A system for producing liquid SO2 from concentrated waste acid

Abstract

The invention relates to a system for preparing liquid SO2 from concentrated waste acid, belonging to the fields of waste acid treatment and liquid SO2 production. Sulfur is used as a reducer to reduce the concentrated waste acid to prepare SO2 gas, and the unreacted high-solid-content waste acid is gasified and decomposed in an inert atmosphere, thereby recovering the sulfur element in the waste acid and separating the solid-phase slag in the waste acid; and the prepared concentrated SO2 gas is dehydrated and dried, and is subjected to pressure cooling separation to obtain the liquid SO2. The system for preparing liquid SO2 from concentrated waste acid comprises a temperature-control gasification and decomposition system, an oxidation-reduction reaction system, a heat recovery system, a sulfur melting system, a dehydration and drying system and a compression separation system. By adding the sulfur to initiate the oxidation-reduction reaction, the amount of waste acid entering the gasification chamber is greatly lowered, thereby effectively lowering the heat consumption of gasification; the SO2 yield is greatly enhanced, and the SO2 concentration is high; the energy source is sufficiently recovered, so the energy consumption is low; and the system has the advantages of small pollution and no waste gas emission.

Description

technical field [0001] The invention belongs to the field of waste acid treatment and liquid SO 2 production area. The invention relates to a method for producing liquid SO from concentrated waste acid 2 system. Furthermore, sulfur is used as a reducing agent to reduce concentrated waste acid to produce SO 2 Gas, the unreacted waste acid with high solid content is further sent to gasification and decomposition in an inert atmosphere, the sulfur element in the waste acid is recovered, and the solid phase slag in the waste acid is separated; the prepared concentrated SO 2 The gas is dried by dehydration, pressurized and cooled to obtain liquid SO 2 . Background technique [0002] Some industrial production uses sulfuric acid to produce concentrated waste acid, such as the acid used for drying mixed gas and the acid used for acetylene cleaning in PVC production by calcium carbide method, both of which produce high-concentration black waste sulfuric acid (concentration is 7...

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Problems solved by technology

[0005] This patent has solved the reclaiming problem of single 85~90% alkylation waste sulfuric acid well, but there are following problems in this process: (1) waste acid pyrolysis furnace directly sprays acid gasification to easily make combustion gas unstable, not Complete; (2) The high-temperature cracked gas passes through the waste heat boiler, and the temperature drops to 350°C, which may easily cause local acid gas condensation and corrode the waste heat boiler; (3) After the waste heat boiler recovers heat, it directly uses dilute acid to wash and cool down, which cannot be fully utilized. Part of the heat energy will also increase the amount of waste dilute acid; (4) After washing with dilute acid, it will be further cooled with an intercooler. The intercooler equipment is large and the heat transfer efficiency is low

However, the waste acid is still fully gasified, and the heat of gasification is relatively large, so there is still room for improvement in energy consumption.

[0008] Liquid SO 2 Has a wide range of applications, the preparation of liquid SO 2 Concentrated SO 2 The gas source generally adopts the method of absorption concentration and regeneration concentration, which consumes a lot of energy

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