Feasibility of utilizing by-product biogas in breweries after being decarbonized for refrigeration chiller and related primary energy efficiency analysis

Abstract

This article analyzes the feasibility of utilizing biogas, by-product of wastewater treatment in breweries, as supplement for cooling during brewing process, considering the favourable condition that the output of beer, biogas, refrigeration load and power consumption are positively correlated. The CO2 and H2S in the biogas can be absorbed either by water physically or by chemical methods. Availability of wastewater in the brewery makes the physical method the first choice. Note that the calorific value of the decarbonised biogas is similar as natural gas, the latter is used instead to simulate primary energy efficiency. Among the three mostly used refrigeration equipment configurations, screw compression chiller driven by motor (CCDM), compression chiller driven by engine (CCDE) and direct-fired absorption chiller (DFAC) are put into comparison as they don’t generate power. Take CCDM as reference, the calculated results shows that DFAC has an obvious advantage, with the highest PEEC that is 126.2%, and the lowest kce consumed per RT that is 0.312. As this article discusses both the use of decarbonised biogas for cooling and the selection of refrigeration equipment configuration, it provides an innovative design for biogas in the renewable energy.