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 provides a method of liquefying a contaminated hydrocarbon-containing gas stream: (a) providing a CO2 contaminated hydrocarbon-containing gas stream (20); (b) cooling the contaminated hydrocarbon-containing gas stream to obtain a partially liquefied stream (70); (c) separating the partially liquefied stream obtaining a liquid stream (90); (d) cooling the liquid stream (90) in a direct contact heat exchanger (200) obtaining a multiphase stream (201) containing at least a liquid phase and a solid CO2 phase; (e) separating the multiphase stream in a solid-liquid separator (202) obtaining a CO2 depleted liquid stream (141); (f) passing the CO2 depleted liquid stream (141) to a further cooling, pressure reduction and separation stage to generate a further CO2 enriched slurry stream (206); (g) passing at least part of the further CO2 enriched slurry stream (206) to the direct contact heat exchanger (200) to provide cooling duty to and mix with the liquid stream (90).

A process and an apparatus are disclosed for a compact processing assembly to improve the recovery of C.sub.2 (or C.sub.3) and heavier hydrocarbon components from a hydrocarbon gas stream. The preferred method of separating a hydrocarbon gas stream generally includes producing at least a substantially condensed first stream and a cooled second stream, expanding both streams to lower pressure, and supplying the streams to a fractionation tower. In the process and apparatus disclosed, the tower overhead vapor is directed to an absorbing means and a heat and mass transfer means inside a processing assembly. A portion of the outlet vapor from the processing assembly is compressed to higher pressure, cooled and substantially condensed in a heat exchange means inside the processing assembly, then expanded to lower pressure and supplied to the heat and mass transfer means to provide cooling. Condensed liquid from the absorbing means is fed to the tower.

A process and an apparatus are disclosed for a compact processing assembly to improve the recovery of C.sub.2 (or C.sub.3) and heavier hydrocarbon components from a hydrocarbon gas stream. The preferred method of separating a hydrocarbon gas stream generally includes producing at least a substantially condensed first stream and a cooled second stream, expanding both streams to lower pressure, and supplying the streams to a fractionation tower. In the process and apparatus disclosed, the tower overhead vapor is directed to an absorbing means and a heat and mass transfer means inside a processing assembly. The outlet vapor from the processing assembly is compressed to higher pressure and cooled, then a portion is substantially condensed in a heat exchange means inside the processing assembly, expanded to lower pressure, and supplied to the heat and mass transfer means to provide cooling. Condensed liquid from the absorbing means is fed to the tower.

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 present invention provides a method to separate CO2 from a contaminated hydrocarbon-containing stream. The method comprises obtaining a multiphase contaminated hydrocarbon-containing stream (100) containing at least a vapour phase, a liquid phase and a solid phase, creating a slurry stream (120) from the multiphase stream. The slurry stream is fed to a crystallization chamber comprising CO2 seed particles. A liquid hydrocarbon stream (170) is obtained from the crystallization chamber (91) and a concentrated slurry (140) is obtained. The concentrated slurry (140) is removed from the crystallization chamber (91) by means of an extruder (142), thereby obtaining solid CO2. A feedback stream (141) is obtained from the solid CO2 comprising CO2 seed particles having an average size greater than 100 micron. The feedback stream (141) is passed into the crystallization chamber (91).

A process and an apparatus are disclosed for a compact processing assembly to improve the recovery of C.sub.2 (or C.sub.3) and heavier hydrocarbon components from a hydrocarbon gas stream. The preferred method of separating a hydrocarbon gas stream generally includes producing at least a substantially condensed first stream and a cooled second stream, expanding both streams to lower pressure, and supplying the streams to a fractionation tower. In the process and apparatus disclosed, the tower overhead vapor is directed to an absorbing means and a heat and mass transfer means inside a processing assembly. A portion of the outlet vapor from the processing assembly is compressed to higher pressure, cooled and substantially condensed in a heat exchange means inside the processing assembly, then expanded to lower pressure and supplied, to the heat and mass transfer means to provide cooling. Condensed liquid from the absorbing means is fed to the tower.

A system and method for removing nitrogen and producing a high pressure methane product stream and an NGL product stream from natural gas feed streams where at least 90%, and preferably at least 95%, of the ethane in the feed stream is recovered in the NGL product stream. The system and method of the invention are particularly suitable for use with feed streams in excess of 5 MMSCFD and up to 300 MMSCFD and containing around 5% to 80% nitrogen. The system and method preferably combine use of strategic heat exchange between various process streams with a high pressure rectifier tower and the ability to divert all or a portion of a nitrogen rejection unit feed stream to optionally bypass a nitrogen fractionation column to reduce capital costs and operating expenses.

The process comprises the following steps: mixing a gaseous stream of flash gas and a gaseous stream of boil-off gas to form a mixed gaseous flow; compressing the mixed gaseous flow in at least one compression apparatus to form a flow of compressed combustible gas; withdrawing a bypass flow in the flow of compressed combustible gas; compressing the bypass flow in at least one downstream compressor; cooling and expanding the compressed bypass flow; reheating at least a first stream derived from the expanded bypass flow in at least one downstream heat exchanger, reintroducing the first reheated stream in the mixed gaseous flow upstream from the compression apparatus.

A system and method for liquefaction of natural gas using two distinct refrigeration circuits having compositionally different working fluids and operating at different temperature levels is provided. The turbomachinery associated with the liquefaction system are driven by a single three-pinion or four-pinion integral gear machine with customized pairing arrangements. The system and method of natural gas liquefaction further includes the conditioning of a lower pressure natural gas containing feed stream to produce a purified, compressed natural gas stream at a pressure equal to or above the critical pressure of natural gas and substantially free of heavy hydrocarbons to be liquefied.