EMT分子筛的两步法制备及其在烯烃净化中的应用

Two-step Crystallization of EMT Zeolite and Its Application in Olefins Purification

采用两步法成功制备出纯相、高结晶度且形貌规整的EMT分子筛,并首次进行了颗粒状EMT分子筛(EMTPs)烯烃净化性能和热效应评价。结果表明,微波晶化温度不低于50℃、时间30~45 min可获得高结晶度EMT分子筛,水热晶化温度50℃、时间12~24 h可获得形貌规整的EMT分子筛。与颗粒状NaX分子筛(NaXPs)类似,EMTPs能将乙烯中初始物质的量分数为(10~1100)×10^-6的甲醇和丙醛两种极性含氧化物杂质深度脱除至10-6以下,但EMTPs具备更长的穿透时间、更高的穿透吸附容量及更低的热效应。多次再生实验表明,EMTPs具备良好的重复使用性能。初始杂质物质的量分数为10-3的乙烯体系中,EMTPs(100 g)对甲醇和丙醛的穿透时间分别为170.0和188.8 h,穿透容量分别为7.9和15.9 mg/g。

Pure EMT zeolite with high crystallinity and regular morphology had been successfully prepared by microwave-hydrothermal crystallization method(two-step). Moreover, the olefin purification performance and heat effect of granulated EMT zeolite particles(denoted as EMTPs) was firstly evaluated. The results indicated that high crystallinity EMT zeolite could be obtained with microwave crystallization temperature not less than 50 ℃ and time of 30-45 minutes,regular morphology EMT zeolite could be obtained with hydrothermal crystallization temperature of 50 ℃ and time of 12-24 hours. Similar to NaX zeolite particles(NaXPs), EMTPs could also deeply purify the trace amounts of polar methanol and propanal in ethylene to below 10-6 with the initial molar fraction of(10-1 100)×10-6. Compared with NaXPs, EMTPs exhibited longer penetration times, higher adsorption amounts and lower heat effect. The regeneration experiment further indicated that EMTPs had excellent reuse performance. In the ethylene system with an initial impurity content of 10-3, the penetration times and penetration amounts of methanol in EMTPs(100 g) were 170.0 h and 7.9 mg/g, and that of propanal were 188.8 h and 15.9 mg/g.