SINGAPORE, March 28 (Reuters) - China's Rongsheng

Petrochemical, a major independent refiner, has

opened an office in Canada to buy Canadian crude and made its

first purchase from local producer Suncor Energy ( SU ), trade

sources said.

Rongsheng, China's largest independent refiner with capacity

of 40 million metric tons a year, or 800,000 barrels a day, has

become a regular buyer of the heavy sour Canadian crude since

the newly-expanded Trans-Mountain pipeline started operations

last May.

More Canadian crude is expected to flow into Asia this year,

as U.S. President Donald Trump threatens to impose a 10% import

tariff on its oil and gas.

Rongsheng's first purchase since opening the new office in

the western city of Calgary is for June-arrival crude cargo to

China, the sources said.

The company recently started buying Canadian crude on a

free-on-board (FOB) basis, while past purchases were mostly on a

delivered at place (DAP) basis, Wang Jie, its Calgary-based

general representative for Americas procurement and trading,

told Reuters.

An FOB contract normally allows buyers to re-sell cargoes,

affording more flexibility to redirect them, depending on market

conditions.

Rongsheng also buys Canadian crude from suppliers such as

Cenovus Energy ( CVE ), Canadian Natural Resources ( CNQ ),

ConocoPhillips ( COP ), BP and Shell, Wang said.

Wang, who founded and chaired PetroChina International

Canada Trading, an arm of state oil giant China National

Petroleum Corp (CNPC), joined Rongsheng in January, his LinkedIn

profile shows.

He was previously at Singapore-based Essence Energy.

"The company has always attached importance to the global

talent layout and continues to optimise team configuration

according to the needs of business development," Rongsheng said

in an email to Reuters.