Apparatus used for preparing aqueous nitric acid solution

Abstract

The invention relates to an apparatus used for preparing aqueous nitric acid solution. The apparatus comprises an acid preparation tank, an acid cooler, and acid circulating tank and an ejector; the acid preparation tank is provided with a gas outlet, a decolorizing agent charging door, a dilute acid charging door, a dense acid charging door, a recycle acid outlet and a recycle acid inlet; a cooled medium inlet of the acid cooler and the recycle acid outlet of the acid preparation tank are communicated by a circulating pump; a cooled medium inlet of the acid cooler is communicated with the recycle acid inlet of the acid preparation tank; the gas outlet of the acid preparation tank is communicated with an extracted medium inlet of the ejector; an outlet of the ejector is communicated with the acid circulating tank; an outlet of the acid circulating tank is communicated with an medium inlet of the ejector by a negative pressure pump. The apparatus is capable of preparing nitric acid products with qualified quality and appearance, and is convenient for maintenance; by-product acid mist is less; safety and environment protection property are excellent; the decolorizing agent is added directly for decoloration, decoloration effects are excellent, and decoloration is easy to control; and production cost of the whole apparatus is low.

Description

technical field [0001] The invention relates to a device for preparing nitric acid aqueous solution. Background technique [0002] Nitric acid (molecular formula: HNO 3 ) is a strong acid. Pure nitric acid is a colorless liquid with a boiling point of 83°C. It condenses into colorless crystals at -42°C. It is miscible with water and has strong oxidizing and corrosive properties. Depending on the mass fraction of nitric acid in the aqueous solution, It can be divided into 98 acid, 97 acid, 68 acid, 62 acid, 50 acid, 40 acid, etc. It is widely used in manufacturing, coating, medicine, printing and dyeing, rubber, plastic, metallurgy, national defense and other industries. [0003] At present, most enterprises use 98% concentrated nitric acid mixed with water to produce different concentrations of nitric acid. Simply mix water and 98% nitric acid in proportion. The disadvantages are: the 98 acid dilution process is an exothermic reaction, the acid temperature rises very quic...

AI Technical Summary

Problems solved by technology

The disadvantages are: the 98 acid dilution process is an exothermic reaction, the acid temperature rises very quickly, a large amount of heat is released, accompanied by a large amount of acid mist and it is difficult to recycle, the environment is polluted, and the finished acid is caused by NO 2 High content is reddish brown, resulting in substandard appearance

[0004] Chinese patent CN102580591 "A device for preparing nitric acid aqueous solution" discloses a production device for preparing nitric acid with different concentrations, which solves the problem of acid mist polluting the environment during the preparation process to a certain extent. In the body, if the cooler breaks down and needs to be maintained, it is not only necessary to discharge the nitric acid aqueous solution in the acid preparation tank, but also to enter the tank for maintenance, which has the problem of inconvenient maintenance. In addition, the feeding position of the nitric acid production equipment is set At the top of the tank, the mixing is not sufficient, and the exothermic reaction occurs during the falling process of the material, and the reaction range in the entire tank is large.

In addition, the mixture of concentrated nitric acid and water has the largest heat release, and the resulting reddish-brown nitrogen dioxide gas has a high content. Although the acid distribution tank is equipped with a tail gas recovery device to quickly remove the nitrogen oxide gas, the nitrogen oxide gas will still be released during the cooling process. Partially blended into nitric acid, resulting in finished acid due to NO 2 High content is reddish brown, resulting in substandard appearance

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