Sorbent Traps for Continuous Measurement of Metal HAP Emissions

During this Phase I SBIR research project, Ohio Lumex will develop a sorbent trap method for continuous emissions monitoring of metal hazardous air pollutant (HAP) emissions. If this method is promulgated by EPA, it may also be used as an alternative to Method 29 for short-term testing. Metal HAP emissions from stationary sources are currently determined using emissions factors derived from intermittent stack testing measurements, input feed stream data, and plant operating parameters. Emissions factors may have significant uncertainty, particularly for sources where feed stream metal content is highly variable. Continuous measurements are needed to provide superior accuracy, but current technology is limited and cost prohibitive. The proposed technology would meet that need with repetitive in-stack sampling using paired sorbent traps with periodic analysis of time-integrated samples collected over a period of several days. This approach is analogous to Performance Specification 12B (PS 12B). Previous work by the Energy & Environmental Research Center (EERC) evaluated the feasibility of a sorbent trap reference method for metals. They determined the background metals on the sorbent were too high to accurately quantify several metals. EERC determined additional research was needed to evaluate other sorbent materials. This SBIR research will evaluate several sorbent materials and sampling durations of up to seven days. The proposed method is applicable to several industries. It will be designed with particular focus on continuous sampling for hazardous waste combustors, metal smelting operations, iron and steel production, secondary smelting facilities, and coal-fired power plants. However, if this method is ultimately promulgated by EPA, it could also be used for short-term (1-4 hours) sampling in lieu of EPA Method 29 for any facility that currently uses Method 29 (within applicable point source categories). The end user for this product depends on the application. For continuous measurements, plants (stationary sources) will purchase these traps for use in continuous sampling equipment. For short-term sampling as an alternative to Method 29, the customers are stack testing companies. Other customer categories will be discussed in the proposal. Continuous measurement of metal HAP emissions will improve EPA’s air emissions inventory and allow point sources to better understand their emissions. Sources that utilize control technologies to remove metals from the gas stream can use this information to optimize controls. For short-term testing, this method will benefit stack testers, who almost universally agree Method 29 is cumbersome, expensive, and hazardous.