A method of stripping carbon dioxide from a stream of natural gas to be used in the production of liquid natural gas (LNG) comprises the steps of: passing a stream of natural gas through a stripping column; injecting a stripping agent into the stripping column, the stripping agent stripping carbon dioxide from the stream of natural gas and exiting the stripping column as a liquid phase; passing the stripping agent exiting the stripping column through a regenerator column to generate a carbon dioxide gas stream and a recovered stripping agent stream; and cooling the recovered stripping agent stream using a cryogenic vapour generated in the production of LNG and injecting the cooled, recovered stripping agent stream into the stripping column as the stripping agent.

A method for separating nitrogen from an inlet gas having less than 25 mole % nitrogen includes supplying the inlet gas having less than 25 mole % nitrogen to a nitrogen separation system configured with cryogenic refrigeration.

A system and method for removing nitrogen from natural gas using two fractionating columns, that may be stacked, and a plurality of separators and heat exchangers, with horsepower requirements that are 50-80% of requirements for prior art systems. The fractionating columns operate at different pressures. A feed stream is separated with a vapor portion feeding the first column to produce a first column bottoms stream that is split into multiple portions at different pressures and first column overhead stream that is split or separated into two portions at least one of which is subcooled prior to feeding the top of the second column. Optional heat exchange between first column and second column streams provides first column reflux and reboil heat for a second column ascending vapor stream. Three sales gas streams are produced, each at a different pressure.

A system and method for producing an NGL product stream in either an ethane retention or rejection mode. Rejection modes include (a) two heat exchange stages between a feed stream and first separator bottoms stream and cooling a side stream withdrawn from a fractionation tower through heat exchange with both the fractionation tower and second separator overhead streams; or (b) warming the first separator bottoms stream and fractionation overhead stream through heat exchange with the side stream prior to heat exchange with the feed stream, to achieve 4-15% ethane recovery and 97%+ propane recovery. In ethane retention mode, a portion of the feed stream and portions of a first separator overhead and bottoms streams are separately cooled through heat exchange with other process streams, including the entireties of a recycled residue gas and fractionation column overhead streams, resulting in around 99% ethane and around 100% propane recovery.

The invention relates to various nonlimiting embodiments that include methods, apparatuses or systems for processing natural gas comprising a heavies removal column processing natural gas and light oil reflux. The overhead stream goes to heavies treated natural gas storage. The heavies removal column reboiler bottoms stream product is input to a debutanizer column. The debutanizer column overhead lights are input to a flash drum where the bottoms is pumped through a heat exchanger as a light oil reflux input to the heavies removal column, while the debutanizer reboiler bottoms product is stored as stabilized condensate. Alternatively, debutanizer column overhead lights are sent to heavies treated gas storage and the bottoms stream product goes to a depentanizer column, the overhead lights are pumped through a heat exchanger as a light oil reflux input to the heavies removal column, while the depentanizer reboiler bottoms product is stabilized condensate.

A system and method for argon and nitrogen extraction and liquefaction from a low-pressure tail gas of an ammonia production plant is provided. The preferred tail gas of the ammonia production plant comprises methane, nitrogen, argon, and hydrogen. The disclosed system and method provides for the methane rejection via rectification and hydrogen rejection by way of a side stripper column or phase separator. The resulting nitrogen and argon containing stream is separated and liquefied in a double column distillation system.

Methods and systems for operating and NGL recovery process are provided. In an exemplary method, an absorber column upstream of a fractionator column is operated at a higher pressure than a pressure in the fractionator column. An NGL (C.sub.3 plus) stream is taken from the bottom of a fractionator column and then ethylene/ethane stream is taken from the top of the fractionator column. A differential pressure between the absorber column and the fraction are column is controlled based, at least in part, on a flow rate of the fractionator feed stream from the absorber column to the fractionator column.

Implementations described and claimed herein provide systems and methods for processing liquefied natural gas (LNG). In one implementation, a dry feed gas is received. The dry feed gas is chilled with clean vapor from a heavies removal column to form a chilled feed gas. The chilled feed gas is partially condensed into a vapor phase and a liquid phase. The liquid phase retains freezing components. The freezing components are extracted using a reflux stream in the heavies removal column. The freezing components are removed as a condensate. The vapor phase is compressed into a clean feed gas. The clean feed gas is free of the freezing components for downstream liquefaction.

Implementations described and claimed herein provide systems and methods for removing nitrogen during liquefaction of natural gas. In one implementation, a nitrogen rejection unit is used in an LNG facility to remove nitrogen from natural gas during an LNG liquefaction process. The nitrogen rejection unit contains at least two columns and at least one 3-stream condenser, 2-stream condenser or a two 2-stream condenser.

Systems and processes for upgrading natural gas liquids (NGL). A natural gas, preferably a shale gas, comprising methane and one or more natural gas liquids can be converted to one or more liquid hydrocarbons. Methane can be separated from the one or more liquid hydrocarbons using a liquid absorbent to provide a first separated stream comprising the methane from the converted stream and a second separated stream comprising the one or more liquid hydrocarbons from the converted stream. At least a portion of the one or more liquid hydrocarbons can be recycled as the liquid absorbent.