The present disclosure provides a system and method of efficiently designing a compact and modularized midscale liquefied natural gas production train. The train includes Natural Gas Pretreatment and Natural Gas Liquefaction sections designed in a unique way that reduces footprint, capital and operating cost, and overall project schedule. The train is configured into a framed compact multi-level structure with air coolers on the top level and process equipment underneath, which results in significant reduction in footprint compared to conventional stick-built design and significant reduction in footprint compared to conventional modularized design.

An offshore LNG processing plant includes a first module including a personnel accommodation facility on a first vessel, a second module including a gas treatment facility on a second vessel, and a third module including a gas liquefaction facility on a third vessel. Each of the first, second, and third modules are assembled on the corresponding vessels, and then transported to an offshore location in a body of water, such as a river, a lake, or a sea. At the offshore location, each vessel deploys legs to the bed of the body of water to raise a hull of each vessel out of the water. The first module is then coupled to the second module, and the second module is coupled to the third module. A fourth module on a fourth vessel is coupled to the third module to provide LNG storage.

A distillation column is constituted by a cylindrical shell which contains mass and heat transfer elements and which is closed at one end by a cap and at the other end by a domed bottom and a cylindrical skirt that has the same diameter as the cylindrical shell, is aligned coaxially with the cylindrical shell and is fixed to one end of the cylindrical shell so as to surround the domed bottom, forming a space between the bottom, the walls of the skirt and a base, the skirt comprising at least one opening to allow the passage of a flushing gas.

One aspect of the invention relates to a hydrocarbons fluid liquefaction system, having a first heat-exchange module having a pre-cooling exchanger having a pre-cooling circuit and a plurality of pre-cooling refrigerant circuits for pre-cooling the feed stream through the circulation of an expanded first mixed-refrigerant stream, and a second heat-exchange module having a liquefaction exchanger having a liquefaction circuit and a liquefaction refrigerant circuit for liquefying the feed stream through the circulation of an expanded second mixed-refrigerant stream, wherein each heat-exchange module has thermally insulating walls and a framework that allows the module to be transported and secured, and allows the first heat-exchange module to be stacked on top of the second heat-exchange module.

Provided is a method of constructing a natural gas liquefaction plant, which can shorten a construction time period by minimizing effect of a lead time for the refrigerant compressor thereon, the method including: transporting a refrigerant compression module body 175 to an installation area 85, wherein the refrigerant compression module body is provided with a frame 120 configured to allow refrigerant compressor 150 for compressing a refrigerant for cooling natural gas to be mounted therein; installing the refrigerant compression module body 175 to the installation area 85; and mounting the refrigerant compressor 150 into a mounting space 130 predefined in the frame 120 of the installed refrigerant compression module body.

A dual-mode LNG liquefier arrangement that is configurable to operate in a first mode broadly characterized as a low pressure, liquid nitrogen add LNG liquefier without turbo-expansion or a second mode broadly characterized as a low pressure, liquid nitrogen add LNG liquefier with turbo-expansion.

To reduce work at an installation site when a plant facility is manufactured, modules are conveyed in order from a fabrication yard to the installation site, and expansion and contraction amounts of pipe spools are calculated based on a temperature difference between a temperature at the fabrication yard when the modules are manufactured and a temperature at the installation site when the modules are installed at the installation site. Further, an installation position of a foundation is adjusted toward a direction to cancel out the expansion and contraction amounts of the plurality of pipe spools, and the pipe spool is moved toward the direction to cancel out the expansion and contraction amounts of the plurality of pipe spools. The modules are installed with the positions of the end portions of the pipe spools being adjusted.

A system for removing acid gases from a raw gas stream is provided. The system includes a cryogenic distillation column. The cryogenic distillation column receives a dehydrated and chilled sour gas stream, and separates the sour gas stream into an overhead gas stream comprised primarily of methane, and a bottom acid gas stream comprised primarily of carbon dioxide. The system also includes a series of co-current contactors. The co-current contactors may be placed in series to receive the bottom acid gas stream and recapture any entrained methane gas. Alternatively or in addition, the co-current contactors may be placed in series to receive the overhead gas stream, and sweeten it using a reflux liquid such as methane. In this instance, the sweetened gas is optionally liquefied and delivered for commercial sale, or is used as fuel gas on-site.

Disclosed in the present invention are a cold box steel structure and method for prefabricating and transporting the cold box steel structure. The cold box steel structure is a cuboid architecture, and has a long edge, a wide edge and a high edge of lengths L, W and H respectively, wherein L>W and L>H; the cold box steel structure comprises first and second rectangular base faces, each being an outer surface of the cuboid architecture comprising the long edge and the wide edge, and the cold box steel structure is prefabricated as two partial components taking a plane parallel to the rectangular base faces as a boundary; the total height of a first partial cold box steel structure component thereof, taking the first rectangular base face as a first transportation bottom face, is h1, and the total height of a second partial cold box steel structure component, taking the second rectangular base face as a second transportation bottom face, is h2; if the height difference between the transportation bottom face and the ground or a water surface is h, then (h1+h) corresponds to a transportation height of the first partial cold box steel structure component, and (h2+h) corresponds to a transportation height of the second partial cold box steel structure component; the transportation height of either of the cold box steel structure components should be smaller than a maximum permitted transportation height h.sub.max.

An intelligent controls system for a field-deployable system for producing dry natural gas (NG) and natural gas liquids (NGLs) from a raw gas stream is disclosed. The control system is used to ensure correct specifications of both dry NG (above a desired minimum methane number) and NGLs (below a desired maximum vapor pressure) from any supplied raw natural gas source by controlling three system parameters: inlet gas flow rate, system operating pressure, and separator-reboiler temperature set point. The input parameters include: heat content of the input gas stream, volume of the input gas stream, desired methane number of the NG, and desired vapor pressure of the NGLs. The controls system allows any piece of remote field equipment for performing complex chemical processing to be monitored, controlled, and operated remotely. A large array of distributed field equipment situated around the world can all be controlled primarily through a single interface provided in a central control center.