A new method boosts the natural gas storage capacity of porous adsorbent materials, such as zeolites (Nano Lett. 2016, DOI: 10.1021/acs.nanolett.6b00919). The advance could lead to a compact, lightweight, and low-cost technology for storing natural gas as a vehicle fuel.
Moises A. Carreon of Colorado School of Mines, Shiguang Li of the Gas Technology Institute, Miao Yu of the University of South Carolina, and colleagues first coated commercially available zeolite beads with amorphous silica and then alumina, which reduced the material’s pore sizes to between 1.34 and 1.42 nm. Then the researchers injected the main component of natural gas, methane, at high pressure (5 megapascals) into a tank containing the beads. Once the beads had fully adsorbed the methane, the researchers exposed them to 2,2-dimethylbutane vapor, which entered the pores and sealed them, effectively turning the beads into tiny gas tanks. The researchers could then store the beads at 0.1 MPa, close to atmospheric pressure. The coated beads stored twice the amount of methane as uncoated beads.
To release the methane, the researchers heated the beads slowly up to 150–200 °C to gradually drive off the sealant from the pores.
Haiqing Lin of the University at Buffalo, SUNY, says that using this method with advanced porous materials, such as metal-organic frameworks, could meet storage targets set by the Advanced Research Projects Agency-Energy for natural gas sorbents.