Dehydrogenation of C12–C14 paraffins on PtCu/meso-structured Al2O3 catalyst for LAB production: Process simulation

The dehydrogenation of C12–C14 paraffins on PtCu/meso-structured Al2O3 catalysts for linear alkylbenzene (LAB) production was simulated to evaluate the effect of process variables. The new process consisted of a first stage where the paraffin is desulfurized, followed by second stage that used a novel dehydrogenation catalyst operating at high pressure and low temperature in trickle bed reactor. The dehydrogenation took place in the presence of an aromatic solvent, which helped control the catalyst deactivation. The process was modeled using Excel with a macro written in VB6. The hydrogen, C12 and benzene concentration in liquid phase was calculated using the Peng Robinson state equation. The kinetic rates and deactivation constants were previously determined and verified here with independent experiments. Analysis of mass and heat transfer controls indicated the presence of important diffusional limitations of the reactions in the pores at the inlet of the reactor operating conditions. The simulation confirmed that the system operates with low conversion (∼14–20%) and high selectivity, with only moderate deactivation. The use of a swing reactor helped to extend the cycle length without deteriorating the selectivity for one year cycle length commercial application; several options were evaluated to optimize the reactors system.