Method for comprehensive utilization of lignocellulosic biomasses

Abstract

The invention discloses a method for the comprehensive utilization of lignocellulosic biomasses, which comprise the following steps: (1) crushing a raw lignocellulose material and adding water so as to form mixed liquid, adding alkaline for adjustment, adding sulfite, and cooking the obtained object so as to obtain a mixture; (2) carrying out solid-liquid separation on the mixture obtained in the step (1), washing and cooling an obtained solid, mixing liquid obtained by washing with liquid obtained by solid-liquid separation, cyclically applying the obtained mixture to the step (1), and when the dry matter content of the liquid reaches a certain value, drying the liquid so as to obtain sulfonated lignin; (3) adjusting the pH value of the solid washed in the step (2), adding cellulase liquid, and carrying out highly enriched material saccharification; (4) adding a yeast into saccharification liquid obtained in the steps (3) to ferment, and treating the fermented mixture so as to obtain anhydrous ethanol; and (5) feeding clostridium beijerinckii into the waste fermentation liquor obtained in the step (4) to ferment, and then distilling the obtained object so as to produce ethanol, acetone and butanol. According to the invention, the efficient utilization of main ingredients such as lignin, cellulose and hemicellulose in lignocellulose biomasses is realized.

Description

technical field [0001] The invention relates to a method for fully utilizing cellulose, hemicellulose and lignin in lignocellulosic biomass, in particular to a method for comprehensive utilization of lignocellulosic biomass. Background technique [0002] With the depletion of fossil fuels, global warming, smog and other environmental problems, the search for clean and renewable energy has become a hot topic. Fuel ethanol has been proven to replace gasoline as a vehicle fuel. The technology of producing ethanol by microbial fermentation is mature. The conversion of lignocellulosic biomass (weeds, forest trees, agricultural waste, etc.) to ethanol has a wide distribution of raw materials and does not compete with humans and animals for food. and other advantages. [0003] Lignocellulosic biomass is mainly composed of cellulose, hemicellulose and lignin. The reducing sugar obtained by hydrolyzing the cellulose and hemicellulose can be used to ferment and produce ethanol, but t...

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Problems solved by technology

[0003] Lignocellulosic biomass is mainly composed of cellulose, hemicellulose and lignin. The reducing sugar obtained by hydrolyzing the cellulose and hemicellulose can be used to ferment and produce ethanol, but the interconnection and complex structure of the three components lead to aggregation. Sugar is not easily hydrolyzed. In order to improve the enzymatic conversion efficiency of cellulose and hemicellulose, it is necessary to remove the lignin in the raw material, retain the cellulose and hemicellulose to the greatest extent, and use it to prepare lignocellulose hydrolyzed sugar, and then through biotransformation Technology conversion to energy products or bio-based chemicals

[0004] Chinese patent CN201110308471 also discloses a comprehensive utilization method of lignocellulosic biomass, which uses N-stage acid hydrolysis of lignocellulosic biomass, wherein the temperature of the first-stage acid hydrolysis is 100-150°C, and each subsequent stage Lower 5-25°C step by step, N is an integer greater than or equal to 2; the slag after acid treatment is enzymatically hydrolyzed, and then the lignin in the enzymolyzed slag is extracted with alkali, and the remaining slag is enzymatically hydrolyzed, and the cycle is repeated. This process is complicated. , and a large amount of acid and alkali is used, which is easy to produce a large amount of waste liquid and cause environmental pollution. The repeated addition of cellulase increases the production cost and is not economical. At the same time, the pentose sugar in this process will decompose after repeated acid treatment to produce fermentation inhibitors , which is not conducive to subsequent use

Chinese patent 201110306624 discloses a method for comprehensive utilization of lignocellulosic biomass. The method is similar to patent CN201110308471, except that one-step phosphoric acid hydrolysis is used. Due to the high price of phosphoric acid, the pentose sugar obtained by pretreatment with phosphoric acid is not high. Value conversion, so this comprehensive utilization method also does not have economic and industrial value

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