Cu(I)-Ce(IV)-Y吸附剂的制备及其脱硫性能研究

采用液相离子交换Cu、Ce离子制备了Cu(I)-Y、Ce(IV)-Y和Cu(I)-Ce(IV)-Y吸附剂,利用XRD、BET等技术对吸附剂进行了表征。通过静态实验考察了制备条件对Cu(I)-Ce(IV)-Y吸附剂脱硫性能的影响,通过固定床实验研究了吸附剂的穿透硫容,同时,在含噻吩与苯并噻吩的正辛烷模拟油中,分别加入甲苯、环己烯、吡啶配成新的模拟油,探究了吸附剂的脱硫选择性。结果表明,离子交换时间48 h,焙烧温度550℃,Cu/Ce物质的量比1∶1下制备的Cu(I)-Ce(IV)-Y吸附剂具有适宜的脱硫活性。在含甲苯、环己烯模拟油中,Cu(I)-Ce(IV)-Y吸附剂具有最好的脱硫性能,相同浓度的甲苯、环己烯和吡啶对各吸附剂脱硫性能的影响顺序为吡啶环己烯甲苯。引入Cu+可改善吸附剂的脱硫活性,引入Ce4+可改善吸附剂对硫化物的选择性,Cu+和Ce4+的协同作用使Cu(I)-Ce(IV)-Y兼具有高的硫容和抗芳烃、烯烃能力。

Preparation of Cu(I)-Ce(IV)-Y adsorbent and its adsorptive desulfurization performance

Cu(I)Y, Ce(IV)-Y and Cu(I)-Ce(IV)-Y adsorbents were successfully prepared by liquid-phase ion-exchange of Y zeolites with combined Cu and Ce ions. The adsorbents were characterized by means of X-ray diffraction (XRD) and N₂-adsorption specific surface area measurements (BET). The effect of preparation conditions on the adsorptive desulfurization properties over Cu(I)-Ce(IV)-Y were studied by a static desulfurization method. The breakthrough sulfur capacities of the adsorbents were studied in a fixed-bed reactor system. Meanwhile, adsorptive desulfurization selectivities of the adsorbents were studied through model fuels, which made up of 1-octane solution of benzothiophene and thiophene, then respectively mixed with a certain amount of toluene, cyclohexene or pyridine. The results indicate that the optimum preparation conditions of Cu(I)-Ce(IV)-Y is ion-exchange time of 48 h, Cu/Ce molar ratio of 1, and calcination temperature of 550 ℃. Cu(I)-Ce(IV)-Y adsorbent exhibited the best desulfurization performance with model fuels, which contain a certain amount of toluene and cyclohexene. The effect of toluene, cyclohexene and pyridine at the same concentration, on the metal ion-exchanged Y zeolites for sulfur removal is in the order: pyridine > cyclohexene > toluene. The introduction of Cu⁺ can improve the desulfurization activity of adsorbent, while the introduction of Ce⁴⁺ can improve the selectivity of adsorbent. The synergistic effect of Cu⁺ and Ce⁴⁺ contribute to Cu(I)-Ce(IV)-Y not only has the high sulfur adsorption capacity but also has the ability of resistance to aromatics and olefins.