Method for producing hydrogen by fermenting organism and alkali mat composite pretreated straw fiber raw erial at two steps

Abstract

The invention belongs to the technical field of renewable energy sources and particularly relates to a method for producing hydrogen by fermenting an organism and alkali composite pretreated straw fiber raw material at two steps. The method comprises the following steps of: (1) crushing the straw fiber raw material and mixing the crushed raw material with a nutritive salt solution to obtain a mixture; (2) introducing a thermophile bacteria seed solution into the mixture and carrying out the first-step anaerobic fermentation to produce hydrogen gas; (3) mixing fermentation residue, water and sodium hydroxide according to the proportion for alkali pretreatment, pre-treating the residue and washing to be neutral to obtain a compound pretreated straw fiber; and (4) mixing the obtained compound pretreated straw fiber with the nutritive salt solution, introducing the thermophile bacteria seed solution into the mixture and carrying out the second-step anaerobic fermentation to produce hydrogen gas. Compared with the traditional method for producing the hydrogen by pre-treating the straw with alkali, the method for producing hydrogen by fermenting the composite pretreated straw fiber at two steps ensures that the hydrogen-producing level is improved by 75 percent, the utilization rate of the raw material is improved to 70 percent from 40 percent and the expense for the alkali pretreatment is reduced by 40 percent.

Description

technical field [0001] The invention belongs to the technical field of renewable energy. Specifically, the invention relates to a method for producing hydrogen by two-step fermentation of straw fiber raw materials for biological and alkali composite pretreatment. Background technique [0002] In the 21st century, the development of renewable energy has become a hot spot worldwide, and the use of waste biomass for renewable energy has become an important way to deal with energy and environmental crises. Hydrogen can be used directly as a fuel, or it can be directly converted into electrical energy through an electrochemical reaction through a fuel cell for use in transportation, etc. As an energy carrier, hydrogen has outstanding advantages such as high energy density, green and pollution-free, and is a green and renewable energy in the true sense. [0003] According to reports, currently 90% of hydrogen comes from the conversion of primary energy (coal, oil and natural gas)...

AI Technical Summary

Problems solved by technology

However, the traditional alkaline pretreatment process also converts soluble sugars, part of hemicellulose, and cellulose into by-products. On the one hand, the by-products will have a toxic effect on microorganisms, which is not conducive to subsequent fermentation; on the other hand, traditional alkaline pretreatment also reduces Raw material utilization in the fermentation process

[0007] As mentioned above, some methods for producing hydrogen by anaerobic fermentation of straw fiber raw materials have been reported in the prior art, but the requirements for the pretreatment process and cellulase are relatively high, which undoubtedly increases the cost of the hydrogen production process, and the pretreatment process will also reduce It leads to the formation of toxic by-products and the reduction of raw material utilization, while the direct method of high-temperature fermentation of fiber raw materials for hydrogen production has the disadvantage of low hydrogen production efficiency, which greatly hinders the practical application of hydrogen production process