CO_(2)对硫磺回收装置尾气吸收及溶剂再生的影响

EFFECT OF CO_(2) ON TAIL GAS ABSORPTION AND SOLVENT REGENERATION OF SULFUR RECOVERY UNIT

炼油类和煤化工类硫磺回收装置尾气(简称硫回收尾气)最主要的差别是CO_(2)含量不同。采用加氢还原-吸收工艺,以甲基二乙醇胺(MDEA)溶液为溶剂,以分别来自炼油类硫磺回收装置、煤化工类富氧硫磺回收装置和煤化工类纯氧硫磺回收装置的3类典型的硫回收尾气为研究对象,考察了CO_(2)对尾气吸收及溶剂再生的影响,结果表明:CO_(2)影响MDEA溶液对H2S的吸收效果,随着CO_(2)含量增加,需要的MDEA溶液循环量增加,MDEA溶液浓度增加,溶剂再生时蒸汽消耗量也增加。对于CO_(2)含量高的煤化工类硫回收尾气,宜使用高浓度高效溶剂以降低溶剂循环量和蒸汽消耗量,减少酸性气返回制硫炉的绝对量,或者选择短流程硫磺回收工艺。

The main difference between the tail gas of sulfur recovery units in refinery and coal chemical industry is the difference of CO_(2) content.In this paper,the hydrogenation reduction and absorption process were used,and the solvent was methyl diethanolamine(MDEA)solution.Three types of typical sulfur recovery tail gas from refinery sulfur recovery unit,coal chemical oxygen-enriched sulfur recovery unit and coal chemical pure oxygen sulfur recovery unit were studied,and the effects of CO_(2) on the absorption of tail gas and the regeneration of solvent were investigated.The results showed that the CO_(2) affected the absorption of H2S by MDEA solution.With the increase of content of CO_(2),the required circulation amount of MDEA solution and the concentration of MDEA solution increased,steam consumption also increased during solvent regeneration.For the tail gas of sulfur recovery from coal chemical industry with high CO_(2) content,high concentration and high efficient solvent should be used to reduce the amount of solution circulation and steam consumption,and to reduce the absolute amount of acid gas returning to sulfur making furnace,or choose a short-process sulfur recovery process.