ENV-95-162 FCC OFF-GAS CLEANING AT THE VALERO REFINERY CORPUS CHRISTI, TEXAS

Description:

The HOC flue gas train includes a tertiary cyclone with fourth stage cyclone, followed by a 36,000 HP power recovery turbo-expander, a flue gas cooler, a wet gas scrubber and a stack. Originally, the HOC, designed by M. W. Kellogg, was equipped with a horizontal Weir scrubber using a citrate process for control of SO, and particulate emissions and production of elemental sulfur. Because the citrate process did not perform at the expected reliability, the wet scrubber was soon converted to a straight caustic soda scrubber for absorption of SO, and discharge of a purge containing sodium sulfite was routed to the refinery waste water treatment (WWT) facility. The citrate regenerators were converted to purge water oxidizers for conversion of sodium sulfite to sodium sulfate.