Method and device for recovering ammonia from nitrochlorobenzene ammonolysis wastewater

A technology of nitrochloroaniline and a recovery method is applied in the field of wastewater treatment, can solve problems such as large consumption, and achieve the effects of lightening the load, reducing the amount of wastewater, and reducing the amount of acid used

Inactive Publication Date: 2013-10-23
杜惠红
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, before entering the electrolytic catalytic oxidation device, the wastewater must be weakly acidic, and the ammonium hydrolysis wastewater contains excess free ammonia, which forms a buffer system with ammonium chloride, so it takes a lot of acid to neutralize it into weak acidity

Method used

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  • Method and device for recovering ammonia from nitrochlorobenzene ammonolysis wastewater
  • Method and device for recovering ammonia from nitrochlorobenzene ammonolysis wastewater

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Experimental program
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Effect test

Embodiment 1

[0017] Embodiment 1 of the present invention: when it is necessary to improve the recovery ratio of ammonia, the recovery method of ammonia in nitrochlorophenyl ammonolysis wastewater: add sodium hydroxide to the waste water produced after the ammonolysis of nitrochlorophenyl to make the ammonium therein The ions are converted into free ammonia, sent to the vacuum evaporator, the waste water is heated to boiling, and the boiling time is maintained for 8 to 10 hours, so that the free ammonia in it escapes; the free ammonia in the steam is absorbed by water and returned to the ingredients of nitrochlorophenyl ammonolysis process, recycled as ammonolysis raw material. After this treatment, the ammonia nitrogen index of the wastewater can be reduced to 100ppm.

[0018] The recovery device of ammonia in the nitrochlorobenzene ammonolysis waste water that above-mentioned method adopts: comprise reaction tank 2, ammonia distillation equipment 3 and water absorption tower 4, nitrochlo...

Embodiment 2

[0019] Embodiment 2 of the present invention: when it is necessary to improve the recovery ratio of ammonia, the recovery method of ammonia in the ammonolysis wastewater of nitrochlorophenyl: add calcium oxide or calcium hydroxide to the waste water produced after the ammonolysis of nitrochlorophenyl, so that The ammonium ions in it are converted into free ammonia, sent to the vacuum evaporator, the waste water is heated to boiling, and the boiling time is maintained for 6-8 hours, so that the free ammonia in it escapes; the free ammonia in the steam is absorbed by water and returned to nitrochloroaniline The batching process of ammonia solution is recycled as raw material for ammonia solution. After this treatment, the ammonia nitrogen index of the wastewater can be reduced to 400ppm.

[0020] The recovery device of ammonia in the nitrochlorobenzene ammonolysis waste water that this method adopts is the same as embodiment 1.

[0021] In the above embodiments, the conversion ...

Embodiment 3

[0022] Embodiment 3 of the present invention: when it is necessary to improve the recovery ratio of ammonium chloride, the recovery method of ammonia in the ammonium hydrolysis waste water of nitrochlorophenyl: the waste water produced after the ammonium hydrolysis of nitrochlorophenyl is directly sent into the ammonia distillation equipment, and the waste water is Heating to boiling, maintaining the boiling time for 4-5 hours, so that the free ammonia escapes; the free ammonia in the steam is absorbed by water and returned to the batching process of nitrochloroaniline ammonolysis, and recycled as raw material for ammonolysis. After this treatment, the ammonia nitrogen index of the wastewater can be reduced to 800ppm.

[0023] The recovery device of ammonia in the nitrochlorobenzene ammonolysis waste water that this method adopts: comprise ammonia distillation equipment 3 and water absorption tower 4, nitrochlorobenzene ammonolysis device 1 is connected with ammonia distillatio...

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Abstract

The invention discloses a method and device for recovering ammonia from nitrochlorobenzene ammonolysis wastewater. According to the method, ammonolysis wastewater is evaporated by using ammonia distilling equipment so as to liberate free ammonia; or an alkaline substance is added firstly so as to convert ammonium ions in the ammonolysis wastewater into the free ammonia, and then, evaporation is carried out; the free ammonia in vapor is absorbed by water, then returns to a material proportioning process of nitrochlorobenzene ammonolysis and is cyclically reused in a manner of serving as an ammonolysis raw material; and then, the treated wastewater is subjected to electrolysis and catalytic oxidation treatment and ammonium chloride recovery. Compared with the prior art, the method and the device have the advantages that the free ammonia is recovered and utilized in a cycling manner, so that the consumption of ammonia is reduced; after the free ammonia is recovered, the consumption of neutralizing acid is reduced, the volume of the wastewater is reduced, and the load of the sewage treatment device is reduced; and by adopting the method and the device, the recovery ratio of ammonia and ammonium chloride can be adjusted randomly according to the market price of liquid ammonia and ammonium chloride.

Description

technical field [0001] The invention relates to a method and a device for recovering ammonia in nitrochlorobenzene ammonolysis wastewater, belonging to the technical field of wastewater treatment. Background technique [0002] In the ammonolysis of nitrochloroaniline, due to the use of excess ammonia, ammonium chloride is generated after the reaction. Therefore, after centrifugation and washing, the wastewater contains relatively high concentrations of free ammonia and ammonium chloride, as well as a small amount of nitrochlorobenzene and nitroaniline. At present, the treatment method of ammonium nitrochlorobenzene wastewater is as follows: firstly use electrolytic catalytic oxidation sewage treatment device to degrade organic matter such as nitrochlorobenzene and nitroaniline; then use ammonium chloride recovery device to recover ammonium chloride. After being treated by this method, the ammonia nitrogen in the wastewater can reach the discharge standard. But before enter...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/20C02F1/04C02F1/58B01D53/18
Inventor 杜惠红
Owner 杜惠红
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