关键词: 脱硫溶剂, 天然气, 有机硫, 甲硫醇脱除, 相平衡

Abstract: The active component that can enhance the adsorption for MeSH was successfully screened by applying quantum chemistry computation method and then was formulated mixed with the original UDS solvent to obtain a modified high efficiency UDS solvent. The equilibrium solubilities of MeSH in the original UDS solvent and the updated solvent were investigated and compared. In addition, the thermal stability and anti-foaming performance of both UDS solvents were evaluated. The absorption experiments were conducted in an atmospheric unit using simulated Chuanxi natural gas as raw material. The results indicate that polyethylene glycol dimethyl ether (PEGDME) has the strongest intermolecular interaction with MeSH molecule, therefore, is expected to be the promising component for improving the removal of MeSH. As compared with the original solvent, the improved UDS solvent shows a higher solubility of MeSH and has a better thermal stability and anti-forming performance. The modified solvent has 10.3 percentages higher removal rate of MeSH and the total sulfur content decreases in purified gas from 70.0 mg/m3 to 54.1 mg/m3, 5.7 percent points higher than original one at the adsorption conditions of gas/liquid volume ratio of 360 and absorption temperature 40 ℃, and atmospheric pressure. The gas quality is improved from the national standard II to the top one.

Key words: desulfurization solvent, natural gas, organosulfur, methyl mercaptan removal, phase equilibrium