Comprehensive straw utilization method

Abstract

The invention relates to a comprehensive straw utilization method, which belongs to the technical field of comprehensive biomass material utilization. The method mainly comprises the following key steps: straw cutting, dry dedusting, hot-water washing for sand removal, continuous cooking, discharge and reception, multi-stage countercurrent washing, multi-stage high-concentration pulping, fiber grading, long fiber concentration, long fiber curing, long fiber pulping, production of corrugated paper from long fibers, short fiber concentration, production of fuel ethanol and solid pellet fuel by enzymolysis, fermentation and distillation of short fibers and the like. The method has the advantages that the high-value comprehensive utilization of each component of straw material is realized, chemicals are not added, a water system is closed and circulated, and no wastewater is discharged; the tiny fiber component has a large specific surface area and high enzymolysis efficiency; the corrugated paper produced from the long fiber component has high strength and good quality; and applying the tiny fiber component to an enzymolysis system not only increases the enzymolysis of the material, but also greatly reduces the cost of saccharide enzymolysis, thus promoting the development of the comprehensive biomass utilization technology.

Description

technical field [0001] The invention belongs to the technical field of comprehensive utilization of biomass raw materials, in particular to a method for comprehensive utilization of straw. Background technique [0002] There is a shortage of wood resources in my country. Not only is there a shortage of coniferous wood, but the limited fast-growing broad-leaved wood is also mainly due to construction and furniture panels. Although large enterprises also have artificial forest land, they mainly produce bleached pulp. [0003] In 2017, my country's total output of corrugated boxboard and other industrial packaging paper was 47.2 million tons, accounting for 42% of China's total paper output of 111.3 million tons; my country is the world's largest importer of waste paper, with 25.72 million tons of waste paper imported in 2017; Due to repeated recycling and reuse of domestic waste paper, the fiber strength and yield decrease, and the fiber quality becomes worse and worse, resulti...

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Problems solved by technology

[0003] In 2017, my country's total output of corrugated boxboard and other industrial packaging paper was 47.2 million tons, accounting for 42% of China's total paper output of 111.3 million tons; my country is the world's largest importer of waste paper, with 25.72 million tons of waste paper imported in 2017; Due to repeated recycling and reuse of domestic waste paper, the fiber strength and yield decrease, and the fiber quality becomes worse and worse, resulting in an increase in the amount of chemical additives and an increase in sewage treatment costs; only imported OCC (waste containerboard) To increase the addition of fresh fiber to improve fiber strength and yield

[0011] As raw material of plant straw, pulp used for producing corrugated paper, if chemicals such as sodium hydroxide are added, most of the 1% sodium hydroxide extract component will enter the cooking liquor, and a large part of the higher ash content is mainly silicate Inorganic substances also enter the cooking liquid, so that the cooking liquid not only has a high content of dissolved substances, but also has high viscosity, poor drainage, and increased washing water, resulting in low concentration and large amount of wastewater. Due to the poor biodegradability of alkaline degradation products, General BOD 5 / COD does not exceed 0.35, which belongs to refractory wastewater, and the investment and operation costs of wastewater treatment facilities are extremely high, and it is difficult to meet the standard

[0012] In addition, steam blasting is used to process straw materials, and then they are used as corrugated pulp ingredients after refining. Since the blasting effect has no direction selectivity, a large number of fibers are radially broken, and a large number of fiber fragments are produced. Strictly speaking, the material produced by this method cannot be regarded as pulp, does not have the technical characteristics required by pulp, and cannot be used alone to produce paper, but is only used as an ingredient, or in waste paper pulp Incorporate or mix in chemical pulp to produce paper products; the products to be mixed include corrugated paper or fiber pressed products such as lunch boxes and dinner plates; there is another method, which is to cut and impregnate straw raw materials, and directly use high-consistency mill Pulping machine or twin-screw pulping machine combined with high-consistency refiner for refining, the quality of this product is the same as the above-mentioned method, and the use and function are basically the same; the prepared "pulp" does not have the technical characteristics of pulp, it is If paper products such as corrugated paper cannot be produced, they can only be used as ingredients

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