A liquefaction system that is configured to use a single methane expander to provide primary refrigeration duty. The liquefaction system can include a first or main heat exchanger and a fluid circuit coupled with the heat exchanger, the fluid circuit configured to circulate a process stream derived from an incoming feedstock of natural gas. The fluid circuit can comprise a compression circuit, methane expander coupled with the compression circuit and the main heat exchanger, a sub-cooling unit coupled with the methane expander, the sub-cooling unit configured to form a liquid natural gas (LNG) product from the process stream, and a first throttling device interposed between the main heat exchanger and the sub-cooling unit. The first throttling device can be configured to expand the process stream to a process pressure that corresponds with the suction pressure internal to the compression circuit.

A system for removing freezing components from a feed gas includes a heat exchanger, a scrub column and a return vapor expansion device. The heat exchanger includes a reflux cooling passage and a return vapor passage. Vapor from the scrub column is directed through the return vapor expansion device, where the temperature and pressure are lowered. The resulting cooled fluid then travels to the return vapor passage of the heat exchanger and is used to cool a vapor stream in the reflux cooling passage to create a reflux fluid stream that is directed to the scrub column.

A gas liquefaction apparatus includes at least a source-gas supply line that supplies source gas; a room-temperature heat exchanger, a preliminary-cooling heat exchanger, and a liquefaction/supercooling heat exchanger that are provided in series sequentially in the source-gas supply line and that cool the source gas; a separation drum that separates the source gas containing a condensate, which has been cooled by heat exchange up to a liquefaction temperature of the source gas or below, into a gas component and a liquefied component; and a refrigerant-gas supply line that uses a gas component separated by the separation drum as refrigerant gas to supply the refrigerant gas in a direction opposite to a supply direction of the source gas, in order of the liquefaction/supercooling heat exchanger, the preliminary-cooling heat exchanger, and the room-temperature heat exchanger.

A process for liquefying methane-rich gases comprising: (a) providing a stream of methane-rich feed gas containing higher hydrocarbons comprising C.sub.5+ hydrocarbons and/or aromatic compounds at a feed gas pressure of from 40 bar to 120 bar; (b) providing a stream of methane-rich recycle gas at a recycle gas pressure of from 40 bar to 120 bar; (c) mixing the feed gas with a first part of the recycle gas to form a mixture; (d) passing the resulting mixture to a first gas expander having an outlet, the first expander outlet having a first gas expander outlet pressure of between 3 bar and 50 bar and less than the feed gas and recycle gas pressures, to form a first gas expander outlet stream comprising a mixture of vapor and a condensed liquid containing the higher hydrocarbons; (e) separating the first gas expander outlet stream into a liquid stream and a vapor stream; (f) reheating and compressing the first vapor stream to a first vapor stream pressure of from 40 bar to 120 bar to form a first constituent of the recycle gas; (g) cooling a second part of the recycle gas to a temperature higher than an outlet temperature of the first gas expander; and, (h) liquefying said cooled second part of the recycle gas to form liquefied methane, wherein a content of C5+ hydrocarbons is about 0.1 mol % or less in the liquefied methane and a content of aromatic compounds is below 1 mol ppm in the liquefied methane.

In an embodiment, the cooled second part of the recycle gas is completely or substantially liquefied in step (h). In another embodiment, the second part of the recycle gas is liquefied to form liquefied methane and a second vapor stream in step (h), and the second vapor stream is reheated and compress in a step (i) to a second vapor stream pressure of from 40 bar to 120 bar to form a second constituent of the recycle gas.

The invention relates to a method and system of preparing a lean methane-containing gas stream (22), comprising: feeding a hydrocarbon feed stream (10) into a separator (100); withdrawing from the separator (100) a liquid bottom stream (12); passing the liquid bottom stream (12) to a stabilizer column (200); withdrawing from the stabilizer column (200) a stabilized condensate stream (13) enriched in pentane, withdrawing from the stabilizer column (200) a stabilizer overhead stream (14) enriched in ethane, propane and butane; splitting the stabilizer overhead stream (14) according to a split ratio into a main stream portion (15) and a slip stream portion (16), passing the slip stream portion (16) to a fractionation unit (300) to obtain an ethane enriched stream (17) and a bottom stream enriched in propane and butane (18).

A process for liquefying methane-rich gases comprising providing a stream of feed methane-rich gas at a pressure of from 40 bar to 120 bar and containing higher hydrocarbons; providing a stream of methane-rich recycle gas at a pressure of from 40 bar to 120 bar; mixing the feed gas with a first part of the recycle gas; passing the resulting mixture to a gas expander, the expander outlet having a pressure of between 3 bar and 50 bar, so as to form a mixture of vapor and a condensed liquid containing higher hydrocarbons; separating the expander outlet stream into a liquid stream and a vapor stream; reheating and compressing said vapor stream to a pressure of from 40 bar to 120 bar to form a first constituent of the above-said recycle gas; cooling a second part of the said recycle gas to a temperature higher than the outlet temperature of the said expander; passing said cooled second part of the recycle gas into a liquefaction unit to form liquefied methane and a second vapor stream; reheating and compressing said second vapor stream to a pressure of from 40 bar to 120 bar to form a second constituent of the above-said recycle gas.

The method for producing liquid hydrogen can include the steps of: introducing pressurized natural gas from a high pressure natural gas pipeline to a gas processing unit under conditions effective for producing a purified hydrogen stream; and introducing the purified hydrogen stream to a hydrogen liquefaction unit under conditions effective to produce a liquid hydrogen stream, wherein the hydrogen liquefaction unit provides a warm temperature cooling and a cold temperature cooling to the purified hydrogen stream, wherein the warm temperature cooling is provided by utilizing letdown energy of a pressurized stream selected from the group consisting of a nitrogen stream sourced from a nitrogen pipeline, a natural gas stream sourced from the high pressure natural gas pipeline, an air gas sourced from an air separation unit, and combinations thereof, wherein the cold temperature is provided by utilizing letdown energy of the purified hydrogen stream.

A proposed method provides a highly efficient fueled power output augmentation of the liquid air energy storage (LAES) through its integration with the semi-closed CO.sub.2 bottoming cycle. It combines the production of liquid air in air liquefier during LAES charge using excessive power from the grid and an effective recovery of stored air for production of on-demand power in the fueled supercharged reciprocating internal combustion engine (ICE) and associated expanders of the power block during LAES discharge. A cold thermal energy of liquid air being re-gasified is recovered for cryogenic capturing most of CO.sub.2 emissions from the facility exhaust with following use of the captured CO.sub.2 in the semi-closed bottoming cycle, resulting in enhancement of total LAES facility discharge power output and suppressing the thermal NOx formation in the ICE.

A method for large-scale offshore LNG production from natural gas gathered from an onshore gas pipe network is described. The natural gas is pre-treated on an onshore facility for removal of mercury, acid gas, water and C5+ hydrocarbons, and then compressed and piped to an offshore platform for further compression and cooling before being transferred to a floating liquefaction, storage and offloading vessel for liquefaction of the natural gas.

A system for removing freezing components from a feed gas includes a heavy hydrocarbon removal heat exchanger and a scrub device. The scrub device includes a scrub column that receives a cooled feed gas stream from the heat exchanger and a reflux separation device. Vapor from the scrub column is directed to the heat exchanger and cooled to create a reflux stream that includes a liquid component. This reflux stream is directed to the reflux separation device and a resulting liquid component stream is used to reflux the column. Vapor from the reflux separation device is expanded and directed to the heat exchanger, where it provides refrigeration, and a processed feed gas line.