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Nitrification waste acid recovery process of insoluble organic matters

A technology for nitrating waste acid and organic matter, applied in the preparation of organic compounds, organic chemistry, nitric acid, etc., can solve the problems of increased energy consumption, increased waste acid water content, and increased equipment size in the concentration stage, reducing energy consumption and reducing equipment size. Small size, the effect of reducing equipment investment

Active Publication Date: 2022-07-08
天津大学浙江绍兴研究院
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] There are two main problems in the recovery process of nitric acid waste acid in the above-mentioned prior art: one is that when the waste acid is purified by steam stripping, the water content in the waste acid increases, which leads to an increase in energy consumption in the concentration stage; Under certain conditions, the equipment size increases, which brings about an increase in equipment investment

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  • Nitrification waste acid recovery process of insoluble organic matters

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Effect test

Embodiment 1

[0039] The total amount of a nitrification waste acid is 1500kg / h, which is composed of water, H 2 SO 4 , HNO 3 , organic matter, the mass fractions are 16%, 80%, 3%, 1% respectively, and the organic matter is nitrobenzene.

[0040] The temperature of the waste acid reaches 60℃ after passing through the waste acid preheater, and then enters the organic phase separator. The phase separator adopts a single-stage gravity separation type phase separator, and the residence time of the waste acid in the phase separator is 1.5h. After passing through the phase separator, the organic matter content in the waste acid is reduced to 180 ppm, which can avoid the coking of organic matter in the equipment in the subsequent process.

[0041] The purified waste acid enters the nitric acid recovery tower from the waste acid transfer tank. The operating pressure of the denitrification tower is 20 kPa, the heating temperature at the bottom of the tower is 160 °C, and the main component of the ...

Embodiment 2

[0045] The total amount of waste acid is 1500kg / h, composed of water, H 2 SO 4 , HNO 3 , organic matter, the mass fractions are 16%, 80%, 3%, 1% respectively, and the organic matter is nitrobenzene.

[0046] The temperature of the waste acid reaches 70 °C after passing through the waste acid preheater, and then enters the organic phase separator. The phase separator adopts two stages of cyclone separation and gravity separation. The residence time of waste acid in the phase separator is 2.5 h. The organic content of the spent acid was reduced to 350 ppm after passing through the phase separator. The waste acid after removing the organic matter passes through the nitric acid recovery tower and the sulfuric acid concentration tower.

[0047] The operating pressure of the nitric acid recovery tower is 15 kPa, the temperature at the bottom of the tower is 140 °C, and the nitric acid vapor is obtained at the top of the tower, containing HNO. 3 , a small amount of organic matte...

Embodiment 3

[0052] The total amount of nitrification waste acid is 1000kg / h, which is composed of water, H 2 SO 4 , HNO 3 , organic matter, the mass fractions are 29%, 65%, 5%, 1% respectively, and the organic matter is fluoronitrobenzene.

[0053] The temperature of the waste acid reaches 50℃ after passing through the waste acid preheater, and then enters the organic phase separator. The phase separator adopts the centrifugal separation type and the gravity separation type phase separator. The waste acid stays in the phase separator for 4 h. After passing through the phase separator, the organic matter content in the waste acid is reduced to 140 ppm, which can avoid the coking of organic matter in the equipment in the subsequent process.

[0054] The purified waste acid enters the nitric acid recovery tower from the waste acid transfer tank. The nitric acid recovery tower is operated at atmospheric pressure, the heating temperature at the bottom of the tower is 150 °C, and the top of ...

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Abstract

The invention discloses a process for recovering nitration waste acid containing insoluble organic matters, which belongs to the technical field of industrial waste acid treatment and mainly comprises three steps of organic matter separation, nitric acid recovery and sulfuric acid concentration. In the organic separation step, organic matters in the waste acid are separated and removed through an organic matter phase separator; in the nitric acid recovery step, nitric acid in the waste acid is recovered by adopting a rectification separation method; in the step of concentrated sulfuric acid, dilute sulfuric acid is concentrated by adopting a quartz concentration tower, and concentrated sulfuric acid with the concentration of 98% is obtained under the normal-pressure operation condition. According to the nitration waste acid recovery process provided by the invention, organic matters are separated through the organic matter phase separator, and the amount of water needing to be evaporated in a sulfuric acid concentration stage is reduced, so that the process operation energy consumption is reduced; the dilute sulfuric acid concentration process can be carried out under the normal pressure condition, so that compared with the existing negative pressure concentration, the tower equipment size is smaller, and the equipment investment is reduced.

Description

technical field [0001] The invention relates to the technical field of industrial waste acid treatment, in particular to a process for recovering nitrification waste acid of insoluble organic matter. Background technique [0002] The nitration reaction is widely used in the production of chemical intermediates and products such as medicines, pesticides, and dyes. The commonly used nitration methods include nitric acid-sulfuric acid mixed acid nitration. In the mixed acid nitration process, the amount of sulfuric acid is relatively high, while the amount of nitric acid is close to the theoretical value. Meanwhile, in general, the nitration product is liquid at the reaction temperature, and insoluble in waste sulfuric acid, such as nitrobenzene, fluoronitrobenzene, and difluoronitrobenzene. After the mixed acid nitration reaction is completed, the nitrification product is extracted by layering, and a large amount of nitrification waste acid is produced. The main components o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B21/46C01B17/94C01B17/88C07C201/16C07C205/06C07C205/12
CPCC01B21/46C01B17/94C01B17/88C07C201/16C07C205/06C07C205/12Y02A40/20
Inventor 李建昌訾灿梁晓锋刘华杰刘涛党修湖张敏卿
Owner 天津大学浙江绍兴研究院