SAPO-34分子筛催化氯甲烷制取低碳烯烃及再生性能考察

SAPO-34 molecular sieve catalyst for preparation of light olefins from chloromethane and its regeneration properties

在固定床反应器中考察了反应温度对SAPO-34分子筛催化氯甲烷反应的影响;同时考察了再生温度对SAPO-34再生性能的影响,并采用XRD、SEM、FTIR等方法对使用前后催化剂进行了表征。结果表明,当反应温度由400℃升高至475℃时,乙烯选择性随温度升高和反应时间延长而增大,丙烯选择性随反应温度升高和反应时间延长而减小;SAPO-34分子筛再生后,催化剂活性基本恢复,初始乙烯选择性明显增大,丙烯选择性减小;再生温度升高,初始乙烯选择性变化较小,丙烯选择性增大;对比表征结果发现,使用后催化剂与新鲜催化剂相比,结晶度有所下降,催化剂的形貌有一定程度的破坏,红外振动峰的位置与新鲜催化剂基本一致。

Conversion of chloromethane to olefins over SAPO-34 catalysts has been investigated at various temperatures in a fix-bed reactor. At the same time,the effect of the regeneration temperature on the regeneration performance of SAPO-34 is investigated. The catalyst is characterized by XRD,SEM,FTIR,and so on. The results show that by increasing reaction temperature and time,the selectivity to ethylene is gradually increased but the selectivity to propylene is reduced. After regeneration,the catalytic activity of SAPO-34 is basically recovered. Its initial selectivity to ethylene is clearly increased while its initial selectivity to propylene is slightly decreased. When the regeneration temperature increases,the initial selectivity to ethylene is slightly changed,but the initial selectivity to propylene is slightly increased. The characterization of the regenerated SAPO-34 shows that the crystallinity is decreased after regeneration. The morphology has a certain extent of damage. The infrared vibrational peaks are consistent with the fresh catalyst.