| 초록 |
Methane delivery capacity in MOF-74 series was investigated for adsorbed natural gas vehicles applications. Specially, density functional theory was used to derive force field parameters for the grand canonical Monte Carlo simulations to predict the methane adsorption properties. Our results show that generally used DFT exchange correlation functionals (e.g. PBE+D2, vdW-DF2) overestimated binding energy of methane to the MOF-74 series, occurring inaccurate description of the adsorption capacities. The global scaling factor of PBE+D2 exchange correlation functional was optimized to find an apt functional that lead to good agreement with experimental adsorption data for methane. Our computational results using the newly derived force field parameters predict a methane uptake of 279 cm3/cm3 in V-MOF-74 at T= 298K and P= 65 bar, which would be higher than the current record holder (HKUST-1, 270 cm3/cm3). Although the working capacity is low due to the strong binding energy of methane with V-MOF-74, modifying the process conditions (e.g. lower desorption pressure, higher desorption temperature) can improve the methane working capacity, near to the DOE requirement for the ANG technology. |
