Low-sulfur emission sulfur recovery process for acid gas with intermediate concentration

Abstract

The invention provides a low-sulfur discharging and sulfur recycling process of intermediate concentration acid gas. A purpose of desulphurizing low-concentration acid gas with H2S content of 5 to 20 percent can be achieved by treating the low-sulfur acid gas by virtue of a direct oxidation reactor, a selective oxidation reactor and two adsorption desulphurization towers which can be connected in series and parallel; the direct oxidation reactor is filled with a TiO2 sulfur recycling catalyst, the selective oxidation reactor is filled with a H2S selective oxidation catalyst, catalysts in the direct oxidation reactor and selective oxidation reactor are packed in multiple layers, an air inlet and a cooling coil pipe are respectively arranged between two layers, and the adsorption desulphurization tower is filled with a thermally-renewable catalytic oxidation adsorption desulphurization agent; by selecting the appropriate catalyst and desulphurization agent and precisely controlling the process condition of each step, the total sulfur contained in the process discharged gas is that SO2 content is less than or equal to 10mg / m<3>. By virtue of thermal regeneration, the service life of the catalytic oxidation adsorption desulphurization agent is greatly prolonged, and the desulphurization amount of the catalytic oxidation adsorption desulphurization agent is greatly increased. The process has the advantages of low sulfur emission, high sulfur recycling rate (approximate to 100 percent), long service life and large desulphurization amount of the desulphurization agent, fewer replacement times, less expense, good desulphurization agent removal and scrapping condition, safety and the like.

Description

technical field [0001] The invention relates to a sulfur recovery process, in particular to a low-sulfur discharge sulfur recovery process for intermediate-concentration acid gas. Background technique [0002] During petrochemical, coal chemical, and coal gasification processes, part of the sulfur contained in raw materials is usually converted into H 2 S, separated to form H 2 The acid gas of S, the acid gas is generally processed through the sulfur recovery process, and the H 2 S is converted to elemental sulfur as much as possible. [0003] In the operation process of the sulfur recovery process unit, there are also two problems of emptying tail gas and solid waste. The tail gas evacuated through the chimney, of which, SO 2 Concentration is a continuous monitoring item, although the upper limit of the current air pollutant comprehensive emission standard GB16297-1996 is 700mg / m 3 It is not difficult to achieve, but there may be more stringent emission standards in th...

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Problems solved by technology

[0010] However, in practice, limited by the catalyst reaction performance and process control level, although the exhaust gas of this process can reach GB16297-1996 for SO 2 Concentration upper limit requirements, GB14554-93 for H 2 S concentration upper limit and emission requirements, but may not be able to meet the current stricter emission standards of the industry or region, such as achieving the total sulfur conversion of the exhaust tail gas to SO 2 ≤10mg / m 3 The main reason is that the structural design of direct oxidation reactor, selective oxidation reactor and catalytic oxidation adsorption desulfurization tower, the performance of catalyst and desulfurizer, and the control of process conditions need to be improved.

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