Method for supplying gaseous nitrogen and liquefying nitrogen

A method for supplying gaseous nitrogen and liquefying nitrogen in which a flow of gaseous nitrogen is compressed in a compressor, wherein the method comprises a first mode of operation and a second mode of operation, wherein:

• according to the first mode of operation, the compressor compresses the flow of gaseous nitrogen from a first pressure to a second pressure, the first pressure being lower than the second pressure, and supplies the gaseous nitrogen at the second pressure as product, the compressor operating in parallel with at least one compressor of a group of at least two compressors that are connected in parallel receiving nitrogen at the first pressure and producing nitrogen at the second pressure;
• and
• according to the second mode of operation, the compressor no longer receives nitrogen at the first pressure but compresses a flow of gaseous nitrogen originating from the group of at least two compressors in parallel from the second pressure to a third pressure greater than the first pressure and the second pressure and supplies the gaseous nitrogen at the third pressure to a nitrogen liquefier in order to supply liquid nitrogen, the group of at least two compressors in parallel receiving nitrogen at the first pressure and compressing it to the second pressure.