Effect of external pressure on the release of methane through MFI zeolite nanochannels.

In this work, the effects of external pressure on the release of methane through zeolite nanochannels are studied through molecular dynamics (MD) simulations. The release percentage of methane under three types of pressure loadings with various strengths and frequencies are obtained. Specifically, constant, sawtooth-shaped, and sinusoidal pressures are examined. As the pressure strength is increased, it is found that the release percentage first decreases and then increases significantly before finally approaching a constant. At sufficiently high pressures, the release percentage of methane under constant external pressure is about 65%, while it reaches over 90% for sawtooth-shaped and sinusoidal pressures. The loading frequency for periodic external pressures appears to be unimportant compared with the effect of the pressure strength. Theoretical predictions of the release percentage are made on the basis of the kinetic energy of methane molecules and the energy barrier inside the nanochannels, which are in good agreement with MD simulations.