Oxygen delignification process for bamboo wood dissolving pulp

A technology of oxygen delignification and dissolving pulp, which is applied in the field of dissolving pulp preparation, can solve the problems of backward production equipment and technology of bamboo dissolving pulp, high consumption of bleaching chemicals, and poor protection of cellulose, so as to save bleaching costs, The effect of high flexibility and stable card price

Active Publication Date: 2012-07-18
CHONGQING LEE & MAN PAPER MFG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, the existing bamboo dissolving pulp production equipment and technology are relatively backward, especially the traditional three-stage bleaching of C-E-H is mainly used in the bleaching process. The wastewater pollution load generated by the bleaching process is large, and there are internationally recognized carcinogens dioxin produce
[0004] There is a one-stage oxygen delignification process in the improved ECF bleaching process, but this oxygen delignification process adopts a one-stage process, which cannot deeply delignify the cellulose, and has poor protection effect on cellulose. The consumption of bleaching chemicals is high, and the load of bleaching wastewater is relatively high. Big

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] An oxygen delignification process for bamboo dissolving pulp, which adopts two-stage oxygen delignification, specifically includes the following process steps:

[0021] A. Add caustic soda accounting for 2.0% of the air-dried pulp weight and 1kg / admt magnesium sulfate to the slurry with a weight concentration of 8% after washing and concentrating in the pulp washer, heat it to 90°C with low-pressure steam, and then send it in by a medium-concentration pump The first medium-concentration mixer, add 20kg / admt oxygen (the pressure of oxygen is 1.0Mpa, the purity of oxygen ≥ 93%) into the first medium-concentration mixer, mix evenly and enter the ascending / downflowing reaction tube, slurry The residence time of the material in the up / down flow reaction tube is 5min;

[0022] B. The slurry coming out of the downflow tower in the first stage is heated to 95°C by medium-pressure steam, and sent to the medium-concentration mixer in the second stage through the medium-concentrat...

Embodiment 2

[0026] An oxygen delignification process for bamboo dissolving pulp, which adopts two-stage oxygen delignification, specifically includes the following process steps:

[0027] A. Add 2.5% caustic soda and 1.5kg / admt magnesium sulfate to the pulp with a weight concentration of 10% after washing and concentration in the pulp washer, heat it to 92°C with low-pressure steam, and then pump it with medium concentration Into the first medium-concentration mixer, add 22kg / admt oxygen (the pressure of oxygen is 1.1Mpa, the purity of oxygen is ≥ 93%) into the first medium-concentration mixer, mix well and then enter the ascending / downflowing reaction tube, The residence time of the slurry in the up / down flow reaction tube is 7min;

[0028] B. The slurry coming out of the first downflow tower is heated to 98°C by medium-pressure steam, then sent to the second-stage medium-concentration mixer through a medium-concentration pump, and 22kg / admt oxygen is added to the second-stage medium-con...

Embodiment 3

[0032] An oxygen delignification process for bamboo dissolving pulp, which adopts two-stage oxygen delignification, specifically includes the following process steps:

[0033] A. Add caustic soda accounting for 2.8% of air-dried pulp weight and 2.5kg / admt magnesium sulfate to the slurry with a weight concentration of 11% after washing and concentrating in the pulp washer, heat it to 93°C with low-pressure steam, and then pump it by medium-concentration Into the first medium-concentration mixer, add 24kg / admt oxygen (the pressure of oxygen is 1.1Mpa, and the purity of oxygen is ≥ 93%) into the first medium-concentration mixer, mix well and then enter the ascending / falling flow reaction tube, The residence time of the slurry in the up / down flow reaction tube is 8min;

[0034] B. The slurry from the first downflow tower is heated to 100°C by medium-pressure steam, then sent to the second-stage medium-concentration mixer through a medium-concentration pump, and 24kg / admt oxygen is...

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Abstract

The invention belongs to the technical field of preparation of dissolving pulp, and particularly relates to an oxygen delignification process for bamboo wood dissolving pulp. In the process, two sections of oxygen delignification are adopted, and the process comprises the following steps of: A, adding caustic soda in an amount which is 2.0 to 3.0 percent based on the weight of air dry pulp and 1 to 3 kg / admt magnesium sulfate into concentrated pulp, heating to the temperature of 90 to 95 DEG C, feeding into a first-section medium consistency mixer, adding oxygen, mixing, allowing the pulp to enter an up / down flow reaction pipe, and remaining the pulp in the up / down flow reaction pipe for 5 to 10 minutes; and B, heating the pulp flowing from a first-section down flow tower to the temperature of 95 to 102 DEG C, feeding into a second-section medium consistency mixer, adding oxygen, mixing uniformly, feeding into an up flow tower, remaining for 60 to 80 minutes, and after the pressure of the top of the up flow tower reaches 300 to 600 kPa, and spraying to an oxygen delignification spraying groove. After two sections of oxygen delignification, the lignin content of the pulp is lower, and the using amount of chemicals required by subsequent bleaching is reduced further.

Description

technical field [0001] The invention belongs to the technical field of preparation of dissolving pulp, in particular to an oxygen delignification process of bamboo dissolving pulp. Background technique [0002] Dissolving pulp is widely used in textile viscose fiber, nitrocellulose, cellulose acetate and other cellulose derivative industries, and the market demand is gradually expanding. At present, the newly developed bamboo dissolving pulp has a broad market prospect and can fill the gap of dissolving pulp in my country. [0003] However, the existing bamboo dissolving pulp production equipment and technology are relatively backward, especially the traditional three-stage bleaching of C-E-H is mainly used in the bleaching process. The wastewater pollution load generated by the bleaching process is large, and there are internationally recognized carcinogens dioxin produce. [0004] There is a one-stage oxygen delignification process in the improved ECF bleaching process, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D21C9/147
Inventor 李文俊
Owner CHONGQING LEE & MAN PAPER MFG
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