Gas treatment process comprising: - providing a leaktight and thermally insulating tank comprising an internal space filled with gas in a liquid-vapour two-phase state of equilibrium; - providing a heat exchanger intended to transfer cold from a vapour-phase gas stream collected in the tank to a fluid to be cooled; the heat exchanger comprising a first channel and a second channel each having an inlet (13a, 14a) and an outlet (13b, 14b) and heat exchange walls for transferring heat from the second channel to the first channel; and - extracting vapour-phase gas from the tank via an admission pipe which passes through an aperture made in a wall of the tank and emerges in the internal space of the tank during a tank loading operation and conveying it through a first pipe to a manifold (11, 47) which is connected to a gas storage terminal; and - extracting vapour-phase gas from the tank via the admission pipe during a tank utilizing operation and conveying it to the heat exchanger through a second pipe which is heat-insulated and has a gas passage cross section that is smaller than that of the first pipe, the gas treatment process further comprising: - providing a compressor which is connected upstream to the outlet of the first channel of the heat exchanger so as to compress the gas stream heated in the heat exchanger and is connected downstream to a three-way connector (17, 18) that is capable of conveying a first portion of the gas stream to a gas-consuming member (23, 24, 25) and of conveying a second portion of the gas stream to the inlet of the second channel of the heat exchanger in order to cool the second portion of the gas stream; and - providing an expansion device that is connected upstream to the outlet of the second channel of the heat exchanger and is connected downstream to a return circuit leading to the tank; the expansion device being arranged to depressurize the second portion of the gas stream originating from the second channel of the heat exchanger so as to liquefy it; - determining a set flow-rate of the gas-consuming member (23, 24, 25) during the tank utilizing operation; - comparing the set flow rate with a determined threshold; - extracting vapour-phase gas from the tank via the admission pipe and conveying it through the first pipe to the heat exchanger when the set flow rate is greater or equal to the determined threshold; and - extracting vapour-phase gas from the tank via the admission pipe and conveying it through the second pipe to the heat exchanger when the set flow rate is lower than the determined threshold. - providing a leaktight and thermally insulating tank comprising an internal space filled with gas in a liquid-vapour two-phase state of equilibrium; - providing a heat exchanger intended to transfer cold from a vapour-phase gas stream collected in the tank to a fluid to be cooled; the heat exchanger comprising a first channel and a second channel each having an inlet (13a, 14a) and an outlet (13b, 14b) and heat exchange walls for transferring heat from the second channel to the first channel; and - extracting vapour-phase gas from the tank via an admission pipe which passes through an aperture made in a wall of the tank and emerges in the internal space of the tank during a tank loading operation and conveying it through a first pipe to a manifold (11, 47) which is connected to a gas storage terminal; and - extracting vapour-phase gas from the tank via the admission pipe during a tank utilizing operation and conveying it to the heat exchanger through a second pipe which is heat-insulated and has a gas passage cross section that is smaller than that of the first pipe, the gas treatment process further comprising: - providing a compressor which is connected upstream to the outlet of the first channel of the heat exchanger so as to compress the gas stream heated in the heat exchanger and is connected downstream to a three-way connector (17, 18) that is capable of conveying a first portion of the gas stream to a gas-consuming member (23, 24, 25) and of conveying a second portion of the gas stream to the inlet of the second channel of the heat exchanger in order to cool the second portion of the gas stream; and - providing an expansion device that is connected upstream to the outlet of the second channel of the heat exchanger and is connected downstream to a return circuit leading to the tank; the expansion device being arranged to depressurize the second portion of the gas stream originating from the second channel of the heat exchanger so as to liquefy it; - determining a set flow-rate of the gas-consuming member (23, 24, 25) during the tank utilizing operation; - comparing the set flow rate with a determined threshold; - extracting vapour-phase gas from the tank via the admission pipe and conveying it through the first pipe to the heat exchanger when the set flow rate is greater or equal to the determined threshold; and - extracting vapour-phase gas from the tank via the admission pipe and conveying it through the second pipe to the heat exchanger when the set flow rate is lower than the determined threshold.