A Model for the Kinetic of Catalytic Hydrogenation of Carbon Dioxide as the Key Process in Continuous CO2 Recycle

Environmental concern regarding the formation and accumulation of green housegases, in particular, carbon dioxide has persuaded the individual researchers and scientificinstitution to perform extensive studies on reduction and elimination of the latter gas. Recently, application and continuous recycle of carbon dioxide in a special power generation cycle has attracted a considerable attention. In such as cycle, Called Continuous CO2 Recycle (CCR), carbon dioxide is first hydrogenated to methane and water. Methane is then applied either in a fuel cell or in a gas turbine cycle to generate electrical energy. A part of the generated power is allocated to the electrolysis of water and the resulting hydrogen gas is consumed in hydrogenation step which may be regarded as the key reaction in CCR processes. In the present study, catalytic hydrogenation of carbon dioxide has been conducted in a packed bed reactor. Formulation of an active catalyst and the determination of optimum operating parameters have been achieved within a research frame work applying Taguchi experimental design method. It was found that the catalyst consisted of 3% nickel supported on Na-Y zeolite demonstrated the highest activity 20 bar; molar feed ³ and the optimum operating conditions were established as, T= 230 °C; P in addition, a mechanism for hydrogenation of CO2, based on ratio (CO2 /H2) = 65/35. Langmuir-Hinshelwood formulation, was presented from which, a kinetic model was derived and the kinetic parameters were determined as functions of temperature