PetroChina Co Ltd  plans to shut down a 90,000-barrel-per-day (bpd) crude distillation unit (CDU) at its largest Dalian refinery for one-month maintenance around April 2013, an industry source said on Thursday.

The Dalian refinery has three CDUs with total crude processing capacity of 410,000 bpd.

Crude throughput at the refinery is expected to be nearly 340,000 bpd this year, the source said.