Method for lignin extraction by papermaking black liquor acidification and flocculation precipitation

A technology for biological acidification and papermaking black liquor, applied in the fields of resources and environment, can solve the problems of high cost of foreign inorganic acid or organic acid, increase the difficulty and cost of treatment, and high cost, achieve good social significance and economic value, and enhance the follow-up treatment. Features, the effect of reducing processing costs

Inactive Publication Date: 2008-12-24
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Direct evaporative drying not only consumes a lot of energy and high cost, but also the obtained lignin product has high impurity components and low commodity characteristics
Inorganic acid precipitation and precipitation to extract lignin, although lignin has high purity, on the one hand, it consumes a large amount of external inorganic acid or organic acid, and the cost is high. On the other hand, the input of inorganic acid causes secondary pollution and increases the difficulty and cost of subsequent treatment.
The direct flocculation precipitation method requires two major chemicals such as flocculants, which is costly, and the precipitated lignin impurities have no commercial value

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Example 1: A small papermaking enterprise produces lignin with black liquor

[0021] (1) 10 cubic meters of papermaking black liquor that produces a pH value of 11.28 every day is stored in a black liquor storage container, and the content of black liquor lignin is 8.2597g / L;

[0022] (2) Add 3.6 tons (dry weight) of chopped straw in the biological acidification reaction device of 100 cubic meters, inoculate biogas residue, the addition of biogas residue is 360kg (moisture content is 80%), add water 90 cubic meters, Fermentation at room temperature, after 5 days of reaction, the pH value of the fermentation broth dropped to 5.32, and the VFA concentration was 40mol / L in terms of acetic acid;

[0023] (3) Extract 50 cubic meters of fermented liquid from the acidification reactor in step (2) and store it in the fermented acid liquid storage container, and the extraction cycle is 1 time / day;

[0024] (4) black liquor in step (1) and fermented sour liquor in step (3) are p...

Embodiment 2

[0028] Example 2: A medium-sized paper mill produces lignin with papermaking black liquor

[0029] (1) The papermaking black liquor that this enterprise produces every day 1000 tons of pH value is 12.35 is stored in the black liquor storage pond, and the content of black liquor lignin is 10.8865g / L;

[0030] (2) 10.2 tons (dry weight) of Spartina alterniflora of throwing chopping are in 300 cubic meters of biological acidification reactors, inoculate municipal sludge 1200kg (water content 78%), add water 270 cubic meters, ferment under normal temperature;

[0031] (3) construct 19 biological acidification reaction systems again by the method of step (2);

[0032] (4) drop to 5.50 through 5 days reaction to the pH value of fermented liquid, VFA concentration is 50mol / L in acetic acid,

[0033] (5) extract 180 cubic meters of fermented liquid from each biological acidification reaction device in turn and enter in the fermented acid liquid storage tank;

[0034] (6) the black l...

Embodiment 3

[0038] Example 3: A large paper mill produces lignin

[0039] (1) Get 8000 tons of papermaking black liquor with a pH value of 12.65 and store it in the black liquor storage tank, and the content of black liquor lignin is 11.563g / L;

[0040] (2) throw 90 tons (dry weight) of chopped wheat straw in 2800 cubic meters of biological acidification reactors, inoculate 10 tons of municipal sludge (water content 78%), add 2600 cubic meters of water, and ferment under normal temperature,

[0041] (3) Build 9 biological acidification reaction systems by the method of step (2)

[0042] (4) drop to 5.20 through 5 days reaction to the pH value of fermented liquid, VFA concentration is 36mol / L in terms of acetic acid,

[0043] (5) Extract 2400 cubic meters of fermented liquid from each biological acidification reaction device successively and enter in the fermented acid liquid storage tank;

[0044] (6) the black liquor in step (1) and the fermented sour liquor in step (5) are pumped in 1...

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PUM

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Abstract

The invention relates to a method for extracting lignin via paper liquor biological acidification-flocculation deposition, wherein said method comprises: the paper liquor is stored into the liquor storage; adding solid organic into biological acidification reaction container, to ferment and generate organic acid liquid, while the ferment temperature is 2-40Deg. C for 4-5 days; when the pH value of ferment liquid in the reaction container is reduced to 5-6; and the volatile fatty acid number (VFA) is 2-80mol / L at acetic acid density, to pump the acid liquid into the ferment acid liquid storage; mixing the liquor with the ferment acid liquid, depositing, and entering into the container, and discharging some; dewatering the deposit, drying to obtain the lignin.

Description

technical field [0001] The invention belongs to the technical field of resources and environment, and in particular relates to a method for extracting lignin from papermaking black liquor through biological acidification-flocculation precipitation. Background technique [0002] my country is one of the countries that first invented papermaking technology, and it is also a big country in papermaking. However, my country's papermaking industry still uses traditional production processes, mainly alkaline method, sulfurous acid method, neutral sub-sale method and semi-chemical method, etc. A large amount of black liquor is discharged during the pulping and cooking process of several traditional paper pulping technologies, which seriously pollutes the local surface water body. At present, most of the rivers and lakes in our country are polluted or threatened by pollution. Among the pollution sources, the contribution of the paper industry is more prominent. Serious environmental...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D21C11/00
Inventor 朱洪光王彪陈小华朱鹏
Owner TONGJI UNIV
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