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.

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     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.

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 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.

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TO3
                        H2S, ppm
     FIGURE 1. H,S CALIBRATION CURVES AT TWO VOLUMES
                        10

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  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

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   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

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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

-------
             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

-------
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

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                                  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

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                                 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

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                            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

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                 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

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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

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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

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                                    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)
                                              19. SECURITY CLASS I i'/lis Repurt/

                                                Unclassified	
                                                                        21. NO. OF PAGES
                                       52
20. SECURITY CLASS (This page)
   Unclassified

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