Process for reducing sulfur emission of sulfur plant

摘要

The present invention provides a process for reducing sulfur emission of a sulfur plant, wherein the sulfur plant includes a thermal reaction unit, a catalytic reaction unit and a tail-gas purification unit, the process is characterized in that the waste-gas from the degassing of the liquid sulfur in the liquid sulfur tank is introduced into the catalytic reaction unit, and/or the waste-gas from the degassing of the liquid sulfur in the liquid sulfur tank is introduced into the tail-gas purification unit. In present invention, the H2S in purified tail-gas can be reduced to no more than 10 ppm(v) and the SO2 emission concentration of the sulfur plant can be reduced to no more than 100 mg/m3.

主权项

1. A process for reducing sulfur emission of a sulfur plant, comprising:
introducing a H2S-containing acid gas into a thermal reaction unit, combusting the H2S-containing acid gas to produce SO2, and conducting Claus reaction between H2S and SO2 to produce a first elemental sulfur stream and a process gas, wherein the first elemental sulfur stream is introduced into a liquid sulfur tank; introducing the process gas into a catalytic reaction unit to carry out Claus catalytic conversion to obtain a second elemental sulfur stream and a Claus tail gas, wherein the second elemental sulfur stream is introduced into the liquid sulfur tank; and introducing the Claus tail gas into a tail gas purification unit, wherein the Claus tail gas firstly undergoes hydrogenation to produce a hydrogenation tail gas comprising H2S, and introducing the hydrogenation tail gas into an absorption column, wherein H2S is absorbed in the absorption column to provide a purified tail gas; introducing a portion of the purified tail gas into the liquid sulfur tank as a stripping gas for degassing the liquid sulfur, wherein the purified tail gas is converted to a waste gas; and introducing the waste gas into the catalytic reaction unit, the tail gas purification unit, or a combination thereof.