A chemical division of Occidental Petroleum reported intermittent flaring over an 11-hour span because of hard freeze conditions in the Houston area this week, according to a filing made public Thursday by the Texas Commission on Environmental Quality.
OxyVinyls said in the filing that hard freeze conditions caused process upsets at the company's 1.7 million mt/year ethylene dichloride plant in La Porte, Texas, that increased pressure and prompted flaring from valves on storage tanks shortly after midnight through late morning on Wednesday.
EDC is used to make vinyl chloride monomer, which in makes polyvinyl chloride, used to manufacture plastic pipes, vinyl siding, window frames and other plastics.
Crews made operational adjustments to lower pressure and stop the releases, the filing said.
A severe cold snap hit the Houston area, as well as southeast Texas and and coastal Louisiana, early Tuesday through Thursday, bringing sleet, light snow and ice to roadways and infrastructure.
By early Wednesday precipitation had ceased, but the region had one more night of below-freezing temperatures before conditions improved Thursday.
