Abstract: A method for operating start-up of a compressor train is disclosed. The train includes a driver machine and at least a centrifugal compressor drivingly coupled to the driver machine. The centrifugal compressor in turn includes a plurality of compressor stages and at least a first set of variable inlet guide vanes at an inlet of one of the compressor stages. The method includes at least partly closing the first set of variable inlet guide vanes; when the first set of variable inlet guide vanes is at least partly closed, starting rotation of the centrifugal compressor and accelerating the centrifugal compressor up to a minimum operating speed; opening the at least one set of variable inlet guide vanes to increase the gas flow through the centrifugal compressor once the minimum operating speed has been achieved.

Abstract: A compressor system is disclosed, including a first compressor unit having: at least a first gas inlet at a first gas pressure level; a second gas inlet at a second gas pressure level; and a gas discharge; a second compressor unit having: at least a third gas inlet at a third gas pressure level; a fourth gas inlet at a fourth gas pressure level; and a gas delivery. The gas discharge of the first compressor unit is fluidly coupled to one of the third gas inlet and fourth gas inlet of the second compressor unit.

Abstract: A method for starting and operating a plant for the liquefaction of a gaseous product comprising the steps of electrically connecting a variable frequency drive to a motor of a first machine string; increasing the speed of the motor of the first machine string up until a first predefined threshold; electrically disconnecting the variable frequency drive from the motor of the first machine string; electrically connecting the variable frequency drive to a motor of a second machine string; the first predefined threshold is function of said frequency of the power supply grid. The variable frequency drive can be switched during operation of the plant among the strings according to process requirements.

Abstract: A method is described for providing antisurge control in a system comprising a compressor having at least an upstream compressor stage, a downstream compressor stage and a side stream bringing flow into a flow passage between the upstream compressor stage and the downstream compressor stage. The method provides for estimating a temperature of a flow delivered by the upstream compressor stage using a non-dimensional performance map of the upstream compressor stage and further estimating a temperature of a flow entering the downstream compressor stage based on the mass flow and flow temperature of the flow delivered by the downstream compressor stage and the mass flow and the flow temperature of the side stream. The method further provides for performing antisurge control of the downstream compressor stage based on the temperature of the flow entering the downstream compressor stage.

Abstract: An LNG refrigerant compressor train (1) is disclosed. The train comprises: a driver section (11), drivingly coupled to a compressor section (13) through a shaft line (1). The compressor section is comprised of at least one refrigerant fluid compressor, driven into rotation by the driver section (11).

Abstract: The method is used for uniforming temperature in a shaft supported by a fluid bearing during rotation of the shaft; a journal portion of the shaft is located inside the fluid bearing; at least one passage is provided inside the shaft at least along the journal portion so to cross it; at least one flow of heat-exchange fluid is established in the at least one passage; the method allows to overcome the problems due to the “Morton effect”. A bearing system implementing the method is advantageously used in a turbomachine.

Abstract: The compression train includes an engine, a first centrifugal compressor driven by the engine and a second centrifugal compressor driven by the engine; the first centrifugal compressor is housed inside one case; the second centrifugal compressor is housed inside one case; the first centrifugal compressor has a first inlet fluidly connected to a line of high molecular weight gas, in particular higher than 40; the second centrifugal compressor has a second inlet fluidly connected to a line of low molecular weight gas, in particular between 20 and 30; the second centrifugal compressor is arranged to provide a compression ratio higher than 10:1.

Abstract: The ammonia production plant includes a feed gas compression section, a process air compression section, a syngas compression section and a refrigerant compression section. At least two of these compression sections are combined together forming a combined compression train driven by a single driver.

Abstract: A compressor system is disclosed, including a first compressor unit having: at least a first gas inlet at a first gas pressure level; a second gas inlet at a second gas pressure level; and a gas discharge; a second compressor unit having: at least a third gas inlet at a third gas pressure level; a fourth gas inlet at a fourth gas pressure level; and a gas delivery. The gas discharge of the first compressor unit is fluidly coupled to one of the third gas inlet and fourth gas inlet of the second compressor unit.

Abstract: According to one aspect of the present disclosure, a natural gas liquefaction system (100) is provided. The system comprises an integrally-geared turbo-compressor (150) with a plurality of compressor stages; a prime mover (160) for driving the compressor; a pre-cooling loop (110), through which a first refrigerant is adapted to circulate, wherein one or more first compressor stages (151) of the plurality of compressor stages are adapted to pressurize the first refrigerant; a cooling loop (130), through which a second refrigerant is adapted to circulate, wherein one or more second compressor stages (155) of the plurality of compressor stages are adapted to pressurize the second refrigerant; a first heat exchanger device (170) for transferring heat from a natural gas and/or from the second refrigerant to the first refrigerant; and a second heat exchanger device (180) for transferring heat from the natural gas to the second refrigerant.

Abstract: The ammonia production plant includes a feed gas compression section, a process air compression section, a syngas compression section and a refrigerant compression section. At least two of these compression sections are combined together forming a combined compression train driven by a single driver.

Abstract: A method for operating start-up of a compressor train is disclosed. The train includes a driver machine and at least a centrifugal compressor drivingly coupled to the driver machine. The centrifugal compressor in turn includes a plurality of compressor stages and at least a first set of variable inlet guide vanes at an inlet of one of the compressor stages. The method includes at least partly closing the first set of variable inlet guide vanes; when the first set of variable inlet guide vanes is at least partly closed, starting rotation of the centrifugal compressor and accelerating the centrifugal compressor up to a minimum operating speed; opening the at least one set of variable inlet guide vanes to increase the gas flow through the centrifugal compressor once the minimum operating speed has been achieved.

Abstract: A drive system for driving at least one compressor is described. The system comprises a gas turbine configured and arranged for driving the compressor. The gas turbine has a hot end and a cold end. A load coupling for connection of said gas turbine to the compressor is arranged at hot end of the gas turbine. An electric motor/generator arranged at the cold end of the gas turbine. The electric motor/generator is electrically connected to an electric power grid and is adapted to function as a generator for converting excess mechanical power from the gas turbine into electrical power and delivering the electrical power to the electric power grid, and as a motor for supplementing driving power to the compressor.

Abstract: The method is used for uniforming temperature in a shaft supported by a fluid bearing during rotation of the shaft; a journal portion of the shaft is located inside the fluid bearing; at least one passage is provided inside the shaft at least along the journal portion so to cross it; at least one flow of heat-exchange fluid is established in the at least one passage; the method allows to overcome the problems due to the “Morton effect”. A bearing system implementing the method is advantageously used in a turbomachine.

Abstract: A method for starting and operating a plant for the liquefaction of a gaseous product comprising the steps of electrically connecting a variable frequency drive to a motor of a first machine string; increasing the speed of the motor of the first machine string up until a first predefined threshold; electrically disconnecting the variable frequency drive from the motor of the first machine string; electrically connecting the variable frequency drive to a motor of a second machine string; the first predefined threshold is function of said frequency of the power supply grid. The variable frequency drive can be switched during operation of the plant among the strings according to process requirements.

Abstract: A device for sealing a high pressure region in a turbomachine from a low pressure region; the turbomachine has one or more statoric parts and one or more rotoric parts; the device comprises a labyrinth seal having a first plurality of grooves and a second plurality of grooves; the first plurality of grooves is disposed in a helical pattern and the second plurality of grooves is disposed in a cylindrical pattern; the labyrinth seal is disposed between at least one of the one or more rotoric parts of the turbomachine and at least one of the one or more statoric parts of the turbomachine between the high pressure region and the low pressure region of the turbomachine; the helical pattern has a helix angle less than or equal to 10°, wherein a stabilization effect of the turbomachine is obtained and leakage due to the second plurality of grooves is negligible.

Abstract: A natural gas liquefaction system is disclosed, which comprises at least a pre-cooling loop, through which a first refrigerant is adapted to circulate. The pre-cooling loop comprises at least one compressor for pressurizing the first refrigerant; at least one prime mover for driving the compressor; at least one condenser for removing heat from the first refrigerant; at least a first expansion element for expanding the first refrigerant; at least a first heat exchanger for transferring heat from natural gas to the first refrigerant. The system further comprises at least a cooling loop, downstream of the pre-cooling loop, where through a second refrigerant circulates. The natural gas is adapted to be sequentially cooled in the pre-cooling loop and in the cooling loop. The compressor of the pre-cooling loop is an integrally-geared turbo-compressor comprising a plurality of compressor stages.

Abstract: A method is described for providing antisurge control in a system comprising a compressor having at least an upstream compressor stage, a downstream compressor stage and a side stream bringing flow into a flow passage between the upstream compressor stage and the downstream compressor stage. The method provides for estimating a temperature of a flow delivered by the upstream compressor stage using a non-dimensional performance map of the upstream compressor stage and further estimating a temperature of a flow entering the downstream compressor stage based on the mass flow and flow temperature of the flow delivered by the downstream compressor stage and the mass flow and the flow temperature of the side stream. The method further provides for performing antisurge control of the downstream compressor stage based on the temperature of the flow entering the downstream compressor stage.

Abstract: A drive system for driving at least one compressor is described. The system comprises a gas turbine configured and arranged for driving the compressor. The gas turbine has a hot end and a cold end. A load coupling for connection of said gas turbine to the compressor is arranged at hot end of the gas turbine. An electric motor/generator arranged at the cold end of the gas turbine. The electric motor/generator is electrically connected to an electric power grid and is adapted to function as a generator for converting excess mechanical power from the gas turbine into electrical power and delivering the electrical power to the electric power grid, and as a motor for supplementing driving power to the compressor.

Abstract: A device for sealing a high pressure region in a turbomachine from a low pressure region; the turbomachine has one or more statoric parts and one or more rotoric parts; the device comprises a labyrinth seal having a first plurality of grooves and a second plurality of grooves; the first plurality of grooves is disposed in a helical pattern and the second plurality of grooves is disposed in a cylindrical pattern; the labyrinth seal is disposed between at least one of the one or more rotoric parts of the turbomachine and at least one of the one or more statoric parts of the turbomachine between the high pressure region and the low pressure region of the turbomachine; the helical pattern has a helix angle less than or equal to 10°, wherein a stabilization effect of the turbomachine is obtained and leakage due to the second plurality of grooves is negligible.