A distillation column system and a plant are for production of oxygen by cryogenic fractionation of air. The distillation column system has a high-pressure column and a low-pressure column, a main condenser, and an argon column with an argon column top condenser. The low-pressure column comprises an upper mass transfer region, a lower mass transfer region and a middle mass transfer region. The argon column top condenser is arranged within the low-pressure column between the upper and middle mass transfer regions and is configured as a forced-flow evaporator.

A system for removing nitrogen from a natural gas fluid feed stream includes a main heat exchanger that receives the natural gas fluid feed stream. A distillation column receives a cooled fluid stream from the main heat exchanger and features a return vapor outlet and a side vapor outlet port, The return vapor outlet provides nitrogen vapor to the main heat exchanger which is warmed therein. The side vapor outlet port provides vapor to the main heat exchanger and a reflux compressor receives and compresses the resulting fluid from the main heat exchanger. A reflux aftercooler receives and cools fluid from the reflux compressor, directs cooled fluid to the main heat exchanger and the resulting fluid is directed to a reflux separation device. The reflux separation device has a vapor outlet and a liquid outlet. The vapor outlet of the reflux separation device directs fluid to the main heat exchanger so that fluid is directed to the first reflux inlet port of the distillation column. The liquid outlet of the reflux separation device directs fluid to a second reflux inlet port of the distillation column.

A heat exchanger system includes a core-in-shell heat exchanger and a liquid/gas separator. The liquid/gas separator is configured to receive a liquid/gas mixture and to separate the gas from the liquid. The liquid/gas separator is connected to the core-in-shell heat exchanger via a first line for transmitting gas from the liquid/gas separator to a first region in the core-in-shell heat exchanger and connected to the core-in-shell heat exchanger via a second line for transmitting liquid from the liquid/gas separator to a second region of the core-in-shell heat exchanger

A heat exchanger with plates defining a first series of passages for channeling at least one refrigerant fluid and a second series of passages for channeling at least one calorigenic fluid, at least one passage of the first series being defined between a first plate defining an adjacent passage of the second series and a second plate. A mixing device is arranged in the passage of the first series and includes a first surface arranged facing the first plate and a second surface arranged facing the second plate, at least one first channel for channeling a gas phase of the refrigerant fluid, and at least one second channel for channeling a liquid phase of the refrigerant fluid.

Embodiments of the present invention relate to a refrigeration method, during which a user is supplied with frigories by means of a working gas, such as helium, that is cooled by having the same flow into a cold box that comprises, in series, at least one first aluminum heat exchanger having brazed plates and flanges, one second heat exchanger having welded plates, and one third aluminum heat exchanger having brazed plates and flanges in such a way that the flow of said working gas is at least partially caused to pass, consecutively, through the first exchanger, then through the second exchanger, and finally through the third exchanger before said working gas flow is directed to the user in order to supply the user with frigories.

A device for refrigerating and/or liquefying a working gas comprising helium, the device comprising a looped working circuit for the working gas includes, in series, a compression station, a cold box, a heat exchange system exchanging heat between the cooled working gas and a user, the device further comprising an additional pre-cooling system comprising at least one tank of auxiliary cryogenic fluid, such as liquid nitrogen, the cold box comprising a first cooling stage of the working gas comprising a first exchanger disposed at the output of the compression station as well as a second heat exchanger and a third heat exchanger, the first heat exchanger being of the aluminum plate-fin type, the second heat exchanger being of the tube or welded plate type, characterized in that the second and third heat exchangers are connected both serially and in parallel on the working circuit downstream of the first heat exchanger.

A method for obtaining an air product in an air separating system in which a liquid fraction is obtained from feed air and used to provide the air product and in which the liquid fraction is temporarily stored in a tank arrangement. A tank arrangement with at least two tanks is used, and the liquid fraction is fed to at least one of the tanks and/or is removed from at least one of the tanks in order to provide the air product. In the process, the liquid fraction is not fed to and removed from any one of the tanks at the same time, and the composition of the liquid fraction in a tank is ascertained prior to each removal of the liquid fraction from the tank. An air separating system is also described.

A method for compression of an incoming feed air stream using at least two variable speed compressor drive assemblies controlled in tandem is provided. The first variable speed drive assembly drives at least one compression stage in the lower pressure compressor unit driven while the second variable speed drive assembly drives higher pressure compression stage disposed either in the common air compression train or the split functional compression train of the air separation plant. The first and second variable speed drive assemblies are preferably high speed, variable speed electric motor assemblies each having a motor body, a motor housing, and a motor shaft with one or more impellers directly and rigidly coupled to the motor shaft via a sacrificial rigid shaft coupling.

A method for compression of an incoming feed air stream using at least two variable speed compressor drive assemblies controlled in tandem is provided. The first variable speed drive assembly drives at least one compression stage in the lower pressure compressor unit driven while the second variable speed drive assembly drives higher pressure compression stage disposed either in the common air compression train or the split functional compression train of the air separation plant. The first and second variable speed drive assemblies are preferably high speed, variable speed electric motor assemblies each having a motor body, a motor housing, and a motor shaft with one or more impellers directly and rigidly coupled to the motor shaft via a sacrificial rigid shaft coupling.

A method for compression of an incoming feed air stream using at least two variable speed compressor drive assemblies controlled in tandem is provided. The first variable speed drive assembly drives at least one compression stage in the lower pressure compressor unit driven while the second variable speed drive assembly drives higher pressure compression stage disposed either in the common air compression train or the split functional compression train of the air separation plant. The first and second variable speed drive assemblies are preferably high speed, variable speed electric motor assemblies each having a motor body, a motor housing, and a motor shaft with one or more impellers directly and rigidly coupled to the motor shaft via a sacrificial rigid shaft coupling.