A stable discharge pressure of compressed hydrogen gas generated from the electrolysis of water is achieved and maintained at the outlet of a “hybrid” multistage compression system comprising at least a first section comprising at least one centrifugal compressor powered at least in part by electricity generated from at least one renewable energy source and a further section downstream of the first section, wherein the further section comprises at least one reciprocating compressor.

Operation of a multistage compression system comprising at least one centrifugal compressor having a dry gas seal with opposed seal faces, for compressing a gas feed having a variable flow rate is improved by operating the or at least one centrifugal compressor in a low power mode where the opposed faces of the dry gas seal are not in contact during periods when gas flow through the centrifugal compressor(s) is not sufficient for normal operation. Such operation not only reduces damage to the dry gas seals and hence improves reliability, but also reduces the overall power requirement of the overall compression system.

Operation of a multistage compression system comprising at least one centrifugal compressor having a dry gas seal with opposed seal faces, for compressing a gas feed having a variable flow rate is improved by operating the or at least one centrifugal compressor in a low power mode where the opposed faces of the dry gas seal are not in contact during periods when gas flow through the centrifugal compressor(s) is not sufficient for normal operation. Such operation not only reduces damage to the dry gas seals and hence improves reliability, but also reduces the overall power requirement of the overall compression system.

Energy efficiency and/or operational stability of a multistage compression system comprising a plurality (N) of centrifugal compressors that is compressing a gas feed having a variable flow rate is improved by adjusting reversibly the load on each compressor in response to changes in the flow rate of the gas feed using a main recycle system to enable operation of the centrifugal compressors at turndown capacity during periods when the flow rate is below total turndown capacity for all of the compressors, and if necessary, using the local recycle systems in order to avoid activation of anti-surge control, and switching one or more centrifugal compressors into low power mode or shutdown mode as required.

Energy efficiency and/or operational stability of a multistage compression system comprising a plurality (N) of centrifugal compressors that is compressing a gas feed having a variable flow rate is improved by adjusting reversibly the load on each compressor in response to changes in the flow rate of the gas feed using a main recycle system to enable operation of the centrifugal compressors at turndown capacity during periods when the flow rate is below total turndown capacity for all of the compressors, and if necessary, using the local recycle systems in order to avoid activation of anti-surge control, and switching one or more centrifugal compressors into low power mode or shutdown mode as required.

A centrifugal compressor includes: an impeller which is allowed to rotate around an axis; a casing which is provided with a return flow path allowing a fluid pressure-fed from the impeller to flow therein; and a return vane which is disposed inside the return flow path, wherein the return vane is provided with an injection port through which a liquid supplied from the outside is injected to the return flow path. Accordingly, power is further reduced while suppressing pressure loss.

Device and method for centrifugal compression of a working gas comprising a plurality of centrifugal compressors forming a plurality of compression stages and plurality of drive motors for driving the compressors, the device comprising a gas circuit comprising a first, inlet, pipe for the gas to be compressed, connected to an inlet of a first compressor, the circuit comprising a second pipe connected to an outlet of said first compressor, the second pipe being connected to an inlet of a second compressor, the circuit comprising at least one third, cooling, pipe having one end connected to the outlet of at least one of the compressors and at least one second end connected to an inlet of at least one motor for cooling thereof, the third, cooling, pipe comprising a first member for cooling the gas and two parallel branches respectively supplying two distinct motors of the device for their respective cooling.

Device and method for centrifugal compression of a working gas comprising a plurality of centrifugal compressors forming a plurality of compression stages and plurality of drive motors for driving the compressors, the device comprising a gas circuit comprising a first, inlet, pipe for the gas to be compressed, connected to an inlet of a first compressor, the circuit comprising a second pipe connected to an outlet of said first compressor, the second pipe being connected to an inlet of a second compressor, the circuit comprising at least one third, cooling, pipe having one end connected to the outlet of at least one of the compressors and at least one second end connected to an inlet of at least one motor for cooling thereof, the third, cooling, pipe comprising a first member for cooling the gas and two parallel branches respectively supplying two distinct motors of the device for their respective cooling.

A return geometry fluidically connects a first and a second compressor stage of the turbocompressor. The return geometry has multiple partial helices that are evenly or unevenly distributed in the circumferential direction. The multiple partial helices extend at least in part in the circumferential direction. They form flow channels that extend at least in some sections, separately from each other, to fluidically connect the first and second compressor stages.

A return geometry fluidically connects a first and a second compressor stage of the turbocompressor. The return geometry has multiple partial helices that are evenly or unevenly distributed in the circumferential direction. The multiple partial helices extend at least in part in the circumferential direction. They form flow channels that extend at least in some sections, separately from each other, to fluidically connect the first and second compressor stages.