Method for extruding black liquor from high-hardness plasm obtained by boiling grass plant raw material

Abstract

The invention provides a method to remove black liquor by a presser from the high rigidity pulp prepared by cooling the grass materials. Send the cooked pulp which has the rigidity of potassium permanganate value 16-28 (equals to karber value 24-50) into the inlet of the presser for pressing. The pulp discharges from the outlet after removing the black liquor. The invention aims at pressing the low concentration and high rigidity pulp prepared by cooling the grass materials to remove the black liquor. It prepares for the necessary washing and bleaching steps during the processing, advances the bleaching effect and saves the necessary chemicals for bleaching, which is an economic and environmental protection method.

Description

technical field [0001] The invention relates to a process for preparing bleached chemical pulp, more specifically, to a method for extruding black liquor from high-hardness pulp obtained after cooking in the process of preparing bleached chemical pulp with grass plant fibers as raw materials. Background technique [0002] The methods of producing pulp from plant fibers are: chemical method, mechanical method and chemical mechanical method. Chemical pulping is the most widely used pulping method by removing certain components in the plant fiber raw material to dissociate the raw material into pulp by means of chemical action. [0003] The chemical pulping in the prior art uses plant fiber as raw material. The process is to prepare the raw materials first, put the pretreated raw materials for pulp production into steaming balls or vertical pots (cooking pots, vertical cooking pots, continuous digesters) and other equipment, and then add sodium hydroxide or sulfurous acid Che...

AI Technical Summary

Problems solved by technology

[0006] 3. Due to the high content of silicon and carbohydrates in the raw materials, the viscosity of the black liquor is high and the recovery is difficult

4. Grasses now contain a large number of miscellaneous cells, which pose a series of hazards to papermaking

The patent provides a method for mechanically preparing pulp, which is used to produce various papers, and the quality of the products is not high

[0010] Due to the small fiber, many miscellaneous cells, and high content of ash and five-carbon sugars in the grass raw material, the pulping and cooking temperature of the grass raw material in the prior art is relatively high, and the cooking and heat preservation time is relatively long, which consumes a lot of energy. , the hardness of the pulp obtained by cooking is low, so the viscosity of the obtained black liquor is also high, which is not conducive to the separation of black liquor and pulp