CN115232657B - Device and method for recycling C2+ by utilizing LNG cold energy - Google Patents

Device and method for recycling C2+ by utilizing LNG cold energy Download PDF

Info

Publication number
CN115232657B
CN115232657B CN202210973645.8A CN202210973645A CN115232657B CN 115232657 B CN115232657 B CN 115232657B CN 202210973645 A CN202210973645 A CN 202210973645A CN 115232657 B CN115232657 B CN 115232657B
Authority
CN
China
Prior art keywords
lng
demethanizer
channel
natural gas
heat exchanger
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202210973645.8A
Other languages
Chinese (zh)
Other versions
CN115232657A (en
Inventor
王振华
金海刚
崔世华
杨涛
张超
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
China National Offshore Oil Corp CNOOC
CNOOC Petrochemical Engineering Co Ltd
CNOOC Oil and Petrochemicals Co Ltd
Original Assignee
China National Offshore Oil Corp CNOOC
CNOOC Petrochemical Engineering Co Ltd
CNOOC Oil and Petrochemicals Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by China National Offshore Oil Corp CNOOC, CNOOC Petrochemical Engineering Co Ltd, CNOOC Oil and Petrochemicals Co Ltd filed Critical China National Offshore Oil Corp CNOOC
Priority to CN202210973645.8A priority Critical patent/CN115232657B/en
Publication of CN115232657A publication Critical patent/CN115232657A/en
Application granted granted Critical
Publication of CN115232657B publication Critical patent/CN115232657B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
    • C10L3/12—Liquefied petroleum gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0238—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 2 carbon atoms or more
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L3/00—Gaseous fuels; Natural gas; Synthetic natural gas obtained by processes not covered by subclass C10G, C10K; Liquefied petroleum gas
    • C10L3/06—Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04
    • C10L3/10—Working-up natural gas or synthetic natural gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
    • F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
    • F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
    • F25J1/0279—Compression of refrigerant or internal recycle fluid, e.g. kind of compressor, accumulator, suction drum etc.
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0204—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the feed stream
    • F25J3/0209—Natural gas or substitute natural gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0204—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the feed stream
    • F25J3/0209—Natural gas or substitute natural gas
    • F25J3/0214—Liquefied natural gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
    • F25J3/0233—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 1 carbon atom or more
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/02—Processes or apparatus using separation by rectification in a single pressure main column system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/40—Features relating to the provision of boil-up in the bottom of a column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/50—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/70—Refluxing the column with a condensed part of the feed stream, i.e. fractionator top is stripped or self-rectified
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/72—Refluxing the column with at least a part of the totally condensed overhead gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/02—Processes or apparatus using other separation and/or other processing means using simple phase separation in a vessel or drum
    • F25J2205/04—Processes or apparatus using other separation and/or other processing means using simple phase separation in a vessel or drum in the feed line, i.e. upstream of the fractionation step
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2210/00—Processes characterised by the type or other details of the feed stream
    • F25J2210/02—Multiple feed streams, e.g. originating from different sources
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2260/00—Coupling of processes or apparatus to other units; Integrated schemes
    • F25J2260/02—Integration in an installation for exchanging heat, e.g. for waste heat recovery
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
    • F25J2290/34—Details about subcooling of liquids

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Separation By Low-Temperature Treatments (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)

Abstract

The invention relates to the technical field of natural gas processing, in particular to a device and a method for recycling C2+ by utilizing LNG cold energy. The device comprises an LNG recycling C2+ system and a natural gas recycling C2+ system; during operation, the raw material LNG enters an LNG recovery C2+ system, and a recovery flow of C2+ components in the raw material LNG is completed in the LNG recovery C2+ system; the raw natural gas enters a natural gas recovery C2+ system, and a recovery flow of C2+ components in the raw natural gas is completed in the natural gas recovery C2+ system. The device and the method provided by the invention realize linkage coordination of the LNG recycling C2+ system and the natural gas recycling C2+ system, can simultaneously recycle the raw material LNG and the C2+ components in the raw material natural gas, reduce the labor force and the occupied area of an operator, and have the advantages of high LNG cold energy utilization rate, high recovery rate of the C2+ components, low energy consumption and low cost.

Description

Device and method for recycling C2+ by utilizing LNG cold energy
Technical Field
The invention relates to the technical field of natural gas processing, in particular to a device and a method for recycling C2+ by utilizing LNG cold energy.
Background
Liquefied natural gas (Liquefied Natural Gas, LNG) is a liquid that is converted into natural gas after it has been compressed and cooled to a temperature at its congealing point (-162 c), and regasified when in use. When LNG is vaporized to the ambient temperature, the discharged cold energy is 840kJ/kg, and the cold energy is discharged through an LNG seawater vaporizer or air, so that the cold energy is wasted greatly. Therefore, the cold energy released in the LNG vaporization process is utilized to recycle the C2+ in the LNG, so that the LNG vaporization load is reduced, the energy consumption for recycling the C2+ is reduced, and the LNG vaporization process has extremely high industrial application value. In the prior art, when LNG cold energy is utilized to recycle C2+, LNG is firstly conveyed to a cold box for heat exchange and then enters a flash tank; and part of flash steam generated at the top of the flash tank and LNG flash liquid generated at the bottom of the flash tank enter a demethanizer to remove most of methane in the flash steam to obtain a C2+ product and a C2+ LNG product. In the process, the surplus cold energy of LNG flash liquid at the bottom of the flash tank cannot be effectively utilized, so that the cold energy is wasted.
Disclosure of Invention
The first object of the present invention is to provide a device for recovering c2+ using LNG cold energy, so as to solve the problem of LNG cold energy waste in the prior art.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
a device for recycling C2+ by utilizing LNG cold energy comprises an LNG recycling C2+ system and a natural gas recycling C2+ system;
The LNG recovery C2+ system comprises a first cold box, a second cold box, a first flash tank and a first demethanizer; the first cooling box comprises a first LNG channel and a flash evaporation gas channel, wherein an inlet of the first LNG channel is used for receiving raw material LNG, and an inlet of the flash evaporation gas channel is communicated with a discharge port at the top of the first flash evaporation tank; the second cooling box comprises a second LNG channel and a first tower top gas channel, and an inlet of the first tower top gas channel is communicated with a discharge port at the top of the first demethanizer;
The natural gas recovery c2+ system comprises a second demethanizer, a third cold box, and a reflux drum, wherein the second demethanizer is capable of receiving raw natural gas; the third cooling box comprises a second tower top gas channel and a third LNG channel, and the second demethanizer, the second tower top gas channel and the reflux tank are sequentially communicated end to form a closed loop;
The first LNG channel, the second LNG channel, the first flash tank, the third LNG channel and the first demethanizer are sequentially communicated.
Further, a first tower bottom heat exchanger is arranged at the bottom of the second demethanizer, and comprises a first heat exchanger channel and a second heat exchanger channel; the inlet and the outlet of the first heat exchanger channel are respectively communicated with a discharge port and a feed port at the lower end of the second demethanizer; the inlet of the second heat exchanger channel is used for receiving natural gas, and the outlet of the second heat exchanger channel is communicated with the feed inlet of the second demethanizer.
Further, the natural gas recovery C2+ system further comprises a fourth cold box, wherein the fourth cold box comprises a natural gas channel and a third tower top gas channel, an inlet of the natural gas channel is communicated with an outlet of the second heat exchanger channel, and an outlet of the natural gas channel is communicated with a feed inlet of the second demethanizer; and the inlet of the third tower top gas channel is communicated with the discharge port of the top of the second demethanizer.
Further, the LNG recovery c2+ system further comprises a condensing tank, the third cold box further comprises a fourth LNG channel, and the fourth cold box further comprises a fifth LNG channel; the first demethanizer, the first overhead gas channel, the condensate tank, the fourth LNG channel, and the fifth LNG channel are sequentially connected.
Further, the device also comprises a middle section circulation structure, wherein the middle section circulation structure comprises a middle section circulation pump and a middle section circulation heat exchanger;
the input end of the middle section circulating pump is connected with a discharge port in the middle of the first demethanizer, the output end of the middle section circulating pump is provided with a first branch and a second branch, the output ends of the first branch and the second branch are respectively connected with two feed inlets in the middle of the first demethanizer, and the second branch is provided with the middle section circulating heat exchanger; and/or, the input end of the middle section circulating pump is connected to the discharge port in the middle of the second demethanizer, the output end of the middle section circulating pump is provided with a first branch and a second branch, the output ends of the first branch and the second branch are respectively connected to two feed inlets in the middle of the second demethanizer, and the second branch is provided with the middle section circulating heat exchanger.
The second object of the invention is to provide a method for recovering C2+ by utilizing LNG cold energy, so as to solve the problem of LNG cold energy waste in the prior art.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
a method for recovering c2+ by utilizing LNG cold energy, comprising the steps of:
S1: the raw material LNG in the storage tank is boosted through the feed pump, and is subjected to heat exchange in the first cold box and the second cold box in sequence, and enters the first flash tank after heat exchange;
The raw material natural gas enters a second demethanizer;
S2: the flash gas generated at the top of the first flash tank returns to the first cold box for heat exchange and liquefaction, and enters the second flash tank after being liquefied;
detecting the concentration of C2+ in the liquid phase discharged from the bottom of the second flash tank, and if the concentration exceeds a set value, entering the first demethanizer;
S3: the LNG flash liquid generated at the bottom of the first flash tank enters a third cold box for heat exchange, and enters a first demethanizer after heat exchange;
detecting the concentration of C2+ in the tower top gas generated by the second demethanizer, and if the concentration exceeds a set value, entering a third cold box for heat exchange; after heat exchange, returning to the second demethanizer through the reflux tank;
S4, fractionating the flash gas partially liquefied in the step 2 and the LNG flash liquid in the step 3 by a first demethanizer to obtain a C2+ product;
fractionating the raw natural gas and the top gas refluxed in the step 3 by a second demethanizer to obtain a C2+ product and a C2+ natural gas product;
S5: the tower top gas generated by the first demethanizer is returned to the second cold box for heat exchange and liquefaction.
In the step 1, the raw material natural gas in a normal temperature state and the bottom component of the second demethanizer exchange heat through a first bottom heat exchanger; and the raw material natural gas subjected to heat exchange enters a fourth cold box to be cooled to be partially liquefied, and then enters a second demethanizer.
Further, in the step 2, if the concentration of c2+ in the liquid phase discharged from the bottom of the second flash tank is lower than a set value, the liquid phase enters a condensing tank; the liquefied top gas discharged from the second cooling box in the step 5 enters a condensing tank; and sequentially discharging liquid phase discharged from the condensing tank after heat exchange in the third cold box and the fourth cold box to obtain a C2-removed LNG product.
In step 3, if the concentration of c2+ in the overhead gas generated by the second demethanizer is lower than a set value, the overhead gas enters the fourth cold box to exchange heat and then is discharged, so as to obtain a natural gas product without c2+.
Further, the middle-section components of the first demethanizer are discharged from a discharge port, pressurized by a middle-section circulating pump, one part of the components returns to the first demethanizer for circulating reaction, and the other part of the components and the glycol water solution exchange heat in a middle-section circulating heat exchanger and then return to the first demethanizer for circulating reaction; and/or the number of the groups of groups,
And the middle-section components of the second demethanizer are discharged from a discharge port, pressurized by a middle-section circulating pump, one part of the components returns to the second demethanizer for circulating reaction, and the other part of the components and the glycol water solution exchange heat in a middle-section circulating heat exchanger and then return to the second demethanizer for circulating reaction.
The invention has the beneficial effects that:
The invention provides a device and a method for recycling C2+ by utilizing LNG cold energy, wherein when the device works, raw material LNG enters an LNG recycling C2+ system, and a recycling process of C2+ components in the raw material LNG is completed in the LNG recycling C2+ system; the raw natural gas enters a natural gas recovery C2+ system, and a recovery flow of C2+ components in the raw natural gas is completed in the natural gas recovery C2+ system. During operation, LNG flash liquid generated at the bottom of the first flash tank and part of tower top gas generated by the second demethanizer enter the third cold box for heat exchange, LNG cold energy can be fully utilized, the purposes of recycling the raw material LNG and C2+ components in the raw material natural gas simultaneously by utilizing the LNG cold energy are achieved, LNG cold energy waste is avoided, and energy consumption and cost are reduced; part of the overhead gas generated by the second demethanizer is cooled in a third cold box until part of the overhead gas is liquefied, and then flows through a reflux tank to return to the second demethanizer for circulating fractionation, so that the recovery rate of the C2+ component is improved; the device and the method provided by the invention realize linkage coordination of the LNG recycling C2+ system and the natural gas recycling C2+ system, can simultaneously recycle the C2+ components in the raw material LNG and the raw material natural gas, and reduce the labor force and the occupied area of an operator.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of an apparatus for recovering c2+ using LNG cold energy according to an embodiment of the present invention;
Fig. 2 is a schematic structural diagram of an LNG recycling c2+ system in an apparatus for recycling c2+ using LNG cold energy according to an embodiment of the present invention;
Fig. 3 is a schematic structural diagram of a natural gas c2+ recovery system in an apparatus for recovering c2+ using LNG cold energy according to an embodiment of the present invention.
Icon:
1-LNG recovery c2+ system; 11-a first cold box; 12-a second cold box; 13-a first flash tank; 14-a first demethanizer; 15-a condensing tank; 16-a second flash tank; 17-a second bottom heat exchanger;
2-a natural gas recovery c2+ system; 21-a second demethanizer; 22-a third cooling box; 23-a reflux drum; 24-a first bottom heat exchanger; 25-fourth cold box;
3-a middle section circulation structure; 31-a middle circulation pump; 32-a middle section circulating heat exchanger; 33-glycol aqueous solution.
41-Feed LNG; 42-raw natural gas; 43-LNG flash; 44-c2+ products; 45-dec2+ natural gas product; 46-DeC2+ LNG product.
Detailed Description
The technical solutions of the present invention will be clearly and completely described in connection with the embodiments, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that, in the description of the present invention, the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
It should be noted that, in the description of the present invention, the terms "connected" and "mounted" should be understood in a broad sense, and for example, may be a fixed connection, a detachable connection, or an integral connection; can be directly connected or connected through an intermediate medium; either mechanically or electrically. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
Example 1
Referring to fig. 1, the present embodiment provides an apparatus for recovering c2+ using LNG cold energy, which includes an LNG recovery c2+ system 1 and a natural gas recovery c2+ system 2; specifically, LNG recovery c2+ system 1 comprises a first cold box 11, a second cold box 12, a first flash tank 13, and a first demethanizer 14; the first cooling tank 11 comprises a first LNG channel and a flash evaporation gas channel, wherein an inlet of the first LNG channel is used for receiving raw LNG, and an inlet of the flash evaporation gas channel is communicated with a discharge port at the top of the first flash tank 13; the second cold box 12 comprises a second LNG channel and a first tower top gas channel, and the inlet of the first tower top gas channel is communicated with a discharge port at the tower top of the first demethanizer 14; the natural gas recovery c2+ system 2 comprises a second demethanizer 21, a third cold box 22, and a reflux drum 23, the second demethanizer 21 being capable of receiving a raw natural gas; the third cooling box 22 comprises a second tower top gas channel and a third LNG channel, and the second demethanizer 21, the second tower top gas channel and the reflux drum 23 are sequentially communicated end to form a closed loop; the first LNG path, the second LNG path, the first flash tank 13, the third LNG path, and the first demethanizer 14 are sequentially connected.
When the device works, raw material LNG enters an LNG recovery C2+ system 1, and a recovery flow of C2+ components in the raw material LNG is completed in the LNG recovery C2+ system 1; the raw natural gas enters a natural gas recovery C2+ system 2, and a recovery flow of C2+ components in the raw natural gas is completed in the natural gas recovery C2+ system 2. The device realizes the linkage cooperation of the LNG recovery C2+ system 1 and the natural gas recovery C2+ system 2, can simultaneously complete the recovery of C2+ components in raw material LNG and raw material natural gas, reduces the labor force and the occupied area of an operator, and has the advantages of high LNG cold energy utilization rate, high recovery rate of the C2+ components, low energy consumption and low cost. Further, the LNG recovery c2+ system 1 and the natural gas recovery c2+ system 2 in the present embodiment may also be operated independently of each other.
Specifically, the recovery flow of c2+ components in LNG is: the raw material LNG in the storage tank is boosted by a feed pump, sequentially exchanges heat with flash gas and demethanizer overhead gas in the first cold box 11 and the second cold box 12 respectively, and then enters the first flash tank 13; the flash gas generated at the top of the first flash tank 13 returns to the first cold box 11, and the LNG flash liquid generated at the bottom of the first flash tank 13 enters the third cold box 22 for heat exchange and then enters the first demethanizer 14; the first demethanizer 14 fractionates the liquid phase entering it to yield a c2+ product. The recovery flow of the C2+ component in the raw natural gas is as follows: the raw natural gas 42 enters the second demethanizer 21 for fractionation; part of the overhead gas generated by the second demethanizer 21 enters a third cold box 22 for heat exchange; after heat exchange, the mixture is returned to the second demethanizer 21 by the reflux drum 23 and booster pump.
In the embodiment, the LNG flash liquid generated at the bottom of the first flash tank 13 and part of the overhead gas generated by the second demethanizer 21 enter the third cooling tank 22 for heat exchange, so that LNG cold energy can be fully utilized, and the purpose of simultaneously recycling c2+ components in raw LNG and raw natural gas by utilizing the LNG cold energy is achieved, thereby avoiding LNG cold energy waste and reducing energy consumption; part of the overhead gas produced in the second demethanizer 21 is cooled to a partial liquefaction and then returned to the second demethanizer 21 for cyclic fractionation, thereby increasing the recovery of the c2+ components.
Further, a first bottom heat exchanger 24 is disposed at the bottom of the second demethanizer 21, and the first bottom heat exchanger 24 includes a first heat exchanger channel and a second heat exchanger channel; the inlet and the outlet of the first heat exchanger channel are respectively communicated with a discharge port and a feed port at the lower end of the second demethanizer 21; the inlet of the second heat exchanger channel is used for receiving natural gas, and the outlet of the second heat exchanger channel is communicated with the feed inlet of the second demethanizer 21. By arranging the first tower bottom heat exchanger 24, raw natural gas in a normal temperature state can be used as a heat source at the bottom of the demethanizer to heat the tower bottom components of the demethanizer, so that a heat source is not required to be additionally arranged, and the cost is reduced; and the bottom component plays a certain role in cooling the raw material natural gas.
Further, the natural gas recovery c2+ system 2 further comprises a fourth cold box 25, the fourth cold box 25 comprises a natural gas channel and a third tower top gas channel, an inlet of the natural gas channel is communicated with an outlet of the second heat exchanger channel, and an outlet of the natural gas channel is communicated with a feed inlet of the second demethanizer 21; the inlet of the third overhead gas channel is connected to the outlet of the top of the second demethanizer 21.
Based on the above structure, the LNG recycling c2+ system 1 further includes a condensation tank 15, the third cooling tank 22 further includes a fourth LNG channel, and the fourth cooling tank 25 further includes a fifth LNG channel; the first demethanizer 14, the first overhead gas passage, the condensate tank 15, the fourth LNG passage, and the fifth LNG passage are in communication in sequence. In operation, the overhead gas from the first demethanizer 14 enters the first overhead gas path of the second cold box 12, exchanges heat with LNG discharged from the first cold box 11 and liquefies, and then enters the condensing tank 15; the liquid phase (the c2+ LNG-depleted product) discharged from the condensation tank 15 is subjected to heat exchange in the third cooling tank 22 and the fourth cooling tank 25 in this order.
In this embodiment, a part of the overhead gas generated in the second demethanizer 21, the LNG flash liquid generated in the bottom of the first flash tank 13, and the liquid phase (the product of removing c2+ LNG) discharged from the condensation tank 15 exchange heat in the third cooling tank 22; another portion of the overhead gas produced by the second demethanizer 21, the raw natural gas exiting the first bottoms heat exchanger 24, and the liquid phase exiting the third cold box 22 (the decarbonized c2+ LNG product) are heat exchanged in the fourth cold box 25. The device novel structure can make full use of LNG cold energy to retrieve C2+ component in raw materials LNG and the raw materials natural gas, reduces the energy consumption.
Referring to fig. 2, the lower end of the first demethanizer 14 is provided with a second bottom heat exchanger 17. The bottom of the first demethanizer 14 uses low pressure steam as a reboiler heat source; specifically, the steam of 0.6MPag and the bottom component of the first demethanizer 14 enter a second bottom heat exchanger 17 for heat exchange; the vapor condenses into water and exits the second bottom heat exchanger 17 with the bottom components of the first demethanizer 14 being returned to the bottom of the first demethanizer 14.
Further, the LNG recovery c2+ system 1 further comprises a second flash tank 16; the outlet of the flash gas channel is communicated with the feed inlet of the second flash tank 16, and the discharge outlet at the bottom of the second flash tank 16 is provided with two branches, wherein one branch is communicated with the feed inlet of the first demethanizer 14, and the other branch is communicated with the feed inlet of the condensing tank 15. The first demethanizer 14 introduces a portion of the flash gas condensate as a reflux stream to increase recovery of the c2+ components; and, the second flash tank 16 can further flash condensate entering the second flash tank, so that the content of C2+ components in the liquid phase at the bottom of the second flash tank 16 is improved, and the recovery rate of the C2+ components is further improved.
Referring to fig. 2 and 3, the apparatus provided in this embodiment further includes a middle circulation structure 3, and the middle circulation structure 3 includes a middle circulation pump 31 and a middle circulation heat exchanger 32; the input end of the middle section circulating pump 31 is connected to the discharge port in the middle of the first demethanizer 14, the output end of the middle section circulating pump 31 is provided with a first branch and a second branch, the output ends of the first branch and the second branch are respectively connected to two feed inlets in the middle of the first demethanizer 14, and the second branch is provided with a middle section circulating heat exchanger 32; and/or, the input end of the middle section circulating pump 31 is connected to the discharge port in the middle of the second demethanizer 21, the output end of the middle section circulating pump 31 is provided with a first branch and a second branch, the output ends of the first branch and the second branch are respectively connected to two feed inlets in the middle of the second demethanizer 21, and the second branch is provided with a middle section circulating heat exchanger 32. By arranging the middle-section circulating structure 3, the recovery rate of the C2+ component is improved.
Example two
Referring to fig. 1 to 3, the present embodiment provides a method for recovering c2+ using LNG cold energy, the method comprising the steps of:
S1: the raw material LNG41 in the storage tank is boosted by a feed pump, and sequentially exchanges heat in the first cold box 11 and the second cold box 12, and enters the first flash tank 13 after exchanging heat;
The raw natural gas 42 enters the second demethanizer 21;
s2: the flash gas generated at the top of the first flash tank 13 returns to the first cold box 11 for heat exchange and liquefaction, and enters the second flash tank 16 after being liquefied;
Detecting the concentration of C2+ in the liquid phase withdrawn from the bottom of the second flash tank 16, and if the concentration exceeds a set point, entering the first demethanizer 14;
S3: the LNG flash liquid 43 generated at the bottom of the first flash tank 13 enters the third cold box 22 for heat exchange, and enters the first demethanizer 14 after heat exchange;
Detecting the concentration of C2+ in the overhead gas generated by the second demethanizer 21, and if the concentration exceeds a set value, entering a third cold box 22 for heat exchange; after heat exchange, the mixture is returned to the second demethanizer 21 through a reflux drum 23;
s4, fractionating the flash gas partially liquefied in the step 2 and the LNG flash liquid 43 in the step 3 by the first demethanizer 14 to obtain a C2+ product 44;
The second demethanizer 21 fractionates the feed natural gas 42 and the overhead gas refluxed in step 3 to yield a c2+ product 44 and a decarbonized natural gas product 45;
S5: the overhead gas from the first demethanizer 14 is returned to the second cold box 12 for heat exchange and liquefaction.
In the step 1, the raw material natural gas 42 in a normal temperature state and the bottom component of the second demethanizer 21 exchange heat through the first bottom heat exchanger 24, and serve as a bottom heat source of the demethanizer to heat the bottom component of the second demethanizer 21; the heat exchanged raw natural gas 42 enters the fourth cold box 25 to be cooled to partially liquefy and then enters the second demethanizer 21.
In step 2, if the concentration of c2+ in the liquid phase discharged from the bottom of the second flash tank 16 is lower than a set value, the liquid phase enters a condensation tank 15; the liquefied top gas discharged from the second cooling tank 12 in the step 5 enters a condensing tank 15; the liquid phase discharged from the condensation tank 15 is sequentially discharged after heat exchange in the third and fourth cold tanks 22 and 25, and a c2+ LNG product 46 is obtained.
In step 3, if the concentration of c2+ in the overhead gas generated in the second demethanizer 21 is lower than the set value, the overhead gas enters the fourth cold box 25 to exchange heat and then is discharged, so as to obtain a natural gas product 45 with the concentration of c2+ removed.
Further, the middle-section component of the first demethanizer 14 is discharged from the discharge port, pressurized by the middle-section circulating pump 31, and a part of the component returns to the first demethanizer 14 for circulating reaction, and the other part of the component and the glycol aqueous solution 33 exchange heat in the middle-section circulating heat exchanger 32 and then returns to the first demethanizer 14 for circulating reaction; and/or, the middle-section component of the second demethanizer 21 is discharged from the discharge port, pressurized by the middle-section circulating pump 31, and a part of the component returns to the second demethanizer 21 for circulating reaction, and the other part of the component and the glycol aqueous solution 33 exchange heat in the middle-section circulating heat exchanger 32 and then returns to the second demethanizer 21 for circulating reaction.
Further, since the CO2 component in the raw natural gas 42 is too high in proportion, the problem of freeze blocking easily occurs in the column, and therefore the CO2 component in the raw natural gas 42 is not preferably too high in proportion. A detection process may be provided to detect the proportion of CO2 components in the raw natural gas 42 before the raw natural gas 42 enters the first bottom heat exchanger 24.
The method for recycling the C2+ by utilizing the LNG cold energy provided by the invention can fully utilize the LNG cold energy, can simultaneously recycle the raw material LNG and the C2+ components in the raw material natural gas, and has the advantages of high recovery rate of the C2+, simple process flow, low energy consumption and low cost.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims (9)

1. The device for recycling the C2+ by utilizing the LNG cold energy is characterized by comprising an LNG recycling C2+ system (1) and a natural gas recycling C2+ system (2);
The LNG recovery C2+ system (1) comprises a first cold box (11), a second cold box (12), a first flash tank (13) and a first demethanizer (14); the first cold box (11) comprises a first LNG channel and a flash evaporation gas channel, the inlet of the first LNG channel is used for receiving raw LNG, and the inlet of the flash evaporation gas channel is communicated with a discharge port at the top of the first flash evaporation tank (13); the second cooling box (12) comprises a second LNG channel and a first tower top gas channel, and an inlet of the first tower top gas channel is communicated with a discharge port at the top of the first demethanizer (14);
The natural gas recovery c2+ system (2) comprises a second demethanizer (21), a third cold box (22), and a reflux drum (23), the second demethanizer (21) being capable of receiving a feed natural gas; the third cooling box (22) comprises a second tower top gas channel and a third LNG channel, and the second demethanizer (21), the second tower top gas channel and the reflux tank (23) are sequentially communicated end to form a closed loop;
the first LNG channel, the second LNG channel, the first flash tank (13), the third LNG channel and the first demethanizer (14) are sequentially communicated;
the natural gas recovery C2+ system (2) further comprises a fourth cold box (25);
the LNG recovery C2+ system (1) further comprises a condensing tank (15), and the third cold box (22) further comprises a fourth LNG channel; the fourth cold box (25) further comprises a fifth LNG channel, and the first demethanizer (14), the first overhead gas channel, the condensing tank (15), the fourth LNG channel and the fifth LNG channel are sequentially communicated.
2. The apparatus for recovering c2+ using LNG cold energy according to claim 1, wherein a first bottom heat exchanger (24) is provided at the bottom of the second demethanizer (21), the first bottom heat exchanger (24) comprising a first heat exchanger channel and a second heat exchanger channel; the inlet and the outlet of the first heat exchanger channel are respectively communicated with a discharge port and a feed port at the lower end of the second demethanizer (21); the inlet of the second heat exchanger channel is used for receiving natural gas, and the outlet of the second heat exchanger channel is communicated with the feed inlet of the second demethanizer (21).
3. The apparatus for recovering c2+ using LNG cold energy according to claim 2, wherein the fourth cold box (25) comprises a natural gas channel and a third overhead gas channel, the inlet of the natural gas channel being connected to the outlet of the second heat exchanger channel, the outlet of the natural gas channel being connected to the feed inlet of the second demethanizer (21); and the inlet of the third tower top gas channel is communicated with a discharge port at the top of the second demethanizer (21).
4. The device for recycling c2+ using LNG cold energy according to claim 1, further comprising a middle circulation structure (3), the middle circulation structure (3) comprising a middle circulation pump (31) and a middle circulation heat exchanger (32);
The input end of the middle section circulating pump (31) is connected to a discharge port in the middle of the first demethanizer (14), the output end of the middle section circulating pump (31) is provided with a first branch and a second branch, the output ends of the first branch and the second branch are respectively connected to two feed inlets in the middle of the first demethanizer (14), and the second branch is provided with the middle section circulating heat exchanger (32); and/or, the input end of the middle section circulating pump (31) is connected to the discharge port in the middle part of the second demethanizer (21), the output end of the middle section circulating pump (31) is provided with a first branch and a second branch, the output ends of the first branch and the second branch are respectively connected to two feed inlets in the middle part of the second demethanizer (21), and the second branch is provided with the middle section circulating heat exchanger (32).
5. A method for recovering c2+ using LNG cold energy, applied to the apparatus according to any one of claims 1 to 4, comprising the steps of:
S1: the raw material LNG (41) in the storage tank is boosted by a feed pump, and is subjected to heat exchange in the first cold box (11) and the second cold box (12) in sequence, and enters the first flash tank (13) after heat exchange;
the raw natural gas (42) enters a second demethanizer (21);
S2: the flash gas generated at the top of the first flash tank (13) returns to the first cold box (11) for heat exchange and liquefaction, and enters the second flash tank (16) after being liquefied;
detecting the concentration of C2+ in the liquid phase discharged from the bottom of the second flash tank (16), and if the concentration exceeds a set value, entering the first demethanizer (14);
S3: LNG flash liquid (43) generated at the bottom of the first flash tank (13) enters the third cold box (22) for heat exchange, and enters the first demethanizer (14) after heat exchange;
Detecting the concentration of C2+ in the tower top gas generated by the second demethanizer (21), and if the concentration exceeds a set value, entering a third cold box (22) for heat exchange; after heat exchange, the mixture is returned to the second demethanizer (21) through a reflux tank (23);
s4, fractionating the flash gas partially liquefied in the step 2 and the LNG flash liquid (43) in the step 3 by using a first demethanizer (14) to obtain a C2+ product (44);
the second demethanizer (21) fractionates the raw natural gas (42) and the top gas refluxed in step 3 to obtain a C2+ product (44) and a C2+ natural gas removal product (45);
S5: the overhead gas produced by the first demethanizer (14) is returned to the second cold box (12) for heat exchange and liquefaction.
6. The method for recovering c2+ using LNG cold energy according to claim 5, wherein in step 1, the raw natural gas (42) at normal temperature and the bottom components of the second demethanizer (21) are subjected to heat exchange by the first bottom heat exchanger (24); the raw natural gas (42) after heat exchange enters a fourth cold box (25) to be cooled to be partially liquefied, and then enters a second demethanizer (21).
7. The method for recovering c2+ using LNG cold energy according to claim 6, wherein in step 2, if the concentration of c2+ in the liquid phase discharged from the bottom of the second flash tank (16) is lower than a set value, the liquid phase is introduced into the condensing tank (15); the liquefied top gas discharged from the second cooling box (12) in the step 5 enters a condensing tank (15); the liquid phase discharged from the condensing tank (15) is sequentially discharged after heat exchange in the third cold box (22) and the fourth cold box (25), and a C2-removed LNG product (46) is obtained.
8. The method for recycling c2+ using LNG cold energy according to claim 7, wherein in step 3, if the concentration of c2+ in the overhead gas generated in the second demethanizer (21) is lower than a set value, the overhead gas is sent to the fourth cold box (25) to exchange heat and then is discharged, and a decarbonized natural gas product (45) is obtained.
9. The method for recycling c2+ using LNG cold energy according to any one of claims 5 to 8, wherein the middle section component of the first demethanizer (14) is discharged from a discharge port, and after being pressurized by a middle section circulation pump (31), a part of the component is returned to the first demethanizer (14) for circulation reaction, and the other part of the component is returned to the first demethanizer (14) for circulation reaction after being heat-exchanged with the ethylene glycol aqueous solution (33) in a middle section circulation heat exchanger (32); and/or the number of the groups of groups,
And the middle section component of the second demethanizer (21) is discharged from a discharge port, is pressurized by a middle section circulating pump (31), and part of the components returns to the second demethanizer (21) for circulating reaction, and the other part of components and the glycol water solution (33) exchange heat in a middle section circulating heat exchanger (32) and then returns to the second demethanizer (21) for circulating reaction.
CN202210973645.8A 2022-08-15 2022-08-15 Device and method for recycling C2+ by utilizing LNG cold energy Active CN115232657B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210973645.8A CN115232657B (en) 2022-08-15 2022-08-15 Device and method for recycling C2+ by utilizing LNG cold energy

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210973645.8A CN115232657B (en) 2022-08-15 2022-08-15 Device and method for recycling C2+ by utilizing LNG cold energy

Publications (2)

Publication Number Publication Date
CN115232657A CN115232657A (en) 2022-10-25
CN115232657B true CN115232657B (en) 2024-04-26

Family

ID=83678522

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210973645.8A Active CN115232657B (en) 2022-08-15 2022-08-15 Device and method for recycling C2+ by utilizing LNG cold energy

Country Status (1)

Country Link
CN (1) CN115232657B (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1821352A (en) * 2006-01-20 2006-08-23 华南理工大学 Light hydrocarbon separating method for liquefied natural gas with peak regulating function
CN107940893A (en) * 2017-11-21 2018-04-20 四川金英科技有限责任公司 Using the LNG cold energy stepped utilization methods of cold energy lighter hydrocarbons recovery
CN111684227A (en) * 2017-12-15 2020-09-18 沙特阿拉伯石油公司 Process integration for natural gas condensate recovery
CN112393486A (en) * 2020-11-06 2021-02-23 中国海洋石油集团有限公司 Method for utilizing cold energy of liquefied natural gas

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1821352A (en) * 2006-01-20 2006-08-23 华南理工大学 Light hydrocarbon separating method for liquefied natural gas with peak regulating function
CN107940893A (en) * 2017-11-21 2018-04-20 四川金英科技有限责任公司 Using the LNG cold energy stepped utilization methods of cold energy lighter hydrocarbons recovery
CN111684227A (en) * 2017-12-15 2020-09-18 沙特阿拉伯石油公司 Process integration for natural gas condensate recovery
CN112393486A (en) * 2020-11-06 2021-02-23 中国海洋石油集团有限公司 Method for utilizing cold energy of liquefied natural gas

Also Published As

Publication number Publication date
CN115232657A (en) 2022-10-25

Similar Documents

Publication Publication Date Title
CN107001180B (en) Method and apparatus for producing hydrocarbons
US4695349A (en) Process and apparatus for distillation and/or stripping
CN111108178A (en) Conversion of natural gas condensate fractionation plant waste heat to cooling capacity using a kalina cycle
CN108592519A (en) Helium and liquefied apparatus and method are put forward from natural gas
RU97103016A (en) METHOD AND COOLING SYSTEM IN THE CLOSED CIRCUIT OF THE MIXED REFRIGERANT
JPS58193080A (en) Method and device for recovering argon from air separating plant only for oxygen
EP3719427A1 (en) Cryogenic distillation method and apparatus for producing pressurized air by means of expander booster in linkage with nitrogen expander for braking
CN100560478C (en) To contain tritium light-water or heavy water is the production method that raw material extracts pure tritium
KR100573528B1 (en) Process for the production of carbon monoxide
CN107328166A (en) One kind uses bicirculating CO cryogenic separations system and its separation method
CN110256202A (en) A kind of refining crude methanol process of four towers quadruple effect
EP3386609B1 (en) Process and system for the purification of a gas
RU2182035C1 (en) Plant for preparation and processing of hydrocarbon materials of gas-condensate pools
CN115232657B (en) Device and method for recycling C2+ by utilizing LNG cold energy
CN1952569A (en) Process and equipment for liquefying air-containing coal-bed gas
US20230322652A1 (en) Ethanol production via distillation and dehydration
CN208751134U (en) A kind of device of the cryogenic separation CO gas of nitrogen cycle refrigeration
CN105910387B (en) The process unit and method of cold are reclaimed in a kind of LNG from coke-stove gas
CN107641535A (en) Film deep cooling integrated separation purifies the device and method of multiple gases
CN106885449B (en) Utilize the air-separating technology of cold energy of liquefied natural gas
CN208042611U (en) Helium and liquefied device are carried from natural gas
CN107473223A (en) A kind of CO cryogenic separation system and method using nitrogen cycle
CN104964515B (en) Synthetic ammonia tailgas comprehensive utilization process and device
CN108036584A (en) The method and apparatus of High Purity Nitrogen, oxygen and liquid oxygen is produced from air by cryogenic rectification
JPS61254177A (en) Extraction of ethanol from ethanol-containing liquid

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant