Simulation of light naphtha dimerization using a PtZrGa/Si mesoporous catalyst in a swing mode of operation

A new process for selective dimerization of commercial cracked light naphtha (C4–6) into gasoline-range molecules (C7–11) was simulated. The reaction takes place at a low-hydrogen partial pressure in the presence of a PtZrGaOx/ZrSiOy mesoporous catalyst. The apparent kinetic rates of reactions and deactivation models, previously determined in microplant tests, were confirmed with three experimental one-week tests. The kinetic for catalyst regeneration was then determined on these spent catalysts. The simulation results show that the use of two swing-axial gas-phase reactors operating in parallel but out of phase by one week produce the best economical cycle of operation. That occurred when the increase in temperature as function of time at the inlet of each bed follows a particular ratio. The regeneration of the spent catalyst by solvent and hydrogen recovers most of the activity and all the selectivity. The fresh, spent and regenerated catalysts’ properties are briefly described.