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Pulp-bleaching technique

A process and pulp technology, applied in the field of pulp bleaching process, can solve the problems of large pulp viscosity loss, heavy waste water load, excessive waste water AOX, etc.

Inactive Publication Date: 2010-06-30
WUHAN CHENMING HANYANG PAPER
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Traditional non-wood fiber pulp and hardwood fiber pulp are mainly produced by the CEH three-stage bleaching process, but the CEH three-stage bleaching process has low bleaching brightness and yield, large pulp viscosity loss, heavy wastewater load, and wastewater AOX seriously exceeds the standard Shortcomings

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment example 1

[0029] With bleaching process bleaching reed pulp of the present invention, concrete process condition is as follows:

[0030] 1. The first stage: Oxygen delignification stage: pulp concentration 13wt%, temperature 95°C, oxygen (100%) dosage 15.8kg / t pulp, NaOH dosage 3kg / t pulp, magnesium sulfate dosage 0.3wt of the pulp %, wash off the residue with water.

[0031] 2, the second stage; the concentration of reed pulp after washing is 11wt%, firstly add NaOH to adjust the pH value to 11, then add H 2 o 2 13kg / t slurry, the slurry temperature is 55°C (no heating required), enter the reaction tower through a double-roller mixer, treat for 60min, and then wash with water to remove the reaction residue, and the whiteness of the slurry reaches 70%.

[0032] 3. The third paragraph: use calcium hypochlorite to supplement bleaching,

[0033] Slurry concentration 10wt%

[0034] Drift rate 1.5%

[0035] Temperature 40°C

[0036] Time 80min

[0037] The reaction residue is washed a...

Embodiment example 2

[0042] With bleaching process bleaching poplar pulp of the present invention, concrete process condition is as follows;

[0043] 1. The first stage: Oxygen delignification stage: pulp concentration 15%, temperature 120°C, oxygen (100%) dosage 18kg / t pulp, NaOH dosage 3.6kg / t pulp, magnesium sulfate dosage 0.45%, wash off with water The residue.

[0044] 2. The second stage; the concentration of poplar pulp after washing is 11.2%, adjust the pH value to 11, add H 2 o 2 16kg / t slurry, the slurry temperature is 62°C, enters the reaction tower through a double-roller mixer, is treated for 90 minutes, and then washed with water to remove the reaction residue, and the whiteness of the slurry reaches 74%.

[0045] 3. The third paragraph: use calcium hypochlorite to supplement bleaching,

[0046] Slurry concentration 10.5%

[0047] Drift rate 2.5%

[0048] Temperature 42°C

[0049] Time 100min

[0050] The reaction residue was washed away with water, and the whiteness of the pu...

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Abstract

The invention relates to a pulp-bleaching technique. 40 percent to 50 percent by weight of residual lignin of boiled pulp is removed by way of oxygen delignification, hydrogen peroxide is then utilized to further remove the lignin, and finally, calcium hypochlorite is used for supplementary bleaching. The yield of bleached pulp is high, moreover, the whiteness of bleached pulp is high, the stability of whiteness is good, and the pollution load of bleaching waste liquor is low.

Description

technical field [0001] The invention belongs to the pulp bleaching process of chemical pulping in the pulp and paper industry, and is an improvement to the CEH bleaching process. The improved bleaching process can be used for bleaching hardwood pulp and non-wood pulp. Background technique [0002] Traditional non-wood fiber pulp and hardwood fiber pulp are mainly produced by the CEH three-stage bleaching process, but the CEH three-stage bleaching process has low bleaching brightness and yield, large pulp viscosity loss, heavy wastewater load, and wastewater AOX seriously exceeds the standard Shortcomings. To this end, the National Development and Reform Commission promulgated in November 2007 the "Paper Industry Development Policy" Chapter IV clearly stipulates that "encourage the development and application of high-yield pulping technology, biotechnology, low-pollution pulping technology, medium-consistency technology, elemental chlorine-free or completely chlorine-free bl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21C9/16D21C9/12
Inventor 谭道诚赵春波曾治国柯友国向克祥
Owner WUHAN CHENMING HANYANG PAPER
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