A kind of resource treatment method of waste acid solution in the production process of nitrobenzene

Abstract

The invention discloses a resourceful treatment method of a waste acid solution in the nitrobenzene production process. Firstly, the waste acid solution is added into an azeotropic rectifying tower to be subjected to azeotropic rectifying separation, nitric acid with the content being larger than or equal to 67 wt% is discharged from the top of the tower, sulfuric acid, with the content being larger than or equal to 64 wt%, discharged from the bottom of the tower is added into the azeotropic rectifying tower with nitrobenzene as an extraction agent, and sulfuric acid with the content larger than or equal to 95 wt% is discharged from the bottom of the azeotropic rectifying tower; nitrobenzene obtained from the top of the azeotropic rectifying tower and mixed steam of water are added into a liquid-liquid layering tank after condensation, water is obtained on the upper layer of the liquid-liquid layering tank, nitrobenzene is obtained on the lower layer of the liquid-liquid layering tank, and circulation use is achieved. The separation technology is simple and convenient and easy to implement, and the aims for treatment and circulation use of the waste acid solution are achieved.

Description

technical field [0001] The invention relates to a method for recycling waste acid, in particular to a method for recycling waste acid solution in the production process of nitrobenzene. Background technique [0002] In the production process of nitrobenzene, sulfuric acid is used as a catalyst for nitration reaction, and waste acid solution containing nitric acid and sulfuric acid is produced at the same time. If neutralization and then biochemical treatment are used, the treatment cost is high, secondary pollution is likely to occur, and further treatment is required. [0003] At present, domestic and foreign waste acid treatment, there are concentration method, pyrolysis method and absorption of SO 3 law etc. The concentration method adopts high-temperature evaporation heating dehydration to carbonize the organic matter and remove it by filtration, but the concentration of sulfuric acid obtained by this method is difficult to reach more than 90%; the high-temperature cra...

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Problems solved by technology

The concentration method adopts high-temperature evaporation heating dehydration to carbonize the organic matter and remove it by filtration, but the concentration of sulfuric acid obtained by this method is difficult to reach more than 90%; the high-temperature cracking method uses a high temperature of about 1000 ° C to decompose sulfuric acid into SO 2 Afterwards, it is used to prepare concentrated sulfuric acid, and the equipment investment and energy consumption of this method are relatively high; absorbing SO 3 French, SO 3 The source is inconvenient, and the production cost is also very high

[0004] In summary, although there are many ways to deal with waste acid, there are defects such as high cost and difficulty in obtaining more than 95% sulfuric acid in various methods.

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