A process for the production of a liquid oxygen stream and a liquid hydrocarbon-rich stream by the cryogenic rectification of an inlet air stream, including dividing the inlet air stream into a first portion, and a second portion. Cooling the first portion, and the second portion against a cooled multicomponent refrigerant circuit, thereby producing a first cooled portion, and a second cooled portion. Condensing the first cooled portion, thereby producing a condensed first portion, then introducing the condensed first portion into one or more distillation columns. Expanding the second cooled portion in a turbo-expander, thereby producing an expanded second portion, then introducing the expanded second portion within the one or more distillation columns. Producing within the one or more distillation columns at least a waste nitrogen stream, a nitrogen enriched stream, and an oxygen enriched stream.

A process for the production of a liquid oxygen stream by the cryogenic rectification of an inlet air stream, including dividing the inlet air stream into a first portion, and a second portion. Cooling the first portion, and the second portion against a cooled multicomponent refrigerant circuit, thereby producing a first cooled portion, and a second cooled portion. Condensing the first cooled portion, thereby producing a condensed first portion, then introducing the condensed first portion into one or more distillation columns. Expanding the second cooled portion in a turbo-expander, thereby producing an expanded second portion, then introducing the expanded second portion within the one or more distillation columns. Producing within the one or more distillation columns at least a waste nitrogen stream, a nitrogen enriched stream, and an oxygen enriched stream. Withdrawing the oxygen enriched stream from the one or more distillation columns as a liquid oxygen stream.

A nitrogen producing cryogenic air separation unit with an excess air circuit is provided. The nitrogen producing cryogenic air separation unit is capable of producing high pressure gaseous nitrogen without the use of a nitrogen product compressors and is also capable of producing high rates of liquid nitrogen without adding additional compression stages in the main air compressor and/or without a nitrogen recycle compressor.

According to the present invention, a method for cryogenic separation of air using an air separation unit comprising a rectification column is provided. Feed air is compressed, cooled and rectified in the rectification column obtaining an overhead gas, wherein a part of the overhead gas of the rectification column is condensed using fluid withdrawn from the rectification column, wherein the condensed overhead gas is used at least in part as a liquid reflux to the rectification column, wherein a first part of the fluid which is used for cooling the overhead gas of the rectification column is, after its use for cooling, compressed and reintroduced into the rectification column, and wherein a second part of the fluid which is used for cooling the overhead gas of the rectification column is, after its use for cooling, expanded and withdrawn from the air separation unit.

A method for alarm monitoring abnormal conditions associated with a process operation includes collecting N sample data representing one or more parameters of a process, determining a distribution type of the sample data, obtaining an alarm monitoring strategy associated with the distribution type, and monitoring the process using the alarm monitoring strategy. The distribution type may be single-constant, multi-level discrete, normally distributed, continuous non-normally distributed, cyclical trend-up/down, and drifting away after a period maintenance. The alarm monitoring strategy includes a unilateral or bilateral control chart. The one-side control chart has either an upper control limit (UCL) of (100−p) or a lower control limit (LCL) of (p), and the two-sided control chart has a UCL of (100−p/2) and an LCL of (p/2), where p is a predetermined false alarm rate which determines the number N. The control limit may be a difference between two adjacent sample values of the sample data.

A set of process equipment for use in an enhanced oil recovery (EOR) process comprises first piping, a dehydrator, second piping, and a natural gas liquids recovery column. The first piping is configured to receive a wet carbon dioxide recycle stream from a recovery well. The dehydrator is configured to receive the wet carbon dioxide stream from the first piping and configured to dehydrate the wet carbon dioxide recycle stream using ethylene glycol to produce a dry carbon dioxide recycle stream. The second piping is configured to receive the dry carbon dioxide recycle stream from the dehydrator. The natural gas liquids recovery column is configured to receive the dry carbon dioxide recycle stream from the second piping and configured to separate the dry carbon dioxide recycle stream into a carbon dioxide reinjection stream and a natural gas liquids stream.

A portion of feed air is expanded and cooled in front of a main heat exchanger, and is used as cold for precooling the remaining unexpanded feed air inside the main heat exchanger. A portion of the feed air precooled inside the main heat exchanger is removed to outside the main heat exchanger, expanded and cooled, and used as cold to cool the remaining unexpanded precooled feed air inside the main heat exchanger.

A nitrogen generating device comprises: a main heat exchanger; a nitrogen distillation column; at least one nitrogen condenser; a compressor; an expansion turbine; a rotation control unit for controlling rotation with respect to a rotating shaft connecting the compressor and the expansion turbine; a pressure measuring unit for measuring a pressure value of product nitrogen gas; and an optimum rotational speed calculation command unit which inputs the pressure value measured by the pressure measuring unit into a pre-installed rotational speed calculation function to calculate the rotational speed of the rotating shaft, and issues a command to the rotation control unit.

The invention relates to a method for separating air by cryogenic distillation in a column system, comprising a first column operating at a first pressure and a second column operating at a second pressure, in which an argon-enriched flow is sent from an intermediate point of the first column to the tank of the second column and an argon-rich flow is drawn off at the top of the second column, wherein a nitrogen-enriched flow of the first column is compressed in a compressor, the compressed flow is sent to a head condenser of the second column after an expansion step and the vaporized flow is expanded in the condenser in a turbine where it at least partially liquefies.

An apparatus for the separation or liquefaction of a gas at cryogenic temperatures which comprises an isolated chamber comprises at least one front distillation column operating at cryogenic temperatures and also a pipe for transferring fluid coming from or going to the column, the pipe having a diameter D comprising a bend for changing the direction of flow of the fluid, with profiled deflector vanes placed inside the bend, with their concavity towards the centre of the bend forming a plurality of ducts.