The Effects of Promoter on Catalytic Performance of Cr_2O_3 Nano-composite Catalysts in Oxidative Dehydrogenation of Ethane with CO_2 to Ethylene

摘要

Up to now, ethylene is predominantly produced by steam cracking of naphtha, ethane or liquid petroleum gas at high temperatures with short residence time. With the increasing need for ethylene and the decreasing storage of petroleum, it is necessary to develop alternative routes for the ethylene production. Recently several attempts have been made to utilize carbon dioxide (the major greenhouse gas) as a mild oxidant for dehydrogenation of ethane to yield ethylene. In general, this process provides several advantages such as lower reaction temperature, longer operation period and no formation of C_3~+ and C_2H_2 compared with conventional dehydrogenation of ethane to yield ethylene. Furthermore, syn-gas can be obtained as a by-product for this process. However, some side reactions occur when carbon dioxide is employed as the oxidant. It is necessary to find a new catalyst with not only high conversion but also high selectivity In the past decade, nano-particle (especially, oxides) .attracted much attention in the field of heterogeneous catalysis due to their unique physical and chemical properties. Many efforts have been devoted to prepare nano-particle catalysts and a number of interesting results have been obtained for different catalytic reactions. In recent years, several researchers have explored the chromium-based catalysts for the oxidative dehydrogenations of ethane in the presence of carbon dioxide.