变换冷凝液汽提净化改进工艺

Study on an Improved Process of Stripping Purification for CO Shift Condensate

目前,一氧化碳变换装置冷凝液的净化均采用蒸汽汽提+冷凝分离的工艺方式,通过汽提对变换冷凝液的净化效果良好,但产生的酸性气中因含氨而易导致酸性气在输送中形成碳铵结晶堵塞管道,且酸性气送入下游硫回收装置时,氨对其也会产生不良影响。当前应用较多的变换冷凝液双塔汽提工艺,虽然也能将变换酸性气中的氨含量降至较低水平,但都无法将氨完全去除,且流程较为复杂。针对以上问题,介绍了一种变换冷凝液汽提净化改进工艺,利用氨极易溶于水的特性,采用常温水吸收分离的方法,彻底去除了变换酸性气中的氨,与双塔汽提工艺相比,具有流程简单、设备少、投资低、占地少、操作成本低等优势,值得在变换装置冷凝液汽提系统中推广应用。

Currently,purification of CO shift unit condensate is usually materialized through steam stripping+condensation separation.Though stripping could lead to fairly purified CO shift condensate,the ammonia-containing acid gas from this process will cause crystalized ammonium bicarbonate to form and plug the conveying pipeline;moreover,when acid gas goes into the downstream sulfur recovery unit,the ammonia inside will also impose adverse effect on the unit.At present,twin-tower stripping is the mostly applied process for purifying CO shift condensate,which can reduce the ammonia content in the acid gas to a relatively low level,but it cannot remove the ammonia completely,and its process features relative complexity.In view of the above,an improved process of stripping purification for CO shift condensate is introduced,which takes advantage of the easy solubility of ammonia in water,and adopts normal temperature water for ammonia absorption and separation to completely eliminate the ammonia in CO shift acid gas.Compared with the twin-tower stripping process,this boasts such merits as simple process,small number of devices,low investment,low land occupancy,and low cost of operation,which make it highly recommendable for wider application in the CO shift condensate stripping system.