A system and method for removing nitrogen and producing a high pressure methane product stream from natural gas feed streams having wide variations in nitrogen and methane content are disclosed. Optional add-on systems may be incorporated into the nitrogen and methane separation to produce an NGL sales stream to reduce excess hydrocarbons in the nitrogen vent stream, or to recover helium. The system and method of the invention are particularly suitable for use with feed streams in excess of 50 MMSCFD and up to 300 MMSCFD and containing up to 100 ppm carbon dioxide. Typical power requirements for compressing the methane product stream to produce a suitably high pressure stream for sale are reduced according to the systems and methods of the invention.

A system and method for separating air by cryogenic distillation using a four column arrangement including a higher pressure column, a lower pressure column, an intermediate pressure column, and an argon column is provided. The disclosed system and method is particularly suited for production of normal purity oxygen and employs a once-through kettle column reboiler, a once-through kettle column condenser, and a once-through argon condenser. The once through argon condenser is disposed within the lower pressure column where an argon-rich vapor stream is condensed against the descending liquid in the lower pressure column.

Embodiments of apparatuses and methods for reforming of hydrocarbons including recovery of products are provided. In one example, a method comprises separating a reforming-zone effluent to form a net gas phase stream and a liquid phase hydrocarbon stream. The net gas phase stream is compressed, partially condensed and cooled to form a partially condensed, compressed net gas phase stream. The partially condensed, compressed net gas phase stream is separated to form an intermediate gas phase stream. The intermediate gas phase stream is cooled to form a cooled intermediate gas phase stream. The liquid phase hydrocarbon stream is cooled to form a cooled liquid phase hydrocarbon stream. The cooled intermediate gas phase stream is contacted with the cooled liquid phase hydrocarbon stream to form an H.sub.2-rich stream and a cooled second intermediate liquid phase hydrocarbon stream that is enriched with C.sub.3/C.sub.4 hydrocarbons.

A system and method for removing nitrogen and producing a high pressure methane product stream from natural gas feed streams having wide variations in nitrogen and methane content are disclosed. Optional add-on systems may be incorporated into the nitrogen and methane separation to produce an NGL sales stream to reduce excess hydrocarbons in the nitrogen vent stream, or to recover helium. The system and method of the invention are particularly suitable for use with feed streams in excess of 50 MMSCFD and up to 300 MMSCFD and containing up to 100 ppm carbon dioxide. Typical power requirements for compressing the methane product stream to produce a suitably high pressure stream for sale are reduced according to the systems and methods of the invention.

An improved process for liquid nitrogen production by cryogenic air separation using a distillation column system to enhance the product recovery.

Embodiments of apparatuses and methods for reforming of hydrocarbons including recovery of products are provided. In one example, a method comprises separating a reforming-zone effluent to form a net gas phase stream and a liquid phase hydrocarbon stream. The net gas phase stream is compressed, partially condensed and cooled to form a partially condensed, compressed net gas phase stream. The partially condensed, compressed net gas phase stream is separated to form an intermediate gas phase stream. The intermediate gas phase stream is cooled to form a cooled intermediate gas phase stream. The liquid phase hydrocarbon stream is cooled to form a cooled liquid phase hydrocarbon stream. The cooled intermediate gas phase stream is contacted with the cooled liquid phase hydrocarbon stream to form an H.sub.2-rich stream and a cooled second intermediate liquid phase hydrocarbon stream that is enriched with C.sub.3/C.sub.4 hydrocarbons.

Embodiments of apparatuses and methods for reforming of hydrocarbons including recovery of products are provided. In one example, a method comprises separating a reforming-zone effluent to form a net gas phase stream and a liquid phase hydrocarbon stream. The net gas phase stream is compressed, partially condensed and cooled to form a partially condensed, compressed net gas phase stream. The partially condensed, compressed net gas phase stream is separated to form an intermediate gas phase stream. The intermediate gas phase stream is cooled to form a cooled intermediate gas phase stream. The liquid phase hydrocarbon stream is cooled to form a cooled liquid phase hydrocarbon stream. The cooled intermediate gas phase stream is contacted with the cooled liquid phase hydrocarbon stream to form an H.sub.2-rich stream and a cooled second intermediate liquid phase hydrocarbon stream that is enriched with C.sub.3/C.sub.4 hydrocarbons.

The method according to the invention comprises the separation of a feed stream (16) into a first fraction (60) and a second fraction (62) and the injection of at least part of the second fraction (62) into a second dynamic expansion turbine (46) to form a second expanded fraction (80). It comprises the cooling of the second expanded fraction (80) through heat exchange with at least part of the first headstream (84) coming from a first column (28) and the formation of a second feed stream (82) of the first column (28) from the second cooled expanded fraction.

A method of gas production from a field containing natural gas processing particularly for transport of stranded gas to conserve resources and reduce emissions includes extracting gas a gas supply from a plurality of individual gas wells in the field and initially at the individual gas wells providing a recovery unit having a production capacity matching that of the well for carrying out liquid recovery from the gas supply and compression of the natural gas. When a production rate of the well declines to a low level, typically to about 20% of the original, the recovery unit is removed for redeployment either at a central plant or at other wells which are still at the high production and is substituted by a dehydration system and gas compressor arranged to fill portable pressure vessels typically on trucks for transporting the compressed natural gas to a main pipe line.

A process for producing high-purity methane is disclosed wherein a mixture containing predominantly methane, and at least one higher hydrocarbon, such as ethane or propane, and nitrogen is liquefied and fed to a first fractionation column that removes nitrogen and other light gases from the mixture through the top of the first fractionation column as a vapor. The remainder of the mixture is fed to a second fractionation column that removes the higher hydrocarbons and other heavier components through the bottom of the second fractionation column as a liquid producing high-purity methane out the top of the second fractionation column as a vapor. The high-purity methane vapor is warmed, compressed, and liquefied by heat exchange. The liquid leaving the second fractionation column can be further purified in a stripping column to remove non-hydrocarbon components such as carbon dioxide.