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

摘要：

GB 39728—2020《陆上石油天然气开采工业大气污染物排放标准》对新建及现有天然气净化厂硫磺回收装置大气污染物排放限值提出了更高的要求。为降低尾气SO₂排放浓度，实现含硫废气资源化利用，对高含硫天然气净化厂硫磺回收装置工艺技术进行了优化：(1)开发大型硫磺回收装置液硫池含硫废气回收工艺，将液硫池废气引入克劳斯炉进行硫元素回收；(2)开发大型硫磺回收装置深度热备开工技术，建立酸性气联通网，减少开工期间SO₂排放；(3)开发大型硫磺回收装置绿色停工工艺，利用热氮吹硫实现绿色停工。技术优化后，装置负荷100%时，尾气SO₂质量浓度可降至197 mg/m³,减少排放40%;停工期间，尾气SO₂排放浓度远低于甲烷吹硫模式，平均值可达237 mg/m³,满足GB 39728—2020对大型硫磺回收装置的SO₂排放要求。

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