Production method of chemi-mechanical pulp and semi-chemical pulp

A technology of semi-chemical pulp and production method, which is applied in the field of pulp and paper making, can solve the problems of difficult extraction and utilization of hemicellulose and lignin, difficulty in extracting hemicellulose sugar, and low value, so as to make up for short fibers and reduce Effects of energy consumption and process cost reduction

Active Publication Date: 2020-12-08
QILU UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] From the perspective of the utilization of all components of plant resources, it is difficult to extract and utilize hemicellulose and lignin in conventional mechanical pulp and semichemical pulp waste liquid, because the waste liquid contains a large amount of alkali and sulfur, and the hemicellulose and lignin The extraction of plain sugar is difficult, lignin contains elements such as sodium and sulfur, the purity is poor, and the value is low

Method used

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  • Production method of chemi-mechanical pulp and semi-chemical pulp
  • Production method of chemi-mechanical pulp and semi-chemical pulp

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Effect test

Embodiment 1

[0042] The method for preparing plant material into colored mechanical pulp or semi-chemical pulp of the present invention comprises the following steps.

[0043] a) Material preparation: Wood raw materials are peeled, sliced, and extruded torn, and non-wood raw materials are removed from dust and silt, and cut into short lengths.

[0044] b) Softening: Put the plant material into a macerator, add formic acid / formate, and soak it at a certain temperature for a certain period of time to moisten and soften the plant material.

[0045] In a preferred version, the plant material is coniferous wood, such as masson pine, Korean pine, American black pine wood chips, the purpose is to produce chemical mechanical pulp, the solid-to-liquid ratio is 1:5, the concentration of formic acid is 70wt%, and the ammonium formate consumption is 0.5wt% of the plant material, the reaction temperature is 95°C, and the soaking time is 120min.

[0046] In a preferred version, the plant raw material i...

Embodiment 2

[0065] The bleaching of natural colored mechanical pulp or semi-chemical pulp, specifically, after the pulp is blended in step g), it is bleached. Single-stage bleaching or multi-stage bleaching can be performed.

[0066]In a preferred embodiment, chlorine dioxide is selected as the bleaching agent for single-stage bleaching, and the specific conditions are 12% pulp concentration, 2% chlorine dioxide, 70°C temperature, 2.5h time, and initial pH 4.0 (using sodium hydroxide or Sulfuric acid to adjust pH), under this condition, the brightness of larch softwood pulp reaches 54% ISO, the brightness of poplar hardwood pulp reaches 58% ISO, and the brightness of wheat straw pulp reaches 55% ISO. In a preferred embodiment, the bleaching agent used in multistage bleaching is chlorine dioxide, oxygen and hydrogen peroxide, specifically oxygen delignification (O), chlorine dioxide bleaching (D), hydrogen peroxide bleaching (P), The multi-stage combination of alkali extraction (E), the w...

Embodiment 3

[0068] Recycling technology of chemical-mechanical pulp or semi-chemical pulp waste liquid. The specific scheme of this technology is as follows:

[0069] a) Mix all contained waste liquids, including refining waste liquids and washing waste liquids, and remove fiber suspensions in the mixed liquids through a screen whose mesh number is higher than 80.

[0070] b) evaporating and concentrating the mixed solution, and condensing the steam to obtain condensate and residue. The condensate is an aqueous formic acid solution, and the residue is a mixture of lignin and hemicellulose sugars.

[0071] In a preferred solution, step b) concentrates the mixed solution by evaporation under reduced pressure, the absolute pressure is 80.0kPa, the evaporation temperature is 72°C, and the solid content is controlled between 60-65wt%.

[0072] c) The residue is stirred with water, then put into a filter bag and dehydrated by centrifugation or extrusion to obtain a filtrate and a filter residu...

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Abstract

The invention relates to a method for producing chemi-mechanical pulp or semi-chemical pulp by treating wood or agricultural straw plant raw materials under acidic conditions. The method further comprises the steps of acid recovery and subsequent utilization of hemicellulose and lignin in waste liquid. According to paper pulp production, a formic acid/formate aqueous solution is used for swellingand softening a plant raw material in a mild normal-pressure environment, and lignin and hemicellulose are properly removed. The softened raw materials are hydraulically defiberred and mechanically ground to prepare chemi-mechanical pulp or semi-chemical pulp. In the drying process of the paper pulp and the waste liquid, formic acid recovery and formate co-production are achieved, and the invention further provides a separation method and a subsequent utilization way of lignin and hemicellulose in the waste liquid. Pulping involved in the method is carried out under an acidic condition, and isdifferent from the existing method for producing chemi-mechanical pulp or semi-chemical pulp in an alkaline environment. According to the method, all components of the plant raw materials can be separated and utilized, chemicals are recycled, and good resource utilization benefits and environmental benefits are achieved.

Description

technical field [0001] The present invention relates to a production method of processing plant resources such as wood and agricultural stalks under acidic conditions to produce chemical-mechanical pulp (chemical-mechanical pulp) and semi-chemical pulp, and uses this pulp to make various paper products, which belongs to pulping Paper field. Background technique [0002] The main components of resources such as wood and agricultural straw are cellulose, hemicellulose and lignin. The process of pulping is to obtain pulp that can be speculated into paper through physical and chemical methods. The important functions involved include softening and grinding of raw materials. Fine, chemical delignification and hemicellulose, etc. [0003] According to the production process of pulp, it can be divided into mechanical pulp, chemical mechanical pulp (chemical mechanical pulp), semi-chemical pulp and chemical pulp. These pulps have different properties and different yields. The yiel...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21H11/02D21C1/04D21B1/16D21C9/14D21C9/147C08H7/00C08B37/14C05F11/00C05G5/20C07C51/41C07C53/06
CPCD21H11/02D21C1/04D21B1/16D21C9/144D21C9/147C08H6/00C08B37/0003C05F11/00C05G5/20C07C51/412C07C53/06
Inventor 田国钰邵志勇王兆江秦梦华
Owner QILU UNIV OF TECH
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