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Nitric acid two-step bleaching technology and device

A process, the technology of nitric acid, applied in the field of nitric acid production and preparation, can solve the problems of consuming a large amount of electric energy or heat energy, taking a long time, and not being able to solve dilute nitric acid, etc., and achieve the effect of rapid response

Active Publication Date: 2015-10-21
ANHUI HUAIHUA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The concentration of nitric acid produced by the above device may not be able to meet the needs of customers. Customers still need to prepare nitric acid aqueous solutions of different concentrations by themselves. However, in the process of preparing nitric acid aqueous solution, the mixture of concentrated nitric acid and dilute nitric acid will generate heat, which will cause a small amount of nitric acid to decompose. Its reaction formula is 4HNO 3 ==2H 2 O +4NO 2 +O 2 , so that the dilute nitric acid solution turns red, even if the colorless dilute nitric acid decomposes NO in a small amount during transportation 2 ,polluted environment
[0005] Conventional dilute nitric acid bleaching often utilizes air or steam, namely "cold bleaching" or "hot bleaching". NO produced during storage and transportation 2

Method used

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  • Nitric acid two-step bleaching technology and device

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Comparison scheme
Effect test

Embodiment 1

[0032] Such as figure 1 As shown, a device for the bleaching process in the preparation process of nitric acid includes an acid distribution tank 1, the top outlet of the acid distribution tank 1 is connected to a negative pressure pump 3, and the inlet end of the acid distribution tank 1 is connected to a hydrogen peroxide storage tank 4 respectively. 1. The outlet end of the urea solution storage tank 5 is connected, the top inlets of the hydrogen peroxide storage tank 4 and the urea solution storage tank 5 are all connected with the compressed air pipe 7, and the inside of the acid distribution tank 1 is horizontally provided with a gas distributor 2. Regulating valves 6 are provided at the inlet and outlet ends of the hydrogen peroxide storage tank 4 and the urea solution storage tank 5 .

[0033] That is, first open the regulating valve 6 on the inlet and outlet ends of the hydrogen peroxide storage tank 4, the hydrogen peroxide in the hydrogen peroxide storage tank 6 is ...

Embodiment 2

[0035] A kind of bleaching process in the preparation process of nitric acid, comprises the following steps:

[0036] (1) Pump the acid tank for preparing nitric acid to a slight negative pressure of -10Pa;

[0037] (2) With compressed air as the power, hydrogen peroxide is introduced into the nitric acid solution in the acid distribution tank, and the hydrogen peroxide enters the nitric acid solution evenly through the gas distributor and stirred evenly, so that the hydrogen peroxide and the NO in the acid distribution tank 2 The molar ratio is 1.5:2;

[0038] (3) Recover excess NO at the outlet of the acid distribution tank 2 ;

[0039] (4) Evenly add urea solution with a concentration of 32.5% into the acid mixing tank, the mass of urea in the urea solution accounts for 1 / 10,000 of the total mass of nitric acid in the acid mixing tank.

Embodiment 3

[0041] A kind of bleaching process in the preparation process of nitric acid, comprises the following steps:

[0042] (1) Pump the acid tank for preparing nitric acid to a slight negative pressure of -5Pa;

[0043](2) With compressed air as the power, hydrogen peroxide is introduced into the nitric acid solution in the acid distribution tank, and the hydrogen peroxide enters the nitric acid solution evenly through the gas distributor and stirred evenly, so that the hydrogen peroxide and the NO in the acid distribution tank 2 The molar ratio is 1.2:2;

[0044] (3) Recover excess NO at the outlet of the acid distribution tank 2 ;

[0045] (4) Evenly add urea solution with a concentration of 32.5% into the acid mixing tank, the mass of urea in the urea solution accounts for 1 / 10,000 of the total mass of nitric acid in the acid mixing tank.

[0046] In the present invention, hydrogen peroxide and urea are used to uniformly enter the solution in the acid distribution tank throug...

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Abstract

The invention provides a nitric acid two-step bleaching technology and device. According to the adopted technical scheme, the technology comprises the steps that 1, a nitric acid preparation groove for nitric acid preparation is vacuumized to micro-negative pressure; 2, hydrogen peroxide is added into a nitric acid solution in the nitric acid preparation groove, and the mixture is evenly stirred; 3, redundant NO2 is recycled at the outlet end of the nitric acid preparation groove; 4, a urea solution is evenly added into the nitric acid preparation groove. Compressed air is used as power, the hydrogen peroxide and the urea solution pass through a gas distributor 20 cm away from the bottom of the nitric acid preparation groove and then evenly enter the nitric acid preparation groove, the hydrogen peroxide reacts with NO2 in nitric acid at first to be converted into nitric acid, meanwhile, NO2 in nitric acid escapes out thoroughly to enter a negative pressure device, and concentrated nitric acid is bleached; then a small amount of or subsequently-produced NO2 reacts with a subsequently-added urea solution, so that the nitric acid solution has no color for a long time, the content of NO2 in the nitric acid solution is rapidly controlled, and the problem that NO2 content exceed standards is solved.

Description

technical field [0001] The invention relates to the technical field of production and preparation of nitric acid, in particular to a two-step nitric acid bleaching process and a device thereof. Background technique [0002] Nitric acid is one of the most important chemical products. Nitric acid is mainly produced by ammonia oxidation in industry, and is used to make fertilizers, explosives, nitrates, etc. Pure nitric acid is a colorless transparent liquid, and industrial nitric acid solution is brown due to dissolved nitrogen dioxide. [0003] At present, nitric acid is used in all walks of life, but different industries have different requirements on the concentration of nitric acid. For example, the production of ammonium nitrate by neutralization requires nitric acid with a concentration of 37-43% as a raw material, while the production of ammonium nitrate by pressurization requires a concentration of 60%. Nitric acid is used as raw material; the IT industry needs nitr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B21/46
Inventor 孙虎
Owner ANHUI HUAIHUA
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