Nitrosyl sulfuric acid production method and system

Abstract

The invention discloses a green continuous production method of nitrosyl sulfuric acid. The production method includes the steps: (1) condensing waste acid to obtain condensed waste acid; (2) continuously leading the condensed waste acid in an absorption tower to absorb mixed tail gas generated in the production of the nitrosyl sulfuric acid to obtain absorbed sulfuric acid; (3) preparing the absorbed sulfuric acid and water and / or concentrated sulfuric acid into sulfuric acid solution with demand concentration, and mixing the sulfuric acid solution and the concentrated sulfuric acid into mixed acid; (4) continuously feeding the mixed acid and gas with sulfur dioxide into a reaction tower to perform reaction to obtain a nitrosyl sulfuric acid finished product. The invention further discloses a production system of the nitrosyl sulfuric acid. The tail gas generated in the production process of the nitrosyl sulfuric acid is absorbed and recycled by the aid of the condensed waste acid, the mixed acid is preheated by the nitrosyl sulfuric acid finished product, and the nitrosyl sulfuric acid is synthesized in a continuous and automatic chain control manner. According to automatic chaincontrol, heat exchange and tail gas resource utilization, emission reduction of tail gas is achieved, energy is saved, consumption is reduced, and yield is improved.

Description

technical field [0001] The invention relates to the field of dye intermediate production, in particular to a green production method and system for dye intermediate nitrosyl sulfuric acid. Background technique [0002] Nitrosyl sulfuric acid is an important diazotization raw material. Compared with sodium nitrite, it has higher activity and can carry out diazotization reaction with some low activity amino groups. And no salt will be generated during the diazotization process, which is convenient for subsequent processing. [0003] Because nitrosyl sulfuric acid is easy to decompose, concentrated sulfuric acid is used as a solvent for storage and transportation in industry (some production processes also directly use sulfuric acid as a raw material to participate in the reaction). Since the reaction raw materials have volatile components and gaseous components, they will produce waste gases such as nitric acid mist, nitrogen oxides, sulfur dioxide, and sulfur trioxide durin...

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Problems solved by technology

[0004] The Chinese patent literature with the publication number CN106379875A discloses a production method and application of nitrosyl sulfuric acid. The patent first uses mixed acid to absorb tail gas, but due to the high content of volatile nitric acid and nitrogen oxides in the mixed acid, the absorption of tail gas At the same time, there will be new tail gas, which needs to be absorbed by sodium hydroxide aqueous solution. After the absorption, acid and alkali adjustment and evaporation crystallization are required. Although the resource-based products of sodium nitrate and sodium chloride are obtained, the process is cumbersome and consumes more energy. high

[0005] Nitric acid mist, sulfur dioxide, sulfur trioxide, water, nitrogen oxides and other exhaust gases are produced during the production of nitrosyl sulfuric acid. Mixed acid is generally used for pre-absorption in the treatment of these exhaust gases. Strong, so the absorption of exhaust gas is not complete, and the follow-up exhaust gas still needs other treatment methods, which will increase energy consumption and emissions

And the reaction raw materials lost in the tail gas will cause the loss of products

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