Steam Reforming of Hydrocarbons on Alkali Polyaluminate Catalysts (Part. 2)

The reaction between steam and carbon deposited on potassium polyaluminate-(β"-Al2O3) from various hydrocarbons was studied in tubular flow reactor with a fixed catalyst bed at elevated temperatures.Carbon deposition fiom n-hexane took place above 600°C, while that from benzene required temperatures higher than 700°C. The reaction between steam and carbon deposited from both n-hexane and benzene, however, proceeded above 600°C. The lowest temperature required for steam reforming on β"-Al2O3 catalyst was decisively dependent on the ease of cracking of feed hydrocarbon to form carbon deposits.The reactivity of carbon with steam deposited from polyaromatic hydrocarbons was almost the same as that from benzene. On the other hand, carbon deposited from n-hexane or ethylene was somewhat less reactive than that from aromatics.By comparing the reaction between steam and several carbon species with different degree of graphitization in the presence of β"-Al2O3, it was shown that intermediate carbon deposited on β"-Al2O3 during steam reforming was as reactive as amorphous charcoal.