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Process for recycling inorganic salt from wastewater for desulfurization and decyanation of coke oven gas

A technology of desulfurization, decyanation and coke oven gas, which is applied in the field of coal coking, can solve the problems of low product recovery rate, waste water, waste residue generation, waste water salt separation, etc., and achieve scientific and reasonable process flow, huge social benefits, and easy The effect of control

Active Publication Date: 2009-04-08
JINNENG SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0020] Therefore, although there have been many studies and reports on the treatment of desulfurization and decyanation wastewater, the NH 4 CNS / (NH 4 ) 2 S 2 o 3 Wastewater with a (wt) ratio > 1 or 4 The recovery of CNS lacks the systematic separation of mother liquor (NH 4 ) 2 S 2 o 3 and (NH 4 ) 2 SO 4 The process of the finished product, the product not only has a low recovery rate, but also produces waste water and waste residue
In particular, in the prior art, no consideration was given to (NH 4 ) 2 S 2 o 3 While crystallizing NH 4 CNS is easy to precipitate and form mixed crystals, which cannot achieve the purpose of salt separation in wastewater
In addition, the application of the ternary phase diagram has relatively high requirements for operating parameters, which is not conducive to the implementation of industrialization

Method used

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  • Process for recycling inorganic salt from wastewater for desulfurization and decyanation of coke oven gas
  • Process for recycling inorganic salt from wastewater for desulfurization and decyanation of coke oven gas
  • Process for recycling inorganic salt from wastewater for desulfurization and decyanation of coke oven gas

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Experimental program
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Effect test

Embodiment 1

[0056] refer to figure 1 The process flow shown.

[0057] Coke oven gas desulfurization and decyanation wastewater 4000Kg (solid content 34.1%. Wherein NH 4 CNS content 19.8%, (NH 4 -) 2 S 2 o 3 content 12.1%), put it into a 5000-liter enamel kettle, heat it under vacuum conditions for dehydration and concentration, the concentration temperature is 82°C, remove 2200Kg of water, stop the heating, stop the vacuum, add 15Kg of activated carbon to decolorize at 75-80°C After 0.5h, perform hot filtration (use 75°C hot water to keep the filter warm). The obtained filter residue is washed with a small amount of waste water to obtain the washed 1 # Wet filter residue 26Kg ((NH 4 ) 2 SO 4 filter residue). The obtained clarified filtrate was stirred, cooled and crystallized, and when the temperature dropped to 18±2°C, it was kept at a constant temperature for 1h, and centrifugally filtered with a centrifuge to obtain 1 # The amount of mother liquor is about 1080L (of which, N...

Embodiment 2

[0059] refer to figure 2 The process flow shown.

[0060] 2000kg is concentrated through embodiment 1 method, crystallization is separated NH 4 1 of CNS products # Mother liquor and 2 circulating in the system # Mixed solution of mother liquor (solid content 65.1%, where NH 4 CNS content 27.3%, (NH 4 ) 2 S 2 o 3 content 34.6%), put it into a 3000-liter enamel kettle, heat it with steam, and carry out dehydration and concentration under vacuum. When the temperature dropped to 53°C, add 10Kg2 # Filter residue (the first batch of available industry (NH 4 ) 2 S 2 o 3 ), keep stirring at a temperature of 49-55°C for 2h to complete the slagging. Then carry out hot filtration (use 53 ℃ of hot water to filter to keep warm), and wash filter residue with a small amount of 50 ℃ of waste water, obtain 2 # Filter residue 507Kg ((NH 4 ) 2 S 2 o 3 Filter residue, (NH 4 ) 2 S 2 o 3 Content 72.6%, NH 4 CNS content 6.2%, water content 10.1%, etc.) and clear filtrate. Wi...

Embodiment 3

[0062] Refer to attached image 3 The process flow shown.

[0063] Coke oven gas desulfurization and decyanation wastewater 2000Kg (solid content 38.6%, of which NH 4 CNS content 15.2%, (NH 4 ) 2 S 2 o 3 Content 16.4%) and 3 circulating in the system # Mother liquor 1000Kg (solid content 67.3%, of which NH 4 CNS content 25.2%, (NH 4 ) 2 S 2 o 3 content 35.3%) into a 3000-liter enamel kettle, heated with steam, dehydrated in a vacuum state, the concentration temperature was 82°C, and 1050Kg of water was removed. After the concentration was completed, stop heating and vacuum, add 10Kg of activated carbon at 65-80°C Cool down after 0.5h of decolorization treatment, when the temperature drops to 55°C, add 15Kg 3 # Filter the residue for slag analysis, and keep stirring at a temperature of 48-53°C for 2 hours to complete the slag analysis. Carry out hot filtration then (with 52 ℃ of hot waters, filter is kept warm), and wash filter residue with a small amount of 50 ℃ of...

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Abstract

The invention provides a process for reclaiming inorganic salt from wastewater in the desulphurization and decyanation of coal gas of a coke furnace. The process aims at reclaiming ammonium thiocyanate (NH4CNS), ammonium thiosulfate ((NH4)2S2O3) and ammonium sulphate ((NH4)2SO4) from wastewater produced by a liquid-phase catalytic oxidation, desulphurization and decyanation process taking ammonia as an alkaline resource. In particular, the process comprises that the wastewater and a mother solution with the ratio of NH4CNS to (NH4)2S2O3 more than or equal to 1.0 (wt) and the ratio of NH4CNS to (NH4)2S2O3 less than 1.0 (wt) are separated to obtain finished products of NH4CNS, (NH4)2S2O3 and (NH4)2SO4 through a targeted process. The process is easy to operate and control parameter, has high salt reclaiming rate and high product quality, reaches the aim that the wastewater can be fully treated and has no production of three wastes, and has good economic and social benefits.

Description

technical field [0001] The invention relates to a process for recovering inorganic salts from desulfurization and decyanation wastewater, and specifically provides a method for recovering NH from wastewater produced by liquid-phase catalytic oxidation desulfurization and decyanation processes using ammonia as an alkali source. 4 CNS, (NH 4 ) 2 S 2 o 3 and (NH 4 ) 2 SO 4 and other inorganic salt processes, which belong to the wastewater treatment technology in the field of coal coking. Background technique [0002] H in coke oven gas 2 S and HCN are highly corrosive and toxic. During the subsequent processing of coal gas as synthesis gas, they will not only be highly corrosive to production equipment and pipelines, but will also poison and deactivate the catalyst, seriously affecting the final product. The yield and quality; when coal gas is used as industrial and civil fuel, the sulfur and nitrogen compounds contained in the waste gas generated by combustion will ser...

Claims

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Application Information

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IPC IPC(8): C01C3/20C01C1/24C01B17/64
Inventor 袁桂梅刘红伟谷文彬刁兴伟秦庆平杨树林
Owner JINNENG SCI & TECH
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