Thermal enhancement of charge and discharge cycles for adsorbed natural gas storage

The usage of adsorbed natural gas (ANG) storage is hindered by the thermal management during the adsorption and desorption processes. An effective thermal enhancement is thus essential for the development of the ANG technology and the motivation for this study is the investigation of a gas storage system with internal thermal control. We employed a fin-tube type heat exchanger that is placed in a pressurized cylinder. A distributed-parameter model is used for the theoretical modeling and simulations are conducted at assorted charging and discharging conditions. These studies included the transient thermal behaviours of the elements within the ANG-charged cylinder and parameters such as pressure and temperature profiles of adsorbent have been obtained during charge and discharge cycles, and results are compared with a conventional compressed methane vessel.

Highlights
► An method of storing methane gas at low pressure and ambient temperature is demonstrated where the gas is adsorbed or desorbed into the mesoporous cavities of activated carbon.
► This innovative methane storage is conducted only at one-tenth of the pressures used in the compressed natural gas (CNG) but it could attain a volume to volume ratio twice that of CNG. The charging and discharging rates are examined by a depressurization procedure.
► A mathematical model that describes the charging and discharging processes has been verified experimentally.