HOUSTON, April 29 Valero Energy Corp's
292,000 barrel per day (bpd) Port Arthur, Texas, refinery
restarted a hydrocracking unit, according to a notice the
refinery filed with Texas pollution regulators on Saturday.
Valero has been performing a catalyst change on a
hydrocracking unit at the refinery. A hydrocracker uses hydrogen
to boost motor fuel production, especially diesel.
The start-up triggered flaring at the refinery, according to
the notice filed with the Texas Commission on Environmental
Quality. Sulfur dioxide, nitrogen oxide, hydrogen sulfide and
volatile organic compounds beyond the refinery's permitted
limits were released during the start-up.