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Circular treatment method of acid filtrate from pulping black liquor

A technology for recycling and pulping black liquor, which is applied in the field of pulping and papermaking, can solve the problems of large concentration of dilute black liquor, large evaporation of dilute black liquor, and inability to recover lignin, so as to avoid evaporation energy consumption and save energy Consumption and material consumption, the effect of small investment

Active Publication Date: 2013-01-16
GUANGXI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Disadvantages of burning black liquor: (1) The concentration of dilute black liquor is large. For every ton of pulp produced, 7-9 tons of dilute black liquor will be produced.
At present, the combined application technology of black liquor gasification and gasification is still in the experimental stage. At the same time, black liquor gasification also has the disadvantages of large evaporation of dilute black liquor and inability to recover lignin in black liquor.

Method used

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  • Circular treatment method of acid filtrate from pulping black liquor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Such as figure 1 , a kind of circulating treatment method of pulping black liquor acidification filtrate, comprises the following steps:

[0051] a. Acidic filtrate alkalization: import the acidic filtrate into the acidic filtrate alkalization pool 1, add recovered lye to adjust the pH value to 12, and obtain the alkalized filtrate;

[0052] b. filtrate circulation cooking: the alkalized filtrate is transferred to the cooking pot 2 to become a part of the cooking liquid, adding wood chips, water, recovered lye and anthraquinone and other chemical additives, feeding water steam for cooking, the cooking temperature is 140 ° C, and the temperature is raised The time is 60 minutes, and the holding time is 120 minutes. The slurry produced by cooking is extracted and separated with the black liquor extractor 3 to obtain primary color pulp and dilute black liquor;

[0053] c. Evaporation and concentration of the dilute black liquor: transport the dilute black liquor to the e...

Embodiment 2

[0060] Such as figure 1 , a kind of circulating treatment method of pulping black liquor acidification filtrate, comprises the following steps:

[0061] a. Acidic filtrate alkalization: import the acidic filtrate into the acidic filtrate alkalization pool 1, add recovered lye to adjust the pH value to 9, and obtain the alkalized filtrate;

[0062] b. Filtrate circulation cooking: the alkalized filtrate is transferred to the cooking pot 2 to become a part of the cooking liquid, adding wood chips, water, recycled lye and anthraquinone and other chemical additives, feeding water steam for cooking, the cooking temperature is 180 ° C, and the temperature is raised The time is 90 minutes, and the holding time is 90 minutes. The slurry produced by cooking is extracted and separated by the black liquor extractor 3 to obtain primary color pulp and dilute black liquor;

[0063] c. Evaporation and concentration of the dilute black liquor: transport the dilute black liquor to the evapor...

Embodiment 3

[0070] Such as figure 1 , a kind of circulating treatment method of pulping black liquor acidification filtrate, comprises the following steps:

[0071] a. Acidic filtrate alkalization: import the acidic filtrate into the acidic filtrate alkalization pool 1, add recovered lye to adjust the pH value to 11, and obtain the alkalized filtrate;

[0072] b. Filtrate circulation cooking: the alkalized filtrate is transferred to the cooking pot 2 to become a part of the cooking liquid, adding chemical additives such as wood chips, water, recovered lye and green oxygen, and feeding water steam for cooking. The cooking temperature is 165 ° C, and the temperature is raised The time is 80 minutes, and the holding time is 100 minutes. The slurry produced by cooking is extracted and separated with the black liquor extractor 3 to obtain primary color pulp and dilute black liquor;

[0073] c. Evaporation and concentration of the dilute black liquor: transport the dilute black liquor to the ...

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Abstract

The invention discloses a circular treatment method of acid filtrate from pulping black liquor. The circular treatment method includes the steps of alkalifying the acid filtrate, circularly digesting the filtrate, evaporating and concentrating dilute black liquor, combusting the black liquor, oxidizing alkali fusant, preparing sulfuric acid, dissolving oxidation residue of the alkali fusant, and alkalifying green liquor. The acid filtrate from the pulping black liquor is alkalified and used as digestion liquor, the black liquor is combusted to obtain the alkali fusant, and the sulfuric acid is produced by oxidative conversion, SO2 catalytic oxidation and SO3 absorption steps. By the circular treatment method, sulfuric acid, alkali liquor and heat can be recovered from the acid filtrate generated in lignin extraction of the pulping black liquor and are recycled in a system. Energy consumption and material consumption are reduced greatly. Based on existing equipment and techniques of pulp mills, input in process modification is low.

Description

technical field [0001] The invention belongs to the technical field of pulping and papermaking, and relates to the treatment of papermaking sewage, in particular to a method for circulating and treating pulping black liquor acidification filtrate. Background technique [0002] Pulping black liquor is a viscous liquor produced during the chemical pulping process. The black liquor contains a large amount of organic matter, the organic matter included is mainly alkali lignin, and also includes sodium hexa(or pentanoate), sodium acetate and sodium formate. Corresponding to different concentrations of black liquor, its total COD (chemical oxygen demand, definition: the mass of oxygen element required for the complete oxidation of substances contained in a unit volume of wastewater) reaches 38400-1426000mgl -1 , is a potential source of water pollution, and any discharge will cause serious pollution. At the same time, the calorific value of black liquor solids is 1.4-1.6MJ / kg, wh...

Claims

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Application Information

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IPC IPC(8): D21C11/04D21C5/00
CPCY02P70/10
Inventor 农光再鲁炳辰李世强
Owner GUANGXI UNIV