关键词: 天然气净化, 硫磺回收, SO₂减排, 含硫废气, 深度热备开工, 绿色停工, 零废液

Abstract:

GB 39728—2020 has put forward mandatory requirements on the emission limits of atmospheric pollutants from newly built and existing sulfur recovery units in natural gas purification plants. In an effort to reduce the emission concentration of SO₂ of tail gas and achieve the resource utilization of sulfur-containing waste gas, the process technology of sulfur recovery unit in high sulfur natural gas purification plant was optimized, including:(1)develop processes for recovering sulfur-containing waste gas from the liquid sulfur pool of large-scale sulfur recovery units, which introduces the waste gas from the liquid sulfur pool into the Claus furnace for sulfur element recovery;(2)develop deep hot standby start-up technology for large-scale sulfur recovery units, establishe an acidic gas interconnection network to reduce SO₂ emission during start-up;(3)develop green shutdown process for large-scale sulfur recovery units, which utilizes hot nitrogen sulfur blowing mode to achieve green shutdown. After optimization, when the unit load is 100%, the mass concentration of SO₂ of tail gas can be reduced to 197 mg/m³, with a reduction rate of 40%. During shutdown, the emission mass concentration of SO₂ of tail gas is much lower than that of methane sulfur blowing mode, with an average value of 237 mg/m³, and meets the SO₂ emission requirements of large-scale sulfur recovery units in GB 39728—2020.

Key words: natural gas purification, sulfur recovery, SO₂ emission reduction, sulfur-containing waste gas, deep hot standby start-up, green shutdown, zero waste liquid