M. Rodney Midgett

Sampling and Analysis Experiments for Improved Characterization of Products of Incomplete Combustion

Laboratory and field experiments were conducted to evaluate the volatile organic sampling train (VOST) methodology for the sampling and analysis of products of incomplete combustion (PICs). A pilot-scale incinerator was used to incinerate several volatile chlorinated organic compounds which were known to produce PICs. Approximately 300 ppm of 1,2-dichloroethane, 1,1,1-trichloroethane, and trichloroethene were individually incinerated at 700°C. Standard VOST sampling apparatus was used to collect samples for determinations of precision and for distributive volume-studies. A series of experiments was conducted to establish whether PICs were being formed at concentration levels which could be measured by the VOST methodology. Samples were collected at 1 L/ min for 20 min with standard pairs of Tenax-Tenax/charcoal cartridges. The major PICs found were vinyl chloride from 1,2-dichloroethane, 1,1-dlchloroethene from 1,1,1-trichloroethane, and carbon tetrachloride from trichloroethene. Chloromethane was also fo...

Integrated sampling and analysis methods for determining NO/SUB/x emissions at electric utility plants

Two integrated sampling and analysis methods for determining NO/sub x/ emissions in electric utility plants were developed and field tested. The collection systems consist of: a 4.0% potassium permanganate-2.0% sodium hydroxide solution in restricted-orifice impingers, and a 5A/sup 0/ molecular sieve in midget impingers. Sampler analysis is accomplished by a colorimetric or ion-chromatographic procedure with the alkaline-permanganate method and by a colorimetric procedure with the molecular seive method. The alkaline-permanganate method gives excellent agreement with the EPA reference method, Method 7, for NO/sub x/ measurements. The molecular sieve method shows a significant negative bias relative to Method 7. It is anticipated that the permanganate methods will be proposed as alternates to Method 7, for NO/sub x/ determinations, under the EPA New Source Performance Standards.

An Evaluation of the Semi-VOST Method for Determining Emissions from Hazardous Waste Incinerators

The Semi-Volatile Organic Sampling Train method was investigated to determine its reliability and to determine the bias and precision of the method when used to determine emissions from hazardous waste incinerators. Experiments showed that the matrix and sampling variables usually involved in sampling emissions from a hazardous waste incinerator had no significant effect on the recovery of 11 different organic compounds. Significant losses of the sampled compounds can occur during sample preparation. The degree of loss appears to be directly related to the compounds, vapor pressure. These losses can be corrected for by adding deuterated surrogates to the sample and analyzing the surrogates along with the native compounds. The bias determination was based on dynamic spiking of the sampling train with five deuterated organic compounds selected from Appendix VIII of the Resource Conservation and Recovery Act regulations. The results show biases of from -1 ± 8 percent to -18 ± 27 percent for chlorinated and n...

Determination of high sulfur dioxide concentrations and carbon dioxide in electric utility plants by alkaline permanganate sampling and ion chromatography

A manual 24-h integrated method for determining high concentrations of SO/sub 2/ and CO/sub 2/ in electric utility plants was field-tested upstream from an SO/sub 2/ control system. Samples were collected in an alkaline, potassium-permanganate solution contained in restricted-orifice impingers. Samples were analyzed by ion chromatography. The SO/sub 2/ collection efficiency was 84.6 +/- 4.2 (5.0 percent) relative to an independent continuous monitoring system; the CO/sub 2/ determination was unbiased provided that the sample flow rate was maintained below 40 cm/sup 3//min. The relative standard deviation for the SO/sub 2/ and CO/sub 2/ determinations was 5 and 2 percent, respectively. The method, when combined with earlier work downstream from a flue gas desulfurization systems, can be used for determining the efficiency of a flue gas desulfurization system. However, the upstream method may be biased low by approximately 10 percent.

Validation Studies of the Protocol for theVolatile Organic Sampling Train

The measurement of volatile organic emissions from a hazardous waste incinerator is one of the more difficult source testing problems. Specific compounds called principal organic hazardous constituents (POHC) are to be identified and quantified at levels of 0.5 to 100 ppb in hot, wet incinerator exhaust gas, which may also contain high particulate and acid levels. The Volatile Organic Sampling Train (VOST) Protocol which describes the practices used by laboratories making these measurements allows for several alternative designs and operating procedures. Because its use is currently being recommended by regulatory agencies to measure emissions for compliance determinations, the VOST Protocol was subjected to a methods validation study. The VOST Protocol validation program consists of two phases: a laboratory validation and a field test validation. The laboratory validation examined the results of sampling six different POHCs at two different concentration levels, two tube configuration designs, two moistu...

Calibration and certification of audit devices for transmissometers

This paper describes the procedures followed by the US Environmental Protection Agency, Environmental Monitoring Systems Laboratory, Research Triangle Park, NC, to certify the correct opacity to the neutral density (ND) filters for calibration of transmissometers. The term neutral density is applied to filters that have the ability to attenuate an incident beam of radiation without altering its spectral distribution over the visible range (380-770 nm). The actual certification process involves the scanning of the ND filter over the visible light energy range using a spectrophotometer. For this purpose, a conventional Cary Model 14 spectrophotometer was obtained and modified to improve the method of recording and processing data. A system was installed that converts the analog response of the spectrophotometer to a digital signal, which is then computer processed and a certification report automatically generated. The procedures for scanning the filter and the calculation algorithms to compute the luminous transmittance were adapted from procedures used by the National Bureau of Standards (NBS).

The Collaborative Test of Method 6-B: Twenty-Four-Hour Analysis of SO2 and CO2

The results are presented from the collaborative test of EPA Method 6-B for the 24-h analysis of SO2, CO2, and emission rate. Using both the intermittent and continuous options of Method 6-B, nine laboratories simultaneously sampled the stack at a flue gas desulfurizing unit of a coal burning electric power plant. The precision and accuracy of the method was based on results of 145 24-h determinations performed by the collaborators over a five day period. The estimates of repeatability (or within laboratory precision) expressed as a percent of the overall averages were: SO2, 9.8%; CO2, 9.9%; and E.R. (emission rate as lbs SO2/106 Btu), 8.0%. The reproducibility (or between laboratory precision estimates) were: SO2, 12.9%; CO2, 13.2%; and E.R., 11.1 %. The relative accuracy of the collaborative test results was determined by comparing the results obtained by reference methods and the plant continuous monitor. This overall accuracy for SO2, CO2, and E.R. was within 3%. Further tests performed during the sam...

Precision estimates for epa test method 8—SO2 and H2SO4 emissions from sulfuric acid plants

Abstract The results from a collaborative test of the U.S. Environmental Protection Agency Test Method 8 are presented. In the collaborative test six laboratories simultaneously sampled the same stack at a sulfuric acid plant using two Method 8 sampling trains per laboratory. The collaborative test determined that the repeatability of the method was 7.61 mg sulfuric acid per m3 and 22.30 mg sulfur dioxide per m3. Similarly, the reproducibility of the method was 8.43 mg sulfuric acid per m3 and 31.10 mg sulfur dioxide per m3. The estimates of precision were determined to be independent of the pollutant concentration over the concentration range measured.