The non-dispersive diffusion system features a Liqui-Cel®’ Extra-Flow™ Membrane Contactor manufactured by Celgard, Inc. of
At the Mansfield Brewery, the marketdriven purpose of nitrogen introduction was to lower CO2 content, which was necessary to create a “smooth” beer – a “keg” beer that would mimic “cask-conditioned” beers, but without losing the “head” characteristic of keg beers.
Mike Cleator, the brewery’s chief engineer, explained that dispersive direct-injection technology already available for nitrogen introduction was considered disadvantageous. Direct injection would have introduced highly undesirable turbulence that would have knocked CO2 out of solution, because in order to make the nitrogen dissolve with any speed, pressure would have to be raised up to 8 – 9 bar(132 psi). With the Celgard technology, nitrogen could be introduced at low pressure – typically 30 –
45 psi – a level that is actually lower than the 60 psi pressure needed to move the beer around.
According to Mike Cleator, capital cost savings were a significant advantage for the installed system, which has been performing well.
The cost for the non-dispersive nitrogen diffusion system, consisting of the Celgard membrane, an Orbisphere 2-channel CO2/ N2 meter, a control panel, and a membrane cleaning tank with pump & heater, came in at about $64,000. By comparison, off-theshelf cost for a dispersive direct-injection system would have been about $144,000. The system has now been operating successfully since May, 1997 overall, and since December, 1998 with a revised membrane cleaning operation that has boosted production levels.