Method and device for producing methane by using dry anaerobic digestion for urban sludge and organic matter

Abstract

The invention belongs to the field of reclamation of solid wastes, in particular relating to a method and a device for producing methane by using a dry anaerobic digestion for urban sludge and an organic matter. The device comprises a reaction chamber and a double-layer helix ribbon type agitator and is provided with a feed inlet and outlet, a sample port, a temperature-setting controller, a methane metering device, a stirring control device and others devices. The method comprises the following steps: dewatering sludge is placed into a fermentation tank for inoculation and seal, the revolving speed at start-up stage is 5-15r / min and daily stirring time is 12h, the revolving speed at acid-producing stage is 10-20r / min, intermittent operation is carried out; the daily stirring time is more than or equal to 8h and less than or equal to 16, and starting and stopping frequency for the motor is required to be increased; temperature control is performed at acid-producing stage and methane-producing stage and material temperature is controlled to be 35+ / -1 DEG C; and after finishing the fermentation, one fourth to one third of biogas residues are left for being used as inoculum for the next batch of fermented materials and the rest of residues are discharged. The invention can be applied to reclamation treatment of the urban sludge and can obviously save equipment investment and land occupation compared with the wet fermentation.

Description

Technical field [0001] The invention belongs to the field of solid waste resource recovery, and specifically relates to a method and device for dry anaerobic fermentation of urban sludge and organic matter (such as livestock manure, food waste, etc.) to produce biogas. Background technique [0002] The amount of dewatered sludge produced by the purification of domestic sewage in urban sewage treatment plants is huge, and the current annual collection capacity is about 26 million tons. The sewage treatment plants mostly use concentrated dewatering for landfilling after treatment and disposal. The method not only occupies limited land resources, but also easily causes secondary pollution. In addition, cities produce a large amount of organic waste, such as livestock manure, food waste, etc. The resource utilization rate of these waste landfills is low, which is not in line with the principle of sustainable development in my country. In recent years, the global energy stru...

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Problems solved by technology

[0006] The purpose of the present invention is to overcome the difficulties of mass transfer, difficult enrichment of methane bacteria and difficulty of gas overflow due to the characteristics of high viscosity, no fluidity, and no void ratio in the dry fermentation process of municipal sludge, and overcome other dry fermentation methods. The shortcoming that the equipment cannot achieve efficient microscopic mixing of sludge provides a method and device for producing biogas by dry anaerobic fermentation of municipal sludge and organic matter

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