基于分子管理的脱有机硫复配型溶剂的开发与应用

基于分子管理理念, 对脱有机硫复配型溶剂进行组成设计。采用两维溶解度参数理论, 筛选出与甲硫醇溶解度参数接近的溶剂作为复配溶剂中提高甲硫醇脱除率的组分;并根据胺的碱性、空间位阻效应对其与COS反应速率的影响规律, 选择具有较小空间位阻效应和适当强度碱性的环状胺类作为提高COS脱除率的溶剂组分。根据原料气的有机硫分布特点, 将所筛选的溶剂组分按一定比例配入N-甲基二乙醇胺(MDEA)中, 获得了两种复配溶剂(UDS-I, UDS-II)。脱硫实验结果表明, 对于COS占有机硫总量94%的天然气, UDS-I溶剂的COS脱除率较MDEA高出近44个百分点, 其净化天然气质量满足一类气的指标要求;对于甲硫醇占有机硫总量79%的焦化液化气, UDS-II溶剂的甲硫醇脱除率较MDEA高出近50个百分点, 其净化液化气的总硫含量满足民用液化气指标要求。

Development and application of formulated solvents based on molecular management theory for removing organic sulfur

Based on the molecular management theory, the rational formulations of mixed solvents for removing organic sulfurs were designed. Using a two-dimensional solubility parameter theory, the solvents, with similar solubility parameters for methyl mercaptan as compared with alkanolamines, were selected as key components of formulated solvents to remove methyl mercaptan. According to the influence of basicity and steric hindrance of amines on the reaction rates of amines with carbonyl sulfide, the heterocyclic amines with less steric hindrance and moderate basicity were used as key components to enhance removal efficiency for carbonyl sulfide. Depending upon the distributions of organic sulfur in feed gases, the selected solvent components were added to N-methyl diethanolamine (MDEA), then two kinds of formulated solvents (UDS-I and UDS-II) were obtained. The results of desulfurization experiments showed that for the natural gas in which carbonyl sulfide accounted for 94% of total organic sulfur, removal efficiency for carbonyl sulfide with UDS-I was approximately 44 percentage points higher than that of MDEA. The purified natural gas well satisfied the requirement of first-grade commercial gas. For the delayed coking LPG in which methyl mercaptan accounted for 79% of total organic sulfur, removal efficiency for methyl mercaptan of UDS-Ⅱ was about 50 percentage points higher than that of MDEA. The purified LPG could be directly used as civil LPG.