An apparatus for the distillation of air by cryogenic distillation is provided. The apparatus can include an enclosure; a first distillation column configured to operate at a first pressure; a second distillation column configured to operate at a second pressure that is lower than the first pressure, the second distillation column being placed above the first distillation column and forming therewith a double column; a subcooling heat exchanger configured to cool at least one liquid from the first distillation column upstream of the second distillation column and configured to warm a gaseous nitrogen stream from the second distillation column; and an argon column configured to separate an argon enriched stream from the second distillation column and configured to produce an argon rich stream. In certain embodiments, the first distillation column, the second distillation column, the argon column and the subcooling heat exchanger are disposed within the enclosure, and/or the subcooling heat exchanger is disposed directly underneath the first distillation column or the argon column.

A method of obtaining a liquefied hydrocarbon-rich fraction (product fraction) having a nitrogen content of 1 mol %, wherein the hydrocarbon-rich fraction is liquefied and subcooled with a refrigeration circuit and then subjected to a rectificative removal of nitrogen is disclosed.

A supply quantity adjustment device 500 comprises: a total demand quantity calculation unit 502 that calculates a total demand quantity used at a supply destination, based on plant information; an excess/deficit information setting unit 503 that compares the total demand quantity and a flow rate set value and sets a first calculated pressure value; a backup coefficient setting unit that sets a backup coefficient set value based on a reference gasholder pressure, the first calculated pressure value, a reference backup pressure set value, and a measured gasholder pressure value; and a production coefficient setting unit that compares a production pressure set value obtained by adding the reference gasholder pressure and a first pressure output value with the measured gasholder pressure value, and sets a production coefficient so as to modify a variation in the quantity of product gas produced by the air separation apparatus.

A method for the production of air gases by the cryogenic separation of air can include the steps of sending a purified and compressed air stream to a cold box under conditions effective for cryogenically separating the air stream into oxygen and nitrogen using a system of columns, wherein the purified and compressed air stream is at a feed pressure when entering the system of columns; withdrawing the oxygen at a product pressure; delivering the oxygen at a delivery pressure to an oxygen pipeline, wherein the oxygen pipeline has a pipeline pressure; and monitoring the pipeline pressure. The method can also include a controller configured to determine whether to operate in a power savings mode or a variable liquid production mode. By operating the method in a dynamic fashion, a power savings and/or additional high value cryogenic liquids can be realized in instances in which the pipeline pressure deviates from its highest value.

A method is provided for determining a state of a distillation column having multiple column stages for separating a feed fluid stream into individual fluid components. The state is determined by means of a model in a manner dependent on pressure differences prevailing between adjacent column stages. In the model, both gaseous and liquid flows between adjacent column stages are brought about by the pressure differences prevailing between adjacent column stages. A substance quantity flow characterizing gaseous flow between two column stages is given by {dot over (N)}.sub.V.Math.R.sub.V=C.sub.V.Math.p.sub.V. A substance quantity flow characterizing liquid flow between two column stages is given by {dot over (N)}.sub.L.Math.R.sub.L=C.sub.L.Math.p.sub.L. p.sub.V,L is a total pressure difference between two adjacent column stages. R.sub.V,L is a coefficient of resistance between two adjacent column stages and C.sub.V,L is a conductance value of flow between two adjacent column stages.

Disclosed are a method, a device, and a storage medium for measuring the nitrogen content. The method includes determining related variables associated with the nitrogen content; establishing an initial model, wherein the initial model takes the related variables as independent variables and the nitrogen content as dependent variables according to a historical operation data, and calculating parameters in the initial model; according to parameters in the initial model, obtaining parameters in a soft-sensing model by fitting; according to detected values of the related variables and the soft-sensing model, predicting the nitrogen content in real-time; and according to the predicted nitrogen content and an actual nitrogen content obtained by periodic sampling, obtaining a fusion detection result.

A method and main heat exchange system for use in a cryogenic air separation plant in which down-flow and thermosiphon heat exchangers are employed to partially vaporize an oxygen-rich liquid produced in a lower pressure column and to condense the nitrogen-rich vapor in a higher pressure column. A greater proportion of the oxygen-rich liquid can be partially vaporized in the down-flow heat exchangers than in the thermosiphon heat exchangers and the nitrogen-rich vapor condensed in the thermosiphon heat exchangers can have a higher oxygen content than the nitrogen-rich vapor condensed in the down-flow heat exchangers. This allows the higher pressure column to operate at a lower pressure than would otherwise be possible. A central conduit can extend from the higher pressure column into the lower pressure column to introduce the nitrogen-rich vapor into at least the down-flow heat exchangers for purposes of reducing pressure drop and column height.

A method of obtaining a liquefied hydrocarbon-rich fraction (product fraction) having a nitrogen content of 1 mol %, wherein the hydrocarbon-rich fraction is liquefied and subcooled with a refrigeration circuit and then subjected to a rectificative removal of nitrogen is disclosed.

Disclosed are a method, a device, and a storage medium for measuring the nitrogen content. The method includes determining related variables associated with the nitrogen content; establishing an initial model, wherein the initial model takes the related variables as independent variables and the nitrogen content as dependent variables according to a historical operation data, and calculating parameters in the initial model; according to parameters in the initial model, obtaining parameters in a soft-sensing model by fitting; according to detected values of the related variables and the soft-sensing model, predicting the nitrogen content in real-time; and according to the predicted nitrogen content and an actual nitrogen content obtained by periodic sampling, obtaining a fusion detection result.