Mercury traces in natural gas supplied in Singapore

Ronnie Lim, Business Times 9 Mar 10;

(SINGAPORE) Singapore is looking at putting safeguards in place after traces of mercury, a toxic metal, were found in Indonesian natural gas imported from West Natuna last June.

While that was apparently an isolated incident with the low mercury levels detected posing no real danger to public health, the authorities are taking no chances given that gas is a leading energy fuel here.

The Energy Market Authority (EMA) is getting a consultant to assess the impact, if any, the toxic metal has on pipeline operators as well as end-users like the power stations and petrochemical plants and also the public (which uses town gas for cooking and heating purposes). It also wants the consultant to identify measures, if needed, to mitigate this.

This is because mercury, which is found organically-bound in natural gas from the gasfield, can potentially damage plant and equipment like heat exchangers, or affect workers exposed to it during maintenance operations.

BT understands, however, that the mercury found in the Natuna gas piped in by Sembcorp last June was low-level and was reported by its upstream gas supplier.

Gas Supply Pte Ltd (GSPL), the other Indonesian gas importer which sources its gas from South Sumatra, said that it has so far not encountered any mercury issues.

'But it's not an uncommon problem as, for instance, the Arun gasfield at the end period also had a lot of mercury coming out,' said GSPL's CEO Tan Chin Tung.

The mercury, common in natural gas production, can potentially damage plant and equipment, although it is normally filtered out at the gasfield, he said.

The June incident also doesn't have an impact on towngas supplied to homes and businesses here, as City Gas (the towngas supplier) gets its natural gas supplies from GSPL, and converts this into towngas, which is essentially hydrogen and carbon monoxide, added Mr Tan.

Nevertheless, EMA is not taking any chances.

With natural gas coming in from both Indonesia's West Natuna and South Sumatra, and also Malaysia, it wants the consultant to study the gas system here to identify the locations where mercury can accumulate. Besides, liquefied natural gas supplies will also start being shipped in here, starting mid-2013.

EMA also wants the consultant to assess the existing government regulations here (from the Manpower Ministry, National Environment Agency and Agri-Food & Veterinary Authority) regarding exposure to mercury by workers during operations and maintenance.

The consultant will also look at potential contamination of food or food-related products arising from gas usage, and physical damage to gas network components that may be vulnerable.

Another area covers flue gas emission arising from end-users' operations and mercury content released to the ambient environment due to gas leak or pipeline damage.

'The consultant shall recommend, with a cost-benefit analysis, a safe limit for the mercury content of gas that can be introduced into the Singapore gas system and any mitigating measures which need to be taken,' EMA said of the eight-month study.