PB89-193320
Application Guide for Source PM10
Measurement with Constant Sampling Rate
Southern Research Inst., Birmingham, AL
Prepared for:
Environmental Protection Agency, Research Triangle Park, NC
May 89
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PB39-193320
EPA/600/3-88/057
May 1989
APPLICATION GUIDE FOR SOURCE PM1Q MEASUREMENT
WITH CONSTANT SAMPLING RATE
by
William E. Farthing
Sherry S. Dawes
Southern Research Institute.
Birmingham, Alabama 35255-5305
Contract No. 68-02-4442
Project Officer
Thomas E. Ward
Quality Assurance Division
Atmospheric Research and Exposure Assessment Laboratory
Office of Research and Development
Research Triangle Park, North Carolina 27711
ATMOSPHERIC RESEARCH AND EXPOSURE ASSESSMENT LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
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TECHNICAL REPORT DATA
(ftease read Instructions on the reverse before completing)
1. REPORT NO.
FPA/600/3-88/057
2.
3. RECIPIENT'S ACCESSION NO.
PB89 193320/AS
4. TITLE AND SUBTITLE
Application Guide for Source PM-10 Measurement with
Constant Sampling Rate
S. REPORT DATE
Mav 1989
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
William E. Farthing, S.S. Dawes
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Southern Research Institute
Birmingham, AL 35255
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-4442
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
Atmospheric Research and Exposure Assessment Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park. NC 27711
14. SPONSORING AGENCY CODE
EPA/600/09
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This manual presents a method, Constant Sampling Rate (CSR), which allows
determination of stationary source PM-10 emissions with hardware similar to that used
for Methods 5 or 17. The operating principle of the method is to extract a multipoint
sample so that errors due to spatial variation of particle size and anisokinetic
sampling are kept within predetermined limits. Current specifications were designed
to limit error due to spatial variations to 10%. -The maximum allowable error due to
anisokinetic sampling is +_ 20%; in essentially all sampling situations, cancellation
of sampling error will limit overall anisokinetic sampling error to much less than
this value.
This manual specifically addresses the use of the CSR methodology for determina-
tion of stationary source PM-10 emissions. Material presented in this manual includes
calibration of sampling train components, pretest setup calculations, sample
recovery, test data reduction, and routine equipment maintenance.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Croup
IB. DISTRIBUTION STATEMENT
Release to Public
IB. SECURITY CLASS (This Report/
Unclassified
21. NO. OF PAGES
7*7
20. SECURITY CLASS (Tills page I
Unclassified
22. PRICE
EPA F«m 2220-1 {«•». 4-77) PREVIOUS COITION i» OB»OLETE
1
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DISCLAIMER AND PEER REVIEW NOTICE
The information in this document has been funded wholly or in part by
the United States Environmental Protection Agency under contract 68-02-4442
to Southern Research Institute. It has been subjected to the Agency's peer
and administrative review, and it has been approved' for publication as an EPA
document. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
ii
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FOREWORD
Measurement and monitoring research efforts ..re designed to anticipate
environmental problems, to support regulatory actions by developing an
in-depth understanding of the nature and processes that impact health and the
ecology, to provide innovative means of monitoring compliance with regula-
tions, and to evaluate the effectiveness of health and environmental protec-
tion efforts through the monitoring of long-term trends. The Atmospheric
Research and Exposure Assessment Laboratory, Research Triangle Park, North
Carolina, has responsibility for: assessment of environmental monitoring
technology and systems for air, implementation of agency-wide quality assur-
ance programs for air pollution measurement systems, and supplying technical
support to other groups in the Agency including the Office of Air and
Radiation, the Office of Toxic Substances, and the Office of Solid Waste.
The environmental effects of PM10 particulate matter are of concern to
the Agency. Acceptable measurement methodology is critical for proper
assessment of the impact on the environment of these emissions from station-
ary sources. Preparation of a manual which specifies measurement procedures
is a key component for assuring reliable test data. This manual was prepared
to describe the maintenance and operating procedures for the Constant
Sampling Rate approach for measurement of PM1Q emissions from stationary
sources.
Gary J. Foley
Acting Director
Atmospheric Research and Exposure Assessment Laboratory
Research Triangle Park, North Carolina 27711
iii
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ABSTRACT
This manual presents a method, Constant Sampling Rate (CSR), which
allows determination of stationary source EM10 emissions with hardware
similar to that used for Methods 5 or 17. The operating principle of the
method is to extract a multipoint sample so that errors due to spatial varia-
tion of particle size and anisokinetic sampling are kept within predetermined
limits. If the range of duct velocities would cause the limit on anisokinet-
ic sampling error to be exceeded by a full traverse, the traverse is broken
into two or more subtraverses with different sampling nozzles. The number of
traverse points is selected to reduce errors due to spatial variation of
emissions to acceptable levels while allowing sufficient time for necessary
operator decisions between sampling points. In order to provide proper
averaging of emissions, the dwell time at each traverse point is proportional
to the local duct velocity. Current specifications were designed to limit
error due to spatial variations to 10%. The maximum allowable error due to
anisokinetic sampling is ±20% for 10 urn particles; in essentially all
sampling situations, cancellation of sampling error, and much smaller
contributions for particles smaller than 10 urn will limit overall anisoki-
netic sampling error to much less than this value.
The sampling device described in this manual is Cyclone I of the SRI/EPA
five-stage series cyclone. This device provides a 10-um size cut at a flow
rate of approximately 0.5 dscfm; the precise flow rate depends on local stack
conditions.
IV
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CONTENTS
Disclaimer • ii
Foreword iii
Abstract iv
Figures viii
Tables ix
Symbols x
1. Introduction 1
2. Operating Principles 3
2.1 Error due to anisokinetic sampling. ............ 3
2.1.1 Measurement of FM10 emission rate 4
2.1.2 Measurement of PM, Q fraction 6
2.2 Error due to spatial variation 6
2.3 Sampling hardware 7
2.3.1 Performance determination for PM^Q
samplers—cyclones 10
2.3.2 Performance specifications for PMj0
samplers—cyclones 15
2.3.3 Performance determination for PM1Q samplers—
cascade impactors . 16
2.3.4 Performance specifications for PM1Q samplers—
cascade impactors. . 18
2.3.5 SRI/EPA Cyclone 1 19
2.3.6 Sample nozzles ...... 21
3. Calibration 24
3.1 Flow metering system . 24
3.2 Pitot tube 24
3.3 Sampling nozzles 26
3.4 Thermocouples 26
3.5 Magnehelic gauges 26
3.6 Support equipment . 26
4. Presampling Activities 27
4.1 Equipment calibration and checks 27
4.2 Preparation of sampling reagents 28
5. Sampling Parameters 30
5.1 Preliminary measurements 31
5.1.1 Method 1 31
5.1.2 Methods 2, 3, and 4 31
5.2 Sample flow rate and nozzle selection for a single stage
cyclone sampler 31
5.2.1 Sample flow rate 31
5.2.2 Nozzle selection 33
V
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CONTENTS (Continued)
5.3 Sample flow rate anc" nozzle selection for cascade impactot
samplers 35
5.3.1 Sample flow rate 35
5.3.2 Nozzle selection 35
5.4 Sample orifice AH . . . 36
5.5 Dwell time 36
5.f Performing the calculations 37
6. Taking the Sample 42
6.1 Field assembly 42
6.2 Leak test 42
6.3 Pretest equipment warm-up 43
6.4 System start-up 43
6.5 Traversing 44
6.6 Shutdown orientation . 44
6.7 Data logging 44
7. Sample Retrieval 46
7.1 Recovery of the participate mass 46
7.2 Moisture determination 47
8. Post sampling Checks , 48
8.1 Equipment calibration checks 48
8.2 Sample analysis 48
9. Data Analysis. . .• 50
9.1 Velocity-weighted average 50
9.2 Dry gas meter volume 50
9.3 Volume of water vapor ..... 50
9.4 Percent moisture content 51
9.5 Stack gas molecular weight 51
9.6 Stack gas viscosity 51
9.7 Sample flow rate 51
9.8 Sampler Dgg . . 52
9.9 Stack gas velocity 52
9.10 Nozzle velocity 52
9.11 Nozzle AP limits 52
9.12 Percent isokinetic sampling 53
9.13 Concentration . . 53
9.14 Acceptance criteria 53
10. Maintenance 54
10.1 Vacuum system. ................. 54
10.2 Vacuum pump 54
10.3 Magnehelic differential pressure gauges 55
10.3.1 Zero adjustment 55
10.3.2 Calibration check 55
10.3.3 Recalibration 55
VI
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CONTENTS (Continued)
10.4 Dual manometer 56
10.5 Pitot tube 57
10.6 Nozzles 57
10.7 Thermocouples . . . 57
10.8 Sampling probe 57
10.8.1 Probe cleaning ...... 57
10.8.2 Probe heater check 58
10.9 Condensing system 58
11. Auditing Procedures 59
12. Recommended Standards for Establishing Traceability. ...... 60
References 61
Glossary of Symbols . 63
VII
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FIGURES
Number
2-1 Velocity ratio R versus duct velocity giving aspiration
coefficient of 1.2 and 0.8 for particles with aerodynamic
diameter of 10 um at various gas viscosities
2-2 PM.Q particulate sampling train with out-of-stack filter
(analogous to Method 5) 8
2-3 PMin particulate sampling train with in-stack filter
(analogous to Method 17) 9
2-4 Calibration system for heated aerosols 11
2-5 Efficiency envelope for PM1Q sampler (cyclones) 16
2-6 Efficiency envelope for PM1Q sampler (cascade impactors) .... 19
2-7 Cyclone I dimensions 20
2-8 PM1Q nozzle design . . 22
2-9 Optimum inside cone angle, 8, for various nozzle inlet diameters 23
5-1 Minimum number of traverse points for CSR traverse 32
5-2 CSR worksheet I - sample flow rate and orifice AH calculations . 38
5-3 CSR worksheet II - nozzle selection 39
5-4 CSR worksheet III - dwell time calculations 40
6-1 CSR field data sheet 45
viii
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L
TABLES
Number Pags
2-1 Particle sizes and nominal gas velocities for efficiency
performance tests of cyclones 15
\
2-2 Performance specifications for source PM,. samplers—cyclones. . 15
2-3 CSR nozzle diameters and velocity limits 21
2-4 PM10 nozzle geometries 23
IX
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SYMBOLS
A Aspiration coefficient (measured concentration/actual
concentration)
AJ Total cross-sectional area of the jet{s) of the PM10 st-.age
AJJ Cross-sectional area of sampling nozzle, ft2
B (2 + 0.617/RJK
B Water fraction of stack gas
C Cunningham slip factor
C Concentration of particulate, ag/dNra3
C'm Concentration of particulate matter, gr/dscf
C_ Pitot tube coefficient for the CSR probe
C^ Pitot tube coefficient for Method 2 probe
d Nozzle diameter
d. Diameter or width of one jet of the PM, » stage
d^ Diameter of nozzle n, in.
D Particle aerodynamic diameter, yra
D50 Cyclone cut diameter, ym
IT Velocity-weighted average of generic data terra, D
D- Average value of generic data term, D, for each nozzle size
D,, Stack differential pressure, in. H20
^stack *
^ Collection efficiency for PM10 stage n
Es Average Egara
Esam Sampler-only collection efficiency
Et Average Etot
Efcot Total (nozzle and sampler) collection efficiency
f10 PM10 fraction
fc Fraction C02
f Fraction O2
I Percent isokinetic sampling
K Particle Stokes number with respect to the nozzle, iv/d
85.48 ft/s (lb/mole-*R)
Dry molecular weight of stack gas, Ib/mole
Met Mass of dye collected in the sampler exit tube
Mf^ Mass of dye collected in the backup filter
Mjj Q Molecular weight of water, 18 Ib/roole
M^2 Mass of dye collected on PM10 stage n
Mn Mass of dye collected on all surfaces downstream of PM10 stage n
M Mass of dye collected in the sampling nozzle
Mass of collected particulate (either per stage or total), mg
sam Mass of dye collected in the sampler body
MW Wet molecular weight of stack gas, Ib/mole
n Number of component changes
P Ambient pressure, in. Hg
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ST
5S
Sr
R
Re
R
u
S
Stk
Stk50
M
ST
u
v
V.
rain
max
M
MS
WS
Absolute stack pressure, in. Hg
Absolute pressure at standard conditions, 29.92 in. Hg
Flow rate through «-he sampler (sampler conditions) , acfra
Sample flow rate (standard conditions), ft3/rain
Ratio of stream velocity to nozzle velocity
Reynolds number
Ideal gas constant, 21.83 in. Hg-ft3/mole-*R
Standard deviation
Stokes number, fv/d, dimensionless
Stokes number giving 50% collection efficiency
Dwell time at the first traverse point, min
Run time for each nozzle size
Absolute gas meter temperature, *R
Absolute stack gas temperature, *R
Absolute temperature at standard conditions, 528 *R
Nozzle velocity, ft/s
Stream velocity, ft/s
Total volume of liquid collected in impingers or condenser/silica
gel, mL
Minimum allowable stack velocity to be sampled with a given nozzle
diameter, ft/s
Maximum allowable stack velocity to be sampled with a given nozzle
diameter, ft/s
Volume of gas sample flow through the dry gas meter (meter
conditions), ft3
Volume of gas sample flow through the dry gas meter (standard
conditions), ft3
Stack gas velocity, ft/s
Volume of water vapor in the gas sample (standard conditions), ft3
XI
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v Gas meter calibration constant
AH Orifice pressure drop, in. H20
AH Orifice pressure differential for a flow rate of 0.75 cfm at
standard conditions, in. H2O
AP Velocity pressure head, in. H2O
&?! The velocity AP at the first traverse point, in. H2O
(/AT) Average square root of velocity APs, used to calculate average
avg
stack velocity
AP Maximum allowable velocity pressure to be sampled with a given
a ax
nozzle diameter, in. H2O
AP . Minimum allowable velocity pressure to be sampled with a given
Bin
nozzle diameter, in.
AP The velocity AP at traverse point n, in. H,0
n *
AP Velocity pressure drop of standard pi tot tube, in. H. O
9 Total run time, rain
M Gas viscosity, micropoise
j Density of water, 1 g/mL
Ho O
a Gecsetric standard deviation of lognormal distribution
9
T Particle relaxation time CD2/18u
* Outside taper or cone half-angle for a sampling nozzle
$ Inside taper or cone half-angle for a sampling nozzle
0.5 Stk
*50 °'5 Stk50
XI 1
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SECTION•1
INTRODUCTION
To ensure a representative sample of particulate matter is obtained from
a flowing gas stream, three key factors must be considered. First, the
length of the sampling period must be adequate to formulate an appropriate
temporal average of stream conditions. Second, the location and number of
sampling points must be chosen so that a spatial average of emissions across
the sampling plane is obtained. Finally, sampling must be performed
isokinetically so that the sample is not biased with respect to particle
size. These conditions are addressed in the EPA methods for measuring total
particulate emissions (Methods 5 and 17) by specifying sampling periods which
take into account process cycles, traversing techniques rather than single
point sampling, and adjustments in sample flow rate (i.e., nozzle velocity)
to match local stream velocity at each point of the traverse so that
isokinetic sampling is maintained.
However, a size-specific method, such as one for measuring particulate
matter of aerodynamic diameter *10 Urn (PM10), must combine the considerations
of obtaining a representative sample with the need to segregate the sample
into two or more size fractions. Inertial sizing devices such as cascade
impactors and sampling cyclones must be operated at a constant flow rate to
maintain constant size cuts. For a fixed nozzle size, this precludes any
adjustment in nozzle velocity to maintain isokinetic sampling. Without the
use of new sampling hardware such as exhaust gas recycle (EGR), a PM10
sampling method must then become a compromise between the conflicting
requirements of inertial particle sizing and representative sampling.
This manual presents a method. Constant Sampling Rate (CSR), which
allows determination of PM10 emissions from stationary sources with hardware
similar to that used for Methods 5 or 17. The operating principle of the
method is to extract a multipoint sample-so that errors due to spatial
variation of particle size and anisokinetic sampling are kept within
predetermined limits. Current specifications were designed to limit error
due to spatial variations to 10%. The maximum allowable error due to
anisokinetic sampling is ±20% for 10 urn particles; in essentially all
sampling situations, cancellation of sampling error and much smaller
contributions for particles smaller than 10 um will limit overall
anisokinetic sampling error to much less than this value. This method has
been identified in some previous EPA documents as the Simulated Method 5
(SIM-5) or Constant Flow Rate (CFR) method.
Fundamental to a method of this type is the device used to perform the
particle sizing required for PMio collection. The device used in development
of .this method was Cyclone I of the SRI/EPA five-stage series cyclone
1
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(Smith et al., 1979). For this reason, in some portions of this manual, such
as Section 7, Sample Retrieval, instructions are given specifically for this
device. Another single stage cyclone could be used if its performance has
been adequately characterized as specified in Section 2.
This does not mean the use of other devices, such as cascade impactors,
should be discouraged. In recognition of the fact that cascade impactors may
often be used as the PM.Q device, key sections of this manual address the use
of these devices. Specific instructions concerning performance determination
and specification for cascade impactors are given in Section 2. In Section
5, instructions for choosing the sample flow rate and nozzle(s) are given.
Once these parameters are fixed, sampling procedures are the same as with a
single-stage sampler. This manual does not address sample retrieval, stage
size cutpoint determination, or interpolation of data for multiple stages to
determine PM10. Acceptance criteria for size outpoints, once they are
determined, are given in Section 9. It is beyond the scope of this manual to
provide complete operating instructions for impactors. Numerous manuals are
available which provide information in this area. Unfortunately, these
manuals also, reflect a varying degree of completeness. The impactor manual
chosen for use in conjunction with this CSR manual should include discussions
of how anomalous behavior, such as particle bounce, may be avoided, the
effects of jet-to-plate spacing, and the variation of size cut with Reynolds
number. A recommended manual is the "Procedures Manual for the Recommended
ARB Particle Size Distribution Method (Cascade Impactors)," by McCain et al.
(1986).
This manual is organized so that the user is guided step-by-step through
initial use of the method in a field situation. Section 2 describes the
basic principles from which CSR was developed and the specifications for the
critical sampling hardware. Section 3 describes the procedures by which
various components of a CSR system may be calibrated. Activities which are
required or recommended prior to field use of the method are outlined in
Section 4. Section 5 describes the calculations required to establish the
sampling parameters prior to sampling, and Section 6 outlines the steps to
follow during operation of a sampling system. Retrieval of the collected
sample is described in Section 7. Sections 8 and 9 describe required
postsampling checks and analysis of the field data. Routine maintenance of a
CSR system is discussed in Section 10. Auditing procedures and recommended
standards are described in Sections 11 and 12.
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SECTION 2
OPERATING PRINCIPLES
Many different approaches to resolving the dilemma posed by the
conflicting requirements of fixed flow rate and representative sampling may
be suggested. One approach used frequently in the past for control device
evaluation involved operating the sampler at a sufficient number of points in
the sampling plane such that the dominant error source would be anisokinetic
sampling bias. Because the concentrations of the fine particles, which were
the particles of greatest interest, could be measured correctly without
sampling isokinetically, this mode of operation was acceptable for the
purpose. However, sampling in this manner did not ensure any level of
accuracy was to be obtained in the measurement of overall size distributions.
Another approach was to operate the sampler at near-isokinetic conditions at
a single traverse point. In this case, the errors due to spatial variation
in the particle size distribution would be large unless a full traverse of
the sampling plane was synthesized from a number of these single-point
measurements. This would be very costly in terms of on-site sampling time.
In developing the CSR strategy, a compromise between the options
described above was sought. Several specific objectives shaped the details
of the method. First, the technique was designed to minimize changes in
equipment from that used for Methods 5 or 17. Second, the details of the
traversing strategy were selected to limit errors from spatial variation and
anisokinetic sampling to the level of more intrinsic errors (such as fluctua-
tions in source emissions or basic measurement inaccuracy). Finally,
measurements would be made to provide an average representative of emission
rates rather than concentration.
2.1 ERROR DUE TO ANISOKINETIC SAMPLING
To obtain a sample which is unbiased with respect to particle size, one
must sample isokinetically. That is, the gas velocity of the sample stream
entering the sampling nozzle must match the local gas velocity in the duct
from which the sample is being withdrawn. If the gas velocity in the nozzle
is greater than the local duct velocity, the flux of large particles through
the nozzle cross-section will be less than that for the free stream; large
particles are those which do not follow flow streamlines because of their
inertia. As a result, the collected mass of large particles will be selec-
tively depleted. Conversely, if the gas velocity in the nozzle is lower than
the local duct velocity, the flux of large particles through the nozzle
cross-section will be greater than that of the free stream. The collected
mass of large particles in this instance will be selectively enriched. The
resulting concentration of very small particles in the sample remains
unchanged from that in the duct in either case. The resulting concentration
of very large particles in the sample approaches the ratio of the duct
velocity to the nozzle velocity.
3
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For any given particle diameter, the anisokinetic sampling error may be
expressed as the aspiration coefficient, which is defined as the ratio of
measured concentration to actual concentration. Belyaev and Levin (1974)
developed a semi-empirical relationship for aspiration coefficient, A, in
terms of the particle Stokes number, K, and the ratio of stream velocity, v,
to nozzle velocity, u.
A = 1 + (R - 1) B * 1 (2-1)
where R » velocity ratio v/u
B »• (2 + 0.617/R)K
K = particle Stokes number with respect to the nozzle, TV/<3n
T = particle relaxation time CD^/ISu, seconds
C * Cunningham slip factor
D * particle aerodynamic diameter
u a gas viscosity, poise
d * nozzle diameter
n
Equation 2-1 shows that, for given stack conditions and particle size,
limiting the ani&okinetic sampling error becomes a question of limiting the
velocity ratio, R. In other words, for a given limit on error due to aniso-
kinetic sampling, maximum and minimum values of R (\iax and R^^ will yield
results within the stated limits. It may also be noted from equation 2-1
that B is proportional to particle diameter squared. This indicates that
anisokinetic sampling error decreases with decreasing particle size. In
other words, when sampling for EMjo emissions, the velocity ratio, R, could
be outside the 0.9 to 1.1 range specified for total emissions in Methods 5
and 17 and still retain equivalent accuracy.
The choice of the limits on anisokinetic sampling error for CSR is
important. An overly generous range could produce data with an excessive
amount of error. At the other extreme, small limits would restrict the
velocity ratio to the point that most sites would require multiple nozzle
sizes for a complete traverse, which would increase the on-site sampling
effort.
2.1.1 Measurement of PM1Q Emission Rate
For the purposes of PM1(., limits of ±20% on error due to anisokinetic
sampling were chosen to specify the limits on the velocity ratios, R_in and
Rmax. Solving equation 2-1 for R as a function of stream velocity, v,
viscosity, u, sample flow rate, Q, and particles with aerodynamic diameter of
10 urn, the series of curves shown in Figure 2-1 are defined. The upper
curves give Rmax and correspond to the upper limit on A (1.2). The lower
curves give RJnin and correspond to the lower limit on A (0.8). As can be
seen from the figure, the limits on R are broad at the smaller stream
velocities and approach limits of ±20% at high stream velocities.
Actual sampling error for most sources will be less than the ±20% limit
foe two reasons. First, point-by-point R values will usually be something
less than the limits, Rmjn and Rfflaxr and cancellation of errors will occur
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0.5
3 4 56789 10
VELOCITY, m/sec
20
30 40 50 60
Figure 2-1. Velocity ratio R, duct velocity/nozzle velocity, versus duct velocity giving aspiration
coefficient of 1.2 (upper curves) and 0.8 (lower curves) for particles with aerodynamic
diameter of 10 n/n and gas viscosities ranging from 160 to 280 x 1Q-6 poise. Sampling
error of 10 fim particles is less than ± 20% for R-values between an upper and a lower
curve.
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because R-1 values will be negative at some points and positive at others.
Second, the curves shown in Figure 2-1 *ere determined by assuming a raono-
disperse sample of 10-Ura particles. In actuality, the FM10 sample is
composed of particles with aerodynamic diameters less than 10 vim.
2.1.2 Measurement of PH,n Fraction
Limits on the velocity ratio, R, for measurement of the PM, Q fraction of
total emissions are determined in a slightly different manner than those for
the PM.g emission rate. This is necessary because of two important differ-
ences between the two parameters. First, because anisokinetic sampling
introduces both positive and negative errors to the two size classifications
of interest (particles less than 10 urn in diameter and particles greater than
10 um in diameter), there is partial cancellation of the error when the ratio
is taken to calculate the PM10 fraction. Second, because there is no upper
limit on particle size for the portion greater than 10 urn, the ratio B/(B+1)
in equation 2-1 must be assumed to be unity for this size fraction when
determining the limits on sampling error.
For a particular source, the limit on percent error in measurement of
PMjg fraction (f10) is approximately the quantity
(R - 1)(1 - f1Q) x 100
where R is the minimum or maximum value of velocity ratio experienced during
the sampling run. Limits for acceptable values of R are determined by
setting the error to ±10%. The limits then become
*min - 1 - T-T~ -* "max " ' + TT^ I2'2'
Determination of these limits requires an estimate of the PM1Q fraction, so
it may be necessary to repeat some runs because of poor estimates of the
limits as a result of incorrect values for f.Q in conjunction with substan-
tial variation of velocity across the sample plane.
2. 2 ERROR DUB TO SPATIAL VARIATION
The goal of a traversing strategy should be to reduce error due to
spatial variation so that it is not the dominant source of error but is
comparable to or less than other sources of error. Extensive analyses have
been made of the uncertainty in measurements of total particulate emission
caused by spatial variation in process streams. The analysis presented by
Shigehara (1982) suggests that 8 to 12 traverse points provide a large reduc-
tion in error from one point, whereas additional points provide little addi-
tional decrease.
In general, the PM1Q fraction is expected to be less stratified than
total particulate emissions. The lower inertia of the m10 fraction would
cause less deviation from gas flow in bends and faster damping from turbulent
diffusion once stratification is produced. On the basis of available FM10
profiles. Farthing (1983) concluded that Shigehara's data may be used as a
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conservative estimate of error due to spatial variation in PMjn measurements.
Using the 8 to 12 traverse points specified in the CSR protocol is expected
to reduce this type of error to less than ±10%.
2.3 SAMPLING HARDWARE
As stated previously, one of the objectives during the development of
the CSR technique was to make use of existing sampling equipment. Therefore,
the hardware changes required to operate a CSR sampling system have been kept
to a minimum. Like a standard total particulate sampling train, a CSR system
nay be operated with an out-of-stack filter (analogous to Method 5) or an
in-stack filter (analogous to Method 17). Block diagrams of the systems are
shown in Figures 2-2 and 2-3, respectively. If the CSR train is operated
with an in-stack filter, a heated probe is not required, but steps should be
taken to prevent condensed moisture from running back into the sampling
device and contaminating the sample.
As can be seen from Figures 2-2 and 2-3, the apparent differences
between CSR and standard total emissions hardware are confined to the front
end of the probe. There are some less obvious differences, however. The
sampling flow rate at which a CSR train is operated is set by the requirement
that the sample be segregated into two or more specified size fractions. In
addition to stack conditions, this flow rate is dependent on the geometry and
characteristics of the sampling device. In other words, different sampling
devices may have significantly different sampling flow rates. In the case of
SRI/EPA Cyclone I, described later in this section, the flow rate which
provides a 10-vm cut is approximately 0.50 dscfm. This is considerably lower
than the Method 5 or Method 17 nominal flow rate of 0.75 dscfm. To control
this flow rate with a reasonable degree of accuracy, a smaller orifice than
that typically used for Method 5 (0.180 in.) will be required. Experience
has shown 0.130 in. is a practical diameter for the sample orifice when a CSR
train is operated with a SRI/EPA Cyclone I. However, this may not be an
appropriate size for a different sampling device for the reasons given
previously. To minimize uncertainty in choosing the sample orifice size or
to prepare for operating the sampling train with a number of sampling
devices, a set of orifices should be acquired with the following diameters:
0.180 in./ 0.130 in., and 0.093 in.
As Figures 2-2 and 2-3 show, the primary difference between CSR and
Methods 5 or 17 hardware is the PMjq sampling device. Although a number of
particle sizing devices may be considered for use as a PM,, device, practical
considerations eliminate several of the choices. For the purposes of this
method, the only single-stage device which should be considered is an
in-stack cyclone. Although a single stage of a cascade impactor may provide
the appropriate size segregation, problems such as particle bounce and
reentrainment keep this from being an acceptable choice. The multistage
device recommended for use with this method is a Cascade impactor. Although
a series cyclone such as the SRI/EPA five-stage series cyclone provides
particle sizing similar to that of a cascade impactor, the mass loading
necessary for adequate sample retrieval would require unacceptably long run
times for most outlet concentrations.
-------
HEATED PROBE
SIZE
SEPARATOR
IMPINGER TRAIN OPTIONAL:
MAY BE REPLACED BY AN
EQUIVALENT CONDENSER
HEATED
AREA FILTER HOLDER
THERMOMETER
ORIFICE
THERMOMETERS BYPASS
VALVE
CHECK
VALVE
IMPINGERS IN ICE BATH
O<>r*-l>O-
MAIN VACUUM LINE
VALVE
MANOMETER DRY TEST METER AIRTIGHT PUMP
4111-C4SB
Figure 2-2. PM-JQ paniculate sampling train with out-of-stack filter (analogous to Method 5).
l_
-------
IMPINGER TRAIN OPTIONAL:
MAY BE REPLACED BY AN
EQUIVALENT CONDENSER
PM10
SIZE
SEPARATOR
CHECK
VALVE
IMPINQERS IN ICE BATH
THERMOMETERS BYPASS '
^ _ VALVE ' /^\ VACUUM
ORIFICE O Q T T ^ GAUGE
'
MAIfl VACUUM LINE
VALVE
MANOMETER DRY TEST METER AIRTIGHT PUMP
UI1-445A
Figure 2-3. PM JQ paniculate sampling train with in-stack filter (analogous to Method 17).
-------
Before any particle sizing device is used as a PM10 sampler, it must be
shown to meet some specific performance requirements. The procedures by
which this itay be done are discussed in the following sections for both
single-stage and multistage devices (cyclones and cascade impactors, respec-
tively) . The specific performance requirements for each of these devices are
also given.
2.3.1 Performance Determination for PM,n Samplers—Cyclones
To determine that a given cyclone meets the requirements for use as a
PMig device, the performance determination procedures outlined in the follow-
ing text must be performed. The objectives of these procedures are twofold:
(1) to calibrate the cyclone (i.e., establish the relationship between
collection efficiency, flow rate, gas viscosity, and gas density for the
given device) and (2) to determine that cyclone performance satisfies the
performance specifications with the sampling nozzles used in practice.
2.3.1.1 Particle Generation—
The particle generating system used for the performance determination of
the sampler must be capable of producing solid, raonodisperse dye particles
with mass median aerodynamic diameters ranging from 5 to 20 urn. The geomet-
ric standard deviation (a ) for each particle size should not exceed 1.1.
Furthermore, the proportion of raultiplets and satellites should not exceed
10% by mass.
The size of the solid dye particles delivered to the test section of the
wind tunnel should be established by using the operating parameters of the
particle generating system. This should be verified during the tests by
microscopic examination of samples of the particles collected on a membrane
filter. The precision of the particle size verification technique should be
0.5 um or better, and the particle size determined in this manner should not
differ by more than 10% from that established by the system operating parame-
ters.
The monodispersity of the particles should be verified for each test by
either microscopic inspection of particles collected on filters or monitoring
techniques such as an optical particle counter followed by a multichannel
pulse height analyzer: It is preferable that verification of acceptable
particle size distribution be performed on an integrated.sample obtained
during the sampling period of each test. As an alternative, samples obtained
before and after each test may be used to verify the size distribution.
To determine cyclone behavior as a function of yas conditions, the
system must be operated at a range of temperatures. The dye particles must
withstand temperatures from 22 *C (70 *F) to 200 *C (400 *F) without signifi-
cant change in size, density, or spectral properties in solution (associated
with measurement of collected particulate mass). Ammonium fluorescein
(available from a number of sources) has been shown to meet these require-
ments for temperatures up to S50 *F and Pontamine Fast Turquoise 8GLP (avail-
able from B.I. DuPont de Nemours and Company) has been shown to meet them up
to 400 "F (Smith et al., 1979). However, the thermal integrity of each dye
batch should be verified.
10
-------
The requirements of the apparatus for heating the monodisperse dye
aerosol axe illustrated in Figure 2-4. A pump with an orifice or other flow
aeter is used to obtain the test flow rate through the cyclone. The combina-
tion of absolute filter/bleed valve allows excess aerosol to escape or addi-
tional air to enter as needed. The aerosol stream from the generator passes
through a copper tube heated to attain the test temperature. The heat trans-
fer rate and uniformity of heating should be sufficient for the aerosol to
attair. the t.*st temperature but should not cause the temperature of any
interior surfaces to rise above the teroerature used for verifying the
integrity of the dye. The inlet tube to the cyclone must have th»» same
inside diameter as the inlet diameter of the cyclone. This tube must be
cleaned between runs and blanks performed to check for possible effects of
reentrainment of particles which accumulate on its interior. The sample port
is necessary to collect and examine heated -particles for correct size, color,
and shape for each measurement run.
AEROSOL STREAM
CROM VIBRATIMG
ORIFICE AEROSOL
GENERATOR
ABSOLUTE FILTER
OVEN
KEPT AT
AEROSOL TEMPERATURE
U
il
MEAT |
EXCHANGER
THERMOCOUPLE
SAMPLING
PORT
MERCURY WATER
MANOMETER MANOMETER
4181 92
figure 2-4. Calibration system for heated aerosols.
11
-------
2.3.1.2 Wind Tunnel--
A portion of the collection efficiency tests must be performed under
isokinetic sampiirvg conditions in a wind tunnel or similar apparatus so that
the effect of the sampling nozzle on the cyclone performance may be deter-
mined. This apparatus must be capable of establishing and maintaining
(within 10%) velocities ranging from 7 to 25 ra/s.
The velocity of the wind tunnel gas stream in the vicinity of the
sampling nozzle should be measured by using an appropriate technique capable
of a precision of 5% or better and of a spatial resolution of 1 cm or less
(e.g., hot wire aneraometry or miniature pitot tubes). The velocity should be
constant within 10% over the inlet area of the largest sample nozzle to be
used with the PM,0 sampler. If the sampler obstructs more than 10% of the
wind tunnel cross-sectional area, the velocity uniformity must be demon-
strated by velocity measurements with the sampler in position and operating.
Poc each efficiency test, the gas stream velocity should be determined
at the beginning of each test and maintained within 10% of the set value by
using a suitable monitoring technique with precision better than 5%.
2.3.1.3 Cyclone Calibration —
To achieve the first objective of the performance determination (estab-
lish the relationship between collection efficiency, flow rate, and gas
conditions) the following procedures should be followed.
The operator should establish operation of the particle generator and
verify particle size microscopically. If monodispersity is to be verified by
measurements at the beginning and end of the measurement run rather than by
an integrated sample, these measurements should be performed at this time.
Plow should be initiated through the cyclone at the test value after stable,
correct operation of the generator is established. The operator should
sample long enough to obtain ±5% precision on total collected mass as deter-
mined by precision and sensitivity of the measuring technique. Immediately
after completion of sampling, the size of the aerosol particles should be
verified microscopically.
The sampled particulate mass is determined by a suitable technique
(fluorittetry or absorption spectrophotometry for ammonium fluorescein). The
mass collected in the nozzle, PMJO sampler body, PMJO sampler exit tube, and
backup filter (*noz> MSiB' Met' Mfil' resP«ctively) ls determined separately.
2ach separate surface must be rinsed with an adequate amount of an appro-
priate solvent to dissolve the collected dye particles, and care must be
taken not to contaminate the rinses with dye from other surfaces. Sufficient
solvent must be added to each rinse until the rinse volume is suitable for
Measurement or calculation. The mass of dye in the rinses is to be deter-
mined from the spectroscopic measurement by using appropriate blank and
standard solutions for reference and quality control.
12
-------
The total (nozzle and sampler) and sampler-only collection efficiencies (Etot
and Egam) may be calculated from the following equations:
•tot " 100S x (Mnoz + Msam>/ <2'3'
Esam " 100% x Msam/ <2"*>
At least two replicates of the above steps should be performed.
The average efficiency should be calculated and recorded as
n n
I Etot(i) I Esam(i)
where Efc fc(i) an^ Esam^ represent individual Efc fc and E values and n
equals the number of replicates.
The standard deviation (S) for the replicate measurements should be calcu-
lated and recorded as
0.5
.T E2(i) - ( I E(i))2/n'
n - 1
where E(i) represents Etot(i) and Egam(i)
(2-6)
For n « 2, S » [E(1) - E(2)]//7. If the value of S for Etofc exceeds 10% of
Et, the test run must be repeated.
The size cut, D^Q, of the cyclone is established by either of two sets
of measurements. In one set, operating conditions are adjusted to obtain a
collection efficiency, Eg, of SO ±5% for a single particle size. Three
replicate runs should be performed with the actual particle size for each run
within ±5% of the desired value. In the other set, E is measured with at
least three particle sizes at the same operating conditions, and linear
interpolation in log-probability space is used to determine the 05 0- In the
latter set, the measured Eg valu ----- - •-- " " ----- "" " """ "
values both below and above 50%'.
latter set, the measured E_ values must be between 20 and 80% and include
3
2.3.1.4 PM1Q Plow Rate-
To determine the empirical relationship between FN^Q flow rate and gas
conditions, the D^0 determination described above must be performed for at
least three temperatures. The DJQ'S must be between 5 and 15 urn and measured
at temperatures within 60 *C (108 *F) of the temperature at which the cyclone
will be used. In addition, one of the measured DSQ'S must be 10 ± 0.5 urn.
13
-------
Linear regression analysis is used to determine the relationship between
the dinensionless parameters *SQ (= 0.5 Stkcg) and Re, where Stk50 is the
Stokes number giving 50% collection and Re is the Reynolds number of the gas
entering the cylcone.
and
where Q » gas flow rate through the cyclone at the inlet conditions
u » gas viscosity
d * diameter of the cyclone inlet
p * gas density at the cyclone inlet
Vfith the substitution of D5Q =• 10 urn into the resulting relationship, the
flow rate for PM10 measurements is predicted as a function of gas conditions.
2.3.1.5 Determination of Cyclone/Nozzle Collection Efficiency —
Because the cyclone and sampling nozzles are used as a unit in actual
sampling situations, it is necessary to establish that the nozzles do not
perturb the particle sizing characteristics of the cyclone as determined by
the calibration procedures discussed previously. To do this, collection
efficiency tests should be performed for the cyclone/nozzle unit by using the
particle diameters and gas velocities shown in Table 2-1. For the appro-
priate PH10 sampler flow rate, the operator should determine the nozzle size
appropriate for isokinetic sampling in each of the three velocity ranges
shown in the table. If more than one nozzle is suitable for a range, the
larger nozzle may be chosen.
After the three nozzle sizes have been determined, the first airstream
velocity to be tested in the wind tunnel should be established and verified
as described previously. The particle generating system should then be
started and the particle size distribution verified. The particle size, as
determined by the system operating conditions, must be within the tolerances
specified in the table. The operator should begin sampling by establishing
the flow rate required for a lO-ym D in the cyclone.
At the completion of the runs, the total and sampler-only collection
efficiencies (Etot and Bg—B) should be determined from equations 2-3 and 2-4.
Pot each of the three gas stream velocities tested, the average E^ and Bg
should be plotted as functions of particle size (0) on semi log paper. Smooth
curves should be drawn through all sizes used. The 050 for Ea should be
defined as the diameter at which the Eg curve crosses 50% efficiency.
14
-------
TAPLE 2-1. PARTICLE SIZES AND NOMINAL GAS VELOCITIES FOR
EFFICIENCY PERFORMANCE TESTS OF CYCLONES
Target uas velocity (a/a;
Particle Size (um)a 7±1.0 1511.5 25 ±2.5
5 ±
7 ±
10 ±
14 ±
0.5
0.5
0.5
1.0
20 ± 1.0
aMass median aerodynamic diameter.
Number of test points (minimum of two replicates for each
combination of gas velocity and particle size) : 30.
2.3.2 Performance Specifications for PM Samplers - - Cyclones
The performance specifications for a PM1Q cyclone are shown in
Table 2-2. To be acceptable for use, the %0 for the sampler (determined
from the Eg curve as described previously) must be 10 ± 1 urn. In addition,
all data points used to determine the Et curves for each of the gas stream
velocities tested must fall within the banded region shown in Figure 2-5.
The portion of the acceptance envelope corresponding to large particles is
bounded by a vertical line at 12 yra, a horizontal line at 90% efficiency, and
a log normal function (oblique line) with geometric standard deviation (o ) of
1.7 and 50% efficiency at 12 urn. The boundary at small particle sizes has a
vertical line at 8 urn and horizontal lines and lognormal functions which vary
between three ranges of gas stream velocity. These horizongal lines are at
10, 20, and 30% efficiency, respectively, with increasing gas velocity. At
the lowest range of velocity the lognormal function has a of 1.7 and 50%
efficiency at 8 urn. For the two higher velocity ranges, the lognormal func-
tions have 55% efficiency at 8 urn and values of a of 2 and 2.9 respectively,
with increasing gas velocity.
TABLE 2-2. PERFORMANCE SPECIFICATIONS FOR SOURCE PM10 SAMPLERS—CYCLONES
Parameter Units Specification
1. Collection Efficiency % Such that collection efficiency
falls within envelope specified
in Figure 2-5
2. Sampler 50% cut point urn 10 ± 1 urn aerodynamic diameter
«>50>
15
-------
95
8 "
0 80
2
0 7°
I 60
Z 5°
? 40
0
0
30
20
10
5
17 < v < 27 m/s
9 < v < 17 m/s
v < 9 m/s
I
I III
2 4 6 8 10 20 40
AEROOWWflC OWOER. fn „„.,,
2-5. Efficiency envelope for PM JQ sampler (cyclones).
2.3.3 Performance Determination for
Samplers— Cascade Impactors
Like those foe cyclones, the performance determination procedures for
cascade impactors have two objectives: (1) to calibrate the cascade impactor
(i.e., determine the ?tk5Q for each of the three PH1Q stages) and (2) deter-
mine the relationship between Stk50 and nozzle inlet diameter for the first
stage.
The particle generating system and wind tunnel used to perform these
tests should be the same as those described previously for cyclones. There
fore, further description of this test equipment will not be given here.
2.3.3.1 Impactor Configuration for Performance Tests —
It is expected, but not necessary, that the complete impactor hardware
assembly will be used in each of the sampling runs of these calibration and
performance determinations. ?or these measurements, the first FMio stage
16
-------
must be calibrated with the nozzles sampling isokinetically in the wind
tunnel. The first P^ Q stage consists of the collection substrate and all
upstream surfaces, up to and including the nozzle. This includes all preced-
ing impactor stages which are not designated as PM1Q stages.
The second and third PM1Q stages consist of each respective collection
substrate and all upstream surfaces up to (but excluding) the collection
substrate of the preceding PM10 stage. This includes intervening impactor
stages, which are not designated as PM10 stages. These stages must be cali-
brated with the collection substrate (impaction surface) of the preceding
PMig stage in place so that gas flow patterns existing in field operc*-ion
will be simulated.
Each of the PM^ stages should be calibrated with the type of collection
substrate, viscid material (such as grease) or glass fiber used in FM10
measurements. It should be noted that most materials used as substrates at
elevated temperatures are not viscid at normal laboratory conditions. The
substrate material used for calibrations should minimize particle bounce yet
be viscous enough to withstand erosion or deformation by the impactor jets
and not interfere with the procedure for measuring the collected particulate
mass.
2.3.3.2 Impactor Calibration—
Calibration is begun by sampling monodisperse aerosols of sizes within
±67% of the cut size utilized in field PMjQ measurements. Procedures
analogous to those described previously for cyclones ace used. However,
potential interference of substrate material (grease or glass fiber)
entrained in the rinsing process must be eliminated.
The particulate mass collected by PM. Q stage n, N , and particulate mass
on all surfaces downstream of stage n, Mn , should be determined. Particu-
late mass on the upstream side of a jet plate should be included with the
substrate downstream of it. However, agglomerates of particles that obvious-
ly were removed or reentrained from an upstream surface should be included
with the preceding substrate. Collection efficiency for stage n, E , is
calculated as
Bn - 100% x V^n * V* {2"9)
Equation 2-10 demonstrates the calculation of th*> diraensionless parameter *
(=0.5 Stk, where Stk is the Stokes number) for each measurement.
0.5 Stk - D2 - 2
(2-10)
where 0 * particle diameter
Q » gas flow rate through the PM10 stage at inlet conditions
u » gas viscosity
Aj » total cross-sectional area of the jet(s) of the PMic stage
dj • diameter or width of one jet of the PMio stage
17
-------
should be measured while varying Y to empirically determine ¥50* the
value for 50% collection efficiency. Particle bounce can cause efficiency to
decrease at high, values of ¥ and thus pass through 50% at multiple values of
Y. Therefore, the calibration data should clearly indicate the value of
¥50 for minimum particle bounce. Impactor efficiency versus ¥ with minimal
particle bounce is characterized by a monotonically increasing function with
constant or increasing slope as V increases.
2.3.3.3 Determination of *50 versus Nozzle Diameter—'
The *50 of the first PM10 stage can potentially decrease with decreasing
nozzle size. Therefore, this stage must be calibrated with the nozzle
sampling isokinetically in a wind tunnel or similar test apparatus. These
nozzles should have diameters ranging from the smallest to the largest likely
to be used in FM10 measurements. Calibrations should be performed with
enough nozzle sizes to provide a measured value within ±25% of any nozzle
size used in M10 measurements, thus providing a set of f5Q-values for the
first PMjg stage, needed for determining particle size cut in PMJO
measurements. The ^50 value for any nozzle size is determined by
interpolation between calibration values.
In addition to measuring collection efficiency versus Hf for determining
?5Q, calibration measurements should be performed for the first stage at
values of ? low enough that the efficiency of stage one, EL , is between 20
and 30%. This data point and all other data (efficiency and ¥) available for
any nozzle diameter are relevant to the performance specification in the next
section.
2.3.4 Performance Specifications for PM^ Samplers—Cascade Impactors
As can be seen from Figure 2-6, the acceptance envelope for a candidate
MIO impactor stage is analogous to that for cyclones with the exception that
the abscissa has been changed from aerodynamic particle diameter to values of
square root of ^/*§o« To determine if a given impactor stage meets the
performance criteria, efficiency versus the square root of I/Ten should be
plotted. For the first stage, the data plotted should be those obtained with
each of the nozzle diameters tested. All data must fall within the banded
region of Figure 2-6 if the stage is to be accepted.
18
-------
2
z
0
95
90
80
n 70
60
50
40
30
0 **
0 20
10
5
17 < v < 27 m/s
9 < v < 17 m/8
v < 9 m/a
0.1
0.2
0.4 0.6 OJ 1
(211-11
Figure 2-6. Efficiency envelope for PM JQ sampler (cascade impactor).
2.3.5 SRI/EPA Cyclone I
One sampling device known to meet the performance specifications given
previously is the commercially available version of Cyclone I, the first
stage of the SRI/EPA five-stage series cyclone. The outer dimensions and
physical appearance of the cyclone may vary, depending on the specific
commercial source. The critical inner dimensions, however, are standardized
to the original design parameters, as can be seen in Figure 2-7. Laboratory
calibrations (Farthing and Williamson, 1985) have shown Cyclone I produces a
10-um E^0 at a flow rate of approximately 0.5 dscfra; the precise flow rate
will depend on local stack conditions.
19
-------
CYCLONE I DIMENSIONS
BOTTOM EXIT
cup
DIMENSIONS
/em ± 0.02 \
\in.*0.
-------
2.3.6 Sample Nozzles
The anisokinetic error limits for CSR are bro-
nozzles for a single traverse will seldom be necea^ enough that multiple
sources, the temporal or spatial variation of streAy. However, at some
"to require more than one nozzle. The frequency of: velocity is sufficient
size is not sufficient for the complete traverse i^*sts in which one nozzle
of nozzle sizes available. Small increments for t^ Delated to the increments
the likelihood that a nozzle size will be availably nozzle sizes increase
near the mean stream velocity. In this case, |R - to give a nozzle velocity
possible value; moreover, the likelihood is then 1% I is at its lowest
will exceed the limits for the chosen nozzle. Thi^ * that rtream velocities
increments simplifies the raeas 'ements and improve^ ^3 ing snaller nozzle
^he accuracy.
The set of nozzle diameters found to provide ^
increments is shown in Table 2-3. The nozzle velo^uff icient number of
diameter for the Cyclone I PM1Q flow rate at the q(^y corresponding to each
the limits on stream velocity for acceptable use of *n stack conditions and
shown. The minimum and maximum velocity variation^ *ach nozzle are also
when using each nozzle are given in the last two dv*hich may be encountered
full range of nozzle diameters shown in the table wWs of the table. The
most instances. In other words, sampling situation U not be required in
tered which require the smallest or largest nozzle '"ill seldom be uncoun-
table. ^ameters shown in the
TABLE 2-3. CSR NOZZLE DIAMETERS (in.) AND VE
tTY LIMITS (ft/s)a
Nozzle
Diameter
0. 136
0.150
0.164
0.180
0.197
0.215
0.233
0.264
0.300
0.342
0.390
*Por dry
79
For gas
Nozzle
Velocity
100.9
82.9
69.4
57.6
48.1
40.4
34.4
26.8
20.7
16.0
12.3
Min.
Stream Min.
vel. vel.
(A-0.8) ratio
76.4
61.5
50.1
40.0
31.6
24.4
18.1
13.4
10.4
8.0
6.1
gas composition (%
°2 CO2
4 16
conditions
CO
1
(*R, in.
0.76
0.74
0.72
0.70
0.66
0.60
0.53
0.50
0.50
0.50
0.50
volume) and
H,0
0 06
H.O, and in
"V
Stream
vel. Max.
(A»1.2) vel.
-
102.8
86.8
73.0
61.8
52.9
46.0
37.3
30.5
23.9
18.4
.23
.24
.25
.27
.29
.31
.34
.39
.47
.50
.50
Action:
. Hg):
Velocity
Variation
* t f
0.15
0.15
0.17
0.19
0.21
0.25
0.31
0.35
0.39
0.40
0.40
•• \
0.24
0.25
0.26
0.29
0.31
0.35
0.41
0.45
0.49
0.50
0.50
760
-2
21
-------
Because of the impact the nozzle geometry may have on performance of the
j. device, specification of nozzle inlet diameters is not sufficient to
guarantee acceptability. Numerous laboratory tests with SRI/EPA Cyclone I
have resulted in the development of the nozzle design shown in the
Figure 2-8. The critical geometric parameters shown in the figure are speci-
fied in Table 2-4 for the range of nozzle diameters discussed previously.
The inside taper or cone angle, *, for each of the nozzle diameters was
determined from Figure 2-9. This figure gives the optimum cone angle/ as
determined from laboratory tests, for any given nozzle inlet diameter. The
outside taper, *, should be 15* and the inlets sharp-edged so that the
criteria of Belyaev and Levin (1972) for negligible particle bounce from the
inlet will be met. The length of straight section at the nozzle inlet, I,
should not exceed 0.05 in. Longer inlet sections may result in the develop-
ment of velocity profiles in the nozzle which may seriously perturb perfor-
mance of the EM10 device or contribute to excessive particle losses in the
nozzle. The total length, L, for the nozzle diameters (dn) given in
Table 2-4 range from 2.653 to 1.45 in. The minimum length of 1.45 in. was
chosen to position the nozzle inlet a sufficient distance away from the body
of the PM,0 sampler so that the flowstreara would not be disrupted. For
nozzles with larger inlet diameters, a straight section at the nozzle outlet
(after the expansion from the inlet diameter to the outlet dimension,
0.50 in.) will be necessary to meet this minimum length requirement.
Figure 2-8. PM10 nozzle design. L = total length of nozzle; dn = nozzle inlet diameter;
C = straight inlet length; 0 = inside cone angle; = outside taper angle.
22
-------
TABLE 2-4. PM10 NOZZLE GEOMETRIES
Nozzle Cone
Diameter, dfl Angle,.
(inches) (degrees)
0.136 4
0.150 4
0.164 5
0.180 6
0.197 6
0.215 6
0.233 6
0.264 5
0.300 4
0.342 4
0.390 3
i
£ 7 -
-e-
•
O
5s
b
y ,
G O -
— o _
2 •
UJ
z
04
1 •
O
n 1 1
Outside
Taper , $
(degrees)
15
15
15
15
15
15
15
15
15
15
15
i
1
!
Straight Inlet
Length, i
(inches)
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
<0.05
i i
t i
Total Length,
L
(inches)
2.653±0.05
2.553±0.05
.970±0.05
.572±0.05
.491±0.05
.45 ±0.05
.45 ±0.05
.45 ±0.05
1.48 ±0.05
1.45 ±0.05
1.45 ±0.05
0.1 0.2 0.3 0.4
NOZZLE INLET DIAMETER (in.)
0.5
Figure 2-9. Optimum inside cone angle, , for various nozzle inlet diameters.
23
-------
SECTION 3
CALIBRATION
As for Method 5 or Method 17, calibration of specific components of a
CSR sampling system is required. It is recommended a notebook or other
record be kept of all calibration data pertinent to each system. This record
should contain the complete calibration history of each device requiring such
service (i.e.r flow metering devices, pitot tubes, nozzles, thermocouples,
and Magnehelic* gauges). A separate record may be desirable for support
equipment, such as balances and field barometers, which are not directly
connected with che system.
3.1 PLOW METERING SYSTEM
The best calibration of a flow metering device is achieved when the
calibration data are restricted to the range of expected use. The defined
Method 5 flow rate of 0.75 dscfm provides a finite range of flow rates over
which the flow metering system should be calibrated. However, the PM10 flow
rate is dependent on the characteristics of the sampler used and cannot be
easily defined as a single value. This makes defining a calibration range
for the flow metering devices difficult at best. For the purposes of this
manual, the W10 flow rate at typical meter box conditions is assumed to be
0.50 acfm. It is up to the reader to determine the applicability of this
flow rate to his particular system.
The flow metering devices of a CSR system (dry gas meter and sample
orifice) should undergo a stringent laboratory calibration before field use.
In addition to this initial acceptance testing, the calibration should be
checked after each test series. This calibration check procedure ensures
that the calibration parameters assigned to the flow metering devices are
still valid without requiring the level of effort of the initial calibration.
Should the results of the calibration check fall outside acceptable limits,
the flow metering device in question should be recalibrated according to the
initial calibration procedure.
Before any c .ibration, a leak check of the metering system should be
performed. This should be done for both the vacuum (negative pressure) and
positive pressure portions of the train as prescribed in Method 5 (U.S. EPA,
1977).
A calibrated wet test meter or any other such calibration standard
should be used to calibrate the flow metering system. The outlet of the
calibration standard should be connected to the sample inlet of the control
console. Before starting the calibration, the operator should run the system
vacuum pump for 15 min. with the orifice meter pressure drop (AH) set at
approximately 0.5 in. H^O to allow the pump to warm up and to wet the
24
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interior surface of the wet test meter. The calibration should be performed
as required in EPA Reference Method 5 for a range of orifice AH settings
(0.5, 1.0, 1.5, 2.0, 3.0, and 4.0 in. H20). The minimum wet test meter
volume for each run should be 5.0 ft3, except for the two lowest flow rates,
for which a volume of 3.O ft3 is acceptable. The data should be recorded as
requested in Method 5.
A calibration check should be performed on all of the flow metering
devices after each field test series. The posttest calibration check shoul'.
consist of three calibration runs at a single orifice setting. This orifice
setting should be representative of the orifice settings used during the
field test. The run procedure should be the same as described for the
initial calibration.
If the dry gas meter calibration factor, Y, deviates by less than 5%
from the initial calibration factor, then the calibration constant assigned
to the meter is still valid. If the posttest calibration check yields a
calibration factor outside this limit, the gas meter should be recalibrated
by using the initial calibration procedure.
The averaae AH recorded during the calibration check should be compared
with that obtained from the calibration equation for the device. To calcu-
late the AH from the calibration equation, the wet test meter flow rate
corrected for temperature and pressure should be used. If the recorded
pressure drop varies from the calculated value by more than 10%, the orifice
should be recalibrated.
If the dry gas meter requires recalibration, for the purposes of data
reduction, use whichever coefficient (initial or recalibrated) yields the
lower gas meter volume.
3.2 PITOT TUBS
The construction, configuration, and calibration specifications outlined
in EPA Reference Method 2 (U.S. EPA, 1977) should be applied to the CSR pitot
tube. The pitot tube should be located at the side of the sampling nozzle
furthest from the sampling device axis. To check the pitot tube for leaks,
one end of the tube should be plugged and a positive pressure applied at the
opposite end. If the tube will not maintain pressure, a soap solution can be
used tc identify the location of any leaks. If the CSR pitot tube requires
calibration, the velocity pressure drop, .*P, should be measured with a
standard pitot tube and the S-type CSR pitot tube at the same point within a
cross-section of a straight run of ductwork for a desired range of gas
velocities. The CSR pitot tube should be calibrated as used; that is, the
complete sampler assembly should be used in pitot tube calibration determina-
tions. The CSR pitot tube should be calibrated twice, as recommended in
Method 2, reversing the direction of the legs during the second calibration.
For each velocity, a pitot tube coefficient is determined as
A P 1/2
C? - °-99
25
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where Cp =» S-type pitot tube coefficient, dimensionless
0.99 = Cp value for standard pitot tube, dimensionless
"?ST = velocity pressure drop of standard pitot tube, inches of water
-?CSR a velocity pressure drop of CSR S-type pitot tube, inches of
water
The average value of C_ for each direction over the range of velocities used
should be calculated.
3.3 SAMPLING NOZZLES
A micrometer should be used to measure the inside diameter of the nozzle
to the nearest 0.001 in. Three separate measurements should be made/ each
based on a different diameter, and the average of the measurements should be
calculated. The largest deviation from the average should not exceed
0.004 in. If the variation is more than 0.004 in., the nozzle should be
reshaped and recalibrated.
3.4 THERMOCOUPLES
The thermocouples used to measure the various temperatures within the
sanpling train should be checked to ensure they are properly calibrated
before they are installed in the system. A two-point calibration check using
an ice bath and a boiling water bath should be performed as outlined in EPA
Reference Method 2. If any individual thermocouple does not produce a read-
ing within ±1.5% of the absolute reference temperature, it should be replaced
with another thermocouple of the same type. If all thermocouples show a
bias, the readout should be adjusted or recalibrated according to the
manufacturer's procedure.
3.5 MAGHEHELIC* GAUGES
The calibration of the Magnehelic* differential pressure gauges should
be checked prior to field use and periodically thereafter to prevent invali-
dation of test data. Before calibration, the Magnehelic* gauge with no
applied pressure should be adjusted to read zero using the external
zero-adjust screw. To perform a calibration check, AP values, as read from
the Magnehelic* gauge, should be compared with those from an inclined
•anoaeter at a minimum of three points. The 4P values lead from the
Magnehelic* gauge should not deviate fro* the inclined manometer readings by
sore than 5% at any point.
3.6 SOPPORT EQUIPMENT
The field barometer should be adjusted initially and before each test
series to agree with a standard (a raercury-in-glass barometer or the pressure
reported by a nearby National Weather Service station) to t 0.1 in. Hg.
The calibration of all balances to be used during a test series should
be checked initially with class-S weights. Triple beam balances should be
within to.5 g of the standard. Analytical balances should agree to ±2 mg of
the standard. Balances which fail to meet these criteria should be adjusted
or returned to the manufacturer.
26
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SECTION 4
PRESAMPLING ACTIVITIES
Preparation of the CSR sampling system for field use requires much the
same effort as preparation for Method 5 or Method 17 sampling (U.S. EPA,
1977). Some type of pretest calibration or operation check is necessary for
most components of the system. This is also true of supporting equipment
such as analytical balances. Sampling reagents also require preparation
prior to field use. In several cases, the presampling activities described
below are similar to or the same a& those required for Method 5.
4.1 EQUIPMENT CALIBRATION AND CHECKS
All sampling nozzles should be inspected for damage and repaired where
necessary. The nozzles should be cleaned with tap water, deionized water,
and finally acetone. The inside diameter of each nozzle should be measured
to the nearest 0.001 in. as described in Section 3 of this manual. The knife
edge of the nozzle should be protected during shipment by serum caps or
similar covers.
The PM1(, sampler and filter holder should be ultrasonically cleaned with
tap water and rinsed with deionized water. After a final rinse with acetone,
the sampler assembly should be allowed to air dry. An adequate supply of
Viton or silicone rubber O-rings should be available for replacement of worn
0-rings in these devices.
The openings of the pitot tube should be visually inspected for damage
such as dents or nicks. A check should also be made for proper alignment.
The two legs of the pitot should be in a straight line so that the opening of
one leg is directed 180* from the other. If damage or misalignment is
evident, the pitot tube should be repaired or replaced. If repairs are made,
the pitot tube should be recalibration, as described in Section 3.
The lines of the sampling probe, including the pitot lines, should be
cleaned before field use. The lines should be cleaned internally by rinsing,
first with tap water, then deionized water, and then acetone. The lines
should be rinsed a final time with acetone and allowed to air dry. If a
heated probe is used, the heating system should be checked for proper opera-
tion. (If problems are encountered, see Section 10 of this manual for
troubleshooting guidelines.)
The water dropout system (condenser and drying column) should be checked
for leaks. The condenser should be cleaned with deionized water and rinsed
with acetone. The condenser should be inverted to ensure total drainage and
allowed to air dry.
27
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The system flow metering devices (dry gas meter and orifice) should have
appropriate calibration factors assigned to them. A pretest calibration
check, performed according to the procedure outlined for posttest calibration
checks in Section 3, is recommended to ensure the calibrations are still
valid. Although pretest calibration checks of the flow metering devices are
not required and do not take the place of the posttest checks, they are
useful for detecting problems prior to field use. Such a pretest calibration
check is strongly recommended if the system has not been used for some time.
It is recommended, but not required, that the calibration of the
Magnehelic* pressure differential gauges be checked prior to field sampling.
As with the flow metering system, this is strongly suggested if the system
has not been used for an extended period of time.
All system temperature sensors (thermocouples, temperature gauges, etc.)
should be checked against a mercury-in-glass thermometer at ambient tempera-
ture.
Finally, it is recommended that a leak check of the complete system be
performed before it is shipped. The system should be assembled from tne
probe (it is not necessary to include the nozzle or PM1Q sampler) to the
control console. The probe should be capped and the system leak-checked at
15 in. Bg vacuum. Leak rates in excess of 0.02 cfm should be corrected.
Bach leg of the pitot tube should be leak-checked, including the umbilical
lines and the differential pressure gauge.
4.2 PREPARATION OF SAMPLING REAGENTS
Osed silica gel should be regenerated by drying at 350 *F for 2 h. New
silica gel may be used as received. Several 200- to 300-g portions may be
weighed in airtight containers to the nearest 0.5 g. The total weight for
each container should be recorded. As an alternative, the silica gel may be
weighed in the drying column at the test site.
Quartz fiber is the recommended filter material because it is more
resistant to chemical reactions when exposed to stack gases. Filters should
be desiccated and weighed as required for EPA Reference Method 5. To prevent
the loss of filter cake, it is recommended that aluminum foil envelopes be
made to enclose the filter. If used, these envelopes should be desiccated
and weighed with the filter.
Aljainoa foil envelopes can also be used to collect the PM Q cyclone
catch. These foil envelopes should be uniquely identified, desiccated, and
weighed in the same manner as the filters.
Aluminum weighing dishes or small glass beakers may be used to collect
and evaporate the rinses from the sampling device. These containers should
be cleaned thoroughly, labeled, desiccated, and weighed prior to use. If the.
sampling train is operated in a Method 5 configuration, a larger glass beaker
or similar container will be needed for probe rinses.
28
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Acetone for sample recovery should be reagent grade with less than
0.001% residue. Acetone blank determinations to ensure residue levels are
acceptable may be made before field use or as part of sample recovery.
29
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SECTION 5
SAMPLING PARAMETERS
The sampling parameters which must be dealt with in the CSR procedure
are the same as those in EPA Methods 5 or 17 (U.S. EPA, 1977), with the
addition of those for particulate mass for each size fraction. However, the
two types of procedures are substantially different in terms of control of
sampling parameters. In the CSR procedure, sample flow rate is determined by
the requirement that the size separation device maintain fixed size cut(s) at
or near 10 um (aerodynamic). For a single-stage cyclone sampler, this flow
rate is determined uniquely by the gas composition and temperature of the
process stream. For a cascade impactor, the gas composition and temperature
determine a range of permitted flow rates from which to choose before
sampling is initiated.
Because flow rate cannot be adjusted during a sampling run to match
nozzle velocity with the velocity of the gas stream, thus eliminating errors
associated with anisokinetic sampling, the nozzle(s) must be carefully
selected. First the sample flow rate is determined, then the range of stream
velocities at which sampling is to be performed determines the nozzle(s) to
be used. For each nozzle diameter, there is a range of stream velocities
which correspond to a permissible level of anisokinetic sampling error.
Usually, the stream velocity in a sampling plane will be uniform enough that
one nozzle size will be acceptable for the entire range of stream velocities.
However, for process streams with wide variation of velocity, it may be
necessary to use more than one nozzle for a complete traverse of the sample
plane.
A third difference between CSR and other methods for particulate emis-
sions involves the sample duration, or dwell time, at each traverse point.
In Method 5 or 17, the dwell time is tha same for all traverse points. A
velocity-weighted average of the measured concentration, or emission rate, is
obtained when the sample flow rate is adjusted proportionally to the local
stack velocity, as described previously. Because the sample flow rate cannot
be adjusted when the CSR method is used, a velocity-weighted concentration is
obtained by adjusting the dwell time at each point to be proportional to the
local stack velocity.
These differences between the methods manifest themselves in the setup
calculations required before a sampling run. This section presents the
governing equations and describes the calculations required to determine the
CSR sampling parameters. In some cases these calculations are much the same
as those required for Methods 5 or 17. References to the appropriate EPA
method will be cited in these situations. Only those equations and calcula-
tions which are unique to CSR will be discussed in detail here.
30
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5. 1 PRELIMINARY MEASUREMENTS
5.1.1 Method 1
Before the appropriate sampling parameters can be calculated, some
preliminary determinations must be made. First, the number of traverse
points required for CSR should be determined from Figure 5-1. The procedures
and requirements for this determination are the same as Method 1. For
rectangular stacks, the equivalent duct diameter should be calculated as in
Method 1 (U.S. EPA, 1977). The traverse points should be located within the
duct as described in Method 1.
5.1.2 Methods 2, 3, and 4
When the number of traverse points and their locations within the duct
have been decided upon, the stack temperature and velocity at each of these
points should be determined by Method 2 (U.S. EPA, 1977).
The concentration of the primary stack gas constituents (i.e., oxygen,
carbon dioxide, nitrogen, carbon monoxide, and water vapor) may be determined
from Method 3 (U.S. EPA, 1977) and Method 4 (U.S. EPA, 1977) data. With this
information, the gas dry and wet molecular weights may be determined from the
following equations:
Md - 32 (f0) + 44 (fc) +28(1 - f Q - fc) (5-1)
(5-2)
It may be necessary to perform additional testing according to standard
methods in instances where the stack gas composition is influenced by gases
other than those listed above. For example, when gases from a high-sulfur
source are sampled, Method 6 (U.S. EPA, 1977) testing should be performed to
determine the percentage of SO2 present in the process gas, and this percent
SO2 should be taken into account when determining the dry molecular weight.
5.2 SAMPLE FLOW RATE AND NOZZLE SELECTION FOR A SINGLE-STAGE CYCLONE SAMPLER
5.2.1 Sample Flow Rate
If a single-stage size separation sampler is to be used, the sample flow
rate must be that which provides a 10-um size cut. This flow rate will be
determined by the gas composition and temperature of the process gas. The
relationship between flow rate and gas parameters specific to the sampling
device must be determined by calibration measurements (described in
Section 2) prior to field use. For SRI/EPA Cyclone I, this relationship
takes the form
M p -0. 29<»9
Q_ - 0.002837 (_ !L1) u. (5-3)
Ts
31
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DUCT DIAMETERS UPSTREAM FROM FLOW DISTURBANCE (DISTANCE A)
0.5 1.0 1.5 2.0 2.
SO
Z 40
O
AVERSE
w
O
oc
o
c
IU
| 20
3
Z
1
2
z 10
2™*
0
I I . I
» HIGHER NUMBER IS
FOR RECTANGULAR STACKS
OR DUCTS
—
J
t
B
•
-
—
I
1
7
DISTURBANCE
MEASUREMEN
I SITE
DISTURBANCE
~^M«wn««
T
—
12
"™"
I I III
8 OR 9" ~
I
3 4 5 67 8 9
DUCT DIAMETERS DOWNSTREAM FROM FLOW DISTURBANCE (DISTANCE B)
Figure 5- J. Minimum number of traverse points for CSR traverse.
10
57«5-€J
32
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The viscosity of the flue gas can be determined by the equation
(Williamson et al., 1983)
.. 5* (* 4- f* T * P T 2 * I"1 B A <"• F
u » G! + c2Ts + c3Ts^ + c^ws + C5fo
where u is in micropoise, T in "C, and
Cj - 160.62
C2 » 0.42952
C3 = 1.0483 x
G, - -74.143
Cg » 53.147
or for T in *R
Cx » 51.05
Cj - 0.207
C3 » 3.24 x 10-5
Q, » -74.143
C5 - 53.147
This equation fits data (with a standard error of 0.98 micropoise) for
combustion gas of arbitrary composition in the range 0-350 *C, 0-70%
moisture. This equation was generated from large "data banks" of viscosities
calculated by the more rigorous algorithm of Wilke (1950).
5.2.2 Nozzle Selection
After the sample flow rate has been determined, the corresponding nozzle
velocity (u) for any given nozzle may be determined from the following equa-
tion:
u = —i—- Qs (5-5)
wan
For each nozzle velocity, a range of stack velocities, v ^ to v , for
which the anisokinetic sampling errors are within acceptable limits must then
be determined. As discussed in Section 2, this range of stream velocities is
governed by the semi-empirical relationship developed by Belyaev and Levin
(1974)
A - 1 + (R - 1) .T4-T- (2-D
where A * measured concentration/actual concentration
R » isokinetic ratio, v/u
B - (2 + 0.617/R)K
K » particle Stokes number with respect to the nozzle, tv/d
T « particle relaxation time CD2/T8u, seconds
C - Cunningham slip factor
D » particle aerodynamic diameter
u a gas viscosity, poise
dn * nozzle diameter
33
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Defining vrain as tne stack velocity at which A equals 0.8 and vraax the stack
velocity at which A equals 1.2, we obtain equations for vmin and vmax such
that
, /0.2603 Qa1/2y,
vmin ' u [0-2457 + / 0.3072 --f ] (5-6)
r /0.2603 Qa1/2y
u [0.4457 + / 0.5690 + --f
n J / i
vmax " u [°-4457 + ^ 0.5690 + 3^2 J (5-7)
where the terms in brackets are equivalent to the velocity ratios', ^-m^n and
Rmax, respectively, and have additional limits of 1.0 ± 0.5 if more
restrictive.
Although the vmin and vmax for a given nozzle are useful, the local
stack velocity is actually measured as velocity pressure differentials during
both Method 2 and CSR traverses. Therefore, it is ioore practical to convert
vmi« an^ vma» *° tne cor responding pressure differentials by using the
mxn nicUm
following equations:
AP . » 1.3686 x 10-* -S-^ (-r^5-) (5-8)
.
s
(5-9)
where C_ is the pitot coefficient of the CSR sampling probe, and all other
variables are as defined previously.
Finally, given the most recent Method 2 data for the sampling plane and
the AP limits for a given set of nozzles, the nozzle or nozzles required to
perform the sample traverse may be determined. In instances where the pitot
coefficients of the Method 2 probe and the CSR probe are different, the
Method 2 data should be converted to equivalent values for the CSR pitot.
This is accomplished by using the following equation:
C
AP(CSR) = AP(Method 2) ( )2 (5-10)
S1
The AP limits for the chosen nozzle should bracket the measured stream
values. If more than one nozzle is acceptable, the one giving the greatest
symmetry should be selected. If the expected pitot AP for one or more points
is near a limit for the chosen nozzle, it may be outside the limits at the
time of the run due to temporal variations of the process.
34-
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5.3 SAMPLE PLOW RATE AND NOZZLE SELECTION FOR CASCADE IMPACTOR SAMPLERS
Several cascade impactocs ace available which can be used for PM1Q
measurement. The relationships between particle size cut, sample flow rate/
gas coaposition, temperature, and nozzle diameter (for the first PM.. stage)
must have been determined by calibration measurements (described in Section
2) before field sampling. Procedures for operating these devices,
calculating particle size cut for each stage, and analysis of the results to
obtain cumulative mass concentration as a function of particle size are
described by McCain et al. (1986).
5.3.1 Sample Flow Rate
The multiple stages of a cascade impactor provide the ability to inter-
polate, thus permitting determination of PMjg without the requirement that a
stage have a 10-yra size cut. This flexibility in flow rate permits minimiza-
tion of error due to anisokinetic sampling by selection of a nozzle and flow
rate corresponding to the average stream velocity, v, of the process stream.
The sample flow rate is selected from the set, Q_, determined by
Qn • v *dn2/4 (5-11)
where Qn * flow rate for nozzle n at the average stream velocity
dn = diameter of nozzle n.
One of this set of flow rates is selected subject to the additional criteria
below: .
e The impactor must include one stage cut at or greater than 10 urn and
two succeeding size cuts less than 10 urn.
o The separation between these successive size cuts must be no more
than a factor of 2 and no less than a factor of 1.5.
o The product of jet velocity and size cut for each impactor stage with
cut above 2 urn should satisfy the criteria given by McCain et al.
(1986) for the particulate collection substrates utilized to limit
particle bounce.
5.3.2 Nozzle Selection
Calculation of minimum and maximum stream velocities, vm^n and vmax, for
a given nozzle depends upon the desired accuracy for particles greater than
10 urn. If the >10-um particulate fraction is of little concern, the calcula-
tion of vmin and vmax given for single-stage cyclones (equations 5-6 and 5-7)
and similarly for APmin and APm?x (equations 5-8 and 5-9) can be used. The
errors in cumulative concentration versus particle size, due to anisokinetic
sampling, will be limited to no more than ±20% at 10 yra, decreasing sharply
35
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with particle size. The corresponding error for M10 will be much less,
depending upon the size distribution of the <10-ura particles.
If accurate measurement of particle sizes greater than 10 urn is sought,
then the more restrictive limits of McCain et al. (1986), which require
nozzle velocity to be within ±20% of the stream velocity at each traverse
point, are recommended. In this case, the error limit of cumulative percent
data for arbitrary size distribution is given by the percent deviation of
nozzle velocity from stream velocity.
5.4 SAMPLE ORIFICE AH
After the sample flow rate and nozzle size have been determined, the
orifice pressure drop, AH, corresponding to this sample flow rate may then be
calculated from the following equation:
2S(1 * Bws)ps 1.083 AH@
AH = ( - T- - )2 TMMd ( - p— 1) (5-12)
5.5 DWELL TIME
When EPA Method 5 or 17 is used for sampling, the dwell time at each
traverse point is the same. The measured concentration is a velocity-
weighted average for all points, as it should be for determination of emis-
sion rate, because the sampling rate is varied at each point proportionally
to point velocity. Because flow rate cannot be adjusted from point to point
with CSR, the dwell time at each point must be proportional to the point
velocity to obtain a velocity-weighted sample.
The dwell time for the first sample point is calculated before the run
is started in the following manner:
/APT (Total Run Time)
t. - - i -- : - (5-13)
Points)
where t^ *» dwell time at the first traverse point, rain
Apj « the expected AP at the first traverse point
(from a previous velocity traverse) , in. H.O
(/7TP) av = the average square root of AP from a previous velocity
traverse
At subsequent traverse, points, the velocity AP is measured and the dwell
time calculated using the actual AP recorded at the first point such that
36
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The number of minutes sampled at each point should be rounded to the nearest
1/4 rain.
-For sampling situations in which the stack temperature varies by more
than ±50 *F, the temperature must be factored into the dwell time calculation
to obtain a velocity-weighted rumple. The dwell time equations become
(Total Run Time)
(5-15)
(No. Points)
avg
t, /AP T
t » * n fl. (5-16)
/AP1 Tl
where T^ = stack temperature at the first traverse point, *R
T = the average stack temperature (from a previous velocity
traverse), *R
T » stack temperature at traverse point n, *R
The total sampling time given in equation 5-13 and 5-15 should be
greater than or equal to the minimum total sampling time specified in the
test procedures for the specific industry. Further/ it is required that (1)
the sampling time per point is not less than 2 min (or some greater time
interval if specified by the Administrator) and (2) the sample volume taken
(corrected to standard conditions) will exceed the required minimum total gas
sample volume. The expected total volume of gas to be sampled during a
single run may be approximated by using the sample flow rate and average run
time.
In some circumstances (e.g., batch cycles) it may be necessary to sample
for shorter times at the traverse points and to obtain smaller gas sample
volumes. In these cases, the approval of the Administrator should be
obtained.
5.6 PERFORMING THE CALCULATIONS
Calculation with the equations presented in the previous subsections may
be performed in a number of ways. A set of worksheets to be used for hand
calculation of the setup equations has been prepared. These worksheets are
shown in Figures 5-2, 5-3, and 5-4.
If the stack gas temperature changes such that it is outside ±50 *F of
the average used for the setup calculations, the setup parameters (sample
orifice AH and nozzle AP limits) should be recalculated. To save time during
the run, it is recommended that the setup calculations be performed prior to
sampling for a range of average stack temperatures. These temperatures
should be in increments of 50 degrees and span the range of expected stack
temperatures. This limits errors in the sample flow rate and nozzle AP
limits to approximately ±10%. A table is included in Figure 5-4 to facili-
tate this approach.
37
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CSR WORKSHEET I
SAMPLE FLOW RATE AND ORIFICE AH
Barometric Pressure, Pfl/ in. Hg
Stack Differential Pressure, Dp stacjc» in»
Average Stack Temperature, Tg, 'R -
Meter Temperature, TM, *R » _
Orifice AHg, in. H20 » _
Gas Analysis:
C02 fraction, f
02 fraction, fQ •
Water fraction, Bwg
Md - 44(fc) + 32(f0) + 28(1 - fc - fo) -
« * M(1 * B> * 18(BJ -
p PP stack .
s a 13.6
V » 51.05 + 0.207 Ts + 3.2355 x 1Q-5 Tg2 + 53.147(f )
- 74.143(Bwg) - ;
,M__ P,,-0 .
- 0.002837 8
-QS (1 " Bws)Ps-
, 1.083
« «a I — ir
S-i
f igure 5-2. CSR worksheet I • sample flow rate and orifice AA/ calculations.
38
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CSR WORKSHEET II
NOZZLE SELECTION
Barometric Pressure ?a, in. Hg »
Stack Differential Pressure, Dp gtackf in H20
Average Stack Temperature, TS, "R »
Meter Temperature, TJJ, *R * •
Sample Flowrate, Q_, acfin - •
Gas Analysis:
CO. fraction, f
0- fraction, f
Water fraction, BWS
CSR Pitot Coefficient, C.
"P
Method 2 Pitot Coefficient, C'
44 (fc> + 32 (f0) + 28(1
M(1 - B) * 18(B) »
p.p. DP stack
s a TT75
j » 51.05 * 0.207 Ts + 3.2355 x 10~5 Tfi2 * 53.147(fQ)
- 74.143 B._ -
3.056 Q.
u - , i *
Figure 5-3. CSR worksheet II • nozzle selection.
39
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°-2457 * '0.3072 -
0.2603 QC1/2 u,
,3/2
vaax " u
/ 0.2603 Q_1/2 u
* /0.5690 +
iP»in ' 1'3686 x 10"
-?aax * 1-3686 x 10
P M v
-!, 3 w :• max > 2
Nozzle ID
dn, in.
u, fps
v»in' «?«
Va«' f^
AP«in' in- H2°
Apmajt, in. 820
Velocity Traverse Data:
iP(CSR) « AP (Method 2)
- C
Port
Port
Port
Port
Point t
Soz ID iP Soz ID iP Noz ID
Noz ID
1
2
3
4
5-3. (Continued).
-------
CSR WORKSHEET III
DWELL TIME
Previous Method 2 data:
Total Run time, rain.
No. Traverse points
avg
Average T_ "R *
('AP)
Total run time
No. points
'A P.
avg
Note: If T varies by more than ±50*F from the average, T must be included
in the dwell time calculations as shown in Equations 5-15 and 5-16, which
include the factors /T1/Tavg and rTjy/tj in the equations for t. and tn,
respectively.
Ta, 'F
AH, in. HjO
dn, in.
Apmin APmax
min max
Apmin Apmax
APmin APmax
^
Point t
1
2
3
4
Port
Ap
Port
Ap
Port
Ap
Port
t Ap t
Figure 5-4. CSR worksheet III - dwell time calculations.
-------
SECTION 6
TAKING THE SAMPLE
6.1 FIELD ASSEMBLY
After the sampling system has arrived at the test site, it should be
visually inspected to determine if any damage was incurred during transport.
To check for internal probe damage, a positive-pressure leak check on each of
the lines running through the probe is recommended. To do this, one end of
each line should be blocked and positive pressure applied at the other. The
pressure on the line should be monitored with a manometer connected in
parallel. Failure to hold pressure indicates an internal probe leak, which
should be found and repaired before proceeding. '
When it has been determined the system is in proper operating condition,
the operator should begin assembling the system. The particle-sizing device
should be assembled as the operating manual dictates. The sampling nozzle
should then be attached to the sampler and the complete device mounted on the
probe. With the proper length of extension tubes, the pitot head should then
be mounted on the probe. The sampling nozzle and one leg of the pitot must
face the same direction while all the tubing unions are fully tightened. A
combined umbilical or individual tubing can then be used to connect the probe
to the control console. The sample line should be attached to the inlet of
the water dropout system (condenser and silica gel column), which is, in
turn, attached to the sample inlet of the control console. If available, an
umbilical which encloses the sample line and thermocouple extensions in a
single sheath is preferred.
Because the amount of water collected in the condensing system must be
known, all components of this system should be clean and free of any foreign
material. If silica gel columns are used, a preweight of the column and
silica gel should be obtained before any testing. Then the column must be
sealed until testing commences to avoid any accidental uptake of moisture.
After sampling, the column should be weighed again to determine the amount of
water uptake. If a condenser is used, it should be placed in an ice chest
and ice added to the chest until the condenser is sufficiently covered.
6.2 L2AK TEST
When the system has been completely assembled, the control console pump
may be used to leak-check the vacuum system as in Method 5:
e Plug the sampling nozzle and turn on the pump to produce a vacuum
across the desired test section.
o Use the fine-adjust valve to set the system vacuum to 15 in. Hg.
U2
-------
If the required vacuum reading on the console-mounted vacuum gauge cannot be
achieved or if the gas meter indicates a leak rate greater than 0.02 cfra, the
system is not sealed, and the leak(s) must be located and fixed.
The positive pressure portion of the control console can be tested for
leaks by using the procedure described in Method 5.
6.3 PRETEST EQUIPMENT WARM-UP
Because most flue streams, to be tested are not at ambient temperatures,
the CSR sampling device must be heated to stack conditions. This helps
ensure isokinetic sampling and significantly reduces the chance of acid
deposition within the sample line. The sampler should be heated in the gas
stream long enough to equilibrate with the temperature of the surrounding
stack gases. Typically, the PMiQ sampler should remain in the flue at least
15-20 nin to ensure thermal equilibrium. The nozzle, if uncapped, should not
point into the flow field during preheating* If possible, the nozzle should
be capped or plugged during preheating, and the cap or plug should be removed
immediately before sampling.
If the absolute pressure of the gas stream to be sampled is significant-
ly lower than ambient pressure, care must be taken to prevent rupturing the
filter when the sampler is inserted into the duct. In Method 5, this problem
may be avoided by starting the pump as the probe is inserted through the
port. Because of the preheat 'required with CSR, this method cannot be used.
If an in-stack filter configuration is used, the sample line should be
closed at the back end of the probe. However, because enough gas volume
remains in the probe to rupture the filter, steps must be taken to slowly
insert the probe into the stack. This allows the probe to gradually adjust
to the duct vacuum without rupturing the filter.
If the system is operated in a Method 5 configuration, a heated probe
should be used. The heating system should be adjusted to maintain a probe
temperature slightly greater than the gas dew point. If an in-stack filter
is used, a heated probe is not necessary. However, care should be used to
prevent condensed vapors from running back into the sampler. One solution is
to keep the probe inclined during operation.
6.4 SYSTEM START-UP
!*•
After the sampling device has preheated a sufficient length of time, the
nozzle cap (if one is used) should be removed and the nozzle turned into the
flow. The vacuum pump should be started and the sample line opened simulta-
neously. The sample orifice AH should then be adjusted to the appropriate
setting. The dwell time at the first traverse point should be that calcu-
lated from equation 5-13. The dwell time at each subsequent point should be
calculated during the run from equation 5-14.
If the stack temperature at any point in the traverse falls outside
-50 "p of the average used to calculate the operating parameters, a new
temperature range should be chosen and the operating parameters (AH and
-------
nozzle AP limits) corresponding to this new temperature range should be used.
Dwell times should be calculated using equations 5-15 and 5-16.
6.5 TRAVERSING
During traversing (moving to a new point or new port), all motion should
be smooth and brief to avoid bumping or vibrating the sampler. When removing
or inserting the sampler, care must be taken not to scrape the nozzle on the
port wall. Also, the sampler should not be allowed to bump against the far
inside wall of the duct.
6.6 SHUTDOWN ORIENTATION
The orientation of the sampler may require the operator to maintain an
appreciable flow rate while removing the sampler from the flue. The flow
rate should be maintained until the sampler can be placed in a favorable
orientation (usually horizontal}. This is particularly true when operating a
cyclone in a vertical orientation. Otherwise, some dust might fall from one
stage of the sampler to another and thus be measured where it was not
collected. Special care must be exercised to prevent contamination of the
sample by dust from the walls of the port. After the flow has been termi-
nated, the sampler can be transported to the laboratory. The sampler should
be kept in a horizontal position with the nozzle plugged or covered to avoid
contamination or loss of sample.
6.7 DATA LOGGING
The parameters of the test should be recorded in a clear, concise format
like that shown in Figure 6-1. Parameters that are likely to change, such as
stack temperature and velocity AP, should be recorded periodically. After
sampling at the first point, move to the next and immediately compare the
pitot A.
-------
Run
Code
Saapler
ID
Filter
ID
Sampler
Orientation
Sampling
Location
Nozzle
Diameter -ID (in)
Operator (s)
Date
Start
Time
End
Time
Sampling
Duration (min)
OGM
(initial)
DGM
(final)
Sample
Volume (ft3)
Dual Manometer Leveled and Zeroed?
Magnehelics Zeroed?
Gas Composition
%C02 Klj %CO
Moisture Content
Bun
Time
Port No
Trav.Pt.
Pi tot Leak Check
(Pos) (Neg)
AP
Pi tot
AH
Sample
DGM
Volume
Stack
Temperature (*F)
Differential Stack
Pressure (in. HjO)
Ambient
Temperature (*F)
Ambient
Pressure (in. Hg)
Gas
Velocity
System Leak Check
Notes
T
Stack
T
Probe
T
DGM
Dwell
Time*
/
aDwell Time, t.
Figure 6-1. CSff field data sheet.
45
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SECTION 7
SAMPLE RETRIEVAL
After the sampling system has been allowed to cool to a point where it
can be safely handled, the collected sample may be carefully recovered. The
recovery procedures described below are specifically for the configuration of
SRI/EPA Cyclone I. Different sampling devices may have different sample
recovery procedures, as described in the manufacturer's operating manuals and
in the literature.
7.1 RECOVERY OP THE PARTICOIATE MASS
Great care is needed during recovery of the collected particles from the
PMj0 sampler to ensure that all of the particulate matter is recovered and
placed in the proper sample containers. The sample can be effectively
recovered from both stages of the PM.Q sampler (cyclone and filter) by using
a combination of brushing and washing.
The first step in recovery of the particulate matter from the nozzle and
cyclone is brushing the collected mass into the appropriate foil envelope. A
clean no. 7 camel's hair brush or small nylon bristle brush is suggested for
this operation. The brushed surfaces should then be rinsed thoroughly with
acetone, or similar solvent, to recover any particles that continue to adhere
to the sampler. These rinses should be collected in a uniquely identified
sample container. The brush used for recovery should also be rinsed into
this container.
The filter should be recovered from the filter holder and returned to
the appropriate container. Any particulate matter or filter fibers adhering
to the filter holder surfaces or rubber 0-ring should be brushed onto the
surface of the filter. The interior surfaces of the filter holder should
then be rinsed with the solvent as described above.
As stated previously, assignment of the collected particulate matter to
the appropriate sample container is very important. Particulate matter
collected on the inner surfaces of the nozzle, the cyclone body, collection
cup and cap are to be considered as collected by the cyclone. ' Furthermore,
any matter brushed or rinsed from the outside of the cyclone exit tube is
also to be considered part of the cyclone catch. The PM,0 fraction consists
of particulate matter collected from the inner surface of the "turn-around"
on the cyclone cap, the inside wall of the exit tube, the inner walls of the
filter holder (upstream of the filter), and the surface of the filter.
Final weights for all particulate samples should be determined on site,
prior to shipment. Recommended procedures are outlined in Section 8.
46
-------
7.2 MOISTURE DETERMINATION
The condenser should be drained of any collected moisture and the amount
of liquid determined either volumetrically (to ± 1 mL) or gravimetrically (to
± 0.5 g). The liquid may be discarded after the weight or volume is record-
ed. The spent silica gel should be weighed in the appropriate container
(such as the drying column or shipment container) to determine the moisture
uptake.
-------
SECTION 8
POSTSAMPLING CHECKS
Posttest activities for a CSV. system involve equipment calibration
checks, field sample analysis, and equipment maintenance. The first two
items are discussed in this section. The third item is discussed in
Section 10 of this manual.
8.1 EQUIPMENT CALIBRATION CHECKS
A posttest calibration check of the flow metering devices is required.
The posttest calibration check should be performed as described in Section 3
of this manual. If the gas meter correction factor obtained from the cali-
bration check deviates from the initial calibration factor by more than 5%,
the meter should be recalibrated. The posttest data reduction should then be
performed with whichever calibration factor yields the lower gas meter
volumes.
Calibration checks should also be performed on the stack and dry gas
meter thermocouples. Ea*h of the above temperature sensors should be
compared with a mercury-in-glass thermometer at ambient temperature. If the
stack temperature thermocouple reading differs from the reference by more
than 1.5% of the absolute temperature, the thermocouple should be recali-
brated as described in Section 3. The old and new calibrations should be
compared to determine the sign and magnitude of the correction to be applied
to the average stack temperature. If the dry gas meter thermocouple reading
varies from the reference by more than 6 "C (10.8 *F), the thermocouple
should be recalibrated. For data reduction calculations, the calibrations
which give the higher gas meter temperature should be used.
A posttest calibration check is also required for the system Magnehelic*
gauges. This calibration check should be performed as described in
Section 3.
8.2 SAMPLE ANALYSIS
Analysis of the field samples is essentially the same as for Method 5.
Filter and cyclone catches should desiccate for a minimum of 24 h before the
initial weighing. Each sample should be weighed to a constant weight, which
is achieved when the difference between consecutive weighings is no more than
0.5 mg or 1% of the total weight less tare weight, whichever is greater; at
least 6 h of desiccation time should be allowed between weighings.
48
-------
As an alternative, the samples may be oven dried at the average stack
temperature or 220 *F, whichever is less, for 2 to 3 h, cooled in a desicca-
tor, and weighed to a constant weight. The tester may also opt to oven dry
the samples as described above, weigh the samples and use this as the final
weight. Whichever option.is chosen, final weights of all cyclone and filter
samples should be determined to the nearest 0.1 rag on site, before shipping.
Acetone rinse and blank samples should be inspected to confirm that no
leakage has occurred. If a noticeable amount of sample has been lost through
leakage, the sample must be either declared void or corrected in the final
results with methods approved by the sponsoring agency. The liquid should be
measured either volumetrically to ±1 mL or gravimetrically to ±0.5 g. Each
sample should be evaporated to dryness at ambient temperature and pressure in
a tared 250-mL beaker or similar container. The evaporated samples should be
desiccated for 24 h and weighed to a constant weight. Results should be
recorded to the nearest 0.1 rag.
If the silica gel is not analyzed in the field, the spent silica gel
samples should be weighed in the appropriate container to the nearest 0.5 g.
49
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SECTION 9
DATA ANALYSIS
9.1 VELOCITY-WEIGHTED AVERAGES
If the velocity distribution at the sampling plane is such that two or
more nozzle sizes are required to complete a traverse or if the stack
temperature variation exceeds ±50 *F so that new setup parameters are
required during the run, a velocity-weighted average of the stack temperature
and particulate concentration must be calculated. For a generic data term,
D, this equation takes the form
n
15 " I I Di fci (9'1)
rj=1
where T5 * the velocity-weighted average of D
D. = average value of D for each nozzle size
6 * total run time
t. » run time for each nozzle size
n = number of component changes
For the remainder of this section, the term "run" will refer to that portion
of a traverse performed without any component, changes.
9.2 DRY GAS METER VOLUME
The sample volume measured by the dry gas meter can be corrected to
standard conditions (68 *F, 29.92 in. Hg) by using the following equation:
/p + AH^
My) | a ^ I
- 17.65 (vMy) f a v™76] (9-2)
9.3 VOLUME OF WATER VAPOR
The volume of the water vapor collected from flue gas is calculated as
follows:
pH2o VST
V = Vo * _
^ MH20 PST
- 0.04707 V^c (9-3)
50
-------
9.4 PERCENT MOISTURE CONTENT
The moisture content of the stack (or sample) gas is calculated by the
equation
VWS
BWS = „—,-g— (9-4)
ws VMS * VWS
9.5 STACK GAS MOIJEC0IAR WEIGHT
Md = 32 (f0) + 44 (fc) + 28 (1 - fQ - fc) (5-1)
Mw = Md (1 ' Bws} + 18 (Bws} (5-2>
9.6 STACK GAS VISCOSITY
The viscosity of the stack gas may be calculated from the following
equation (Williamson et al., 1983):
W - Cj + C2TS + C3TS2 + C,BWS + C5f0 (5-4)
where u is in micropoise, T in *C, and
Cj - 160.62
Cfe-- 0.42952
C3 - 1.0483 x 10"^
Q, - -74.143
Cg » 53.147
or for T in *R
Cr = 51.05
C2 - 0.207
C3 - 3.24 x 10~5
Q, - -74.143
Cj .- 53.147
9.7 SAMPLE PLOW RATE
The sample flow rate, at standard conditions, can be found by using the
following equation:
VMS
Q. ' ' ~— (9~5)
SST 8
However, to calculate the particle cut diameter of the inertial classi-
fier, it is necessary to know the flow rate through the sampler at the actual
sampler conditions. This can be accomplished by using the following equa-
tion:
51
-------
ST 1 - Bws TST
= 0.056 Qg IT 1 B—) l-p^J (9-6)
9.8 SAMPLER D5n
The D^g or cut-point of each stage of the chosen particle-sizing device
should be calculated for accurate determination of the particle size distri-
bution. The cut-point is primarily a function of the actual flow rate
through the sampler and the viscosity and density of the stack gas.
The currently available data concerning calibration of the SRI/EPA
Cyclone I show the behavior to be described by the equation
05,3 = 0.15625 (j£) -0-2091 Qg-0-7091 U0.7091 (9_7)
If another inert ial sizing device is used in conjunction with CSR, the D50's
for each of the stages should be calculated as described in the vendor-
supplied operator's manual.
9.9 STACK GAS VELOCITY
The stack gas velocity can be found by using the following equation:
T 1/2
9.10 NOZZLE VELOCITY
The nozzle velocity (u) , constant for a specific nozzle diameter (d) ,
nay be calculated from the following equation:
3.056 Qg
U —
9.11 NOZZLE £P LIMITS
(9-9)
For each nozzle and stack gas temperature range, limits on acceptable
velocity pressure differentials, AP . and AP_ , were calculated from equa-
IBH1
tions 5-8 and 5-9 of the setup calculations. To determine if the run was
performed within these limits, the actual stack temperature and velocity AP
at each traverse point should be tabulated and compared with the limits,
~pain an
-------
9.12 PERCENT ISOKINETIC SAMPLING
The following equation should be used to determine the percentage of
isofcineti'c sampling:
U677 T8 [0.002.67 V£c +-(£-(Pa + ^5 ]
1% -- „ ^ ps ^ • - - - (9-10,
9.13 CONCENTRATION
The concentration of the particulate matter caught by each stage in
grains per standard cubic foot can be calculated by the equation below
Mp
C^, * 0.0154 (.y — ) (9-11)
nS
The units can be converted to milligrams per dry normal cubic meter by
using the following:
C_ » 2293.2 C' (9-12)
mm
9.14 ACCEPTANCE CRITERIA
To be acceptable, each run must meet the following criteria:
1) The velocity at each traverse point must be within the velocity
limits for the nozzle used, or the velocity at one point may be below
the minimum for the nozzle if the percent isokinetic falls within
100 - 20%. This second specification allows for the acceptance of
data with a positive bias but which are still within allowable error
limits.
2) For single stage PM samplers .
o iVn must be 10 ± 1 urn.
For multiple stage PM, 0 samplers
o one stage cut must be at or greater than 10 urn and two succeeding
size cuts must be le.°s than 10 urn
o separation between successive size cuts must be no more than a
factor of 2 and no less than a factor of 1.S
o the product of jet velocity and size cut for each stage with cut
above 2 urn should satisfy the criteria given by McCain et al.
(1986).
53
-------
SECTION 10
MAINTENANC2
A notebook or other record of all maintenance procedures should be kept.
This will provide a definite and current record of all information pertinent
to reliable operation of the CSR sampling system. Maintenance of the system
should be performed as described previously (Rom, 1972), with the exceptions
noted below.
10.1 VACUUM SYSTEM
The vacuum system may be checked as follows:
o Insert a plugged 0.5-in. male quick connect into the sample inlet
of the control console.
o Turn the pump switch to ON.
o Turn th<- coarse-adjust valve to the ON position.
o Close fully the fine-adjust valve.
The vacuum gauge should read about 25 in. Hg when ambient barometric pressure
is near 30 in. Hg. If this pressure cannot be achieved, a leak or sticking
pu»p vane should be suspected. If the leakage rate measured by the dry gas
•eter exceeds 0.02 cfm, the leak or leaks must be found and corrected. Parts
to check are the pump, vacuum gauge, metering valves, and tubing.
10.2 VACUCH POM?
Host pump trouble can be corrected by flushing the unit according to the
manufacturer's instructions rather than disassembly. A noisy or inefficient
pump is frequently caused by nothing more serious than a vane stuck in a
rocor slot because of foreign material in the unit. To flush the unit,
follow the procedure given below:
o Separate the pump from the system.
e Slowly add several teaspoons of solvent at the intake while the
unit is running (recommended commercial solvents include Loctite
Safety Solvent, Inhibisol Safety Solvent, or Dow Chemical
Chlorothane).
« Lay the unit on its side with the outlet downward so the solvent
will work out again.
-------
10.3 MAGNEHELIC* DIFFERENTIAL PRESSURE GAUGES
Magnehelic* differential pressure gauges are precision instruments
assembled and precalibrated by the manufacturer. If trained instrument
mechanics are not available, it is recommended that any instruments requiring
repair be returned to the factory.
No lubrication or periodic servicing is required. If the interior is
protected from dust, dirt, and corrosive gases and fluids, years of trouble-
free service may be expected.
10.3.1 Zero Adjustment
The indicating pointer should be set exactly on che zero mark by using
the external zero-adjust screw on the cover at the bottom. The zero check or
adjustment can be made only if the high-pressure and low-pressure taps are
both open to atmosphere.
10.3.2 Calibration Check
For service requiring a high degree of continued accuracy, periodic
calibration checks are recommended. In general, the Magnehelic* calibration
should be checked by following the procedure below.
1. As a comparison gauge, use a hook gauge, micromanometer, or inclined
gauge of known accuracy.
2. Connect the Magnehelic* gauge and reference gauge with two leads from a
"T." Connect rubber tubing to the third leg of the "T," and impose the
.-fissure, slowly.
3. Be certain no leaks exist in the system, and provide adequate time for
comparison gauges to reach equilibrium, because fluid drainage and
different dynamic characteristics can affect the reading.
10.3.3 Recalibration
1. Remove the plastic cover.
2. Remove the two screws holding the scale, and slide the scale out, using
care not to damage the pointer.
3. Loosen the two set screws in the range spring clamp (Dwyer part no.
NUA-70B); move toward the helix to increase the range and back to
decrease. Secure the clamp with the set screws, replace the scale,
check the gauge zero, and compare readings as in Section 10.3.2.
4. Replace the cover. The cover must be tight and leakproof for accurate
readings on the high-pressure side. Observe the following procedure.
a. Place the cover in position with the notch engaged and with the
O-ring properly seated.
55
-------
b. Jockey the zero-adjust screw into position so its hex end is
inserted in the socket set screw, which actuates the zero-adjusting
mechanism.
c. Hold the cover in position and screw the bezel down snuggly. The
0-ring must take some squeeze to effect an airtight seal.
Caution: If the bezel binds because of galling action of aluminum
surfaces, lubricate sparingly with light oil or molybdenum sulfate
compound.
d. Troubleshooting.
1. Gauge sluggish.
- Leads may be plugged or leaking.
- Cover may be loose or leaking.
- Pointer may be touching scale.
- Jewels supporting helix may be overtightened.
2. Gauge fails to indicate zero properly.
- See comments above regarding sluggish readings.
- Iron particles may be in a strong magnetic field between helix
and magnet. If found, they may be removed by touching each
particle and withdrawing it with a small screw driver.
- Magnet may be shifted and touching helix.
3. Apparent inaccuracy.
- See preceding comments.
- Improper connections to pick up desired differential.
4. Consult factory for unusual conditions of temperature, pressure,
etc., and the effect on gauge operation and accuracy.
10.4 DUAL MANOMETER
The dual manometer may be checked as follows:
o Visually check the pitot and orifice manometer lines to ensure they
are free of fluid.
o Check for leaks, especially around the fluid-level zeroing controls
and drain screws.
o Wipe the dual manometer clean. The back can be cleaned with
compressed air, or the device can be removed from the control panel
and wiped clean.
o if the dual manometer is unusually dirty, clean as recommended on
the instruction plate.
o Make sure that the manometer ports are open (1-1/2 turns counter-
clockwise from the seat) and the manometer lines are connected.
o Level the manometer and check the,fluid level.
o TO fill the manometer with fluid, remove the screw on the left
side. When the oil meniscus and the reflected image at zero are
aligned, the fluid-level plunger (zeroing control) should have
about 1/4 to 1/2 in. travel inward.
56
-------
Note; During rough shipment, the manometer lines should be
disconnected and the manometer ports closed by turning clockwise
until sealed.
o If for any reason the manometer unit has been inverted, be sure the
floating check valves of the manometer have returned to their
normal position. These floating valves are located under the
manometer ports and must be in the normal position when the
manometer is used.
10.5 PITOT TUBE
The pitot tube should occasionally be inspected for any deformation of
the pressure inlets, because this may change the pitot calibration coeffi-
cient. Any dents or nicks should be repaired or the pitot head should be
replaced if the damage warrants it. Before each test run, the operator
should blow gently into each pitot inlet to check for obstructions. If the
pitot tube lines are clear, the pitot tube gauge will respond. If no
response is noted, the operator should blow out the pitot lines with
compressed air. The pitot tube can be checked for leaks by plugging one end
of the tube and applying a positive pressure at the opposite end. If the
tube will not maintain pressure, a soap solution can be used to identify the
location of any leaks.
10.6 NOZZLES
The sample nozzle should be visually inspected before any testing. If
repair is necessary, a plumb bob should be used for inside damage and emery
paper for outside damage. After any nozzle repair, the nozzle diameter
should be remeasured. The knife edge of the nozzle should be covered with
serum caps or similar covers to avoid damage when the nozzle is not in use.
10.7 THERMOCOUPLES
The thermocouples throughout the system should occasionally be checked
against room temperature by using a mercury-in-glass thermometer as the
standard. If any thermocouples do not read within ±5 "C, the thermocouples
or readout should be replaced or recalibrated.
10.8 SAMPLING PROBE
10.8.1 Probe Cleaning
Before each field test, all lines of the sampling probe, including the
pitot tube lines, should be cleaned according to the procedure outlined
below.
o Clean the probe internally by rinsing, first with tap water, then
with distilled, deionized water, then with acetone or dichloro-
me thane.
57
-------
o Rinse the internal tubes with the chosen organic solvent and allow
them to air dry.
o visually inspect the probe for cleanliness, and repeat the proce-
dure if necessary.
o Rinse the pitot lines with water and blow them out with compressed
air.
10.8.2 Probe Heater Check
The procedure below may be used to check the probe heater.
o Plug the probe heater line and controlling thermocouple into the
control case, and turn the heat controller on.
The indicator light on the controller should come on, and the probe
should become warm to the touch in a few minutes. After a few
minutes, the indicator light should begin to cycle on and off.
o If the probe does not heat, check the probe for loose connections.
o if the probe still does not heat, remove the probe liner from the
probe sheath for inspection of the heating element.
o After the probe lines have been removed, unwrap the insulation and
visually inspect the probe heating element for shorts or burned
spots. An ohmmeter can also be used to measure the resistance
between leads (approximately 17 ohms) and also to ground (infi-
nite). Deviations from these values indicate faulty wiring.
o After any electrical problem has been solved, rewrap the probe
lines with insulating material, and reassemble the probe.
10.9 CONDENSING SYSTEM
If the CSR sampling train is operated in a Method 17 configuration, a
condenser and silica gel column may replace the Method 5 impinger tra:-.
assembly. An impinger system will be required if the "back-half" catch is to
be measured. Whichever system is used for collection of water vapor from the
sampled stack gas, it must be clean and free of leaks before being used.
Glass impingecs should be cleaned with distilled, deionized water and then
acetone and should then be allowed to air dry. Stainless steel condensers
should also be rinsed by the same procedure and allowed to air dry, inverted
to ensure total drainage. The drying can be speeded by blowing out the
condenser with compressed air. Silica gel columns (along with condensers)
should be leak tested, along with the control box or separately, by applying
positive pressure at the inlet and plugging the outlet. Ideally, these
devices should maintain a pressure of at least 10 in. Hg above absolute.
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SECTION 11
AUDITING PROCEDURES
Routine quality assurance activities, such as equipment calibrations,
are essential to obtaining good data. An assessment of the quality of these
data may be made through an audit. The audit must be performed with equip-
ment or standards independent of those used for actual measurements to ensure
that the tasks involved are being performed properly.
The audits recommended for use in a program using the CSR method are
similar to those described for Method 5 (U.S. Environmental Protection
Agency, 1977, Section 3.4.8). Two types of audits, performance and system,
are commonly performed.
Performance audits provide a quantitative evaluation of the quality of
data produced by a measurement system. One type of performance audit recom-
mended for Method 5 assesses the accuracy of a system's flow metering devices
with a critical flow orifice. This is also recommended for measurement pro-
grams using the CSR.
A performance audit of data processing is also recommended. As for
Method 5, an audit of this type can uncover and eliminate errors in data
transfer, calculations, etc. The flow of data from field data forms and
weight sheets to data reduction programs or hand calculations should be
traced for at least a portion of the data base. Calculation of results for &
standard data set is another method by which data reduction procedures may be
audited. .
A system audit is a qualitative inspection and examination of the proce-
dures and techniques used by the field team. This type of audit is strongly
recommended .if the team is not familiar with the CSR method.
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r
SECTION 12
RECOMMENDED STANDARDS FOR ESTABLISHING TRACEABILITY
Although the use of quality control checks and independent audits is
essential to obtaining data of the desired quality, another important consid-
eration is the traceability of individual elements of the measurement
process. All materials, equipment, and procedures used should be traceable
to a standard of reference.
Working calibration standards should be traceable to primary or higher
level standards. The system's flow metering devices should be calibrated
against a wet test meter which has been verified as required for Method 5
(U.S. EPA, 1977). The performance of the analytical balance should be
checked against class-S weights that are traceable to MBS standards.
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REFERENCES
Belyaev, S. P. and L. M. Levin. Investigation of Aerosol Aspiration by
Photographing Particle Tracks under Flash Illumination. J. Aerosol Sci.
3:127-140, 1972.
Belyaev, S. P. and L. M. Levin. Techniques for Collection of
Representative Samples. J. Aerosol Sci. 5:325-338, 1974.
Farthing, W. E. Evaluation and Recommendations of Protocols for PM1Q in
Process Streams: Recommended Methods; Volume I. SRI-EAS-83-1038,
Southern Research Institute, Birmingham, AL, 1983.
Farthing, W. E. and A. 0. Williamson. "A Unified View of Inertial
Impactors and Cyclones." Presented at 1985 Annual Meeting of American
Association for Aerosol Research, Albuquerque, NM, 1985.
McCain, J. 0., S. S. Dawes, J. W. Ragland, A. D. Williamson. Procedures
Manual for the Recommended ARB Particle Size Distribution Method
(Cascade Impactors). NTIS PB 86-218666 California Air Resources Board,
1986.
Rom, J. J. Maintenance, Calibration, and Operation of Isokinetic Source
Sampling Equipment. APTO-0576, U.S. Environmental Protection Agency,
Research Triangle Park, NC, March 1972.
Shigehara, R. T. Proposed Revisions to Reduce Number of Traverse Points
in Method 1 - Background Information Document. EPA-450/3-82-016a, O.S.
Environmental Protection Agency, Research Triangle Park, NC, 1982.
Smith, W. B., D. B. Harris, and R. R. Wilson, Jr. A Five-Stage Cyclone
System for In Situ Sampling. Environ. Sci. Technol. 13(11): 1387-1392,
1979.
U.S. Environmental Protection Agency - EPA Method 1. 40 CFR Part 60,
Appendix A.
U.S. Environmental Protection Agency - EPA Method 2. 40 CFR Part 60,
Appendix A.
U.S. Environmental Protection Agency - EPA Method 3. 40 CFR Part 60,
Appendix A.
U.S. Environmental Protection. Agency - EPA Method 4. 40 CFR Part 60,
Appendix A.
61
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REFERENCES (Continued)
U.S. Environmental Protection Agency - EPA Method 5. 40 CFR Part 60,
Appendix A.
U.S. Environmental Protection Agency - EPA Method 6. 40 CFR Part 60,
Appendix A.
U.S. Environmental Protection Agency - EPA Method 17. 40 CFR Part 60,
Appendix A.
U. S. Environmental Protection Agency. Quality Assurance Handbook for
Air Pollution Measurement Systems, Volume III: Stationary Source
Specific Methods. EPA-600/2-77-026, U.S. Environmental Protection
Agency, Research Triangle Park, NC, 1977.
Wilke, C. R. A Viscosity Equation for Gas Mixtures. J. Chera. Phys.
8:517, 1950.
Williamson, A. D., D. L. lozia, P. V. Bush, W. E. Farthing, J. D.
McCain, and W. B. Smith. Development, Application, and Support of
Particulate Sampling Procedures. Third Annual Report (1982).
SRI-EAS-83-348, Southern Research Institute, Birmingham, AL, 1983.
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GLOSSARY
Aerodynamic diameter: The aerodynamic diameter of a particle is the diameter
of a sphere of unit density whch has the same settling velocity in the
gas as the particle of interest. For spherical particles with diameter
Dp, larger than a few microns and gas conditions of interest for source
PMjg, the aerodynamic diameter is essentially given by /p~~ D where p
is the particle density. P P
Cut-point: The cut-point of a size classifier is the particle diameter for
which all particles of equal or greater diameter are captured and all
particles with smaller diameters are not captured. No real device
actually has a sharp step function cut-point, but the theoretically
defined D of a stage is often called its cut-point.
Geometric standard deviation, o : A measure of dispersion in a lognormal
distribution. It can be calculated as the ratio of particle diameter
corresponding to a cumulative percent of 50 to the diameter
corresponding to a cumulative percent of 15.86.
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