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Un-bleaching pulp prepared by alkaline steam cooking wheat straw raw material, preparation method and use thereof

A technology of alkaline cooking and unbleached pulp, applied in the field of unbleached pulp, can solve the problems of high carbohydrate content, high viscosity of black liquor, difficult recovery, etc., and achieve the effects of dust reduction, high yield and reduced production cost

Active Publication Date: 2009-06-10
SHANDONG TRALIN PAPER
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

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. Grass fibers contain a large number of miscellaneous cells, which pose a series of hazards to papermaking
However, it has not been reported that high-quality unbleached pulp is prepared by using the ammonium method with rich wheat straw as raw material.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0076] The wheat straw raw material is prepared by the conventional dry method and put into the cooking pot, and the cooking liquid is added into the cooking pot, the amount of alkali used is 11% of the absolute dry raw material in terms of sodium hydroxide, the liquid ratio is 1:4, anthraquinone The amount of addition is 0.5% of the absolute dry raw material. The first heating is raised to 110°C, and the temperature is kept at this temperature for 20 minutes, and the steam is released for 25 minutes. The second heating is raised to 168°C for 90 minutes. The hardness of the high-hardness pulp obtained after cooking is 22, which is equivalent to a kappa value of 35.5. It is diluted with dilute black liquor to a concentration of 2.5-3.5%, and then screened by screening methods in the prior art, such as skip screening. Then use the three-stage vacuum pulp washer in the prior art to wash. After washing, a high-hardness pulp with a concentration of 10% is obtained, and then the pulp...

Embodiment 2

[0078] Put the wheat straw raw material into the cooking pot after conventional preparation by dry method, add the cooking liquid into the cooking pot, the amount of alkali used is 9% of the absolute dry raw material in terms of sodium hydroxide, the liquid ratio is 1:2, anthraquinone The amount of addition is 0.8% of the absolute dry raw material amount. The first heating is raised to 120°C, and the temperature is kept at this temperature for 40 minutes, and then the steam is released for 20 minutes. . Cooking to obtain a hardness of 28 is equivalent to a high-hardness pulp with a kappa value of 50, and then the high-hardness pulp is sent to a twin-roll press for extracting black liquor in the prior art for squeezing. After squeezing, the concentration is 32%. For high-hardness pulp, thicken the juice by 15% with hot water, keep the temperature at 60°C, then heat the pulp to 70°C through a screw conveyor and transport it to the medium-consistency pulp pipe. The pulp is subje...

Embodiment 3

[0080] Put the wheat straw into the cooking pot, add cooking liquid into the cooking pot, the amount of sodium hydroxide added is 11% of the absolute dry raw material, the liquid ratio is 1:3, the amount of anthraquinone added is 0.7% of the absolute dry raw material, Heating up to 130°C for the first time, keeping the temperature for 30 minutes at this temperature, letting off steam for 30 minutes, raising the temperature for 25 minutes to 170°C for the second time, keeping the temperature for 90 minutes. After cooking, a high-hardness pulp with a hardness of 21 equivalent to a kappa value of 33 is obtained, and then washed by a conventional method, and then the concentration of the high-hardness pulp is adjusted to 18%, and then sent to a high-frequency deflaking machine for deflaking. The percussion degree of wheat straw pulp is 20°SR. It can be seen by the naked eye that after the decompressed wheat straw pulp is broken apart, there are no rod-shaped fibers. The percussion ...

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Abstract

The invention discloses unbleached pulp prepared by the alkaline cooking of a wheat straw raw material and a preparation method thereof. The fracture length of the unbleached pulp is between 5.5 and 7.2km, the folding resistance is between 20 and 70 times, the tearability is between 180 and 250 mN, the whiteness is 33 to 42 percent ISO, and the beating degree is between 33 and 38 DEG SR. The unbleached pulp can be taken as pulp of corrugated paper, napkin paper and packing paper. The preparation method comprises the steps of alkaline cooking, oxygen delignification and so on, and the unbleached pulp is obtained by obtaining the hardness which is between 16 and 28 and is equivalent to a Kappa number of between 24 and 50 through the alkaline cooking, and then performing oxygen delignification treatment by introducing oxygen and adding sodium hydroxide, or being matched with a pulp squeezing step and / or a disintegration step before the oxygen delignification. The use of the method can not cause the unbleached pulp to be polluted by a bleaching agent, and the strength of the pulp is protected at the same time, thereby preventing cellulose in the pulp from being degraded due to the influence of bleaching.

Description

technical field [0001] The present invention relates to a kind of unbleached pulp, more specifically, relates to a kind of unbleached pulp prepared from wheat straw raw material, its preparation method and application. Background technique [0002] Wheatgrass is an annual herb with erect stalks and clusters. Wheat straw is one of the grass raw materials with short, small and thin fibers. The average length of the fibers is about 1 mm and the width is 8 μm. There are obvious or inconspicuous pits on the cell wall, and the cell cavity is small. There are many amorphous fine cells in wheat straw, which is a prominent feature of wheat straw. The content of non-fibrous cells in wheat straw is very large, accounting for about 54% of the total cell area, among which the finely broken and incomplete parenchyma cells are the most, which is the main reason for the poor drainage and poor quality of wheat straw pulp. There are more non-fibrous cells in grass blades, grass nodes, and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21H11/12D21H15/02D21C3/02D21C7/00D21C9/00D21C9/18D21D1/20
Inventor 宋明信李洪法陈松涛杨吉慧毕衍金
Owner SHANDONG TRALIN PAPER