| 摘要 |
PROBLEM TO BE SOLVED: To provide a methane fermentation system which efficiently performs methane fermentation by preventing calcium carbonate CaCO(carbonate compound of alkaline earth metal) from being attached to the inside of a tube of a heat exchanger, the calcium carbonate CaCObeing deposited by heating a methane fermentation liquid obtained by subjecting material to be fermented to methane fermentation to a temperature of the methane fermentation liquid or higher and by treating the methane fermentation liquid.SOLUTION: The methane fermentation system comprises: a methane fermentation tank 1 for subjecting the material M to be fermented to methane fermentation (anaerobic treatment); a temperature elevation and maintenance means 2 for elevating or maintaining the temperature in the methane fermentation tank 1; and an alkaline earth metal content reduction treatment part 3 for reducing the content of alkaline earth metal in the methane fermentation liquid output from the methane fermentation tank 1, wherein, in the alkaline earth metal reduction treatment part 3, alkaline earth metals contained in the material M to be fermented are deposited as carbonates of the alkaline earth metals by adjusting the pH and temperature of the methane fermentation liquid, and the content of the alkaline earth metals in the material M to be fermented can be reduced as a result. |
