提高UDS溶剂脱除塔河油田伴生天然气中有机硫效率

Modification on UDS solvent for enhanced organosulfides removal from Tahe associated natural gas

为了解决新疆塔河油田伴生天然气中高含量有机硫的脱除难题,需开发高效脱硫溶剂。基于已在天然气净化领域工业应用的UDS-2溶剂的初始组成,采用量子化学计算并结合溶解度COSMO-RS模型预测优选提高甲硫醇(MeSH)溶解性能的溶剂组分,改进原UDS-2溶剂对MeSH的脱除性能,并分别在常压和高压吸收实验装置上对比考察不同溶剂对模拟塔河油田伴生天然气的吸收净化效果。结果表明,聚合度为5的聚乙二醇二甲醚(PEGDME-3)与MeSH分子之间的相互作用最强,对MeSH的溶解性能最好,相同条件下,MeSH在PEGDME-3中的亨利系数最小,40℃时的亨利系数为14.9 MPa·L/mol。PEGDME-3调配入原UDS-2溶剂中获得的改进UDS溶剂,对MeSH和总有机硫的脱除率较改进前原UDS-2溶剂分别提高了10.1%~11.4%和7.2%~8.5%。所得结论将有助于进一步提高UDS溶剂的有机硫脱除效率,满足塔河油田伴生天然气高含量有机硫的脱除净化需求。

Desulfurization solvent with high performance is required in order to effectively remove the high-content organosulfide compounds from the associated natural gas of Tahe Oilfield.Based on the original composition of UDS-2 solvent which had been developed and commercially applied in natural gas purification,optimum component with excellent removing efficiency for MeSH was screened via quantum calculation coupled with solubility predication using COSMO-RS model to enhance the performance of UDS-2 for MeSH removal.In addition,the purification performance of different solvents for simulated Tahe oilfield associated natural gas was evaluated under atmospheric and high pressure absorption conditions,respectively.PEGDME-3 having degree of polymerization of 5 showed the strongest intermolecular interaction with MeSH,which contributed to the highest solubility and the smallest Henry constant of 14.9 MPa·L/mol at 40℃.As compared to the parent UDS-2 solvent,the modified UDS solvent with the addition of PEGDME-3 was found to have 10.1—11.4 percentage points and 7.2—8.5 percentage points higher removal efficiencies for MeSH and total organosulfide respectively.As a result,the modified UDS solvent with largely enhanced removal efficiencies for organosulfides can be promising desulfurization solvent for the purification of Tahe associated natural gas containing high content of organosulfur compounds.