Industrial Feasiblity of Direct Methane Conversion to Hydrocarbons over Fe-Based Fischer Tropsch Catalyst

摘要

Recently, as a direct consequence of the dwindling world oil reserves and the growing awareness of the environmental problems associated with the use of coal as energy source, there is growing interest in cheaper, abundant and cleaner burning methane. The Gas-to-Liquid technology offers perhaps the most attractive routes for the exploitation of the world huge and growing natural gas resources. Using this process the erstwhile stranded gas is converted to premium grade liquid fuels and chemicals that are easily transported. However, a widespread application of the GTL process is being hampered by economical and technical challenges. The high cost of synthesis gas, for instance, weighs heavily on the economics and competitiveness of the process limiting its wider application. This work presented a modified Gas-to-Liquid process that eliminates the costly synthesis gas production step. The proposed process utilized an alternative pathway for methane activation via the production of chloromethane derivatives which are then converted to hydrocarbons. It established that hydrocarbons mainly olefins can be economically produced from di- and tri-chloro- methanes over a typical iron-based Fischer Tropsch catalysts in a moving bed reactor at industrially relevant conditions. Some of the attractions of the proposed process include a) the elimination of the costly air separation plant requirement b) high process selectivity and c) significant reduction of carbon dioxide emissions thereby saving on feedstock loss and the costly CO2 removal and isolation processes.