低温甲醇洗循环甲醇有机硫化物定性和定量研究

Qualitative and quantitative research about organic sulfides in recyclemethanol of Rectisol

对某厂低温甲醇洗系统循环甲醇中3种典型含硫甲醇有机硫化物进行定性和定量分析,寻找净化气总硫超标的问题根源,文中采用有机元素分析仪和微量硫气相色谱仪对其低温甲醇洗系统循环甲醇典型代表流股——预洗甲醇、回流甲醇和贫甲醇中有机硫化物种类进行了定性和定量研究。分析结果表明:预洗甲醇和回流甲醇中除硫化氢外,还含有大量二氧化硫、甲硫醇、乙硫醇、正丙硫醇和正丁硫醇;贫甲醇(再生后甲醇)中二氧化硫质量分数46.68μg/g,正丁硫醇8.70μg/g,硫化氢3.74μg/g,正丙硫醇1.94μg/g,二甲基二硫醚1.26μg/g,乙硫醇1.58μg/g,甲硫醇0.93μg/g,羰基硫0.24μg/g,说明该厂低温甲醇洗系统中甲醇再生不彻底,循环甲醇中存在二氧化硫及硫醇类物质的累积是造成净化气总硫超标原因之一。

In order to find the root cause of total sulfur in the purified gas exceeding the standard,three typical organic sulfides containing sulfur-methanol were analyzed qualitatively and quantitatively.The three organic sulfides were taken from recycled methanol of the Rectisol in a plant.In this paper,multi EA 5000 and GC were used to analyze the types of organic sulfides in typical stream qualitatively and quantitatively.The typical streams included prewash methanol,reflux methanol and lean methanol.The results show that prewash methanol and reflux methanol contain a large amount of sulfur dioxide,methyl mercaptan,ethyl mercaptan,n-propyl mercaptan and n-butyl mercaptan,in addition to hydrogen sulfide.Lean methanol contains 46.68μg/g sulfur dioxide,8.70μg/g n-butyl mercaptan,3.74μg/g hydrogen sulfide,1.94μg/g n-propyl mercaptan,1.26μg/g dimethyl disulfide,1.58μg/g ethyl mercaptan,0.93μg/g methyl mercaptan,0.24μg/g carbonyl sulfur.It shows that the methanol regeneration in the Rectisol of the plant is incomplete.The accumulation of sulfur dioxide and mercaptan in recycled methanol is one of the reasons for the excessive total sulfur in the purified gas.