Özet:
The overall purpose of this research study is to design and develop effective Cobased bimetallic catalyst supported on zirconia for the production of synthesis gas via CO2 reforming of methane (CDRM). In order to increase the oxygen storage capacity of the catalyst, Ce was used as a promoter. The type of carbon deposited on catalysts during reactions performed under various reaction conditions was investigated to understand the effect of those conditions on type and abundance of coke formation. The reaction temperature, feed ratio and space velocity were the parameters used in activity and selectivity tests; activity was determined in terms of CH4 and CO2 conversions and selectivity was determined in terms of H2/CO product ratio in the product stream. Characterization of the 5 % Co-2 % Ce/ZrO2 catalyst indicated uniformly distributed metal particles allowing reactants to access the appropriate sites. The type of carbon deposited on catalysts under different reaction conditions was all filamentous. It was also clearly observed that the parts of the catalyst particles having high Ce/Co ratios have less carbon deposition, remarking the effect of ceria on the catalyst activity. On the basis of the performance test results, it was concluded that increasing temperature increased CH4 and CO2 conversions and H2/CO product ratio. CH4/CO2 feed ratio of 2/1 gave the lowest methane conversion but the highest values for carbon dioxide conversion and H2/CO product ratio. On the other hand, CH4/CO2 feed ratio of 1/1 presented similar results for carbon dioxide conversion and H2/CO product ratio with increased methane conversion. Additionally, it was found out that increasing space velocity decreased the conversion values and H2/CO product ratio without affecting the stability profile. Considering all of these parameters, it was suggested that CH4/CO2 ratio of 1/1 with high temperature and low space velocity were the optimum reaction conditions for CDRM over Co-Ce/ZrO2 system.
