Low sulfur emission sulphur recovery process

Abstract

The present invention provides a low sulfur emission sulphur recovery process, which comprises a burning furnace, a first stage Claus reactor, a second stage Claus reactor, a selective hydrogenation reduction reactor, a selective oxidation reactor, and two adsorption desulfurization towers capable of being connected in a series parallel connection manner, wherein the burning furnace, the first stage Claus reactor and the second stage Claus reactor are sequentially connected in series. According to the present invention, with the appropriate selection of each catalyst, the appropriate selection of the desulfurization agent, and the accurate control of each step process condition, the total standard sulfur in the process emission gas is that SO2 is less than or equal to 10 mg/m<3>; and the low sulfur emission sulphur recovery process has advantages of low sulfur emission, long desulfurization agent service life, high desulfurization capacity, less replacement frequency, low cost and the like.

Description

technical field [0001] The invention relates to a sulfur recovery process, in particular to a low sulfur emission sulfur recovery process. 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 Acid gas with high S content, the acid gas is generally treated by sulfur recovery process, H 2 S is converted to elemental sulfur as much as possible. certain high H 2 During the purification process of natural gas with S content, the separation of H 2 The acid gas formed by S should also be converted into elemental sulfur as much as possible through the sulfur recovery process. [0003] In the operation process of the sulfur recovery 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...

AI Technical Summary

Problems solved by technology

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 the industry or region; H 2 S is one of the odor pollutants included in the odor pollutant discharge standard GB14554-93. The emission limit is more stringent, and the upper limit of the factory boundary standard is 0.45 / 0.80mg / m for the third grade. 3 , the upper limit of 100m chimney emission is 14kg / h

[0004] Chinese patent 200910018803.9 discloses a catalyst combination process for a sulfur recovery unit, including sequentially serially connected combustion furnaces, primary Claus reactors, secondary Claus reactors, selective hydrogenation reduction reactors, selective oxidation Reactor and two parallel catalytic oxidation adsorption desulfurization towers; the upper part of the first-stage Claus reactor is filled with deoxidation protection type sulfur recovery catalyst, and the lower part is filled with TiO 2 Sulfur recovery catalyst, secondary Claus reactor filling aid type sulfur recovery catalyst, most of SO 2 、H 2 S reaction is converted into elemental sulfur; the selective hydrogenation reduction reactor is filled with SO 2 Selective reduction catalyst, the remaining small amount of SO 2 Selective reduction to elemental sulfur; selective oxidation reactor filled with H 2 S selective oxidation catalyst, the remaining H 2 Most of S is selectively oxidized to elemental sulfur; the catalytic oxidation adsorption desulfurization tower is filled with H 2 S catalytically oxidizes and adsorbs the desulfurizer, and the residual H 2 S is catalytically oxidized to elemental sulfur, so that the desulfurized tail gas meets the national emission requirements of GB16297-1996, but this process does not involve and provide a technical solution for low-sulfur emissions, and does not give full play to the desulfurization accuracy of the catalytic oxidation adsorption desulfurizer

If the catalytic oxidation adsorption desulfurization tower inlet gas SO 2 / H 2 The concentration ratio of S is higher than the 1:2 required to generate elemental sulfur, and the SO in the outlet gas of the desulfurization tower 2 The concentration may be higher than 10mg / m 3 , this point at the selective oxidation reactor inlet O 2 It is easy to occur when the content is too high and the temperature is too high, because SO 2 is H 2 The S selective oxidation reaction generates a side reaction product of elemental sulfur; or the temperature of the inlet gas of the selective hydrogenation reduction reactor is not high enough, H 2 Insufficient amount, resulting in SO 2 Can't restore it all, this part of SO 2 It will also enter the catalytic oxidation adsorption desulfurization tower, and cannot be completely removed in the catalytic oxidation adsorption desulfurization tower, which may cause SO in the outlet gas of the desulfurization tower, that is, the process tail gas. 2 The content is much higher than 10mg / m 3

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