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.

A process for producing liquefied natural gas and liquid carbon dioxide comprising: Step a): separating a natural gas feed gas into a CO.sub.2-enriched gas stream and a CO.sub.2-depleted natural gas stream; Step b): liquefying the CO.sub.2-depleted natural gas stream in a liquefaction unit comprising at least a main heat exchanger and a system for producing frigories, said liquefaction unit comprising at least one refrigeration cycle fed by a refrigerant stream; Step c): simultaneous liquefying of the CO.sub.2-enriched gas stream resulting from step a) in a CO.sub.2 liquefaction unit; wherein the refrigeration necessary for the liquefaction of the CO.sub.2-enriched gas stream and for the liquefaction of the natural gas is supplied by said frigorie-producing system of the liquefaction unit and in that the refrigeration necessary for the liquefaction of the CO.sub.2-enriched gas stream originates from a portion of said refrigerant stream supplying the refrigeration cycle of said liquefaction unit.

A process for producing liquefied natural gas and liquid carbon dioxide from a natural gas feed gas comprising at least the following steps: Separation of a natural gas feed gas into a CO.sub.2-enriched gas stream and a natural gas stream; Cooling of said natural gas in a heat exchanger; Purification of the in step 1 from compounds containing at least six carbon atoms; At least partial condensation of said gas stream resulting from step 3 to form a two-phase stream; Separation of said two-phase stream resulting from step 4 to form a gas stream and a liquid stream; Condensation of the gas stream resulting from step 5 to form a liquefied gas containing less than 5 ppm by volume of compounds containing at least six carbon atoms; Liquefaction of the CO.sub.2-enriched gas stream resulting from step 1 with a portion of the liquid stream resulting from step 5.

Method and system for removing high freeze point components from natural gas. Feed gas is cooled in a heat exchanger and separated into a first vapor portion and a first liquid portion. The first liquid portion is reheated using the heat exchanger and separated into a high freeze point components stream and a non-freezing components stream. A portion of the non-freezing components stream may be at least partially liquefied and received by an absorber tower. The first vapor portion may be cooled and received by the absorber tower. An overhead vapor product which is substantially free of high freeze point freeze components and a bottoms product liquid stream including freeze components and non-freeze components are produced using the absorber tower.

A gas recovery system for a compressor, said gas recovery system being equipped with: a distillation column that brings a supply gas in a liquid state into contact with a mixed gas, thereby cooling and liquefying a process gas in the mixed gas, and heating and gasifying the liquid supply gas; a process gas recovery line that is connected to the lower part of the distillation column and recovers the liquid process gas discharged from the distillation column; and a supply gas recovery line that is connected to the upper part of the distillation column and recovers the gaseous supply gas discharged from the distillation column.

A LNG liquefaction plant includes a propane recovery unit including an inlet for a feed gas, a first outlet for a LPG, and a second outlet for an ethane-rich feed gas, an ethane recovery unit including an inlet coupled to the second outlet for the ethane-rich feed gas, a first outlet for an ethane liquid, and a second outlet for a methane-rich feed gas, and a LNG liquefaction unit including an inlet coupled to the second outlet for the methane-rich feed gas, a refrigerant to cool the methane-rich feed gas, and an outlet for a LNG. The LNG plant may also include a stripper, an absorber, and a separator configured to separate the feed gas into a stripper liquid and an absorber vapor. The stripper liquid can be converted to an overhead stream used as a reflux stream to the absorber.

Systems, devices, and methods for recovering mixed refrigerant and/or nitrogen within liquefaction systems are provided. The systems, devices, and methods facilitate recovering mixed refrigerant (MR) and/or nitrogen vapor that can leak from a compressor, separating the MR from the nitrogen, and reusing the MR and/or the nitrogen within the liquefaction system. Recovering and reusing MR and/or nitrogen can minimize loss of MR and nitrogen which can lower the total operating cost of a liquefaction system. Additionally, recovering the MR, rather than burning it, can reduce environmental emissions by reducing the amount of MR that is burned.

The invention relates to an integrated process and apparatus for liquefaction of natural gas and recovery of natural gas liquids. In particular, the improved process and apparatus reduces the energy consumption of a Liquefied Natural Gas (LNG) unit by using a portion of the already cooled overhead vapor from a fractionation column from an NGL (natural gas liquefaction) unit to, depending upon composition, provide, for example, reflux for fractionation in the NGL unit and/or a cold feed for the LNG unit, or by cooling, within the NGL unit, a residue gas originating from a fractionation column of the NGL unit and using the resultant cooled residue gas to, depending upon composition, provide, for example, reflux/feed for fractionation in the NGL and/or a cold feed for the LNG unit, thereby reducing the energy consumption of the LNG unit and rendering the process more energy-efficient.

Integrated systems are provided for the production of higher hydrocarbon compositions, for example liquid hydrocarbon compositions, from methane using an oxidative coupling of methane system to convert methane to ethylene, followed by conversion of ethylene to selectable higher hydrocarbon products. Integrated systems and processes are provided that process methane through to these higher hydrocarbon products.

Helium can be recovered from nitrogen-rich natural gas at high pressure with low helium loss by cryogenic distillation of the natural gas after pre-treatment of the gas to remove incompatible impurities and then recovery of natural gas liquid (NGL) from the pre-treated gas by distillation. Overall power consumption may be reduced, particularly if the feed to the helium recovery column system is at least substantially condensed by indirect heat exchange against a first portion of nitrogen-enriched bottoms liquid at first pressure, and a second portion of nitrogen-enriched bottoms liquid at a second pressure that is different from the first pressure.