Method for continuously cooking grass raw materials and equipment used in same

Abstract

The invention provides a method for continuously cooking grass raw materials, comprising the following steps: (1) preparing the grass raw materials before dipping to obtain the prepared grass raw materials before dipping; (2) transferring the prepared fibrous raw materials into an impregnator through a screw feeder, adding impregnation liquid for dipping treatment, putting the prepared grass raw materials in a digester and adding impregnation liquid to the digester at the same time, and then adding hot black liquor for primary cooking to obtain the primarily cooked grass raw materials; and (3) adding cooking liquor to the primarily cooked grass raw materials for secondary cooking to obtain pulp of the grass raw materials. The method of the invention achieves the purpose of continuously cooking the grass raw materials with large liquor ratio, shortens cooking time, reduces energy consumption and improves uniformity of the pulp. The invention further provides cooking equipment used in the method.

Description

technical field [0001] The invention belongs to the field of pulp and papermaking, and more specifically relates to a method for continuous cooking of grass raw materials and equipment used for the method. Background technique [0002] Plant fiber raw materials for papermaking generally include: wood fiber and grass fiber. [0003] Among them, grass fibers have a high content of miscellaneous cells, which are poorly interwoven with fibers, have high lignin content of miscellaneous cells, are not easy to bleach, and have the lowest pulping and papermaking value. The water drainage of straw pulp is poor, the strength of paper is also poor, the value of breaking length is low, the value of tearing degree is low and the number of times of folding endurance is small. Therefore, wood fiber is the most used in papermaking in the world, and grass plant fiber is used less. However, with the shortage of forest resources, how to use grass raw materials to prepare high-quality chemical...

AI Technical Summary

Problems solved by technology

[0015] However, in the prior art, it is impossible to remove the packing tape, larger grass knots and wheat bran from the grass slices obtained after preparing the materials, so the obtained pulp is prone to macula

[0016] This shows that there are following deficiencies in the material preparation method of the above-mentioned prior art: (1) this material preparation method has only separated heavier impurities such as gravel, grain and lighter impurities such as fine dust. Impurities such as grass knots in the cooking agent cannot be removed well during the cooking process, which results in the consumption of the cooking liquid in the subsequent cooking process.

However, the grass knots retain their original shape after being boiled into pulp, and the yellow spots in the pulp are not easy to remove, which affects the quality of the pulp

(2) After dry preparation, the cooking liquid of the grass plant raw material sent to the digester is not easy to penetrate into the interior of the grass raw material, which will cause uneven cooking

[0017] In summary, the prior art does not disclose a method for preparing high-quality grass pulp for papermaking using grass plants as raw materials, and the method of the prior art consumes a lot of cooking energy and causes great harm to the environment. Therefore in order to overcome above-mentioned defective, propose this invention especially

Images