空间位阻胺在有机硫脱除溶剂中的应用

Application of steric hindered amines in organic sulfur removal solvent

由于GB 17820—2018《天然气》中对总硫含量要求标准的提高,含有机硫天然气的净化气气质达标问题日益突出,急需研究出对天然气有机硫具有良好脱除效果的溶剂。总结了目前国内外常用的有机硫脱除溶剂类型,发现具有特殊结构的空间位阻胺对有机硫的脱除具有良好效果,选出具有潜在有机硫脱除效果的位阻胺类型。以空间位阻胺TBEE为例,从分子结构入手,分析了其具有有机硫脱除效果的原因,并搭建了相应的室内实验装置,实验对比了MDEA-水、MDEA-环丁砜-水及MDEA-TBEE-环丁砜-水溶剂的有机硫脱除效率,并对影响溶剂脱除效率的主要因素进行了分析,在其他操作因素不变情况下,吸收塔中的气液比和原料气中酸性气体浓度降低,则有机硫脱除率上升;填料高度和吸收塔压力降低,则有机硫脱除率降低。实验结果表明,在传统的物理—化学溶剂体系中加入一定量的TBEE后,可有效提高溶剂脱除硫醇类有机硫的效率。研究结果为天然气有机硫脱除提供了一种良好的工艺方法和思路,可在天然气有机硫脱除工程中进行应用。

With the increasingly stringent requirement of total sulfur content in the GB 17820—2018 Natural Gas standard of commercial natural gas,the specification of natural gas containing organic sulfur becomes more difficult to meet.There is an urgent need to study the solvents that have better natural gas organic sulfur removal effect.Firstly,a thorough review on organic sulfur removal solvents commonly used domestically and abroad shows that steric hindered amines with special structure have good effect on the removal of organic sulfur.The types of steric hindered amines which could potentially improve organic sulfur removal effect are then identified.The reason for and mechanism of TBEE to have better effect of organic sulfur removal is analyzed starting from the basic molecular structure approach.The corresponding laboratory test equipment has been set up,and the removal efficiency of organic sulfur by 3 types of solvent,namely MDEA-H 2O,MDEA-Sulfolane-H 2O and MDEA-TBEE-Sulfolane-H 2O was compared using laboratory test runs results.At the same time,the main factors affecting the solvent removal efficiency were studied.With other operating factors remaining unchanged,the removal rate of organic sulfur increased when the gas-liquid ratio in the absorber and the concentration of acid gas in the raw gas decreased.The removal rate of organic sulfur decreases with the decrease of packing height and absorber pressure.The experimental results shows that the removal efficiency of mercaptan organic sulfur can be effectively improved by adding a certain amount of TBEE into the traditional physicochemical solvent system.This research study provides a good process approach and idea for natural gas desulphurization,which can be applied in the natural gas projects processing gas containing organic sulfur.