Wheat straw pulp black liquor alkali recovery method

A recovery method and black liquor caustic soda technology can be applied in the combustion of pulping waste liquid, regeneration of pulping liquid, and concentration of waste liquid, etc. The effect of organic dye load, reducing high-load pollution and reducing pollution load

Inactive Publication Date: 2016-05-18
常州市精尔锐工具制造有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are certain deficiencies in the existing recovery methods of papermaking black liquor: project investment and operating costs are high, and pulp mills with an annual output of more than 17,000 tons of pulp can realize meager profit operation; wheat straw black liquor has low ca...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] A method for recovering wheat straw pulp black liquor alkali, comprising the following steps:

[0014] 1) In the black liquor evaporation and concentration section, a five-effect full-plate evaporator is used to evaporate and concentrate the black liquor, and the evaporation intensity is 10kg water / m 2 h, concentration of thick black liquor after evaporation is 40%%; evaporation area of ​​evaporator is 6200m 2 .

[0015] 2) The black liquor combustion section, the concentrated black liquor obtained in the above step 1) is further evaporated and concentrated by the disc evaporator using three winds, then enters the alkali furnace for cracking and combustion, and finally goes to the dissolution tank to make green liquor, and the alkali furnace The furnace temperature is 500°C, the furnace pressure is 0MPa, the primary and secondary air temperatures are 280°C, the primary air pressure is 600Pa, the secondary air pressure is 800Pa, and the third air pressure is 1000Pa;

...

Embodiment 2

[0018] A method for recovering wheat straw pulp black liquor alkali, comprising the following steps:

[0019] 1) In the black liquor evaporation and concentration section, a five-effect full-plate evaporator is used to evaporate and concentrate the black liquor, and the evaporation intensity is 11kg water / m 2 h, concentration of thick black liquor after evaporation is 44%; evaporation area of ​​evaporator is 6200m 2 .

[0020] 2) The black liquor combustion section, the concentrated black liquor obtained in the above step 1) is further evaporated and concentrated by the disc evaporator using three winds, then enters the alkali furnace for cracking and combustion, and finally goes to the dissolution tank to make green liquor, and the alkali furnace The furnace temperature is 600°C, the furnace pressure is 20MPa, the primary and secondary air temperatures are 290°C, the primary air pressure is 800Pa, the secondary air pressure is 1000Pa, and the third air pressure is 1500Pa;

...

Embodiment 3

[0023] A method for recovering wheat straw pulp black liquor alkali, comprising the following steps:

[0024] 1) In the black liquor evaporation and concentration section, a five-effect full-plate evaporator is used to evaporate and concentrate the black liquor, and the evaporation intensity is 10.5kg water / m 2 h, concentration of thick black liquor after evaporation is 40%~44%; evaporation area of ​​evaporator is 6200m 2 .

[0025] 2) The black liquor combustion section, the concentrated black liquor obtained in the above step 1) is further evaporated and concentrated by the disc evaporator using three winds, then enters the alkali furnace for cracking and combustion, and finally goes to the dissolution tank to make green liquor, and the alkali furnace The furnace temperature is 550°C, the furnace pressure is 10MPa, the primary and secondary air temperatures are 285°C, the primary air pressure is 700Pa, the secondary air pressure is 900Pa, and the third air pressure is 1200P...

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PUM

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Abstract

The invention discloses a wheat straw pulp black liquor alkali recovery method. The method includes the following steps that firstly, black liquor is evaporated and concentrated, and the concentration of the concentrated black liquor is 40-44% after evaporation; secondly, the concentrated black liquor obtained after evaporation is further evaporated and concentrated through tertiary air by means of a disk evaporator and then enters an alkali furnace to be pyrolysed and combusted, and finally green liquor is prepared in a dissolving tank; thirdly, the green liquor is processed in a causticizing department, the green liquor obtained in the second step and an excessive amount of ash are placed in a causticizing devuce, causticizing temperature is higher than 95 DEG C, and white liquor is obtained after filtration. According to the method, the technological process is simple, investment is small, and lignin is recycled while organic matter dyeing loads are reduced, wherein the concentration of the green liquor is 110-120 g/L, the amount of the excessive amount of ash is 3-5%, the causticizing degree is larger than 85%, the amount of white mud residual alkali is smaller than 2%, the dryness degree of white mud is larger than 50%, and the concentration of the white liquor is larger than 80g/L.

Description

technical field [0001] The invention relates to the field of alkali recovery of papermaking black liquor, in particular to a method for alkali recovery of wheat straw pulp black liquor. Background technique [0002] Environmental pollution caused by the paper industry has long troubled people. In papermaking wastewater, black liquor is the main source of pollution. The direct discharge of papermaking black liquor into rivers and oceans will cause eutrophication in local waters and destroy the original ecological balance. As a result, it has a notorious reputation for polluting the environment. The so-called papermaking black liquor is the alkaline black liquor left after extracting and separating the cellulose that can be used to make paper in plants. Papermaking black liquor is mainly composed of lignin and hemicellulose. These two components function similarly to cellulose, and together they support the plant's cell walls. However, lignin and hemicellulose are far les...

Claims

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Application Information

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IPC IPC(8): D21C11/04D21C11/10D21C11/12D21C11/00
CPCD21C11/04D21C11/0064D21C11/10D21C11/12
Inventor 周文斌
Owner 常州市精尔锐工具制造有限公司
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