Abstract:

During the operation of a natural gas purification plant, there are phenomena such as the shutdown of the hydrogenation furnace, the inability to execute the automatic switching interlock of the tail gas, and the excessive sulfur dioxide content in the flue gas. Through investigation and analysis, it is determined that these phenomena are caused by sulfur accumulation in sour gas pipe of tail gas treatment part of sulfur recovery unit. When the sour gas(135 ℃) carrying liquid sulfur and sulfur vapor merges with the pipeline medium(41 ℃) with lower temperature at the top of the absorption tower, condensation occurs due to the long confluence section. Due to the corrosiveness of sour gas, its condensate can corrode pipes, cause valve jamming and internal leakage. Due to the constraints of shutdown maintenance cycles and sulfur accumulation on site, the on-site solution is to shorten the length of the confluence section and increase local heat tracing. In terms of design, optimization schemes such as changing the equipment layout, increasing pipe slope, and high point layout of valves that are prone to jamming and internal leakage have been adopted to solve the problem of sulfur accumulation in sour gas pipes.

Key words: sulfur recovery, tail gas treatment, sour gas pipe, sulfur accumulation, length of confluence section, high point layout of valves

摘要：

某天然气净化厂在运行过程中出现加氢炉停车、尾气自动切换联锁无法执行、烟气二氧化硫含量超标等现象。通过排查和分析，确定这些现象是由硫磺回收装置尾气处理单元酸性气管道积硫问题导致的。夹带着液硫和硫蒸气的酸性气(135℃)与吸收塔塔顶温度较低的管道介质(41℃)汇合时，因汇合段过长发生了冷凝。由于酸性气具有腐蚀性，其凝液会腐蚀管道、导致阀门卡涩和内漏。受停工检修周期及现场积硫情况的制约，现场采取了缩短汇合段长度并局部增加伴热的解决方案。设计上，通过采取改变设备平面布置、增加管道坡度、易卡涩和内漏的阀门高点布置等优化方案，解决了酸性气管道的积硫问题。

关键词: 硫磺回收, 尾气处理, 酸性气管道, 积硫, 汇合段长度, 阀门高点布置