6Cr/SiO_2催化剂上CO_2氧化乙烷脱氢制乙烯反应的研究

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 over 6Cr/SiO_2 catalyst

Oxidative Dehydrogenation of ethane with carbon dioxide to ethylene was investigated in a fixed bed micro-reactor under ambient pressure 6Cr/SiO 2 catalyst was found to be the best catalyst among SiO 2 supported different oxide catalysts and Cr 2O 3 supported on different support catalysts At 823K～923K,C 2H 4 selectivity of 85 2%～77 3% at a C 2H 6 conversion of 12 1%～32 1% could be achieved over the 6Cr/SiO 2 catalyst In this reaction, the increase of the ratio of CO 2/C 2H 6 enhanced the conversion of C 2H 6 and the yield of C 2H 4 with the increased of CO 2/C 2H 6 from 31 2% to 49 1% and from 24 8% to 35 1%,respectively Moreover, the effects of carbon dioxide on the dehydrogenation of C 2 H 6 to C 2 H 4 over Cr 2O 3 supported on different support catalysts were investigated To different supports, the role of carbon dioxide was obviously different Carbon dioxide exerted promoting effects only on AC and SiO 2 supported Cr 2O 3 catalysts However,carbon dioxide had an adverse effect on 6Cr/Al 2 O 3 and 6Cr/MCM41 catalysts The regeneration of the 6Cr/SiO 2 catalyst after C 2H 6 dehydrogenation with CO 2 was also attempted at 923K The original activity of the catalyst could not be recovered completely when CO 2 as a regeneration agent, while O 2 as a regeneration agent, the activity of the catalyst could be restored completely