Ammonia regeneration and recycling process for ammonia desulfurization

An ammonia-based desulfurization and process technology, applied in the field of ammonia-based desulfurization, can solve problems such as unorganized emission of environmental pollution, poisoning of operators around the regeneration pool, etc., and achieve the effect of avoiding major poisoning

Pending Publication Date: 2019-04-05
张君宇
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0014] The main defect of this process is: after the desulfurization slurry flows out of the desulfurization tower, the lime is impacted in the lime digestion tank, and then fully stirred in the regeneration tank to completely react to generate calcium sulfite and ammonia water; at the same time, aeration and oxidation are carried out in the regeneration tank to make Oxidation of calcium sulfite to gypsum
At the same time, large-scale ammonia stripping will cause serious fugitive emission environmental pollution, as well as the poisoning risk of operators around the regeneration pool

Method used

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  • Ammonia regeneration and recycling process for ammonia desulfurization

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Embodiment 1

[0057] The ammonia regeneration and recycling process of ammonia desulfurization includes the following process steps:

[0058] (1) Part of the desulfurization liquid containing ammonium sulfite and ammonium bisulfite undergoes redox reaction after aeration:

[0059] 2(NH 4 ) 2 SO 3 +O 2 →2(NH 4 ) 2 SO 4 , 2NH 4 HSO 3 +O 2 →2NH 4 HSO 4 ;

[0060] (2) The oxidized desulfurization liquid and milk of lime undergo a displacement reaction under stirring:

[0061] (NH 4 ) 2 SO 4 +Ca(OH) 2 →2NH 3 + CaSO 4 2H 2 O.

[0062] 2NH 4 HSO 4 +Ca(OH) 2 →(NH 4 ) 2 SO 4 +CaSO 4 2H 2 O;

[0063] (3) Calcium sulfate dihydrate is separated to obtain regenerated ammonia solution after flocculation and precipitation;

[0064] (4) The regenerated ammonia solution is mixed with another part of the desulfurization liquid containing ammonium sulfite and ammonium bisulfite:

[0065] NH 3 + NH 4 HSO 3 →(NH 4 ) 2 SO 3 ;

[0066] (5) The desulfurization liquid is mixed ...

Embodiment 2

[0074] The difference between embodiment 2 and embodiment 1 is that the control conditions of each process step are different. Specifically, in step (1), the oxidation rate of ammonium sulfite and ammonium bisulfite is not lower than 98%, and the aeration oxygen-sulfur molar ratio is not lower than 1.5. In step (2), the pH value of the replacement reaction system is controlled to be kept at 6.8. In steps (4) and (5), the regenerated desulfurization liquid 6.2 is controlled by controlling the amount of regenerated ammonia water and additional ammonium bicarbonate aqueous solution. In step (6), the pH value of the desulfurization slurry after the desulfurization reaction is maintained at 6.2 by controlling the amount of regenerated ammonia water and supplementary ammonium bicarbonate aqueous solution. In step (2), the weight percent concentration of milk of lime is 10%. In step (2), the stirring speed of the reaction system is not lower than 70 rpm. In step (3), polyacrylamid...

Embodiment 3

[0076] The difference between embodiment 3 and embodiment 1 is that the control conditions of each process step are different. Specifically, in step (1), the oxidation rate of ammonium sulfite and ammonium bisulfite is not lower than 98%, and the aeration oxygen-sulfur molar ratio is not lower than 1.5. In step (2), the pH value of the replacement reaction system is controlled to remain at 6.9. In steps (4) and (5), the regenerated desulfurization liquid 5.8 is controlled by controlling the amount of regenerated ammonia water and supplemented ammonium bicarbonate aqueous solution. In step (6), the pH value of the desulfurized slurry after the desulfurization reaction is maintained at 4.5 by controlling the amount of regenerated ammonia water and supplementary ammonium bicarbonate aqueous solution. In step (2), the weight percent concentration of milk of lime is 30%. In step (2), the stirring speed of the reaction system is not lower than 70 rpm. In step (3), polyacrylamide ...

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Abstract

The invention relates to an ammonia regeneration and recycling process for ammonia desulfurization. The ammonia regeneration and recycling process comprises the following steps: (1) a part of desulfurization solution containing ammonium sulfite and ammonium bisulfite has oxidation-reduction reaction by virtue of aeration; (2) the oxidized desulfurization solution and lime milk are stirred to ha replacement reaction; (3) calcium sulfate dihydrate is flocculated, precipitated and separated to obtain a regenerated ammonia solution; (4) the regenerated ammonia solution is mixed with another part of desulfurization solution containing ammonium sulfite and ammonium bisulfite; (5) the desulfurization solution is mixed and supplemented with ammonium bicarbonate aqueous solution to form aregenerated desulfurization solution; and (6) the regenerated desulfurization solution is used for desulfurizing flue gas. According to the ammonia regeneration and recycling process for ammonia desulfurizationof the invention, the process of 'regenerating ammonia gas first and then performing the aeration oxidation' in the prior art is replaced by the process of 'first performing the aeration oxidation and then regenerating the ammonia gas', thereby successfully avoiding major toxicity and unorganized emission hazards caused by large-scale blowing off of ammonia gas under aeration conditions, as wellas large-scale loss of the desulfurization agent in the added materials.

Description

technical field [0001] The invention relates to the technical field of ammonia desulfurization, in particular to a desulfurization process applied to flue gas emission in small and medium-sized enterprises, more specifically, it relates to an ammonia regeneration recycling process for ammonia desulfurization. Background technique [0002] Ammonia desulfurization is a relatively mature desulfurization process, which has a high desulfurization efficiency (usually up to 98% (SO2) removal rate), a small spray cycle water-gas ratio, and has the ability to remove stocks. Investment savings, lower equipment operating costs. On January 15, 2018, the Ministry of Environmental Protection issued the "General Technical Specifications for Ammonia Flue Gas Desulfurization Engineering HJ2001-2008", so that enterprises can promote ammonia desulfurization with laws to follow. [0003] The final by-products of ammonia desulfurization are varied. The by-product is ammonium sulfate, HJ2001-20...

Claims

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Application Information

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IPC IPC(8): B01D53/50B01D53/96B01D53/78
CPCB01D53/502B01D53/96B01D2251/2062
Inventor 张君宇
Owner 张君宇
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