New method for pre-treating raw materials for fermenting wheat straw biogas

Abstract

The invention discloses a new method for pre-treating raw materials for fermenting wheat straw biogas. The method comprises the following steps of: crushing a wheat straw raw material; adding the crushed wheat straw raw material into a pre-treating reactor; adding a volatile fatty acid or organic waste water which contains the volatile fatty acid into the reactor in the mass ratio of the volatile fatty acid to dry wheat straws being 1:(4-15); adding water into the pre-treating reactor to adjust the mass concentration of the dry wheat straws to 8 to 15 percent; uniformly stirring the mixed materials; and after sealing the pre-treating reactor, pre-treating the materials for 0.5 to 5 hours by heating and soaking the materials, and controlling the temperature of the pre-treatment to be between 80 and 160 DEG C, thus obtaining the pre-treated raw materials. Corrosion to equipment and pipes can be avoided, the loss caused when organics are dissolved is avoided, the accumulation of alkali-metal ions which are introduced in a large amount is reduced, anaerobic fermentation inhabitation and environmental pollution are avoided, the subsequent utilization of biogas residues is facilitated, and the pretreatment cost for unit biogas yield can be reduced.

Description

Technical field: [0001] The invention belongs to the field of renewable energy, and in particular relates to a new method for raw material pretreatment of straw biogas fermentation. Background technique: [0002] China is a large agricultural country, producing about 800 million tons of crop straw every year. Taking 2005 as an example, the national output of rice straw, corn straw and wheat straw was 211 million tons, 202 million tons and 107 million tons respectively, accounting for 25.10%, 24.00% and 12.73% of the total national straw respectively. Of course, the straw mentioned in this article includes a large number of herbaceous energy plants (such as imperial grass, elephant grass, switchgrass, miscanthus, pennisetum) in addition to crop straw (such as rice straw, corn straw, wheat straw, etc.). At present, the energy utilization methods of straw mainly include incineration, gasification, pyrolysis, ethanol fermentation and biogas fermentation. Compared with other co...

AI Technical Summary

Problems solved by technology

However, the currently used acid-base pretreatment methods are mainly strong acid or strong alkali pretreatment, such as hydrochloric acid, sulfuric acid, sodium hydroxide, potassium hydroxide, this pretreatment method generally has the problem of equipment corrosion, and requires a large amount of water for the pretreatment. The processed raw materials need to be cleaned or need a large amount of acid and alkali to neutralize

When washing with water, soluble organic matter will be lost, and when neutralized with acid and alkali, a large amount of sodium ions and chloride ions will be produced, which may not only inhibit anaerobic fermentation, but also cause environmental pollution, and affect the biogas residue Subsequent use

The above problems have seriously affected the application of acid-base pretreatment in large-scale straw biogas projects. Therefore, the development of a new method for straw raw material pretreatment is one of the keys to the promotion of large-scale straw biogas projects.

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