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A method for cleaning and bleaching eucalyptus dissolving pulp

A technology of dissolving pulp and eucalyptus wood, applied in the field of cleaning and bleaching of eucalyptus dissolving pulp, can solve the problems of large amount of waste water, reduce water consumption and waste water volume, waste water pollution, etc., and achieve large pollution load, light pollution load and market competition. strong effect

Active Publication Date: 2014-10-22
SHANDONG TAIYANGZHIYE +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that the amount of waste water produced is large, the waste water pollution is serious, and the waste water contains a large amount of Cl - , has a great impact on biochemical treatment. Using conventional physical methods, chemical methods, or a combination of biological and biochemical methods to treat wastewater, it is difficult to discharge wastewater up to standard, and there is internationally recognized carcinogen Dioxin.
[0004] For the pulp and paper industry, medium-concentration bleaching technologies such as oxygen delignification, chlorine dioxide, and hydrogen peroxide are used in the bleaching section, which greatly reduces water consumption and waste water, and does not produce adsorbable organic chloride AOX, which has no impact on the environment. Small, can achieve strict discharge standards, but this bleaching method does not consider the characteristics of dissolving pulp bleaching, such as: pentose oligosaccharide content, high α-cellulose content, good reaction performance and other factors

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] A cleaning and bleaching method for eucalyptus dissolving pulp comprises the following steps:

[0031] a. Two-stage oxygen delignification: after the eucalyptus dissolving pulp produced by the continuous prehydrolysis kraft process is concentrated by a drum displacement washing machine, it passes through a medium-consistency pump and a medium-consistency mixer in turn, and enters an upflow oxygen bleaching tower After the pulp comes out of the top of the tower, it passes through the booster pump and enters the second upflow oxygen bleaching tower. The NaOH dosage in the two oxygen delignification stages is 2.8%, the oxygen dosage is 3.5%, the pulp mass concentration is 10.0%, and the temperature The temperature is 90°C, the pressure at the top of the tower is 0.5MPa, the oxygen removal time of the first stage is 15 minutes, and the oxygen removal time of the second stage is 50 minutes;

[0032] b. Chlorine dioxide bleaching under strong acid conditions: the pulp after t...

Embodiment 2

[0038] A method for cleaning and bleaching eucalyptus dissolving pulp, comprising the following steps:

[0039] a. Two-stage oxygen delignification: after the eucalyptus dissolving pulp produced by the continuous prehydrolysis kraft process is concentrated by a drum displacement washing machine, it passes through a medium-consistency pump and a medium-consistency mixer in turn, and enters an upflow oxygen bleaching tower After the pulp comes out of the top of the tower, it passes through the booster pump and enters the second upflow oxygen bleaching tower. The NaOH dosage in the two oxygen delignification stages is 2.5%, the oxygen dosage is 3.8%, the pulp mass concentration is 11.0%, and the temperature The temperature is 95°C, the pressure at the top of the tower is 0.5MPa, the oxygen removal time of the first stage is 15 minutes, and the oxygen removal time of the second stage is 50 minutes.

[0040] b. Chlorine dioxide bleaching under strong acid conditions: the pulp after...

Embodiment 3

[0046] A method for cleaning and bleaching eucalyptus dissolving pulp, comprising the following steps:

[0047] a. Two-stage oxygen delignification: after the eucalyptus dissolving pulp produced by the continuous prehydrolysis kraft process is concentrated by a drum displacement washing machine, it passes through a medium-consistency pump and a medium-consistency mixer in turn, and enters an upflow oxygen bleaching tower , after the pulp comes out of the top of the tower, it passes through the booster pump and enters the second upflow oxygen bleaching tower. The NaOH dosage in the two oxygen delignification stages is 3.0%, the oxygen dosage is 4.0%, the pulp mass concentration is 10.0%, and the temperature The temperature is 100°C, the pressure at the top of the tower is 0.5MPa, the oxygen removal time of the first stage is 15 minutes, and the oxygen removal time of the second stage is 50 minutes.

[0048] b. Chlorine dioxide bleaching under strong acid conditions: the pulp a...

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Abstract

The invention relates to the field of a method for cleaning and bleaching eucalyptus dissolving pulp, in particular to the method for cleaning and bleaching the eucalyptus dissolving pulp. The method comprises the following steps of: bleaching with chlorine dioxide under the condition of two sections of oxygen delignification and strong acid, performing alkali extraction reinforced by oxygen and hydrogen peroxide, bleaching with chlorine dioxide, and treating with xylanase after bleaching, namely treating the pulp with a biological enzyme, wherein 80 to 120ml of the xylanase is used in each ton of pulp, the pH value of the pulp is adjusted to be 6.0 to 7.0, the temperature is 50 to 80 DEG C, the time is 30 to 60 minutes, and the concentration of the pulp is 9.0 to 12.0 percent, and washing the pulp by a pulp washer, and performing acid treatment in a pulp tower. The method has the advantages that: the waste water amount is reduced by 60 percent compared with that of the traditional method; the waste water does not contain adsorbable organic halides (AOX); the pollution is low; and the produced eucalyptus dissolving pulp is environment friendly, can be widely applied to the fields of foods, medicaments, textiles and the like and is high in market competitiveness.

Description

technical field [0001] The invention relates to the field of a cleaning and bleaching method for dissolving pulp, in particular to a cleaning and bleaching method for eucalyptus dissolving pulp. Background technique [0002] With the development of viscose fiber and cellulose derivatives industry, especially the development of viscose staple yarn, the market demand for dissolving pulp is increasing. The raw materials for producing dissolving pulp are mainly cotton linters, wood and bamboo. Due to the year-by-year decline in cotton planting area, the cultivation of new seedless cotton and the increase in labor costs, the output of cotton linters has also declined year by year, and the price fluctuates greatly. Eucalyptus The advantage of wood as a raw material for dissolving pulp is that it is a renewable resource with high cellulose content, fast growth, easy management, and abundant resources, and it becomes a raw material for dissolving pulp. [0003] However, the traditi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D21C9/00D21C9/10D21C9/147D21C9/14D21C9/16
Inventor 应广东陈克复刘泽华刘延波乔军翟丙彦张伟梁洪金钟洪霞杨江红
Owner SHANDONG TAIYANGZHIYE
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