CNG carrier

Compressed natural gas (CNG) carrier ships are designed for transportation of natural gas under high pressure. CNG carrier technology relies on high pressure, typically over 200 bar (2900 psi), to increase the density of the gas. Full scale CNG carriers are under development. Whether CNG carriers may find their place in competition with the well established technology of liquefied natural gas by LNG carriers in yet to be demonstrated.

Pressure container technology
Several approaches to the problem of a cost-effective high-pressure containers. The main variables are the material to be used and the geometry of the containers. Standard method of storing non-condensed gases in metal flasks is not cost-effective for high-volume storage at high pressure. (This does not apply to gases such as butane and propane or their mixtures as in liquefied petroleum gas (LPG). LPG gases liquefy at ambient temperatures under moderate pressure and can be economically stored in steel containers of various sizes.)

New approaches to CNG technology include fiber-reinforced plastic containers and containers in the form of metal tubes of moderate diameter (typically 6" or 168 mm internal diameter). In one approach (Coselle) 17 km of tubing is wound on a spindle. Such spindles are stackable and may be connected to achieve the desired capacity.