Method for producing ethanol by continuous enzymolysis and fermentation of lignocellulose

Abstract

The invention relates to a method for producing ethanol by continuous enzymolysis and fermentation of lignocelluloses. The method comprises the following steps: (1) a pretreated lignocellulose raw material and an enzyme solution are added in proportion into an enzymolysis reactor with a screw device to carry out continuous enzymolysis; (2) the materials enter a fermentation tank I after enzymolysis, and microzyme is inoculated to carry out simultaneous saccharification and fermentation at 30-38 DEG C; (3) the materials in the fermentation tank I enter a fermentation tank II, and simultaneous saccharification and fermentation are continuously carried out at 39-44 DEG C; (4) the fermented materials undergo reduced pressure distillation; and (5) the distilled materials undergo solid-liquid separation, and an enzyme-containing liquid phase is reused in the step (1). By the use of the screw device, continuous supply and continuous enzymolysis of the raw materials are realized, and enzymolysis efficiency is enhanced. As simultaneous saccharification and fermentation are carried out at different temperatures, enzymolysis efficiency is further improved and yield of ethanol is then raised. The finally-obtained enzyme solution can be directly reused in the enzymolysis process, thus reducing production cost.

Description

technical field [0001] The invention belongs to the field of biomass energy, and in particular relates to a method for producing ethanol by continuous enzymolysis and fermentation of lignocellulose. Background technique [0002] The current economy is overly dependent on fossil fuels such as oil and coal. Their non-renewability is leading to the gradual depletion of resources, and the carbon dioxide produced by combustion has caused the deterioration of the climate and environment. Searching for renewable clean energy has become the focus of researchers. Among them, biomass energy has become the most potential energy source because of its advantages such as wide sources, low price, strong regeneration, and recyclable carbon dioxide. Fuel ethanol is one of the important energy sources derived from renewable biomass. In order to avoid competing with people for food, lignocellulose will become the most potential raw material for fuel ethanol production. [0003] The process o...

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Problems solved by technology

However, the stirring reactor also has the following disadvantages: (1) The enzymatic hydrolysis reaction is carried out at a certain temperature, so the reactor needs to be equipped with a jacket to transfer heat and heat preservation to the material, and the heat transfer efficiency and heat transfer uniformity are limited. Certain problems; (2) The operation process of the reactor enzymatic hydrolysis is periodic and intermittent, that is: feeding→stirring the enzymolysis reaction→discharging. If this process is repeated, there will be troublesome intermittent operations, which will reduce the efficiency of industrial production. (3) The huge body size of the reactor requires that the electromechanical equipment matched with it must have sufficient power and consume a lot of energy, which does not conform to the current concept of green energy saving

The purpose of producing ethanol from lignocellulose-containing raw materials can be achieved by using the above methods, but the enzymatic hydrolysis efficiency is not high, and the ethanol yield is low

[0008] In summary, the method of producing fuel ethanol from lignocellulose has problems such as low enzymatic cellulose efficiency, low enzyme utilization, cumbersome operation, low sugar conversion rate, and low ethanol yield.

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