Royal Dutch Shell's new 800,000 ton-per-year (tpy) ethylene cracker in Singapore has resumed operations, after a brief disruption caused by a power trip, industry sources said on Wednesday.It was unclear if the plant, which flared on Tuesday, was partially or completely shut, but it resumed operations around late on Wednesday, they added. "It was down for only a bit," said a Southeast Asia-based industry source.

This was sooner than expected as traders had earlier expected it to be shut for around three days.

When contacted, a Shell spokeswoman said: "We do not comment on operational matters."

The company earlier said in a statement that the "flare system at Shell's Pulau Bukom manufacturing site was activated in the afternoon of Aug. 3, 2010 due to an unplanned disruption to a process unit.

"There is no cause for alarm as the flare system is a major safety device. The rest of the operations was not affected." The spokeswoman did not elaborate if the flaring was related to the cracker.

Industry sources said the unit had been hit by occasional problems since it was commissioned in March and that some parts of it had to be shut during its four-month operation.

"The plant has been having operational problems since it started because the technology is quite new and the equipment is very sensitive. This time round, it is a trip but I'm not sure if the whole plant is shut or just partially," one source said.

Another source said: "There has been flaring since yesterday, but flaring happens even after a cracker is shut as the refiner needs to decompress or flush the unit lines."

The cracker, which was officially opened in May, has the option to use a range of feedstocks other than naphtha, and these include liquefied petroleum gas and heavy liquid hydrocarbon such as hydrowax. The brief outage did not affect naphtha market sentiment, with cracks rising to a two-session high on Wednesday at $72.23 a ton premium after Formosa, Asia's top spot naphtha buyer, sought volumes in a tender closing on Thursday.