6Cr/SiO_2催化剂上CO_2氧化乙烷脱氢制乙烯反应的研究

Oxidative dehydrogenation of ethane with carbon dioxide to ethylene over 6Cr/SiO_2 catalyst

在常压固定床微反反应器上 ,对CO2 氧化乙烷脱氢制乙烯反应催化剂进行了评价。通过对载体及活性组份的筛选 ,发现 6Cr/SiO2 催化剂具有较佳的催化反应性能。温度在 82 3～ 92 3K之间 ,该催化剂的乙烷转化率和乙烯选择性分别为1 2 1 %～ 3 2 1 %和 85 2 %～ 77 3 %。增加V(CO2 ) /V(C2 H6 ) ,有利于提高乙烷转化率和乙烯产率 ,随V(CO2 ) /V(C2 H6 )从1 0增加到 4 0 ,乙烷转化率从 3 1 2 %增加到 49 1 % ,乙烯产率从 2 4 8%增加到 3 5 1 %。另外 ,考察了Cr担载在不同载体上CO2 对乙烷脱氢的作用。对于 6Cr/SiO2 和 6Cr/AC催化剂 ,CO2 对乙烷脱氢起促进作用 ,而对于 6Cr/MCM41和 6Cr/Al2 O3催化剂 ,CO2 对乙烷脱氢却起抑制作用。对 6Cr/SiO2 催化剂上CO2 氧化乙烷脱氢制乙烯反应的再生实验也进行了探讨。结果表明 ,在 92 3K下反应后的催化剂用O2 可完全再生 ,而用CO2 则不能完全再生。

Oxidative dehydrogenation of ethane with carbon dioxide to ethylene was investigated over SiO 2 or active carbon(AC) supported different metal oxide catalysts. Chromium oxide was found to be the best active component.At 823～923K, the conversion of C 2H 6 over 6Cr/SiO 2 catalyst and 6Cr/AC catalyst were 12.0%～32.1% and 8.5% ～29.2% respectively; the selectivity of C 2H 4 over the catalysts were 85.2%～77.3% and 87.5% ～69.6% respectively. The effects of CO 2 on the dehydrogenation of C 2H 6 over 6Cr/SiO 2 catalyst and 6Cr/AC catalyst were also investigated.It showed that carbon dioxide facilitated the dehydrogenation of ethane and enhanced ethane conversion and ethylene yield. Moreover,coke deposition on the two catalysts was retarded greatly in the presence of carbon dioxide.