Biogas Compressors Project in New Zealand

A Wittig rotary vane compressor ROW 120 G was installed at the Bromley WWTW in Christchurch, New Zealand to replace troublesome reciprocating compressors.

The compressor package takes biogas from anaerobic digesters, via a sand filter and small gas holder and feeds the gas to the power generation room adjacent where there are 3 biogas powered generator sets, 1 large Waukesha and 2 smaller Allen generators with a total installed power output of 2.4 MW.

Actual electricity output averages 1.24 MW burning 730 m3/hr of biogas.

The compressor package comprises inlet liquid separator, inlet filter, Wittig ROW 120 G gas compressor with 55 kW variable speed drive motor, discharge cooler and condensate separator. A separate control panel with the Variable Speed Drive is mounted within the generator building. The gas is fed to the generator room at 3.5 bar (g) to suit the Waukesha engine and at reduced pressure to suit the 2 Allen generator sets.