摘要:
The invention relates to a natural gas liquefaction process and particularly to one suited to use offshore. The invention provides a natural gas liquefaction apparatus wherein a carbon dioxide based pre-cooling circuit is provided in a cascade arrangement with a main cooling circuit. The invention also extends to a natural gas liquefaction apparatus wherein a main cooling circuit uses as a refrigerant a gas stream, at least a portion of which is derived from a raw natural gas source.
摘要:
A method for liquefying a natural gas stream is provided. In one embodiment, the method includes placing a mixed component refrigerant in a heat exchange area with a process stream; separating the mixed component refrigerant at one or more pressure levels to produce a refrigerant vapor and a refrigerant liquid; bypassing the refrigerant vapor around the heat exchange area to a compression unit; and passing the refrigerant liquid to the heat exchange area. In another embodiment, the method further includes partially evaporating the refrigerant liquid stream within the heat exchange area to retain a liquid fraction of at least 1% by weight.
摘要:
Method for gas liquefaction comprising cooling a feed gas by a first refrigeration system in a first heat exchange zone and withdrawing a substantially liquefied stream therefrom, further cooling the substantially liquefied stream by indirect heat exchange with one or more work-expanded refrigerant streams in a second heat exchange zone, and withdrawing therefrom a further cooled, substantially liquefied stream. At least one of the one or more work-expanded refrigerant streams is provided by compressing one or more refrigerant gases to provide a compressed refrigerant stream, cooling all or a portion of the compressed refrigerant stream in a third heat exchange zone to provide a cooled, compressed refrigerant stream, and work expanding the cooled, compressed refrigerant stream to provide one of the one or more work-expanded refrigerant streams. The flow rate of a work-expanded refrigerant stream in the second heat exchange zone typically is less than the total flow rate of one or more work-expanded refrigerant streams in the third heat exchange zone.
摘要:
In a process for separating air in a system comprising a gas turbine, including a compressor (1), a combustor (5) and an expander (17), said expander being coupled to the compressor, a natural gas conversion unit (23) and an air separation unit (20), air is compressed in the compressor, a first part (3) of the air is sent to the combustor and a second part (7) of the air is sent to the air separation unit, oxygen enriched gas (21) is sent from the air separation unit to the natural gas conversion unit, compressed nitrogen enriched gas (16) is sent upstream of the expander, a first stream (33) of natural gas is sent to the natural gas conversion unit, a second stream of natural gas (35) is sent to a natural gas liquefaction unit and work produced by the expander is used to operate a cycle compressor of a refrigeration cycle of the natural gas liquefaction unit.
摘要:
A pretreatment system for natural gas liquefaction employing heat integration for more efficient and effective natural gas temperature control. The pretreatment system expands the natural gas prior to acid gas removal. After acid gas removal, the natural gas is cooled by indirect heat exchange with the expanded natural gas located upstream of the acid gas removal system.
摘要:
The invention relates to a natural gas liquefaction process and particularly to one suited to use offshore. The invention provides a natural gas liquefaction apparatus wherein a carbon dioxide based pre-cooling circuit is provided in a cascade arrangement with a main cooling circuit. The invention also extends to a natural gas liquefaction apparatus wherein a main cooling circuit uses as a refrigerant a gas stream, at least a portion of which is derived from a raw natural gas source.
摘要:
A method of gas liquefaction wherein the refrigeration to cool and liquefy an essentially water-free feed gas is provided by a single recirculating mixed refrigerant cycle in which refrigeration is provided by the vaporization of two mixed refrigerant streams of different compositions at a lower and higher pressure levels respectively. A lower pressure level vaporizing refrigerant cools the feed gas stream in a first cooling zone and a higher pressure level vaporizing refrigerant further cools and condenses the cooled gas in a second cooling zone to provide the final liquid product. The lower pressure level vaporizing refrigerant is provided by one or more liquids obtained by ambient cooling of compressed mixed refrigerant vapor. The vaporized lower pressure level refrigerant can be returned to the refrigerant compressor at a temperature below ambient, without further warming, and this cool refrigerant is compressed and combined with the vaporized higher pressure level refrigerant, which is returned at about ambient temperature.
摘要:
Process and system for liquefying a pressurized gas, especially natural gas. The process is carried out in two heat exchangers, and cooling for each heat exchanger is provided by a mixed refrigerant which is vaporized at a single essentially constant pressure. Feed precooling, low level refrigerant precooling, and high level liquid refrigerant subcooling are effected in one of the heat exchanger against low level refrigerant vaporizing at a single essentially constant pressure. The process and system of the invention are especially well-suited for installation on ships, barges, and offshore platforms.
摘要:
The invention is a process for liquefying a compound A from a mixture comprising at least compound A and at least one compound B. The mixture is available at a pressure P1 with separation of the at least one compounds B and/or of compound A being performed by distillation at a pressure substantially close to pressure P2 in order to produce at least a stream mainly comprising the compound A and at least a stream F4 comprising most of the at least one compound B. The invention has an application of methane and/or helium extraction during liquefaction of a natural gas.
摘要:
A method allowing a gaseous mixture such as a natural gas to be liquefied by using a first compressed coolant mixture M.sub.1, at least partially condensed by cooling with the aid of an external coolant fluid, then subcooled, expanded, and vaporized, and a second compressed coolant mixture, cooled with the aid of an external coolant fluid, then cooled by heat exchange with the first coolant mixture M.sub.1 during the first cooling stage (I), after which it is in an at least partially condensed state. The second partially condensed coolant mixture is sent without phase separation to a second cooling stage (II) where it is fully condensed, expanded, and vaporized at at least two pressure levels. The subcooled natural gas is expanded to form the LNG produced.