Digester to produce methane from fermenting manure etc. - has riser pipe to recycle and distribute heated liq. manure for faster fermenting

摘要

A digester in which anaerobic fermentation of cellulosic material, e.g. manure, stable litter, can be effected for the prodn. of methane gas. The digester is of the type which is equipped with a heater to improve fermentation rate. Inside the digester vessel a perforated, horizontal bed plate is supported clear of the base so that a space below the bed plate will collect liq. draining from manure on top of the bed plate. Near the top of the vessel space, a perforated head plate fixes the upper level of the batch of manure. A heater is fitted in the drainage space below the bed plate. A riser pipe extends from the drainage space to a discharge point spilling on top of the head plate. The top of the vessel space is closed by a removable cover of which the skirted edge is sealed by an hydraulic joint to the vessel wall. Liq. pref. passes up the river by thermal convection. Alternatively a pump may be employed. Discharge from the upper end of the riser pipe is pref. via an annular syphon. Distribution of warmed, liq. manure throughout the batch of manure on top of the bed plate produces very efficient fermentation. The ratio of methane output to digester vol. is raised and heat input minimised.