硫磺回收装置烟气碱法脱硫工艺存在问题及解决方案

Problems and solutions of flue gas alkali desulfurization process in sulfur recovery unit

关键词:  硫磺回收  烟气  碱法脱硫  SO₂  达标排放  含盐废水  GB 31570—2015 

Key words:  sulfur recovery  flue gas  alkali desulfurization  sulfur dioxide  up-to-standard emission  salinity wastewater  GB 31570—2015

摘要:

目的 对140 kt/a硫磺回收装置新增烟气碱洗单元的运行情况进行总结,分析烟气碱洗单元运行过程中出现的异常情况,并提出应对措施。方法 ①总结碱洗单元的运行情况,对操作参数及烟气排放情况进行分析；②将冲洗水由工业水改为除盐水,同时稳定控制碱液pH值,解决了烟气碱洗塔压降增大的问题；③优化工艺操作,对碱洗塔与循环槽连通管线进行改造,解决了碱洗塔液位波动的问题；④保证氧化空气供给,调整碱液pH值,防止急冷塔氨逃逸,解决了含盐废水超标的问题。结果 解决了烟气碱洗单元运行过程中出现的问题,该工艺单元于2017年7月建成投运,稳定运行至2022年3月装置大修,连续运行时间超过1 700 d。结论 实现了装置的长周期稳定运行,烟气中SO₂排放稳定达标,远低于排放标准的要求,可为同类装置提供参考。 

Abstract:

Objective The aims are to summarize the operation of new flue gas alkali desulfurization unit in 140 kt/a sulfur recovery unit, analyze the abnormal conditions during the operation of flue gas alkali desulfurization unit, and put forward corresponding countermeasures. Methods (1) The operation of the alkali desulfurization unit was summarized, and the operation parameters and flue gas emission were analyzed. (2) The flushing water was changed from industrial water to desalted water, and the pH value of lye was controlled stably, which solved the problem of rising pressure drop of flue gas alkali tower. (3) The connecting pipeline between the alkali desulfurization tower and the circulating tank was reformed to solve the problem of liquid level fluctuation in the alkali desulfurization tower. (4) By ensuring the supply of oxidized air, adjusting the pH value of alkali solution, and preventing the ammonia escape from the quench tower, the problem of excessive salinity wastewater was solved. Results The typical problems were solved in the operation of the flue gas alkaline desulfurization unit. This unit was put into run in July 2017 and operated stably until the overhaul in March 2022, with a continuous operation time of more than 1 700 days. Conclusion sThe long-term stable operation of the unit is realized, and the sulfur dioxide emission in the flue gas is up to the standard, which is far lower than the requirement of the emission standard. It can provide reference for similar devices.