METHOD AND SYSTEM FOR METHANE FERMENTATION PROCESSING OF SLUDGE USING HYDROTHERMAL REACTIONS

摘要

Provided are a methane fermentation processing method and system capable of increasing the amount of methane gas recovered from sludge which has been previously processed by hydrothermal reactions. After sludge (S) has been concentrated to a prescribed moisture content by means of a concentration device (4), the concentrated sludge (S) is circulated for a prescribed amount of time between a hydrothermal reactor (11) and a gas-liquid separator (12) to reduce the molecular weight of the sludge while the same is heated to a hydrothermal temperature (T) so as to maximize the amount of methane gas recovered per unit amount of sludge resulting from methane fermentation processing. The low molecular weight sludge (S) is retained for a prescribed amount of time in a methane fermentation tank (20), and the methane gas (G) is recovered. Ideally, the hydrothermal temperature (T) is a temperature in the range 160-200°C which maximizes the amount of methane gas recovered per unit amount of sludge resulting from the methane fermentation processing, the low molecular weight sludge (S) is retained for 3-5 days in the methane fermentation tank (20), and the methane gas (G) recovered.