Adsorbed Natural Gas Storage for Vehicular Applications

The use of adsorbed natural gas (ANG) as a transportation fuel is a relatively cleaner alternative compared to that of gasoline and is important from the perspective of environmental safety. However, unlike gasoline and diesel, natural gas requires compression, liquefaction, and adsorption techniques for its storage, as it has a very low volumetric energy density. Among all storage techniques, adsorption-based natural gas (ANG) storage is considered as more economical and relatively safe technology due to its mild temperature and pressure conditions for the storage. This chapter will summarize the recent advances in the area of ANG with reference to various synthetic storage materials recently developed for the purpose and their efficiency towards storage and deliverability of natural gas. Particular emphasis will be given to adsorbents based on porous carbon materials, metal organic frameworks, and covalent organic frameworks for the said application. The synthetic procedure for the above adsorbents, followed by their efficiency to store and deliver natural gas, will be discussed. Finally, in the conclusion, the future scope of the technology will be summarized.

Heat and Mass Transfer in an Adsorbed Natural Gas Storage System Filled with Monolithic Carbon Adsorbent during Circulating Gas Charging

Adsorbed natural gas (ANG) technology is a promising alternative to traditional compressed (CNG) and liquefied (LNG) natural gas systems. Nevertheless, the energy efficiency and storage capacity of an ANG system strongly depends on the thermal management of its inner volume because of significant heat effects occurring during adsorption/desorption processes. In the present work, a prototype of a circulating charging system for an ANG storage tank filled with a monolithic nanoporous carbon adsorbent was studied experimentally under isobaric conditions (0.5–3.5 MPa) at a constant volumetric flow rate (8–18 m3/h) or flow mode (Reynolds number at the adsorber inlet from 100,000 to 220,000). The study of the thermal state of the monolithic adsorbent layer and internal heat exchange processes during the circulating charging of an adsorbed natural gas storage system was carried out. The correlation between the gas flow mode, the dynamic gas flow temperature, and the heat transfer coefficient between the gas and adsorbent was determined. A one-dimensional mathematical model of the circulating low-temperature charging process was developed, the results of which correspond to the experimental measurements.

Experimental study of the thermal management process at low-temperature circulating charging of an adsorbed natural gas storage system

Adsorbed natural gas (ANG) technology is a promising alternative to traditional compressed (CNG) and liquefied (LNG) natural gas systems. Nevertheless, energy efficiency and storage capacity of ANG system strongly depends on thermal management of its inner volume because of significant heat effects occurring during adsorption/desorption processes. At the same time low-temperature charging of ANG system provides its higher storage capacity as well as increased fire and explosion safety due to lower operating pressure and “bound-state” of gas molecules with the surface of adsorbent. In present work, a prototype of low-temperature circulating charging system for ANG storage tank filled with shaped microporous carbon adsorbent was studied experimentally in wide ranges of pressures (0.5-3.5 MPa) and gas flow rates (8-18 m3/h).

Experimental study of heat transfer in adsorbed natural gas storage system filled with microporous monolithic active carbon

The study of the thermal state of the monolithic adsorbent layer and internal heat exchange processes during the circulating charging of an adsorbed natural gas storage system was carried out. The correlation between gas flow mode and the heat transfer coefficient between gas and adsorbent is determined under conditions of mass transfer.