EPA Method 15 - H2S in Fuel Gases
- The sample is withdrawn directly from the source through heated line to the GC
- Analysis is semi-continuous with a snapshot every 5-20 minutes
- Method 15 requires a minimum of sixteen injections per test run
- Sample degradation issues are minimized by direct injection into the GC
- Direct injection is an excellent tool for tracking batch processes (unless the process changes can occur faster than the snapshot injection times)
- Dimethyl sulfide [(CH3)2S]
- Dimethyl disulfide [(CH3)2S2]
- Methyl mercaptan (CH4S)
- Hydrogen sulfide (H2S)
- Carbonyl sulfide (COS)
- Carbon disulfide (CS2)
- The lower range of this procedure is determined by the sampling system. This is generally about 0.5 ppmv.
- The upper limit is governed by the GC detector saturation or column overloading. The upper range can be extended by dilution interface sampling.
- Sample is withdrawn from the source and delivered continuously to the GC (similar to EPA Method 25A). A preferred sampling rate would yield a response time of less than one minute.
- All heated elements should be set to ~250oF;
- A test run consists of a minimum of 16 sample injections over:
- A minimum test time of three hours; and
- A maximum test time of six hours.
- Three test runs comprise a test series
- A slip-stream of the sample is drawn through a gas sampling valve on the instrument;
- An injection is performed by rotating the valve;
- Each injection will typically require 5-20 minutes to perform the analysis.
- A recovery study must be performed following sampling (similar to sample system bias);
- Performed by introducing sample to the probe tip and sampling similar to stack gases;
- Recovery is acceptable if bias is within +10% of the at-instrument value.
- Analysis results are typically not corrected for this recovery study results
- Short lengths of unheated lines can cause sample loss through condensation (e.g. 4" of teflon line). All sample delivery lines should be heated.
- No shipping issues - samples analyzed on-site.
- An excellent method for determining possible emissions from combustion of a given gaseous fuel such as refinery flare gases, anaerobic fuel, and others.
- None, please contact us if you have any questions!