The 20m-tall column, which will remove carbon dioxide from the raw Kapuni gas stream, was shipped from supplier ASC Engineering Pty in Adelaide last week and will be installed this week. The new equipment is expected to be fully operational and tied into the plant's control systems by December.

NGC project manager Geoff Eaton said the column was sourced from Australia because ASC Engineering offered the best delivery timeframe, which was important as NGC was looking to move to maximum gas treatment capability as soon as possible.

Last January NGC said it would spend over $NZ7 million returning the plant to full processing capacity, recommissioning of one of the plant's three process trains and increasing on-site LPG storage by 100 tonnes. A new demineralised water plant has since been included.

The new absorber column will also improve the plant's flexibility. The existing plant is unique in New Zealand for its ability to process the 42% carbon dioxide content of Kapuni gas and the new column will also be able to treat gas with a carbon dioxide content as low as 13%.

This, combined with the plant's existing ability to process gases with no carbon dioxide, positions it to accept gases from other fields, such as Kahili, that may require treatment before delivery into the retail market.

There will be a heavier reliance on Kapuni and other smaller fields in New Zealand as the faltering Maui field continues its rapid decline.

The additional LPG storage bullet, which is expected to be installed by next February-March, will almost double existing plant storage capacity to 230 tonnes. It will also provide improved storage buffering for the New Zealand LPG market that is expanding by about 12% per annum.

In 1995, two of the processing trains were upgraded as part of a three-year, $NZ25 million plant refurbishment project. However, the third train had not been used because of the retail market supply environment.