Method of feeding, with impure nitrogen, the combustion chamber of a gas turbine combined with an air distillation unit, and corresponding electricity generation plant

Method of feeding, with impure nitrogen, a combustion chamber of a gas turbine combined with an air distillation unit, the air distillation unit being equipped with an apparatus for purifying air of water and of CO2 by adsorption, said apparatus comprising two adsorbers, each one of which follows an operating cycle which comprises, alternately and cyclically, a co-current adsorption phase at a high pressure of the cycle, and a regeneration phase, the regeneration phase comprising a decompression step (a), a step (c) of counter-current purging by waste gas from the air distillation unit coming from a low-pressure column of this unit, and a step (d) of recompressing the adsorber up to the high pressure of the cycle, wherein:

• the low-pressure column operates at a low pressure which is clearly greater than atmospheric pressure;
• the waste gas is used almost at said low pressure for the purging step (c);
• the decompression step (a) is continued down to a minimum pressure of the cycle which is clearly less than said low pressure;
• between the decompression step (a) and the purging step (c), a partial repressurization step (b) is inserted, in which the adsorber is repressurized with waste gas up to almost the purging pressure;
• and
• the waste gas coming from the adsorber during the purging step (c) is mixed with the waste gas produced by the air distillation unit, and the mixture is compressed by a nitrogen compressor in order to feed the combustion chamber of the gas turbine.