Design and validation of Clathrate-CNT systems for solid state hydrogen storage

Solid state hydrogen storage addresses the problems of high pressurization in compressed gaseous state and energy intensive liquefaction in liquid state. Clathrate structures have shown promising results as host material for storing hydrogen as hydrate. The effect of different promoters on improving storage capabilities of clathrates have been studied at 263 K and 10 MPa hydrogen pressure. Hydrogen adsorption kinetics of four different clathrates using promoters Tetrahydrofuran, Tetrahydropyran, 1,3 Dioxolane and 2,3 Dihydrofuran with Multiwall Carbon nanotube as substrate was carried out. The results showed ∼1.5 wt% hydrogen adsorption within 90 min using CNT substrate. This is one of the first reports on usage of CNT as a substrate material for hydrogen storage in clathrate systems. It was observed that CNT shows synergitic effect in the hydrogen adsorption with fast kinetics (less than 90 min). The weight of substrate material (CNT) was also taken into consideration while calculating the weight % of hydrogen adsorption. The present study also involves design and simulation of a hydrogen storage canister (using CNT based clathrate) with embedded helical coolant coils on COMSOL Multiphysics software to analyse the effects of temperature management on improving hydrogen storage capability of the clathrate reactor bed. Results of simulation includes variation of hydrate concentration and temperature in clathrate reactor bed with the passage of time. The theoretical studies pave way for validating the scalability of clatharates as a viable hydrogen energy system.