Black liquor treatment method combining lignin extraction and synthesis gas production

A treatment method and synthesis gas technology, applied in fiber raw material treatment, lye regeneration, textile and papermaking, etc., can solve the problems of large evaporation of dilute black liquor, large concentration of dilute black liquor, and inability to recover lignin, etc. Achieve the effect of reducing energy consumption and reducing evaporation energy consumption

Active Publication Date: 2013-02-27
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.
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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  • Black liquor treatment method combining lignin extraction and synthesis gas production

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Comparison scheme
Effect test

Embodiment 1

[0044] Such as figure 1 , a kind of black liquor processing method that lignin extraction combines syngas production, comprises the following steps:

[0045] a. Lignin extraction: extract and separate the slurry produced by cooking in the cooking pot 1 with the black liquor extractor 2 to obtain dilute black liquor and primary color pulp, and import the dilute black liquor with 50% by weight into the black liquor acidification pool 3. Add sulfuric acid to adjust the pH value to 4, precipitate the lignin, and filter it with a vacuum filter 4 to obtain lignin and acidic filtrate;

[0046] b. Acidic filtrate recycling: a part of the acidic filtrate is introduced into the filtrate alkalization pool 5, and its volume is equal to that of the dilute black liquor entering the black liquor acidification pool 3. After alkalization with alkali (pH is 10), the circulation Put it into cooking pot 1 for cooking, add wood chips, water, recovered lye and anthraquinone and other chemical add...

Embodiment 2

[0054] Such as figure 1 , a kind of black liquor processing method that lignin extraction combines syngas production, comprises the following steps:

[0055] a. Lignin extraction: extract and separate the slurry produced by cooking in the cooking pot 1 with the black liquor extractor 2 to obtain dilute black liquor and primary color pulp, and import the dilute black liquor with a weight percentage of 30% into the black liquor acidification pool 3. Adding sulfuric acid to adjust the pH value to 3, causing the lignin to precipitate, and filtering with a vacuum filter 4 to obtain the lignin and the acidic filtrate;

[0056] b. Acidic filtrate recycling: a part of the acidic filtrate is introduced into the filtrate alkalization pool 5, and its volume is equal to the dilute black liquor entering the black liquor acidification pool 3. Put it into cooking pot 1 for cooking, add wood chips, water, recovered lye and anthraquinone and other chemical additives, feed water steam for coo...

Embodiment 3

[0064] Such as figure 1 , a kind of black liquor processing method that lignin extraction combines syngas production, comprises the following steps:

[0065] a. Lignin extraction: the slurry produced by cooking in the cooking pot 1 is extracted and separated by the black liquor extractor 2 to obtain dilute black liquor and primary color pulp, and the dilute black liquor with a weight percentage of 40% is introduced into the black liquor acidification pool 3. Adding sulfuric acid to adjust the pH value to 2, causing lignin to precipitate out, and filtering with vacuum filter 4 to obtain lignin and acidic filtrate;

[0066] b. Acidic filtrate recycling: a part of the acidic filtrate is introduced into the filtrate alkalization pool 5, and its volume is equal to that of the dilute black liquor entering the black liquor acidification pool 3. Put it into cooking pot 1 for cooking, add wood chips, water, recycled lye and green oxygen and other chemical additives, feed water steam ...

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Abstract

The invention discloses a black liquor treatment method combining lignin extraction and synthesis gas production. The method comprises the following steps: lignin extraction, acidic filtrate recycling, dilute black liquor evaporation and concentration, black liquor gasification, alkali fusant dissolution, green liquor causticization, gasified gas desulfurization, and sulfuric acid preparation. Dilute black liquor produced by boiling is divided into two parts; 30-50 wt% of the dilute black liquor is subjected to lignin extraction; part of the acidic filtrate generated from lignin extraction separation is used for acidification of the dilute black liquor, and the other part is subjected to alkalization, and used as a cooking liquor; 50-70 wt% of the dilute black liquor is conveyed into an evaporator for concentration to obtain 60-75% strong thick black liquor, which is sprayed into a gasification furnace for gasification, so as to obtain alkali liquor containing sodium hydroxide and sodium sulfide, and sulfuric acid. The method provided by the invention can recycle lignin (extraction rate of 30-50%) and alkaline substances (recycling rate of 80-90%) from the black liquor, produce synthesis gas and sulfuric acid for recycling within the system, and save energy by 5-10%.

Description

technical field [0001] The invention belongs to the technical field of pulping and papermaking, and relates to papermaking sewage treatment, in particular to a black liquor treatment method in which lignin extraction is combined with synthesis gas production. Background technique [0002] Pulping black liquor is viscous liquor produced by chemical pulping process. 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
Inventor 农光再鲁炳辰李世强
Owner GUANGXI UNIV
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