HOUSTON – Using evidence rang- ing from cutting-edge engineering studies to a diagram of an industrial flare that he drew on a courtroom easel, Caltech-trained engineer Dr. Ranajit Sahu testified in U.S. District Court in Houston that Exxon routinely and drastically under-counts the amount of pollution emitted from flares at its Baytown refinery and chemical plant complex.
Factors such as crosswinds, and the amount of steam Exxon injects into flaming flares to reduce the formation of soot, can each cause dramatic reductions in combustion efficiency.
There are 26 elevated flares at the Baytown Complex that burn gases in open flames, much like gigantic Bunsen burners hundreds of feet high. These flares reduce explosion risks by burning off flammable gases generated, intentionally or unintentionally, during the refining process.
Dr. Sahu, an expert in flare combustion technology, testified in Environment Texas and Sierra Club’s Clean Air Act lawsuit that current state and federal regulations allow companies like Exxon to assume that 98% to 99% of the toxic gases sent to the flares are fully combusted—even though, in practice, such high levels of combustion are rarely achieved.
Factors such as crosswinds, and the amount of steam Exxon injects into flaming flares to reduce the formation of soot, can each cause dramatic reductions in combustion efficiency. “Over-steaming” can actually quench a flame completely, resulting in no emission control at all.
The practical import of this, Dr. Sahu explained to U.S. District Judge David Hittner, is that far more pollution is released from Exxon’s flares into the surrounding communities than Exxon reports.
Studies in which airplanes have flown over the Houston Ship Channel to directly measure pollutant concentrations have shown that actual emissions from flares are 10 or more times higher than what industry has reported.
And for the people who live in Baytown and other nearby communities, this means far higher levels of exposure to harmful pollutants whenever Exxon uses its flares during the hundreds of emission events that occur each year at the Baytown Complex.
