Hydrogen Storage Test-Bed: Physisorption of Hydrogen on Pelletized HighSurface Area Activated Carbon at Cryogenic Temperatures and ModeratePressures

摘要

Hydrogen storage on activated carbon at cryogenic temperatures (77K) and low pressure(2.75MPa) may be a viable alternative to compressed hydrogen or liquid hydrogen storagesystems in niche applications. The energy required to store the hydrogen is much less thanthat required to liquefy it, while the 5 to 6.5 kJ/mol heat of desorption may provide as much asa six-fold performance factor increase for boil-off and dormancy as compared to a liquidhydrogen system. At these temperatures and pressures, the volume of carbon is roughly 80%of the volume required for 35MPa compressed hydrogen. There are two main challenges thatneed to be addressed regarding this system. The first is to develop a control scheme to releasehydrogen at a rate compatible with a dynamic drive cycle of a fuel cell vehicle. This willdepend on the hydrogen diffusion rate through the bed of densified carbon and the rate of heatinput using an embedded resistive heater. The second is to investigate how fast the systemmay be filled with hydrogen. Introducing pre-cooled hydrogen gas and using the latent heat ofvaporization of the liquid nitrogen will provide cooling. The purpose of this test bed is tovalidate these claims based on the carbon performance, using a system designed to store ～200 gof hydrogen. System details and test procedures are discussed in this paper; results will bepresented at the conference.