Abstract: A compression train system and method for compressing air for an air separation unit is provided. The system includes at least one initial air compressor configured to receive and compress a flow of ambient pressure air and driven by a variable speed motor. The system further includes a plurality of downstream compressors or compression turbo-machines disposed in a series arrangement with the at least one initial compression stage. The desired flow rates to the compression system is controlled by adjusting the speed of the variable speed motor and the position of inlet guide vanes to increase or decrease the flow rate of the ambient pressure air and keep the speed of the variable speed motor above or below a restricted speed zone.

Abstract: A method and apparatus for producing and controlling flow rate of a compressed gas produced by a compression system having one or more stages of compression formed by a centrifugal compressor or compressors, inlet guide vanes to control flow through the compression stage or stages and an electric motor directly coupled to the stage or stages having a restricted speed zone within which vibrational modes can damage the electric motor. A desired flow rate is obtained by speed adjustment alone and with the inlet guide vanes positioned at 0° when the speed will lie above or below the restricted speed zone. Where a desired flow rate would require extended operation of the electric motor at a speed within the restricted speed zone, the speed is set to the uppermost level of the restricted speed zone and the desired flow rate is obtained through appropriate positioning of the inlet guide vanes.

Abstract: The present invention provides a method and apparatus of inhibiting a thrust bearing capacity of a compression system from being exceeded during a surge event in which a thrust bearing is biased with a biasing force to increase the thrust bearing overload margin between the capacity of thrust bearing to absorb axial forces and the greatest force produced during the surge event. This biasing force can be produced by appropriately sizing the high pressure seal on the side of the impeller opposite to the inlet of a compressor of the compression system so that the back disk force produced in the high pressure region of the high pressure seal and the low pressure region located inwardly of the high pressure region creates the desired bias force value and direction.

Abstract: The present invention provides a method and apparatus of inhibiting a thrust bearing capacity of a compression system from being exceeded during a surge event in which a thrust bearing is biased with a biasing force to increase the thrust bearing overload margin between the capacity of thrust bearing to absorb axial forces and the greatest force produced during the surge event. This biasing force can be produced by appropriately sizing the high pressure seal on the side of the impeller opposite to the inlet of a compressor of the compression system so that the back disk force produced in the high pressure region of the high pressure seal and the low pressure region located inwardly of the high pressure region creates the desired bias force value and direction.

Abstract: A method and apparatus for producing and controlling flow rate of a compressed gas produced by a compression system having one or more stages of compression formed by a centrifugal compressor or compressors, inlet guide vanes to control flow through the compression stage or stages and an electric motor directly coupled to the stage or stages having a restricted speed zone within which vibrational modes can damage the electric motor. A desired flow rate is obtained by speed adjustment alone and with the inlet guide vanes positioned at 0° when the speed will lie above or below the restricted speed zone. Where a desired flow rate would require extended operation of the electric motor at a speed within the restricted speed zone, the speed is set to the uppermost level of the restricted speed zone and the desired flow rate is obtained through appropriate positioning of the inlet guide vanes.

Abstract: The present invention provides a method and apparatus of inhibiting a thrust bearing capacity of a compression system from being exceeded during a surge event in which a thrust bearing is biased with a biasing force to increase the thrust bearing overload margin between the capacity of thrust bearing to absorb axial forces and the greatest force produced during the surge event. This biasing force can be produced by appropriately sizing the high pressure seal on the side of the impeller opposite to the inlet of a compressor of the compression system so that the back disk force produced in the high pressure region of the high pressure seal and the low pressure region located inwardly of the high pressure region creates the desired bias force value and direction.

Abstract: A compression method, a multistage compression system and an air separation method and plant in which a gas is compressed in a series of compression stages to produce a compressed gas and each of the compression stages incorporate a variable speed compressor. In such compression method and system, the compressed air is produced at a pressure that remains stable during both normal operational conditions and during turn down conditions during which the flow rate of the gas is reduced. This reduction is accomplished by reducing the speed of the compressor in an initial compression stage such that the compressor operates at a point along its peak efficiency operating line at which the pressure ratio is directly proportional to the flow rate and such that the lower turn down flow rate is obtained at a reduced pressure which is made up in successive compression stages.

Abstract: A compression method, a multistage compression system incorporating such method and an air separation method and plant utilizing such compression method and system in which a gas is compressed in a series of compression stages to produce a compressed gas and each of the compression stages incorporate a variable speed compressor. In such compression method and system, the compressed air is produced at a pressure that remains stable during both normal operational conditions and during turn down conditions during which the flow rate of the gas is reduced. This reduction is accomplished by reducing the speed of the compressor in an initial compression stage such that the compressor operates along a peak efficiency operating line at which the pressure ratio is directly proportional to the flow rate and such that the lower turn down flow rate is obtained at a reduced pressure which is made up in successive compression stages.

Abstract: A system for providing refrigeration to a heat load, especially over a larger temperature range and at a cryogenic temperature, wherein pulse tube refrigeration cools a heat transfer medium to provide higher level refrigeration to a refrigeration fluid, and lower level refrigeration is provided to the refrigeration fluid using a non-pulse tube system.

Abstract: A single column lower pressure cryogenic rectification system wherein nitrogen top vapor is condensed against column bottoms, elevated in pressure, and vaporized against elevated pressure fluid to achieve simultaneously high purity and high pressure nitrogen gas product.

Abstract: A heat exchanger constructed from a plurality of stacked modules, each module having closed channels for high pressure flow and fins extending vertically up and/or down from the channels which form open channels suitable for low pressure flow when the modules are stacked parallel along their length.