JP6338589B2 - Natural gas liquefaction - Google Patents

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a benefit of US Provisional Patent Application No. 61 / 727,577 filed November 16, 2012, which is the title of the invention of natural gas liquefaction, which is incorporated herein by reference in its entirety. Is an insistence.

  The technology of the present invention relates generally to the field of hydrocarbon recovery and treatment processes, and more particularly via a refrigeration process that includes two fluorocarbon refrigeration cycles upstream of a nitrogen refrigeration cycle or a methane auto refrigeration cycle. The present invention relates to a method and system for forming liquefied natural gas (LNG).

This section is intended to outline various aspects of the art that may be associated with exemplary embodiments of the present technology. This discussion is believed to help provide a framework for facilitating a better understanding of certain aspects of the technology of the present invention. Therefore, it should be understood that this section should be read from this perspective and not necessarily as an admission for the prior art.
Many low temperature refrigeration systems used for natural gas processing and liquefaction rely on providing refrigerants containing hydrocarbon components and nitrogen to provide external refrigeration. Examples of such hydrocarbon components include methane, ethane, ethylene, propane, and the like. However, in many cases, it is desirable to provide a refrigeration system that uses a non-flammable refrigerant.
Foglietta et al., US Pat. No. 6,412,302, describes a process for producing a liquefied natural gas stream. The process includes cooling at least a portion of the pressurized natural gas feed stream by heat exchange contact with first and second expanded refrigerants used in independent refrigeration cycles. The first expanded refrigerant is selected from methane, ethane, and natural gas that has been treated and pressurized, and the second expanded refrigerant is nitrogen. However, as discussed herein, it may be desirable to generate an LNG stream in a refrigeration system that uses a non-flammable refrigerant.

One embodiment provides a hydrocarbon processing system for forming liquefied natural gas (LNG). The hydrocarbon treatment system includes a first fluorocarbon refrigeration system configured to cool a natural gas using a first fluorocarbon refrigerant, and a natural gas using a second fluorocarbon refrigerant. A second fluorocarbon refrigeration system configured to further cool the refrigeration. The hydrocarbon treatment system also includes a nitrogen refrigeration system configured to cool natural gas using nitrogen refrigerant to produce LNG, and a nitrogen removal unit configured to remove nitrogen from the LNG including.
Another embodiment provides a method for forming LNG. The method includes the steps of: cooling the natural gas with a first fluorocarbon refrigeration system; cooling the natural gas with a second fluorocarbon refrigeration system; and liquefying the natural gas with a nitrogen refrigeration system. Forming and removing nitrogen from the LNG with a nitrogen removal unit.
Another embodiment provides a hydrocarbon processing system for forming LNG. The hydrocarbon treatment system includes a first refrigeration system configured to cool the natural gas using a first fluorocarbon refrigerant, the first refrigeration system including the natural gas and the first refrigeration system. It includes a number of first heat exchangers configured to cool natural gas through indirect heat exchange with a fluorocarbon refrigerant. The hydrocarbon treatment system includes a second refrigeration system configured to cool the natural gas using a second fluorocarbon refrigerant, the second refrigeration system including the natural gas and the second fluorine. A number of second heat exchangers configured to be capable of cooling natural gas via indirect heat exchange with the carbonized refrigerant. The hydrocarbon treatment system also includes a third refrigeration system configured to form LNG from natural gas using a nitrogen refrigerant, the third refrigeration system comprising a natural gas and a nitrogen refrigerant. A number of third heat exchangers configured to be able to cool the natural gas through indirect heat exchange. The hydrocarbon treatment system further includes a nitrogen removal unit configured to remove nitrogen from the LNG.

  Another embodiment provides a hydrocarbon processing system for forming LNG. The hydrocarbon treatment system includes a first fluorocarbon refrigeration system configured to cool a natural gas using a first fluorocarbon refrigerant, and a natural gas using a second fluorocarbon refrigerant. A second fluorocarbon refrigeration system configured to further cool, and an automatic methane refrigeration system configured to cool natural gas to produce LNG.

  The advantages of the techniques of the present invention will be better understood with reference to the following detailed description and accompanying drawings.

It is a process flow figure of a single stage refrigeration system. FIG. 2 is a process flow diagram of a two-stage refrigeration system including an economizer. FIG. 2 is a process flow diagram of a single stage refrigeration system including a heat exchanger saving device. FIG. 3 is a process flow diagram of a cascade cooling system including a first refrigeration system and a second refrigeration system. It is a process flow figure of an expansion refrigeration system for controlling a dew point of hydrocarbon. FIG. 2 is a process flow diagram of an expansion refrigeration system for generating NGL. It is a process flow figure of an LNG generation system. It is a process flow figure of a cascade fluorocarbon and a nitrogen refrigeration cooling system. It is a process flow figure of a cascade fluorocarbon and a nitrogen refrigeration cooling system. FIG. 9 is a process flow diagram of a system including NRU. FIG. 6 is a process flow diagram of another cascaded fluorocarbon and nitrogen refrigeration cooling system. FIG. 6 is a process flow diagram of another cascaded fluorocarbon and nitrogen refrigeration cooling system. FIG. 6 is a process flow diagram of an alternative embodiment of a cascaded fluorocarbon, nitrogen refrigeration cooling system and a simplified nitrogen refrigeration system. FIG. 6 is a process flow diagram of another cascade cooling system. FIG. 6 is a process flow diagram of another cascade cooling system. FIG. 12 is a process flow diagram of an automatic refrigeration system provided within the same hydrocarbon treatment system as the cascade cooling system of FIGS. 11A and 11B. FIG. 2 is a process flow diagram of a method for forming LNG from a natural gas stream. FIG. 4 is a process flow diagram of another method for forming LNG from a natural gas stream.

In the following detailed description section, specific embodiments of the technology of the present invention are described. However, this embodiment is intended to be illustrative only to the extent that the following description is specific to one particular embodiment or one particular use of the technology of the present invention, The exemplary embodiments are merely described. Accordingly, the technology of the invention is not limited to the specific embodiments described herein, but includes all alternatives, modifications and equivalents that fall within the spirit and scope of the appended claims.
First, for ease of reference, certain terms used in this application and their meanings used in this context will be described. Where a term used herein is not defined herein, that term is the most given to those terms by those skilled in the art as represented in at least one publication or issued patent. A broad definition should be given. Further, the techniques of the invention are not limited by the usage of the terms set forth herein, and any equivalents, synonyms, new developments, and terms or techniques that serve the same or similar purposes are It is understood that it falls within the scope of the claims.

As used herein, “automatic refrigeration” refers to a process in which a portion of the product stream is used for refrigeration purposes. Automatic refrigeration is achieved by extracting a fraction of the product stream prior to final cooling in order to provide refrigeration capacity. This extracted stream expands in a valve or inflator, and as a result of the expansion, the temperature of the stream decreases. This stream is used to cool the product stream in a heat exchanger. After heat exchange, this stream is recompressed and blended with the feed gas stream. This process is also known as open cycle refrigeration.
Alternatively, “automatic refrigeration” refers to the process by which a fluid is cooled via a pressure drop. In the case of a liquid, automatic refrigeration refers to the liquid being cooled by evaporation corresponding to a pressure drop. More specifically, a portion of the liquid undergoes a pressure drop as it passes through the throttling device, thus flashing into vapor. As a result, both vapor and residual liquid are cooled to the liquid saturation temperature under reduced pressure. For example, according to the embodiments described herein, the automatic refrigeration of natural gas is performed by maintaining the natural gas at its boiling point and thus cooling the natural gas with loss of heat during boil-off. be able to. This process can also be referred to as “flash evaporation”.

As used herein, “cascade cycle” refers to a system that uses two or more refrigerants, where the cooled second refrigerant is condensed by the warmer first refrigerant. Thus, low temperatures can be transmitted in a “cascade fashion” from one refrigerant to another. Each refrigerant in the cascade can be provided with multiple levels of cooling based on the stepwise evaporation pressure in the economizer. It is understood that cascade cycles are beneficial for the production of LNG compared to single refrigerant systems, since lower temperatures can be achieved within a cascade cycle than single refrigerant systems.
A “compressor” or “refrigerant compressor” includes any unit, device, or apparatus that can increase the pressure of a refrigerant stream. This includes refrigerant compressors having a single compression process or step, or refrigerant compressors having multi-stage compression or steps, and more particularly multi-stage refrigerant compressors in a single casing or shell including. The evaporated refrigerant stream to be compressed can be provided to different pressure refrigerant compressors. Some stages or steps of the hydrocarbon cooling process may include two or more refrigerant compressors in parallel, in series, or both. The present invention is not limited by the type or arrangement or layout of one or more refrigerant compressors, particularly in any refrigerant circuit.

  As used herein, “cooling” broadly refers to the reduction and / or reduction of a material's temperature and / or internal energy, eg, by any suitable amount. Cooling may include a temperature decrease such as at least about 1 ° C., at least about 5 ° C., at least about 10 ° C., at least about 15 ° C., at least about 25 ° C., at least about 50 ° C., at least about 100 ° C. Any suitable heat sink may be used for cooling, such as steam generation, hot water heating, cooling water, air, refrigerant, other process streams (integrated), and combinations thereof. One or more sources of cooling can be combined and / or cascaded to obtain the desired outlet temperature. In the cooling step, a cooling unit with any suitable device and / or apparatus can be used. According to one embodiment, cooling may include indirect heat exchange, such as by one or more heat exchangers. The heat exchanger can include any suitable design, such as shells and tubes, brazed aluminum, spirals, and the like. Alternatively, the cooling can use evaporation (heat of vaporization) cooling, sensible heat cooling, and / or direct heat exchange, for example liquid sprayed directly into the process stream.

“Cryogenic” refers to temperatures below about −50 ° C.
As used herein, the terms “deethanizer” and “demethanizer” refer to a distillation column or tower that can be used to separate components in a natural gas stream. For example, demethanizer towers are used to separate methane and other volatile components from ethane and heavier components. The methane fraction is typically recovered as a purified gas containing a small amount of inert gas such as nitrogen, CO _{2 and the} like.

“Fluorocarbon”, also called “perfluorocarbon” or “PFC”, is a molecule containing F and C atoms. Fluorocarbon has an F—C bond and has a C—C bond depending on the number of carbon atoms of the chemical species. An example of fluorocarbon is hexafluoroethane (C ₂ F ₆ ). “Hydrofluorocarbon” or “HFC” is a specific type of fluorocarbon containing H, F and C atoms. Hydrofluorocarbons have H—C and F—C bonds, and have C—C bonds depending on the number of carbon atoms in the chemical species. Some examples of hydrofluorocarbons include fluoroform (CHF ₃ ), pentafluoroethane (C ₂ HF ₅ ), tetrafluoroethane (C ₂ H ₂ F ₄ ), among other compounds of similar chemical structure, Examples include heptafluoropropane (C ₃ HF ₇ ), hexafluoropropane (C ₃ H ₂ F ₆ ), pentafluoropropane (C ₃ H ₃ F ₅ ), and tetrafluoropropane (C ₃ H ₄ F ₄ ).

The term “gas” is used interchangeably with “vapor” and is defined as a gaseous substance or substance mixture that is distinct from the liquid or solid state. Similarly, the term “liquid” means a substance or mixture of substances in a liquid state that is distinguished from a gas or solid state.
“Heat exchanger” refers broadly to any device that can transfer heat from one medium to another, particularly including any structure, such as a device commonly referred to as a heat exchanger. Heat exchangers include “direct heat exchangers” and “indirect heat exchangers”. Therefore, heat exchangers are shell-and-tube, helix, hairpin, core, core-and-kettle, double tube, brazed aluminum, spiral, Or any other type of known heat exchanger. A “heat exchanger” allows one or more streams to pass through a heat exchanger for direct or indirect heat exchange between one or more lines of refrigerant and one or more feed streams. It can also refer to any column, tower, unit or other arrangement adapted to influence.

“Hydrocarbons” are organic compounds that primarily contain the elements hydrogen and carbon, although nitrogen, sulfur, oxygen, metals, or any number of other elements may be present in small amounts. As used herein, hydrocarbon generally refers to a component found in natural gas, oil, or chemical processing facilities.
“Liquefied natural gas” or “LNG” is a natural gas that is generally known to contain a high proportion of methane. However, LNG can also contain trace amounts of other compounds. Other elements or compounds can include, but are not limited to, ethane, propane, butane, carbon dioxide, nitrogen, helium, hydrogen sulfide, or combinations thereof, which include one or more components ( E.g. helium) or impurities (e.g. water and / or heavy hydrocarbons) are removed and then condensed into a liquid by cooling at approximately atmospheric pressure.

“Liquefied petroleum gas” or “LPG” generally refers to a mixture of propane, butane, and other light hydrocarbons obtained by refining crude oil. At normal temperature, LPG is a gas. However, LPG can be cooled or pressured to facilitate storage and transportation.
A “mixed refrigerant process” can include a single refrigeration system, a hydrocarbon pre-cooled mixed refrigerant system, and a dual mixed refrigerant system that use a mixed refrigerant, ie, a refrigerant that includes two or more chemical components. It is not limited. In general, the mixed refrigerant can include hydrocarbon and / or non-hydrocarbon components. Examples of suitable hydrocarbon components typically used in mixed refrigerants include, but are not limited to, methane, ethane, ethylene, propane, propylene, butane and butylene isomers, and pentane. Nitrogen can be mentioned as a non-hydrocarbon component generally used for a mixed refrigerant. The mixed refrigerant process uses at least one mixed component refrigerant, although one or more pure component refrigerants can be used as well.

“Natural gas” refers to a multi-component gas obtained from a crude oil well or from an underground gas-bearing formation. The composition and pressure of natural gas can vary significantly. A typical natural gas stream contains methane (CH ₄ ) as a major component, ie, more than 50 mol% of the natural gas stream is methane. The natural gas stream may be ethane (C ₂ H ₆ ), higher molecular weight hydrocarbons (eg C ₃ -C ₂₀ hydrocarbons), one or more acid gases (eg carbon dioxide or hydrogen sulfide), or In some cases. Natural gas may also contain small amounts of contaminants such as water, nitrogen, iron sulfide, waxy substances, crude oil, or any combination thereof. The natural gas stream can be substantially purified prior to use in embodiments to remove compounds that can act as poisons or freeze during the cooling process.

As used herein, “natural gas liquid” (NGL) refers to a mixture of hydrocarbons whose components are typically heavier than methane and condensed from natural gas, for example. . Some examples of the hydrocarbon component of the NGL stream include ethane, propane, butane, and pentane isomers, benzene, toluene, and other aromatic compounds.
The “nitrogen removal unit” or “NRU” accepts a natural gas feed stream and produces a substantially pure product stream, such as a methane stream that can be sold and a nitrogen stream comprising about 30% to 99% N _2. Refers to any system or device configured. Examples of NRU types include cryogenic distillation, pressure swing adsorption (PSA), membrane separation, lean oil absorption, and solvent absorption.
The “refrigerant component” in the refrigeration system absorbs heat at a lower temperature and pressure via evaporation and exhausts heat at a higher temperature and pressure via condensation. Exemplary refrigerant components include alkanes, alkenes and alkynes having 1 to 5 carbon atoms, nitrogen, chlorinated hydrocarbons, fluorinated hydrocarbons, other halogenated hydrocarbons, noble gases, and mixtures or combinations thereof But are not limited to these.

  The refrigerant component often includes a single component refrigerant. Single component refrigerants containing a single halogenated hydrocarbon have an associated “R-” symbolic representation of two or three numbers that reflects the chemical composition of the refrigerant. Adding 90 to that number results in three digits representing the number of carbon, hydrogen, and fluorine atoms, respectively. The first digit of a refrigerant with three numbers is one unit less than the number of carbon atoms in the molecule. If the molecule contains only one carbon atom, the first digit is omitted. The second digit is one unit greater than the number of hydrogen atoms in the molecule. The third digit is equal to the number of fluorine atoms in the molecule. The remaining bonds not described are occupied by chlorine atoms. The suffix “a”, “b” or “c” in lower case indicates that the asymmetry of the isomer is increased. As a special case, the R-400 series consists of non-azeotropic blends and the R-500 series consists of so-called azeotropic blends. The rightmost digit is arbitrarily assigned by ASHRAE, which is an industrial organization.

“Substantial”, when used in reference to the content or amount of a material, or a particular characteristic of a material, refers to an amount sufficient to produce the effect intended to be provided by the material or characteristic. . The exact allowable deviation may vary depending on the specific context in some cases.
Overview Embodiments described herein provide a hydrocarbon processing system. The hydrocarbon processing system includes a refrigeration system, such as a cascade cooling system, to produce LNG from natural gas. The refrigeration system includes two fluorocarbon refrigeration systems and a nitrogen or methane refrigeration system. Fluorocarbon refrigeration systems and nitrogen or methane refrigeration systems are used to cool natural gas to produce LNG. Further, the hydrocarbon processing system can include NRU, which can be used to remove nitrogen from the produced LNG.

The hydrocarbon treatment system includes any number of systems known to those skilled in the art. Hydrocarbon generation and treatment processes include cooling natural gas to extract NGL, cooling natural gas to control hydrocarbon dew point, cooling natural gas to remove CO ₂ , LPG Production and storage, condensation of reflux in a deethanizer / demethanizer, and liquefaction of natural gas to produce LNG.
Many refrigeration cycles are used to treat hydrocarbons, but one cycle used in an LNG liquefaction facility is a cascade cycle, in which the temperature of the gas is gradually reduced to the liquefaction temperature. In the heat exchanger arranged in the above, a plurality of single component refrigerants are used. Another cycle used in the LNG liquefaction facility is a multi-component refrigeration cycle, which uses a multi-component refrigerant in a specially designed exchanger. In addition, another cycle used in the LNG liquefaction facility is the expander cycle, in which the gas is reduced from the supply gas pressure to expand with a corresponding temperature drop. Natural gas liquefaction cycles may use variations or combinations of these three cycles.

LNG is prepared from feed gas by refrigeration and liquefaction techniques. Optional steps include condensate removal, CO ₂ removal, dehydration, mercury removal, nitrogen removal, H ₂ S removal, and the like. Once LNG is liquefied, it can be stored or loaded into a tanker for sale or transportation. Typical liquefaction processes include: APCI Propane precooled mixed refrigerant; C3MR; DUAL MR; Phillips Optimized Cascade; Prico single mixed refrigerant; TEAL dual pressure mixed refrigerant; Linde / Statoil multifluid cascade; Axens double mixed refrigerant, DMR; Mention may be made of the Shell processes C3MR and DMR.
Carbon dioxide removal, ie separation of methane and lighter gases from CO ₂ and heavier gases, can be achieved using a cryogenic distillation process such as the Controlled Freeze Zone technology available from ExxonMobil Corporation. .

Although the methods and systems described herein are discussed with respect to the formation of LNG from natural gas, the methods and systems can also be used for a variety of other purposes. For example, the methods and systems described herein, among other things, cool natural gas to control the dew point of hydrocarbons, perform extraction of natural gas liquids (NGL), and from carbon dioxide and heavier gases. It can be used to separate methane and lighter gases, prepare hydrocarbons to produce LPG, or condense the reflux stream in a deethanizer and / or demethanizer.
Refrigerant The refrigerant utilized in accordance with the embodiments described herein may be a single component, one or more refrigerants, or a refrigerant mixture comprising multiple components. The refrigerant can be imported and stored in situ, or some of the components of the refrigerant can be prepared in situ, typically by a distillation process integrated with a hydrocarbon treatment system. Commercially available refrigerants including fluorocarbon (FC) or hydrofluorocarbon (HFC) are used in various applications. Exemplary refrigerants are commercially available from DuPont Corporation, including the ISCEON® family of refrigerants, the SUVA® family of refrigerants, the OPTEON® family of refrigerants, and the FReon® family of refrigerants. Has been.

  Multicomponent refrigerants are commercially available. For example, R-401A is an HCFC blend of R-32, R-152a, and R-124. R-404A is an HFC blend of 52 wt% R-143a, 44 wt% R-125, and 4 wt% R-134a. R-406A is a blend of 55 wt% R-22, 4 wt% R-600a, and 41 wt% R-142b. R-407A is an HFC blend of 20 wt% R-32, 40 wt% R-125, and 40 wt% R-134a. R-407C is a hydrofluorocarbon blend of R-32, R-125, and R-134a. R-408A is an HCFC blend of R-22, R-125, and R-143a. R-409A is an HCFC blend of R-22, R-124, and R-142b. R-410A is a blend of R-32 and R-125. R-500 is a blend of 73.8 wt% R-12 and 26.2 wt% R-152a. R-502 is a blend of R-22 and R-115. R-508B is a blend of R-23 and R-116.

In various embodiments, any of a number of different types of hydrocarbon processing systems can be used in conjunction with any of the refrigeration systems described herein. Furthermore, any of the refrigerants described in this specification may be used in the refrigeration system described in this specification.
Refrigeration systems Hydrocarbon systems and methods often include refrigeration systems that utilize mechanical refrigeration, valve expansion, turbine expansion, and the like. Mechanical refrigeration typically includes a compression system and an absorption system, such as an ammonia absorption system. Compression systems are used in various processes in the gas processing industry. For example, a compression system can cool natural gas to extract NGL, cool natural gas to control hydrocarbon dew point, LPG production and storage, reflux condensation in deethanizer or demethanizer tower, It can be used for liquefaction of natural gas to produce LNG.

  FIG. 1 is a process flow diagram of a single stage refrigeration system 100. In various embodiments, the single stage refrigeration system 100 utilizes a refrigerant such as fluorocarbon. Further, in various embodiments, the single stage refrigeration system 100 is implemented upstream of a nitrogen refrigeration or methane automatic refrigeration system that includes an NRU. A plurality of single stage refrigeration systems 100 can also be implemented in series upstream of such a nitrogen refrigeration system or an automatic methane refrigeration system.

  Single stage refrigeration system 100 includes an expansion valve 102, a chiller 104, a compressor 106, a condenser 108, and an accumulator 110. The saturated liquid refrigerant 112 can flow from the accumulator 110 to the expansion valve 102 and can pass through the expansion valve 102 and expand with equal enthalpy. Upon expansion, some vaporization can occur, resulting in a chilled refrigerant mixture 114 containing both vapor and liquid. The refrigerant mixture 114 can enter a cooling device 104, also known as an evaporator, at a temperature below that at which the process stream 116, such as natural gas, is to be cooled. The process stream 116 flows through the cooling device 104 and exchanges heat with the refrigerant mixture 114. The process stream 116 is cooled upon heat exchange with the refrigerant mixture 114, and the refrigerant mixture 114 vaporizes to produce a saturated vapor refrigerant 118.

The saturated vapor refrigerant 118 exits the cooling device 104 and is then compressed in the compressor 106 and then flows to the condenser 108. Within the condenser 108, the saturated vapor refrigerant 118 is converted to a saturated or slightly subcooled liquid refrigerant 120. The liquid refrigerant 120 can then flow from the condenser 108 to the accumulator 110. Accumulator 110, also known as a surge tank or receiver, can serve as a reservoir for liquid refrigerant 120. After being stored in the accumulator 110, the liquid refrigerant 120 can be expanded as a saturated liquid refrigerant 112 through the expansion valve 102.
It should be understood that the process flow diagram of FIG. 1 does not indicate that the single stage refrigeration system 100 should include any of the components shown in FIG. Further, the single stage refrigeration system 100 may include any number of additional components not shown in FIG. 1 depending on the particular implementation details. For example, in some embodiments, the refrigeration system can include more than one compression stage. Further, the refrigeration system 100 can include a saver, as further discussed with respect to FIG.

FIG. 2 is a process flow diagram of a two-stage refrigeration system 200 that includes a savings device 202. The numbered items are the same as those described with respect to FIG. In various embodiments, the two-stage refrigeration system 200 utilizes a refrigerant such as fluorocarbon. Further, in various embodiments, the two-stage refrigeration system 200 is implemented upstream of a nitrogen refrigeration or methane automatic refrigeration system that includes an NRU. A plurality of two-stage refrigeration systems 200 can also be implemented in series upstream of such a nitrogen refrigeration system or an automatic methane refrigeration system.
The saver 202 can be any device or process modification that reduces the compressor power usage required for a given chiller. Typical saving devices 202 include, for example, flash tanks and heat exchange saving devices. Heat exchange conserving devices utilize multiple heat exchangers to transfer heat between process streams. Thereby, the energy input amount to the two-stage refrigeration system 200 can be reduced by thermally integrating the process streams with each other.

  As shown in FIG. 2, the saturated liquid refrigerant 112 exiting the accumulator 110 can be expanded through a moderate pressure expansion valve 102 from which vapor and liquid can be separated. For example, when the saturated liquid refrigerant 112 flushes through the expansion valve 102, vapor refrigerant 204 and liquid refrigerant 206 are generated at a lower pressure and temperature than the saturated liquid refrigerant 112. The vapor refrigerant 204 and liquid refrigerant 206 can then flow to the economizer 202. In various embodiments, the economizer 202 is a flash tank that separates the vapor refrigerant 204 and the liquid refrigerant 206. The vapor refrigerant 204 can flow to a medium pressure compressor stage where the vapor refrigerant 204 combines with the saturated vapor refrigerant 118 exiting the first compressor 210 to produce a mixed saturated vapor refrigerant 208. Can do. The mixed saturated vapor refrigerant 208 can then flow to the second compressor 212.

The liquid refrigerant 206 derived from the saving device 202 can be expanded by isoenthalpy through the second expansion valve 214. Upon expansion, some vaporization occurs, producing a refrigerant mixture 216 that includes both vapor and liquid, which can reduce temperature and pressure.
Cooling mixture 216 will have a high liquid content than the refrigerant mixture in the system without the economizer. A higher liquid content can reduce the refrigerant circulation rate and / or reduce the power usage of the first compressor 210.
The refrigerant mixture 216 enters a cooling device 104, also known as an evaporator, at a temperature below that at which the process stream 116 is to be cooled. Process stream 116 is cooled in chilling apparatus 104 as discussed with respect to FIG. Further, saturated vapor refrigerant 118 flows through compressors 210 and 212 and condenser 108 and the resulting liquid refrigerant 120 is stored in accumulator 110 as discussed with respect to FIG.

It should be understood that the process flow diagram of FIG. 2 does not indicate that the two-stage refrigeration system 200 should include any of the components shown in FIG. Further, the two-stage refrigeration system 200 can include any number of additional components not shown in FIG. 2, depending on the particular implementation details. For example, the two-stage refrigeration system 200 can include any number of additional saving devices or other types of devices not shown in FIG. Further, the saving device 200 may be a heat exchange saving device instead of a flash tank. The heat exchange conserving device can also be used to reduce refrigeration circulation rate and reduce compressor power usage.
In some embodiments, the two-stage refrigeration system 200 includes two or more conserving devices 202 and three or more compressors 210 and 212. For example, the two-stage refrigeration system 200 can include two conserving devices and three compressors. In general, if the refrigeration system 200 includes X conserving devices, the refrigeration system 200 includes X + 1 compressors. Such a refrigeration system 200 that includes multiple saving devices can form part of a cascade refrigeration system.

FIG. 3 is a process flow diagram of a single stage refrigeration system 300 that includes a heat exchanger conserving device 302. The numbered items are the same as those described with respect to FIG. In various embodiments, the single stage refrigeration system 300 utilizes a refrigerant such as fluorocarbon. Further, in various embodiments, the single stage refrigeration system 300 is implemented upstream of a nitrogen refrigeration system including an NRU or a methane automatic refrigeration system. Multiple single stage refrigeration systems 300 can also be implemented in series upstream of such nitrogen refrigeration systems or methane automatic refrigeration systems.
As shown in FIG. 3, the saturated liquid refrigerant 112 exiting the accumulator 110 is expanded through a moderate pressure expansion valve 102 from which vapor and liquid can be separated to produce a refrigerant mixture 114. can do. The refrigerant mixture 114 can flow to the chiller 104 at a temperature that is lower than the temperature at which the process stream 116 is to be cooled. Process stream 116 may be cooled in chiller 104 as discussed with respect to FIG.

Saturated vapor refrigerant 118 originating from the cooling device 104 can flow through the heat exchanger conserving device 302. The cooled low pressure saturated vapor refrigerant 118 can be used to subcool the saturated liquid refrigerant 112 in the heat exchanger conserving device 302. Next, the superheated vapor refrigerant 304 leaving the heat exchanger conserving device 302 can flow through the compressor 106 and the condenser 108 and the resulting liquid refrigerant 120 is as discussed with respect to FIG. Can be stored in the accumulator 110.
It should be understood that the process flow diagram of FIG. 3 does not indicate that the single stage refrigeration system 300 should include any of the components shown in FIG. Further, the single stage refrigeration system 300 can include any number of additional components not shown in FIG. 3, depending on the particular implementation details.

  FIG. 4 is a process flow diagram of a cascade cooling system 400 that includes a first refrigeration system 402 and a second refrigeration system 404. In various embodiments, the first refrigeration system 402 and the second refrigeration system 404 utilize a fluorocarbon refrigerant. For example, R-410A can be used in the first refrigeration system 402, and R-508B can be used in the second refrigeration system 404. Further, the refrigerant of either refrigeration system 402 or 404 can include a mixture. Cascade cooling system 400 may be used when a higher degree of cooling than that provided by refrigeration system 100, 200, or 300 is desired. The cascade cooling system 400 can perform cooling at a very low temperature, for example, less than −40 ° C. Further, in some embodiments, the cascade cooling system 400 is implemented upstream of a nitrogen refrigeration system or a methane auto refrigeration system.

  Within the first refrigeration system 402, the vapor / liquid refrigerant stream 406 can flow from the accumulator 408 through the first expansion valve 410 and the first heat exchanger 412, thereby producing a product stream 413. Is cooled. The resulting vapor stream is separated in a first flash drum 414. A portion of the vapor / liquid refrigerant stream 406 can flow directly to the first flash tank 414 via the bypass valve 416.

  The liquid refrigerant stream 418 originating from the first flash tank 414 flows through the second expansion valve 420 and can be flushed to the second heat exchanger 422, which is used to produce the product stream 413. Can be further cooled. The gas accumulator 424 supplies the resulting vapor refrigerant stream 426 to the first stage compressor 428. The resulting intermediate pressure vapor refrigerant stream 430 is combined with the vapor refrigerant stream 432 originating from the first flash tank 414 and the combined stream is fed to the second stage compressor 434. The high pressure vapor stream 436 from the second stage compressor 434 passes through the condenser 438 so that the cooling from the second refrigeration system 404 can be used. Specifically, the condenser 438 can use the cold refrigerant stream 440 derived from the second refrigeration system 404 to cool the high pressure vapor stream 436 to produce a liquid refrigerant stream 406. The liquid refrigerant stream 406 originating from the condenser 438 is then stored in the accumulator 408. The control valve 442 can be used to control the flow of the cryogenic refrigerant stream 440 through the condenser 438. The resulting vapor refrigerant stream 444 originating from the condenser 438 can flow back to the second refrigeration system 404.

Within the second refrigeration system 404, the liquid refrigerant stream 448 can flow from the accumulator 450 via a heat exchanger 452 that is configured to cool the liquid refrigerant stream 448 by a cooling system 454. The cooling system 454 can be implemented by heat exchanging with various process streams such as, for example, a natural gas stream exiting the final flash tank that separates NGL from the gas.
The resulting cold refrigerant stream 456 can flow through the first expansion valve 458 and the first heat exchanger 460, thereby cooling the product stream 413. The resulting vapor / liquid refrigerant stream is separated in the first flash tank 462. A portion of the cryogenic refrigerant stream 456 can flow directly to the first flash tank 462 via a bypass valve 464 that can be a level control valve for controlling the fluid entering the flash tank 462.

The liquid refrigerant stream 466 originating from the first flush tank 462 can flow through the second expansion valve 468 and can be flushed to the second heat exchanger 470, which is used to produce the product stream 413. Can be further cooled. The resulting vapor / liquid refrigerant stream is separated in the second flash tank 472. A portion of the liquid refrigerant stream 466 passes through the second flash tank 472 via a bypass valve 474 that can be used to control the temperature of the liquid in the second flash tank 472 and the amount of cooling in the second heat exchanger 470. Can flow directly.
The liquid refrigerant stream 476 originating from the second flash tank 472 flows through the third expansion valve 478 and can be flushed to the third heat exchanger 480, which is used to produce the product stream 413. Can be further cooled. The gas accumulator 482 supplies the resulting vapor refrigerant stream 484 to the first stage compressor 486. The resulting intermediate pressure vapor refrigerant stream 488 is combined with the vapor refrigerant stream 490 originating from the second flash tank 472 and the combined stream is fed to the second stage compressor 492. The resulting high pressure vapor refrigerant stream 494 is combined with the vapor refrigerant mixture 496 originating from the first flash tank 462 and the combined stream is fed to a third stage compressor 497. The resulting high pressure vapor refrigerant stream 498 flows via heat exchanger 499 where it can be further cooled via indirect heat exchange with cooling water. The resulting liquid refrigerant stream 448 can then flow to the accumulator 450.

It should be understood that the process flow diagram of FIG. 4 does not indicate that the cascade cooling system 400 should include any of the components shown in FIG. Further, the cascade cooling system 400 may include any number of additional components not shown in FIG. 4, depending on the particular implementation details.
FIG. 5 is a process flow diagram of an expansion refrigeration system 500 for controlling the dew point of hydrocarbons. Heavier hydrocarbons in the natural gas in the pipe, for example, condensation of C ₃ -C ₆ leads to liquid slugging in pipelines, which may result in disruption of the facility to receive the gas. Thus, the dew point of the hydrocarbon can be reduced using the expansion refrigeration system 500 to prevent such condensation.

As shown in FIG. 5, the dehydrated natural gas supply stream 502 can flow to a gas / gas heat exchanger 504. Within the gas / gas heat exchanger 504, the dehydrated natural gas feed stream 502 can be cooled via indirect heat exchange with the cold natural gas stream 506. The resulting natural gas stream 508 can flow to the first separator 510, thereby removing some amount of heavy hydrocarbons 512 from the natural gas stream 508. In various embodiments, removing heavy hydrocarbons 512 from natural gas stream 508 reduces the dew point of natural gas stream 508. The removed heavy hydrocarbon 512 can flow from the expansion refrigeration system 500 through the first outlet valve 514. For example, heavy hydrocarbons 512 can flow from the expansion refrigeration system 500 to a stabilization device (not shown).
Natural gas stream 508 can then flow to expander 516. In various embodiments, the expander 516 is a turbo expander that is a centrifugal or axial turbine. Expansion of the natural gas stream 508 within the expander 516 can provide energy to drive the compressor 518 that is coupled to the expander 516 via the shaft 520.

The resulting cold natural gas stream 506 from the expander 516 can flow to the second separator 522, thereby removing any remaining heavy hydrocarbons 512 from the cold natural gas stream 506. can do. In various embodiments, the removal of heavy hydrocarbons 512 from the cold natural gas stream 506 further reduces the dew point of the cold natural gas stream 506. The removed heavy hydrocarbon 512 can then flow out of the expansion refrigeration system 500 via the second outlet valve 524.
The cold natural gas stream 506 can flow from the second separator 522 to the gas / gas heat exchanger 504, thereby increasing the temperature of the cold natural gas stream 506 to produce a hot natural gas stream 526. be able to. The hot natural gas stream 526 can then flow through the compressor 518, thereby returning the pressure of the natural gas stream 526 to an acceptable commercial gas pressure. The final natural gas stream 528 with a reduced dew point can then flow out of the expanded refrigeration system 500.

In one embodiment, cooling can be added to the process using, for example, a cooling system that uses a fluorocarbon refrigerant and a nitrogen refrigerant. This cooling can be accomplished by placing a heat exchanger 530 in the natural gas stream 508 or the cold natural gas stream 506 upstream of the second separator 522. The refrigerant liquid 532 can be flushed via a device 530 that cools through the expansion valve 534. The resulting refrigerant vapor 536 can then be returned to the refrigerant system. By cooling, a significant amount of condensable hydrocarbons, such as C _{3 and} higher, can be removed. Further, in some embodiments, heat exchanger 530 is placed upstream of expander 516 and a separator is placed between heat exchanger 530 and expander 516 to prevent liquid from flowing into expander 516. .

It should be understood that the process flow diagram of FIG. 5 does not indicate that the expanded refrigeration system 500 should include any of the components shown in FIG. Further, the expansion refrigeration system 500 can include any number of additional components not shown in FIG. 5, depending on the particular implementation details. For example, in some embodiments, the expanded refrigeration system 500 is implemented in a cascade refrigeration system that includes two fluorocarbon refrigeration systems upstream of a nitrogen refrigeration system. In such an embodiment, the refrigerant liquid 532 that flows through the expansion valve 534 and flushes and cools through the cooling device 530 is fed to a fluorocarbon refrigerant from one of the fluorocarbon refrigeration systems, or to a nitrogen refrigeration system. Nitrogen refrigerant derived from.
FIG. 6 is a process flow diagram of an expansion refrigeration system 600 for generating NGL. In various embodiments, NGL extraction can be performed to recover NGL containing any number of different heavy hydrocarbons from a natural gas stream. It may be desirable to extract NGL because it is often more valuable for purposes other than as a gaseous heated fuel.

The dried natural gas feed stream 602 can flow from the dehydration system to the gas / gas heat exchanger 604. Within the gas / gas heat exchanger 604, the dried natural gas feed stream 602 can be cooled via indirect heat exchange with the cold natural gas stream 606. The resulting natural gas stream 608 can flow to the separator 610, thereby removing a portion 612 of NGL from the natural gas stream 608. The removed NGL 612 can flow from the separator 610 to the deethanizer or demethanizer 614.
The natural gas stream 608 can then flow to the expander 616. In various embodiments, the expander 616 is a turbo expander. Expansion of the natural gas stream 608 within the expander 616 can provide energy to drive a compressor 618 that is coupled to the expander 616 via the shaft 620. Further, the temperature of the natural gas stream 608 can be reduced by adiabatic expansion through the Joule-Thomson valve 622.

The resulting cold natural gas stream 606 originating from the expander 616 can flow to the deethanizer or demethanizer 614. Within the deethanizer or demethanizer 614, NGL can be separated from the natural gas stream 606 and can flow out of the deethanizer or demethanizer 614 as an NGL product stream 624. NGL product stream 624 can then be pumped out of expansion refrigeration system 600 via pump 626.
The deethanizer or demethanizer 614 may be connected to the heat exchanger 628. In some embodiments, the heat exchanger 628 is used to heat a portion 630 of the bottom stream derived from the deethanizer or demethanizer 614 via indirect heat exchange with the hot fluid 632. A reboiler 628 that can be produced. The heated bottom stream 630 can then be reinjected into the deethanizer or demethanizer 614.

  Separation of the NGL product stream 624 from the natural gas stream 606 in the deethanizer or demethanizer 614 can produce a cryogenic natural gas stream, which can be used as an overhead stream 634 as a deethanizer or The tower 614 can flow out. Overhead stream 634 can flow to heat exchanger 636, thereby reducing the temperature of overhead stream 634 via indirect heat exchange with a refrigerant 638, such as a fluorocarbon refrigerant or a nitrogen refrigerant. . As the temperature drops, some of the vapor can be condensed. The overhead stream 634 can then be separated in a separation vessel 640 to produce a cold natural gas stream 606 and a liquid bottom stream 642. Bottom stream 642 can be pumped back to deethanizer or demethanizer 614 via pump 644 to form a recycle stream.

  The cold natural gas stream 606 can then flow through the gas / gas heat exchanger 604. The temperature of the cold natural gas stream 506 can be increased in the gas / gas heat exchanger 604 to produce a hot natural gas stream 646. The hot natural gas stream 646 can then flow through the compressor 618, thereby increasing the pressure of the natural gas stream 646. In some embodiments, the hot natural gas stream 646 can also flow through the second compressor 648, thereby increasing the pressure of the natural gas stream 646 to an acceptable sales gas pressure. . The natural gas product stream 650 can then flow out of the expansion refrigeration system 600.

  It should be understood that the process flow diagram of FIG. 6 does not indicate that the expanded refrigeration system 600 should include any of the components shown in FIG. Further, the expansion refrigeration system 600 can include any number of additional components not shown in FIG. 6 depending on the particular implementation details. For example, in some embodiments, the expansion refrigeration system 600 is implemented in a cascade refrigeration system that includes two fluorocarbon refrigeration systems upstream of a nitrogen refrigeration system. In such an embodiment, the refrigerant 638 utilized in the heat exchanger 636 is a fluorocarbon refrigerant derived from one of the fluorocarbon refrigeration systems or a nitrogen refrigerant derived from a nitrogen refrigeration system.

FIG. 7 is a process flow diagram of the LNG generation system 700. As shown in FIG. 7, LNG 702 can be generated from natural gas stream 704 using a number of different refrigeration systems. As shown in FIG. 7, a portion of the natural gas stream 704 can be separated from the natural gas stream 704 before entering the LNG production system 700 and used as the fuel gas stream 706. The remaining natural gas stream 704 can flow to the initial natural gas processing system 708. Within the natural gas processing system 708, the natural gas stream 704 can be purified and cooled. For example, the natural gas stream 704 can be cooled using a first fluorocarbon refrigerant 710, a second fluorocarbon refrigerant 712, and a high pressure nitrogen refrigerant 714. By cooling the natural gas stream 704, LNG 702 can be produced.
Within the LNG production system 700, heavy hydrocarbons 716 can be removed from the natural gas stream 704 and a portion of the heavy hydrocarbons 716 can be used within the heavy hydrocarbon processing system 720. Gasoline 718 can be generated. In addition, any residual natural gas 722 that is separated from heavy hydrocarbons 716 during the production of gasoline 718 can be returned to natural gas stream 704.

The generated LNG 702 may contain a certain amount of nitrogen 724. Accordingly, LNG 702 can flow through NRU 726. NRU 726 separates nitrogen 724 from LNG 702 to produce the final LNG product.
It should be understood that the process flow diagram of FIG. 7 does not indicate that the LNG generation system 700 should include every component shown in FIG. Further, the LNG generation system 700 may include any number of additional components not shown in FIG. 7, or different locations of the apparatus for cooling the fluorocarbon refrigerant in the process, depending on the particular implementation details. it can. For example, LNG 702 can be generated from natural gas stream 704 using any number of alternative refrigeration systems. In addition, any number of different refrigeration systems can be used in combination to produce LNG 702.

System for Generating LNG FIGS. 8A and 8B are process flow diagrams of a cascade cooling system 800. Cascade cooling system 800 can be used to produce LNG and can be implemented in a hydrocarbon processing system. Cascade cooling system 800 can operate at low temperatures, for example, less than about −18 ° C., or less than about −29 ° C., or less than about −40 ° C. Furthermore, in the cascade cooling system 800, two or more refrigerants can be used, and refrigeration can be performed at a plurality of temperatures.
Cascade cooling system 800 can include a first fluorocarbon refrigeration system 802, as shown in FIG. 8A, which utilizes a first fluorocarbon refrigerant, such as R-410A. Can do. Cascade cooling system 800 can also include a second fluorocarbon refrigeration system 804, as shown in FIG. 8B, which utilizes a second fluorocarbon refrigerant, such as R-508B. be able to. Further, the cascade cooling system 800 can include a nitrogen refrigeration system 806, as shown in FIG. 8B.

  The natural gas stream 808 can flow through a cooling device 810, which precools the natural gas stream 808 via indirect heat exchange with a cooling fluid. The natural gas stream 808 can then flow to the pipe joint 812 within the cascade cooling system 800. Pipe joint 812 may be configured to split natural gas stream 808 into three separate natural gas streams. The first natural gas stream can flow to the first fluorocarbon refrigeration system 802 via line 814, and the second natural gas stream and the third natural gas stream are routed via lines 816 and 818, respectively. Can then flow to the system discussed with respect to FIG.

  The natural gas stream can flow to the first fluorocarbon refrigeration system 802 in preparation for cooling the natural gas stream. The natural gas stream can be cooled by passing through a series of heat exchangers 820, 822 and 824 in the first fluorocarbon refrigeration system 802. Heat exchangers 820, 822 and 824 can also be referred to as evaporators, chillers or cooling boxes. The natural gas stream may be cooled via indirect heat exchange with the circulation of the fluorocarbon refrigerant in each of the heat exchangers 820, 822 and 824. The fluorocarbon refrigerant may be a hydrofluorocarbon, such as R-410A or R-404A or any other suitable type of fluorocarbon refrigerant.

Fluorocarbon refrigerant can be continuously circulated through the first fluorocarbon refrigeration system 802, thereby allowing the fluorocarbon refrigerant to continuously enter heat exchangers 820, 822, and 824, respectively. Can be prepared. The fluorocarbon refrigerant can exit the first heat exchanger 820 as a vapor fluorocarbon refrigerant via line 826. The vapor fluorocarbon refrigerant can be combined with additional vapor fluorocarbon refrigerant in the two pipe joints 828 and 829. Next, when the steam flows through the compressor 830 and the pressure of the vapor fluorinated carbon refrigerant increases, an overheated vapor fluorinated carbon refrigerant is generated. The superheated vapor fluorocarbon refrigerant flows through the condenser 832 so that the superheated vapor fluorocarbon refrigerant can be cooled and condensed to produce a liquid fluorocarbon refrigerant.
The liquid fluorocarbon refrigerant can flow through the expansion valve 834, thereby reducing the temperature and pressure of the liquid fluorocarbon refrigerant. This can result in flash evaporation of the liquid fluorocarbon refrigerant and produce a mixture of the liquid fluorocarbon refrigerant and the vapor fluorocarbon refrigerant. Liquid fluorocarbon refrigerant and vapor fluorocarbon refrigerant can flow to first flash tank 836 via line 838. Within the first flash tank 836, the liquid fluorocarbon refrigerant can be separated from the vapor fluorocarbon refrigerant.

  Vapor fluorocarbon refrigerant can flow from the first flash tank 836 to the pipe joint 828 via line 839. The liquid fluorocarbon refrigerant can flow to the pipe joint 840, thereby dividing the liquid fluorocarbon refrigerant into two separate liquid fluorocarbon refrigerant streams. One liquid fluorocarbon refrigerant stream may flow through the first heat exchanger 820, partially or fully flashed, and return to the pipe joint 828 via line 826. The other liquid fluorocarbon refrigerant stream can flow to the second flash tank 842 via line 844. Line 844 can also include an expansion valve 846 that throttles the liquid fluorocarbon refrigerant stream to control the flow of the liquid fluorocarbon refrigerant stream to the second flash tank 842. . Throttle adjustment of the liquid fluorocarbon refrigerant stream within the expansion valve 846 can cause flash evaporation of the liquid fluorocarbon refrigerant stream to produce a mixture of both vapor and liquid fluorocarbon refrigerant.

  The second flash tank 842 can separate the vapor fluorocarbon refrigerant from the liquid fluorocarbon refrigerant. Vaporized fluorocarbon refrigerant can flow to pipe joint 848 via line 850. The pipe joint 848 can match the vapor fluorinated carbon refrigerant with the vapor fluorinated carbon refrigerant recovered from the second heat exchanger 822. The vapor fluorocarbon refrigerant can then flow to another pipe joint 852. The pipe joint 852 can match the vapor fluorocarbon refrigerant with the vapor fluorocarbon refrigerant recovered from the third heat exchanger 824. The combined vapor fluorocarbon refrigerant is compressed in compressor 854 and flows through line 856 to pipe joint 829 where it can be combined with the steam from flash tank 836 and heat exchanger 820.

  The liquid fluorocarbon refrigerant can flow from the second flash tank 842 to the pipe joint 858, whereby the liquid fluorocarbon refrigerant can be split into two separate liquid fluorocarbon refrigerant streams. One liquid fluorocarbon refrigerant stream can flow through the second heat exchanger 822 and return to the pipe joint 848 via line 860. The other liquid fluorocarbon refrigerant stream can flow via line 862 via third heat exchanger 824. Line 862 can also include an expansion valve 864 that flushes the liquid fluorocarbon refrigerant and thus the pressure and temperature at which the liquid fluorocarbon refrigerant stream flows to the third heat exchanger 824. To lower. The liquid fluorocarbon refrigerant stream from the third heat exchanger 824 can be compressed in the compressor 866 and sent to the pipe joint 852 via line 868.

In various embodiments, the fluorocarbon refrigerant of the second fluorocarbon refrigeration system 804 is pre-cooled in the first fluorocarbon refrigeration system 802. For example, the fluorocarbon refrigerant of the second fluorocarbon refrigerant can be pre-cooled by flowing through the first heat exchanger 820. The fluorocarbon refrigerant may be a hydrofluorocarbon, such as R-508B, or any other suitable type of fluorocarbon. The fluorocarbon refrigerant can flow from the second fluorocarbon refrigeration system 804 to the first heat exchanger 820 via line 870.
The natural gas stream is gradually cooled in each of the heat exchangers 820, 822 and 824 and then flows to the second fluorocarbon refrigeration system 804 via line 874 as shown in FIG. 8B. . The second fluorocarbon refrigeration system 804 can include a fourth heat exchanger 876 and a fifth heat exchanger 878, thereby further cooling the natural gas stream using a fluorocarbon refrigerant. be able to.

  The fluorocarbon refrigerant can be continuously circulated through the second refrigeration system 804, thereby preparing the fluorocarbon refrigerant to enter the heat exchangers 876 and 878, respectively. The fluorocarbon refrigerant can exit the fourth heat exchanger 876 as a vapor fluorocarbon refrigerant stream. The vapor fluorinated carbon refrigerant stream can be combined with another vapor fluorinated carbon refrigerant stream in pipe joint 880 and yet another vapor fluorinated from the fifth heat exchanger 878 in another pipe joint 882. Can be combined with a carbon refrigerant stream. The vapor fluorocarbon refrigerant stream can then flow through the compressor 884, thereby increasing the pressure of the vapor fluorocarbon refrigerant stream to produce a superheated fluorocarbon refrigerant stream. Can do. The superheated fluorocarbon refrigerant stream can flow through the pipe joint 886 and another compressor 888, thereby further increasing the pressure of the superheated fluorocarbon refrigerant stream.

The superheated fluorocarbon refrigerant stream can flow through a gas cooler 890. The gas cooler 890 can cool the superheated fluorocarbon refrigerant stream to produce a cooled vapor fluorocarbon refrigerant stream. In some cases, the vapor fluorinated carbon refrigerant stream cannot flow through the gas cooler 890 when the vapor fluorinated carbon refrigerant stream is below ambient temperature. The liquid fluorocarbon refrigerant stream can then flow via line 870 through the first heat exchanger 820 in the first fluorocarbon refrigeration system 802.
Once the fluorocarbon refrigerant stream has passed through the first heat exchanger 820, the fluorocarbon refrigerant stream enters the third flash tank 892 in the second fluorocarbon refrigeration system 804 via line 894. Can do. Line 894 can include an expansion valve 896 that controls the flow of the fluorocarbon refrigerant stream to the third flash tank 892. The expansion valve 896 can reduce the temperature and pressure of the fluorocarbon refrigerant stream to flash vaporize the fluorocarbon refrigerant stream into both the vapor fluorocarbon refrigerant stream and the liquid fluorocarbon refrigerant stream.

  The vapor fluorocarbon refrigerant stream and the liquid fluorocarbon refrigerant stream can be flushed to the third flash tank 892, thereby separating the vapor fluorocarbon refrigerant stream from the liquid fluorocarbon refrigerant stream. . The vapor fluorinated carbon refrigerant stream may flow to the pipe joint 886 via line 898. The liquid fluorocarbon refrigerant stream can flow from the third flash tank 892 to the fourth flash tank 904 via line 906. Line 906 can include an expansion valve 908 that controls the flow of the fluorocarbon refrigerant stream to the fourth flash tank 904. The expansion valve 908 can further reduce the temperature and pressure of the fluorocarbon refrigerant stream to flash vaporize the fluorocarbon refrigerant stream into both the vapor fluorocarbon refrigerant stream and the liquid fluorocarbon refrigerant stream.

  The liquid fluorocarbon refrigerant stream can flow from the fourth flash tank 904 to the pipe joint 910, thereby dividing the liquid fluorocarbon refrigerant stream into two separate liquid fluorocarbon refrigerant streams. . One liquid fluorocarbon refrigerant stream can flow through the fourth heat exchanger 876 and return to the pipe joint 880 via line 912. The other liquid fluorocarbon refrigerant stream can flow via line 914 via a fifth heat exchanger 878. Line 914 can also include an expansion valve 916, which causes the flow of liquid fluorocarbon refrigerant stream to the fifth heat exchanger 878, for example, to flush the fluorocarbon refrigerant stream and increase the temperature. And control by producing a vapor fluorocarbon refrigerant stream and a liquid fluorocarbon refrigerant stream. The resulting vapor fluorocarbon refrigerant stream from the fifth heat exchanger 878 can be compressed in the compressor 918 and then flow to the pipe joint 882 for recirculation.

The natural gas stream can be cooled via indirect heat exchange with the fluorocarbon refrigerant stream in heat exchangers 876 and 878 and then flow to the nitrogen refrigeration system 806 via line 920. In various embodiments, the nitrogen refrigerant stream of the nitrogen refrigeration system 806 is pre-cooled by flowing through each of the heat exchangers 820, 822, 824, and 876. The nitrogen refrigerant stream can flow from line refrigeration system 806 to heat exchangers 820, 822, 824 and 876 via line 921.
Within the nitrogen refrigeration system 806, the natural gas stream can be cooled via indirect heat exchange with the nitrogen refrigerant stream within the sixth heat exchanger 922. The nitrogen refrigerant stream can be continuously circulated through the nitrogen refrigeration system 806, thereby preparing the nitrogen refrigerant stream to enter the sixth heat exchanger 922. The nitrogen refrigerant can flow as two separate nitrogen refrigerant streams via the sixth heat exchanger 922. The nitrogen refrigerant stream originating from the sixth heat exchanger 922 can be combined in the pipe joint 924.

The combined nitrogen refrigerant stream can flow through the seventh heat exchanger 926 by line 928. Within the seventh heat exchanger 926, the nitrogen refrigerant stream can cool the high-pressure nitrogen refrigerant stream flowing in the reverse direction. The nitrogen refrigerant stream from the seventh heat exchanger 926 is compressed in the first compressor 930, cooled in the first chiller 932, compressed in the second compressor 934, and second It can be cooled in the cooling device 936. The resulting high pressure nitrogen refrigerant stream can then flow to pipe joint 938, which can split the high pressure nitrogen refrigerant stream into two separate high pressure nitrogen refrigerant streams.
One high-pressure nitrogen refrigerant stream originating from the pipe joint 938 can flow through the heat exchangers 820, 822, 824 and 876 by line 921. Upon exiting the fourth heat exchanger 876, the nitrogen refrigerant stream expands in the expander 940, generates power, and flows through the sixth heat exchanger 922 to cool the natural gas stream. it can.

The other high pressure nitrogen refrigerant stream can flow from the pipe joint 938 through a third compressor 942, a third chiller 944, and a seventh heat exchanger 926. The high pressure nitrogen refrigerant stream can then expand in expander 946 to generate power and flow through sixth heat exchanger 922 to cool the natural gas stream. The power generated by the expanders 940 and 946 can be used to generate power or to drive all, some (or some) of the compressors 930, 934 or 942.
FIG. 9 is a process flow diagram of a system 900 that includes an NRU 902. System 900 can be located downstream of cascade cooling system 800 and can be implemented in the same hydrocarbon treatment system as cascade cooling system 800.

Once the natural gas stream has been cooled in the nitrogen refrigeration system 806, the natural gas stream can take the form of LNG. The LNG stream can flow to system 900 via line 948. Specifically, the LNG stream can flow to the pipe joint 950, whereby the LNG stream from line 948 can be combined with the natural gas stream from line 816. Initial cooling of the natural gas stream from line 816 may be performed in the eighth heat exchanger 952 before the natural gas stream flows to the pipe joint 950.
When the LNG stream originating from the pipe joint 950 flows to the NRU 902, excess nitrogen can be removed from the LNG stream. Specifically, the LNG stream can flow to the reboiler 954, thereby reducing the temperature of the LNG stream. The cooled LNG stream can expand within the hydraulic expansion turbine 956 and then flow through the expansion valve 958, thereby reducing the temperature and pressure of the LNG stream.

  The LNG stream can flow within the NRU 902 to a cryogenic preparative column 960 such as an NRU tower. Further, heat can be transferred from reboiler 954 to cryogenic preparative column 960 via line 962. The cryogenic preparative column 960 can separate nitrogen from the LNG stream via a cryogenic distillation process. The overhead stream can flow out of cryogenic preparative column 960 via line 964. The overhead stream can contain primarily methane, nitrogen, and other low boiling or noncondensable gases such as helium, separated from the LNG stream.

  In some embodiments, the overhead stream flows to an overhead condenser (not shown), thereby separating any liquid in the overhead stream and returning it to the cryogenic preparative column 960 as reflux. it can. This can produce one vapor stream, a fuel stream containing mainly methane, and another vapor stream containing mainly low boiling gas. The fuel stream can flow through the eighth heat exchanger 952 by line 964. Within the eighth heat exchanger 952, as the temperature of the steam fuel stream increases via indirect heat exchange with the natural gas stream, a steam fuel stream may be generated. The steam fuel stream can be combined with other steam fuel streams in the pipe joint 966. The combined vapor fuel stream can then be compressed and cooled in a series of compressors 968, 970 and 972, and chillers 974, 976, 978. The resulting steam fuel stream can be combined in a pipe joint 980 with a natural gas stream from line 818 that can be a steam fuel stream from natural gas stream 808. The vapor fuel stream can then flow out of system 900 as fuel 982 via line 984.

  The bottom stream produced in the cryogenic preparative column 960 contains mainly LNG containing trace amounts of nitrogen. The LNG stream can flow to the LNG tank 986 via line 988. Line 988 can include a valve 990, which is used to control the flow of the LNG stream to the LNG tank 986. The LNG tank 986 can store the LNG stream for an arbitrary period. Boil-off gas generated in the LNG tank 986 can flow to the pipe joint 966 via line 992. At any point in time, the final LNG stream 994 can be transported to the LNG tanker 996 using a pump 998 for transport to the market. Additional boil-off gas 999 generated while loading the final LNG stream 944 on the LNG tanker 996 can be recovered in the cascade cooling system 800.

  It should be understood that the process flow diagrams of FIGS. 8A, 8B and 9 do not indicate that the cascade cooling system 800 or system 900 should include any of the components shown in FIG. 8A, 8B or 9. . Further, cascade cooling system 800 or system 900 may include any number of additional components not shown in FIGS. 8A, 8B, or 9, respectively, depending on the specific implementation details. In various embodiments, heat exchangers 820, 822, 824, 876, 878 and 922 include high convection rate type tubes. By using such high convection rate type tubes, the size of the device and the list of refrigerants used to cool in the heat exchangers 820, 822, 824, 876, 878 and 922 are reduced. be able to. Further, any of the heat exchangers 820, 822, 824, 876, 878, 922 or 926 can be included in a spiral type unit or a brazed aluminum type unit.

In various embodiments, the compressors 830, 854, 866, 888, 884, 918, 930, 934, 942, 968, 972 and 976 are centrifugal type compressors. In order to reduce the loss of refrigerant to the atmosphere, each compressor 830, 854, 866, 888, 884, 918, 930, 934, 942, 968, 972, and 976 is reclaimer or seal leak. leak) gas recovery system may also be included.
10A and 10B are process flow diagrams of another cascaded cooling system 1000. Cascade cooling system 1000 may be a modified version of cascade cooling system 800 of FIGS. 8A and 8B. The numbered items are the same as those described with respect to FIGS. 8A and 8B. Cascade cooling system 1000 can be implemented in a hydrocarbon processing system.

Cascade cooling system 1000 can include a first fluorocarbon refrigeration system 1002, as shown in FIG. 10A, which utilizes a first fluorocarbon refrigerant, such as R-410A. Can do. Cascade cooling system 1000 can also include a second fluorocarbon refrigeration system 1004, as shown in FIG. 10B, which utilizes a second fluorocarbon refrigerant, such as R-508B. be able to. Further, the cascade cooling system 1000 can include a nitrogen refrigeration system 1006, as shown in FIG. 10B.
The first fluorocarbon refrigeration system 1002 of FIG. 10A may be similar to the first fluorocarbon refrigeration system 802 of FIG. 8A. However, the first fluorocarbon refrigeration system 1002 of FIG. 10A is replaced by the second and third heat exchangers 1008 and 1008 instead of the heat exchangers 822, 824 in the first fluorocarbon refrigeration system 802 of FIG. A heat exchanger 1010 can be included.

Within the first fluorocarbon refrigeration system 1002, the fluorocarbon refrigerant of the second fluorocarbon refrigeration system 1004 is pre-cooled and condensed by flowing through the heat exchangers 820, 1008 and 1010, respectively. Subcooled. The fluorocarbon refrigerant may be a hydrofluorocarbon, such as R-508B, or any other suitable type of fluorocarbon. The fluorocarbon refrigerant can flow from the second fluorocarbon refrigeration system 1004 to the heat exchangers 820, 1008 and 1010 in the first fluorocarbon refrigeration system 1002 via line 870. Accordingly, since the fluorocarbon refrigerant flows through all three heat exchangers 802, 1008 and 1010, the first fluorocarbon refrigeration system 1002 of FIG. 10A is the first fluorocarbon refrigeration of FIG. 8A. The pre-cooling degree of the second fluorocarbon refrigerant can be increased as compared with the system 802, and the degree of compression can be suppressed.
The natural gas stream is cooled for removal in each of the heat exchangers 820, 1008 and 1010. The cooled natural gas stream then flows to the second fluorocarbon refrigeration system 1004 via line 874, as shown in FIG. 10B. The second fluorocarbon refrigeration system 1004 can include a fourth heat exchanger 876 and a fifth heat exchanger 1012, thereby further cooling the natural gas stream using a fluorocarbon refrigerant. be able to.

  The fluorocarbon refrigerant can be continuously circulated through the second refrigeration system 1004 so that the fluorocarbon refrigerant enters each of the heat exchangers 876 and 1012. The fluorocarbon refrigerant can exit the fourth heat exchanger 876 as a vapor fluorocarbon refrigerant stream. The vapor fluorocarbon refrigerant stream can be combined with another vapor fluorocarbon refrigerant stream within pipe joint 880 and another vapor fluorocarbon refrigerant stream originating from the fifth heat exchanger 1012 within pipe joint 882. Can be combined. The vapor fluorocarbon refrigerant stream can then flow through the compressor 884, thereby increasing the pressure of the vapor fluorocarbon refrigerant stream. The steam can then flow through the first heat exchanger 820 in the first fluorocarbon refrigeration system 1002 via line 870.

  Once the fluorocarbon refrigerant stream has passed through heat exchangers 820, 1008 and 1010, it can enter the third flash tank 1013 in the second fluorocarbon refrigeration system 1004 via line 1014. Line 1014 can include an expansion valve 908 that controls the flow of the fluorocarbon refrigerant stream to the third flash tank 1013. The expansion valve 908 can reduce the temperature and pressure of the fluorocarbon refrigerant stream to flash evaporate the fluorocarbon refrigerant stream into both the vapor fluorocarbon refrigerant stream and the liquid fluorocarbon refrigerant stream.

  The vapor fluorocarbon refrigerant stream and the liquid fluorocarbon refrigerant stream can be flushed to a third flash tank 1013, thereby separating the vapor fluorocarbon refrigerant stream from the liquid fluorocarbon refrigerant stream. . The vapor fluorocarbon refrigerant stream can flow to pipe joint 880 via line 1016. The liquid fluorocarbon refrigerant stream can flow from the third flash tank 1013 to the pipe joint 910, thereby dividing the liquid fluorocarbon refrigerant stream into two separate liquid fluorocarbon refrigerant streams. . One liquid fluorocarbon refrigerant stream can flow through the fourth heat exchanger 876 and return to the pipe joint 880 via line 912. The other liquid fluorocarbon refrigerant stream can flow via line 914 through fifth heat exchanger 1012. Line 914 may also include an expansion valve 916 that causes the flow of liquid fluorocarbon refrigerant stream to the fifth heat exchanger 1012, for example, to flush the fluorocarbon refrigerant stream and increase the temperature. And control by producing a vapor fluorocarbon refrigerant stream and a liquid fluorocarbon refrigerant stream. The resulting vapor fluorocarbon refrigerant stream from the fifth heat exchanger 1012 can be compressed in the compressor 918 and then flow to the pipe joint 882 for recirculation.

The natural gas stream may be cooled in heat exchangers 876 and 878 via indirect heat exchange with the fluorocarbon refrigerant stream and then flow to nitrogen refrigeration system 1006 via line 920. In various embodiments, the nitrogen refrigerant stream of the nitrogen refrigeration system 1006 is pre-cooled by flowing through each of the heat exchangers 820, 1008, 1010, 876 and 1012. A nitrogen refrigerant stream can flow from line refrigeration system 1006 to heat exchangers 820, 1008, 1010, 876 and 1012 via line 921.
Within the nitrogen refrigeration system 1006, the natural gas stream may be cooled in the sixth heat exchanger 1018 via indirect heat exchange with the nitrogen refrigerant stream. The nitrogen refrigerant stream can be continuously circulated through the nitrogen refrigeration system 1006, thereby preparing the nitrogen refrigerant stream to enter the sixth heat exchanger 1018.

  The nitrogen refrigerant stream originating from the sixth heat exchanger 1018 can be combined with another nitrogen refrigerant stream within the pipe joint 1020. The combined nitrogen refrigerant stream can flow through the seventh heat exchanger 926 by line 928. Within the seventh heat exchanger 926, the nitrogen refrigerant stream can cool the high-pressure nitrogen refrigerant stream flowing in the reverse direction. The nitrogen refrigerant stream from the seventh heat exchanger 926 is compressed in the first compressor 930, cooled in the first chiller 932, compressed in the second compressor 934, and second May be cooled in the first chiller 936, compressed in the third compressor 1022, and cooled in the third chiller 1024. The resulting high pressure nitrogen refrigerant stream can then flow to the pipe joint 1026, which can split the high pressure nitrogen refrigerant stream into two separate high pressure nitrogen refrigerant streams.

One high-pressure nitrogen refrigerant stream originating from the pipe joint 1026 can flow through the heat exchangers 820, 1008, 1010, 876 and 1012 by line 921. Upon exiting the fifth heat exchanger 1012, the nitrogen refrigerant stream expands in the expander 1028, creating power, flows to the pipe joint 1020, and merges with the nitrogen refrigerant stream exiting the sixth heat exchanger 1018. be able to.
The other high pressure nitrogen refrigerant stream can flow from the pipe joint 1026 via the seventh heat exchanger 926. The high pressure nitrogen refrigerant stream can then expand in expander 1030 to generate power and flow through sixth heat exchanger 1018 to cool the natural gas stream. The power generated in the expanders 1028 and 1030 can be used to generate electricity or drive a portion of the compressor 930, 934 or 1022.

Once the natural gas stream is cooled in the nitrogen refrigeration system 1006, the natural gas stream can take the form of LNG. The LNG stream can flow via line 948 to the system 900 of FIG. Within system 900, nitrogen can be removed from LNG within NRU 902, and a final LNG stream 994 can be obtained as discussed with respect to FIG.
FIG. 10C is a process flow diagram of an alternative embodiment of a cascade cooling system 1000 that includes a simplified nitrogen refrigeration system 1032. As shown in FIG. 10C, pipe joints 1020 and 1026, seventh heat exchanger 926, expander 1030, and cooling devices 932 and 936 are not included in nitrogen refrigeration system 1032. Further, the first compressor 930 and the second compressor 934 are combined into a single unit, ie, the compressor 1134. In such an embodiment, the entire nitrogen refrigerant stream flows through heat exchangers 820, 1008, 1010, 876 and 1012 by line 921. Accordingly, such an embodiment is a simplified design of the cascade cooling system 1000. The power generated by the expander 1028 can be used to generate power or drive a portion of the compressor 1022 or 1134.

It should be understood that the process flow diagrams of FIGS. 10A, 10B, and 10C do not indicate that the cascade cooling system 1000 should include any components shown in FIGS. 10A, 10B, and 10C. Further, the cascade cooling system 1000 can include any number of additional components not shown in FIGS. 10A, 10B, and 10C, depending on the particular implementation details.
FIGS. 11A and 11B are process flow diagrams of another cascaded cooling system 1100. Cascade cooling system 1100 may be a modified version of cascade cooling systems 800 and 1000 of FIGS. 8A, 8B, 10A, 10B, and 10C, respectively. The numbered items are the same as those described with respect to FIGS. 8A, 8B, 10A, 10B and 10C. Cascade cooling system 1100 can be implemented in a hydrocarbon processing system.

Cascade cooling system 1100 can include a first fluorocarbon refrigeration system 1102 as shown in FIG. 11A, which utilizes a first fluorocarbon refrigerant, eg, R-410A. Can do. Cascade cooling system 1100 can include a second fluorocarbon refrigeration system 1104, as shown in FIG. 11B, which utilizes a second fluorocarbon refrigerant, such as R-508B. Can do.
FIG. 11C is a process flow diagram of an automatic refrigeration system 1105 implemented within the same hydrocarbon treatment system as the cascade cooling system 1100 of FIGS. 11A and 11B. The numbered items are the same as those described with respect to FIGS. 8A, 8B, 9, 10A, 10B, 10C, 11A and 11B. An automatic refrigeration system 1105 can be used to generate LNG from a natural gas stream. Further, the automatic refrigeration system 1105 can include an NRU 1106 for removing nitrogen from the natural gas stream.

  The natural gas stream 808 can flow through a cooling device 810, which precools the natural gas stream 808 via indirect heat exchange with a cooling fluid. The natural gas stream 808 can then flow to the pipe joint 812 within the cascade cooling system 1100. Pipe joint 812 may be configured to split natural gas stream 808 into three separate natural gas streams. The first natural gas stream can flow to the pipe joint 1107 via line 814, and the second and third natural gas streams are directed to the automatic refrigeration system 1105 via lines 816 and 818, respectively. Can flow.

Within the pipe joint 1107, the natural gas stream can be combined with the methane recycle stream returning from the automatic refrigeration system 1105 via line 1108. The combined natural gas stream can then flow to the first fluorocarbon refrigeration system 1102 in preparation for cooling the natural gas stream. The natural gas stream may be cooled by passing through a series of heat exchangers 1110, 822, and 824 within the first fluorocarbon refrigeration system 1102. The natural gas stream may be cooled via indirect heat exchange with the circulating fluorocarbon refrigerant in each of the heat exchangers 1110, 822 and 824, as discussed with respect to FIG. 8A.
The cooled natural gas stream then flows to the second fluorocarbon refrigeration system 1104 via line 874 as shown in FIG. 11B. The second fluorocarbon refrigeration system 1104 can include a fourth heat exchanger 1112 and a fifth heat exchanger 1114, thereby further cooling the natural gas stream using a fluorocarbon refrigerant. be able to.

The fluorocarbon refrigerant can be continuously circulated through the second refrigeration system 1104, whereby the fluorocarbon refrigerant is prepared to enter the heat exchangers 1112 and 1114, respectively. The fluorocarbon refrigerant can exit the fourth heat exchanger 1112 as a vapor fluorocarbon refrigerant stream. The vapor fluorocarbon refrigerant stream can be combined with another vapor fluorocarbon refrigerant stream within pipe joint 880 and another vapor fluorocarbon refrigerant stream originating from fifth heat exchanger 1114 within pipe joint 882. Can be combined. The vapor fluorocarbon refrigerant stream can then flow through the compressor 884, thereby increasing the pressure of the vapor fluorocarbon refrigerant stream. The steam can then flow via line 870 through the first heat exchanger 1110 in the first fluorocarbon refrigeration system 1102.
As the fluorocarbon refrigerant stream passes through heat exchangers 1110, 822 and 824, the fluorocarbon refrigerant stream enters a third flash tank 1013 in the second fluorocarbon refrigeration system 1104 via line 1014. be able to. Line 1014 can include an expansion valve 908 that controls the flow of the fluorocarbon refrigerant stream to the third flash tank 1013. The expansion valve 908 can reduce the temperature and pressure of the fluorocarbon refrigerant stream to flash evaporate the fluorocarbon refrigerant stream into both the vapor fluorocarbon refrigerant stream and the liquid fluorocarbon refrigerant stream.

  The vapor fluorocarbon refrigerant stream and the liquid fluorocarbon refrigerant stream can be flushed to a third flash tank 1013, thereby separating the vapor fluorocarbon refrigerant stream from the liquid fluorocarbon refrigerant stream. . The vapor fluorocarbon refrigerant stream can flow to pipe joint 880 via line 1016. The liquid fluorocarbon refrigerant stream can flow from the third flash tank 1013 to the pipe joint 910, thereby dividing the liquid fluorocarbon refrigerant stream into two separate liquid fluorocarbon refrigerant streams. . One liquid fluorocarbon refrigerant stream can flow through the fourth heat exchanger 1112 and return to the pipe joint 880 via line 912. The other liquid fluorocarbon refrigerant stream can flow via line 914 via fifth heat exchanger 1114. Line 914 can also include an expansion valve 916, which causes the flow of liquid fluorocarbon refrigerant stream to the fifth heat exchanger 1114, for example, to flush the fluorocarbon refrigerant stream and increase the temperature. And control by producing a vapor fluorocarbon refrigerant stream and a liquid fluorocarbon refrigerant stream. The resulting vapor fluorocarbon refrigerant stream from the fifth heat exchanger 1114 can be compressed in the compressor 918 and then flow to the pipe joint 882 for recirculation.

  After the natural gas stream is cooled via indirect heat exchange with the fluorocarbon refrigerant stream in heat exchangers 1112 and 1114, the natural gas stream flows to the automatic refrigeration system 1105 via line 1116. Can do. More specifically, the natural gas stream can flow to a sixth heat exchanger 1118 in the automatic refrigeration system 1105. Within the sixth heat exchanger 1118, the natural gas stream may be cooled via indirect heat exchange with a lower temperature natural gas stream flowing in the opposite direction.

  The natural gas stream from the sixth heat exchanger 1118 can flow to the pipe joint 1120, thereby splitting the natural gas stream into two separate natural gas streams. One natural gas stream can flow through the expansion valve 1122, thereby reducing the temperature and pressure of the natural gas stream. The cold natural gas stream can then flow to the sixth heat exchanger 1118 via line 1124 and can be used to cool the natural gas stream in the sixth heat exchanger 1118. The natural gas stream from the sixth heat exchanger 1118 can flow to the pipe joint 1126 where it can be combined with another natural gas stream. The combined natural gas stream can be compressed in compressor 1128 and then flow to pipe joint 1107 in first fluorocarbon refrigeration system 1102.

The other natural gas stream from pipe joint 1120 can flow to additional pipe joint 1130 where it can be combined with another natural gas stream. As the combined natural gas stream flows to the NRU 1106, excess nitrogen can be removed from the natural gas stream. Specifically, the natural gas stream can flow to a reboiler 954, thereby reducing the temperature of the natural gas stream. The cooled natural gas stream can be expanded in a hydraulic expansion turbine 986 and then flow through an expansion valve 988, thereby reducing the temperature and pressure of the natural gas stream.
The natural gas stream can flow to a cryogenic preparative column 960 in the NRU 1106. Further, heat can be transferred from reboiler 954 to cryogenic preparative column 960 via line 962. The cryogenic preparative column 960 can separate nitrogen from the natural gas stream via a cryogenic distillation process. The overhead stream can flow out of cryogenic preparative column 960 via line 964. The overhead stream can include primarily methane, nitrogen, and other low boiling or noncondensable gases such as helium, separated from the natural gas stream.

  In some embodiments, the overhead stream flows to an overhead condenser 1132, thereby separating any liquid in the overhead stream and passing it through line 1134 as a reflux to a cryogenic preparative column 960. Can be returned. This can produce one vapor stream, a fuel stream containing mainly methane, and another vapor stream containing mainly low boiling gas. The fuel stream can flow through the seventh heat exchanger 1136 by line 964. Within the seventh heat exchanger 1136, as the temperature of the steam fuel stream increases via indirect heat exchange with the natural gas stream originating from line 816, a steam fuel stream may be generated. The vapor fuel stream may be compressed and chilled in a series of compressors 1138 and 1140 and chilling devices 1142 and 1144. The resulting steam fuel stream can be combined in a pipe joint 980 with a natural gas stream from line 818 that can be a steam fuel stream from natural gas stream 808. The vapor fuel stream can then flow out of system 1105 as fuel 982 via line 984.

The bottom stream produced in the cryogenic preparative column 960 contains mainly LNG containing trace amounts of nitrogen. The bottom stream can flow through overhead condenser 1132 by line 1146. Line 1146 may also include an expansion valve 1148 that controls the flow of the bottom stream to overhead condenser 1132. The bottom stream can be used as a refrigerant for the overhead condenser 1132.
The resulting mixed phase stream from the overhead condenser 1132 can flow to the first flash tank 1150 via line 1152. The first flash tank 1150 can separate the mixed phase stream into a steam stream containing primarily natural gas and an LNG stream. The steam stream can flow to the pipe joint 1154. The pipe joint 1154 can combine the steam stream with another steam stream recovered from the second flash tank 1156. The combined vapor stream can flow to compressor 1158 via line 1160. A natural gas stream originating from the compressor 1158 can flow to the pipe joint 1126.

The LNG stream from the first flash tank 1150 can flow to the second flash tank 1156 via line 1162. Line 1162 can include an expansion valve 1164 that controls the flow of the LNG stream to the second flush tank 1156 to flush a portion of the liquid originating from the LNG stream, A mixed phase system flows into the flash tank 1156.
The second flash tank 1156 can separate the mixed phase stream into a vapor stream containing LNG and natural gas. The steam stream can flow to the pipe joint 1166 via line 1168. The pipe joint 1166 can combine the steam stream with another steam stream recovered from the third flash tank 1170. The combined steam stream can be compressed in compressor 1172 and flow to pipe joint 1154.

The LNG stream can then flow to the third flash tank 1170 via line 1174. Line 1174 can include an expansion valve 1176 that controls the flow of the LNG stream to the third flush tank 1170 and flushes a portion of the liquid originating from the LNG. The third flash tank 1170 can further reduce the temperature and pressure of the LNG stream so that the LNG stream approaches the equilibrium temperature and pressure. The generated steam stream can flow to the pipe joint 1178 so that the steam stream can be combined with the boil-off gas recovered from the LNG tank 1180. The combined steam stream can be compressed in compressor 1182 and flow to pipe joint 1166.
The LNG stream can flow to the LNG tank 1180 via line 1184. The LNG tank 1180 can store the LNG stream for an arbitrary period. The boil-off gas generated in the LNG tank 1180 can flow to the pipe joint 1178 via the line 1186. At any point in time, the final LNG stream 994 can be transported to the LNG tanker 996 using a pump 998 for transport to the market. Additional boil-off gas 999 generated during loading of the final LNG stream 944 on the LNG tanker 996 can be recovered in the cascade cooling system 1100.

It is understood that the process flow diagrams of FIGS. 11A, 11B and 912 do not indicate that the cascade cooling system 1100 or automatic refrigeration system 1105 should include any of the components shown in FIG. 11A, 11B or 11C. I want to be. Further, the cascade cooling system 1100 or the automatic refrigeration system 1105 can include any number of additional components not shown in FIGS. 11A, 11B, or 11C, respectively, depending on the particular implementation details.
The pressures of the refrigerant streams in the cascade cooling systems 800, 1000, and 1100 of FIGS. 8A and 8B; 10A, 10B, and 10C; 11A and 11B can vary significantly, respectively. In some embodiments, the minimum refrigerant pressure is slightly above local atmospheric pressure, but may be a vacuum. In other embodiments, the minimum refrigerant pressure is about 7-9 psia. As a result, the refrigerant temperature is reduced and the amount mounted on the fluorocarbon refrigeration system is increased, but the amount mounted on the nitrogen refrigeration system or the methane automatic refrigeration system is reduced. In some embodiments, the use of low atmospheric pressure allows the refrigerant power to be transferred between different fluorocarbon refrigeration systems to balance the load and provide a more maneuverable driver. Can be used. For example, in some cases, the refrigerant transfer mechanism may be the same for all fluorocarbon refrigeration systems and nitrogen refrigeration systems.

Method for Forming LNG FIG. 12 is a process flow diagram of a method 1200 for forming LNG from a natural gas stream. The method 1200 can be implemented in any suitable type of hydrocarbon processing system. The method 1200 begins at block 1202, where the natural gas stream is cooled in a first fluorocarbon refrigeration system. The first fluorocarbon refrigeration system may be a mechanical refrigeration system, a valve expansion system, a turbine expansion system, or the like. The first fluorocarbon refrigeration system uses a first fluorocarbon refrigerant to cool the natural gas stream. The first fluorocarbon refrigerant may be, for example, a hydrofluorocarbon refrigerant, such as R-410A, or any other suitable type of fluorocarbon refrigerant.

  In various embodiments, the first fluorocarbon refrigerant is compressed to provide a compressed first fluorocarbon refrigerant, and the compressed first fluorocarbon refrigerant is in communication with the cooling fluid. Cooled by indirect heat exchange. The compressed first fluorocarbon refrigerant can be expanded to cool the compressed first fluorocarbon refrigerant, thereby producing an expanded and cooled first fluorocarbon refrigerant. . The expanded and cooled first fluorocarbon refrigerant can pass through a heat exchange zone, which can be any suitable type of heat exchanger, such as a cooling device or an evaporator. Furthermore, the natural gas stream can be compressed and cooled by indirect heat exchange with an external cooling fluid. The natural gas stream can then be cooled in the heat exchange zone using the first expanded and cooled fluorocarbon refrigerant.

The first fluorocarbon refrigeration system can also include any number of additional refrigeration stages for cooling the natural gas stream. For example, a first fluorocarbon refrigeration system is a three-stage refrigeration system that includes three heat exchange zones for cooling a natural gas stream via indirect heat exchange with a first fluorocarbon refrigerant. There may be.
At block 1204, the natural gas stream is cooled with a second fluorocarbon refrigeration system. The second fluorocarbon refrigeration system may be a mechanical refrigeration system, a valve expansion system, a turbine expansion system, or the like. In the second fluorocarbon refrigeration system, a second fluorocarbon refrigerant is used to cool the natural gas stream. The second fluorocarbon refrigerant may be, for example, a hydrofluorocarbon refrigerant, such as R-508B, or any other suitable type of fluorocarbon refrigerant.

  In various embodiments, the second fluorocarbon refrigerant is compressed to provide a compressed second fluorocarbon refrigerant, and the compressed second fluorocarbon refrigerant is in communication with the cooling fluid. Cooled by indirect heat exchange. The compressed second fluorocarbon refrigerant can be expanded to cool the compressed second fluorocarbon refrigerant, thereby generating an expanded and cooled second fluorocarbon refrigerant. . The expanded and cooled second fluorocarbon refrigerant can pass through a heat exchange zone, which can be any suitable type of heat exchanger, such as a cooling device or an evaporator. Furthermore, the natural gas stream can be compressed and cooled by indirect heat exchange with an external cooling fluid. The natural gas stream can then be cooled in the heat exchange zone using a second expanded and cooled fluorocarbon refrigerant.

The second fluorocarbon refrigeration system can also include any number of additional refrigeration stages for cooling the natural gas stream. For example, the second fluorocarbon refrigeration system is a two-stage refrigeration system that includes two heat exchange zones for cooling the natural gas stream via indirect heat exchange with a second fluorocarbon refrigerant. There may be. Furthermore, the second fluorocarbon refrigerant can be pre-cooled in the first fluorocarbon refrigeration system. Precooling can be achieved, for example, by flowing a second fluorocarbon refrigerant through a heat exchange region in the first fluorocarbon refrigeration system.
At block 1206, the natural gas stream is liquefied to form LNG in a nitrogen refrigeration system. Nitrogen refrigerant can be used to liquefy the natural gas stream in a nitrogen refrigeration system. The nitrogen refrigerant can be maintained in a gas phase state in the nitrogen refrigeration system. In various embodiments, the nitrogen is compressed, cooled with a series of compressors and chillers, and expanded in a hydraulic expansion turbine to produce power, reduce the temperature of the nitrogen refrigerant, and flow through the heat exchanger. . Within the heat exchanger, the nitrogen refrigerant can liquefy the natural gas stream through indirect heat exchange with the natural gas stream to produce LNG.

At block 1208, nitrogen is removed from the LNG with NRU. The NRU can include a cryogenic preparative column, such as an NRU column. Nitrogen separated from LNG can flow out of the cryogenic preparative column as an overhead stream, and LNG can flow out of the cryogenic preparative column as a bottom stream. Furthermore, the reflux condenser can be cooled at the top of the nitrogen removal unit using a liquid supply from the bottom of the nitrogen removal unit.
The process flow diagram of FIG. 12 does not indicate that the steps of method 1200 should be performed in any particular order or that all of the steps should be included in all cases. I want you to understand. Moreover, any number of additional steps may be included in method 1200, depending on the particular implementation details.

FIG. 13 is a process flow diagram of another method 1300 for forming LNG from a natural gas stream. The numbered items are the same as those described with respect to FIG. The method 1300 may be performed in any suitable type of hydrocarbon processing system. The method 1300 includes cooling the natural gas stream at block 1202 of the first fluorocarbon refrigeration system and cooling the natural gas stream at block 1204 of the second fluorocarbon refrigeration system.
Further, at block 1302, the natural gas stream is cooled to form LNG in a methane auto refrigeration system. The methane automatic refrigeration system can include multiple expansion valves and flash tanks for cooling natural gas. In some embodiments, the methane auto refrigeration system is the auto refrigeration system 1105 discussed with respect to FIG. 11C. Further, in some embodiments, the nitrogen removal unit is located upstream of the methane automatic refrigeration system.

It is understood that the process flow diagram of FIG. 13 does not indicate that the steps of method 1300 should be performed in any particular order or that all of the steps should be included in every case. I want. Moreover, any number of additional steps may be included in method 1300, depending on the particular implementation details.
Embodiments of the present invention can include any combination of the methods and systems shown in the following numbered paragraphs. Since any number of variations may be envisaged from the description herein, the following should not be construed as a complete list of all possible embodiments.

1. A first fluorocarbon refrigeration system configured to cool natural gas using a first fluorocarbon refrigerant;
A second fluorocarbon refrigeration system configured to further cool natural gas using a second fluorocarbon refrigerant;
Liquefied natural gas, comprising a nitrogen refrigeration system configured to cool natural gas using nitrogen refrigerant to produce LNG, and a nitrogen removal unit configured to remove nitrogen from LNG LNG) hydrocarbon treatment system.
2. The hydrocarbon treatment system of paragraph 1, wherein the first fluorocarbon refrigeration system is configured to cool the second fluorocarbon refrigerant of the second fluorocarbon refrigeration system.
3. The hydrocarbon treatment of any of paragraphs 1 or 2, wherein the first fluorocarbon refrigeration system or the second fluorocarbon refrigeration system, or both, is configured to cool the nitrogen refrigerant of the nitrogen refrigeration system. system.
4). The hydrocarbon treatment system of any of paragraphs 1-3, wherein the first fluorinated carbon refrigeration system or the second fluorinated carbon refrigeration system, or both, comprise a plurality of cooling cycles.
5. The carbonization of any of paragraphs 1-4, wherein the nitrogen refrigeration system includes a number of heat exchangers configured to cool the natural gas via indirect heat exchange between the natural gas and the nitrogen refrigerant. Hydrogen treatment system.

6). The first fluorocarbon refrigeration system
A compressor configured to compress the first fluorocarbon refrigerant to provide a compressed first fluorocarbon refrigerant;
A cooling device configured to cool the compressed first fluorocarbon refrigerant by indirect heat exchange with a cooling fluid;
Configured to expand the compressed first fluorocarbon refrigerant to cool the compressed first fluorocarbon refrigerant, thereby producing a cooled first fluorocarbon refrigerant. Any of paragraphs 1-5, including a valve and a heat exchanger configured to cool natural gas via indirect heat exchange with a cooled first fluorocarbon refrigerant Hydrocarbon treatment system.

7). The second fluorocarbon refrigeration system
A compressor configured to compress the second fluorocarbon refrigerant to provide a compressed second fluorocarbon refrigerant;
A cooling device configured to cool the compressed second fluorocarbon refrigerant by indirect heat exchange with a cooling fluid;
Configured to expand the compressed second fluorocarbon refrigerant and to cool the compressed second fluorocarbon refrigerant, thereby producing a cooled second fluorocarbon refrigerant. Any of paragraphs 1-6, including a heat exchanger configured to cool natural gas via indirect heat exchange with a cooled second fluorocarbon refrigerant Hydrocarbon treatment system.

8). The hydrocarbon treatment system of any of paragraphs 1-7, wherein the first fluorocarbon refrigerant comprises R-410A.
9. The hydrocarbon treatment system of any of paragraphs 1-8, wherein the second fluorocarbon refrigerant comprises R-508B.
10. The hydrocarbon treatment system of any of paragraphs 1-9, wherein the first or second fluorocarbon refrigerant, or both, comprises a non-toxic non-flammable refrigerant.
11. The hydrocarbon treatment of any of paragraphs 1 through 10, wherein the first fluorocarbon refrigeration system or the second fluorocarbon refrigeration system, or both, includes two or more chillers and two or more compressors. system.
12 The hydrocarbon treatment system of any of paragraphs 1-11, wherein the first fluorocarbon refrigeration system and the second fluorocarbon refrigeration system are implemented in series.

13. The hydrocarbon treatment system of any of paragraphs 1-12, wherein the nitrogen refrigerant is in a gas phase.
14 14. The hydrocarbon treatment system of any of paragraphs 1-13, wherein the nitrogen refrigeration system includes two or more chillers, two or more expanders, and two or more compressors.
15. The hydrocarbon treatment system of any of paragraphs 1 through 14, wherein the hydrocarbon treatment system is configured to cool natural gas to control a hydrocarbon dew point.
16. The hydrocarbon treatment system of any of paragraphs 1-15, wherein the hydrocarbon treatment system is configured to cool natural gas to extract a natural gas liquid.
17. 17. The hydrocarbon treatment system of any of paragraphs 1-16, configured to separate methane and lighter gases from carbon dioxide and heavier gases.
18. 18. The hydrocarbon treatment system of any of paragraphs 1-17, configured to prepare hydrocarbons for producing and storing liquefied petroleum gas.
19. The hydrocarbon treatment system of any of paragraphs 1 through 18, configured to condense the reflux stream.

20. Cooling natural gas with a first fluorocarbon refrigeration system;
Cooling natural gas in a second fluorocarbon refrigeration system;
Liquefying natural gas in a nitrogen refrigeration system to form LNG;
Removing nitrogen from the LNG with a nitrogen removal unit. A method for forming liquefied natural gas (LNG).
21. The method of paragraph 20, comprising cooling the second fluorocarbon refrigerant of the second fluorocarbon refrigeration system within the first fluorocarbon refrigeration system.
22. The method of any of paragraphs 20 or 21, comprising cooling the nitrogen refrigerant of the nitrogen refrigeration system within the first fluorinated carbon refrigeration system or the second fluorinated carbon refrigeration system, or both.

23. Cooling the natural gas in the first fluorocarbon refrigeration system,
Compressing the first fluorocarbon refrigerant to provide a compressed first fluorocarbon refrigerant;
The compressed first fluorocarbon refrigerant may be cooled by indirect heat exchange with a cooling fluid;
Expanding the compressed first fluorocarbon refrigerant to cool the compressed first fluorocarbon refrigerant, thereby producing an expanded and cooled first fluorocarbon refrigerant;
Passing the expanded and cooled first fluorocarbon refrigerant through a first heat exchange region;
Natural gas may be compressed,
The natural gas may be cooled by indirect heat exchange with an external cooling fluid, and the natural gas is heat exchanged with an expanded and cooled first fluorocarbon refrigerant, The method of any of paragraphs 20-22.

24. Cooling the natural gas in the second fluorocarbon refrigeration system,
Compressing the second fluorocarbon refrigerant to provide a compressed second fluorocarbon refrigerant;
The compressed second fluorocarbon refrigerant may be cooled by indirect heat exchange with the cooling fluid;
Expanding the compressed second fluorocarbon refrigerant to cool the compressed second fluorocarbon refrigerant, thereby generating an expanded and cooled second fluorocarbon refrigerant;
Passing the expanded and cooled second fluorocarbon refrigerant through a first heat exchange region;
Natural gas may be compressed,
The natural gas may be cooled by indirect heat exchange with an external cooling fluid, and the natural gas may be heat exchanged with an expanded and cooled second fluorocarbon refrigerant, The method of any of paragraphs 20-23.

25. The method of any of paragraphs 20-24, comprising maintaining the nitrogen refrigerant of the nitrogen refrigeration system in a gas phase using one or more expansion turbines.
26. Any of paragraphs 20-25, comprising cooling natural gas in the first fluorocarbon refrigeration system or the second fluorocarbon refrigeration system, or both, using two or more refrigeration stages. That way.
27. The method of any of paragraphs 20 through 26, comprising liquefying natural gas in a nitrogen refrigeration system using one or more refrigeration stages.
28. Using the heat exchanger to cool the first fluorocarbon refrigerant of the first fluorocarbon refrigeration system, the second fluorocarbon refrigerant of the second fluorocarbon refrigeration system, or both; The method of any of paragraphs 20-27, comprising.
29. 29. The method of any of paragraphs 20 through 28, comprising cooling the nitrogen refrigerant of the nitrogen refrigeration system using a heat exchanger.

30. A first refrigeration system configured to cool natural gas using a first fluorocarbon refrigerant, the indirect heat exchange between the natural gas and the first fluorocarbon refrigerant A first refrigeration system comprising a number of first heat exchangers configured to cool natural gas via
A second refrigeration system configured to cool natural gas using a second fluorocarbon refrigerant, wherein indirect heat exchange between the natural gas and the second fluorocarbon refrigerant is performed. A second refrigeration system comprising a number of second heat exchangers configured to cool natural gas via
A third refrigeration system configured to form LNG from natural gas using nitrogen refrigerant, which can cool natural gas through indirect heat exchange between natural gas and nitrogen refrigerant Forming a liquefied natural gas (LNG), including a third refrigeration system including a number of third heat exchangers configured to, and a nitrogen removal unit configured to remove nitrogen from the LNG For hydrocarbon treatment system.

31. The hydrocarbon treatment system of paragraph 30, wherein the nitrogen refrigerant is in a gas phase.
32. The first heat exchanger cools the natural gas by at least partially evaporating the first fluorocarbon refrigerant via transfer of heat from the natural gas to the first fluorocarbon refrigerant. 32. The hydrocarbon treatment system of any of paragraphs 30 or 31, comprising an evaporator configured.
33. The second heat exchanger is configured to cool the natural gas by at least partially vaporizing the second fluorocarbon refrigerant through the transfer of heat from the natural gas to the second fluorocarbon refrigerant. 33. The hydrocarbon treatment system of any of paragraphs 30-32, comprising an evaporator that is

34. A first fluorocarbon refrigeration system configured to cool natural gas using a first fluorocarbon refrigerant;
A second fluorocarbon refrigeration system configured to further cool the natural gas using the second fluorocarbon refrigerant, and methane auto configured to cool the natural gas and generate LNG A hydrocarbon processing system for forming liquefied natural gas (LNG), including a refrigeration system.

35. The hydrocarbon treatment system of paragraph 34, comprising a nitrogen removal unit upstream of the methane automatic refrigeration system.
36. 36. The hydrocarbon treatment system of either paragraph 34 or 35, wherein the methane automatic refrigeration system includes multiple expansion valves and multiple flash tanks.

Various modifications and alternatives may be made to the technology of the present invention, and the embodiments discussed herein are given by way of example only. However, it should be understood again that the techniques of the present invention are not limited to the specific embodiments disclosed herein. Indeed, the technology of the invention includes all alternatives, modifications and equivalents falling within the true spirit and scope of the appended claims.
Another aspect of the present invention may be as follows.
[1] A first fluorocarbon refrigeration system configured to cool natural gas using a first fluorocarbon refrigerant,
A second fluorocarbon refrigeration system configured to further cool natural gas using a second fluorocarbon refrigerant;
A nitrogen refrigeration system configured to cool natural gas using a nitrogen refrigerant to produce LNG; and
Nitrogen removal unit configured to remove nitrogen from LNG
A hydrocarbon processing system for forming liquefied natural gas (LNG).
[2] The hydrocarbon treatment system according to [1], wherein the first fluorocarbon refrigeration system is configured to cool the second fluorocarbon refrigerant of the second fluorocarbon refrigeration system. .
[3] The carbonization according to [1], wherein the first fluorocarbon refrigeration system, the second fluorocarbon refrigeration system, or both are configured to cool a nitrogen refrigerant of the nitrogen refrigeration system. Hydrogen treatment system.
[4] The hydrocarbon treatment system according to [1], wherein the first fluorocarbon refrigeration system, the second fluorocarbon refrigeration system, or both include a plurality of cooling cycles.
[5] The nitrogen refrigeration system includes a plurality of heat exchangers configured to cool the natural gas through indirect heat exchange between the natural gas and the nitrogen refrigerant. Hydrocarbon treatment system.
[6] The first fluorocarbon refrigeration system is
A compressor configured to compress the first fluorocarbon refrigerant to provide a compressed first fluorocarbon refrigerant;
A cooling device configured to cool the compressed first fluorocarbon refrigerant by indirect heat exchange with a cooling fluid;
Configured to expand the compressed first fluorocarbon refrigerant to cool the compressed first fluorocarbon refrigerant, thereby producing a cooled first fluorocarbon refrigerant. Valve, and
A heat exchanger configured to cool natural gas via indirect heat exchange with a cooled first fluorocarbon refrigerant.
The hydrocarbon treatment system according to [1], including:
[7] The second fluorocarbon refrigeration system is
A compressor configured to compress the second fluorocarbon refrigerant to provide a compressed second fluorocarbon refrigerant;
A cooling device configured to cool the compressed second fluorocarbon refrigerant by indirect heat exchange with a cooling fluid;
Configured to expand the compressed second fluorocarbon refrigerant and to cool the compressed second fluorocarbon refrigerant, thereby producing a cooled second fluorocarbon refrigerant. Valve, and
A heat exchanger configured to cool natural gas via indirect heat exchange with a cooled second fluorocarbon refrigerant.
The hydrocarbon treatment system according to [1], including:
[8] The hydrocarbon treatment system according to [1], wherein the first fluorocarbon refrigerant includes R-410A.
[9] The hydrocarbon treatment system according to [1], wherein the second fluorocarbon refrigerant includes R-508B.
[10] The hydrocarbon treatment system according to [1], wherein the first fluorocarbon refrigerant, the second fluorocarbon refrigerant, or both include a non-toxic nonflammable refrigerant.
[11] The carbonization according to [1], wherein the first fluorocarbon refrigeration system, the second fluorocarbon refrigeration system, or both include two or more cooling devices and two or more compressors. Hydrogen treatment system.
[12] The hydrocarbon treatment system according to [1], wherein the first fluorocarbon refrigeration system and the second fluorocarbon refrigeration system are implemented in series.
[13] The hydrocarbon treatment system according to [1], wherein the nitrogen refrigerant is in a gas phase.
[14] The hydrocarbon processing system according to [1], wherein the nitrogen refrigeration system includes two or more cooling devices, two or more expanders, and two or more compressors.
[15] The hydrocarbon treatment system according to [1], which is configured to cool natural gas in order to control a dew point of the hydrocarbon.
[16] The hydrocarbon treatment system according to [1], configured to cool natural gas in order to extract a natural gas liquid.
[17] The hydrocarbon treatment system according to [1], configured to separate methane and lighter gas from carbon dioxide and heavier gas.
[18] The hydrocarbon treatment system according to [1], which is configured to prepare hydrocarbons in order to generate and store liquefied petroleum gas.
[19] The hydrocarbon treatment system according to [1], configured to condense the reflux stream.
[20] cooling the natural gas with the first fluorocarbon refrigeration system;
Cooling natural gas in a second fluorocarbon refrigeration system;
Liquefying natural gas in a nitrogen refrigeration system to form LNG;
Removing nitrogen from LNG with a nitrogen removal unit;
A method for forming liquefied natural gas (LNG).
[21] The method according to [20], including the step of cooling the second fluorocarbon refrigerant of the second fluorocarbon refrigeration system in the first fluorocarbon refrigeration system.
[22] The method according to [20], including the step of cooling the nitrogen refrigerant of the nitrogen refrigeration system in the first fluorinated carbon refrigeration system, the second fluorinated carbon refrigeration system, or both.
[23] The step of cooling natural gas in the first fluorocarbon refrigeration system comprises:
Compressing the first fluorocarbon refrigerant to provide a compressed first fluorocarbon refrigerant; indirect heat exchange with the cooling fluid for the compressed first fluorocarbon refrigerant; Can be cooled,
Expanding the compressed first fluorocarbon refrigerant to cool the compressed first fluorocarbon refrigerant, thereby producing an expanded and cooled first fluorocarbon refrigerant;
Passing the expanded and cooled first fluorocarbon refrigerant through a first heat exchange region, compressing natural gas,
Natural gas may be cooled by indirect heat exchange with an external cooling fluid, and
Heat exchanging natural gas with the expanded and cooled first fluorocarbon refrigerant
The method according to [20] above, comprising:
[24] The step of cooling natural gas in the second fluorocarbon refrigeration system comprises:
Compressing the second fluorocarbon refrigerant to provide a compressed second fluorocarbon refrigerant; and compressing the second fluorocarbon refrigerant by indirect heat exchange with the cooling fluid. Can be cooled,
Expanding the compressed second fluorocarbon refrigerant to cool the compressed second fluorocarbon refrigerant, thereby generating an expanded and cooled second fluorocarbon refrigerant;
Passing the expanded and cooled second fluorocarbon refrigerant through the first heat exchange region, compressing natural gas,
Natural gas may be cooled by indirect heat exchange with an external cooling fluid, and
Heat exchanging natural gas with the expanded and cooled second fluorocarbon refrigerant
The method according to [20] above, comprising:
[25] The method according to [20], including the step of maintaining the nitrogen refrigerant of the nitrogen refrigeration system in a gas phase state using one or more expansion turbines.
[26] In the above [20], including cooling natural gas in the first fluorocarbon refrigeration system or the second fluorocarbon refrigeration system, or both using two or more refrigeration stages The method described.
[27] The method according to [20], comprising liquefying natural gas in a nitrogen refrigeration system using one or more refrigeration stages.
[28] A first refrigeration system configured to cool natural gas using a first fluorocarbon refrigerant, the indirect between the natural gas and the first fluorocarbon refrigerant A first refrigeration system including a plurality of first heat exchangers configured to cool natural gas via a secure heat exchange;
A second refrigeration system configured to cool natural gas using a second fluorocarbon refrigerant, wherein indirect heat exchange between the natural gas and the second fluorocarbon refrigerant is performed. A second refrigeration system comprising a plurality of second heat exchangers configured to cool natural gas via
A third refrigeration system configured to form LNG from natural gas using nitrogen refrigerant, which can cool natural gas through indirect heat exchange between natural gas and nitrogen refrigerant A third refrigeration system including a plurality of third heat exchangers configured as described above, and
Nitrogen removal unit configured to remove nitrogen from LNG
A hydrocarbon processing system for forming liquefied natural gas (LNG).
[29] The hydrocarbon treatment system according to [28], wherein the nitrogen refrigerant is in a gas phase.
[30] A plurality of first heat exchangers at least partially vaporize the first fluorocarbon refrigerant through the transfer of heat from the natural gas to the first fluorocarbon refrigerant. The hydrocarbon treatment system according to [28], further including an evaporator configured to cool the gas.
[31] The plurality of second heat exchangers at least partially vaporize the second fluorocarbon refrigerant through the transfer of heat from the natural gas to the second fluorocarbon refrigerant. The hydrocarbon treatment system according to [28], further including an evaporator configured to cool the water.
[32] a first fluorocarbon refrigeration system configured to cool natural gas using the first fluorocarbon refrigerant;
A second fluorocarbon refrigeration system configured to further cool natural gas using a second fluorocarbon refrigerant; and
Methane automatic refrigeration system configured to cool natural gas and generate LNG
A hydrocarbon processing system for forming liquefied natural gas (LNG).
[33] The hydrocarbon treatment system according to [32], further including a nitrogen removal unit upstream of the methane automatic refrigeration system including a plurality of expansion valves and a plurality of flash tanks.

Claims (20)

A first fluorocarbon refrigeration system configured to cool natural gas using a first fluorocarbon refrigerant,
A compressor configured to compress the first fluorocarbon refrigerant to provide a compressed first fluorocarbon refrigerant;
A cooling device configured to cool the compressed first fluorocarbon refrigerant by indirect heat exchange with a cooling fluid;
The compressed first fluorocarbon refrigerant is expanded to cool the compressed first fluorocarbon refrigerant, thereby producing a cooled first fluorocarbon refrigerant. With a valve,
Wherein the cooled vapor portion of the first fluorocarbon refrigerant, is configured to separate said cooled liquid portion of the first fluorocarbon refrigerant vapor portion of the first fluorocarbon refrigerant Is a saving device introduced into the compressor ;
A heat exchanger configured to cool natural gas via indirect heat exchange with the liquid portion of the cooled first fluorocarbon refrigerant;
A first fluorocarbon refrigeration system, comprising:
A second fluorocarbon refrigeration system configured to further cool natural gas using a second fluorocarbon refrigerant;
Liquefied natural gas, comprising a nitrogen refrigeration system configured to cool natural gas using nitrogen refrigerant to produce LNG, and a nitrogen removal unit configured to remove nitrogen from LNG LNG) hydrocarbon treatment system.   The hydrocarbon treatment system of claim 1, wherein the first fluorocarbon refrigeration system is configured to cool the second fluorocarbon refrigerant of the second fluorocarbon refrigeration system.   The hydrocarbon treatment system of claim 1, wherein the first fluorinated carbon refrigeration system or the second fluorinated carbon refrigeration system, or both, is configured to cool the nitrogen refrigerant of the nitrogen refrigeration system.   The hydrocarbon treatment system of claim 1, wherein the first fluorocarbon refrigeration system or the second fluorocarbon refrigeration system, or both, comprises a plurality of refrigeration cycles.   The hydrocarbon treatment of claim 1, wherein the nitrogen refrigeration system includes a plurality of heat exchangers configured to cool the natural gas via indirect heat exchange between the natural gas and the nitrogen refrigerant. system. The second fluorocarbon refrigeration system
A compressor configured to compress the second fluorocarbon refrigerant to provide a compressed second fluorocarbon refrigerant;
A cooling device configured to cool the compressed second fluorocarbon refrigerant by indirect heat exchange with a cooling fluid;
Configured to expand the compressed second fluorocarbon refrigerant and to cool the compressed second fluorocarbon refrigerant, thereby producing a cooled second fluorocarbon refrigerant. And a heat exchanger configured to cool natural gas via indirect heat exchange with a cooled second fluorocarbon refrigerant. Processing system.   The hydrocarbon treatment system of claim 1, wherein the first fluorocarbon refrigerant comprises R-410A.   The hydrocarbon treatment system of claim 1, wherein the second fluorocarbon refrigerant comprises R-508B.   The hydrocarbon treatment system of claim 1, wherein the first or second fluorocarbon refrigerant, or both, comprises a non-toxic non-flammable refrigerant.   The hydrocarbon processing system of claim 1, wherein the first fluorocarbon refrigeration system or the second fluorocarbon refrigeration system, or both, includes two or more chillers and two or more compressors.   The hydrocarbon treatment system of claim 1, wherein the first fluorocarbon refrigeration system and the second fluorocarbon refrigeration system are implemented in series.   The hydrocarbon treatment system according to claim 1, wherein the nitrogen refrigerant is in a gas phase.   The hydrocarbon processing system of claim 1, wherein the nitrogen refrigeration system comprises two or more chillers, two or more expanders, and two or more compressors. Cooling the natural gas with a first fluorocarbon refrigeration system comprising:
Compressing the first fluorocarbon refrigerant to provide a compressed first fluorocarbon refrigerant;
The compressed first fluorocarbon refrigerant may be cooled by indirect heat exchange with a cooling fluid;
Expanding the compressed first fluorocarbon refrigerant to cool the compressed first fluorocarbon refrigerant, thereby producing an expanded and cooled first fluorocarbon refrigerant; When,
Separating a vapor portion of the expanded and cooled first fluorocarbon refrigerant from a liquid portion of the expanded and cooled first fluorocarbon refrigerant in a conserving device;
Passing the expanded and cooled liquid portion of the first fluorocarbon refrigerant through a first heat exchange region ;
Introducing the vapor portion of the expanded and cooled first fluorocarbon refrigerant into a compressor that also compresses the first fluorocarbon refrigerant;
Natural gas may be compressed,
Natural gas may be cooled by indirect heat exchange with an external cooling fluid, and natural gas is heat exchanged using the expanded and cooled liquid portion of the first fluorocarbon refrigerant. And
Including steps,
Cooling natural gas in a second fluorocarbon refrigeration system;
Liquefying natural gas in a nitrogen refrigeration system to form LNG;
Removing nitrogen from the LNG with a nitrogen removal unit. A method for forming liquefied natural gas (LNG).   The method of claim 14, comprising cooling the second fluorocarbon refrigerant of the second fluorocarbon refrigeration system in the first fluorocarbon refrigeration system.   15. The method of claim 14, comprising cooling the nitrogen refrigerant of the nitrogen refrigeration system within the first fluorinated carbon refrigeration system or the second fluorinated carbon refrigeration system, or both. Cooling the natural gas in the second fluorocarbon refrigeration system,
Compressing the second fluorocarbon refrigerant to provide a compressed second fluorocarbon refrigerant; and compressing the second fluorocarbon refrigerant by indirect heat exchange with the cooling fluid. Can be cooled,
Expanding the compressed second fluorocarbon refrigerant to cool the compressed second fluorocarbon refrigerant, thereby generating an expanded and cooled second fluorocarbon refrigerant;
Passing the expanded and cooled second fluorocarbon refrigerant through the first heat exchange region, compressing natural gas,
The natural gas may be cooled by indirect heat exchange with an external cooling fluid, and the natural gas is heat exchanged with an expanded and cooled second fluorocarbon refrigerant, The method according to claim 14.   The method of claim 14, comprising maintaining the nitrogen refrigerant of the nitrogen refrigeration system in a gas phase using one or more expansion turbines.   15. The method of claim 14, comprising cooling natural gas in the first fluorocarbon refrigeration system or the second fluorocarbon refrigeration system, or both, using two or more refrigeration stages.   15. The method of claim 14, comprising liquefying natural gas in a nitrogen refrigeration system using one or more refrigeration stages.

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