ENV-17-21 Performance Review of Remote and Direct Flare Combustion Efficiency Monitor

Description:

Emissions from industrial flares make up a significant portion of the total industrial air emissions. In the Fact Sheet for the Proposed Petroleum Refinery Sector Risk and Technology Review and New Source Performance Standards, the U.S. Environmental Protection Agency (USEPA) stated that the proposed new standards for flares would reduce emissions of Volatile Organic Compounds (VOC) from flares in this sector by 33,000 tons per year1, which accounts for 63% of the total reductions in the proposed Refinery Sector rule. There are more flares in chemical and petrochemical sectors. In 2007, the Texas Commission on Environmental Quality (TCEQ) conducted a special emission inventory of Highly Reactive Volatile Organic Compounds (HRVOC) in Harris County for the period from February 1, 2006 to January 31, 2007. HRVOC is a subset of VOCs which represents the most potent ozone precursors. Results of this special emission inventory showed that the HRVOC emissions from flares were 1,469.5 tons out of a total HRVOC emission inventory of 2,433.4 tons in Harris County, i.e., flare emissions accounted for 60.8% of total HRVOC emissions2. If the combustion efficiency (CE) of flares is lower than expected (CE=96.5%, which is considered equivalent to a destruction efficiency of 98%), the emissions can be even higher. Research has shown that flare CE can be significantly lower than the expected or assumed value when the flare is over-assisted3. The problem is that flare CE is not monitored due to the lack of technology to do so.