Abstract: A system stores densely dissolved methane-base gas and supplies gas of a predetermined composition. A container (10) stores methane-base gas dissolved in hydrocarbon solvent and supplies it to means for adjusting composition, through which an object of regulated contents is obtained. Preferably, the means for adjusting composition is means for maintaining the tank in a supercritical state, or piping (48) for extracting substances at a predetermined ratio from the gas phase (12) and liquid phase (16) in the container.

Abstract: A system stores densely dissolved methane-base gas and supplies gas of a predetermined composition. A container (10) stores methane-base gas dissolved in hydrocarbon solvent and supplies it to means for adjusting composition, through which an object of regulated contents is obtained. Preferably, the means for adjusting composition is means for maintaining the tank in a supercritical state, or piping (48) for extracting substances at a predetermined ratio from the gas phase (12) and liquid phase (16) in the container.

Abstract: A method and apparatus of treating the BOG generated in low temperature liquid storage tanks are described, wherein the BOG is strongly adsorbed to and stored in a porous material by contacting the BOG with the porous material in the presence of a compound serving as a host.

Abstract: A method of storing and transporting gas wherein a large amount of gas is stored and transported by bringing the gas into contact with a porous material having fine pores and a large specific surface area in the presence of a compound serving as a host at or close to room temperature. The method according to the invention enables the gas in an amount equivalent to more than 180 times as much as an unit volume of the porous material to be stored or transported in a short time, even under a low pressure, for example, atmospheric pressure or up to 10.68 atm (equivalent to 10 kg/cm.sup.2 by gauge pressure) or less, and furthermore, is applicable to various kinds of gases.