A process for separating a component mixture comprising essentially hydrocarbons having two or two or more carbon atoms, methane and hydrogen using a distillation apparatus (10) is proposed. Fluid (a, c, e, g, i) from the component mixture is cooled stepwise to a first pressure level, with separation of first condensates (b, d, f, h, j) out of the fluid (a, c, e, g, i) in each case. Fluid (k) from the component mixture that remains in gaseous form thereafter is expanded to a second pressure level in an expander, giving a second condensate (l). Fluid from the first condensates (b, d, f, h, j) is expanded from the first pressure level to the second pressure level and fed together with the fluid from the second condensates into the distillation apparatus (10) which is being operated at the second pressure level. The present invention likewise provides a corresponding separation apparatus.

A method and apparatus for producing liquefied natural gas. A portion of a natural gas stream is cooled in a first heat exchanger and re-combined with the natural gas stream, and heavy hydrocarbons are removed therefrom to generate a separated natural gas stream and a separator bottom stream. Liquids are separated from the separator bottom stream to form an overhead stream, which is cooled and separated to form a recycle gas stream. The recycle gas stream is compressed. A first portion of the compressed recycle gas stream is directed through the first heat exchanger and directed to the separator as a column reflux stream. The separated to natural gas stream is used as a coolant in the first heat exchanger to thereby generate a pretreated natural gas stream, which is compressed and liquefied.

A method and apparatus for producing liquefied natural gas. A portion of a natural gas stream is cooled in a heat exchanger and combined with the natural gas stream. Heavy hydrocarbons are removed from the combined natural gas stream, and the resulting separated natural gas stream is partially condensed in the first heat exchanger, with a liquid stream separated therefrom. The natural gas stream is warmed in the first heat exchanger and then is compressed and cooled. The resultant cooled compressed natural gas stream is expanded, thereby forming a chilled natural gas stream that is separated into a refrigerant stream and a non-refrigerant stream. The refrigerant stream recycled to the heat exchanger to be warmed through heat exchange with one or more process streams associated with pretreating the natural gas stream, thereby generating a warmed refrigerant stream. The warmed refrigerant stream and the non-refrigerant stream are liquefied.

A process is described herein for removing high freeze point hydrocarbons, including benzene compounds, from a mixed feed gas stream. The process involves cooling process streams in one or more heat exchangers and separating condensed compounds in multiple separators to form a methane-rich product gas stream. Select solvent streams from a fractionation train and/or separate solvent streams are employed to lower the freeze point of one or more streams that contain high freeze point hydrocarbons. A corresponding system also is disclosed.

Process for extracting nitrogen from a feed stream of natural gas or of biomethane comprising at least nitrogen, methane, CO.sub.2 and/or H.sub.2S, wherein a liquid stream enriched in methane resulting from a cryogenic separation is recovered by pumping the bottom product of one or more of the columns and/or pumping a liquid stream to a pressure P2 greater than 25 bar absolute and preferably greater than the critical pressure of said product.

A process and plant for natural gas liquids (NGL) recovery includes a main heat exchanger, a cold gas/liquid separator, a separation or distillation column, and an overhead gas heat exchanger. A pressurized residue gas generated from an overhead gas stream removed the top of the separation or distillation column is expanded and used as a cooling medium in the overhead gas heat exchanger and the main heat exchanger. The expanded residue gas, used as a cooling medium, is then compressed up to a pressure to be combined with the overhead stream from the separation or distillation column.

The present invention relates to a cold box cycle which allows for independent control of the heat supplied for reboilers associated with the separation columns. More specifically, the invention relates to the tight control of the hydrogen removal separation, thus avoiding the possibility of excess reboiling in this separation. Optimal reboiling also results in a lower temperature of the hydrogen depleted liquid from this separation. As this stream is used to provide a portion of the cooling at the cold end of the primary heat exchanger, lower temperatures facilitate cooling of the incoming syngas feed, reducing carbon monoxide (CO) losses into the crude hydrogen stream from the high pressure separator. Lower CO in the crude hydrogen allows for smaller hydrogen purification equipment.

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.

The invention relates to a method (100, 200) of obtaining one or more olefins, in which, using an oxidative coupling of methane (10), a gas mixture comprising hydrogen, methane, carbon monoxide and higher-boiling hydrocarbons than methane is formed and is subjected to a low-temperature separation (1-5), characterized in that the low-temperature separation (1-5) is conducted using a rectification column (2) having a first separation region (21), a second separation region (22) arranged above the first separation region (21), and a condenser-evaporator (23), wherein the gas mixture is cooled, fed at least partly as first separation feed into the first separation region (21) and subjected to a first rectification in the first separation region (21) to form a first tops gas and a first bottoms liquid, wherein, using a first proportion of the first tops gas in the condenser-evaporator (23), a condensate which is recycled to the first separation region and, using a second proportion of the tops gas, a second separation feed which is fed into the second separation region (22) are formed, and wherein the second separation feed is subjected to a second rectification in the second separation region to form a second tops gas and a second bottoms liquid.

The present invention is directed to a method and system of separating carbon monoxide from syngas mixtures with high methane content by cryogenic means where a partial condensation cycle is generally employed, and more specifically towards combining the methane-rich liquid exiting the distillation column with a lower-boiling mixture so that the boiling point of the combined stream is lower than the boiling point of the methane-rich liquid.