Feb 19, 2012:

Exxon Mobil Corp's 344,500 barrel per day (bpd) Beaumont, Texas, refinery returned a coking unit to normal operations on Sunday following a compressor malfunction, according to a notice the refinery filed with Texas pollution regulators. A coker increases the amount of refinable material from a barrel of crude oil and produces petroleum coke, a coal substitute.

The Beaumont refinery also reported a malfunction on the coking unit on Friday and Saturday, according to notices filed with state and federal regulators.

By Reuters