The present disclosure provides a distillation tower for separating a feed stream. The distillation tower includes a controlled freeze zone section having a controlled freeze zone upper section and a controlled freeze zone lower section below the controlled freeze zone upper section. The controlled freeze zone section includes: (a) a spray assembly in the controlled freeze zone upper section; (b) a melt tray assembly in the controlled freeze zone lower section; (c) a feed stream distribution mechanism between the spray assembly and the melt tray assembly. The feed stream distribution mechanism is constructed and arranged to uniformly distribute the feed stream in the controlled freeze zone section.

In a process for the cryogenic separation of a methane-rich feed stream containing between 3 and 35% of oxygen and also nitrogen, the feed stream is cooled in order to produce a cooled stream, at least one portion of the cooled stream is sent to a distillation column, a bottom stream is withdrawn from the distillation column, the bottom stream being enriched in methane compared to the feed stream, a stream enriched in oxygen compared to the feed stream is withdrawn from the distillation column, and a nitrogen-rich stream is sent to the column.

A mixed single refrigerant process for separating a nitrogen gas stream from a natural gas stream containing nitrogen to produce a nitrogen gas stream from a liquefied natural gas stream wherein the separated nitrogen gas stream is used as a refrigerant for the natural gas stream and wherein the mixed refrigerant provides cooling for the process.

A process for removing light components from an ethylene stream may include providing a dried ethylene stream containing ethylene, ethane, CO, CO.sub.2, H.sub.2, CH.sub.4, and C.sub.3+ hydrocarbons. The process may include sending the dried ethylene stream to a stripper to produce an overhead stream containing ethylene, CO, H.sub.2 and CH.sub.4, and a bottom stream containing ethylene, ethane, CO.sub.2, and C.sub.3+ hydrocarbons. The gaseous phase on top of the stripper may be condensed in a heat exchanger cooled by a refrigerant stream to get a first gaseous phase and a first liquid phase. The first gaseous phase may be condensed in a heat exchanger cooled by liquid ethane or liquid ethylene to get a second gaseous phase containing ethylene CO, H.sub.2 and CH.sub.4 and a second liquid phase. The first and second liquid phases may be the reflux of the stripper.

A method for removing heavy hydrocarbons from a feed gas by: feeding, into an absorber, a top reflux stream and a second reflux stream below the top reflux stream, wherein the absorber produces an absorber bottom product stream and an absorber overhead product stream; depressurizing and feeding the absorber bottom product stream to a stripper to produce a stripper bottom product stream and a stripper overhead product stream; cooling and feeding a portion of the absorber overhead product stream back to the absorber as the top reflux stream; and pressurizing and feeding the stripper overhead stream back to the absorber as the second reflux stream. A system for carrying out the method is also provided.

Separating propane and heavier hydrocarbons from a feed stream by cooling the feed stream, introducing the chilled feed stream into a feed stream separation unit, pumping the separator bottom stream, introducing the pressurized separator bottom stream into a stripper column, reducing the pressure of the separator overhead stream, introducing the letdown separator overhead stream into an absorber column, collecting a stripper overhead stream from the stripper column, chilling the stripper overhead stream, reducing the pressure of the chilled stripper overhead stream, introducing the letdown stripper overhead stream into the absorber column, collecting an absorber bottom stream, pumping the absorber bottom stream, heating the absorber bottom stream, introducing the heated absorber bottom stream into the stripper column, and collecting the stripper bottom stream from the stripper column. The stripper column bottom stream includes the propane and heavier hydrocarbons and less than about 2.0% of ethane by volume.

This invention is about an air separation apparatus to produce oxygen and nitrogen through isobaric separation, which is based on the Rankine cycle system of similar thermal energy power circulation apparatus at cryogenic side, a liquid pump is used to input work and the cold is made up to the air separation apparatus with refrigerating media, so as to realize the isobaric separation of air to produce nitrogen and oxygen. The air separation apparatus of this invention can save energy by over 30% as compared with the traditional advanced apparatus with the identical refrigerating capacity, and it can also realize centralize gas supply via the air separation apparatus, therefore it constitutes a breakthrough to the traditional air separation technology and refrigeration theory, with substantial economic, social and environmental protection benefits.

A method for the cryogenic fractionation of air, in which a liquid volume present in a vaporization chamber in a distillation column system of an air fractionation plant is fed by means of a cryogenic liquid and in which a proportion of the liquid volume is continuously transferred into the gas phase by vaporization, wherein, in addition to oxygen, the cryogenic liquid contains components, including xenon, which are higher-boiling than oxygen. The content of xenon in the cryogenic liquid is determined and used as a measure of any enrichment of the components which are higher-boiling than oxygen in the cryogenic liquid. A corresponding air fractionation plant is also described.

Systems and methods are provided for recovering helium from a feed comprising helium, carbon dioxide, and at least one of nitrogen and methane. The feed is separated in a first separator to form helium-enriched stream and a CO.sub.2-enriched stream. The helium-enriched stream is separated in a pressure swing adsorption unit to form a helium-rich product stream and a helium-lean stream. At least a portion of the helium-lean stream is recycled to the first separator with the feed. In some embodiments, a membrane separation unit is used to enhance helium recovery.

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.