浅析忠县分厂硫磺回收装置尾气SO2排放影响因素和控制措施

Influencing factors and control measures of SO2 emission from sulfur recovery unit of Zhongxian Branch

关键词:  酸气组成  催化剂性能  SO₂减排  硫磺回收  脱硫

摘要:

通过对脱硫和硫磺回收装置进行分析可知,影响烟气中SO₂排放的主要工艺因素是原料气气质、气量的波动、酸气组成、脱硫溶液性能及催化剂性能。为了降低硫磺回收装置的SO₂排放,使其达到国家环保要求,主要采取了以下技术措施:①通过控制脱硫溶液质量分数及入塔温度,并适当降低溶液循环量,提高MDEA溶液的选择性；②及时更换失活催化剂；③在常规克劳斯段三级反应器添加SO₂选择性加氢催化剂,减少进入超级克劳斯段的SO₂含量；④优化停产除硫方案,缩短除硫时间。结果 表明,采取上述措施后,天然气净化装置的硫回收率稳定较高,排放烟气中SO₂质量浓度达到标准要求。 

Abstract:

Through the analysis on the desulfurization and sulfur recovery unit, it was concluded that the main process influence factors of SO₂ emission in flue gas were the fluctuation of feed gas composition and volume flow, the acid gas composition, the performance of desulfurization solution and catalyst. In order to reduce the SO₂ emission of the sulfur recovery unit and meet the national environmental protection requirements, the following technical measures were taken:(1) Improve the selectivity of MDEA solution by controlling the mass fraction of desulfurization solution and the solution temperature entering the absorption tower, and appropriately reduce the solution circulation. (2) Replace the deactivated catalyst in time. (3) Add SO₂ selective hydrogenation catalyst to the third-stage reactor of the conventional Claus section to reduce the SO₂ content entering the super Claus section. (4) Optimize the sulfur removal scheme, and shorten the sulfur removal time during plant production and shutdown. The results showed that after adopting the above measures, the sulfur recovery rate of the natural gas purification unit was stable high and the SO₂ mass concentration in the flue gas met the standard requirements.