Scouring process for grass pulping course

A technology of pulping process and process, which is applied in the field of washing process, and can solve the problems of low viscosity, poor water filtration performance, and poor cleaning degree, etc.

Active Publication Date: 2007-12-05
SHANDONG FUYIN PAPER & ENVIRONMENTAL PROTECTION TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] It is generally believed that different types of pulp have different degrees of difficulty in washing. Generally, long fibers have good water filtration performance and are easy to wash. Grass pulp contains more miscellaneous cells and has a lot of semi-fiber content, so it is easy to hydrate. Compared with wood pulp, the water filtration performance is poor, and it is more difficult to wash. At the same time, wood pulp made by alkaline method is more difficult to wash than wood pulp made by acid method.
[0005] For straw pulp, the pulp has high hardness and low viscosity, and the water filtration performance is good at the beginning, but the washing degree is poor at the end. The waste liquid mainly diffuses outward from the cell lumen through the paper pores. The pulp with high hardness has the highest diffusion resistance of the waste liquid in the fiber, and the more difficult it is to wash

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] The rice straw is cooked by the ammonium method. After cooking, the hardness of the rice straw pulp is 16 potassium permanganate, which is equivalent to a Kappa value of 24. The concentration of the straw pulp is adjusted to 10% with black liquor, and then pumped to the screw press. Carry out "thick" black liquor treatment, the obtained thick black liquor can be used for subsequent evaporation as fertilizer, the concentration of the extruded pulp is increased from 10% before squeezing to 18%, and the pH value of the pulp at this time is 8 , the concentration of the extruded black liquor is 9°Be' (20°C), the residual ammonium is 8g / L, and the straw pulp obtained after pulping is used to dilute the pulp to a concentration of 2.5-3.0%, and then sent to the sieve for skipping Coarse pulp is screened, the loss of skipping screen is 0.3%, and the straw pulp obtained after skipping screen is washed by drum type vacuum pulp washer. 36 ° SR, washing first with a concentration of...

Embodiment 2

[0034]The wheat straw is cooked by the ammonium method, and the hardness of the wheat straw pulp obtained after cooking is 18. The potassium permanganate value is equivalent to the kappa value of 29. When the wheat straw pulp has just finished cooking, when the temperature is 160 ° C, the concentration is adjusted to 10%, the wheat straw pulp is pumped to the screw press for squeezing, and the extruded black liquor is evaporated as fertilizer, and the concentration of the extruded pulp is increased from 8% before squeezing to 19%. The PH value is 8, the concentration of the extruded black liquor is 11°Be' (20°C), the residual ammonium is 8g / L, and then the obtained wheat straw pulp is diluted with black liquor to a pulp concentration of 2.5-3.0%. Sent to the skipping screen for coarse pulp screening, the skipping screen loss is 0.2%, and then the wheat straw pulp obtained after the skipping screen is washed with a horizontal belt vacuum pulp washer, the temperature during the w...

Embodiment 3

[0036] The rice straw is cooked by alkaline method, and the hardness of the cotton straw pulp obtained after cooking is 20, and the potassium permanganate value is equivalent to a kappa value of 34. The concentration of the pulp is increased from 8% before squeezing to 20%. At this time, the pH value of the pulp is 8.5. The obtained pulp is added to the black liquor for jumping screen. Before the jumping screen, adjust the concentration of the pulp and dilute the concentration of the pulp to 3.0 %, the loss of sieve skipping is 0.2%, and then the pulp obtained after sieving skipping is transported to the deflagging machine for deflaking, and at the same time, alkali with a concentration of 38g / L is added to the deflaking equipment, and the weight of the lye is 3% of the dry pulp quality. %, the percussion degree of the straw pulp before deflaking is 20°SR. It can be seen by the naked eye that after the straw pulp has been decompressed, there are no rod-shaped fibers. This shows...

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PUM

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Abstract

The invention provides a washing process in the grass pulping. It contains the following steps: A) send the cooked pulp into the presser for pressing to get the coarse pulp. B) Process the coarse pulp through the jumping screen. C) Send the screened pulp into the pulp washer for washing. The rigidity of the screened pulp is potassium permanganate value 16-28 (equals to karber value 24-50). The washed solvent remains 90-150ppm. Take the high rigidity pulp in this invention as materials to prepare bleaching chemical pulp by pressing and washing. The whiteness of the chemical pulp is 68-82%ISO and the removal rate of the lignin is 84-98%. The quality of the bleaching chemical pulp prepared by the grass is similar, even better than that of the exciting hardwood pulp.

Description

technical field [0001] The invention relates to a washing process in the grass pulping process. Background technique [0002] Grass raw materials have fine fibers, many miscellaneous cells, high ash and five-carbon sugar content, and the black liquor obtained by alkaline pulping and cooking has a high viscosity. Therefore, when the alkaline-cooked grass raw material is washed in a vacuum washing machine, it is easy to form a tight filter layer, the filtration resistance is large, and the washing efficiency is worse than that of wood pulp. [0003] In the May 2006 volume 25 of "Pulping and Papermaking" magazine, the article titled "Talk about the combination process of drum vacuum pulp washer and twin-screw press from black liquor extraction calculation" is mentioned in the article. In order to achieve a high extraction rate of black liquor in the washing process, some manufacturers install a double-screw squeezer in front of the washing machine to directly extract the thick...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21C9/02
Inventor 李洪法陈松涛宋明信杨吉慧宋建军
Owner SHANDONG FUYIN PAPER & ENVIRONMENTAL PROTECTION TECH
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