Study On The Hydrodesulfurization Kinetic Model For M-DSO Technology

Hydrosulfurization for fluid catalytic cracking (FCC) gasoline is the main technique to produce clean gasoline.The selective hydrosulfurization technologies for FCC gasoline and hydrodesulfurization kinetic models are summarized in this paper.Aiming at FCC gasoline hydrodesulfurization, the hydrodesulfurization kinetic model for M-DSO process was studied. The kinetic parameters of first and second order kinetic models were calculated by experimental data from fixed bed reactor. The results show that hydrodesulfurization of all single sulfides and total sulfur in M stage fit the first-order kinetic model, hydrodesulfurization of thiotolene, thioxene and total thiophene in DSO stage fit the second-order kinetic model, other single sulfides, total element sulfur and total sulfides in DSO stage fit the first-order kinetic model. The hydrodesulfurization models for M and DSO stages were revised by adding space velocity and hydrogen-oil ratio in kinetic equations. The modified models show good prediction performance.Effects of factors such as temperature, space velocity and hydrogen-oil ratio on sulfur removals were predicted by the established kinetic models. Results show that the removal of all kinds of total sulfur in DSO stage increases more quickly with the increase of temperature and hydrogen-oil ratio than that of M stage, and drops more quickly with the increase of space velocity than that of M stage.Based on comparison of desulfurization rate and activation energy for total sulfur in M and DSO stages for both M-DSO and DSO-M processes, the results show that no matter M or DSO stage is preposed, the activation energy of total sulfur will decrease, resulting in close desulfurization rate for DSO-M and M-DSO processes.