Asia's biggest oil and gas producer swung to a 27.7 billion yuan ($4.28 billion) first-quarter net profit, having posted a loss in the same period last year, and announced that it is setting up a new investment vehicle with a focus on strategic assets and low-carbon projects.

The new firm, CNPC Kunlun Capital Company, is 51% owned by PetroChina parent China National Petroleum Corp, 29% by PetroChina and 20% by CNPC Capital, with registered capital of 10 billion yuan.

PetroChina's first-quarter revenue was up 8.4% at 551.9 billon yuan, it said in a filing to the Hong Kong Stock Exchange.

Oil and gas output grew 0.8% to 417.1 million barrels of oil equivalent, with crude oil production down 4.9% while gas output was up 8% at 1.17 trillion cubic feet.

Refinery throughput rose 7.8% to about 3.31 million barrels per day, reversing close to a 10% drop a year earlier.

Its domestic gas sales rallied nearly 15% and refined fuel surged 20.9% as Chinese fuel demand rebounded in tandem with robust economic growth.

($1 = 6.4665 Chinese yuan renminbi)

(This story has been corrected to reflect that Q1 profit was not the best in seven years)

(Reporting by Chen Aizhu in Singapore and Muyu Xu in Beijing; editing by David Goodman)