Method for recovering secondary salts from desulfurization liquid and recycling desulfurization liquid

A desulfurization liquid and secondary salt technology, applied in chemical instruments and methods, copper sulfate, thiocyanic acid, etc., can solve the problems that the secondary salt of the desulfurization liquid cannot be recycled and the desulfurization liquid cannot be effectively recycled, and achieve effective The effect of recycling, reduction of secondary salt content, and low cost

Active Publication Date: 2011-10-26
BEIJING BAIAONA HI TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In order to overcome the defects in the prior art that the auxiliary salt of the desulfurization liquid cannot be recycled and the desulfurization liquid cannot be effectively recycled, the purpose of the present invention is to provide a method for recovering the auxiliary salt of the desulfurization liquid and its recycling

Method used

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  • Method for recovering secondary salts from desulfurization liquid and recycling desulfurization liquid
  • Method for recovering secondary salts from desulfurization liquid and recycling desulfurization liquid

Examples

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Embodiment 1

[0034] 100mL desulfurization solution, containing sodium thiocyanate 165g / L, sodium thiosulfate 72g / L, sodium sulfate 56g / L, temperature 40°C, add CuSO 4 ·5H 2 O 50g, stirred, reacted 60min in reactor 1, filtered to obtain intermediate product CuSCN, containing sodium thiocyanate 2.42g / L in the filtrate, sodium thiosulfate 26.7g / L, sodium sulfate 62.2g / L, thiocyanate The removal rates of sodium and sodium thiosulfate were 98.3% and 56.1%, respectively.

[0035] Add 5g Na to the filtrate 2 SO 4 10H 2 O seed crystal and 20g crystallization accelerator, crystallization accelerator is made up of 5% soda ash and 95% alcohol amine by mass percentage, and alcohol amine is made up of triethanolamine and 50% methyldiethanolamine of mass percentage, stirs, cools Precipitate Na at 0-5°C 2 SO 4 10H 2 O, crystallization time 24-360 hours, crystallization to obtain 12.8gNa 2 SO 4 10H 2 O, the removal rate of sodium sulfate in the desulfurization solution is 72.3%. The clear liqui...

Embodiment 2

[0038] 100mL desulfurization liquid, containing sodium thiocyanate 131g / L, sodium thiosulfate 36.8g / L, sodium sulfate 71.1g / L, temperature 40°C, add CuSO 4 ·5H 2 O 41g, stirred, reacted 60min in reactor 1, filtered to obtain intermediate product CuSCN, containing sodium thiocyanate 1.8g / L in the filtrate, sodium thiosulfate 3.4g / L, sodium sulfate 74.6g / L, thiocyanate The removal rates of sodium and sodium thiosulfate were 98.5% and 89.4%, respectively.

[0039] Add 5g Na to the filtrate 2 SO 4 10H 2 Crystal seed and 30g crystallization accelerator, crystallization accelerator is made up of the alkali of mass percentage 30% and the alcohol amine of 70%, alkali is made up of the caustic soda of mass percentage 50% and the soda ash of 50%, alcohol amine is made up of the three Composed of ethanolamine and 95% methyldiethanolamine, stirred, cooled to 0-5°C to precipitate Na 2 SO 4 10H 2 O, crystallization time 24-360 hours, crystallization to obtain 17.2g Na 2 SO 4 10H 2...

Embodiment 3

[0042] 100mL desulfurization solution, containing sodium thiocyanate 171g / L, sodium thiosulfate 48.6g / L, sodium sulfate 67.7g / L, temperature 40°C, add CuSO 4 ·5H 2 O 50g, stirred, reacted 60min in reactor 1, filtered to obtain intermediate product CuSCN, containing sodium thiocyanate 7.5g / L in the filtrate, sodium thiosulfate 5.86g / L, sodium sulfate 72.4g / L, thiocyanate The removal rates of sodium and sodium thiosulfate were 94.8% and 85.8%, respectively.

[0043] Add 5g seed crystal and 25g crystallization accelerator in the filtrate, the crystallization accelerator is made up of the caustic soda of 20% by mass percentage and the alcohol amine of 80%, and the alcohol amine is made up of the triethanolamine of 95% by mass percent and the methyldiethanolamine of 5% , stirred, cooled to 0-5°C to precipitate Na 2 SO 4 10H 2 O, crystallization time 24-360 hours, crystallization to obtain 16.5gNa 2 SO 4 10H 2 O, the removal rate of sodium sulfate in the desulfurization solut...

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Abstract

The present invention relates to a method for recovering secondary salts from a desulfurization liquid and recycling the desulfurization liquid, which comprises the following steps of: adding CuSO4 to the desulfurization liquid discharged from a wet oxidative desulfurization system for treatment, filtering to obtain CuSCN precipitates and a sulfate solution; adding the CuSCN precipitates to caustic alkali for treatment to recover thiocyanate; and cooling and crystallizing the sulfate solution to recover sulfates and returning the clear liquid to the desulfurization system. The method provided by the present invention simplifies the treatment process of desulfurization liquid wastewater, reduces pollutant emission, recovers the secondary salts from the desulfurization liquid and realizes the recycling of the desulfurization liquid, has a simple process, is environmentally-friendly, realizes the recycling of resources and has a good application prospect.

Description

technical field [0001] The invention relates to the field of desulfurization liquid treatment, in particular to a method for recovering secondary salt from desulfurization liquid and recycling the desulfurization liquid. Background technique [0002] Wet oxidation method has been widely used in the removal of hydrogen sulfide in coal gas, natural gas, coking gas and other gases. Under the action of the oxygen in the air, the hydrogen sulfide is oxidized into elemental sulfur. After the elemental sulfur is recovered, alkali is added to the desulfurization liquid to carry out the next round of hydrogen sulfide absorption and oxidation process. In this way, the absorption liquid containing the catalyst (desulfurization liquid) can be recycled. Currently, all ammonia plants and coke oven gas desulfurization in my country adopt the above desulfurization process. The side reaction of this process is the excessive oxidation of hydrogen sulfide to generate secondary salts such as ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C01C3/20C01G3/10
Inventor 杨军梁黎利杨晓进袁其朋
Owner BEIJING BAIAONA HI TECH
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