Method for recycling lignin from low-boiling alcohol method pulping waste liquor

A technology of low-boiling alcohol method and pulping waste liquid, which is applied in the field of pulping and papermaking engineering, can solve the problems of large investment, secondary pollution, high energy consumption of waste liquid recovery, etc., achieve low energy consumption, reduce recycling energy consumption, reduce The effect of dosage

Active Publication Date: 2013-01-16
DALIAN POLYTECHNIC UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, as we all know, many pulp mills in my country still use traditional pulping methods, waste liquid recycling requires high energy consumption and large investment, and will still cause secondary pollution, which will bring great pressure to the environment and energy.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] A method for recovering lignin from low-boiling alcohol method pulping waste liquid, the pulping waste liquid comes from reed ethanol-water-hydrogen peroxide countercurrent pulping, and the lignin recovery steps are as follows:

[0030] ①Flash dilution: The temperature of the concentrated waste liquid is 170°C, and the ethanol concentration is 45%. After being flashed by the flash tank, the temperature is reduced to 95°C, and the ethanol concentration is reduced to 30%. Dilute with normal temperature industrial water to an ethanol concentration of 18%. , cooled to 20°C by heat exchanger;

[0031] ②Filtration and drying: The precipitated lignin is filtered and dried to obtain lignin, and 100g of reed raw materials harvest lignin of 12g;

[0032] ③ Filtrate treatment: add calcium hydroxide to the filtrate, the addition amount is 4g / L, precipitate, filter, and dry to obtain low-molecular-weight lignin, and 0.4g of low-molecular-weight lignin is harvested from 100g of reed ...

Embodiment 2

[0034] A method for recovering lignin from low-boiling alcohol pulping waste liquid, wherein the pulping waste liquid comes from alkali-catalyzed poplar wood methanol-water pulping, and the lignin recovery steps are as follows:

[0035] ①Flash dilution: The temperature of the concentrated waste liquid is 200°C, and the concentration of methanol is 50%. After being flashed by the flash tank, the temperature drops to 98°C, and the concentration of methanol drops to 30%. Dilute it with industrial water at room temperature until the concentration of methanol is 20%. , cooled to 25°C by heat exchanger;

[0036] ②Filtration and drying: The precipitated lignin is filtered and dried to obtain lignin, and 100g of poplar wood raw material harvests 14g of lignin;

[0037] ③ Filtrate treatment: add calcium hydroxide to the filtrate, the addition amount is 3g / L, precipitate, filter, and dry to obtain low-molecular-weight lignin, and 0.6g low-molecular-weight lignin is harvested from 100g o...

Embodiment 3

[0039] A method for recovering lignin from low-boiling alcohol pulping waste liquid, wherein the pulping waste liquid comes from self-catalyzed poplar ethanol-water pulping, and the lignin recovery steps are as follows:

[0040] ①Flash dilution: the temperature of concentrated black liquor is 205°C, and the ethanol concentration is 55%. After being flashed by the flash tank, the temperature is reduced to 96°C, and the ethanol concentration is reduced to 35%. Dilute to the ethanol concentration with 5% recovered ethanol aqueous solution 15%, cooled to 25°C by heat exchanger;

[0041] ② Filtration and drying: the precipitated lignin is filtered and dried to obtain lignin, and 100g of poplar wood raw material harvests 13g of lignin;

[0042] ③ Filtrate treatment: add calcium hydroxide to the filtrate, the addition amount is 4g / L, precipitate, filter, and dry to obtain low-molecular-weight lignin, and 0.7g of low-molecular-weight lignin is harvested from 100g of poplar raw materia...

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Abstract

The invention relates to a method for recycling lignin from low-boiling alcohol method pulping waste liquor, which relates to the technical field of pulping papermaking engineering. The method for recycling the lignin from the low-boiling alcohol method pulping waste liquor is applicable to the waste liquor which is obtained by boiling reagent of plant raw materials with low-boiling alcohols, the waste liquor is processed in steps such as flash evaporation, diluting, cooling, precipitation, filtering, separating, drying and the like to obtain lignin, calcium hydroxide is added in filter liquor, and the precipitate is filtered, separated and dried again to obtain low-molecule lignin. The method has characteristics of high recycling rate, less investment, no pollution and low energy consumption.

Description

technical field [0001] The invention relates to a method for recovering lignin from low-boiling alcohol pulping waste liquid, and relates to the technical field of pulping and papermaking engineering. Background technique [0002] As the economy takes off, China's demand for pulp and paper is increasing rapidly. However, as we all know, many pulp mills in my country still use traditional pulping methods. Waste liquid recycling requires high energy consumption and large investment, which will still cause secondary pollution and bring great pressure to the environment and energy. Therefore, in my country's "11th Five-Year Plan for Pulp and Papermaking", the development of clean pulp production technology has been listed as a key content. In view of this, finding a new pulping method that can effectively recover useful substances such as lignin and better protect the environment has become an urgent problem to be solved in the paper industry. [0003] The organic solvent pulp...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21C11/00C07G1/00C08H7/00
Inventor 平清伟张健尉志苹石海强李娜牛梅红田兰强樊瑞霞胡欢
Owner DALIAN POLYTECHNIC UNIVERSITY
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