Dynamic modeling and simulation of heavy paraffin dehydrogenation reactor for selective olefin production in linear alkyl benzene production plant Original Research Article

Modeling of a heterogeneous industrial fixed bed reactor for selective dehydrogenation of heavy paraffin with Pt–Sn–Al2O3 catalyst has been the subject of current study. Using mass balance, momentum balance for appropriate element of reactor and applying pressure drop, rate and deactivation equations, a detailed model of the reactor has been obtained. Mass balance equations have been used for five different components. In order to investigate reactor performance in time, the reactor model which is a set of partial differential equations (PDEs), ordinary differential equations and algebraic equations has been solved numerically.Variation of paraffins, olefins, dienes, aromatics and hydrogen mole percent as a function of time and reactor radius have been found by numerical solution of the model. Modeling results have been compared with an industrial reactor data at different operating times. The comparison successfully confirms validity of the proposed model. It was found that at radius of 0.75–0.68 m of catalytic bed, there is not sensible conversion of paraffin as surface reaction is rate determining. At entrance of the bed variation of diene was near zero. Hydrogen production was high at entrance of the catalytic bed. Hydrogen production decreases along the reactor bed because of olefin cracking.