Kinetic Modelling for the Dehydration of Methanol to Dimethyl Ether over silica doped ?-Al2O3

Scientific research in the field of energy has been focused on the findings of newer alternatives to that of conventional resources. The demand for the production of alternatives for clean energy sources has risen with the increase in depletion of oil reserves, environmental pollution, and to diversify energy resources for the country’s future energy security. More particularly, the emission of pollutants from C.I engines of automobiles has initiated the research for clean and diesel alternative fuel, such as Dimethyl Ether so that we could climb up towards green economy. DME appears to be a reliable option because it can be produced from non-fossil feedstocks, but also for its low greenhouse emissions, versatility and safety. It is well known that DME could be used as a proper substitute for diesel or LPG in the coming years as it is found to have high cetane number and ignition temperature near to that of diesel. DME, as a solution to environmental pollution and diminishing energy supplies, was synthesized more efficiently, compared to conventional methods, using a Bench-top fixed bed micro reactor unit for methanol dehydration to DME over Silica doped Alumina(SIRALOX-1 (Alumina 99% and Silica 1%) catalyst with high activity and stability. Even though, Alumina based catalysts are suitable with its weak to medium acidity, due to their hydrophilic nature, water adsorbs competitively with methanol. 2CH3OH ↔ CH3OCH3 +H2O ΔH= -21.225 kJ/mole Here in my work a kinetic model has been established for the dehydration of methanol to DME over γ-Al2O3 acid function. The kinetic model considers the reaction of methanol dehydration to be elementary. The effect of water in the reaction medium (due to the high adsorption capacity of γ-Al2O3) has been considered by adding a term to the reaction rate expression, which takes into account the partial inhibition of active site activity. Thirteen different models have been tested. The selection of the best model has been carried out on the basis of the Fisher test.