CN103398545B - System for producing liquefied natural gas from raw gas by means of multi-stage pressure throttling - Google Patents
System for producing liquefied natural gas from raw gas by means of multi-stage pressure throttling Download PDFInfo
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- 239000007789 gas Substances 0.000 title claims abstract description 73
- 239000003949 liquefied natural gas Substances 0.000 title abstract description 33
- 230000006835 compression Effects 0.000 claims abstract description 70
- 238000007906 compression Methods 0.000 claims abstract description 70
- 238000001816 cooling Methods 0.000 claims abstract description 53
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 64
- 239000003345 natural gas Substances 0.000 claims description 26
- 239000012530 fluid Substances 0.000 claims description 24
- 238000009826 distribution Methods 0.000 claims description 6
- 238000003860 storage Methods 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 5
- 239000003245 coal Substances 0.000 claims description 4
- 230000008676 import Effects 0.000 claims description 4
- 238000005057 refrigeration Methods 0.000 abstract description 11
- 238000005516 engineering process Methods 0.000 abstract description 9
- 230000002427 irreversible effect Effects 0.000 abstract description 4
- 230000000694 effects Effects 0.000 abstract 1
- 238000011069 regeneration method Methods 0.000 abstract 1
- 238000004519 manufacturing process Methods 0.000 description 7
- 238000000034 method Methods 0.000 description 6
- 239000003507 refrigerant Substances 0.000 description 6
- 239000000446 fuel Substances 0.000 description 4
- 239000012535 impurity Substances 0.000 description 3
- 230000035800 maturation Effects 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000002803 fossil fuel Substances 0.000 description 1
- 239000003317 industrial substance Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
Classifications
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- 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
- F25J1/0002—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the fluid to be liquefied
- F25J1/0022—Hydrocarbons, e.g. natural gas
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- 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
- F25J1/003—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production
- F25J1/0032—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration"
- F25J1/004—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration" by flash gas recovery
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- 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
- F25J1/003—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production
- F25J1/0032—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration"
- F25J1/0045—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the kind of cold generation within the liquefaction unit for compensating heat leaks and liquid production using the feed stream itself or separated fractions from it, i.e. "internal refrigeration" by vaporising a liquid return stream
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- 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
- F25J1/006—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures characterised by the refrigerant fluid used
- F25J1/0097—Others, e.g. F-, Cl-, HF-, HClF-, HCl-hydrocarbons etc. or mixtures thereof
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- 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
- F25J1/0203—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 using a single-component refrigerant [SCR] fluid in a closed vapor compression cycle
- F25J1/0208—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 using a single-component refrigerant [SCR] fluid in a closed vapor compression cycle in combination with an internal quasi-closed refrigeration loop, e.g. with deep flash recycle loop
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- 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
- F25J1/0203—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 using a single-component refrigerant [SCR] fluid in a closed vapor compression cycle
- F25J1/0208—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 using a single-component refrigerant [SCR] fluid in a closed vapor compression cycle in combination with an internal quasi-closed refrigeration loop, e.g. with deep flash recycle loop
- F25J1/0209—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 using a single-component refrigerant [SCR] fluid in a closed vapor compression cycle in combination with an internal quasi-closed refrigeration loop, e.g. with deep flash recycle loop as at least a three level refrigeration cascade
- F25J1/021—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 using a single-component refrigerant [SCR] fluid in a closed vapor compression cycle in combination with an internal quasi-closed refrigeration loop, e.g. with deep flash recycle loop as at least a three level refrigeration cascade using a deep flash recycle loop
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- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Thermal Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Separation By Low-Temperature Treatments (AREA)
Abstract
The invention discloses a system for producing LNG (liquefied natural gas) from raw gas by means of multi-stage compression and throttling. The system comprises n-stage compression cooling units, a precooling heat exchanger, n main cooling heat exchangers, n throttling valves, n distributing valves and a flash tank which are serially connected with one another by pipelines; the n is a positive integer ranging from 2 to 4; the raw gas is cooled by means of multi-stage compression, and then sequentially flows through the n main cooling heat exchangers, a part of gas flow is separated from the raw gas after the raw gas flows through each main cooling heat exchanger, the parts of the gas flow are throttled and then backwardly flow through the corresponding front main cooling heat exchangers and the precooling heat exchanger, cold flow is recycled, and the parts of the gas flow finally flow back to corresponding pressure inlets of multi-stage compressor units; the raw gas is completely throttled and flows into the flash tank after flowing through the last main cooling heat exchanger, a part of the liquefied natural gas which flows out of the bottom of the flash tank is an LNG product, and other parts of the liquefied natural gas and flash steam flow backwardly via the various heat exchangers, and flow back to an inlet of a first-stage compressor after cold flow is recycled. The system has the advantages that a conventional refrigeration technology for precooling is mature and reliable, partial low-temperature cold flow is generated by the liquefied natural gas by means of self-throttling, and irreversible loss in a compression heat regeneration procedure can be reduced owing to a multi-stage pressure throttling effect.
Description
Technical field
The present invention relates to gas liquefaction field, the system of the production liquefied natural gas of particularly a kind of unstripped gas multi-stage compression throttling.
Background technology
The advantages such as natural gas is a kind of high-quality, efficiently clean energy resource and industrial chemicals, has calorific value high, and combustion product environmental pollution is few, are considered to high-quality clean fuel.Along with the development of World Economics, the environmental problem that the use of the fossil fuel such as coal and oil brings is day by day serious, and natural gas, as the consumption figure sharp increase of clear energy sources, is widely used in the every field of the development of the national economy.
Because the place of production of natural gas is not often in area that is industrial or population concentration, its place of production makes it transport with the situation be separated of area of consumption and stores the problem being called and must solving.As a kind of important application form of natural gas, the specific volume of liquefied natural gas (LNG) is only 1/625 of methane under standard state, in conveying with store and have clear superiority; Because it has the unrivaled advantage of other fuel in transport, utilization and environmental protection etc., LNG has become the new industry of a fast development.LNG technology except with solving except natural gas transportation, storage problem, on peak adjusting device when being also usually used in natural gas motorcar.Natural gas is as the fuel in city domestic gas or power plant, and the fluctuation of inevitable oil return requirement, this just requires that supplier has Peak Load Adjustment.In addition, liquefied natural gas also can be used as the fuel of the transport facility such as automobile, boats and ships.
The liquefaction flow path of natural gas can be divided into liquefaction flow path and natural gas self liquefaction flow path of band cold-producing medium according to the difference of refrigeration working medium.Liquefaction flow path wherein with cold-producing medium, cold is produced by refrigerant circulation, unstripped gas is cooled to condensing temperature, as Cascade, mix refrigerant liquefaction flow path, nitrogen expansion liquefaction flow path etc., in this kind of flow process, natural gas itself is not as refrigeration working medium, only absorption refrigeration cycle produce cold and reach liquefaction.And in natural gas self liquefaction flow path, raw natural gas itself is also refrigeration working medium, produces cold by the expansion of high pressure feed self and make natural gas liquefaction.All utilize decompressor as the pressure drop parts of high-pressure natural gas in current existing natural gas self liquefaction technology, two parts are divided into after patent mesohigh unstripped gas as: CN1264848A obtains precooling in precool heat exchanger device, part throttling, another part is expanded to same low pressure, liquid phase part after throttling is LNG product, gas phase portion gets back to feed gas compressor entrance jointly with the part after expansion, and this flow process only has heat transfer temperature difference in its low-temperature zone heat exchanger of a low-pressure stage larger.The liquifying method of the patent of CN1082183 uses unstripped gas multi-stage compression, and high pressure feed gets back to multi-stage compression unit relevant pressure entrance after merotomizing and being expanded to multiple intermediate pressure respectively.This kind of technology is at low-temperature space all containing decompressor, and the investment of equipment complexity is high, and maintaining is inconvenient.
In addition, multi-stage compression multi-level throttle Refrigeration Technique also has application in closed-loop refrigeration circulation, and the two stages of compression two-stage throttling refrigeration as general cold field circulates, and main purpose solves the problem that when realizing low temperature, compressor pressure ratio is excessive.The patent of the present inventor's application number 201210526647.9 adopts multi-stage compression multi-level throttle to the cooling flow of intermediate pressure, and flow process adopts closed cycle and refrigeration working medium is mix refrigerant.
Compared with prior art, system pre-cooling section of the present invention adopts conventional refrigerant means, and unstripped gas compression adopts conventional natural gas compressor, the equal mature and reliable of technology; Low temperature part cold is produced by high-pressure natural gas self throttling, and structure is simple, movement-less part, and reliability is high; Multistage pressure throttling reduces the irreversible loss of compression and heat recovery process, and efficiency is high.
Summary of the invention
The object of the present invention is to provide a kind of unstripped gas to produce the system of liquefaction LNG through multi-stage compression throttling, this system pre-cooling section adopts conventional refrigerant means, and technology maturation is reliable; Low temperature part cold is produced by high-pressure natural gas self throttling, and can use ripe natural gas compressor, reliability is high; System multi-stage compression and throttling reduce irreversible loss, can reach higher efficiency.
Technical solution of the present invention is as follows:
Unstripped gas provided by the invention produces the system of liquefied natural gas (LNG) through multi-stage compression throttling, it compresses cooling unit, precool heat exchanger device PHX, n main cold heat exchanger (HXn by the n level be connected in series by pipeline, HXn-1 ..., HX1), a n choke valve (Vn, Vn-1,, V1), n distributing valve (Tn, Tn-1,, T1) and a flash tank FT form; Described n is 2 ~ 4 positive integers; First order compression cooling unit in described n level compression cooling unit is made up of the first compressor C1 and the first aftercooler AC1, second level compression cooling unit is made up of the second compressor C2 and the second aftercooler AC2, by that analogy, n-th grade of compression cooling unit is made up of the n-th compressor Cn and the n-th aftercooler ACn;
The individual main cold heat exchanger of described precool heat exchanger device PHX, n (HXn, HXn-1 ..., HX1) and flash tank FT be serially connected with the exit of the n-th aftercooler ACn of described n-th grade of compression cooling unit successively by pipeline;
Through the compression cooled high pressure feedstock air-flow M0 of n level compression cooling unit, first precool heat exchanger device PHX is flow through, then the n-th main cold heat exchanger HXn is entered, and flowed out by the n-th main cold heat exchanger HXn, after through being loaded on the distribution of the n-th distributing valve Tn in the n-th main cold heat exchanger HXn exit, some fluid Mn is separated, this fluid Mn oppositely flows through the n-th main cold heat exchanger HXn and precool heat exchanger device PHX successively after being loaded on the n-th choke valve Vn choke pressure drop on this fluid Mn pipeline, is finally back to the entrance of the n-th compressor Cn; Another fluid streams M0n that n-th distributing valve Tn flows out enters the (n-1)th main cold heat exchanger HXn-1, and flowed out by the (n-1)th main cold heat exchanger HXn-1, after through being loaded on the distribution of the (n-1)th distributing valve Tn-1 in the (n-1)th main cold heat exchanger HXn-1 exit, some fluid Mn-1 is separated, this fluid Mn-1 oppositely flows through the (n-1)th main cold heat exchanger HXn-1, the n-th main cold heat exchanger HXn and precool heat exchanger device PHX successively after being loaded on the (n-1)th choke valve Vn-1 choke pressure drop on this fluid Mn-1 pipeline, finally gets back to the entrance of the (n-1)th stage compressor Cn-1; The like until high pressure feedstock air-flow flow into the 1st main cold heat exchanger HX1; The high pressure feed flowing out the 1st main cold heat exchanger HX1 enters flash tank FT after flowing through Section 1 stream valve V1 choke pressure drop being loaded on the 1st main cold heat exchanger HX1 exit, and flows out by bottom flash tank FT, and the liquid of this outflow is liquefaction unstripped gas; After this liquefaction unstripped gas is loaded on the first distributing valve T1 distribution at flash tank FT bottom end outlet place, major part liquefaction unstripped gas enters storage tank collection as LNG product, another part liquefaction unstripped gas M1 and flash tank FT top gas out flow counterflow through whole n main cold heat exchanger (HX1 simultaneously,, HXn) and precool heat exchanger device PHX reclaim the entrance flowing back into the 1st compressor C1 after cold.
The import of described unstripped gas is according to the import or export place not being located on the compressor of one stage of compression cooling unit arbitrarily in n level compression cooling unit of raw gas pressure.
Described natural gas is through the natural gas being rich in methane of purified treatment, coal bed gas and shale gas.
Described precool heat exchanger device PHX also comprises one forecooling fluid PM; Precool heat exchanger device PHX outlet temperature is cooled to-30 DEG C ~-60 DEG C by this forecooling fluid PM.The pressure of the described compression cooled high pressure feedstock air-flow M0 through n level compression cooling unit is 6.0 ~ 8.0MPa.Described precool heat exchanger device PHX and n main cold heat exchanger is multichannel recuperative heat exchanger.
The system that unstripped gas provided by the invention produces liquefaction LNG through multi-stage compression throttling has the following advantages:
Unstripped gas of the present invention produces the system of liquefaction LNG through multi-stage compression throttling, and its feed gas compressor can adopt ripe natural gas compressor, cheap and easy to get, and maintenance is convenient; Chilldown system produces and uses conventional refrigerant means, technology maturation, and reliability is high; Low temperature part cold is produced by high-pressure natural gas self throttling, and structure is simple, movement-less part, and reliability is high; Multiple pressure stages that can make full use of compound compressor provides improve the heat equivalent matching problem of cold fluid and hot fluid in Recuperative heat exchanger, reduce high/low temperature fluid temperature difference in Recuperative heat exchanger, reduce heat recovery process irreversible loss, improve system effectiveness.
Accompanying drawing explanation
Fig. 1 is structure of the present invention (flow process) schematic diagram;
Fig. 2 is the system of the unstripped gas throttling production liquefied natural gas that embodiments of the invention 1 adopt 3 grades to compress;
Fig. 3 is the system of the unstripped gas throttling production liquefied natural gas that embodiments of the invention 2 adopt 2 grades to compress;
Fig. 4 is the system of the unstripped gas throttling production liquefied natural gas that embodiments of the invention 3 adopt 4 grades to compress.
Detailed description of the invention
The present invention is further described below in conjunction with drawings and Examples:
Embodiment 1
As shown in Figure 2, the present embodiment Raw gas is natural gas, and main component is methane, and after purified treatment, its impurity content meets general liquefaction index; The pressure that unstripped gas enters liquefaction system is 3.1MPa, and temperature is 20 DEG C.
N=3 in the present embodiment, namely n level compression cooling unit is 3 grades of compression cooling units (first order compression cooling units be made up of first order compressor C1 and first order aftercooler CA1, the second level compression cooling unit be made up of high stage compressor C2 and second level aftercooler CA2, and the third level compression cooling unit be made up of third level compressor C3 and third level aftercooler CA3;
Pressure through the compression of 3 grades of compression cooling units and cooled flow of feed gas M0 is 6MPa, and temperature is 20 DEG C; Flow of feed gas M0 flows through precool heat exchanger device PHX afterwards, in precool heat exchanger device PHX, be cooled to-60 DEG C, then enters the 3rd main cold heat exchanger; Flow of feed gas M0 is cooled to-90 DEG C in the 3rd main cold heat exchanger HX3, then the 3rd tributary M3 and M03 is separated into through the 3rd distributing valve T3, wherein the 3rd tributary M3 is after the 3rd choke valve V3 throttling to 3.1MPa, and the entrance entering the 3rd compressor C3 after flowing counterflow through the 3rd main cold heat exchanger HX3 and precool heat exchanger device PHX circulates again; And M03 enters the second main cold heat exchanger HX2, be cooled to-115 DEG C wherein, then the second tributary M2 and M02 is separated into through the second distributing valve T2, wherein the second tributary M2 is after second throttle V2 throttling to 1.44MPa, and the entrance entering the second compressor C2 after oppositely flowing through the second main cold heat exchanger HX2, the 3rd main cold heat exchanger HX3 and precool heat exchanger device PHX successively circulates again; And M02 enters the first main cold heat exchanger HX1, be cooled to-140 DEG C wherein, then after first throttle valve V1 throttling to 0.4MPa, flash tank FT is entered, be separated into the first tributary M1 and LNG by liquid out bottom flash tank through the first distributing valve T1, the entrance that wherein the first tributary M1 enters the first compressor C1 after together oppositely flowing through the first main cold heat exchanger HX1, the second main cold heat exchanger HX2, the 3rd main cold heat exchanger HX3 and precool heat exchanger device PHX successively with flash tank FT top gaseous fluid out circulates again; And LNG enters storage tank (follow-up system) as liquiefied product.
The system of the present embodiment 1 adopts Pre-cooling Mode to be conventional folding type cooling system, high-temperature level refrigeration working medium is R22, cryogenic temperature is-20 DEG C, and low-temperature level precooling working medium is that R23 cryogenic temperature is-65 DEG C, chilldown system by precool heat exchanger device PHX for main cooling system provides precooling cold.
In the present embodiment 1, the flow of the flow of the 3rd branch road M3 to be the flow of the 71% of M0, second branch road M2 be the 10% of M0, first branch road M1 is 4% of M0, and LNG stream amount is 15% of M0.Unstripped gas liquefaction is 0.30kWh/Nm than power consumption
3.
Precool heat exchanger device PHX in the present embodiment 1 adopts conventional two-stage folding type cooling system, and unstripped gas is chilled to-60 DEG C in advance, and compressor can adopt conventional gas compressor, technology maturation, easily implements, and adopts reducing pressure by regulating flow, movement-less part in ice chest, system reliability is high.
Embodiment 2
The present embodiment 2 Raw gas is natural gas, and main component is methane, and after purified treatment, its impurity content meets general liquefaction index; The pressure that unstripped gas enters liquefaction system is, 0.44MPa, and temperature is 20 DEG C.
As Fig. 3, n=2 in the present embodiment, namely n level compression cooling unit is 2 grades of compression cooling units (first order compression cooling unit be made up of first order compressor C1 and first order aftercooler CA1, the second level be made up of high stage compressor C2 and second level aftercooler CA2 compression cooling units;
Identical with embodiment 1 of the Pre-cooling Mode that the system of the present embodiment 2 adopts and precooling temperature.
Pressure through the compression of 2 grades of compression cooling units and cooled flow of feed gas M0 is 6MPa, and temperature is 20 DEG C; Flow of feed gas M0 flows through precool heat exchanger device PHX afterwards, in precool heat exchanger device PHX, be cooled to-60 DEG C, then enters the second main cold heat exchanger; Flow of feed gas M0 is cooled to-110 DEG C in the second main cold heat exchanger HX3, then the second tributary M2 and M02 is separated into through the second distributing valve T2, wherein the 3rd tributary M2 is after the 3rd choke valve V2 throttling to 1.2MPa, and the entrance entering the second compressor C2 after flowing counterflow through the second main cold heat exchanger HX2 and precool heat exchanger device PHX circulates again; And M02 enters the first main cold heat exchanger HX1, be cooled to-140 DEG C wherein, then after first throttle valve V1 throttling to 0.44MPa, flash tank FT is entered, be separated into the first tributary M1 and LNG by liquid out bottom flash tank through the first distributing valve T1, the entrance that wherein the first tributary M1 enters the first compressor C1 after together oppositely flowing through the first main cold heat exchanger HX1, the second main cold heat exchanger HX2 and precool heat exchanger device PHX successively with flash tank FT top gaseous fluid out circulates again; And LNG enters storage tank (follow-up system) as liquiefied product.
1st compressor C1 inlet pressure 0.44MPa in the present embodiment 2, the 2nd compressor C2 inlet pressure 1.6MPa, the 2nd compressor C3 outlet pressure 6.0MPa.The flow of the 2nd branch road M2 is the flow of the 65% of M0,1st branch road M1 is 14% of M0, and LNG stream amount is 20.16% of M0.Unstripped gas liquefaction is 0.47kWh/Nm than power consumption
3.
System in the present embodiment 2 is compared with embodiment 1, and few one stage of compression and throttling, system equipment is less, and more simply, but due to the minimizing of throttling progression, in Recuperative heat exchanger, heat transfer temperature difference is larger, and efficiency is a little less than embodiment 1.Simultaneously because imported raw material atmospheric pressure is low, for unstripped gas supercharging too increases part power consumption.
Embodiment 3
The present embodiment 3 Raw gas is coal bed gas, and main component is methane, and after purified treatment, its impurity content meets general liquefaction index; The pressure that unstripped gas enters liquefaction system is 4.0MPa, and temperature is 20 DEG C.
As Fig. 4, n=4 in the present embodiment, namely n level compression cooling unit is 4 grades of compression cooling units (first order compression cooling units be made up of first order compressor C1 and first order aftercooler CA1, the second level compression cooling unit be made up of high stage compressor C2 and second level aftercooler CA2, the third level compression cooling unit be made up of third level compressor C3 and third level aftercooler CA3, and the fourth stage compression cooling unit be made up of fourth stage compressor C4 and fourth stage aftercooler CA4;
In the present embodiment 3, the Pre-cooling Mode of system selects R22 refrigeration two-stage compression cycle, and precooling temperature is-30 DEG C.
Pressure through the compression of 4 grades of compression cooling units and cooled flow of feed gas M0 is 8MPa, and temperature is 20 DEG C; Flow of feed gas M0 flows through precool heat exchanger device PHX afterwards, in precool heat exchanger device PHX, be cooled to-30 DEG C, then enters the 4th main cold heat exchanger; Flow of feed gas M0 is cooled to-70 DEG C in the 4th main cold heat exchanger HX4, then the 4th tributary M4 and M04 is separated into through the 4th distributing valve T4, wherein the 4th tributary M4 is after the 4th choke valve V4 throttling to 4MPa, and the entrance entering the 4th compressor C4 after flowing counterflow through the 4th main cold heat exchanger HX4 and precool heat exchanger device PHX circulates again; And M04 enters the 3rd main cold heat exchanger HX3, be cooled to-95 DEG C wherein, then the 3rd tributary M3 and M03 is separated into through the 3rd distributing valve T3, wherein the 3rd tributary M3 is after the 3rd choke valve V3 throttling to 2MPa, flow counterflow through the 3rd main cold heat exchanger HX3, the entrance entering the 3rd compressor C3 after the 4th main cold heat exchanger HX4 and precool heat exchanger device PHX circulates again; And M03 enters the second main cold heat exchanger HX2, be cooled to-115 DEG C wherein, then the second tributary M2 and M02 is separated into through the second distributing valve T2, wherein the second tributary M2 is after second throttle V2 throttling to 1MPa, oppositely flow through the second main cold heat exchanger HX2, the 3rd main cold heat exchanger HX3 successively, the entrance entering the second compressor C2 after the 4th main cold heat exchanger HX4 and precool heat exchanger device PHX circulates again; And M02 enters the first main cold heat exchanger HX1, be cooled to-140 DEG C wherein, then after first throttle valve V1 throttling to 0.4MPa, flash tank FT is entered, the first tributary M1 and LNG is separated into through the first distributing valve T1 by liquid out bottom flash tank, wherein the first tributary M1 together oppositely flows through the first main cold heat exchanger HX1, the second main cold heat exchanger HX2, the 3rd main cold heat exchanger HX3 successively with flash tank FT top gaseous fluid out, and the entrance entering the first compressor C1 after the 4th main cold heat exchanger HX4 and precool heat exchanger device PHX circulates again; And LNG enters storage tank (follow-up system) as liquiefied product.
1st compressor C1 inlet pressure 0.4MPa in the present embodiment 3, C1 outlet pressure 1.0MPa, 2nd compressor C2 outlet pressure 2.0MPa, 3rd compressor C3 outlet pressure 4.0MPa, the 4th compressor C4 outlet pressure 8.0MPa, the flow of the 4th branch road M4 is 61.44% of M0, the flow of the 3rd branch road M3 is 14% of M0, the flow of the 2nd branch road M2 is the flow of the 4.5% of M0,1st branch road M1 is 3.5% of M0, and product LNG stream amount is 16% of M0.Unstripped gas liquefaction is 0.26kWh/Nm than power consumption
3.
System in the present embodiment 3 is compared with embodiment 1, and many one stage of compression and throttling, system equipment is less, and because throttling progression increases, in Recuperative heat exchanger, heat transfer temperature difference is less, and efficiency is higher than embodiment 1.
Claims (6)
1. a unstripped gas produces the system of liquefaction LNG through multi-stage compression throttling, it compresses cooling unit, precool heat exchanger device (PHX), a n main cold heat exchanger (HXn by the n level that is connected in series by pipeline, HXn-1 ..., HX1), a n choke valve (Vn, Vn-1,, V1), n distributing valve (Tn, Tn-1,, T1) and flash tank (FT) composition; Described n is 2 ~ 4 positive integers; First order compression cooling unit in described n level compression cooling unit is made up of the first compressor (C1) and the first aftercooler (AC1), second level compression cooling unit is made up of the second compressor (C2) and the second aftercooler (AC2), by that analogy, n-th grade of compression cooling unit is made up of the n-th compressor (Cn) and the n-th aftercooler (Can);
Described precool heat exchanger device (PHX), n main cold heat exchanger (HXn, HXn-1,, HX1) and flash tank (FT) be serially connected with the exit of the n-th aftercooler (Can) of described n-th grade of compression cooling unit successively by pipeline;
Through the cooled high pressure feedstock air-flow (M0) of compression of n level compression cooling unit, first precool heat exchanger device (PHX) is flow through, then the n-th main cold heat exchanger (HXn) is entered, and flowed out by the n-th main cold heat exchanger (HXn), after through being loaded on the distribution of n-th distributing valve (Tn) in the n-th main cold heat exchanger (HXn) exit, some fluid (Mn) is separated, this fluid (Mn) oppositely flows through the n-th main cold heat exchanger (HXn) and precool heat exchanger device (PHX) successively after being loaded on the n-th choke valve (Vn) choke pressure drop on this fluid (Mn) pipeline, finally be back to the entrance of the n-th compressor (Cn), another fluid streams (M0n) that n-th distributing valve (Tn) flows out enters the (n-1)th main cold heat exchanger (HXn-1), and flowed out by the (n-1)th main cold heat exchanger (HXn-1), after through being loaded on the distribution of (n-1)th distributing valve (Tn-1) in the (n-1)th main cold heat exchanger (HXn-1) exit, some fluid (Mn-1) is separated, this fluid (Mn-1) oppositely flows through the (n-1)th main cold heat exchanger (HXn-1) successively after being loaded on the (n-1)th choke valve (Vn-1) choke pressure drop on this fluid (Mn-1) pipeline, n-th main cold heat exchanger (HXn) and precool heat exchanger device (PHX), finally get back to the entrance of the (n-1)th stage compressor (Cn-1), the like, until high pressure feedstock air-flow flows into the 1st main cold heat exchanger (HX1), the high pressure feed flowing out the 1st main cold heat exchanger (HX1) enters flash tank (FT) after flowing through Section 1 stream valve (V1) choke pressure drop being loaded on the 1st main cold heat exchanger (HX1) exit, and flow out by bottom flash tank FT, the liquid of this outflow is liquefaction unstripped gas, after this liquefaction unstripped gas is loaded on the first distributing valve (T1) distribution at flash tank (FT) bottom end outlet place, major part liquefaction unstripped gas enters storage tank collection as LNG product, another part liquefaction unstripped gas (M1) and flash tank (FT) top gas out flow counterflow through whole n main cold heat exchanger (HX1 simultaneously,, HXn) and precool heat exchanger device (PHX) reclaim cold after flow back into the entrance of the first compressor (C1).
2. produce the system of liquefaction LNG by unstripped gas according to claim 1 through multi-stage compression throttling, it is characterized in that, the import of described unstripped gas is arranged in the import or export place of the compressor of any one stage of compression cooling unit of n level compression cooling unit.
3. produce the system of liquefaction LNG by unstripped gas according to claim 1 through multi-stage compression throttling, it is characterized in that, described unstripped gas is through the natural gas being rich in methane of purified treatment, coal bed gas or shale gas.
4. produce the system of liquefaction LNG through multi-stage compression throttling by unstripped gas according to claim 1, it is characterized in that, described precool heat exchanger device (PHX) also comprises one forecooling fluid (PM); Precool heat exchanger device (PHX) outlet temperature is cooled to-30 DEG C ~-60 DEG C by this forecooling fluid (PM).
5. produce the system of liquefaction LNG by unstripped gas according to claim 1 through multi-stage compression throttling, it is characterized in that, the pressure of the described cooled high pressure feedstock air-flow (M0) of compression through n level compression cooling unit is 6.0 ~ 8.0MPa.
6. produce the system of liquefaction LNG by unstripped gas according to claim 1 through multi-stage compression throttling, it is characterized in that, described precool heat exchanger device (PHX) and n main cold heat exchanger are multichannel recuperative heat exchanger.
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| US20160061516A1 (en) * | 2014-08-29 | 2016-03-03 | Black & Veatch Holding Company | Dual mixed refrigerant system |
| CN106016967B (en) * | 2016-05-30 | 2018-11-09 | 中国科学院理化技术研究所 | A kind of back-heating type mixed working fluid refrigerant gas liquefaction cycle system |
| CN107543368B (en) * | 2017-07-21 | 2019-12-27 | 中国科学院理化技术研究所 | Residual BOG gas recycling system |
| CA3075987A1 (en) * | 2017-09-29 | 2019-04-04 | Exxonmobil Upstream Research Company | Natural gas liquefaction by a high pressure expansion process |
| CN111238163B (en) * | 2020-02-13 | 2021-12-17 | 中国科学院理化技术研究所 | Mixed working medium high-pressure gas liquefaction and supercooling system |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1042407A (en) * | 1988-11-03 | 1990-05-23 | 气体产品与化学公司 | The liquefaction again of natural gas vaporization gas |
| JPH05149676A (en) * | 1991-04-26 | 1993-06-15 | Air Prod And Chem Inc | Method of liquefying nitrogen flow |
| US7069743B2 (en) * | 2002-02-20 | 2006-07-04 | Eric Prim | System and method for recovery of C2+ hydrocarbons contained in liquefied natural gas |
| CN201344705Y (en) * | 2008-11-06 | 2009-11-11 | 天津市华迈燃气技术发展有限公司 | Liquefied natural gas preparation device by utilizing compressed natural gas |
| CN202139209U (en) * | 2011-04-21 | 2012-02-08 | 北京工业大学 | Direct expansion type natural gas liquefaction device |
| CN103017480A (en) * | 2012-12-07 | 2013-04-03 | 中国科学院理化技术研究所 | Liquefaction system for producing LNG (Liquefied Natural Gas) by using pressure energy of pipeline |
-
2013
- 2013-07-29 CN CN201310322788.3A patent/CN103398545B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1042407A (en) * | 1988-11-03 | 1990-05-23 | 气体产品与化学公司 | The liquefaction again of natural gas vaporization gas |
| JPH05149676A (en) * | 1991-04-26 | 1993-06-15 | Air Prod And Chem Inc | Method of liquefying nitrogen flow |
| US7069743B2 (en) * | 2002-02-20 | 2006-07-04 | Eric Prim | System and method for recovery of C2+ hydrocarbons contained in liquefied natural gas |
| CN201344705Y (en) * | 2008-11-06 | 2009-11-11 | 天津市华迈燃气技术发展有限公司 | Liquefied natural gas preparation device by utilizing compressed natural gas |
| CN202139209U (en) * | 2011-04-21 | 2012-02-08 | 北京工业大学 | Direct expansion type natural gas liquefaction device |
| CN103017480A (en) * | 2012-12-07 | 2013-04-03 | 中国科学院理化技术研究所 | Liquefaction system for producing LNG (Liquefied Natural Gas) by using pressure energy of pipeline |
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