Alkali recovery process for black liquor of straw pulp

A straw pulp black liquor and new process technology, applied in the field of environmental technology and electrochemistry, can solve the problems of limited application range, difficult anode materials, easy wear and tear, etc., and achieve the effect of continuity

Inactive Publication Date: 2002-02-06
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the use of electrodialysis to treat black liquor often encounters the following problems: ①The alkali recovery rate and recovery concentration are low, and the power consumption is high; The operation is cumbersome and the

Method used

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  • Alkali recovery process for black liquor of straw pulp
  • Alkali recovery process for black liquor of straw pulp
  • Alkali recovery process for black liquor of straw pulp

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] In the case of electronic peristaltic pump enhanced circulation, the black liquor is firstly subjected to ion exchange membrane diffusion dialysis for 100 minutes. The dilute lye obtained is used as the electrolyte in the cathodic chamber of the electrodialysis process, and the black liquor treated by diffusion dialysis is used as the electrolyte in the anode chamber of the electrodialysis. The electrolysis is performed at a constant current of 1A for 120 minutes, and the distance between the cathode and the anode is 2 cm. The results are shown in Table 1.

[0016]

project

Raw black liquor

Diffusion dialysis

100min

Diffusion dialysis

100min

+Electrodialysis

120min

CODCr(mg / L)

37675.2

32400.67

Removal rate 14.0%

36582.20

Removal rate 29.7%

Na + (g / L)

7.68

6.996

Recovery rate 8.9%

3.504

Recovery rate 54.4%

[0017] It can be seen fro...

Embodiment 2

[0021] In the case of enhanced circulation by electronic peristaltic pump, the black liquor is firstly subjected to diffusion dialysis by hydrophobic fluorine membrane for 100 minutes. The dilute lye obtained is used as the electrolyte in the cathodic chamber of the electrodialysis process, and the black liquor treated by diffusion dialysis is used as the electrolyte in the anode chamber of the electrodialysis. The electrolysis is performed at a constant current of 1A for 120 minutes, and the distance between the cathode and the anode is 2 cm. The results are shown in Table 2.

[0022]

[0023] It can be seen from the figure that after the black liquor undergoes diffusion dialysis, the COD Cr The removal rate was 16.3%, and the recovery rate of NaOH was 13.4%. After combined treatment with electrodialysis, about 59.3% of NaOH was recovered. + , and has a COD of 31.1% Cr removal rate.

Embodiment 3

[0025] In the case of electronic peristaltic pump enhanced circulation, the black liquor is firstly subjected to diffusion dialysis of hydrophilic fluorine membrane for 100 minutes. The dilute lye obtained is used as the electrolyte in the cathodic chamber of the electrodialysis process, and the black liquor treated by diffusion dialysis is used as the electrolyte in the anode chamber of the electrodialysis. The electrolysis is performed at a constant current of 1A for 120 minutes, and the distance between the cathode and the anode is 2 cm. The results are shown in Table 3.

[0026]

project

stock solution

Diffusion dialysis

100min

Diffusion dialysis

100min

+Electrodialysis

120min

Remark

COD Cr (mg / L)

37675.2

31182.24

Removal rate 17.2%

25170.24

Removal rate 33.19%

Na + (g / L)

7.68

6.530

Recovery rate 15.0%

3.052

Recovery rate ...

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PUM

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Abstract

An alkali recovering process for the black liquor of straw pulp includes diffusion dialysis of digested black liquor to obtain diluted alkali solution, dividing electric dialysis chamber into anode and cathode chambers by monocational diaphragm, circulating black liquor in anode chamber, circulating diluted alkali solution in cationde chamber, electric dialysis at ordinary temp and pressure by applying 8-10 v DC voltage and 1 A current, acid separating, biochemical treating, and electrically catalytic oxidization. Its advantages are high recovery yield of alkali, and low energy consumption.

Description

Technical field: [0001] The invention relates to a new process for alkali recovery and treatment of straw pulp black liquor. The black liquor diffusion dialysis treatment process is added before electrodialysis to realize the continuity of the alkali recovery process and improve the alkali recovery efficiency. It belongs to the field of environmental technology and electrochemistry. Background technique: [0002] The paper industry has a large amount of wastewater discharge, which contains a large amount of cellulose, lignin and corresponding chemicals, and has a large oxygen consumption. Among them, the pollution of cooking black liquor is the most serious, accounting for 90% of the pollution in the whole paper industry. At present, the common methods for treating this kind of wastewater at home and abroad include traditional alkali recovery method, acid analysis method, flocculation sedimentation method and anaerobic treatment method. The traditional alkali recovery meth...

Claims

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Application Information

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IPC IPC(8): C02F1/44D21C11/04
Inventor 贾金平叶建昌王亚林
Owner SHANGHAI JIAO TONG UNIV
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