Reaction Kinetics of Propane Catalytic Combustion on Cr/γ-Al2O3, Co/Cr/γ-Al2O3, and Au/Cr/γ-Al2O3

丙烷在Cr/γ-Al2O3，Co/Cr/γ-Al2O3，及Au/Cr/γ-Al2O3上之催化燃燒反應動力研究

林俊男(Jiunn-Nan Lin) ； 萬本儒(Ben-Zu Wan)

《Journal of the Chinese Institute of Chemical Engineers》 35卷2期 (2004/03) Pp. 149-159

https://doi.org/10.6967/JCICE.200403.0149

摘要

本研究是在反應溫度563-593K及一大氣壓條件下，研究丙烷在Cr/γ-Al2O3，Co/Cr/γ-Al2O3，及Au/Cr/γ-Al2O3上之催化燃燒反應動力機制，並已結論出經由觸媒之還原及氧化機制所推導出之反應速率方程式是最適合於各反應動力實驗數據。該機制顯示出添加Co之Co/Cr/γ-Al2O3觸媒，其被丙烷還原之速率遠高於Cr/γ-Al2O3，因此丙烷在Co/Cr/γ-Al2O3上之催化燃燒速率遠快於Cr/γ-Al2O3上。添加Au之Au/Cr/γ-Al2O3其初始反應活性甚至高於Co/Cr/γ-Al2O3，但該觸媒有結碳及失活的缺點。本研究已由反應速率常數與溫度之關係推導出在Cr/γ-Al2O3及Co/Cr/γ-Al2O3上之活化能及速率常數，因此添加Co而增加Co/Cr/γ-Al2O3活性之原因，將藉由這些活化能數據在文中詳加討論。

並列摘要

The kinetics of propane oxidation to carbon dioxide and water over Cr/γ-Al2O3, Co/Cr/γ-Al2O3, and Au/Cr/γ-Al2O3 were investigated within the temperature range 563-593K at atmospheric pressure. The rate equations for all three catalysts were obtained in this research. A best-fit reduction-oxidation mechanism was found for the reaction. On the basis of the kinetic analysis, it is concluded that the existence of cobalt in Co/Cr/γ-Al2O3 can increase the reducibility of chromium oxides; therefore, the reaction rate over Co/Cr/γ-Al2O3 was more than that over Cr/γ-Al2O3. Gold in Au/Cr/γ-Al2O3 also enhanced the rate of propane oxidation; its initial activity was even higher than that of Co/Cr/γ-Al2O3. However, duemainly to coking, there was a significant decay problem on the surface of Au/Cr/γ-Al2O3during the reaction. Moreover, the activation energies and the Arrhenius constants for the reduction and the oxidation steps on Cr/γ-Al2O3 and Co/Cr/γ-Al2O3 during complete propane oxidation were obtained. The promotion effect from cobalt oxides on chromium oxides with respect to the activation energies is discussed.

並列關鍵字

Catalytic combustion ； Chromium oxides ； Propane ； Oxidation ； Gold ； Cobalt