Station and process for dispensing a reduced-pressure gas

Process for dispensing a gas under a dispensing pressure, including the following steps:

• inlet of the gas under an inlet high pressure;
• reduction of the pressure of the inlet gas, from the inlet high pressure to a lower dispensing pressure;
• and
• dispensing of the a first fraction of the gas under the dispensing pressure;
• drawing off a complementary fraction of the inlet gas, before the pressure reduction;
• at least partial liquefaction of the complementary fraction, comprising exchange of heat with the reduced-pressure first fraction of the inlet gas, a first fraction of the gas being warmed by exchange with the complementary fraction of the gas to be liquefied;
• and
• collecting the liquefied complementary fraction.

A dispensing station for dispensing a gas at a dispensing pressure, comprising:

• a gas inlet for receiving gas at an inlet pressure;
• a gas dispenser for dispensing gas at a dispensing pressure lower than the inlet pressure;
• a pressure reducing machine for reducing a pressure of gas from the inlet pressure to the dispensing pressure while producing external work;
• a divider upstream of said pressure reducing machine for dividing gas from said gas inlet into a first fraction that is directed to an inlet of said pressure reducing machine and a complementary fraction;
• a countercurrent heat exchanger downstream of said divider in which heat is passed from the complementary fraction to the pressure-reduced first fraction, at least partially liquefying the complementary fraction of gas and concurrently heating the pressure-reduced first fraction;
• and
• a reservoir collecting the at least partially liquified complementary fraction,
• said countercurrent heat exchanger comprising a cooling passage with a hot end in communication with said gas inlet and a cold end in communication with said reservoir, a warming passage with a cold end in communication with an output from said pressure reducing machine and a hot end from which the heated pressure-reduced first fraction of gas is sent to said gas dispenser to be dispensed at the dispensing pressure, said divider connecting said cooling passage to the inlet of said pressure reducing machine.

A method of dispensing gas at a dispensing pressure, comprising the steps of:

• receiving gas at a gas inlet at an inlet pressure;
• dividing gas from the gas inlet into a first fraction and a complementary fraction;
• reducing a pressure of the first fraction of the gas from the inlet pressure to a dispensing pressure lower than the inlet pressure while producing external work;
• dispensing the reduced-pressure first fraction of the gas at the dispensing pressure from a gas dispenser;
• at least partially liquefying the complementary fraction of gas by passing heat to the reduced-pressure first fraction of gas in a countercurrent heat exchanger in which the reduced-pressure gas passes through a heating passage with a hot end from which the heated pressure-reduced first fraction of gas is sent to the gas dispenser to be dispensed at the dispensing pressure;
• and
• collecting the at least partially liquified complementary fraction from a cold end of a cooling passage in the countercurrent heat exchanger.