Can it be compressed to a liquid economically? Like propane or butane?
LNG is a great potential fuel, but not easily made a liquid. High pressure required.
LNG is stored at low pressure, nearly atmospheric pressure when compared to CNG, Compressed Natural Gas.
LNG is created by cooling methane (natural gas) down to -260 °F, not compressing. It cannot be compressed to a liquid at ambient temperature, that is far above the critical temperature point.
Can it be compressed to a liquid economically?
It can be compressed to liquid economically relative to the price of ethane. It needs to be compressed to ~550 psi to become liquid. Although the compression generates significant heat which requires cooling before economic storage, it does not require cooling to remain liquid, unlike LNG.