Comprehensive utilization method of biomass raw material

Abstract

The invention relates to a comprehensive utilization method of a biomass raw material, and concretely relates to a method for preparing a paper pulp by utilizing the biomass raw material, recovering lignin and realizing the combined production furfural and biochar. The method is characterized in that the biomass raw material is boiled through a formic acid and acetic acid mixed organic acid under the catalysis action of hydrogen peroxide; and in the paper pulp preparation process, lignin in the black liquor is recovered, and the combined production of furfural and biochar is realized by utilizing a residual pentose solution. The whole technology has a simple route by designing reasonable technological parameters, is suitable for wood raw materials, and is also suitable for grass raw materials; a subsequent bleaching technology of the process route is simple, and the drainability of the obtained paper pulp is good; the boiling process is carried out in a closed reaction container, and a certain pressure exits in the container because of partial evaporation of formic acid, acetic acid and hydrogen peroxide, so the raw material boiling time is shortened, and the destroys to celluloses are reduced.

Description

technical field [0001] The invention relates to a method for comprehensive utilization of biomass raw materials, in particular to a method for preparing pulp by using biomass raw materials and recovering lignin and xylose. Background technique [0002] Biomass raw materials exist in the form of plants, and the main components are cellulose, hemicellulose and lignin, of which cellulose accounts for about 40%, hemicellulose accounts for about 25%, and lignin accounts for about 20%. The total amount of biomass raw materials generated by photosynthesis exceeds 200 billion tons, so biomass raw materials are the most abundant and cheapest renewable resources on the earth. [0003] Cellulose is the main component of plant cell walls. The cellulose used for textile and papermaking in the world reaches 8 million tons per year. Cellulose is the main component of pulp, and there are also substances such as hemicellulose, lignin, resin, pigment, pectin and ash to varying degrees. Amo...

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Problems solved by technology

But this patent also has the following disadvantages: 1. From the description in the manual, it can be seen that the process uses organic acid mixed with a catalyst represented by sulfuric acid for the first step of catalysis, and sulfuric acid needs to be added for catalysis during the reaction process, which is unavoidable 2. This process uses organic acid and a catalyst represented by sulfuric acid to cook biomass together. In the step of distilling organic acid, if the distillation of organic acid is not complete, the lignin cannot be completely precipitated , if the organic acid is completely distilled out, the concentration of sulfuric acid added to it will increase, which will carbonize the lignin and affect the extraction rate of lignin; 3. Although the same organic acid is used in the extraction and washing of cellulose in the whole process , and the collected pretreatment liquid and washing liquid are directly used for recycling to the reaction kettle of the first step, but a large amount of dissolved lignin and pentose sugar solution also accumulate in the whole mixed liquid, in view of the saturation degree of organic acid extraction However, the effectiveness of the mixed black liquor to extract lignin will be greatly reduced. Therefore, although this step is a circular reaction, it has little effect on the overall extraction efficiency; 4. In the collected pretreatment liquid and washing liquid, due to the dissolved The pentose sugar produced by cooking a large amount of hemicellulose, and the pentose sugar will continue to contact with the organic acid during the multiple circulation of the mixed liquid, and the esterification reaction will occur to form esters. This patent is based on the comprehensive utilization of biomass raw materials. Therefore, it does not care whether the whole process can obtain pentose sugar alone, but for the process of obtaining pentose sugar for the purpose of separation, this process is not applicable; 5. The black liquor obtained by mixing needs to be circulated more than 3 times and then Carrying out evaporation treatment to separate the organic acid, and diluting the obtained concentrated solution to precipitate lignin will cause a huge amount of black liquor and concentrated solution to be processed at one time, which not only affects the treatment efficiency but also makes it difficult to achieve the continuity of the process;6 , It can be seen from the instructions that the extraction rate of cellulose in this process is only 38-55%, and the extraction rate of lignin is 6-16%, and the extraction rate of the whole process is relatively low

Although the patent separates cellulose, hemicellulose and lignin in one process line, the design of the process is to extract cellulose as the ultimate goal, and the design of the whole process does not consider the loss of lignin and pentose sugars , in the step of adding water to extract the precipitate in the step of separating lignin, it will be difficult to remove all lignin due to the large amount of formic acid and acetic acid in the solution, even if a large amount of water is added, the complete precipitation of lignin cannot be guaranteed because formic acid and acetic acid are dissolved in it , resulting in loss of lignin. Obviously, this process only focuses on the process of extracting cellulose to the maximum extent, and has no guiding significance for the efficient extraction of lignin and xylose

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