China National Petroleum Corp. processed 147 million metric tons of crude oil last year, the State-owned Assets Supervision and Administration Commission said Monday.

That is 2.9 million barrels a day and a 1.7% increase from 2011 for the country's largest energy producer by output.

More ethylene production at its plants in Daqing and
Fushun are partly responsible for the increase, the commission said in the statement dated Friday. A 5-million-ton-a-year expansion to a refinery at Hohhot completed last year also helped.

CNPC's total processing volume represented about 31% of Chinese refinery throughput in 2012, according to Dow Jones Newswires calculations. Chinese refiners processed 467.91 million tons of crude oil in 2012, up 3.7% on year, data from the National Bureau of Statistics showed Friday.