DEHYDROGENATION OF PROPANE INA POROUS MEMBRANE REACTOR: MODELING STUDY

Abstract

A mathematical model is presented to investigate the performance of Catalytic membrane reactor for dehydrogenation of propane using a Vycor glass porous membrane. Propane dehydrogenation is an equilibrium limited and highly endothermic reaction (AH° = -118 KJ/mole) that is often carried out at high temperatures and atmospheric pressure using platinum or chromium catalysts. Kinetic equations for platinum catalyst given by languirhinshelwood kinetic model are taken for the one dimensional steady state pseudohomogeneous model. Both mass and energy balance are done on all the components and also all the side reactions are considered. The membrane used is highly permeable to hydrogen as compared to both propane and propene hence the membrane is employed to shift the equilibrium and to achieve higher conversion. For a simple tubular reactor six simple ODE's are formed for each component and one ODE is formed as a result of energy balance whereas for membrane reactor 12 ODE's are formed as a result of mass balance two for each component and one as a result of energy balance. These model equations are solved simultaneously using ODE solver in MATLAB. The performance of membrane reactor has been analysed and compared with traditional fixed bed reactor in terms of propane conversion, product yield and selectivity. The conversion increases from 42.67% to 65.3 1% by replacing the tubular reactor with a membrane reactor at a reaction temperature of 500 °C. Also maximum conversion corresponds to a temperature of about 525 °C. The studies show that the conversion is also affected by mole ratio of the reactants and flow rate of helium which is used as a purge gas.