METHOD
16 - SEMICONTINUOUS DETERMINATION OF SULFUR EMISSIONS FROM STATIONARY SOURCES
NOTE: This method does not include all of the
specifications (e.g.,
equipment and supplies) and procedures (e.g., sampling and analytical) essential to its
performance. Some material is incorporated by reference from other methods in
this part. Therefore, to obtain reliable results, persons using this method
should have a thorough knowledge of at least the following additional test
methods: Method 1, Method 4,
Method 15, and Method 16A.
4.2 Carbon Monoxide
(CO) and Carbon Dioxide (CO2).
8.0 Sample Collection,
Preservation, Storage, and Transport.
10.0 Calibration and
Standardization.
12.0 Data Analysis and
Calculations.
14.0 Pollution
Prevention. [Reserved]
15.0 Waste Management.
[Reserved]
17.0 Tables, Diagrams,
Flowcharts, and Validation Data.
1.0 Scope and Application.
1.1 Analytes.
1.2 Applicability.
This method is
applicable for the determination of total reduced sulfur (TRS) compounds from
recovery furnaces, lime kilns, and smelt dissolving tanks at Kraft pulp mills
and fuel gas combustion devices at petroleum refineries.
NOTE: The method described below uses the principle of
gas chromatographic (GC) separation and flame photometric detection (FPD).
Since there are many systems or sets of operating conditions that represent
useable 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 calibration precision and sample line
loss criteria are met.
1.3 Data Quality Objectives.
Adherence to the requirements
of this method will enhance the quality of the data obtained from air pollutant
sampling methods.
2.0 Summary of Method.
2.1 A gas sample is
extracted from the emission source and an aliquot is analyzed for hydrogen
sulfide (H2S), methyl mercaptan (MeSH), dimethyl sulfide
(DMS), and dimethyl disulfide (DMDS) by GC/FPD. These four compounds are known
collectively as TRS.
3.0 Definitions. [Reserved]
4.0 Interferences.
4.1 Moisture.
Moisture condensation
in the sample delivery system, the analytical column, or the FPD burner block
can cause losses or interferences. This is prevented by maintaining the probe,
filter box, and connections at a temperature of at least 120 ûC (248 ûF). Moisture
is removed in the SO2
scrubber and heating the sample
beyond this point is not necessary when the ambient temperature is above 0 ûC
(32 ûF). Alternatively, moisture may be 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.
4.2 Carbon Monoxide (CO) and Carbon Dioxide (CO2).
CO and CO2 have a substantial desensitizing effect on the flame photometric
detector even after dilution. Acceptable systems must demonstrate that they
have eliminated this interference by some procedure such as eluting these
compounds before any of the compounds to be measured. Compliance with this
requirement can be demonstrated by submitting chromatograms of calibration
gases with and without CO2
in the diluent gas. The CO2 level should be approximately 10 percent for the case with CO2 present. The two chromatograms should show agreement within the
precision limits of Section 10.2.
4.3 Particulate Matter.
Particulate matter in
gas samples can cause interference by eventual clogging of the analytical
system. This interference is eliminated by using the Teflon filter after the
probe.
4.4 Sulfur Dioxide (SO2).
Sulfur dioxide is not
a specific interferent but may be present in such large amounts that it cannot
effectively be separated from the other compounds of interest. The SO2 scrubber described in Section 6.1.3 will
effectively remove SO2
from the sample.
5.0 Safety.
5.1 Disclaimer.
This method may
involve hazardous materials, operations, and equipment. This test method may
not address all of the safety problems associated with its use. It is the
responsibility of the user of this test method to establish appropriate safety
and health practices and determine the applicability of regulatory limitations
prior to performing this test method.
5.2 Hydrogen Sulfide.
A flammable,
poisonous gas with the odor of rotten eggs. H2S is
extremely hazardous and can cause collapse, coma, and death within a few
seconds of one or two inhalations at sufficient concentrations. Low
concentrations irritate the mucous membranes and may cause nausea, dizziness,
and headache after exposure.
6.0 Equipment and Supplies.
6.1. Sample Collection.
The following items
are needed for sample collection.
6.1.1 Probe.
Teflon or
Teflon-lined stainless steel. The probe must be heated to prevent moisture
condensation. It must be designed
to allow calibration gas to enter the probe at or near the sample point entry.
Any portion of the probe that contacts the stack gas must be heated to prevent
moisture condensation. Figure 16-1 illustrates the probe
used in lime kilns and other sources where significant amounts of particulate
matter are present. The probe is designed with the deflector shield placed
between the sample and the gas inlet holes to reduce clogging of the filter and
possible adsorption of sample gas. As an alternative, the probe described in Section 6.1.1 of Method 16A having a nozzle
directed away from the gas stream may be used at sources having significant
amounts of particulate matter.
6.1.2 Particulate Filter.
50-mm Teflon filter
holder and a 1- to 2-micron porosity Teflon filter (available through Savillex
Corporation, 5325 Highway 101, Minnetonka, Minnesota 55343). The filter holder
must be maintained in a hot box at a temperature of at least 120 ûC (248 ûF).
6.1.3 SO2 Scrubber.
Three 300-ml Teflon
segmented impingers connected in series with flexible, thick-walled, Teflon
tubing. (Impinger parts and tubing available through Savillex.) The first two
impingers contain 100 ml of citrate buffer and the third impinger is initially
dry. The tip of the tube inserted into the solution should be constricted to
less than 3 mm (1/8 in.) ID and should be immersed to a depth of at least 5 cm
(2 in.). Immerse the impingers in an ice water bath and maintain near 0 ûC (32
ûF). The scrubber solution will normally last for a 3-hour run before needing
replacement. This will depend upon the effects of moisture and particulate
matter on the solution strength and pH. Connections between the probe,
particulate filter, and SO2
scrubber must be made of Teflon and
as short in length as possible. All portions of the probe, particulate filter,
and connections prior to the SO2 scrubber (or
alternative point of moisture removal) must be maintained at a temperature of at
least 120 ûC (248 ûF).
6.1.4 Sample Line.
Teflon, no greater
than 1.3 cm (1/2 in.) ID. Alternative materials, such as virgin Nylon, may be
used provided the line loss test is acceptable.
6.1.5 Sample Pump.
The sample pump must
be a leakless Teflon-coated diaphragm type or equivalent.
6.2 Analysis.
The following items
are needed for sample analysis:
6.2.1 Dilution System. Needed only for high
sample concentrations. The dilution system must be constructed such that all
sample contacts are made of Teflon, glass, or stainless steel.
6.2.2 Gas
Chromatograph. The gas chromatograph must have at least the following
components:
6.2.2.1 Oven. Capable
of maintaining the separation column at the proper operating temperature ± 1 ûC
(2 ûF).
6.2.2.2 Temperature
Gauge. To monitor column oven, detector, and exhaust temperature ± 1 ûC (2 ûF).
6.2.2.3 Flow System.
Gas metering system to measure sample, fuel, combustion gas, and carrier gas
flows.
6.2.2.4 Flame
Photometric Detector.
6.2.2.4.1
Electrometer. Capable of full scale amplification of linear ranges of 10-9 to 10-4 amperes
full scale.
6.2.2.4.2 Power
Supply. Capable of delivering up to 750 volts.
6.2.2.4.3 Recorder.
Compatible with the output voltage range of the electrometer.
6.2.2.4.4 Rotary Gas
Valves. Multiport Teflon-lined valves equipped with sample loop. Sample loop
volumes must be chosen to provide the needed analytical range. Teflon tubing
and fittings must be used throughout to present an inert surface for sample
gas. The gas chromatograph must be calibrated with the sample loop used for
sample analysis.
6.2.3 Gas
Chromatogram Columns. The column system must be demonstrated to be capable of
resolving the four major reduced sulfur compounds: H2S, MeSH, DMS, and DMDS. It must also demonstrate freedom from known
interferences. To demonstrate that adequate resolution has been achieved, submit a chromatogram of a calibration
gas containing all four of the TRS compounds in the concentration range of the
applicable standard. Adequate resolution will be defined as base line
separation of adjacent peaks when the amplifier attenuation is set so that the
smaller peak is at least 50 percent of full scale. Baseline separation is
defined as a return to zero ±5 percent in the interval between peaks. Systems
not meeting this criteria may be considered alternate methods subject to the
approval of the Administrator.
6.3 Calibration.
A calibration system,
containing the following components, is required (see Figure
16-2).
6.3.1 Tube Chamber.
Chamber of glass or Teflon of sufficient dimensions to house permeation tubes.
6.3.2 Flow System. To
measure air flow over permeation tubes at ±2 percent. Flow over the permeation
device may also be determined using a soap bubble flow meter.
6.3.3 Constant
Temperature Bath. Device capable of maintaining the permeation tubes at the
calibration temperature within 0.1 ûC (0.2 ûF).
6.3.4 Temperature
Gauge. Thermometer or equivalent to monitor bath temperature within 1 ûC (2
ûF).
7.0 Reagents and Standards.
7.1 Fuel. Hydrogen (H2), prepurified grade or better.
7.2 Combustion Gas.
Oxygen (O2) or air, research purity or better.
7.3 Carrier Gas.
Prepurified grade or better.
7.4 Diluent (if required).
Air containing less than 50 ppb total sulfur compounds and less than 10 ppmv
each of moisture and total hydrocarbons.
7.5 Calibration
Gases.
7.5.1 Permeation
tubes, one each of H2S, MeSH, DMS, and DMDS, gravimetrically
calibrated and certified at some convenient operating temperature. These tubes
consist of hermetically sealed FEP Teflon tubing in which a liquefied gaseous
substance is enclosed. The enclosed gas permeates through the tubing wall at a
constant rate. When the temperature is constant, calibration gases 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.
7.5.2 Cylinder Gases.
Cylinder gases may be used as alternatives to permeation devices. The gases
must be traceable to a primary standard (such as permeation tubes) and not used
beyond the certification expiration date.
7.6 Citrate Buffer
and Sample Line Loss Gas. Same as Method 15,
Sections 7.6 and 7.7.
8.0 Sample Collection, Preservation, Storage, and
Transport.
Same as Method 15, Section 8.0, except that the references
to the dilution system may not be applicable.
9.0 Quality Control.
10.0 Calibration and Standardization.
Same as Method 15, Section 10.0, with the following
addition and exceptions:
10.1 Use the four
compounds that comprise TRS instead of the three reduced sulfur compounds
measured by Method 15.
10.2
Flow Meter. Calibration before each test run is recommended, but not required;
calibration following each test series is mandatory. Calibrate each flow meter
after each complete test series with a wet-test meter. If the flow measuring
device differs from the wet-test meter by 5 percent or more, the completed test
runs must be voided. Alternatively, the flow data that yield the lower flow
measurement may be used. Flow over the permeation device may also be determined
using a soap bubble flow meter.
11.0 Analytical Procedure.
Sample collection and
analysis are concurrent for this method (see Section 8.0).
12.0 Data Analysis and Calculations.
12.1 Concentration of
Reduced Sulfur Compounds. Calculate the average concentration of each of the
four analytes (i.e., DMDS,
DMS, H2S, and MeSH) over the sample run (specified in Section 8.2 of Method 15 as 16 injections).
where:
Si = Concentration of any reduced sulfur compound from the ith sample injection, ppm.
C = Average
concentration of any one of the reduced sulfur compounds for the entire run,
ppm.
N = Number of injections
in any run period.
12.2 TRS
Concentration. Using Equation 16-2, calculate the TRS concentration for each
sample run.
where:
CTRS = TRS concentration, ppmv.
CH2S = Hydrogen sulfide concentration, ppmv.
CMeSH = Methyl mercaptan concentration, ppmv.
CDMS = Dimethyl sulfide concentration, ppmv.
CDMDS = Dimethyl disulfide concentration, ppmv.
d = Dilution factor,
dimensionless.
12.3 Average TRS
Concentration. Calculate the average TRS concentration for all sample runs
performed.
where:
Average TRS = Average
total reduced sulfur in ppm.
TRSi = Total reduced sulfur in ppm as determined by Equation 16-2.
N = Number of
samples.
Bwo = Fraction of volume of water vapor in the gas
stream as determined by Method 4 -Determination of Moisture in Stack Gases.
13.0 Method Performance.
13.1 Analytical
Range. The analytical range will vary with the sample loop size. Typically, the
analytical range may extend from 0.1 to 100 ppmv using 10- to 0.1-ml sample
loop sizes. This eliminates the need for sample dilution in most cases.
13.2 Sensitivity.
Using the 10-ml sample size, the minimum detectable concentration is
approximately 50 ppb.
14.0 Pollution Prevention. [Reserved]
15.0 Waste Management. [Reserved]
16.0 References.
1. O'Keeffe, A.E.,
and G.C. Ortman. "Primary Standards for Trace Gas Analysis."
Analytical Chemical Journal, 38,76. 1966.
2. Stevens, R.K.,
A.E. O'Keeffe, and G.C. Ortman. "Absolute Calibration of a Flame
Photometric Detector to Volatile Sulfur Compounds at Sub-Part-Per-Million Levels."
Environmental Science and Technology, 3:7. July 1969.
3. Mulik, J.D., R.K.
Stevens, and R. Baumgardner. "An Analytical System Designed to Measure
Multiple Malodorous Compounds Related to Kraft Mill Activities." Presented
at the 12th Conference on Methods in Air Pollution and Industrial Hygiene
Studies, University of Southern California, Los Angeles, CA. April 6-8, 1971.
4. Devonald, R.H.,
R.S. Serenius, and A.D. McIntyre. "Evaluation of the Flame Photometric
Detector for Analysis of Sulfur Compounds." Pulp and Paper Magazine of
Canada, 73,3. March 1972.
5. Grimley, K.W.,
W.S. Smith, and R.M. Martin. "The Use of a Dynamic Dilution System in the
Conditioning of Stack Gases for Automated Analysis by a Mobile Sampling
Van." Presented at the 63rd Annual APCA Meeting, St. Louis, MO. June
14-19, 1970.
6. General Reference.
Standard Methods of Chemical Analysis, Volumes III-A and III-B Instrumental
Methods. Sixth Edition. Van Nostrand Reinhold Co.
17.0 Tables, Diagrams, Flowcharts, and Validation Data.
Figure
16-1. Probe used for Sample Gas Containing High Particulate Matter Loading.
Figure
16-2. Calibration System.
