Hydrocarbon trap is an effective way to solve the diesel cold start emissions. Zeolites used as hydrocarbon adsorbents are paid more and more attention. In order to study the diffusion of diesel cold start emissions in zeolites, molecular dynamics(MD) in canonical ensemble are employed to simulate the diffusion of ethylene and propylene in MCM-22 in different ways, the mean square displacement (MSD) plot, diffusion coefficient for pure and mixed components are obtained-. The simulation results show that, propylene (C3H6) and ethylene (C2H4) have different diffusion coefficients in MCM22 zeolite at the same temperature; for the same gas, it also has different diffusion coefficients at different temperatures. In addition, the diffusion coefficient increases with temperature rise, thus temperature rise is beneficial to accelerate diffusion process.
CuH-ZSM-5 as Hydrocarbon Trap under Cold Start Conditions
