A $40 million plant which will purify and recycle 50,000 tonnes of carbon dioxide each year will be run by one person.

BOC New Zealand yesterday opened its CO2 "capture and purification plant" at Marsden Pt Oil Refinery, which will convert about 6 per cent of the refinery's waste CO2 into a product used in food processing, beverage, wine, meat and dairy industries.

Despite the operation's scale, production supervisor Nick Mulligan will be the plant's sole staffer, in charge of maintenance and overseeing the preparation of upwards of 20 18-tonne tankers each week.

"Basically we buy in the hot, wet, dirty CO2 and clean, dry and liquefy it," Mr Mulligan said. The CO2 gas was washed before being transitioned to a liquid using ammonia.

Advertisement

The plant had been under construction for just over a year, with the opening attended by dignitaries including Whangarei MP Dr Shane Reti, Northland MP and NZ First Leader Winston Peters, Labour MP David Parker, and Whangarei Mayor Sheryl Mai.

Refining NZ spokesman Greg McNeill said the facility was part of the refinery's goal to reduce its carbon footprint. CO2 was a byproduct of the manufacture of hydrogen and the refinery produces about 140 tonnes of hydrogen a day. Some of this CO2 was sold to other outlets, but piping laid between the main refinery and new plant meant it was now mainlined to BOC.

Mr McNeill said the plant was also beneficial to the company as it provided a predictable revenue stream, alongside Refining NZ's core operations which were subject to volatile refining margins and foreign exchange rates.

BOC South Pacific managing director Colin Isaac said the plant captured four times more CO2 than any other facility in New Zealand.

Food grade CO2's most common uses included drink carbonation, modified atmosphere food packaging and chilling.

Australian-owned BOC had funded the plan and was leasing the land from Refining NZ.