescein aerosol at high temperature.   Also  the shift in
the cyclone calibration curves at these  conditions was not
expected based on current cyclone operation  theories.

     It was concluded that calibration with  aerosols which
could withstand these high temperatures  should  take place.

     As a result of this meeting a decision  was made to  cali-
brate the Source Assessment Sampling System  Middle Cyclone
at 400°F and 4 SCFM.  Because previous tests have  indicated
ammonium fluorescein was unstable at 400°F,  a search was ini-
tiated for an aerosol with some or all of  the following  char-
acteristics:

     Non-toxic
     Stable at temperatures up to 500"F  or above
     Soluble in water or other non-toxic,  non-residue forming
        solvent
     Amorphous - dries to form solid, homogeneous  spheres  when
        dispersed in solution from a VOAG
     Known or easily measured density
     Has a definite, distinct absorption spectrum  peak for
        absorption spectroscopy measurement  between 400  NM
        and 900 NM.

     The initial search for such an aerosol  was unsuccessful,
so, ammonium fluorescein was used to determine  the D3U cut
points of the Middle Cyclone at 70°F, 200°F, and 350°F and
5.45 ACFM and the data obtained from these tests was used  to
extrapolate to determine the Dg0 cut point at 400"F.  This
method proved to be difficult when it was  found that ammonium
fluorescein particles smaller than 4 \im  in diameter were un-
stable at 350°F.   Attempts to alleviate  this problem were
largely unsuccessful.   Meanwhile the search  for an acceptable
aerosol was continued using commercially available dyes.

     Of several samples from three chemical  companies, du  Font's
"Pontamine"  Fast Turquoise 8 GLP dye was the first found to
satisfactorily meet the requirements listed  above.  A spectral


                              106

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analysis performed  on  a  dilute water  solution of  this  dye  in-
dicated a distinct  absorption  peak  at 622  nanometers.   Measure-
ments with a Helium-Air  pycnometer  gave a  density of 2.04  gm/cm3.
The sample seemed pure and  its stability at 400°F was  excellent.
The expansion problems encountered  with small diameter ammonium
fluorescein particles  were  absent.  Aerosol particles  made
from a solution  of  the dye  in  distilled water were very nearly,
if not perfectly, spherical..

     The calibration of  the SASS train cyclones was performed
using the Institute's  Vibrating Orifice Aerosol Generator  (VOAG).
The VOAG generated  monodisperse ammonium fluorescein particles
and turquoise dye particles with diameters from 2 micrometers
to 7 micrometers.

     Throughout  the testing, close  watch was kept on the tem-
perature and flow rate of  the  aerosol stream. Any discrepancies
were quickly corrected,  and readings  of all temperatures were
recorded periodically.  Therefore repeatability of the tests
and test results was  insured.

     After each  test,  the  cyclone and filter substrates were
washed to dissolve  and rinse off all  the aerosol  particles.
The wash solutions  used  were 0.1 N  NH.fOH for ammonium  fluores-
cein and a sodium bicarbonate  solution for turquoise dye.

     A Bausch and Lomb Spectronic 88  Spectrophotometer, cali-
brated with solutions  of known concentration of the aerosol
solute  (turquoise dye  or ammonium fluorescein) was used to
measure the absorbance of  the  wash  from the cyclone and the
filter.  From knowledge  of  the amount of wash solution, the
dilution factor, if any, and the absolute  concentration, the
mass of particles  in  the cyclone and  on the filter was calcu-
lated.  With these  two masses  known,  the collection efficiency
of the cyclone  for  that  particular  particle size  was calculated.

Results

     Table  XI  lists the D5o cut points of  the cyclone  at  various
conditions.  Figure 48 shows the collection efficiency curves
of the cyclone  when calibrated with ammonium fluorescein par-
ticles at 70°F,  200°F, and  350°F.  The D5o's obtained  from
these curves and plotted in Figure  49 indicate that the D50-
gas viscosity relationship  is  linear.  This does  not correspond
to Lapple's13 prediction that  Dsu would vary directly  with
the change in the  square root  of the  gas viscosity.

     Figure 50  shows  the collection efficiency of the  cyclone
for ammonium fluorescein particles  and turquoise  dye particles
when collected  under  similar conditions.  The relative differ-
ences between the  two  aerodynamic DSO cut  points  derived  from
the two curves  differ  from  the prediction  of Lapple's  equation
by only 7%.
                                 107

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                                        Table  XII

                          SASS Middle Cyclone Calibration Data
Material
Vortex
Bus ter    Temperature
   Flow Rate
   ft.3/min
Actual/S tandard
Dso  Physical    D5o  Aerodynamic
 Micrometers     Micrometers
Ammonium
Fluorescein
o Ammonium
00 Fluorescein
Ammonium
Fluorescein
Turquoise
Dye
Turquoise
Dye
Turquoise
Dye
IN

IN

IN

IN

OUT

IN
Ambient

200

350


OF

°F

Ambient

400

400

OF

op
5

5

5

5

6

6
.31 / 	

.41/ 	

AC I


.42/ 	

.50/4.00

.50/4.00
2

3

4

2

2

3
.8

.5

.2

.2

.5

.4
3

4

4

3

3

4
.3

.0

.9

.1

.5

.9

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       1001
        75V-
                       I        I     T
            AMMONIUM FLUORESCEIN

              070°F,5.37ACFM
              A200°F, 5.41 ACFM
              D350°F, 5.46ACFM
    35

    O

    —
    o
    u.
    u.
    m
   UJ
   _l
   _t
   O
   U
        50
        25
I  !  I
                                       I   I  I I  I
                      2       3    4   56789 10

                 PARTICLE DIAMETER, micrometers
                                               3630-007
Figure 48.  Collection efficiency - temperature relationship  SASS middle
             cyclone.  Ammonium fluorescein particle density = 1.35 gm/cm3
                             109

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                                  180         220

                                 VISCOSITY, poise x KT6
260
                                                        3630-011
Figure 49.  DSQ - viscosity relationship SASS middle  cyclone.   Ammonium -
            fluorescein particle density =1.35 gm/cm3.
                                     110

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                 100
                  80
               2 60
               o

               O
               U
                 40
                 20
                                     DENSITY COMPARISON
O AMMONIUM FLUORESCEIN —
  70°F, 5.45 CFM
O TURQUOISE DYE
  70°F, 5.42 CFM

   1     I    I   (  i  I  I
                               2      3    4    56789 10
                           PARTICLE DIAMETER, micrometers
                                                       3630-008
Figure  50. Collection efficiency - particle  density relationship SASS
            middle cyclone.  Ammonium fluorescein particle density =1.35 gm/cm3,
            Turquoise dye particle density =  2.04 gm/cm3.
                                     HI

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     Figure 51 shows the collection efficiency curves of the
cyclone when calibrated with turquoise dye particles with and
without the vortex buster in place.  It was determined using
Lapple's equation that the Dso cut point of the cylcone with
the vortex buster removed is 3.5 vim for 1.00 gm/cm3 particles,
which is within the acceptable range.
                               112

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100
                   TURQUOISE DYE
                   400°F, 4 SCFM
                 O WITHOUT VORTEX BUSTER

                 A WITH VORTEX BUSTER
                      I     I    I   I  I  I  I
                               5   6 7  8 910
           PARTICLE DIAMETER, micrometers
                                      3630-009
Figure 51.  Collection  efficiency at 400°F,  4 SCFM SASS  middle  cyclone.
            dye particle  density =2.04 gm/em3.
                                                            Turquoise
                    113

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PROCEDURES MANUAL FOR ELECTROSTATIC PRECIPITATOR EVALUATION

     A manual entitled "Procedures Manual for Electrostatic
Precipitator Evaluation," EPA-600/7-77-059, June 1977  (NTIS
PB 209 698/7BE) has been written.  The purpose of this pro-
cedures manual is to describe methods to be used in character-
izing the performance of electrostatic precipitators for air
pollution control.  A detailed description of the mechanical
and electrical characteristics of precipitators is given.
Procedures are described for measuring the particle size dis-
tribution, the mass concentration of particulate matter, and
the concentrations of major gaseous components of the flue gas-
aerosol mixture.  Procedures are also given for measuring the
electrical resistivity of the dust.  A concise discussion and
outline is presented which describes the development of a test
plan for the evaluation of an industrial precipitator.  Several
appendixes contain detailed information on testing methods as
well as a listing of the Federal Stationary Source Performance
Standards and Federal Source Testing Reference Methods.


     To give a better idea of the scope of this document
the contents listing is reproduced below.

INTRODUCTION
   ELECTROSTATIC PRECIPITATOR INSTALLATIONS
      Types of Electrostatic Precipitators
      Characteristics of Typical Precipitator Installations
      Parameters Which Govern Electrostatic Precipitator Operation
   PARTICULATE SAMPLING FOR ELECTROSTATIC PRECIPITATOR EVALUATION
      General Problems
      Particulate Mass Measurements
      Particle Sizing Techniques
      Particulate Resistivity Measurements
TECHNICAL DISCUSSION
   ELECTRICAL AND MECHANICAL CHARACTERIZATION OF AN ELECTROSTATIC
     PRECIPITATOR
      Electrical and Mechanical Design Data
      Collecting Electrode System
      Discharge Electrode System
      Electrical Power Supplies
      Rapping Systems
      Dust Removal Systems
   MASS EMISSION MEASUREMENTS
      General Discussion
      EPA-Type Particulate Sampling Train
      ASTM-Type Particulate Sampling Train
      ASME-Type Particulate Sampling Train
      General Sampling Procedures
                              114

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   PARTICLE SIZE MEASUREMENT TECHNIQUES
      General Discussion
      Inertial Particle Sizing Devices
      Optical Measurement Techniques
      Ultrafine Particle Sizing Techniques
   PARTICULATE RESISTIVITY MEASUREMENTS
      General Discussion
      Laboratory Determination of Particulate Resistivity
      In Situ Particulate Resistivity Measurement
   PROCESS EFFLUENT GAS ANALYSIS
      General Discussion
      Qualitative Gas Analysis
      Quantitative Gas Analysis
DEVELOPMENT OF TEST PLANS FOR ELECTROSTATIC PRECIPITATOR EVALUATION
   General Discussion
      Level A Evaluation
      Level B Evaluation
      Level C Evaluation

Appendix A - AEROSOL FUNDAMENTALS, NOMENCLATURE, AND DEFINITIONS

Appendix B - PARTICULATE MASS CONCENTRATION MEASUREMENTS

Appendix C - CASCADE IMPACTOR SAMPLING TECHNIQUES

Appendix D - SIZE DISTRIBUTIONS OF SUBMICRON AEROSOL PARTICLES

Appendix E - LABORATORY DETERMINATION OF PARTICULATE RESISTIVITY

Appendix F - IN  SITU PARTICULATE RESISTIVITY MEASUREMENTS

Appendix G - FEDERAL STATIONARY SOURCE PERFORMANCE REFERENCE METHODS

Appendix H - FEDERAL STATIONARY SOURCE PERFORMANCE STANDARDS
                                  115

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REVIEW OF DOCUMENTS AND REPORTS FURNISHED BY EPA

     During the course of this contract two documents furnished
by our Project Officer were critically reviewed.  Criticisms,
comments, and suggestions for improvement were returned to
the Task Officer in charge.  These documents were:

IERL-RTP Procedures Manual:  Level 1 Environmental Assessment
by J. W. Hamersma,  S. L. Reynolds, and R. F. Maddalone, EPA-
600/2-76-160a, June 1976.

Procedures For Cascade Impactor Calibration and Operation in
Process Streams by  D. Bruce Harris, EPA-600/2-77-004, January
1977.
                              116

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U.S.A.-U.S.S.R.  SCIENTIFIC  INFORMATION  EXCHANGE  PROGRAM

     Under  this  task  Southern  Research  Institute personnel
participated  as  consultants on particle sizing  in a  program
of technical  information exchange with  scientists in the
Soviet Union.  During July, 1976  particle sizing equipment
was prepared  and shipped to the Soviet  Union for a field  test-
ing program at a scrubber installed on  a metallurgical plant.
Mr. J.DJ. McCain of the Southern Res'earch Institute staff accompanied
several EPA staff scientists to the test site.   The  actual
field  test  took  place during August, 1976.  No  results have
been published as of  this date.
                               117

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EPA/IERL/PMB EXHIBIT BOOTH AT THE 1977 APCA ANNUAL MEETING

     On June 21, 22, 23, 1977, the Process Measurements Branch
of IERL/RTP supported an exhibit booth at the 70th Annual Air
Pollution Control Association Meeting in Toronto, Ontario,
Canada.  This 10" x 20'  booth used a color scheme of dark
blue booth back wall and side walls, light blue carpet, and
green draped tables.  Three tables along the back wall were
used for document display.  Two tables, one on each side,
were used to display hardware.  On the white I1 x 20' header
board in black letters was printed the following title:

          United States  Environmental  Protection  Agency
       Industrial Environmental Research Laboratory - RTF
                   Process Measurements  Branch

On either side of the title was an EPA LOGO in color.

     On the back wall were hung six 31 diameter discs which
briefly described the research and development efforts of the
six 1977 Task Level of Effort contractors for the PMB. . These
six contractors were Acurex/Aerotherm, Arthur D.  Little, Inc.,
Research Triangle Institute, Southern Research Institute, The
Research Corporation of New England, and TRW, Inc.   Representa-
tives from each of the contractors were at the booth on a rotat-
ing basis to answer technical questions.

     The hardware on display included a complete Source Assess-
ment Sampling System, a KLD Droplet Analyser, and a Five Stage
Series Cyclone and IERL/PMB Advanced Sampling System.

     Approximately 200 copies each of twenty-one EPA Research
and Development Reports were distributed on a first-come, first
served basis to the 4200 registrants at the meeting.

     The following is a list of the documents which were dis-
tributed:

     HP-25 Programmable Pocket Calculator Applied to Air Pollu-
     tion Measurement Studies:  Stationary Sources.  EPA-600/7-
     77-058, June 1977

     Procedures Manual for Electrostatic Precipitator Evalua-
     tion, EPA-600/7-77-059, June 1977

     Industrial Environmental Research Laboratory - RTF Annual
     Report 1976

     Flow and Gas Sampling Manual.  EPA-600/2-76-203, July
     1976

     IERL-RTP Procedures Manual:  Level 1 Environmental Assess-
     ment.  EPA-600/2-76-106a, June 1976

                              118

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Selection and Evaluation of Sorbent Resins for the Collec-
tion of Organic Compounds.  EPA-600/7-77-044, April 1977

Technical Manual for Measurement of Fugitive Emissions:
Upwind/Downwind Sampling Method for Industrial Emissions.
EPA-600/2-76-089ar April 1976

Technical Manual for the Measurement of Fugitive Emissions:
Roof Monitor Sampling Method for Industrial Fugitive Emis-
sions.  EPA-600/2-76-089b, May 1976

Technical Manual for Measurement of Fugitive Emissions:
Quasi-Stack Sampling Method for Industrial Fugitive Emis-
sions.  EPA-600/2-76-089c, May 1976

Technical Manual for Process Sampling Strategies for Organic
Materials.  EPA-600/2-76-122, April 1976

Technical Manual for Analysis of Organic Materials in
Process Streams.  EPA-600/2-76-072, March 1976

Particulate Sizing Techniques for Control Device Evalua-
tion:  Cascade Impactor Calibrations.  EPA-600/2-76-280.
October 1976

Inertial Cascade Impactor Substrate Media for Flue Gas
Sampling.  EPA-600/7-77-060, June 1977

Operating and Service Manual:  Source Assessment Sampling
System.  Acurex/Aerotherm Report UM-77-81, March 1977

Environmental Assessment Sampling and Analysis:  Phased
Approach and Techniques for Level 1.  EPA-600/2-77-115,
June 1977

Procedures for Cascade Impactor Calibration and Operating
in Process Streams.  EPA-600/2-77-004, January 1977

Technical Manual for Inorganic Sampling and Analysis.
EPA/2-77-024, January 1977

Development and Trial Field Application of a Quality Assur-
ance Program for Demonstration Projects.  EPA-600/2-76-
083, March 1976

HP-65 Programmable Pocket Calculator Applied to Air Pollu-
tion Measurement Studies:  Stationary Sources.  EPA-600/8-
76-002, October 1976.

Process Measurements- Branch:  Report Listing, June 1,
1977

                            119

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     Pollution Control Technology and Environmental Assessment;
     Brochure Describing the Research and Development Efforts
     of the Six PMB Contractors

     At the conclusion of the exhibit all of the reports had
been given out, except for a few HP-65 booklets.  Reaction
to the exhibit by the attendees at the meeting was quite favor-
able.
                               120

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CALIBRATION OF A  SASS MIDDLE  CYCLONE  FOR  THE  HEALTH  EFFECTS
RESEARCH LABORATORY/RTF

     Exxon Research  and  Engineering Corporation  used a  Source
Assessment Sampling  System  at a  coal-fired  power plant  in
Paducah, Kentucky early  in  1977.   This  work was  performed
for the Health Effects Research  Laboratory  of the National
Environmental Research Center/RTF.  The SASS  was used to size
and sample the particulate  effluent.   In  order to determine
the actual Middle Cyclone D5o as run  Southern Research  Insti-
tute was requested to calibrate  the actual  SASS  Middle  Cyclone
used by Exxon at  the actual sampling  conditions.

     Exxon used the  following sampling  conditions.

       600°F inlet gas temperature to the oven
       Oven temperature  375°F
       No filter  element in the  filter  housing in the heated
         oven
       Pump flow  wide open  with  filter  on pump inlet and muf-
         fler on  pump outlet
       Vacuum measured ahead  of  pump  filter - 14 inches EzO
         vacuum under sampling conditions
       Stack moisture 8%
       Gas temperature in middle cyclone  unknown
       Vortex busters in the  collection cups  of  the  Large and
         Middle cyclones

These conditions  and those  of the calibration system were not
completely compatible.   The inlet gas temperature was 450°F,
the constraint being the temperature  limit  of the calibration
aerosol.  The oven temperature was 375°F.  The humidity of
the air was not measured.

     No probe was supplied  with  the cyclones; however,  a tele-
phone conversation revealed that Exxon  used an Aerotherm probe
which was twelve  feet long.  The sampling line of this  probe
is one-half inch  O.D. Stainless  Steel tube.  The heat loss
through this probe in our lab was unacceptable,  and  the par-
ticle loss would  probably be  quite high.  Also a filter had
to be used in the filter holder  so that all the  mass would
be caught for collection efficiency determinations.   Therefore,
the flow rate at  the inlet  of the large cyclone  had  to  be de-
termined.  The field set-up was  duplicated  as closely as possi-
ble and the flow  was measured to be 13  ACFM at an oven  inlet
temperature of 399°F.  Then the  probe was removed and a glass
fiber filter was  added to the filter  holder.   The flow  was
adjusted so that  the inlet  flow  to the  cyclones  was  13  ACFM.
There was a definite but unknown amount of  water in  the air.

     A note should be made  as to the  conditions  of the  cyclones
when they arrived.   There were a few  dents  in the cup and  the

                               121

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inlet of the Middle cyclone was bent such that the air  stream
did not enter the cyclone strictly tangentially.  The only
modification made to the cyclones by  SoRI  was replacement
of some teflon gaskets which were badly deformed.

     The calibration system used was a Vibrating Orifice Aerosol
Generator with du Pont "Pontamine" Fast Turquoise 8 GLP dye
as an aerosol.  The collected particles were washed off the
cyclones and filter with a sodium bicarbonate solution, and
their mass was determined with a spectrophotometer .

     For a temperature of 450°F, a flow of 13 cfm, and  a parti-
cle density of 2.04 gm/cm3, the Dso cut points of the large
and middle cyclones were 7.6 urn and 2.13 ym, respectively  (see
Figure 52).  For a particle density of 1.00 gm/cm3 and  the
same conditions, the Dso cut point of the large and middle
cyclones would be 11 urn and 3.0 ym, respectively.

Estimation of D50 of Middle Cyclone at 600°F
The
             cut point for the Middle cyclone is 3.0 urn for
a temperature of 450°F, a flow rate of 13 CFM, and a particle
density Of 1.00 gm/cm3, with the vortex buster in place.  Ex-
perimental work with the middle cyclone has indicated the
following may be obtained by extrapolating the DSO vs. vis-
cosity curve.
Flow Rate

5.4 CFM
5.4 CFM
5-4 CFM
             Dso
           5.0 ym
           5.8 ym
           6.2 ym
Temperature

    375"F
    450°F
    600°F
Particle Density

  1.00 gm/cm3
  1.00 gm/cm3
  1.00 gm/cm3
Assuming that the D5o cut point will increase at the same  rate
with increasing temperature at flow rates of 5.4 and 13.0  CFM,
the following relationships are obtained.
             Dso (600°F; 13 CFM)
             Dso (450°F; 13 CFM)
and
             P-JUL
             DSO
            (375°F;  13 CFM)
            (450°F;  13 CFM)
                              D50 (600°F; 5.4 CFM)
                              DSO (450°F; 5.4 CFM)
    Dso (375°F; 5.4 CFM)
    DSQ (450°F; 5.4 CFM)
Thus,
                             122

-------
    100
 0)
 a
 Ik
u
z
LU
o
u.
y.
LU
2
O
t~
U
LU
O
O
           	1	

            O NOZZLE
            A LARGE CYCLONE
            Q MIDDLE CYCLONE
     80
60
50
40
     20
     Temperature = 450°F
     Particle Density = 2.04 gm/cm^
     Flow = 13 ACFM
      1.0
                                5.0          10.0

                 PARTICAL DIAMETER, micrometers
20.0
             Figure 52.  Exxon SASS  cyclones.
                             123

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             Dso (600°F, 13 CFM) = 3.0 X |^  = 3.2  ym.

and

             D50 (375°F; 13 CFM) = 3.0 x |^-|  = 2.6  ym.

Therefore, the D50 cut points of the middle cyclone  for  a  flow
rate of 13 ACFM were estimated to be 2.6 ym for a temperature
of 375°F, and 3.2 ym for a temperature of 600°F.

Estimation of Dso of Small Cyclone at 600°F

     The small cyclone has previously been calibrated at two
flows:

  Flow          Dso          Temperature        Particle Density

1.8 ACFM        1.88             77°F             1.00 gm/cm3
3.1 ACFM        1.11             77°F             1.00 gm/cm3

Using this relationship Dso = KQ  from Chan and Lippmann17

                       Dh0  (1.88)      K  (1.8)N
                       D50  (1.11)      K  (3-1)N

                               N  = -0.97

So
                             1.88 = K  (1.8)~°'97

                                K = 3.32

Assuming the Dsu  vs. Q relationship above holds at Q = 13 ACFM,
                                         —n QT
                              D   = 3.32Q U'y/

                                  = 3.32(13)~°*97

                                  = 0.277 ym.

     Recent experimental work with the Five Stage Series Cyclone
II (which has identical dimensions as  the SASS small cyclone
except for the width and depth of the  cup) has indicated the
following
                                124

-------
Flow

1 CFM
1 CFM
1 CFM
  DSO
2.30 ym
5.21 ym
4.11 ym
Temperature

     77°F
    600°F
    375°F
Particle Density

  1.00 gm/cm3
  1.00 gm/cm3
  1.00 gm/cm3
     Assuming  that  the D5o  cut point will increase at the  same
rate with  increasing  temperature at flows of 1 and 13 CFM,
we obtain  the  following relationships:

                    DSO (600°F; 13 CFM)   _  Dso (600°F,  1 CFM)
                    DSO  (77°F;  13 CFM)
                              Dso (77°F, 1 CFM)
and
                    Dso  (375°F;  13 CFM)
                    Dso  (77°F;  13 CFM)
                              Dso  (375°F; 1 CFM)
                              Dso  (77°F; 1 CFM)
      Thus,  the DSO  cut points of the small cyclone for a flow
of  13  ACFM  were estimated to be 0.49 ym for a temperature of
375°F  and 0.63 ym for a temperature of 600°F.
                                 125

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PROCEDURES MANUAL FOR FABRIC FILTER EVALUATION

     The procedures manual for the evaluation of fabric filters  (bag-
houses)  has been published under the title "Procedures Manual  for
Fabric Filter Evaluation." EPA-600/7-78-113, June 1978  (NTIS-PB
283 289),
     The purpose of this procedures manual was  to describe
methods to be used in experimentally characterizing  the performance
of fabric filters for pollution control.  A detailed description
of the mechanical characteristics of fabric filters  is  presented.
Procedures are described for measuring the particle  size  distri-
bution, the mass concentration of particulate matter, and the
concentration of major gaseous components of the flue gas-par-
ticle mixture.  A concise discussion and outline is  presented
which describes the development of a test plan  for the  evalua-
tion of a fabric filter installation.  By following  this  outline
useful  tests may be performed which range in complexity from
qualitative and relatively inexpensive to rather elaborate
research programs.

     In order to detail the scope of this document the Table
of Contents is reproduced below,

INTRODUCTION
   FABRIC FILTER INSTALLATIONS
      Particle Filtering Mechanisms
      Factors Affecting Filter Performance
      Filter Fabrics
      Types of Fabric Filters

   PARTICULATE SAMPLING FOR FABRIC FILTER EVALUATION
      General Considerations
      Particulate Mass Measurements
      Particle Sizing Techniques

TECHNICAL DISCUSSION
   MECHANICAL CHARACTERIZATION OF A FABRIC FILTER INSTALLATION
      Mechanical Design and Operating Data
      The Fabric Filter Bags
      Filter Fabrics
      Dust Removal Systems
      Baghouse Operation-General Maintenance Considerations

   MASS EMISSION MEASUREMENTS
      General Discussion
      EPA-Type Particulate Sampling Train  (Method 5)
      ASTM-Type Particulate Sampling Train
      ASME-Type Particulate Sampling Train
      General Sampling Procedures
                               126

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   PARTICLE SIZE MEASUREMENT TECHNIQUES
      General Discussion
      Inertial Particle Sizing Devices
      Optical Measurement Techniques
      Ultrafine Particle Sizing Techniques

   PROCESS EFFLUENT GAS ANALYSIS
      General Discussion
      Qualitative Gas Analysis
      Quantitative Gas Analysis

DEVELOPMENT OF TEST PLANS FOR FABRIC FILTER EVALUATIONS
   OBJECTIVES OF CONTROL DEVICE TESTS
   TYPE AND NUMBER OF TESTS REQUIRED
      Fabric Filter Level A Evaluation
         Plant Operating Data
         Baghouse-Fabric Filter Design Data
         Flue Gas Characteristics, Baghouse AP, Maintenance Data
      Fabric Filter Level B Evaluation
         Quantitative Gas Analysis
         Inlet and Outlet Mass Concentration Measurements Total
           Mass Collection Efficiency
      Fabric Filter Level C Evaluation

   GENERAL PROBLEMS AND CONSIDERATIONS
APPENDICES

Appendix A

Appendix B

Appendix C

Appendix D

Appendix E

Appendix F
AEROSOL FUNDAMENTALS, NOMENCLATURE, AND DEFINITIONS

PARTICULATE MASS CONCENTRATION MEASUREMENTS

CASCADE IMPACTOR SAMPLING TECHNIQUES

SIZE DISTRIBUTIONS OF SUBMICRON AEROSOL PARTICLES

SUMMARY OF SOURCE PERFORMANCE METHODS

FEDERAL STATIONARY SOURCE PERFORMANCE STANDARDS
                               127

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ADVANCES  IN  PARTICLE  SAMPLING AND MEASUREMENT SYMPOSIUM

       Southern Research Institute  coordinated a  symposium for the
Process Measurements  Branch/IERL-RTP on  May  15-17,  1978 at  the
.Grove Park Inn and Country Club,  Asheville,  North Carolina.   The
number of attendees was  176.   There  were five sessions  with
a total of seventeen  speakers.  The  symposium had morning
and  evening  sessions  with the afternoons free for recreation.
A proceedings from this  technical meeting has been  published.
The  scope of the  meeting  can  be seen in  the  following reprint
of the technical  program.

                                  TECHNICAL PROGRAM


              ADVANCES IN PARTICLE SAMPLING AND MEASUREMENT

                   A Symposium Sponsored by The Process Measurement Branch,
                         Industrial Environmental Research Laboratory,
                           U.S. Environmental Protection Agency,
                           Research Triangle Park, North Carolina.
    MONDAY MORNING, MAY 15

                     SESSION I: INSTRUMENTS AND TECHNIQUES FOR
                               PARTICLE-SIZE ANALYSIS


     8:30 am  Welcome Address - John K. Burchard (EPA), Director, Industrial Environmental
             Research Laboratory - RTP
     8:40     Opening Remarks • Symposium Chairman, D. Bruce Harris (EPA/I ERL-RTP)
     8:55     Opening of Technical Program - Session Chairman, A. McFarland (Texas A & M)
     9:00     First Paper - "Inertia Effects in Sampling Aerosols", C. N. Davies and M. B. Subari
             (U. of Essex, England)
     9:45     Break
    10:05     Second Paper - "Cyclone Sampler Performance", M. Lippmann (NYU) and
             T. L. Chan (Gen. Motors Res. Lab.)
    10:50     Third Paper - "Research on Dust Sampling and Measurement in Our Laboratory",
             K. linoya (Kyoto U., Japan)
    11:35     First Session Adjourns


   MONDAY EVENING

                     SESSION II: INSTRUMENTS AND TECHNIQUES FOR
                         PARTICLE-SIZE ANALYSIS (CONTINUED)


     7:30 pm  Call to Order - Session Chairman, D. Lundgren (U. of Florida)
     7:35     First Paper - "Sizing Submicron Particles with a Cascade Impactor", M. Pilat
             (U. of Washington)
     8:20     Second Paper - "Experience in Sampling  Urban Aerosols with the Sinclair  Diffusion
             Battery and Nucleus Counter", D. Sinclair and E. Knutson (Dept. of Energy)
     9:05     Third Paper - "Selecting Laboratory Instruments forfarticle Sizing", R. Draftz (IITRI)
     9:50     Second Session Adjourns
                                       128

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TUESDAY MORNING, MAY 16

                   SESSION III:  REAL-TIME MEASUREMENTS OF PARTICLE
                                  CONCENTRATION AND SIZE

   8:30 am   Call to Order - Session Chairman, W. Kuykendal (EPA/IERL-RTP)
   8:35      First Paper - "Long-Term Field Evaluation of Continuous Particulate Monitors",
             A. W. Gnyp, S. J, W. Price, C. C. St. Pierre, and D. S. Smith (U. of Windsor, Canada)
   9:20      Second Paper - "An  In-Situ Stack Fine Particle Size Spectrometer - A Discussion of
             Its Design  and Development", R. Knollenberg (Particle Meas. Systems)
  10:05      Break

  10:25      Third Paper - "Optical  Measurements of Particulate Size in Stationary Source Emissions",
             A. L. Wertheimer, W. H. Hart, and M. N. Trainer (Leeds & Northrup)
  11:10      Fourth Paper - "Studies of Relating Plume Appearance to Emission  Rate and Continuous
             Particulate Mass Emission Monitoring", K. T. Hood and H. S. Oglesby (NCASI)
  11:55      Third Session Adjourns


TUESDAY EVENING

                         SESSION  IV:  DATA REDUCTION, ACCURACY
                                   AND QUALITY CONTROL

   7:30 pm  Call  to Order  Session Chairman, T. T.  Mercer (U. of Rochester)
   7:35      First Paper - "A  Data Reduction System for Cascade Impactors", J. D.  McCain,
             G. I. Clinard, L.  G. Felix, and J. W. Johnson (Sou. Res. Inst.)
   8:20      Second Paper - "Aerosol Generation  and Calibration of Instruments", D. Y. H. Pui
             and  B. Y.  H. Liu (U. of Minnesota)
   9:05      Third Paper - "Collection Substrates  for Cascade Impactors", D. B. Harris (EPA),
             G. I. Clinard, L.  G. Felix, G. E. Lacey, and J. D. McCain (Sou. Res. Inst.)
   9:50      Fourth Session Adjourns


WEDNESDAY MORNING, MAY 17

                         SESSION V:  CONTROL DEVICE EVALUATION


   8:30 am  Call to Order  Session Chairman, G. B. Nichols (Sou.  Res. Inst.)
   8:35      First Paper - "Particle  Size Measurement for Evaluation of Wet Scrubbers",
              S. C. Yung, R. Chmielewski, G. Monahan, and  S. Calvert (APT, Inc.)
   9:20     Second Paper - "Evaluation  of Performance and Particle Size Dependent
             Efficiency of Baghouses", D. S. Ensor,  R. C. Hooper, G. Markowski (MRI),
             and  R. D. Carr (EPRI)
  10:05      Break
  10:25      Third Paper - "Evaluation of the Efficiency of  Electrostatic Precipitators",
             W. B. Smith, J. P. Gooch, J. D. McCain, and J. E. McCormack (Sou. Res.  Inst.)
  11:10      Fourth Paper  "Some Studies of Chemical Species in  Fly Ash", L. D.  Hulett,
             R. R. Turner, J.  M.  Dale, A. J. Weinberger, H. W. Dunn, C. Feldman, E. Ricci
             (Oak Ridge Nat.  Lab.) and J. 0. Thompson (Consultant)
  12:00 noon  Symposium Adjourns

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PRESENTATION TO FEDERAL REPUBLIC OF GERMANY

     Under this technical directive Mr. J,D. McCain of Southern
Research Institute wrote and presented a paper on manual par-
ticulate mass and size measurements at a workshop held in Ju-
lich, Federal Republic of Germany on March 16 and 17, 1978.
                              130

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PARTICULATE SIZING INSTRUMENT EVALUATION

     Criteria were developed for the evaluation of three real-
time particle sizing instruments.  The instruments are:

1.  a light scattering instrument—Particle Measuring Systems,
                                   Inc., Boulder, CO
2.  a light sensing virtual impactor—Meteorology Research, Inc.,
                                      Altadena, CA
3.  an acoustic  instrument—KLD Associates, Huntington Station, NY

     The suggested evaluation program is based on the operational
principle of each instrument.  The evaluation criteria based on
measurable parameters that are of greatest interest to EPA/IERL/
RTP have been developed  to allow comparisons of the three instru-
ments .

     The test plan is entitled "Particulate Sizing Instrument
Evaluation," Southern Research Institute Report Number SORI-EAS-
78-595, October  6, 1978.
                                131

-------
                           References


 1.   Cooper,  Douglas  W.  and John W.  Davis,  "Cascade impactors for
     aerosols:   Improved data analysis,"  Amer.  Ind. Hyg.  Assoc.,
     p.  79,  1972.

 2.   Cooper,  Douglas  W.  and Lloyd A.  Spielman,  "Data inversion
     using nonlinear  programming with physical  constraints:
     Aerosol  size  distribution measurement  by impactors,"
     Atmospheric Environment, Vol.  10, pp.  723-729, 1976.

 3.   Picknett,  R.  G., "A new method of determining aerosol size
     distributions from ministage sampler data," Aerosol Science,
     1972.

 4.   McCain,  J. D. ,  K.  M. Gushing,  and W. B.  Smith, "Methods
     for determining  particulate mass and size  properties:
     Laboratory and field measurements,"  J. APCA 2£(12):   1172-
     1176, December 1974.

  5. Rao, A.  K., "An  experimental study of  inertial impactors,"
     Ph.D. Dissertation, University of Minnesota, Minneapolis,
     Minnesota, 1975.

 6.   Dzubay,  T. G.,  L.  E. Hines and R. K. Stevens, "Particulate
     bounce errors in cascade impactors," Atmospheric Environment,
     Vol. 10, pp.  229-234, 1976.

 7.   Natusch, D. F.  S.  and J. R. Wallace, "Determination of air-
     borne particle size distributions:  Calculation of cross-
     sensitivity and  discreteness effects in cascade impaction,"
     Atmospheric Environment, Vol.  10, pp.  314-324, 1976.

 8.   Gushing, K. M.,  J.  D. McCain,  and W. B.  Smith, "Experimental
     Determination of sizing parameters and wall losses of five
     commercially  available cascade impactors," in Proceedings
     of the 69th Annual Meeting of the Air  Pollution Control
     Association,  Portland, Oregon,  1976, paper No. 76-374.

 9.   Lundgren,  D.  A.  (1967).  "An aerosol sampler for determina-
     tion of particle concentration as a  function of size and
     time," J.  APCA YT_,  pp. 225-229.

10.   Smith,  W.  B., K. M. Gushing, and G.  E. Lacey,  Andersen Filter
     Substrate Weight Loss Study.  EPA-650/2-75-022, U.S. Environ-
     mental Protection Agency, Research Triangle Park, N.C., 1975.
                                132

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11.  McCain, J. D., J. E. McCormack, and D. B. Harris.  Non-Ideal
     Behavior in Cascade Impactors.  70th Annual Meeting, APCA,
     Toronto, Ontario, Canada, 1977.  Paper 77-35.3.

12.  Felix, L. G., G. I. Clinard, G. E. Lacey, and J. D. McCain.
     Inertial Cascade Impactor Substrate Media for Flue Gas
     Sampling.  EPA-600/7-77-060, U.S. Environmental Protection
     Agency, Research Triangle Park, North Carolina, 1977, 89 pp.

13.  Lapple, C. E.  Processes Use Many Collector Types.  Chemical
     Engineering, 58:  144-151, 1951.

14.  Sproull, W. T.  Air Pollution  and Its Control.  Exposition
     Press, New York, 1970.

15.  Muschelknautz, E.  Design of Cyclone Separators in the
     Engineering Practice.  Staub-Reinhalt.  Luft, 30(5):  1, 1970,

16.  Leith, D. and W. Licht.  The Collection Efficiency of Cyclone
     Type  Particle Collectors-A New Theoretical Approach, A.I.Ch.E,
     Symposium Series, New York, New York, 1971, pp. 196-206.

17.  Chan, T., and M. Lippmann.  Particle Collection Efficiencies
     of Air Sampling Cyclones:  An  Empirical Theory.  Environ-
     mental Science and Technology, 11(4):  377-382, 1977.

18.  Ranz, W. D., and J. B. Wong.   Impaction of Dust and Smoke
     Particles, Ind. and Eng. Chem., 50, No. 4  (April, 1958).

19.  Marple, V. A.  A Fundamental Study of Inertial Impactors.
     Ph.D. Thesis, Mechanical Engineering Department, University
     of Minnesota, Minneapolis, Minnesota 55455, 1970.

20.  Willeke, K.  Performance of the Slotted Impactor.  Am. Ind.
     Hygiene Assoc. J., 683-691, September 1975.
                                  133

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            APPENDIX

A List of Reports Written under
     Contract No. 68-02-2131
            134

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Particulate Sizing Techniques For Control Device Evaluation:
Cascade Impactor Calibrations
Kenneth M. Gushing, George E. Lacey, Joseph D. McCain,
Wallace B. Smith
EPA-600/2-76-280, October 1976, NTIS  (PB 262 849/3BE)
(Original work supported by EPA Contract No. 68-02-0273.)

HP-65 Progammable Pocket Calculator Applied To Air Pollution
Measurement Studies:  Stationary Sources
James W. Ragland, Kenneth M. Gushing, Joseph D. McCain,
Wallace B. Smith
EPA-600/8-76-002, October 1976, NTIS(PB 264 284/1BE)

HP-25 Programmable Pocket Calculator Applied To Air Pollution
Measurement Studies:  Stationary Sources
James W. Ragland, Kenneth M. Gushing, Joseph D. McCain,
Wallace B. Smith
EPA-600/7-77-058, June  1977, NTIS(PB  269 666/4BE)

Procedures Manual for Electrostatic Precipitator Evaluation
Wallace B. Smith, Kenneth M. Gushing, Joseph D. McCain
EPA-600/7-77-059, June  1977, NTIS(PB  269 698/7BE)

Inertial Cascade Impactor Substrate Media For Flue Gas Sampling
Larry G. Felix, George  I. Clinard, George E. Lacey, Joseph D.
McCain
EPA-600/7-77-060, June  1977, NTIS(PB  276 583/2BE)

Development and Laboratory Evaluation of a Five-Stage Cyclone
System
Wallace B. Smith, Rufus Ray Wilson, Jr.
EPA-600/7-78-008, January 1978, NTIS(PB 279 084/8BE)

Particulate Sampling Support:  1977 Annual Report
Kenneth M. Gushing, William E. Farthing, Larry G. Felix,
Joseph D. McCain, Wallace B. Smith
EPA-600/7-78-009, January 1978, NTIS(PB 279 170/5BE)

A Computer-Based Cascade Impactor Data Reduction System
Jean W. Johnson, George I. Clinard, Larry G. Felix,
Joseph D. McCain
EPA-600/7-78-042, March 1978, NTIS  (PB 285 433)

Technical Mannual:  A Survey of Equipment and Methods for
Particulate Sampling in Industrial Process Streams
Wallace B. Smith, Paul  R. Cavanaugh,  Rufus Ray Wilson
EPA-600/7-78-043, March 1978, NTIS  (PB 282  501)


                              135

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Procedures Mannual For Fabric Filter Evaluation
Kenneth M. Gushing, Wallace B. Smith
EPA-600/7-78-113, June 1978, NTIS CPB 283 389)

An Electrostatic Precipitator Backup for Sampling Systems
P. Vann Bush, Wallace B. Smith
EPA-600/7-78-114, June 1978, NTIS (PB 283 660)

Evaluation of the PILLS-IV
William E. Farthing, Wallace B. Smith
EPA-600/7-78-130, July 1978, NTIS CPB 283 173)

A Data Reduction System for Cascade Impactors
Joseph D. McCain, George I. Clinard, Larry G. Felix, Jean W. Johnson
EPA-600/7-78-132a, July 1978

Design a Particle Sampling Test Facility
Norman L. Francis, Kenneth M. Gushing
SORI-EAS-78-560, September 22, 1978

Particulate Sizing Instrument Evaluation
William E. Farthing
SORI-EAS-78-595, October 6, 1978

Sampling Charged Particles With Cascade Impactors
William E. Farthing, David H. Hussey, Wallace B. Smith,
Rufus Ray Wilson, Jr.
EPA-600/7-79-027, January 1979

Guidelines For Particulate Sampling In Gaseous Effluents From
Industrial Processes
Rufus R. Wilson, Jr., Paul R. Cavanaugh, Kenneth Gushing,
William E. Farthing, Wallace B. Smith
EPA-600/7-79-028, January 1979

Proceeding:  Advances in Particle Sampling and Measurement
(Asheville, North Carolina, May, 1978)
Wallace B. Smith, Compiler
EPA-600/7-79-065, February 1979
                                 136

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                          .„     TECHNICAL REPORT DATA
                          (flease react Instructions on the reverse before completing)
 . REPORT NO.
 EPA-600/2-79-114
     2.
                                3. RECIPIENT'S ACCESSION-NO.
 . TITLE AND SUBTITLE
Particulate Sampling and Support: Final Report
                                5. REPORT DATE
                                 June 1979
                                                      6. PERFORMING ORGANIZATION CODE
 . AUTHOR(S)                        —^—	~

Kenneth M. Gushing and Wallace B. Smith
                                8. PERFORMING ORGANIZATION REPORT NO.
  'ERFORMING ORGANIZATION NAME AND ADDRESS
Southern Research Institute
2000 Ninth Avenue, South
Birmingham, Alabama  35205
                                10. PROGRAM ELEMENT NO.
                                INE623
                                11. CONTRACT/GRANT NO.
                                68-02-2131
12. SPONSORING AGENCY NAME AND ADDRESS
 EPA, Office of Research and Development
 Industrial Environmental Research Laboratory
 Research Triangle Park, NC 27711
                                13. TYPE OF REPORT AND.PERIOD COVERED
                                Final; 11/75 - 11/78	
                                14. SPONSORING AGENCY CODE
                                  EPA/600/13
15. SUPPLEMENTARY NOTES JERL-RTP project officer is D.  Bruce Harris, Mail Drop 62,
919/541-2557.
16. ABSTRACT The repOrj- summarizes results of research, development, and support
tasks performed during the 3-year period of the contract (11/75-11/78). The tasks
encompassed many aspects of particulate sampling and measurement in industrial
gaseous process and effluent streams.  Under this contract: cascade  impactors were
calibrated and evaluated; novel particle sampling cyclones were designed and eval-
uated; technical and procedures manuals were prepared for control device  evaluation
and particle sampling methods;  an  electrostatic precipitator backup was designed
for high flow rate systems; and  advanced concepts in monitoring particle mass and
size, using optical systems, were  evaluated. A number of smaller tasks, involving
lower levels of effort, are also  discussed.  The appendix lists technical documents
published under the contract.
17.
                             KEY WORDS AND DOCUMENT ANALYSIS
                 DESCRIPTORS
                                          b.lDENTIFIERS/OPEN ENDED TERMS
                                               COSATl Field/Group
 Pollution
 Dust
 Sampling
 Measurement
 Optical Measurement
 Industrial Processes
Impactors
Cyclone Separators
Electrostatic Pre-
 cipitators
Pollution Control
Stationary Sources
Particulate
Cascade Impactors
13B
11G
14B
                                             13H
131
07A
13. DISTRIBUTION STATEMENT
 Unlimited
                    19. SECURITY CLASS (ThisReport)
                    Unclassified	
                        21. NO. OF PAGES

                             147	
                    20 SECURITY CLASS (Thispage)
                     Unclassified
                                                                   22. PRICE
EPA Form 2220-1 (9-73)
                                           137

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