Lyondell Basell Industries is expected to ramp up production at its 263,776 barrel per day (bpd) Houston refinery after restarting the small crude distillation unit following a month-long outage, Gulf Coast market sources said.

Energy industry intelligence service Genscape said the 120,000 bpd Unit 536 CDU restarted. Unit 536 was shut on April 11 to repair leaks on the attached 91,000 bpd vacuum distillation unit. The VDU also restarted, Genscape said. A Lyondell spokeswoman declined to discuss operations at the refinery. The first attempt to restart Unit 536 failed, sources told Reuters .

The refinery’s production fell to 85,000 bpd, or 32 per cent of capacity, after the 91,000 bpd VDU attached to the 147,000 bpd Unit 537 CDU was shut on April 15 to repair leaks. That came after the Unit 536 shutdown and a 42,000 bpd coker at the refinery was idled for up to three months after a massive fire on April 8. The Unit 537 VDU restarted on May 1. With the refinery’s CDUs and VDUs back in operation, Lyondell hopes to reach a crude oil intake of up to 200,000 bpd.

CDUs do the initial refining of crude oil coming into the refinery and provide feedstock to all other production units. VDUs refine residual crude produced by the CDUs, increasing the yield from a barrel of oil. Coking units do the final refining of residual crude, converting the gunky material into either feedstock for motor fuels or into petroleum coke, which is a coal substitute.