Methane fermentation gas purification system and methane fermentation gas purification method

摘要

PROBLEM TO BE SOLVED: To improve efficiency of the entire system by that methane gas obtained from organic waste is all recycled.SOLUTION: In this methane fermentation gas purification system 1, a boiler 8 heats water by using methane gas as fuel included in exhaust gas supplied through bypass flow channels 13a-13c, and a digestion tank 2 is warmed-up by hot water and vapor. As a result, because a small amount of methane gas included in gas exhausted by a methane fermentation gas purification process is used for warming-up the digestion tank 2, efficiency of the entire system can be improved by all recycling methane gas obtained from organic waste. Moreover, because a control device 9 controls a feed rate of methane fermentation gas to a gas purification part 7 to obtain calorie necessary for warming-up the digestion tank 2 based on calorie necessary for warming-up the digestion tank 2 and the concentration of methane gas included in exhaust gas, the digestion tank 2 can be always controlled in an optimal operating condition.