A chemical mechanical pulping process

Abstract

The invention discloses a chemi-mechanical pulp manufacturing technology which includes the step of wood chip washing, the step of extruding and dipping, the step of pulp grinding, bleaching and pulp washing, the step of screening, purifying and regrinding of pulp residues, the step of pulp condensation and storage, the step of water circulating use and the step of chemical application and control. In the step of extruding and dipping, the extruding and dipping technology and an extruding and tearing device are used, heated and softened wood chips are evenly squashed in the texture direction, air in the wood chips and extracts affecting bleaching are discharged, it is ensured that the wood chips evenly absorb bleaching chemical liquid to be in a saturated state, fibers are promoted to be in the best moist and expanded state, and accordingly separation of the wood chips and fibrillation of the fibers are facilitated. The chemi-mechanical pulp manufacturing technology is wide in raw material application range and successfully combines the advantages that chemical pulp is high in strength and mechanical pulp is high in yield, produced bleached pulp can be used for newsprint, high-grade toilet paper, facial tissues, high-grade culture and printing paper, coating paper, light paper, white paper boards, food package paper and the like, and development prospects are wide.

Description

technical field [0001] The invention relates to a high-yield pulping process of lignocellulosic raw materials, in particular to a method for dissociating fibers by combining chemical and mechanical methods, and using environmentally friendly bleaching chemicals to complete the bleaching task during the fiber dissociation process, which can produce different The invention relates to an energy-saving and environment-friendly chemical-mechanical pulping process for whiteness pulp, which belongs to the technical field of papermaking. Background technique [0002] At present, resources, energy consumption and environmental protection are several major issues facing the world's paper industry. Green and low-carbon production technology and equipment have become an important topic of great concern and research in the paper industry. [0003] 1. Modern chemical pulp mills have the basic characteristics of technology-intensive, capital-intensive, energy-intensive and large-scale, but...

AI Technical Summary

Problems solved by technology

Compared with the two, BCTMP adopts the fine pulp bleaching process after sieving, which has high bleaching efficiency and a wide range of pulp types, but has defects such as complicated process, large investment, high power consumption and difficult treatment of sulfide-containing wastewater; PRC -Although APMP summarizes the advantages of the pulping process and equipment of APMP and BCTMP, there are still defects in the pretreatment of raw materials, refining combination, bleaching combination and pulp washing, etc., resulting in unsatisfactory power consumption and raw material consumption. The bleaching efficiency is relatively low, and it is suitable for pulp with a brightness not higher than 80% ISO. It is difficult to achieve high brightness pulp, and the cost and investment are high.

[0005] 3. Other chemical-mechanical pulping processes developed in China, such as extrusion mechanical pulp (EMP) and alkaline hydrogen peroxide twin-screw chemical-mechanical pulp (APSP), although the power consumption is low, the quality of the pulp is poor, which is suitable for production capacity The small scale and high system operating costs cannot meet the basic requirements and development trends of large-scale energy conservation and environmental protection in the modern paper industry.

[0006] 4. The scale of chemical-mechanical pulp is gradually expanding, and the number of purchased commercial wood chips is gradually increasing, and the types of wood are relatively mixed. The conventional chemical-mechanical pulping process can no longer perform well on wood chip removal and purification, water leveling, extrusion impregnation, and pulping and bleaching. Adapt to production needs

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