Optimum temperature profile for endothermic conversions in tubular reactors

Abstract

AbstractThe thermal conversion of petroleum hydrocarbons and organic chemicals in tubular, continuous flow reactors is an important operation in the manufacture of synthetic organic chemicals. The processes, usually conducted at rather high temperatures, are generally endothermic and require more or less intense application of heat. The temperature profile as well as the heat transfer rate in the conversion zone must be compatible with the product distribution in order to avoid excessive side reactions. Equilibrium relationships furnish guiding criteria for the adequacy of operating conditions with the state of conversion.The sensitivity of pyrolysis products to temperature and heat intensity is quite different for individual reactants, precluding a generally valid approach to optimizing temperature gradients in thermal conversion processes. Therefore, the pyrolysis of propane has been studied in detail and the method evolved for establishing the optimum temperature profile in the reaction coil. The state of the reactant mixture at any point in the conversion process is defined in terms of a few basic variables by correlations permitting the application of modern electronic computers in the analysis of the conversion process and verification that optimum conditions will prevail with respect to the conversion product distribution. An outline of the computer operation is given.