Using grand canonical Monte Carlo (GCMC) simulations, we studied whether the new DOE targets for on-board methane storage can be attained if heat of adsorption at low loading (Qst°) is increased in eight representative metal-organic frameworks (MOFs) with varied pore volumes and surface areas. Because the deliverable capacity is more relevant to practical applications, we focus our discussions on the volumetric and gravimetric deliverable capacities. We found that the optimal Qst° for maximum CH4 delivery is approximately 20 kJ/mol. However, the new DOE targets are difficult to achieve in terms of the deliverable capacities, even after increasing Qst°. When the storage and discharge pressures are 65 and 1 bar, respectively, the volumetric and gravimetric targets can be attained under special combinations of pore volume and Qst°. Our results suggest that storing and delivering CH4 at lower temperatures could be considered to attain the new targets using current technologies, although it would result in some additional cost.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films