Search

CN-121976408-A - Method for pretreatment of lignocellulose in time-wide temperature range-low concentration

CN121976408ACN 121976408 ACN121976408 ACN 121976408ACN-121976408-A

Abstract

The invention discloses a method for pretreating lignocellulose at a time-wide temperature range and low concentration, which is characterized in that lignocellulose reacts with a mixed solution containing sodium hydroxide, urea and hydrogen peroxide to obtain cellulose residues. Compared with the traditional high-temperature pretreatment, the method can effectively destroy the lignin structure in the cellulose residue under the conditions of low temperature, room temperature and medium temperature by adopting the high-solid-phase pretreatment technology of sodium hydroxide-urea-hydrogen peroxide, and can realize the high-efficiency separation of cellulose, hemicellulose and lignin by filter pressing and the like while degrading lignin, so that each component is fully utilized. The invention adopts filter pressing dehydration to replace the traditional water washing, greatly reduces water consumption, reduces wastewater discharge, and converts byproduct waste liquid into methane through anaerobic digestion, thereby forming a virtuous circle of waste recycling-clean energy and achieving zero waste discharge.

Inventors

  • ZHU CHENJIE
  • CHEN JINMENG
  • CHEN YANJUN
  • WANG SHILEI
  • Cai Yafan
  • WANG ZHI
  • JI LEI

Assignees

  • 南京工业大学

Dates

Publication Date
20260505
Application Date
20260226

Claims (10)

  1. 1. A method for pretreating lignocellulose, characterized in that lignocellulose is reacted with a mixed solution containing sodium hydroxide, urea and hydrogen peroxide to obtain cellulose residues; Wherein, the In the mixed solution, the mass concentration of sodium hydroxide is 1% -3%, the mass concentration of urea is 1% -2%, and the mass concentration of hydrogen peroxide is 0.1% -0.5%.
  2. 2. The method of claim 1, wherein the lignocellulose comprises wood fibers and residues thereof, optionally the lignocellulose comprises any one or a combination of corn stover, wheat straw, rice straw, soybean straw, sugar cane straw, sorghum, peanut straw, sweet potato straw, hardwood, cork, sweet sorghum, water hyacinth, algae, and coconut shells, the residues comprise cellulose residues, optionally corn stover residues, bagasse, and olive residues, and the cork comprises willow.
  3. 3. The method of claim 1, wherein the lignocellulose has a solids loading in the mixed solution of 0.2-0.4 g/mL.
  4. 4. The method of claim 1, wherein the reaction time is 8 to 20 hours.
  5. 5. The method of claim 1, wherein the temperature of the reaction is 25-80 ℃.
  6. 6. The method as recited in claim 1, further comprising: the obtained cellulose residues are subjected to filter pressing to obtain filter pressing materials and filter pressing waste liquid; performing enzymolysis on the obtained filter-pressed material, and separating to obtain enzymolysis supernatant and enzymolysis residues; taking the obtained enzymolysis supernatant as a fermentation medium, inoculating a yeast strain for fermentation to produce ethanol, and separating to obtain ethanol and fermentation waste liquid; and carrying out anaerobic fermentation on any one or more materials of the obtained filter-pressing waste liquid, enzymolysis residues and fermentation waste liquid and sludge to produce methane.
  7. 7. The method according to claim 6, wherein the total mass of solid matters in the filter-pressed material is 55% -65%.
  8. 8. The method according to claim 6, wherein the solid content in the enzymatic hydrolysis reaction system is 0.2-0.5 g/mL.
  9. 9. The method of claim 6, wherein the mass ratio of dry matter of the material to sludge in the anaerobic fermentation is 1:2-5.
  10. 10. The process according to claim 6, wherein the anaerobic fermentation is carried out at a temperature of 30-40 ℃.

Description

Method for pretreatment of lignocellulose in time-wide temperature range-low concentration Technical Field The invention relates to the field of biomass resource utilization, in particular to a method for pretreatment of cellulose residues in a time-wide temperature range and low concentration, ethanol production by fermentation and methane production by anaerobic digestion of process wastes. Background With the increasing shortage of fossil fuel resources and the approaching worldwide carbon neutralization targets for climate change, the development of renewable, low-carbon alternative energy has become an urgent need in the global energy field. Among many alternative energy sources, fuel ethanol is an important path for reducing fossil energy use and realizing green energy transformation due to its renewable and environment-friendly properties. The cellulose slag is a byproduct generated in the processes of biomass processing, paper industry, food fermentation and the like, has stable source and high cellulose content, and is a potential high-quality raw material for producing fuel ethanol. However, the cellulose residues generally still retain higher crystallinity and partial lignin residues, have compact structure and strong enzymolysis resistance, so that the conversion efficiency is lower, and become a main technical bottleneck for recycling the cellulose residues. At present, the main stream pretreatment method for cellulose slag mostly depends on a strong acid or strong alkali system, and although structural wall breaking can be realized, the problems of harsh process conditions, large dosage of medicaments, high energy consumption and high cost generally exist. Meanwhile, the chemical pretreatment process can generate a large amount of waste liquid with high salt or high organic load and solid residues which are difficult to dispose, and if the recycling treatment is not performed, additional pressure is brought to the environment. In addition, fermentation inhibitors such as furfural, phenols and the like are easy to generate by strong acid and alkali pretreatment, an additional detoxification step is needed, the process complexity is further increased, and the subsequent fermentation efficiency and the ethanol yield are obviously reduced. Therefore, developing a rapid pretreatment technology suitable for the mild, efficient and low-medicament requirements of cellulose residues, reducing inhibitor generation and realizing the resource utilization of subsequent wastes is a key requirement for pushing the cellulose residues to convert into fuel ethanol. Disclosure of Invention The invention aims to solve the technical problems of the prior art and provide a method for pretreating lignocellulose in a time-wide temperature range and low concentration, which realizes the efficient conversion of cellulose residues into ethanol through an enzymolysis fermentation process, utilizes waste anaerobic digestion in the process to produce methane, and realizes the efficient utilization of all components and zero waste emission. In order to solve the technical problems, the invention discloses the following technical scheme: a method of pre-treating lignocellulose comprising the steps of: (1) Reacting lignocellulose with a mixed solution containing sodium hydroxide, urea and hydrogen peroxide to obtain cellulose residues; (2) The obtained cellulose residues are subjected to filter pressing to obtain filter pressing materials and filter pressing waste liquid; (3) The obtained filter-pressed material is subjected to enzymolysis under the action of cellulase, and is separated to obtain enzymolysis supernatant and enzymolysis residues; (4) Taking the obtained enzymolysis supernatant as a fermentation medium, inoculating a yeast strain for fermentation to produce ethanol, and separating to obtain ethanol and fermentation waste liquid; (5) And carrying out anaerobic fermentation on any one or more materials of the obtained filter-pressing waste liquid, enzymolysis residues and fermentation waste liquid and sludge at medium temperature to produce methane. In step (1), the lignocellulose comprises lignocellulose and residues thereof, in some embodiments, the lignocellulose comprises any one or a combination of corn stalk, wheat stalk, straw, soybean stalk, sugarcane stalk, sorghum, peanut stalk, sweet potato stalk, hardwood, cork, sweet sorghum, water hyacinth, algae and coconut shell, the residues comprise cellulose residues, optionally corn stalk residues, bagasse and olive residues, and the cork comprises willow. In some embodiments, the lignocellulose is oven dried and crushed. In some embodiments, the lignocellulose is pulverized to 20-60 mesh, such as 40 mesh. In the step (1), the concentration of each component in the mixed solution is lower, a sodium hydroxide-urea-oxygen synergistic compound auxiliary agent system is formed, and the solvent is water, wherein the mass concentration of sodium hydroxide is 1% -4%,