Royal Dutch Shell will be able to operate its Singapore oil refinery at full 500,000 barrel-per-day (bpd) capacity after a revamp, a company official said on Tuesday.

Shell has built two new units and revamped existing ones at its Singapore refinery to widen feedstock choices for its new ethylene cracker, said Pieter Eijsberg, deputy venture director of Shell Eastern Petrochemicals Complex said at the official opening of the new petrochemical complex in Singapore. The multi-billion dollar petrochemical project is Shell's largest downstream investment in Asia, the company said.

In March, Shell started operations at the new 800,000 ton-per-year (tpy) cracker on Bukom island and it is running smoothly.

"The timing of petrochemical venture startup is extremely good as the market is picking up again," Shell CEO Peter Voser told reporters.

The complex will add to rising supply in Asia where ethylene capacity will rise by 14%, or more than 6 million tpy in 2010 while Middle Eastern plants, brought on stream last year, are ramping up output. The glut may force petrochemical makers to cut runs from the second half of this year after producing at full tilt since 2009. China will account for more than a third of the additions, reducing its huge appetite for imports, analysts have said.

The cracker has the options to use a range of feedstock other than naphtha, and these include liquefied petroleum gas and heavy liquid hydrocarbon such as hydrowax. A high vacuum unit has been added to provide feedstock to the refinery's hydrocracker which will then produce hydrowax for the new ethylene cracker, Eijsberg said.

Shell has also built a new sulphur-recovery unit which allows the refinery to process more sour crude, he said. The project also included a 750,000 tpy monoethylene glycol (MEG) unit on nearby Jurong island which started up in December last year. MEG is used to produce consumer and industrial goods including polyester fibres for clothing and furnishings, PET bottles, film and coolants.