Natural gas currently is gaining a worldwide acceptance as an economical
fuel for vehicles and other applications. Even from the environmental
point of view, natural gas performs better than gasoline and diesel.
However, the storage of natural gas is considered one of the major bottlenecks
toward its widespread application. The adsorptive storage of
natural gas (ANG) is a promising alternative to the traditional, expensive
storage by compression [i.e., compressed natural gas (CNG)]. However,
ANG suffers from many techno-economic problems. In many countries
(e.g., USA, China), a large effort has been made toward the replacement
of high-pressure compression by an alternative method of storage suitable
for working at pressures up to 500 psi (3.4 MPa). This upper limit of
pressure easily can be achieved with a single-stage compressor. Alternatively,
the vehicle can be refueled directly from a high-pressure natural
gas pipeline. In this way, a significant decrease in the capital and operating
costs of compression stations can be achieved. Due to its relatively
low pressure, ANG obviously has some advantages according to weight,
shape, safety, and costs of the storage vessel. In the future, ceramic adsorbent
materials such as silica gel, activated alumina, zeolite, or silicon
carbide may play an important role in ANG technology. In this review, a
comparison of activated carbon as a traditional adsorbent as well as new
ceramic adsorbents is discussed for the storage of natural gas. |
