United States
Environmental Protection
Agency
Environmental Monitoring and Support
Laboratory
Research Triangle Park NC 27711
EPA-600 4-8C
April 1980
Research and Development
&EPA
A Study to Improve
EPA Methods 15 and
1 6 for Reduced
Sulfur Compounds
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL MONITORING series.
This series describes research conducted to develop new or improved methods
and instrumentation for the identification and quantification of environmental
pollutants at the lowest conceivably significant concentrations. It also includes
studies to determine the ambient concentrations of pollutants in the environment
and/or the variance of pollutants as a function of time or meteorological factors.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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A STUDY TO IMPROVE EPA METHODS 15 AND 16
FOR REDUCED SULFUR COMPOUNDS
by
Henry F. Hamil and Nellie F. Swynnerton
Southwest Research Institute
San Antonio, Texas 28284
SwRI Project 01-4842-016
EPA Contract 68-02-2489
Dr. Joseph E. Knoll
Quality Assurance Division
Environmental Monitoring Systems Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
ENVIRONMENTAL MONITORING SYSTEMS LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
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DISCLAIMER
This report has been reviewed by the Environmental Monitoring Systems
Laboratory, U.S. Environmental Protection Agency, and approved for publication.
Approval does not signify that the contents necessarily reflect the views and
policies of the U.S. Environmental Protection Agency, nor does mention of trade
names or commercial products constitute endorsement or recommendation for use.
n
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FOREWORD
Measurement and monitoring research efforts are designed to anticipate
potential 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 means of monitoring compliance with regulations and
to evaluate the effectiveness of health and environmental protection efforts
through the monitoring of long-term trends. The Environmental Monitoring
Systems Laboratory, Research Triangle Park, North Carolina has responsibility
for: assessment of environmental monitoring technology and systems; implemen-
tation of agency-wide quality assurance programs for air pollution measurement
systems; and supplying technical support to other groups in the Agency including
the Office of Air, Noise and Radiation, the Office of Toxic Substances and the
Office of Enforcement.
The following investigation was conducted at the request of the Office
of Air Quality Planning and Standards. Test methods for the measurement of
reduced sulfur compounds from stationary sources were evaluated. The work
included studies of techniques and procedures for the gas chromatographic
measurement of sulfur compounds commonly emitted from Kraft pulp mills and
Claus sulfur recovery plants, permeation devices used as standards in those
measurements, and the efficacy of compressed gas mixtures of sulfur compounds
for use as quality assurance materials. Some information was also obtained
on the comparative values of electrolytic conductivity and flame photometric
detectors as devices for measuring reduced sulfur compounds.
Thomas R. Mauser, Ph.D.
Director
Environmental Monitoring Systems Laboratory
Research Triangle Park, North Carolina
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ABSTRACT
Equipment and procedures for the analysis of total reduced sulfur
compounds according to EPA Methods 15 and 16 were studied.
A detector operating on the electrolytic conductivity principle
was found to be equal or superior to the flame photometric detector
for the analysis of H£S, COS, C$2, MeSH, DMS, and DMDS in the laboratory.
Adsorption of these species on surfaces of the chromatographic system
was found to be the main source of imprecision and inaccuracy in the
analysis. Commercial samples of silica gel for analysis of H2S and
COS had to be given a pretreatment before they would provide the necessary
separation. Glass and nickel tubing were used in the preparation
of GC columns but were found to adsorb greater amounts of the sulfur
compounds than FEP Teflon columns. Permeation devices containing
the above sulfur compounds were found to permeate at uniform rates
after one year of use, but observed rates did not agree well with
vendor-certified rates in all cases. Aluminum cylinders containing
mixtures of H2S, COS and C$2 and mixtures of H2S, MeSH, DMS, and DMDS
were periodically analyzed over four months. Results were erratic,
and no firm conclusions as to stabilities of the mixtures could be
drawn. The inherent inaccuracy of the chromatographic system used
is likely to have been responsible for the data scatter.
IV
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CONTENTS
Foreword iii
Abstract iv
Figures vi
Tables vii
Abbreviations and Symbols viii
1, Introduction 1
2. Conclusions 2
3. Experimental 5
4. Results and Discussion 9
Flame photometric detector 9
Hall 700A electrolytic conductivity detector 17
Columns and systems 23
Permeation tube study . 27
Gas cylinder stability study 28
Dilution system 39
Field studies 39
References 41
Appendix 43
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FIGURES
Number Page
1. H2S calibration curves at two volumes 10
2. COS calibration curves at two volumes 11
3. CS2 calibration curves at two volumes 12
4. H2S peak growth with glass and with metal FPD jets. ... 18
5. COS peak growth with glass and with metal FPD jets. ... 18
6. CS2 peak growth with glass and with metal FPD jets. ... 18
7. Typical calibration curves with Hall 700A ECD 19
8. FPD and Hall 700A ECD responses 22
9. Hall 700A ECD reactor-conductivity cell 24
10. Effect of tubing material on peak shapes 25
11. Gravimetric calibration of H2S permeation device 29
12. Gravimetric calibration of COS permeation device 30
13. Gravimetric calibration of CS2 permeation device 31
14. Gravimetric calibration of MeSH permeation device .... 32
15. Gravimetric calibration of DMS permeation device 33
16. Gravimetric calibration of DMDS permeation device .... 34
17. Top view of oven containing two-stage dilution system . . 40
VI
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TABLES
Number Page
1. FPD Response to H2S Concentration 14
2. FPD Response to COS Concentration 14
3. FPD Response to CS2 Concentration 15
4. Hall 700A ECD Response to COS Concentration 20
5. Hall 700A ECD Response to H2S Concentration 20
6. Hall 700A ECD Response to C$2 Concentration 20
7. Comparison of FPD and Hall 700A ECD Responses 21
8. Comparison of Experimentally-Determined and Vendor-
Certified Permeation Rates 35
9. Gas Cylinder Stability Study - Method 15 36
10. Gas Cylinder Stability Study - Method 16 37
vii
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LIST OF ABBREVIATIONS AND SYMBOLS
Abbreviations
°C — degree Celsius
EPA ~ U.S. Environmental Protection Agency
ft ~ foot
in — inch
tnin — minute
ng — nanogram
ppm — part per million
mL — mill il Her
m — meter
mm — millimeter
Symbol s
~ hydrogen sulfide
COS — carbonoxysulfide
CSg — carbon di sulfide
MeSH — methane thiol
DMS ~ dimethyl sulfide
DMDS — dimethyl di sulfide
FEP — fluorinated ethylene propylene
ECD — electrolytic conductivity detector
FPD ~ flame photometric detector
N£ ~ nitrogen
TRS ~ total reduced sulfur
GC — gas chromatograph
ID — inside diameter
viii
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SECTION 1
INTRODUCTION
This draft report concerns studies of EPA Methods 15 and 16,
work performed in our laboratories as well as that reported in the
recent literature. The goals were to gain intimate familiarity with
the methods, in particular, and with the techniques of trace sulfur
gas analysis, in general, and to perform specified studies designed
to evaluate and perhaps improve the subject methods. Work Assignments
specified that the following be studied:
1) The stabilities (variation of permeation rates with
time) of permeation tubes containing hydrogen sulfide
(H2S), carbonoxysulfide (COS), carbon disulfide (C$2),
methane thiol (MeSH), dimethyl sulfide (DMS) and dimethyl
disulfide (DMDS)
2) The stabilities (compatabilities) of bottled gas mixtures
containing the above compounds in an inert gas
3) Interferences that may result from the presence of
nonsulfurous substances
4) Methods for improving the dilution system
5) The performance of a conductivity detector as an alternative
to the flame photometric detector (FPD)
6) The location of suitable sources for field testing
of the methods.
In addition, several chromatographic systems developed in other
laboratories are described. These include isothermal systems which
allow the analysis of the four total reduced sulfur (TRS) compounds
covered in Method 16 using a single instrument.
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SECTION 2
CONCLUSIONS
At the time studies were begun, chromatographic equipment and
conditions to be used were specified by the methods (Method 15 - Federal
Register 41, pp. 43870-43873, October 4, 1976; Method 16 - Federal
Register 41, pp. 42017-42020, September 24, 1976). Later, these regulations
were modified (Method 15 - Federal Register 43, pp. 10866-10873, March 15,
1978; Method 16 - Federal Register 43, pp. 7568-7598, February 23,
1978) to allow other separation columns and conditions to be used
provided they met certain criteria. Early laboratory investigations,
then, were carried out using systems fabricated according to Section
12 of both methods. Instrumentation and equipment are described in
Section 3, "Experimental".
The required flame photometric detector (FPD), while possessing
the required sensitivity and selectivity, suffers from a nonlinear
response and a limited dynamic range in the sulfur mode. Its signal
is also affected (quenched) by the presence of non-sulfur-containing
compounds which may coelute with the TRS compounds. A commercially-
available detector operating on the electrolytic conductivity principle
was evaluated in side-by-side laboratory test.; and found to be equal
or superior to the FPD with regard to sensitivity, selectivity and
behavior toward certain interferences. Its response was essentially
linear over the range of interest. This detector should at least
be considered as an alternative to the FPD, that is, it is felt the
FPD should not be specified as the detector to be used in the methods
a priori.
A deactivated silica gel column for analysis of the Method 15
compounds (COS, H2S and C$2) was found to outperform all other columns
tested provided that the substrate was pretreated with an acid wash.
Commercial deactivated silica gel used "as received" was able to separate
the materials of interest only at temperatures near ambient (25°C)
and low carrier gas flow rates (20 mL/min). After a wash with concentrated
hydrochloric acid, the same silica gel gave baseline separation of
COS and H2S at 55-60°C.
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GC columns constructed of FEP Teflon tended to develop leaks
with time due to the "cold flow" characteristic of the material.
Columns constructed of glass and nickel tubing did not leak, but use
of the metal column resulted in a partial loss of all Method 15 compounds.
Compared to the Teflon column, the nickel column caused a loss of
15 percent of the COS, 65 percent of the H2S and 17 percent of the
C$2* The glass column lost 21 percent of the H2S. Thus, it appears
that glass columns may be used in place of Teflon columns at a sacrifice
in apparent sensitivity.
No isothermal separation of the four TRS compounds of Method
16 could be attained without the use of backflush techniques. Temperature
programming allows this separation, but such a technique was determined
to be unacceptable due to lengthy analysis time and leak problems
caused by the "cold flow" of Teflon columns and fittings at elevated
temperatures.
Several systems employing a backflush cycle have been found to
perform the requisite Method 16 analysis in about ten minutes using
a single instrument.
Permeation tubes of the O'Keeffe-type1*2 containing H£S, C$2,
MeSH, DMS and DMDS were found to permeate at a constant rate over
a three-month period one year after date of purchase. The experimentally-
determined rates were, in general, in fair agreement with those certified
by the vendor.
A wafer-type device containing COS was also found to permeate
uniformly after one year; however, its certified rate (790 ng/min)
and observed rate (628 ng/min) did not agree. It is recommended that
vendor-certified permeation rates be checked experimentally by the
purchaser.
Aluminum cylinders containing low-ppm concentrations of COS,
H2S and CS2 in N2, and H2S, MeSH, DMS and DMDS in N2 were analyzed
periodically over four months. A cylinder originally containing sub-
ppm amounts of COS, H2$, and C$2 showed no COS or H2S after two months,
while the C$2 remained constant. Cylinders originally containing
greater than one ppm of COS, ^3 and C$2 were essentially unchanged
after four months.
Within the apparent accuracy of Method 16, analysis of cylinders
containing the four subject gases did not vary over the test period.
The use of these mixtures for in-the-field instrument calibration
should be tested under rigorous field conditions.
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All attempts to build a workable dilution system using the Komhyr
A-150 pumps failed. When a back pressure of more than 1-2 cm Hg was
encountered by the pump, it leaked at the pump head. The leak rate
is sensitive to small changes in back pressure; therefore, dilution
factors cannot be known with accuracy. A simple working dilution
device was designed and shown to give precise results at ambient conditions
with synthetic gas blends. This system is based on pressure-regulated
flow through capillary tubing.
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SECTION 3
EXPERIMENTAL
Gas Chromatographs:
Calibration system:
Hewlett-Packard 5710A equipped with
a Mel par Flame Photometric Detector
(FPD), strip chart recorder, and A/D
converter connected to a Hewlett-Packard
Model 3354 Laboratory Data System.
Attenuation range = IX to 1024X.
Tracer Model 560 equipped with a Hall
700A Electrolytic Conductivity Detector
(ECD), strip chart recorder and connected
to the above-listed Hewlett-Packard
integrator with an A/D converter.
O'Keeffe-type1'2 permeation tubes containing
H2S, CS£, MeSH, DMS, and DMDS and a
wafer-type device containing COS were
purchased from Metronics, Inc., Palo
Alto, California and were individually
certified by the vendor.
Rate,
Compound
H2S
COS
CS2
MeSH
DMS
DMDS
Certified Permeation
ng/mi n
690 ± 2%
790 ± 5%
600 ± 2%
380 ± 2%
520 ± 2%
109 ± 5%
A Lauda Model B-l water bath controlled
at 30° ±0.1°C kept the tubes at the
temperature of their certification.
-------
Once a week the tubes were removed from the tube chambers and
weighed on a Mettler H51AR analytical balance with readability of
0.01 mg and precision (standard deviation) of ±0.01 mg. Tubes were
handled using clean cotton gloves, and static charge was dissipated
by brushing the tubes with a Staticmaster Brush, Model 1C200, Nuclear
Products Company, El Monte, California.
Experimentally-observed permeation rates were obtained statistically
as slopes of the linear regression line fitted to the weight versus
time data assuming the first-order model
11 Q i O V _t_ e~~
M w /v " Pf> """ Pi A + E
M y/x 0 1
where u /x = mean weight of permeation tube at time X
y = weight of permeation tube
X = time
BQ = intercept
$1 = slope (permeation rate)
e = the increment by which any individual y may fall
off the regression line.
The experimental permeation rate is defined as
Permeation Rate (ng/min) = bj ± sb tj_a/2 (k-2)
i
where bj = estimated permeation rate, ng/min
k = number of data points
sb = standard error of the estimated permeation
* rate bj.
and ti_a/2 (k-2) = Student t with k-2 degrees of freedom
at significance level a (two-sided test)
This is for a confidence interval of 100 (l-a)% For this study, a
was chosen to be 0.05 to give a 95 percent confidence interval around
the true average permeation rate.
Sample Valves: Teflon 6-port rotary valves, Model 50,
were purchased from Rheodyne, Incorporated,
Berkeley, California, and a 10-port
sliding valve of unknown origin was
provided by QAB.
Dilution System: All-Teflon system employing the recommended
Komhyr A-150 pumps (Science Pump Corporation,
Camden, New Jersey) and housed in an
oven maintained at 120°C as specified
in Sections 12.1.2 and 12.1.2.1.
-------
GC Columns;
Method 15:
Special silica gel was purchased from
Tracer, Inc., Austin, Texas, and was
gravity packed into 6-ft x 1/8-in sections
of FEP tubing, glass tubing and nickel
tubing. Some columns were prepared
using silica gel which had been acid
washed according to Thornsberry. This
was done by placing 10 g of the silica
gel in a medium porosity fritted glass
filter and washing with 30 mL of concentrated
hydrochloric acid, 90 mL of distilled
water, and 90 mL of acetone in that
order. The flow rate was approximately
5-10 mL/min. After air drying, the
substrate was packed into the column
and conditioned overnight in the chromatograph
at 150°C and 50-60 mL/min nitrogen carrier
flow through the column.
A 36-ft x 1/8-in Stevens4'5 column was
prepared according to the method of
Pecsar and Hartman. This FEP Teflon
column typically has a 9 percent (Wt/Wt)
loading of a mixture composed of 96
percent polyphenyl ether PMPE-SR and
4 percent orthophosphoric acid on 40/60
mesh Teflon powder (Chromosorb T).
This column separates HgS, MeSH, and
DMS. For the analysis of DMDS a 10-
ft x 1/8-in FEP Teflon column filled
with Chromosorb T was flow-coated with
Triton X-305.
A commercial version of the Stevens column was later purchased
from Supelco, Inc., Bellefonte, Pennsylvania.
Calibration gas cylinders were purchased from Scott Specialty
Gases, Plumsteadville, Pennsylvania. The cylinders were Scott Aculife"
of treated aluminum.
GC Columns;
Method 16:
Vendor analyses are as follows:
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Designation
Cylinder
1A
Method 15<
2A
3A
4A
IB
Msthod 16<
2B
3B
4B
Compound
fcos
f "2s
1CS2
'cos
H2S
CS0
COS
H2S
.CS,
COS
H2S
Lcs2
H2S
MeSH
DMS
DMDS
H2S
MeSH
DMS
DMDS
H2S
MeSH
DMS
DMDS
*
'H2S
MeSH
DMS
DMDS
Concentration,
0.201
0.709
0.619
1.02
2.36
1.54
7.61
2.46
5.14
2.69
11.1
6.14
0.742
0.574
0.619
0.866
0.925
1.96
1.93
1.38
4.00
6.01
4.76
2.83
5.84
9.99
7.39
5.52
Cylinder stability studies were performed using the originally-recommended
columns and either an FPD or Hall 700A ECD for detection.
8
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SECTION 4
RESULTS AND DISCUSSION
FLAME PHOTOMETRIC DETECTOR
The performance of the flame photometric detector of the Brody
and Chaney design has been well documented.6-12 Its main values lie
in its high sensitivity-and high selectivity toward sulfur compounds.
It does have several troublesome disadvantages. A limited dynamic
range forces careful selection of sample sizes and/or the use of a
dilution system. For example, it was found that when a slow-eluting
compound of =4 ppm and H2$ at ^7 ppm were together in the same gas
stream, a sample size that would allow the slow-eluting material to
be quantitated at an attenuation of IX would cause the H2$ peak to
be off-scale at the least sensitive attentuation, 1024X.
It was suggested^ that, in cases where actual emissions are
found to be outside the ranges of concentrations used for instrument
calibration, the substitution of a different size sample loop (either
smaller or larger) could be used to bring the sample within range.
By application of the square or square -root, as appropriate, of the
sample loop volume ratio to the results obtained with the substitute
loop, the actual concentrations could then be calculated. This would,
in theory, obviate the use of a:'dl'Tutidn system to allow high concentrations
to be quantitated. To test this theory, several concentrations of
H2S, COS, and C$2 were generated and analyzed by Method 15 using two
different sample loops of 2.1 mL and 0.6 mL. Log-log plots of peak
area versus concentration (ppm) are shown in Figures 1-3. As an example,
consider the case where a 10.0 ppm concentration of h^S is analyzed
using each of the two loops. With the smaller loop, an area of 3.5
x lO5* area units is obtained. Assuming a quadratic response the calculated
area for the 2.1-mL,loop would be (2.1/0.6)2(.3.5 x,105) = 4.29 x 106
area units, corresponding to 13.5 ppm (35 percent high). The experimental
area of the peak was found to be 2.9 'x 10^ area units. Even larger
errors result when this metlfod is applied to COS (55 percent high)
and C$2 (95 percent high). The point is clear; assumption of a quadratic
response of the FPD to these compounds may lead to large errors.
-------
TO3
H2S, ppm
FIGURE 1. H,S CALIBRATION CURVES AT TWO VOLUMES
10
-------
106 --
§
c
D
s
s
D)
0)
£ 105 "
(D
(0
C
o
a
cc
Q
a.
104 --
103
0.5 1 5
COS,ppm
FIGURE 2. COS CALIBRATION CURVES AT TWO VOLUMES
11
-------
107'-
106"
(0
*^
'c
D
o
+•*
2
O)'
0
0)
c 105
o
a
(0
0}
CE
Q
a.
LL
104
2.1 mLloop
0.6 mL loop
0.5 1 5
CS2, ppm
10
FIGURES. CS2 CALIBRATION CURVES AT TWO VOLUMES
12
-------
Nonlinearity of response and varying responses to different sulfur-
containing species are drawbacks that must be recognized when using
the FPD.
The nonlinearity of response of the FPD toward sulfur-containing
species is sometimes treated by use of a "linearizer" which takes
the square root of the signal. Extrapolations of calibration lines
generated with such a device may result in large errors (up to 400
percent) being incorporated in the measurement. ^4
Greer and Bydalek10 characterized the response of the Mel par
FPD for H2$ and $03 and concluded that it could be defined by the
general equation
2
R =
where K = equilibrium constant for the reaction S + S |. S2
S and S2 = masses of their respective materials in the flame
kj, k£ and a = constants which may be determined experimentally.
They state that the most simple theoretically sound calibration curve
is a log-log plot of detector response versus sulfur mass. This gives
a straight line with a slope of 2 up to the point of self-absorption,
corresponding to a range of 0 to about 100 ng of sulfur. Other workers
have shown that a plot of response versus sulfur compound concentration
is linear up to 1 ppm, at which point a negative deviation is observed. $
Regression lines were calculated for the plot of peak area versus
log concentration (ppm) for ^S, COS and C$2 over the entire range
which could be conveniently generated with the described permeation
tube system. The data appear in Tables 1-3. Assuming the simple
relationship A = K[S]n to hold, where A = peak area and [S] = sulfur
gas concentration in ppm, values for the exponent n and the proportionality
constants K were determined for each compound using this equation
in logarithmic form. From log A = log K + n log [S], n was obtained
as the slope of the linear regression line fitted to the log area
vers.us log [S] data for each compound. Duplicate or triplicate analyses
of each concentration of each sulfur compound were used to determine
the regression lines. For COS, n = 1.77 with a correlation coefficient
of 0.995. For ^S and C$2, the fits were similar with n = 1.74 (correlation
coefficient of 0.995) and 1.72 (correlation coefficient of 0.997),
respectively. These values were obtained over a limited range, however,
and attempts to use the values outside this range would not be advised.
In general, we found that the actual shape of experimental log-
log calibration lines was slightly curvilinear upward (see Figures
13
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TABLE 1. FPD RESPONSE TO H2S CONCENTRATION
[H2S], ppm
0.6
H
1.0
M
2.0
II
3.0
M
4.0
M
5.0
II
Slope = 1.74
Intercept =
Correlation
[COS], ppm
0.6
11
0.9
It
1.9
M
2.7
H
3.7
H
4.7
H
Log [H2S]
-0.22185
M
0.00000
II
0.30103
H
0.47712
n
0.60206
n
0.69897
II
4.91
Coefficient = 0.995
TABLE 2. FPD RESPONSE
Log [COS]
-0.22185
II
-0.04576
II
0.27875
n
0.43136
n
0.56820
n
0.67210
n
Peak Area
36943
34881
78906
77666
245568
247294
480303
490872
810502
833298
1706374
1711639
TO COS CONCENTRATION
Peak Area
27271
25583
54150
53481
161630
163584
340092
341852
564883
564333
1181471
1189395
Log Area
4.56753
4.56259
4.89711
4.89023
5.39017
5.39321
5.68152
5.69097
5.90875
5.92080
6.23207
6.23341
•
Log Area
4.43570
4.40795
4.73360
4.72820
5.20852
5.21374
5.53160
5.53384
5.75196
5.75154
6.07242
6.07523
Slope = 1.77
Intercept =4.79
Correlation Coefficient = 0.995
14
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TABLE 3. FPD RESPONSE TO CS2 CONCENTRATION
[CSe], ppm
0.35
H
H
0.55
H
n
1.1
n
n
1.6
n
ii
2.3
n
n
3.0
n
Log [CS2]
-0.45593
ti
n
-0.25964
II
II
0.04139
n
n
0.20412
n
n
0.36173
11
II
0.47712
n
Peak Area
33948
34858
35230
83608
82768
80509
265116
271437
275103
474967
488780
486569
767023
781205
799125
1750687
1752852
Log Area
4.53081
4.54230
4.54269
4.92225
4.91786
4.90584
5.42344
5.43367
5.43950
5.67666
5.68911
5.68714
5.88481
5.89277
5.90261
6.24321
6.24375
Slope = 1.72
Intercept =5.34
Correlation Coefficient = 0.997
15
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2 and 3) with increasing concentration. This can be explained by
the observation that varying amounts of the TRS compounds are adsorbed
by the chromatographic system, mainly the column, packing and detector.
It has been reported6 that detector response to H£S was reduced by
an order of magnitude when a five-foot section of empty 1/8-in Teflon
tubing was placed between the sample valve and the GC column. If
the amount adsorbed is relatively constant, it follows that the initial
fraction adsorbed becomes increasingly greater as the concentration
decreases.
This loss of TRS compounds (in particular H2S) is the main contributor
to inaccuracy and imprecision in the two methods. It is necessary
to passivate a fresh system (the sample loop, column, detector and
connecting tubing) by repeated injections of sample gas or by several
injections of a more concentrated mixture of a sulfur gas or gases.
While this is necessary to attain reasonable repeatability, its effect
is not lasting, and repassivation is required after a few hours.
This observation is consistent with an adsorption-desorption mechanism
in which sites in the system are rapidly tied up by reactive sulfur
species, and then in a much slower process, reactivation occurs, presumably
due to the sweeping action of the carrier gas.
Loss of reactive materials during attempted analysis of trace
amounts is well known and can be a major problem to the chromatographer.
In the methods studied, several precautions should be taken to minimize
quantisation errors introduced by the adsorption-desorption phenomenon.
First, use of stainless steel in contact with the sample is to be
avoided. Some workers15 have used stainless steel tubing for GC columns
in the analysis of sulfur gases in hydrocarbon streams, but concentration
levels were slightly higher and losses from long sample lines were
not a problem in this case. Substitution of Teflon components is
not a panacea, for the "cold flow" characteristics of the polymer
may cause leaks (vide supra). The current studies were carried out
with Teflon rotary six-port valves which had an upper temperature
limit of 60°C, according to the manufacturer. Even at ambient temperature,
periodic tightening of the valve fittings was required to stop leaks.
Conversations with representatives of the kraft paper industries in
the U.S. and in Canada revealed that sample valves of Carpenter 20
and, more recently, Hastalloy C are used in the analysis of low levels
of TRS compounds with entirely satisfactory results. A representative
of Valco, Inc. (Houston, Texas), a major supplier of valves for gas
and liquid chromatography, claims that rotary valves of Hastalloy
C are in widespread use by the petroleum industry for the ppm and
sub-ppm analysis of sulfur gases. Such valves are claimed to be as
"inert" as Teflon but have a much higher temperature limit and no
leak problems.
16
-------
Some FPD detectors may be modified to reduce sample losses.
A stainless steel jet was supplied with the Melpar FPD in our Hewlett-
Packard GC. When the metal jet was replaced with a glass jet (purchased
from Tracer Instruments and supplied with the Melpar FPD in their
chromatographs), peak growth was minimized. Figures 4-6 illustrate
the improvement realized.
Although not tested, it is conceivable that the presence of a
low level of, say, H£$ in the carrier gas would continually passivate
the system at a small loss in dynamic range due to background. This
Jow level could be generated by passing the carrier gas over a low-
rate permeation tube.
Greatest precision would be obtained when samples and calibration
gases of the same approximate concentrations are injected at even
intervals under steady chromatographic conditions. A continuous GC
monitor with a relatively fast analysis time (=10 min) would appear
to be the most reasonable way to maximize both precision and accuracy
in the analysis of the subject compounds at the low-ppm level.
HALL 700A ELECTROLYTIC CONDUCTIVITY DETECTOR
A detector capable of being operated in a sulfur-specific mode
was used in these laboratories in side-by-side comparisons with the
FPD. This detector, the Hall 700A Electrolytic Conductivity Detector,
was found to be the equal of the FPD with respect to sensitivity and
superior in its independence from response quenching by the presence
of hydrocarbons. In addition, its response was found to be linear
over the range of concentrations of COS, H£S and C$2 generable with
the available permeation tubes (typical calibration curves shown in
Figure 7 with calibration data listed in Tables 4, 5 and 6). Compare
the responses of the FPD and the Hall ECD to varying amounts of the
sulfur compounds of Method 15. Conditions are listed in Table 7 and
the chromatograms shown in Figure 8. Traces 1 and 2 show the abrupt
change in peak size which occurs with the FPD detector when the sample
masses are reduced by 72 percent. Traces 3 and 4 show the more nearly
linear response of the Hall ECD under the same conditions and display
the excellent peak shapes attained.
In the sulfur mode, the Hall detector converts sulfur-containing
species to $03 by air oxidation in a heated nickel tube reactor at
750-1000°C. The reactor effluent is scrubbed and passed into the
conductivity cell containing a flow of methanol (0.5-0.7 mL/min) as
electrolyte. The conductivity change is measured, and the electrolyte
is passed through an ion exchange cartridge containing 50 percent
17
-------
100 r
£
>^.
o
Q.
•5
With Metal Jet
With Glass Jet
40 -
3 4
Injection Number
FIGURE4. H2S PEAK GROWTH WITH GLASS AND WITH METAL FPD JETS
2345
Injection Number
FIGURE 5. COS PEAK GROWTH WITH GLASS AND WITH METAL FPD JETS
.£
With Metal Jet
With Glass Jet
O-
FIGURE 6. CS2 PEAK GROWTH WITH GLASS AND WITH METAL FPD JETS
18
-------
E
E
H
I
g
LLJ
I
Slope
Intercept
Correlation
1
CONCENTRATION, PPM
FIGURE 7. TYPICAL CALIBRATION CURVES WITH HALL 700A ECD
-------
TABLE 4- HALL 700A ECD RESPONSE TO COS CONCENTRATION
[COS], ppm
Peak Height, mm
0.5
0.6
0.9
1.2
2.0
3.5
7.6
49
61
91
115
172
297
632
TABLE 5. HALL 700A ECD RESPONSE TO H2S CONCENTRATION
[HgS], ppm
0.9
1.0
1.2
2.0
3.0
5.8
11.8
Peak Height, mm
100
121
170
227
329
538
1080
TABLE 6. HALL 700A ECD RESPONSE TO CS2 CONCENTRATION
[C$2], ppm
0.3
0.4
0.5
0.8
1.1
2.1
4.6
Peak Height, mm
34
42
59
82
128
220
465
20
-------
TABLE 7. COMPARISON OF FPD AND HALL 700A ECO RESPONSES
Compound
COS
H2S
cs2
Concentration,
ppm
3.1
4.8
1.8
ng S in 2.1 mL
8.52
13.19
9.89
ng S in 0.6
2.43
3.77
2.83
mL
Column:
Oven temperature:
Carrier gas:
Recorder Speed:
6-ft x 1/8-in FEP Teflon filled with acid-washed,
deactivated silica gel.
50°C
N2 at 20 mL/min
0.5 in/min
Results
Peak Heights (mm)
of 2.1 mL sample
Peak Heights (mm)
of 0.6 mL sample
Compound
COS
H2S
CSo
FPD
47.5
216.5
75.0
Hall ECD
144.5
218.0
119.0
FPD
5.5
20.5
7.5
Hall ECD
60
85
39
21
-------
FPD
HALL700AECD
a
o
o
a
o
o
E
CN
a.
o
o
E
ID
O
§
X'
TRACE 1
Q.
O
O
E
CD
d
TRACE 2
TRACES
TRACE4
FIGURE 8. FPD AND HALL 700A ECD RESPONSES
22
-------
IRN-77 and 50 percent IRN-150 and is then recycled to the cell. A
diagram of the reactor appears as Figure 9.
Tracor claims no interferences result from the coelution of hydrocarbons
with sulfur compounds. Some maintenance is required by the Hall ECD,
because the electrolyte reservoir must be periodically topped up and'
the ion exchange column replaced from time to time. These chores
are minor; however, it was necessary to replace the nickel reactor
tube on our test instrument, a job requiring several hours of downtime.
It is felt that the Hall ECD should be strongly considered as
an alternative detector in Methods 15 and 16 and that a field test
comparing it to the FPD is called for.
COLUMNS AND SYSTEMS
All column materials evaluated in this study were packed in 1/8-in
(3.175 mm) FEP Teflon tubing. To test the effect of replacing the
Teflon by other "inert" materials, three 2-m x 2-mm ID columns, one
FEP Teflon, one glass, and one nickel, were filled with acid-washed
Tracor Special Silica Gel and used for the analysis of a permeation
tube-generated blend of H2$ (0.90 ppm), COS (0.48 ppm) and C$2 (0.35
ppm). A sample loop volume of 2.1 ml determined that the masses of
the sulfur compounds were 2.6, 2.5, and 2.3 ng per injection, for
H2S, COS, and C$2, respectively.
Each column was "passivated" by repeated injections of the gas
blend, six replicate analyses were performed, and the average peak
areas were calculated. As can be seen in Figure 10, the appearances
of the chromatograms obtained with the Teflon and glass columns are
similar. Some loss of COS and ^S is observed with the glass column
with peak areas of 75 percent and 79 percent, respectively, of the
Teflon column results. The C$2 peak was higher, and its integration
was 109 percent of the Teflon column results. This latter result
may be an artifact of the differing peak shapes obtained on the glass
column. Peak retention times obtained on the nickel column were essentially
identical to those of the Teflon, but some loss of all compounds was
observed with the nickel column. Only 35 percent of the H2S, 85 percent
of the COS, and 83 percent of the C$2 peak areas (relative to the
Teflon column) were observed. These results do not necessarily rule
out the use of nickel tubing for the columns, for losses on the column
depend upon concentration or at least upon mass flux of sulfur-containing
material. However, if losses in the sample line are appreciable,
then the added losses on the column and the nonlinearity of the FPD
detector may, in combination, reduce the apparent sensitivity of the
method(s) to an unacceptable level.
23
-------
SCRUBBER
\
SOLVENT INLET .
STAINLESS STEEL
BACK FERRULE
STAINLESS STEEL
FRONT FERRULE *
GRAPHITE FERRULE
STAINLESS STEEL
BACK FERRULE
FIGURES. HALL700A ECD REACTOR-CONDUCTIVITY CELL
(SULFUR AND NITROGEN MODES)
24
-------
FEP TEFLON
GLASS
NICKEL
ro
01
2m x 2mm ID columns containing
Tracer Special Silica Gel
Column Temperature: 50°
N2 Carrier flow: 20 mL/min
Sample volume: 2.1 mL (loop)
Attenuation: x4
Compounds (order of elution)
COS (0.48 ppm, 1.32 ng S)
H2S (0.90 ppm, 2.47 ng S)
CS2 (0.35 ppm, 1.92ngS)
FIGURE 10. EFFECT OF TUBING MATERIAL ON PEAK SHAPES
-------
The recommended silica gel column was prepared using Tracer Special
Silica Gel. Deactigel,® a deactivated silica gel appearing in Catalog
22 of Applied Science Laboratories, Inc., State College, Pennsylvania,
could not be purchased. A sales representative said the material
had been withdrawn from the market because batch-to-batch performance
was erratic. Two samples of the Tracer material were obtained, and
columns constructed from the substrate "as received" were unable to
separate COS and I^S at temperatures above ambient (25°C). The effect
of this is clear; such a column could not be used in the field during
warm weather conditions except when housed in a cryogenic container.
However, if the silica gel was acid-washed with concentrated hydrochloric
acid and then with water, it was capable of baseline separation of
COS and H2S at 50°C or slightly above3 (see Section 3, "Experimental").
A deactivated silica for this analysis is offered commercially by
Supelco, Inc. but was not evaluated.
To determine the possible interference of C02 in a Method 15
analysis, a dilution gas mixture of 10 percent C0£ in Ng was substituted
for the nitrogen flow over the permeation tubes, and low levels (1-2
ppm) of COS, H2S, and C$2 were generated and analyzed. Using the
silica gel column, no interference by C02 was observed.
Separation of the subject compounds could also be effected with
a 14-in x 1/8-in Teflon column filled with Chromosorb 102. To achieve
a reasonable analysis time and C$2 peak shape, it was necessary to
use a temperature program. With a program of 45°C (2 min hold) to 130°C
at 32°/min (2 min hold), the following retention times were obtained:
H2S - 0.95 min; COS - 1.44 min; and C$2 - 4.90 min. The necessity
to use a temperature program would seem to speak against the use of
this column for two reasons. First, reproducible retention times
are difficult to obtain. This in turn affects peak shape and introduces
errors if peak heights are being used for quantisation. Second, leaks
at the points of column attachment were a frequent problem and could
be attributed to "cold flow" of the thermoplastic Teflon tubing at
elevated temperatures.
A specially-treated Porapak QS column16 also separated the Method
15 compounds, but it, too, had to be temperature programmed and suffered
from the same drawbacks as the Chromosorb 102 column. According to
de Souza, et al.,16 this column is capable of separating -J^S, COS,
S02, MeSH, DMS, and DMDS using a temperature program from 30° to 210°C.
Our conclusion, based upon the above results and others (vide
infra), is that the example silica gel column is the column of choice
for Method 15 but may require an acid wash to obtain the required
performance.
26
-------
The above-mentioned Porapak QS column (available from Supelco
as Supelpak-S) was found to separate the TRS compounds of Method 16,
but again, it is necessary to use a temperature program. In our instrument,
the baseline would drift off scale at low attenuation when the upper
temperatures of the program were reached. Attempts to correct this
failed, and a factory representative could offer no solution.
The Stevens4*5 polyphenyl ether/HsPCty column was prepared according
to the method of Pecsar and Hartman.6 Resolution of ^S, MeSH, and
DMS was excellent, and in fact a 12-foot section could be used to
resolve all four TRS materials. Because of the broad shape of the
DMDS peak, <1 ppm concentrations of this relatively nonvolatile compound
could not be observed.
Neither this column nor a similar, commercially-prepared column
could separate COS and I^S. This fact alone could disqualify its
use, for it has been reported by de Souza17 and others18 that COS
has been found in recovery boiler stacks and lime kilns. COS is nonodori-
ferous and is not a TRS compound. If not separated, its presence
could erroneously show a process to be out of compliance.
When 10 percent C02 was added to a low-level (0.5-2 ppm) synthetic
blend of the four TRS compounds, no change in the analysis occurred
compared to those without C02-
At least four systems are known which can be used to analyze
for TRS compounds isothermally and with a single injection on a single
instrument. They have been reported by de Souza17 of the Pulp and
Paper Research Institute of Canada and by Jain19 of the National Council
of the Paper Industry for Air and Stream Improvement, Inc. A continuous
monitor offered by Bendix Environmental and Process Instruments and
one under development by Tracor make the same claims. It was beyond
the scope of the program to evaluate these systems in the laboratory.
From information that is available, all systems obviate the need for
two chromatographs to perform Method 16. The Tracor system does not
separate MeSH, DMS, and DMDS but quantitates them together using a
linearized FPD. The de Souza Automatic GC Monitor quantitates H2S,
COS, S02, MeSH, DMS, DMDS, and TRS using three columns in three different
ovens. The Bendix analyzer claims to separate all TRS compounds from
COS and to have a superior sample-handling system. Again, it is felt
that a continuous-type analyzer would be best from the standpoints
of accuracy and precision.
PERMEATION TUBE STUDY
Time required to reach permeation rate equilibrium after a temperature
27
-------
change and the long-term rate stabilities of a number of O'Keeffe-
type permeation tubes have been investigated by Williams.20 Compounds
studied included H2S, MeSH, and DMS. He concluded that rates for
MeSH and DMS were stable within one percent over periods from 7-17
days. H2S permeation rates decreased by three percent over 20 days,
but insufficient data were available to predict a continued decrease.
A personal communication with the author revealed that no further
studies had been carried out.
Our three-month study of permeation tubes containing each of
the Method 15 and Method 16 compounds showed the rates to remain unchanged
(within two percent) over the entire period (Figures 11-16). Of interest
is the fact that the experimentally-determined rates agreed well with
the vendor-certified rates in three cases (C$2, H2$, and DMS), fairly
well in one (MeSH) and poorly in two others (COS and DMDS). The comparison
of rates is given in Table 8.
Experimentally determined values were low in all cases, ranging
from 99.8 percent to 79.5 percent of the certified rates. The uniformly
low nature of the results is likely due to a small temperature difference
between the baths in which the two sets of determinations were made,
but a temperature difference does not explain the range of discrepancies
found. Since the rates were determined after approximately one year
of use, it cannot be stated that the certified rates were in error.
However, we feel that it would be prudent for purchasers of tubes
to verify experimentally their permeation rates.
GAS CYLINDER STABILITY STUDIES
Table 9 contains the vendor analyses and our periodic analyses
of the four cylinders (1A-4A) containing Method 15 compounds. The
same information for the four cylinders containing the Method 16 compounds
is given in Table 10. Immediately apparent is the fact that several
of the mixtures contained one or more components in a concentration
too high to be conveniently analyzed with our available permeation
tube system. The reason given by the supplier for the high values
was that it was necessary to make blends of concentrations higher
than those specified so that the inevitable loss of some of the reactive
materials (on the inner walls or by reaction) could be allowed for.
If the amount of the loss was underestimated, a high value resulted.
Rather than return the cylinders, it was decided to begin the stability
study with the materials as received.
Tables 9 and 10 reveal a considerable amount of scatter in the
data. This is attributed to the inherent lack of precision and accuracy
28
-------
ro
10
11.00
10.99 -
w
E
(0
O)
10.91
1
H2S PERMEATION RATE
699±2.8ng/min
30.0° C
8
10
234567
Time, weeks
FIGURE 11. GRAVIMETRIC CALIBRATION OF H2S PERMEATION DEVICE
12
-------
co
o
40.98 -•
40.97 --
CO
o> 40.96
o
_o
40.95 --
c
.0
§ 40.94
o>
CO
O
O
£
O)
'5
40.93 -•
40.92 --
40.91 --
40.90
COS PERMEATION RATE =
628±2.8ng/min
30.0° C
Time, weeks
FIGURE 12. GRAVIMETRIC CALIBRATION OF COS PERMEATION DEVICE
-------
4.94
CS2 PERMEATION RATE =
599 ±9.1 ng/min
30.0° C
8
10
11
12
34567
Time, weeks
FIGURE 13. GRAVIMETRIC CALIBRATION OF CS2 PERMEATION DEVICE
-------
co
K>
V)
E 4.53
2
O)
03
.2 4.52
0)
Q
.2 4-51
CD
(D
§ 4.50 4-
o.
I
w 4.49 --
D)
'5 4.48
4.47
MeSH PERMEATION RATE =
352±4.9ng/min
30.0° C
1234
H H
5 6 7 8 9 10 11 12
Time, weeks
FIGURE 14. GRAVIMETRIC CALIBRATION OF MeSH PERMEATION DEVICE
-------
8.72
CO
DMS PERMEATION RATE
506±2.5ng/min
30.0° C
8.65
1234 56 7
Time, weeks
FIGURE 15. GRAVIMETRIC CALIBRATION OF DMS PERMEATION DEVICE
-------
co
CO
E
£ 12.495
O)
0)
'5 12.490
0)
Q
c
*j 12.485 t
1
a!. 12.480 --
CO
Q
Q 12.475
O)
12.470
4-
4-
4-
4-
4-
DMDS PERMEATION RATE
93 ± 1.5ng/min
30.0° C
H h
123456 7 8 9 10 11 12
Time, Weeks
FIGURE 16. GRAVIMETRIC CALIBRATION OF DMDS PERMEATION DEVICE
-------
TABLE 8. COMPARISON OF EXPERIMENTALLY-DETERMINED AND
VENDOR-CERTIFIED PERMEATION RATES
Compound
H2S
COS
CS2
MeSH
DMS
DMDS
Certified
Rate
690+2%
790+5%
600+2%
380+2%
520+2%
109+5%
Fxpe rl mental
Rate
669+0.4%
628+0.5%
599+1.5%
352+1.4%
506+0.5%
93+1.6%
% of Certi
Value
97.0
79.5
99.8
92.6
97.3
85.3
fw •- r ' • ' • • *
fied
A*
- 3.0
-20.5
- 0.2
- 7.4
- 2.7
-14.7
A% = - 8.1%
35
-------
TABLE 9. GAS CYLINDER STABILITY STUDY - METHOD 15
CO
en
Cyl inder
Designation
1A
2A
3A i
(
4A <
Compound 12-15-79a
CCOS 0.201
H2S 0.709
CS2 0.619
rCOS 1.02
H2S 2.36
CS2 1.54
fCOS 7.61
H2S 2.46
VCS2 5.14
(COS 2.69
H2S 11.1
j:S2 6.14
1-26-79
0.0
0.4
0.7
1.0
2.1
1.9
3.2
3.8
7b
1.30
9.1
gb
Date of
3-7-79
0.0
b
0.55
0.70
1.90
1.55
3.56
4.20
6.1b
c
c
c
Analysis (Cone, in ppm)
3-16-79 4-10-79
0.0 0.0
0.10
0.65 0.82
0.67 0.62
2.25 2.95
1.75 1.90
3.95 3.85
4.85 5.90
6.4b 7b
c c
c c
c c
5-11-79
0.0
0.15
0.64
0.59
2.67
1.58
4.25
6.62
6b
c
c
c
a. Final vendor analysis before shipping
b. Outside calibration range - values obtained by extrapolation
c. Contents of cylinder lost by leak at valve
-------
TABLE 10. GAS CYLINDER STABILITY STUDY - METHOD 16
CO
Cylinder
Designation Compound
IB
fH2S
MeSH
DMS
J)MDS
noo
2B
in j
3B *
4R 4
MeSH
DMS
J)MDS
fH2S
MeSH
DMS
[JDMDS
fH2S
MeSH
DMS
DMDS
V.
Date of Analysis (Cone. 1n ppm)
12-15-78*
0.742
0.574
0.430
0.866
0.925
1.96
1.93
1.38
4.00
6.01
4.76
2.83
5.84
9.99
7.39
5.52
1-30-79
0.20
0.75
0.70
1.35
0.45
1.52
3.25
2.70
3.25
5.25
7.6b
4.90
c
c
c
2-28-79
0.20
0.68
0.45
0.93
0.50
1.50
2.15
1.87
3.15
6.00
6.9b
3.8b
4.05
c
6.5b
6.5b
3-12-79 3-28-79
-------
in the methods owing to the adsorption-desorption phenomenon described
above. The correlation coefficients are used to determine if a significant
slope exists, which is an indication of a change in the concentration
over time. The required correlation coefficients for significance
at the 5-percent level are 0.878 and 0.811 for samples of size 5 and
6, respectively.
Significant correlations were obtained for ^S and COS in cylinder
3A, for COS in cylinder 2A, MeSH in cylinder 2B, and for DMS in cylinder
3B. In cylinder 3A, there was an increase in h^S concentration from
3.8 to 6.62 ppm, giving an average rate of 0.03 ppm per day. The
COS concentration also increased at an average rate (slope) of 0.01
ppm per day, from 3.2 to 4.25 ppm. There was no significant slope
on the C$2 determinations over time, but the scatter in the results
indicates that analytical variability would preclude the determination
of a trend based upon such a limited amount of data.
The concentration of COS in cylinder 2A decreased at an average
rate of 0.004 ppm per day over the course of the study. There was
an increasing trend in the HgS concentration and a decreasing trend
in the C$2 which were not significant.
The decreasing trend for MeSH in cylinder 2B was significant
at a rate of 0.002 ppm per day, and H2S, DMS and DMDS also showed
decreased amounts relative to the initial analysis. In the other
analyses, however, there was considerable scatter among the points
away from the regression line, and correlation was not adequate to
say a trend existed. However, the overall impression was that the
contents were lower after time. In cylinder 3B, DMS decreased significantly
at a rate of 0.02 ppm per day, but all other components could be considered
uniform over the time period studied.
No consistent trend appeared among the cylinders for the behavior
of the compounds under study. In all four cylinders of mixture A,
the concentration of COS at time zero was lower than the vendor analysis,
but in two cases it continued to decrease while in one case it increased
significantly. Similar behavior was exhibited among analyses for
the other two compounds in this mixture. The concentrations in mixture
B also behaved erratically, with higher and lower values than the
vendor analysis and increasing and decreasing trends. The apparent
conclusion is that the concentrations are not verifiable as reported
by the vendor, either due to analytical methodology or to changes
in concentration with time, and cannot be assumed to be stable upon
holding.
38
-------
DILUTION SYSTEM
A dilution system was constructed as per Section 5.2 of Federal
Register 41. pp. 43871, October 4, 1976. Figure 17 is a photograph
of the system without the oven top, viewed from above. Not shown
is a baffle plate which was mounted near the fan to aid circulation.
Results obtained with this system were erratic and were traced to
the Komhyr A-150 "constant flow rate" pumps. When dilution air at
1350 mL/min was introduced downstream of the pump, the attendant back
pressure caused the pump to leak at its head. The design of the head
is such that a leak of this sort is unavoidable. A conversation with
the supplier of the A-150 revealed that they were aware of this problem
but that the pump was designed to operate against a small constant
pressure and not in the system described.
A prototype single-stage dilution system was fabricated which
gave consistent dilutions when used in the laboratory analysis of
synthetic blends. Flow rates of both the sample gas and the dilution
air were regulated by passing each through appropriate lengths of
capillary stainless steel tubing while controlling the upstream pressures.
The effluents were combined in a stainless steel tubing "tee" leading
to 1/4-in Teflon tubing. Possible scavenging effects of the metal
parts were tested by analyzing an undiluted blend of low-ppm concentration
H£S and then comparing the results to those obtained while bypassing
the dilution system. Within experimental error, no difference was
observed. It remains to be determined whether such a simple system
could be made to work under field conditions which would require a
good filtration device to prevent partial or total plugging of the
capillary system.
FIELD STUDIES
Field studies involving Method 16 techniques and equipment were
begun in September 1979 by Harmon Engineering & Testing of Auburn,
Alabama. Under a separate contract with the QAD, Harmon has been
given the responsibility of securing a suitable kraft pulp mill for
the testing. Southwest Research Institute is to collaborate in this
study to the extent that we will furnish a Tracer Model 560 gas chromatograph
equipped with both a Melpar FPD and a Hall Electrolytic Conductivity
Detector. This will allow a side-by-side comparison of the two under
field conditions. Cylinder gases containing the four TRS compounds
will be forwarded to Harmon to facilitate pretest studies and to possibly
be used at the kraft mill site. In addition, technical support in
the field will be provided.
39
-------
FIGURE 17. TOP VIEW OF OVEN CONTAINING TWO-STAGE DILUTION SYSTEM
-------
REFEREMCES
1. A. E. O'Keeffe and G. C. Ortman, Anal. Chem., 38, 760 (1966).
2. F. P. Scaringelli, A. E. O'Keeffe, E. Rosenberg andJ. P. Bell,
ibid., 42, 871 (1970).
3. W. L. Thornsberry, Jr., ibid., 43_, 452 (1971).
4. R. K. Stevens, et al., Environ. Sci. and Techno!., 3_, 652 (1969).
5, R. K. Stevens and A. E. O'Keeffe, Anal. Chem., 42_, 143A (1970).
6. R. E. Pecsar and C. H. Hartman, J. Chromatog. Sci.» 11, 492
(1973). ~
7. S. S. Brody and J. E. Chaney, J_. Gas Chromatog.. 4_, 42 (1966).
8. B. H. Devonald, R. S. Serenius and A. D. Mclntyre, Paper presented
at the 6th Air and Stream Improvement Conference, Quebec, April
13-15, 1971.
9. R. K. Stevens, A. E. O'Keeffe and G. C. Ortman, Environ. Sci.
and Technol., 3_, 652 (1969).
10. D. G. Greer and T. J. Bydalek, ibid., T_, 153 (1973).
11. S. 0. Farwell and R. A. Rasmussen, J_. Chromatog. Sci., 14_, 224
(1976).
12. A. Attar, R. Forgey, J. Horn and W. H. Corcoran, ibid., 15_,
222 (1977).
13. Dr. Bruce Ferguson, Harmon Engineering Co., Auburn, Alabama,
private communication.
14. C. H. Burnett, D. F. Adams and S. 0. Farwell, J_. Chromatog.
Sci., 1£, 230 (1977).
15. C. D. Pearson and W. J. Hines, Anal. Chem.. 49_, 123 (1977).
16. T.L.C. de Souza, D. C. Lane and S. P. Bhatia, Anal. Chem.. 47^,
543 (1975).
41
-------
17. T.L.C. de Souza, R. A. Wostradowski, R. Poole, 0. Vadas, S. P. Bhatia
and S. Prahacs, Pulp and Paper Canada, 79_, 242 (1978).
18. Private communication with Jim Nelsen of Bendix Environmental
and Process Instruments Division of the Bendix Corporation.
19. A. Jain, Atmospheric Quality Improvement Technical Bulletin
No. 81, Appendix F, October 1975.
20. D. L. Williams, "Calibration in Air Monitoring, ASTM STP 598",
American Society for Testing and Materials, 183 (1976).
42
-------
10870
nples of equal sampling time shall
.institute one run. Samples shall be
taken at approximately 1-hour inter-
vals.
. For the purpose of determining
compliance with § 60.104(a)(2).
Method 6 shall be used to determine
the toncentration of SO, and Method
15 sftall be used to determine the con-
centration of H,S and reduced sulfur
compounds.
<1) V Method 6 is used, the proce-
dure outlined in paragraph (c)(2) of
this seition shall be followed except
that each run shall span a minimum
of four consecutive hours of continu-
ous gambling. A number of separate
samples fcay be taken for each run,
provided the total sampling time of
these samples adds up to a minimum
of four consecutive hours. Where more
than one sample is used, the average
SO, concentration for the run shall be
calculated ai the time weighted aver-
age of the SO, concentration for each
sample accorcyng to the formula:
Where:
C,=SO, concentration (or the run.
A'= Number of
Ci,=SO, concentrator! for sample I
Ui=Continuous sampling time of sample i
T^Total continuou^ sampling time of all
ft samples.
(2) If Method 15 Vs used, each run
shall consist of 16 samples taken over
a minimum of three uiours. The sam-
pling point shall be a\ the centroid of
the cross section of the duct if the
cross sectional area isuess than 5 m*
(54 ft*) or at a point nc closer to the
vails than 1 m (39 inches) if the cross
sectional area is 5 m' orynore and the
centroid is more than i meter from
the wall. To insure minimum residence
time for the sample insidi the sample
lines, the sampling rate khall be at
least 3 liters/minute (0.1 ftymin). The
SO: equivalent for each rvbi shall be
calculated as the arithmeticeverage of
the SO, equivalent of each sample
during the run. Reference Method 4
shall be used to determine me mois-
ture content of the gases. The sam-
pling point for Method 4 shall be adja-
cent to the sampling point for Method
15. The sample shall be extracted at a
rate proportional to the gas velocity at
the sampling point. Each runXshall
spar, a minimum of four conseebtive
hours of continuous samplingL A
number of separate samples mat be
taken for each run provided the total
sampling time of these samples aHds
up to a minimum of four consecutive
hours. Where more than one samplr
used, the average moisture content fop
the run shall be calculated as the t:
weighted average of the moisture con!
tent of each sample according to "
formula:
APPENDIX
RULES AND REGULATIONS
•R«.=Proporti(3S^>y volume of water vapor
in.the gas stream for the run.
jv=Number of sam]
£„ = Proportion by volume of water vapor
in the gas stream loathe sample t
*,,=Continuous sampling\jrne for sample
3"«= Total continuous samplingXfme of all
N samples.
(Sec. 114 of the Clean Air Act, as t
[42 U.S.C. 74143).
APPENDIX A — REFERENCE METHODS
7. Appendix A is amended by adding
a new reference method as follows:
METHOD 15. DETERMINATION OF HYDROGEN
SOUIDE. CARBONTL STILFTDE. AKD CAKBON
DISULFZSE EMISSIONS FROM STATIONARY
IKTRO0UCTION
The method described below uses the
principle of gas chroma to graphic separation
and flame photometric detection (FPD).
Since there are many systems or sets of op-
erating conditions that represent usable
methods of determining sulfur emissions, all
systems which employ this principle, but
differ only in details of equipment and oper-
ation. may be used as alternative methods.
provided that the criteria set below are met.
1. Principle and applicability
1.1 Principle. A gas sample is extracted
from the emission source and diluted with
clean dry air. An aliquot of the diluted
sample is then analyzed for hydrogen sul-
fide . carbonyl sulfide (COS), and
carbon disulfide by gas chromatogra-
phic (GO separation and flame photomet-
ric detection (FPD).
1.2 Applicability. This method is applica-
ble for determination of the above sulfur
compounds from tail gas control units of
sulfur recovery plants.
2. Range and sensitivity
2.1 Range. Coupled with a gas chromto-
graphic system utilizing a l-milliliter sample
size, the maximum limit of the PPD for
each sulfur compound is approximately 10
ppm. It may be necessary to dilute gas sam-
ples from sulfur recovery plants hundred-
fold (99:1) resulting in an upper limit of
about 1000 ppm lor eacn compound.
2.2 The minimum detectable concentra-
tion of the FFD is also dependent on sample
size and would be about 0.5 ppm for a 1 ml
sample.
3. Interferences
3.1 Moisture Condensation. Moisture con-
densation in the sample delivery system, the
analytical column, or the FPD burner block
can cause losses or interferences. This po-
tential is eliminated by heating the sample
line, and by conditioning the sample with
dry dilution air to lower its dew point below
the operating temperature of the OC/PPO
analytical system prior to analysis.
3 2 Carbon Monoxide and Carbon Dioxide.
CO and COf have substantial desensitizing
effects on the flame photometric detector
even after 9:1 dilution. (Acceptaole systems
must demonstrate that they have eliminat-
ed this interference by some procedure such
as eluding CO and CO, before any of the
sulfur compounds to be measured.) Compli-
ance with this requirement can be demon-
strated by submitting chromatograms of
calibration gases with and without CO, in
the diluent gas. The COi level should be ap-
proximately 10 percent for the case with
CO, present. The two chromatographs
should show agreement within the precision
limits of section 4.1.
3.3 Elemental Sulfur. The condensation of
sulfur vapor in the sampling line can lead to
eventual coating and even blocicage of the
sample line. This problem can be eliminated
along with the moisture problem by heating
the sample line.
4. Precision
4.1 Calibration Precision. A series of three
consecutive injections of the same calibra-
tion gas. at any dilution, shall produce re-
sults which do not vary by more than ±13
percent from the mean of the three injec-
tions.
4.2 Calibration Drift. The calibration drift
determined from the mean of three injec-
tions made at the beginning and end of any
8-hour period shall not exceed x5 percent.
5. Apparatus
5.1.1 Probe. The probe must be made of
inert material- such as stainless steel or
"glass. It should be designed to incorporate a
filter and to allow calibration gas to enter
the probe at or near the sample entry point.
Any portion of the probe not exposed to the
stack gas must be heated to prevent mois-
ture condensation.
5.1.2 The sample line must be made of
Tenon.'no greater than 1.3 cm (V» in) inside
diameter. All parts from the probe to the di-
lution system must be thermostatically
heated to 120° C.
5.1.3 Sample Pump. The sample pump
shall be a leakless Teflon coated diaphragm
type or equivalent. If the pump is upstream
of the dilution system, the pump head must
be heated to 120- C.
5.2 Dilution System. The dilution system
must be constructed such that all sample
contacts are made of inert material (e.g.
stainless steel or Teflon). It must be heated
to 120" C and be capable of approximately a
9:1 dilution of the sample.
5.3 Gas. Chromatograph. The gas chroma-
topraph must have at least the following
components:
5.3.1 Oven. Capable of maintaining the
separation column at the proper operating
temperature =1* C.
5.3.2 Temperature Gauge. To monitor
column o\-en, detector, and exhaust tem-
perature ±1* C.
5.3.3 Flow System. Gas metering system to
measure sample, fuel, combustion gas. and
carrier gas Hows.
5.3.4 Flame Photometric Detector.
5.3.4.1 Electrometer. Capable of fuU scale
amplification ot linear ranges of 10'" to 10~*
amperes full scale.
5.3.4.2 Power Supply. Capable of deliver-
ing up to 750 volts.
5.3.4.3 Recorder. Compatible with the
output voltage range of the electrometer.
'Mention of .trade n3mes or specific prod-
ucts does not constitute an endorsement by
the Environmental Protection Agency.
FEDERAL REGISTER, VOL 43, NO. SI-WEDNESDAY, MARCH IS, I97»
43
-------
RULES AND REGULATIONS
5 -i Gas Chromatograph Columns The
CO:L_TJI sysitrn rr.u^ be dernor.s:rau-d ta be
ca^atlc cf resolve;:' three major reduced
SLLiur compounds: H,S. COS. ar,J CS,.
To Cemoasi-i'.e :J~,ai adequate resolution
hia seen acr.:oed ihe tester rr.-ist submit a
ch.-vrr.acojrr-r'" of a calibration pas coniain-
uit; a_. ilj-n rtcuced sulfur corr.pcur.d5; in
ii'.f cor.Trural ion range cf the applicable
i*. ar.co.ra. Ac'.'QLJiu- resolution w;il be de-
Jiiitd aj t^at line separation of adjacent
pc:.^' wr.tri i3u amplifier attenuation is set
so mat trie srr..i;k-r peak is at least 50 per-
cer.i of full sraie. Base llr.e separation is de-
iinod as a reium to zero =5 percent in the
interval between ptaKs. Systems not meet-
inc tr;i prepurified grade
or better.
6.2 Combustion Gas. Oxygen (d) or air.
research purity or better.
6,3 Carrier Gas. Prepurified grade or
better.
6.4 Diluent, Air containing less than 0.5
ppm total sulfur compounds and less than
10 ppm each of moisture and total hydro-
carbons.
6.5 Calibration Gases. Permeation tubes,
one each of H:S. COS, and CS,. gravimetri-
cally calibrated and certified at some conve-
nient operating temperature. These tubes
consist of hermetically sealed FEP Teflon
tubing in which a liquified gaseous sub-
stance is enclosed. The enclosed gas perme-
ates through the tubing ws.ll at a constant
rate. When the temperature is constant.
calibration pases covering a wide range of
known concentrations can be generated by
varying and accurately measuring the flow
rate of diluent gas passing over the tubes.
These calibration gases are used to calibrate
the GC/FPD system and the dilution
system.
7. Pretest Procedures
The following procedures are optional but
would be helpful tn preventing any problem
which might occur later and invalidate the
entire test.
7.1 After the complete measurement
system has been set up at the site and
deemed to be operational, the following pro-
cedures should be completed before sam-
pling is mitiatedL
7.1.1 Leak Test. Appropriate leak test pro-
cedures should be employed to verify the in-
tegrity of all components, sample lines, and
connections. The following leak test proce-
dure is supcesifd: For components upstream
of the sample pump, attach the probe end
of the sampie line 10 a manometer or
vacuum gauge, start the pump and pull
greater man 50 mm i2 in.) Hp vacuum, close
off the pump omK-i. and then stop the
purr.o and ascertain ihat there is no leak for
1 mir.uic. Fot components after the purnp.
appiy a slight pus:t:ve pressure and check
for leaks py a. pu ;>•;-{: a liquid 'deterrent in
water, for example) at each joint. Bubbling
indicates the presence of a leak.
7.1-2 System Performance. Since the com-
plete system is cz.libra'ed following each
test, the precise calibration of each compo-
nent is not critical. However, these compo-
nents should be verified to be operating
properly. This verification can be performed
by observing the response of flowmeters or
of the GC output to changes in flow rates or
calibration ?as concentrations and ascer-
taining the response to be within predicted
limits. If any component or the complete
system fails to respond in a normal and pre-
dictable manner, the source of the discrep-
ancy should be identifed and corrected
before proceeding.
8. Calibration
Prior to any sampling run. calibrate the
system using the following procedures. (If
more than one run is performed during any
24-hour period, a calibration need not be
performed prior to the second and any sub-
sequent runs. The calibration must, howev-
er, be verified as prescribed, in section 10.
after the last run made within the 24-hour
period.)
8.1 General Considerations. This section
outlines steps to be followed for use of the
GC/FPD and the dilution system. The pro-
cedure does not include detailed instruc-
tions because the operation of these systems
is complex, and it requires an understanding
of the individual system being used. Each
system should include a written operating
manual describing in detail the operating
procedures associated with each component
in the measurement system. In addition, the
operator shuld be familiar with the operat-
ing principles of the components; particular-
ly the GC/PPD. The citations in the Bib-
liography at the end of this method are rec-
ommended for review for this purpose.
8.2 Calibration Procedure. Insert the per-
meation tubes into the tube chamber. Check
the bath temperature to assure agreement
with the calibration temperature of the
tubes within sQ.rc, Allow 24 hours for the
tubes to equilibrate. Alternatively equilibra-
tion may be verified by injecting samples of
calibration gas at 1-hour intervals. The per-
meation tubes can be assumed to have
reached equilibrium when consecutive
hourly samples agree within the precision
limits of section 4.1.
Vary the amount of air flowing over the
tubes to produce the desired concentrations
for calibrating the analytical and dilution
systems. The air flow across the tubes must
at all times exceed the flow requirement of
the analytical systems. The concentration in
parts per million generated by a bube con-
taining a specific permeant can be calculat-
ed as follows:
Equation 15-1
where:
C= Concentration of permeant produced
in ppm.
Pr=Permeation rate of '.he tube in pg/
nun.
M*Mo)ecular weight of the permeari: g '
g-moie.
L=Flow rate. 1/min. of air over perm earl
-------
10S72
the scacle probe is clo?£*d t-ith paniculate
matter. If the probe fc found to be ciogueS.
the test must be stopped and the results up
to that point discarded Testing may resume
after cleaning Uic probr or replacing it with
a clean one. Alter each run. the sample
probe must be inspected and, if necessary
dismantled and cleaned.
20. Peat-Tat Procedures
10.1 Sample Line Loss. A known concen-
tration of hydrogen sulfide at the level of
the applicable standard. ±20 percent, must
be introduced into the sampling system at
the opening of the probe in sufficient Quan-
tities to ensure that there is an excess of
sample which must be vented to the atmo-
sphere. The sample must be transported
through the entire sampling system to the
measurement system to the normal manner.
The resulting measured concentration
should be compared to the known value to
determine the sampling system loss. A sam-
pling system loss of more than 20 percent Is
unacceptable. Sampling losses of 0-20 per-
cent must be corrected by dividing the re-
sulting sample concentration by the frac-
tion of recovery. The known gas sample may
be generated using permeation tubes. Alter-
natively, cylinders of hydrogen sulfide
mixed in air may be used provided they are
traceable to permeation tubes. The optional
pretest procedures provide a good guideline
for determining if then are leaks in the
sampling system.
10.2 Reealibration. After each run. or
after a series of runs made within a 24-hour
period, perform a partial recalibration using
the procedures in section 6. Only H»S (or
other permeant) need be used to recalibrate
the CC/FFD analysis system (8.3> and the
dilution system (8.5).
10.3 Determination of Calibration Drift.
Compare the calibration curves obtained
prior to the runs, to the calibration curves
obtained under paragraph 10.1. The calibra-
tion drift should not exceed the limits set
forth in paragraph 4^- If the drift exceeds
this limit, the intervening run or runs
should be considered cot valid. The tester,
however, may instead have the option of
choosing the calibration data set which
would give the highest sample values.
11. Calculations
11.1 Determine the concentrations of each
reduced sulfur compound detected directly
from the calibration curves. Alternatively,
the concentrations may be calculated using
the equation for the least squares line.
1L2 Calculation of SO, Equivalent SO,
equivalent will be determined for each anal-
ysis made by summing the concentrations of
each reduced sulfur compound resolved
during the given analysis.
SO, equivalent=KH,S. COS, 2 CS.M
Equation 15-2
where:
SO. equivalent-The sum of the concen-
tration of each of the measured com-
pounds (COS. HJ3, C&) expressed as
sulfur dioxide in ppm.
HfS* Hydrogen sulfide. ppm.
COS=Carbonyl sutlide. ppm.
CS,-Carbon disulfide. ppm.
d=Dilution factor, dimensionless.
11.3 Average SO. equivalent will be deter-
mined as follows:
RULES AND REGULATIONS
Average SOj equivalent
Eouaticn 15-3
where:
Average SOt equivalent,-Average SO,
equivalent in ppm, dry basis.
Average SOi equi\-alent,»SO. in ppm as
determined by Equation 15-2.
NssNumber of analyses performed.
BwoaFraction of volume of water vapor
in the gas stream as determined by
Method 4—Determination of Moisture
in Stack Cases (36 FR 24887).
12. Example System
Described below is a system utilized by
EPA in gathering NSPS data. This system
does not now reflect, all the latest develop-
ments in equipment and column technology.
but it does represent one system that has
been demonstrated to work,
12.1 Apparatus.
12.1.1 Sample System.
12.1.1.1 Probe. Stainless steel tubing. 6.35
mm .
12,1.4.1 Tube Chamber. Class chamber of
sufficient dimensions to house permeation
tubes.
12.1.4.2 Mass Flowmeters. Two mass flow-
meters in the range 0-3 1/min. and 0-10 I/
min. to measure air flow over permeation
tubes at ±2 percent. These flowmeters shall
be cross-calibrated at the beginning of each
test. Using a convenient flow rate in the
measuring range of both flowmeters. set
and monitor the flow rate of gas over the
permeation tubes. Injection of calibration
gas generated at this flow rate as measured
by one flowmeter followed by injection of
calibration gas at Che same flow rate as mea-
sured by the other flowmeter should agree
within the specified precision limits. If they
do not. then there Is & problem with the
mass flow measurement. Each mass flow-
meter shall be calibrated prior to the first
test with a wet test meter and th greater at
least once each year.
12.1.4^ Constant Temperature Bath. Ca-
pable of maintaining permeation tubes at
certification temperature of 30' C within
.±o.rc.
12.2 Reagents.
122,1 Fuel. Hydrogen (H.) prepuruUed
grade or better.
12.2.8 Combustion Gas. Oxygen (O.) re-
search purity or better.
12^3 Carrier Gas. Nitrogen (N,) prepuri-
fied grade or better.
12^.4 Diluent. Air containing less than 0.5
ppm total sulfur compounds and less than
10 ppm each of moisture and total hydro-
carbons, and filtered using MSA filters
46727 and 79030. or equivalent. Removal of
sulfur compounds can be verified by inject-
ing dilution air only, described in section
compressed Air. 60 psig for CC
valve actuation.
12.2.S Calibration Gases. Permeation
tubes gratfmetrically calibrated and certi-
fied at 30.0* C.
12.3 Operating Parameters. The operating
parameters for the GC/FPD system are as
follows: nitrogen carrier gas flow rate of 100
cc/min. exhaust temperature of 110' C. de-
tector temperature 105" C. oven tempera-
ture of 40' C. hydrogen flow rate of SO cc/
minute, oxygen flow rate of 20 cc/minute.
and sample flow rate of SO cc/minute.
12.4 Analysis. The sample valve is actu-
ated for I minute in which time an aliquot
of diluted sample Is injected onto the sepa-
ration column. The valve is then deactivated
for the remainder of analysis cycle in which
time the sample loop is refilled and the sep-
aration column continues to be f oreflushed.
The elution time for each compound will be
determined during calibration.
FEDERAL «GKTOt, VOL. 43, NO. Sl-WEDNBDAY, MARCH IS, IW*
45
-------
RULES AND REGULATIONS
10373
13. Bibliography
13-1 O'Keefie. A. E. and G. C. Orirnan.
"Primary Standards for Trace Gas Analy-
se " A.-.-I. Chem. 35.76:) (JfrS6>.
13.1'Stexcns. R. K.. A. E. O'Keeffe. and
G. C. Ortman. "Absolute Caiibraiien ni a
Flame Phoiomc'trr Deiec:or 10 Vohi.ii.r
Suirur Corr.pouncis i.1 Sub-Pirl-Per-M'.llicn
Le\c!s." Kfi'.'!ro:i.m., R. K. Stevens, and R.
Baum^ircner. "An Anaiyuoai Syiiem De-
Si^ned to Measure MulupJe Malodorous
Compounds Related to Kraft MiU Activi-
ties." Presented a: ihe 12:h Conr^rcrifc1 on
Meihods m Air Pollution and Ir.c'jsinul Hy-
giene Studies, University of Sojlhern Ca!i-
lorn:a, L-os Anpeles, Calif. April 6-8,1971.
13.4 Devonald. R. H., R. S. Serenius. ai.d
A. D. Mclntyre. "Evaluation of the Flame
Photometric Detector for Analysis of Suiiur
Compound.1-." P\:lp and Paper Magazine of
CnraJa. 73.3 (March. ]9V2).
13.5 Grtmley. K. W., \v. S. Smsiti, and
R. M. Martin. "The Use of £ Dvi.an-.ic Dilu-
tion System in the Cor,ci:;onir.£ o: Stsck
G^ses for Automated Anal VMS by F. Mobile
Sampling Van" Prescnicti at the 6>rd
Annual APCA Meeting in St. Louis, :.io.
June 14-19.1970.
13.6 General Reference. Standard Meth-
ods of Chemical Analysis Volume III A and
B In,?:rumcnt£l Xc.-ihocis. Sixth Edition,
Van Nostrand Remnold Co.
EFR Doc. 7S-6G33 Filed 3-14-78; 8:45 am3
FEDERAL REGISTER, VOL. 43, NO. 51— WEDNESDAY, MARCH IS, 197fl
-------
oxygen
made in the
§ 60.284Xc)<3>.
to 8 volume percent
rrections shall be
ified in
APPENDIX A—REFERENCE METHODS
(3) Method 16 and Method 17 are
added to Appendix A as follows:
METHOD t«. SEMICOKTINXTOUS DETERMINATION
OF SULFUR EMISSIONS FROM STATIONARY
SOURCES
Introduction
The method described below uses the
principle of gas chromatographic separation
and name photometric detection. Since
there are many systems or sets of operating
conditions that represent usable methods of
determining sulfur emissions, all systems
which employ this principle, but differ only
in details of equipment and operation, may
be used as alternative methods, provided
that the criteria set below are met.
1. Principle and Applicability.
1.1 Principle. A gas sample Is extracted
from the emission source and diluted with
clean dry air. An aliquot of the diluted
sample is then analyzed for hydrogen sul-
Hde (HaS). methyl mercaptan (MeSH). di-
methyl sulfide (DMS) and dimethyl disul.
fide (DMDS) by gas chromatographic (GO
separation and flame photometric detection
(FPD). These four compounds are known
collectively as total reduced sulfur (TBS).
1.2 Applicability. This method Js applica-
ble for determination of TRS compounds
from recovery furnaces, lime kilns, and
smelt dissolving tanks at kraf t pulp mills.
2. Range and Sensitivity.
2.1 Range. Coupled with a gas chromato-
graphic system utilizing a ten milliliter
sample size, the maximum limit of the FPD
for each sulfur compound is approximately
1 ppm. This limit is expanded by dilution of
the sample gas before analysis. Kraft mill
gas samples are normally diluted tenfold
(9:1). resulting in an upper limit of about 10
ppm for each compound.
For sources with emission levels between
10 and 100 ppm, the measuring range can be
best extended by reducing the sample size
to 1 maiUfter.
* 2.2 Using the sample size, the minimum
detectable concentration is approximately
SO ppb.
3. Interferences.
3.1 Moisture Condensation. Moisture
condensation in the sample delivery system,
the analytical column, or the FPD burner
block can cause losses or interferences. This
potential is eliminated by heating the
sample line, and by conditioning the sample
with dry dilution air to lower its dew point
below the operating temperature of the
GC/FPD analytical system prior to analysis.
3.2 Carbon Monoxide and Carbon Diox-
ide. CO and CO, have substantial desensitiz-
ing effect on the flame photometric detec-
tor even after 9:1 dilution. Acceptable sys-
tems must demonstrate that they have
eliminated this interference by someproce-
dure such as eluting these compounds
before any of the compounds to be mea-
sured. Compliance with this requirement
can be demonstrated by submitting chroma-
tograms of calibration gases with and with-
out CO. in the diluent gas. The CO. level
should be approximately 10 percent for the
case with CO, present. The two chromato-
RULES AND* REGULATIONS
graphs should show agreement within the
precision limits of Section 4.1.
3.3 Particulate Matter. Participate
matter in gas samples can cause interfer-
ence by eventual clogging of the analytical
system. This interference must be eliminat-
ed by use of a probe filter.
3.4 Sulfur Dioxide. SO, is not a specific
Interferent but may be present in such large
amounts that it cannot be effectively sepa-
rated from other compounds of interest.
The procedure must be designed to elimi-
nate this problem either by the choice of
separation columns or by removal of SO,
from the sample.
Compliance with this section can be dem-
onstrated by submitting chromatographs of
calibration gases with SOt present in the
same quantities expected from the emission
source to be tested. Acceptable systems
shall show baseline separation with the am-
plifier attenuation set so that the reduced
sulfur compound of concern is at least 50
percent of full scale. Base line separation is
defined as a return to zero ± percent in the
interval between peaks.
4. Precision and Accuracy.
4.1 GC/FPD and Dilution System Cali-
bration Precision. A series of three consecu-
tive injections of the same calibration gas,
at any dilution, shall produce results which
do not vary by more than ±3 percent from
the mean of the three injections.
4.2 GC/FPD and Dilution System Cali-
bration Drift. The calibration drift deter-
mined from the mean of three Injections
made at the beginning and end of any 8-
hour period shall not exceed ± percent.
4.3 System Calibration Accuracy. The
complete system must quantitatively trans-
port and analyze with an accuracy of 20 per-
cent. A correction factor is developed to
adjust calibration accuracy to 100 percent.
5. Apparatus (See Figure 16-1).
5.1.1 Probe. The probe must be made of
inert material such as stainless steel or
glass. It should be designed to incorporate a
filter and to allow calibration gas to enter
the probe at or near the sample entry point.
Any portion of the probe not exposed to the
stack gas must be heated to prevent mois-
ture condensation.
5.1.2 Sample Line. The sample line must
be made of Teflon,1 no greater than 1.3 cm
prepurified
grade or better.
6.2 Combustion Gas. Oxygen (O.) or air.
research purity or better.
6.3 Carrier Gas, Prepurified grade or
better.
6.4 Diluent. Air containing less than 50
ppb total sulfur compounds and less than 10
ppm each of moisture and total hydrocar-
bons. This gas must be heated prior to
mixing with the sample to avoid water con-
densation at the point of contact.
6.5 Calibration Gases. Permeation tubes,
one each of H»S. MeSH, DMS. and DMDS,
agravimetrically calibrated and certified at
some convenient operating temperature.
These tubes consist of hermetically sealed
FEP Teflon tubing In which a liquified gas-
eous,substonce is enclosed. The enclosed gas
permeates through the tubing wall at a con-
stant rate. When the temperature is con-
stant, calibration gases Governing a wide
range of known concentrations can be gen-
erated by varying and accurately measuring
the flow rate of diluent gas passing over the
tubes. These calibration gases are used to
calibrate the GC/FPD system and the dilu-
tion system.
7. Pretest Procedure*. The^f ollowlng proce-
dures are options! but would be helpful In
preventing any problem which might occur
later and invalidate the entire test.
FEDERAL MGlSTtt, VOL 43, NO. 37-THUKDAY, FEBRUARY 23, 197»
47
-------
RULES'AND REGULATIONS
7.1 After the complete measurement
system has been set up at the site and
deemed to be operational, the following pro-
cetiures should be completed before iani-
phn« is in:' iMi-d.
7.1.1 L<>Ak Test. Appropriate leak test
procedure should be employed to verify the
integrity of all components, sample lines.
and coniH'dions. The following leak test
procedure is suKK^ted: For components up-
stream of the sample pump, attach the
probe end of the sample line to a ma- no-
meter or vacuum gaut:o, start the pump and
pull greater than 50 nm (2 In.) Hg vacuum.
clcse off the pump cutlet, and then stop the
pump and ascertain lhat there is no leak for
1 minute. For components after the pump.
apply a slight positive pressure and check
for leaks by applying a liquid (detergent in
^ater, for example) at each joint. Bubbling
indicates the presence of a leak.
7.1.2 System Performance. Since the
complete system is calibrated following each
test, the precise calibration of each compo-
nent is not critical. However, these compo-
nents should be verified to be operating
properly. This X'erification can be performed
by observing the response of flowmeters or
of the GC output to changes in flow rates or
calibration gas concentrations and ascer-
taining the response to be within predicted
limits. In any component, or if the complete
system fails to respond in a normal and pre-
dictable manner, the source of the discrep-
ancy should be identified and corrected
before proceeding.
8. Calibration. Prior to any sampling run.
calibrate the system using the following
procedures. (If more than one run is per-
formed during any 24-hour period, a calibra-
tion need not be performed prior to the
second and any subsequent runs. The cali-
bration must, however, be verified as pre-
scribed in Section 10, after the last run
made within the 24-hour period.)
8.1 General Considerations. This section
outlines steps to be followed for use of the
GC/FPD and the dilution system. The pro-
cedure does not include detailed instruc-
tions because the operation of these systems
is complex, and it requires a understanding
of the Individual system being used. Each
system should include a written operating
manual describing in detail the operating
procedures associated with each component
in the measurement system. In addition, the
operator should be familiar with the operat-
ing principles of the components; particular-
ly the GC/FPD. The citations in the Bib-
liography at the end of this method are rec-
ommended for review for this purpose.
8.2 Calibration Procedure. Insert the per-
meation tubes into the tube chamber.
Check the bath temperature to assure
agreement with the calibration temperature
of the tubes within ±0.1' C. Allow 24 hours
for the tubes to equilibrate. Alternatively
equilibration may be verified by injecting
samples of calibration gas at 1-hour Inter-
vals. The permeation tubes can be assumed
to have reached equilibrium when consecu-
tive hourly samples agree within the preci-
sion limits of Section 4.1.
Vary the amount of air flowing over the
tubes to produce the desired concentrations
for calibrating the analytical and dilution
systems. The air flow across the tubes must
at all times exceed the flow requirement of
the analytical systems. The concentration in
parts per million generated by a tube con-
taining a specific permeant can be calculat-
ed as follows: p
C Kfjf
Equation 16-1
where:
C=Concentration of permeant produced in
ppm.
Pt=Permeation rate of the tube in MP/'min.
M = Molecular weight of the permeant
-------
11.3 Average TRS. The average TRS will
be determined as follows:
N
r TR$
Average TRS.
Average TRS=Average total reduced suflur
in ppm, dry basis.
TRS, •= Total reduced sulfur in ppra as deter-
mined by Equation 16-2.
N=Number of samples.
B«= Fraction of volume of water vapor in
the gas stream as determined by method
4—Determination of Moisture in Stack
Gases (36 FR 24887).
11.4 Average concentration of individual
reduced sulfur compounds. >
C -
Equation 16-3
where:
S,=Concentration of any reduced sulfur
compound from the i:h sanipie Injec-
tion, ppm.
C=Average concentration of any one of the
reduced sulfur compounds for the entire
run, ppm.
N=Number of injections m any run period.
12. Example System. Described below Is a
system utilised by EPA in gathering NSPS
data. This system does not now reflect all
the latest developments in equipment and
column technology, but it does represent
one system that has been demonstrated to
work.
12.1 Apparatus.
12.1.1 Sampling System.
12.1.1.1 Probe. Figure 16-1 Illustrates the
probe used in lime kilns and ether sources
where significant amounts of paniculate
matter are present, the probe is designed
with the deflector shield placed between the
sample and the gas inlet holes and the glass
wool plugs to reduce clogging of the filter
and possible adsorption of sample gas. The
exposed portion of the probe between the
sampling port and the sample line Is heated
with heating tape.
12.1.1.2 Sample Line %• inch inside diam-
eter Teflon tubing, heated to 120' C. This
temperature is controlled by a thermostatie
heater.
12.1.1.3 Sample Pump. Leakless Teflon
coated diaphragm type or equivalent. The
pump head is heated to 120* C by enclosing
It in the sample dilution box (12.2.4 below).
12.1.2 Dilution System. A schematic dia-
gram of the dynamic dilution system is
Given in Figure 16-2. The dilution system is
constructed such that all sample contacts
are made of inert materials. The dilution
system which is heated to 120* C must be ca-
pable of a minimum of 9:1 dilution of
sample. Equipment used in the dilution
system is listed below:
12.1.2.1 Dilution Pump. Model A-150
Kohmyhr Teflon positive displacement
type, nonadjustable 150 cc/min. ±2.0 per-
cent, or equivalent, per dilution stage. A 9:1
dilution of sample Is accomplished by com-
RULES AND REGULATIONS
binlng 150 cc of simple with 1.350 cc of
clean dry air as shown in Figure 16-2.
12.1.2.2 Valves. Three-way Teflon sole-
noid or manual type.
12.1.2.3 Tubing. Teflon tubing and fit-
tings are used throughout from the sample
probe to the GC/FPD to present an inert
surface for sample gas..
12.1.2.4 Box. Insulated box. heated and
maintained at 120' C, of sufficient dimen-
sions to house dilution apparatus.
12.1.2.5 Flowmcters. Rotameters or
equivalent to measure now from 0 to 1500
ral/min ±1 percent per dilution stage.
12.1.3 Gaa Chromatograph Columns.
Two types of columns are used for separa-
tion of low and high molecular weight
sulfur compounds;
12.1.3.1 Low Molecular Weight Sulfur
Compounds Column (GC/FFD-1).
12.1.3.1 Separation Column. 11 m by 2.16
mm (36 ft by 0.085 in) Inside diameter
Teflon tubing packed with 30/60 mesh
Teflon coated with 5 percent polyphenyl
ether and 0.05 percent orthophosphorlc
acid, or equivalent (see Figure 16-3).
12.1.3.1.2 Stripper or Precclumn. 0.6 ra
by 2.16 mm (2 ft by 0.085 in) inside diameter
Teflon tubing packed as in 5.3.1.
12.1.3.1.3 Sample Valve. Teflon 10-port
gas sampling valve, equipped with a 10 ml
sample loop, actuated by compressed air
(Figure 16-3).
12.1.3.1.4 Oven. For containing sample
valve, stripper column and separation
column. The oven should be capable of
maintaining an elevated temperature rang-
ing from ambient to 100* C, constant within
±rc.
12.1.3.1.5 Temperature Monitor. Thermo-
couple pyrometer to measure column oven,
detector, and exhaust temperature ±1* C.
12.1.3.1.6 Flow System. Gas metering
system to measure sample flow, hydrogen
flow, and oxygen flow (and nitrogen carrier
gas flow).
12.1.3.1.7 Detector. Flame photometric
detector.
12.1.3.1.8 Electrometer. Capable of full
scale amplification of linear ranges of 10**
to 10'* amperes full scale.
12.1.3.1.9 Power Supply. Capable of deli-
vering up to 750 volts.
12.1.3.1.10 Recorder. Compatible with
the output voltage range of the electrom-
eter.
12.1.3.2 High Molecular Weight Com-
pounds Column (GC/FFD-11).
12.1.3.2.1. Separation Column. 3.05 m by
2.16 mm (10 ft by 0.0885 in) inside diameter
Teflon tubing packed with 30/60 mesh
Teflon coated with 10 percent Triton X-305.
or equivalent.
12.1.3.2.2 Sample Valve. Teflon 6-port gas
sampling valve equipped with a 10 ml
sample loop, actuated by compressed air
(Figure 16-3).
12.1.3.2.3 Other Components. All compo-
nents same as in 12.1.3.1.4 to 12.1.3.1.10.
12.1.4 Calibration. Permeation tube
system (figure 16-4).
12.1.4.1 Tube Chamber. Glass chamber
of sufficient dimensions to house perme-
ation tubes.
12.1.4.2 Mass Flowmeters. Two mass
flowmeters in the range 0-3 1/min. and 0-10
1/min. to measure air flow over permeation
tubes at ±2 percent. These flowmeters shall
be cross-calibrated at the beginning of each
test. Using a convenient flow rate in the
measuring range of both flowmeters. set
and monitor the flow rate of gas over the
permeation tubes. Injection of calibration
7577
gas generated at this flow rate as measured
by one flowmeter followed by injection of
calibration gas at the same flow rate as m=a-
sured by the other flowmeter should asrree
within the specified precision limits. If they
do not, then there is a problem with the
mass flow measurement. Each mass flow-
meter shall be calibrated prior to the first
test with a wet test meter and thereafter, at
least once each year.
12,1.4.3 Constant Temperature Bath. Ca-
pable of maintaining permeation tubes at
certification temperature of 30' C. within
±0.1- C.
12.2 Reagents
12.2.1 Fuel. Hydrogen (H.) prepurlfled
grade or better.
12.2.2. Combustion Gas. Oxygen (O,) re-
search purity or better.
12.2.3 Carrier Gas. Nitrogen (N,) prepuri-
f ied grade or better.
12.2.4 Diluent. Air containing less than
50 ppb total sulfur compounds and less than
10 ppm each of moisture and total hydro-
carbons, and filtered using MSA filters
46727 and 79030, or equivalent. Removal of
sulfur compounds can be verified by inject-
ing dilution air only, described in Section
8.3.
12.2.5 Compressed Air. 60 psig for GC
valve actuation.
12.2.6 Calibrated Gases. Permeation
tubes gravimetrteally calibrated and certi-
fied at 30.0- C.
12.3 Operating Parameters.
12.3.1 Low-Molecular Weight Sulfur
Compounds. The operating parameters for
the GC/FPD system used for low molecular
weight compounds are as follows: nitrogen
carrier gas flow rate of 50 cc/min. exhaust
temperature of 110* C, detector temperature
of 105' C, oven temperature of 40' C, hydro-
gen flow rate of 60 cc/min. oxygen How rate
of 20 cc/min. and sample flow rate between
20 and 80 cc/min.
12.3.2 High-Molecular Weight Sulfur
Compounds. The operating parameters for
the GC/FPD system for high molecular
weight compounds are the same as in 12.3.1
except: oven temperature of 70* C, and ni-
trogen carrier gas flow of 100 cc/min.
12.4 Analysis Procedure.
12.4.1 Analysis. Aliquots of diluted
sample are injected simultaneously into
both GC/FPD analyzers for analysis. GC/
FPD-I is used to measure the low-molecular
weight reduced sulfur compounds. The low
molecular weight compounds Include hydro-
gen sulfide, methyl mercaptan, and di-
methyl sulfide. GC/FPD-II is used to re-
solve the high-molecular weight compound.
The high-molecular weight compound is di-
methyl disuUUie.
12.4.1.1 Analysis of Low-Molecular
Weight Sulfur Compounds. The sample
valve is actuated for 3 minutes in which
time an aliquot of diluted sample is injected
into the stripper column and analytical
column. The valve is then deactivated for
approximately 12 minutes in which time,
the analytical column continues to be fore-
flushed, the stripper column is backflushed,
and the sample loop is refilled. Monitor the
responses. The elution time for each com-
pound will be determined during calibra-
tion.
12.4.1.2 Analysis of High-Molecular
Weight Sulfur Compounds. The procedure
Is essentially the same as above except that
no stripper column is needed.
13. BidliOffrapfty. —,,
13.1 O'Keeffe. A. E. and G. C. Ortman.
"Primary Standards for Trace Gas Analy-
FEDERAL REGISTER, VOL 43. NO. 37—THURSDAY, FEUUART 23, 1971
49
-------
7578 RULES ANO REGULATIONS
sis." Analytical Chemical Journal. 38,160 Compounds Rotated to Kraft Mill Activi- 13.5 Grimlry. K. W., W. S. Smith, and R
f 1966). ties." Presented at the 12th Conference on M. Mar'.in. "The Urc of a Dynamic Dilution
13.2 S'.evens. R. K.. A. E. O'Keeffe. and Methods in .Air Pollution and Industrial Hy- System in the CnrtMniiinr of Sin.ck Ga,,,-.;
G. C. Orlman. "Absolute Calibration of a giene Studies. Univeisity of Southern Call- for A'.itonw'id AM) VMS by a Mobile S«.m-
Hame Photometric Detector to Volatile fornia, Los AneHes. CA. April 6-8, 1971. pimp Van." Presir.'-d at the 63rd Annual
Sulfur Compounds at Sub-Part-Per-Million rvvonuld R H R S Sercnius and APCA Mi-tunx in St. Louis. Mo. June 14.15.
Levels." Environmental Science and Tech- 13A Oe\ona\d. R. H.. R. S. Sercnius. and
no!o.;y. 3.7 'July. 1969). A- D- Mclntyre. "Evaluation of the Flame 13 6 Oenerel R(,fcri..nce. Standard Mrih-
13.3 Muliclc. J. D.. R. K. Stevens, and R. Photometric Detector for Analysis of Sulfur ods o! chemical Arilysis Volume III A a.-.d
Baumgardner. "An Analytical System De- Compounds." Pulp and Paper Magazine of 3 Instrumental Methods. Sixth Edition.
signed to Measure Multiple Malodorous Canada. 73,3 (March. 1972). Van Nostrand Reinhold Co.
FEDERAL REGISTER, VOL 43, NO. 37—THURSDAY, FEBRUARY 23, 1*71
50
-------
tickets shall have no redemption
value.
(PR Doc. 79-1210 Filed 1-11-79: 8:45 am)
[6560-01-M]
Title 40—Protection of Environment
CHAPTER I—ENVIRONMENTAL
PROTECTION AGENCY
[PRL 1012-21
PART 60—STANDARDS OF PERFORM.
ANCE FOR NEW STATIONARY
SOURCES
Appendix A—Reference Method 16
AGENCY: Environmental Protection
Agency.
ACTION: Amendment.
SUMMARY: This action amends Ref-
erence Method 16 for determining
total reduced sulfur emissions from
stationary sources. The amendment
corrects several typographical errors
and improves the reference method by
requiring the use of a scrubber to pre-
vent potential interference from high
SO, concentrations. These changes
assure more accurate measurement of
total reduced sulfur (TRS) emissions
but do not substantially change the
reference method.
SUPPLEMENTARY INFORMATION:
On Pebrurary 23. 1978 (43 FR 7575),
Appendix A—Reference Method 16 ap-
peared with several typographical
errors or omissions. Subsequent com-
ments noted these and also suggested
that the problem of high SO, concen-
trations could be corrected by using a
scrubber to remove these high concen-
trations. This amendment corrects the
errors of the original publication and
slightly modifies Reference Method 16
by requiring the use of a scrubber to
prevent potential interference from
high SOj concentrations.
Reference Method 16 is the refer-
ence method specified for use in deter-
mining compliance with the promul-
gated standards of performance for
kraft pulp mills. The data base used to
develop the standards for kraft pulp
mills has been examined and this addi-
tional requirement to use a scrubber
to prevent potential interference from
high SO, concentrations does not re-
Quire any change to these standards of
performance. The data used to develop
these standards was not gathered from
kraft pulp mills with high SO, concen-
trations: thus, the problem of SO, in-
terference was not present in the data
base. The use of a scrubber to prevent
this potential interference in the
future, therefore, is completely con-
sistent with this data base and the
promulgated standards.
12, l»79
The increase in the cost of determin-
ing compliance with the standards of
performance for kraft pulp mills as a
result of this additional requirement
to use a scrubber in Reference Method
16. is negligible. At most, this addition-
al requirement could increase the cost
of a performance test by about 50 dol-
lars.
Because these corrections and addi-
tions to Reference Method 16 are
minor in nature, impose no additional
substantive requirements, or do not re-
quire a change in the promulgated
standards of performance for kraft
pulp mills, these amendments are pro-
mulgated directly.
EFFECTIVE DATE: January 12, 1979.
FOR FURTHER INFORMATION
CONTACT:
Don R. Goodwin, Director, Emission
Standards and Engineering Division,
(MD-13) Environmental Protection
Agency. Research Triangle Park.
North Carolina 27711. telephone
number 919-541-5271.
Dated: January 2. 1979.
DODOLAS M. COSTIE.
Administrator.
Part 60 of Chapter I, Title 40 of the
Code of Federal Regulations is amend-
ed as follows:
APPENDIX A—REFEBSHCE METHODS
In Method 16 of Appendix A. Sec-
tions 3.4, 4.1, 4.3. 5. 5.5.2, 6, 8.3, 9.2,
10.3. 11.3. 12.1, 12.1.1.3. 12.1.3.1.
12.1.3.1.2. 12.1.3.2. 12.1.3.2.3, and 12.2
are amended as follows:
1. In subsection 3.4. at the end of the
first paragraph, add: "In the example
system, SO, is removed by a citrate
buffer solution prior to GC injection.
This scrubber will be used when SO«
levels are high enough to prevent
baseline separation from the reduced
sulfur compounds."
2. In subsection 4.1, change "± 3 per-
cent" to "± 5 percent."
3. In subsection 4.3, delete both sen-
tences and replace with the following:
"Losses through the sample transport
system must be measured and a cor-
rection factor developed to adjust the
calibration accuracy to 100 percent."
4. After Section 5 and before subsec-
tion 5.1.1 insert "5.1. Sampling."
5. In Section 5, add the following
subsection: "5.3 SO, Scrubber. The
SO, scrubber is a midget impinger
packed with glass wool to eliminate
entrained mist and charged with po-
tassium citrate-citric acid buffer."
Then increase all numbers from 5.3 up
to and including 5.5.4 by 0.1, e.g..
change 5.3 to 5.4. etc.
6. In subsection 5.5.2. the word
"lowest" in the fourth sentence is re-
placed with "lower." «
RULES ANO RSGUIATIONS
7. In Section 6. add the following
subsection: "6.6 Citrate Buffer. Dis-
solve 300 grams of potassium citrate
and 41 grams of anhydrous citric acid
in 1 liter of deionized water. 284 grams
of sodium citrate may be substituted
for the potassium citrate."
8. In subsection 8.3, in the second
sentence, alter "Bypassing the dilu-
tion system." insert "but using the SO>
scrubber," before finishing the sen-
tence.
9. In subsection 9.2. replace sentence
with the following: "Aliquots of dilut-
ed sample pass through the SO, scrub-
ber, and then are injected in'o the
GC/FPD analyzer for analysis,"
10. In subsection 10.3. "paragraph"
in the second sentence is corrected
with "subsection."
II. In subsection 11.3 under B,, defi-
nition, insert "Reference" before
"Method 4."
12. In subsection 12.1.1.3 "U2.2.4
below)" is corrected to "(12.1.2.4
below)."
13. In subsection 12.1. add the fol-
lowing subsection: "12.1.3 SO, Scrub-
ber. Midget impinger with 15 ml of po-
tassium citrate buffer to absorb SO, in
the sample." Then renumber existing
section 12.1.3 and following subsec-
tions through and including 12.1.4.3 as
12.1.4 through 12.1.5.3.
14. The second subsection listed as
"12.1.3.1" (before corrected in above
amendment) should be "12.1.4.1.1."
15. In subsection 12.1.3.1 (amended
above to 12.1.4.1) correct "GC/FPD-1
to "GC/FPD-I."
16. In subsection 12.1.3.1.2 (amended
above to 12.1.4.1.2) omit "Packed as in
5.3.1." and put A period after "tubing."
17. In subsection 12.1.3.2 (amended
above to 12.1.4.2) .correct "GC/FPD-
11" to "GC/FPD-I1."
18. In subsection 12.1.3.2.3 (amended
above to 12.1.4.2.3) the phrase
"12.1.3.1.4. to 12.1.3.1.10" is corrected.
to read "12.1.4.1.5 to 12.1.4.1.10."
19. In subsection 12.2. add the fol-
lowing subsection: "12.2.7 Citrate-
Buffer. Dissolve 300 grams of potas-
sium citrate and 41 grams of anhy-
drous*citric acid in 1 HUT of deioni^^d
water. 284 grams of sodium citrate
may be substituted for the potiuuium
citrate."
(Sec. 111. 3011 a) of the Clran Air Act u
amended (42 U.S.C. 7111. 7G01 (a))).
CFR DOCJ9-10-17 Piled 1-11-79: 8:4r> ami
FEDERAL REGISTER, VOL. 44, NO. 9—FRIDAY, JANUARY
51
-------
ECHNICAL REPORT DATA
FPA
3. RECIPIENT'S ACC55SIO>NO.
. \ C 5 \* 5 ~ I T L £
A STUDY TO IMPROVE EPA METHODS 15 AND 16 FOR REDUCED
SULFUR COMPOUNDS
5. REPORT DATE
April 1980
6. PERFORMING ORGANIZATION CODE
Ao . -OR»S;
Henry F. Hamil and Nollie F. Swynnerton
8. PERFORMING ORGANIZATION REPORT NO.
9. PER FOR.VIs. G ORGANIZATION NAME AND ADORE S3
Southwest Research Institute
6220 Culebra Road
San Antonio, TX 78284
10. PROGRAM ELEMENT NO.
A09A1D
11. CONTRACT/GRANT NO.
68-02-2489
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Monitoring System Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA 600/08
15. SUPPLEMENTARY NOTES
To be published as an Environmental Monitoring Series report.
EPA source test methods for reduced sulfur compounds, Method 15 for Claus
sulfur recovery plants and Method 16 for Kraft pulp mills have been evaluated,
and information is provided for the user. Techniques and procedures for the gas
chromatographic measurement of hydrogen sulfide, carbonoxysulfide, carbon disulfide,
methylmercaptan, dimethylsulfide and dimethyldisulfide were studied. Absorption of
these species on the surfaces of the chromatographic system was found to be the main
source of imprecision and inaccuracy in the analysis. Permeation devices containing
the above sulfur compounds were found to permeate at uniform rates after one year of
use. Aluminum cylinders containing compressed gas mixtures of the compounds under
investigation were analyzed for four,months. Results showed them to be stable in
some instances and to be promising condidates for quality assurance materials
Comparison of an electrolytic conductivity detector with a flame photometric detector
showed the former to be valuable for the analysis of reduced sulfur compounds under
laboratory conditions.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI l-'icki/'Group
air pollution
gas sampling
Kraft pulp mills
Claus sulfur recovery plants
reduced sulfur compounds
gas chromatography
43F
68A
;.-, STATEV£\T
RELEASE TO PUBLIC
EPA Fsrm 22:0-1 (9-73)
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Unclassified
21. NO. OF PAGES
52
20. SECURITY CLASS (This page)
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