A raw material gas purification system for producing sulfuric acid from concentrated waste acid

Abstract

The invention relates to a system for producing sulphuric acid purified feed gas from concentrated waste acid, belonging to the field of treatment of waste acid and production of sulphuric acid; sulphuric acid purified feed gas is produced by carrying out part oxidation-reduction reaction by taking sulphur as the reducing agent and concentrated waste acid as the oxidizing agent; unreacted waste acid with high solid content is further gasified and decomposed; elemental sulphur in waste acid is recycled; solid residues in waste acid are separated; and the system disclosed by the invention comprises a process of controlling temperature to gasify and decompose, a process of carrying out oxidation-reduction reaction, a process of recycling thermal energy and a process of dissolving sulphur. The system for producing sulphuric acid purified feed gas from concentrated waste acid disclosed by the invention has the beneficial effects that oxidation-reduction reaction is carried out by adding sulphur; the amount of waste acid entering a gasification chamber is greatly reduced; consumption of gasification thermal energy is effectively reduced; the yield of sulphuric acid feed gas is greatly increased; the gasification temperature of controlled-temperature gasification is lower than that of high-temperature gasification; the energy consumption is low; energy is sufficiently recycled; waste solids are discharged in the form of dry solid residues, and therefore, pollution is reduced.

Description

technical field [0001] The invention belongs to the fields of waste acid liquid treatment and sulfuric acid production. The invention relates to a raw material gas purification system for producing sulfuric acid from concentrated waste acid. 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 70% to 95%), and its appearance is black and sticky. Complex and difficult to recycle, causing great pressure on ecological protection. [0003] Related patents on concentrated waste acid include: [0004] CN1751984 discloses a waste sulfuric acid high-temperature cracking, adiabatic humidification pickling purification, two-transfer and two-suction process, that is, the alkylation waste sulfuric acid is produced by...

AI Technical Summary

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.

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