Diffusion Behavior Of Model Diesel Components In Polymer Membranes By Molecular Dynamic Simulation And Experimental Study

The importance of diesel desulfurization has attracted the attention of the countries all over the world. We aim to achieve to the desulfurization by improving the selectivety of activated carbons, the method is to coat the adsorbent with a certain polymer membrane.Molecular mechanics (MM) and Molecular dynamics (MD) simulation were used and COMPASS force field was adopted to discuss the diffusion properties of the model diesel components in different polymer membranes.The composite material of ACstyrene covered with PVA membrane (ACstyrene-PVA) was used to adsorb DBT and MNA of model diesel components. The results revealed that the pseudo-second order kinetic equation was relatively accurate, and the PVA membrane was beneficial to the diffusion of DBT in the batch adsorption and fixed-bed adsorption experiments.Molecular dynamic (MD) simulation was used to investigate the diffusion behavior of the DBT/MNA and DBT/Quinoline systems in the different polymer membranes. The diffusion coefficients of DBT, MNA and Quinoline were calculated, and it was indicated that the MD method was probable to roughly predict and elucidate the diffusion behavior of the model diesel components in polymer membranes in this study by comparing the simulation with experimental results. And it was obviously discovered that the PVC membrane was the only material improving the diffusion selectivity of DBT over MNA and the PVA membrane was the only material improving the diffusion selectivity of Quinoline over DBT in this study, which demonstrated that the PVC membrane might be beneficial to diesel desulfurization and the PVA membrane might be beneficial to diesel denitrification. The micro diffusion mechanism of diffusion molecules inside polymer membrane was investigated by analyzing three aspects, and it was concluded that interaction energy was the key factor for all the polymer systems.