CN105823304B - A kind of liquefied method and device of twin-stage swell refrigeration high methane gas - Google Patents
A kind of liquefied method and device of twin-stage swell refrigeration high methane gas Download PDFInfo
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- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 title claims abstract description 310
- 238000005057 refrigeration Methods 0.000 title claims abstract description 62
- 238000000034 method Methods 0.000 title claims abstract description 57
- 239000007788 liquid Substances 0.000 claims abstract description 59
- 238000001816 cooling Methods 0.000 claims abstract description 54
- 238000000926 separation method Methods 0.000 claims abstract description 48
- 229930195733 hydrocarbon Natural products 0.000 claims abstract description 43
- 150000002430 hydrocarbons Chemical class 0.000 claims abstract description 43
- 239000004215 Carbon black (E152) Substances 0.000 claims abstract description 41
- 230000001105 regulatory effect Effects 0.000 claims abstract description 19
- 239000000463 material Substances 0.000 claims description 254
- 239000007791 liquid phase Substances 0.000 claims description 15
- 239000012071 phase Substances 0.000 claims description 14
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 6
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 claims description 6
- AMXOYNBUYSYVKV-UHFFFAOYSA-M lithium bromide Chemical compound [Li+].[Br-] AMXOYNBUYSYVKV-UHFFFAOYSA-M 0.000 claims description 6
- 239000002826 coolant Substances 0.000 claims description 4
- 229910021529 ammonia Inorganic materials 0.000 claims description 3
- 239000001294 propane Substances 0.000 claims description 3
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 claims description 3
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 238000001704 evaporation Methods 0.000 claims description 2
- 239000002994 raw material Substances 0.000 claims description 2
- 239000007789 gas Substances 0.000 abstract description 192
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 abstract description 24
- 239000003949 liquefied natural gas Substances 0.000 abstract description 24
- 230000008569 process Effects 0.000 abstract description 14
- 238000005265 energy consumption Methods 0.000 abstract description 11
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 11
- 230000008901 benefit Effects 0.000 abstract description 9
- 238000004519 manufacturing process Methods 0.000 abstract description 3
- 239000003345 natural gas Substances 0.000 description 13
- 239000000203 mixture Substances 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 4
- 230000006835 compression Effects 0.000 description 4
- 238000007906 compression Methods 0.000 description 4
- 150000001335 aliphatic alkanes Chemical class 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 230000032258 transport Effects 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- JVFDADFMKQKAHW-UHFFFAOYSA-N C.[N] Chemical compound C.[N] JVFDADFMKQKAHW-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000005008 domestic process Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000003507 refrigerant Substances 0.000 description 1
- 238000011160 research Methods 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"
- F25J1/0035—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 gas expansion with extraction of work
- F25J1/0037—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 gas expansion with extraction of work of a 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
- F25J1/003—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
-
- 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
- F25J1/0047—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 an "external" refrigerant stream in a closed vapor compression cycle
- F25J1/005—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 an "external" refrigerant stream in a closed vapor compression cycle by expansion of a gaseous refrigerant stream with extraction of work
-
- 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
- F25J1/008—Hydrocarbons
- F25J1/0082—Methane
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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
- F25J1/0201—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 only internal refrigeration means, i.e. without external refrigeration
- F25J1/0202—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 only internal refrigeration means, i.e. without external refrigeration in a quasi-closed internal refrigeration loop
-
- 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
- F25J2220/00—Processes or apparatus involving steps for the removal of impurities
- F25J2220/60—Separating impurities from natural gas, e.g. mercury, cyclic hydrocarbons
- F25J2220/64—Separating heavy hydrocarbons, e.g. NGL, LPG, C4+ hydrocarbons or heavy condensates in general
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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
- F25J2270/00—Refrigeration techniques used
- F25J2270/04—Internal refrigeration with work-producing gas expansion loop
- F25J2270/06—Internal refrigeration with work-producing gas expansion loop with multiple gas expansion loops
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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
- F25J2270/00—Refrigeration techniques used
- F25J2270/14—External refrigeration with work-producing gas expansion loop
- F25J2270/16—External refrigeration with work-producing gas expansion loop with mutliple gas expansion loops of the same refrigerant
Abstract
The invention discloses a kind of liquefied method and devices of twin-stage swell refrigeration high methane gas, belong to high methane gas separation and liquefaction field, purpose is to solve the production method of existing liquefied natural gas, and there are heavy hydrocarbon separation is difficult, it is cumbersome, equipment investment is higher, methane losses are larger, the higher problem of energy consumption.This method includes high methane gas liquefaction, circularly cooling step, after methane rich unstripped gas is mixed with pre- hot gas, through heat exchanger cooling, reducing pressure by regulating flow, gas-liquid separation, respectively obtain liquefying high methane gas, low-flash gas, liquefying high methane gas is collected as product, and low-flash gas then carries out open loop refrigeration or closed cycle.The advantages that present invention has process simple, and low energy consumption, and flexible operation, equipment investment is low, and methane losses are small, and nitrogen separation works well, and heavy hydrocarbon easily removes.
Description
Technical field
The present invention relates to natural gas field, especially high methane gas separation and liquefaction field, specially a kind of twin-stage expansion
The refrigeration liquefied method and device of high methane gas.
Background technique
The growth of natural gas consumption promotes the rapid development of liquefied natural gas industry.From Shanghai LNG accident in 1999
Since gas source standby station (phase) is constructed and put into operation, by the development of more than ten years, Chinese liquefied natural gas industry has been passed by from main
By external complete set technology and equipment is introduced, to the domestic process that can produce liquefied natural gas (LNG) production device with independent research.
Currently, there are three types of types for the domestic natural gas liquefaction refrigeration process generallyd use: cascade refrigeration technique, expansion system
Cold technique and hybrid refrigeration process.
Wherein, swell refrigeration technique has the following advantages.
(1) compared with cascade refrigeration technique and hybrid refrigeration process, swell refrigeration process flow is very simple, compact,
Cost is slightly lower；It starts fastly, 2 ~ 4 h of hot starting can be obtained product at full capacity, and flexible operation is adaptable, produce load tune
Adjusting range is big, has biggish adaptability to unstripped gas composition variation, is easy to operate and control.
(2) it using the natural gas of gaseous state or nitrogen as circularly cooling agent, thus eliminates as hybrid refrigeration cycle
The trouble that refrigerant is separated and stored in technique, also avoids thus bring safety problem.
Swell refrigeration technique mainly uses nitrogen swell refrigeration, nitrogen-methane blended swell refrigeration, natural gas direct expansion system
Cold three kinds of forms.Wherein, a kind of modification of the nitrogen swell refrigeration as direc expansion refrigeration, adaptable strong, liquefying power
It is high, process is simple, flexible operation, it is easy to operate the advantages that, but energy consumption is higher.Nitrogen-methane blended swell refrigeration is then that nitrogen is swollen
A kind of improvement of swollen refrigeration cycle has many advantages, such as that process is simple, control is easy, the starting time is short, expands and make than pure nitrogen gas
The power consumption of cold saving 10%.
Natural gas direc expansion refrigeration be directly using high-pressure natural gas in expanding machine adiabatic expansion and make natural gas liquid
The method of change takes full advantage of the pressure energy of natural gas itself, and consumption electric energy is seldom, saves equipment investment.Using volume
Gas-bearing expansion turbine that is small, light-weight, high-efficient, running reliably and with long-term, can effectively improve system effectiveness, can be used for grasping
In the peak regulation type device for making frequently and requiring rapid starting/stopping.Currently, this method has developed to the liquefaction system of multiple expansion, and swollen
Swollen refrigeration machine also reaches its maturity, and has the characteristics that long-life, high reliability, low vibration, light-weight, have in terms of natural gas liquefaction
There is good development prospect.Under the requirement that liquefaction tolerance increases increasingly, set possessed by natural gas direc expansion refrigeration itself
The advantages that standby compact, small investment, flexible adjustment, reliable operation, so that it is with greater advantage.
Chinese patent CN 103582792A discloses a kind of method for natural gas liquefaction, but it has the disadvantage that.
(1) in this method, into liquefaction expander temperature of charge at -50 DEG C to -80 DEG C, preferably -60 DEG C to -70 DEG C
In range, temperature is too low, more demanding to expander material, and equipment investment is larger.
(2) in this method, liquid phase material is contained in separator, this requires the power of expanding machine larger；Meanwhile pressure drop compared with
Greatly, energy consumption is higher.
(3) expansion work of expanding machine is lost, and energy consumption is higher.
(4) it is required into the temperature of charge of liquefaction expander with the temperature for going out to precool expander: expander outlet object
The temperature of material is lower than the temperature of entrance material.
(4) in this method, heavy hydrocarbon separation is difficult.
(5) this method pressure drop is big, and methane losses are big, and nitrogen separation effect is bad, and nitrogen content is higher in LNG.
Based on disadvantages mentioned above existing for 103582792 A of CN, develop that a kind of process is simple, low energy consumption, flexible operation, sets
The method easily removed with heavy hydrocarbon that standby investment is low, methane losses are small and nitrogen separation works well, which seems, to be even more important.
For this purpose, the present invention provides a kind of liquefied method and device of twin-stage swell refrigeration high methane gas.
Summary of the invention
Goal of the invention of the invention is: for the production method of existing liquefied natural gas, there are heavy hydrocarbons to separate difficult, behaviour
Make cumbersome, equipment investment is higher, and methane losses are larger, and expansion work damage is lost, and it is swollen to provide a kind of twin-stage for the higher problem of energy consumption
The liquefied method and device of swollen refrigeration high methane gas.The present invention has process simple, and low energy consumption, and flexible operation, equipment investment is low,
The advantages that methane losses are small, and nitrogen separation works well, and heavy hydrocarbon easily removes.Meanwhile in the present invention also there is heavy hydrocarbon easily to remove, liquid
Change that high methane gas nitrogen content is low and the strong advantage of adaptability to raw material, with good application prospect.
To achieve the goals above, the present invention adopts the following technical scheme:
A kind of liquefied method of twin-stage swell refrigeration high methane gas, includes the following steps:
(1) high methane gas liquefies:
The operation of the step 1 is as follows: after methane rich unstripped gas is mixed with the pre- hot gas in part, being cooled to -10 through heat exchanger
It ~ -90 DEG C, enters back into heavy hydrocarbon separator and takes off heavy hydrocarbon, obtain low temperature dry gas, low temperature dry gas after heat exchanger is cooling, drops again through throttling
Pressure, then gas-liquid separation is carried out, liquefying high methane gas, low-flash gas are respectively obtained after separation, liquefying high methane gas is as product
It collects, low-flash gas is pressurized after heat exchanger exchanges heat, into next circulation；
If methane rich unstripped gas is without heavy hydrocarbon, directly cold through heat exchanger after methane rich unstripped gas is mixed with the pre- hot gas in part
But, then after reducing pressure by regulating flow, gas-liquid separation is carried out, liquefying high methane gas, low-flash gas are respectively obtained after separation, liquefaction is the richest in
Alkane gas is collected as product, and low-flash gas is pressurized after heat exchanger exchanges heat, into next circulation；
(2) open loop refrigeration:
The operation of the step 2 is as follows: low-flash gas obtains pre- hot gas after heat exchanger exchanges heat, and pre- hot gas is carried out
Pressurization, is classified as first strand of material, second strand of material and three strands of materials, first strand of material is mixed with high methane gas after pressurization
The high methane gas liquefaction of step 1 is carried out into heat exchanger, second strand of material enters the first expander, the material after expansion into
Return pressurization is mixed with pre- hot gas after entering heat exchanger heat exchange, into next circulation；It is cold that three strands of materials sequentially enters heat exchanger
But, the second expander, the material after expansion enter heat exchanger heat exchange, mix return pressurization after heat exchange with pre- hot gas, enter
Next circulation；
Or low-flash gas is after heat exchanger exchanges heat, and obtains pre- hot gas, then by after pre- hot gas supercharged gas with methane rich unstripped gas
It is thoroughly mixed, is then divided into first strand of material, second strand of material and three strands of materials, first strand of material is directly carried out into heat exchanger
The high methane gas of step 1 liquefies, and second strand of material enters the first expander, after the material after expansion enters heat exchanger heat exchange
Return pressurization is mixed with pre- hot gas, into next circulation；Three strands of materials sequentially enters that heat exchanger is cooling, the second expanding machine is swollen
Swollen, the material after expansion enters heat exchanger heat exchange, return pressurization is mixed after heat exchange with pre- hot gas, into next circulation；
Another replacement method is provided, is included the following steps:
(1) high methane gas liquefies:
The operation of the step 1 is as follows: after methane rich unstripped gas is mixed with the pre- hot gas in part, being cooled to -10 through heat exchanger
It ~ -90 DEG C, enters back into heavy hydrocarbon separator and takes off heavy hydrocarbon, obtain low temperature dry gas, low temperature dry gas after heat exchanger is cooling, drops again through throttling
Pressure, then gas-liquid separation is carried out, liquefying high methane gas, low-flash gas are respectively obtained after separation, liquefying high methane gas is as product
It collects, low-flash gas is pressurized after heat exchanger exchanges heat, into next circulation；
If methane rich unstripped gas is without heavy hydrocarbon, directly cold through heat exchanger after methane rich unstripped gas is mixed with the pre- hot gas in part
But, then after reducing pressure by regulating flow, gas-liquid separation is carried out, liquefying high methane gas, low-flash gas are respectively obtained after separation, liquefaction is the richest in
Alkane gas is collected as product, and low-flash gas is pressurized after heat exchanger exchanges heat, into next circulation；
(2) open loop refrigeration:
The operation of the step 2 is as follows: low-flash gas obtains pre- hot gas after heat exchanger exchanges heat, and pre- hot gas is carried out
Pressurization, is classified as first strand of material and second strand of material after pressurization, first strand of material and high methane gas are mixed into heat exchanger
The high methane gas liquefaction of step 1 is carried out, second strand of material is successively through heat exchanger pre-cooling, the first expander, object after expansion
Material the second expander is entered back into after heat exchanger exchanges heat, the material after the second expander again after heat exchanger exchanges heat with
Pre- hot gas mixing returns to pressurization, into next circulation；
Or low-flash gas obtains pre- hot gas after heat exchanger exchanges heat, pressurized pre- hot gas and high methane gas is complete
Mixing, is further divided into first strand of material and second strand of material, and first strand of material directly carries out the methane rich gas-liquid of step 1 into heat exchanger
Change, successively through heat exchanger pre-cooling, the first expander, the material after expansion enters back into second strand of material after heat exchanger exchanges heat
Second expander, the material after the second expander mix return pressurization after heat exchanger exchanges heat with pre- hot gas again, into
Enter next circulation；
Or second strand of material is directly entered the first expander, the material after expansion enters back into after heat exchanger exchanges heat
Two expanders, the material after the second expander mix return pressurization with pre- hot gas after heat exchanger exchanges heat again, enter
Next circulation；
Another replacement method is also provided, is included the following steps:
(1) high methane gas liquefies:
The operation of the step 1 is as follows: low-flash gas obtains pre- hot gas after heat exchanger exchanges heat, and pre- hot gas is carried out
Pressurization, and methane rich unstripped gas is mixed with pre- hot gas, mixed material is cooled to -10 ~ -90 DEG C through heat exchanger, enters back into weight
Hydrocarbon separator takes off heavy hydrocarbon, obtains low temperature dry gas, and low temperature dry gas after heat exchanger is cooling, through reducing pressure by regulating flow, then carries out gas-liquid point again
From respectively obtaining liquefying high methane gas, low-flash gas after separation, liquefying high methane gas is collected as product, low-flash gas
It after heat exchanger exchanges heat, is pressurized, into next circulation；
If methane rich unstripped gas is without heavy hydrocarbon, directly cold through heat exchanger after methane rich unstripped gas is mixed with the pre- hot gas in part
But, then after reducing pressure by regulating flow, gas-liquid separation is carried out, liquefying high methane gas, low-flash gas are respectively obtained after separation, liquefaction is the richest in
Alkane gas is collected as product, and low-flash gas is pressurized after heat exchanger exchanges heat, into next circulation；
(2) closed-loop refrigeration:
The operation of the step 2 is as follows: cooling medium is divided into cooling first material, cooling second material two after being pressurized
Stock material, cooling first material, which enters in the first expanding machine, to be expanded, and the material after the first expander returns after exchanging heat
Pressurization, into next circulation；Cooling second material is successively through cooler heat exchange, the second expander, through the second expanding machine
Material after expansion returns to pressurization after exchanging heat, into next circulation；
In the step 1, the pressure of methane rich unstripped gas is 1MPaG ~ 20MPaG, temperature is -30 ~ 60 DEG C or the richness
Methane feed gas is the self-evaporating steam of LNG storage tank.
In the step 1, low temperature dry gas is after heat exchanger is cooling, then carries out reducing pressure by regulating flow, and the series of throttling is level-one section
Stream, two-step throttle, three-level throttling or level Four throttling.
In the step 1, low temperature dry gas is after heat exchanger is cooling, then through reducing pressure by regulating flow, subsequently into the first gas-liquid separation
Device carries out gas-liquid separation, and the first liquid phase object, the first gas gas-phase objects are respectively obtained after separation, which is the methane rich that liquefies
Gas, first gas gas-phase objects are low-flash gas.
In the step 1, the first liquid phase object after reducing pressure by regulating flow, carries out gas-liquid separation into the second gas-liquid separator again,
Second liquid phase object, the second gas gas-phase objects are respectively obtained after separation, which is liquefying high methane gas, first gas gas-phase objects
It is low-flash gas with the second gas gas-phase objects.
Further include precooling step: external cooling device being connected with heat exchanger, by external cooling device heat exchanging device
Other component be pre-chilled.
The typical cryogen that the external cooling device uses is in propylene, propane, ammonia, freon, water, BOG, lithium bromide
It is one or more.
It is not easy liquefied gas containing methane and can be drawn from any material of system.
In step 2, according to the pressure and temperature of methane rich unstripped gas, mixed in the suitable position of system with pre- hot gas.
For the device of the aforementioned liquefied method of twin-stage swell refrigeration high methane gas, including high methane gas liquefaction system, open
Formula cycle refrigeration system；
The high methane gas liquefaction system includes the feedstock supply unit, heat exchanger, gas for conveying methane rich unstripped gas
Liquid/gas separator, the feedstock supply unit, heat exchanger, gas-liquid separator are sequentially connected by pipeline；
The open loop refrigeration system includes gas-liquid separator, heat exchanger, compressor, the first expanding machine, the second expansion
Machine, the gas-liquid separator, heat exchanger, compressor, the first expanding machine, the second expanding machine constitute open circulation system by pipeline
System；
Another alternative, including high methane gas liquefaction system, closed-loop refrigeration system are provided；
The high methane gas liquefaction system includes feedstock supply unit, heat exchanger, gas-liquid separator, compressor, the original
Material feeding mechanism, heat exchanger, gas-liquid separator, compressor are sequentially connected by pipeline；
The closed-loop refrigeration system includes compressor, heat exchanger, the first expanding machine, the second expanding machine, the compression
Machine, heat exchanger, the first expanding machine, the second expanding machine constitute closed circulation system by pipeline.
In the present invention, the not liquescent gas containing methane is (such as: one kind of nitrogen, hydrogen, argon gas, oxygen or helium
Or several) can be drawn in any material of high methane gas liquefaction system.It further include the external cooling matched with heat exchanger,
The cooling coolant used in outside is typically one of propylene, propane, ammonia, freon, water, BOG, lithium bromide or a variety of.
In conclusion by adopting the above-described technical solution, the beneficial effects of the present invention are:
It (1) is -35 DEG C ~ -50 DEG C into the temperature of charge of compound expansion machine, relative to existing swell refrigeration natural gas liquefaction
For technique, temperature is higher, and the requirement of compound expansion machine material is lower, and equipment investment is smaller.
(2) material is full gas phase after the expansion of compound expansion machine, and the power of expanding machine is smaller；Meanwhile pressure drop is smaller, energy consumption compared with
It is low.
(3) in the present invention, expansion work can be passed to compression set by expanding machine, and energy consumption, save the cost is effectively reduced.
(4) present invention does not require enter compound expansion machine temperature of charge it is higher than the temperature of charge for going out one-stage expansion machine, adjust
Section means are abundant, flexible operation.
(5) heavy hydrocarbon removing is conducive to using the present invention, there is preferable effect.
(6) for material using throttling step by step, pressure drops at different levels are small after heat exchanger condensation, so that energy consumption is lower, methane losses are small, nitrogen
Gas separation is high.
Detailed description of the invention
Examples of the present invention will be described by way of reference to the accompanying drawings, in which:
Fig. 1 is the schematic illustration of embodiment 1.
In Fig. 1, T1 is pretreatment system, and P1, P2 are respectively expanding machine, and C1, C2, C3 are respectively recycle gas compressor, E1,
E2, E3 are respectively cooler, and E4 is heat exchanger, and V2 is heavy hydrocarbon separator, and V1 is gas-liquid separator, and V3 is LNG storage tank, and I, II divide
It Wei not throttle valve.
Fig. 2 is the schematic illustration of embodiment 2.
In Fig. 2, T1 is pretreatment system, and P1, P2 are respectively expanding machine, and C1, C2 are respectively recycle gas compressor, E1, E2
Respectively cooler, E3 are heat exchanger, and V2 is heavy hydrocarbon separator, and V1 is gas-liquid separator, and V3 is LNG storage tank, and I, II are respectively
Throttle valve.
Fig. 3 is the schematic illustration of embodiment 3.
In Fig. 3, T1 is pretreatment system, and P1, P2 are respectively expanding machine, and C1, C2 are respectively methane flash gas compression machine,
C3, C4 are respectively methane rich recycle gas compressor, and E1, E2, E3, E4 are respectively cooler, and E5 is heat exchanger, and V1 is separator,
V2 is heavy hydrocarbon separator, and V3 is LNG storage tank, and I, II are respectively throttle valve.
Specific embodiment
All features disclosed in this specification or disclosed all methods or in the process the step of, in addition to mutually exclusive
Feature and/or step other than, can combine in any way.
Any feature disclosed in this specification unless specifically stated can be equivalent or with similar purpose by other
Alternative features are replaced.That is, unless specifically stated, each feature is an example in a series of equivalent or similar characteristics
?.
Embodiment 1
The flow diagram of the present embodiment is as shown in Figure 1, this process includes pretreatment system (T1), expanding machine (P1, P2),
Recycle gas compressor (C1, C2, C3), cooler (E1, E2, E3), heat exchanger (E4), heavy hydrocarbon separator (V2), gas-liquid separator
(V1), LNG storage tank (V3), throttle valve I, throttle valve II etc., between each component by pipeline constitute high methane gas liquefaction system and
Open loop refrigeration system.
The work step of the present embodiment is as follows:
(1) high methane gas liquefies:
After unprocessed methane rich unstripped gas 1 preprocessed system T1 processing, methane rich unstripped gas 2 is obtained.Methane rich is former
Material gas 2 hereinafter mentioned with the pre- hot gas 19(in part) mix after obtain material 3, into heat exchanger E4 cool down after, obtain material 4.
Material 4 goes out heat exchanger E4, takes off heavy hydrocarbon into heavy hydrocarbon separator V2, heavy hydrocarbon is drawn by material 6, and low temperature dry gas material 5, which enters back into, to be changed
Hot device E4 cooling obtains material 7.Material 7 is drawn into heat exchanger E4, after level-one throttle valve I throttling, obtains material 8.Material 8 into
Enter level-one gas-liquid separator V1 and carry out gas-liquid separation, continues second level through the isolated liquid phase 10 of level-one gas-liquid separator V1
Throttling draws pre- hot gas 11 after level-one gas-liquid separator V1 isolated low-flash gas 9 enters heat exchanger E4 re-heat.
Pre- hot gas 11 draws material 12 and material 13, and material 12 is drawn out-of-bounds as liquefied gas is not easy, and material 13 and material 28(are hereinafter
Mention) it is mixed to get material 14, material 14 and material 32(are hereinafter mentioned) it is mixed to get material 15.Material 15 enters circulating air
Compressor C3 pressurization, the material 16 drawn after pressurization are divided after cooler E3 is cooling by material 17 for material 18 and material 19, object
Material 19 is mixed with methane rich unstripped gas 2, into next circulation.
The liquid phase 10 that level-one gas-liquid separator V1 is isolated obtains material 20 after two-step throttle valve II throttling.Material 20
Gas-liquid separation is carried out into LNG storage tank V3, isolated liquid-phase product is stored in tank, transports outward by material 21；It separates
After the low-flash gas 22 arrived enters heat exchanger E4 re-heat, pre- hot gas 23 is drawn, pre- hot gas 23 enters in recycle gas compressor C1
Pressurization, obtains material 24.Material 24 draws material 25 after cooler E1 is cooling, and material 25 and material 35(are hereinafter mentioned)
It is mixed to get material 26.Material 26 enters recycle gas compressor C2 and is pressurized, and the material 27 drawn after pressurization is cooling through cooler E2
Material 28 is drawn afterwards, and material 28 is mixed with material 13, obtains material 14.
(2) open loop refrigeration:
Pressurized material 17 is divided into material 18,19 two parts of material, and material 18 is further divided into material 29, material 30.Material
After 29 enter heat exchanger E4 cooling, material 33 is obtained, material 33 enters the second expanding machine P2, and material 34, material are drawn after expansion
34, which enter heat exchanger E4, exchanges heat, and material 35 is obtained after heat exchange.After material 35 is mixed with material 25, into next circulation.Material
30 enter the first expanding machine P1, and material 31 is drawn after expansion, and material 31 obtains material 32 after heat exchanger E4 heat exchange.Material 32
After being mixed with material 14, into next circulation.
In the present embodiment, the temperature of methane rich unstripped gas 2 is 40 DEG C, pressure 5000kPaA；It is not easy liquefied gas (i.e. material
It 12) is 37 DEG C, pressure 1080kPaA；The temperature of product LNG is -158.0 DEG C, pressure 120kPaA, unit product liquefaction energy
Consume 0.20 ~ 0.26kWh/Nm3LNG.It is absolute pressure.In the present embodiment, the expansion phase of the first expanding machine P1 and the second expanding machine P2
To independence, regulating measure is flexible, and the method and apparatus of the present embodiment are preferably applied in unstripped gas gas source condition and fluctuate biggish work
Condition.
Embodiment 2
The flow diagram of the present embodiment is as shown in Fig. 2, this process includes pretreatment system (T1), expanding machine (P1, P2),
Recycle gas compressor (C1, C2), cooler (E1, E2), heat exchanger (E3), heavy hydrocarbon separator (V2), gas-liquid separator (V1),
LNG storage tank (V3), throttle valve I, throttle valve II etc. constitute high methane gas liquefaction system by pipeline between each component and open type are followed
Ring refrigeration system.
The work step of the present embodiment is as follows:
(1) high methane gas liquefies:
After unprocessed methane rich unstripped gas 1 preprocessed system T1 processing, methane rich unstripped gas 2 is obtained.Methane rich is former
Material gas 2 is hereinafter mentioned with the pre- hot gas 19(in part) mix after obtain material 3, after the entrance of material 3 heat exchanger E3 is cooled down, obtain object
Material 4.Material 4 goes out heat exchanger E3, takes off heavy hydrocarbon into heavy hydrocarbon separator V2, and heavy hydrocarbon drawn by material 6, low temperature dry gas material 5 again into
Enter heat exchanger E3 cooling and obtains material 7.Material 7 is drawn into heat exchanger E3, after level-one throttle valve I throttling, obtains material 8.Object
Material 8 enter level-one gas-liquid separator V1 carry out gas-liquid separations, through the isolated liquid phase 10 of level-one gas-liquid separator V1 continue into
Row two-step throttle draws preheating after level-one gas-liquid separator V1 isolated low-flash gas 9 enters heat exchanger E3 re-heat
Gas 11.Pre- hot gas 11 draws material 12 and material 13, and material 12 is drawn out-of-bounds as liquefied gas is not easy, material 13 and material 30
(hereinafter mentioning) is mixed to get material 14, and material 14 and material 25(are hereinafter mentioned) it is mixed to get material 15.Material 15 into
Enter recycle gas compressor C2 pressurization, the material 16 drawn after pressurization is divided after cooler E2 is cooling by material 17 for 18 He of material
Material 19, material 19 are mixed with methane rich unstripped gas 2, into next circulation.
The liquid phase 10 that level-one gas-liquid separator V1 is isolated obtains material 20 after two-step throttle valve II throttling.Material 20
Gas-liquid separation is carried out into LNG storage tank V3, isolated liquid-phase product is stored in tank, transports outward by material 21；It separates
After the low-flash gas 22 arrived enters heat exchanger E4 re-heat, pre- hot gas 23 is drawn, pre- hot gas 23 enters in recycle gas compressor C1
Pressurization, obtains material 24.Material 24 draws material 25 after cooler E1 is cooling, and material 25 is mixed with material 14.
(2) open loop refrigeration:
Pressurized circulating air 17 is divided into material 18,19 two parts of material and obtains after material 18 enters heat exchanger E3 cooling
Material 26, material 26 enter the first expanding machine P1, and material 27 is drawn after expansion and is obtained after material 27 enters heat exchanger E3 heat exchange
Material 28.Material 28 enters the second expanding machine P2, and material 29 is drawn after expansion and is obtained after material 29 enters heat exchanger E3 heat exchange
Material 30.After material 30 is mixed with material 13, into next circulation.
In the present embodiment, the temperature of methane rich unstripped gas 2 is 40 DEG C, pressure 6000kPaA；It is not easy liquefied gas (i.e. material
It 12) is 37 DEG C, pressure 1080kPaA；The temperature of product LNG is -161.5 DEG C, pressure 120kPaA, unit product liquefaction energy
Consume 0.20 ~ 0.28kWh/Nm3LNG.It is absolute pressure.In the present embodiment, the expansion of the second expanding machine P2 is smaller, and lectotype selection is held
Easily, but the first expanding machine P1 connects with the second expanding machine P2, and regulating measure is slightly worse, the method and apparatus prior applicability of the present embodiment
Lesser operating condition is fluctuated in unstripped gas gas source condition.
Embodiment 3
The flow diagram of the present embodiment is as shown in figure 3, this process includes pretreatment system (T1), expanding machine (P1, P2),
Methane flash gas compression machine (C1, C2), methane rich recycle gas compressor (C3, C4), cooler (E1, E2, E3, E4), heat exchanger
(E5), separator (V1), heavy hydrocarbon separator (V2), LNG storage tank (V3), throttle valve I, throttle valve II etc. pass through between each component
Pipeline constitutes high methane gas liquefaction system and closed-loop refrigeration system.
The work step of the present embodiment is as follows:
(1) high methane gas liquefies:
After unprocessed methane rich unstripped gas 1 preprocessed system T1 processing, methane rich unstripped gas 2 is obtained.Methane rich is former
Material gas 2 obtains material 3 after mixing with pre- hot gas 16, into after heat exchanger E5 cooling, obtains material 4.Material 4 goes out heat exchanger E5,
Take off heavy hydrocarbon into heavy hydrocarbon separator V2, heavy hydrocarbon drawn by material 6, the low temperature dry gas material 5 obtained through heavy hydrocarbon separator V2 again into
It is cooling to enter heat exchanger E5, obtains material 7.Material 7 is drawn into heat exchanger E5, after level-one throttle valve I throttling, obtains material 8.Object
Material 8 enter level-one gas-liquid separator V1 carry out gas-liquid separations, through the isolated liquid phase 10 of level-one gas-liquid separator V1 continue into
Row two-step throttle draws preheating after level-one gas-liquid separator V1 isolated low-flash gas 9 enters heat exchanger E5 re-heat
Gas 11.Pre- hot gas 11 draws material 12 and material 13, and material 12 is drawn out-of-bounds as liquefied gas is not easy, material 13 and material 22
(hereinafter mentioning) is mixed to get material 14, and material 14 enters recycle gas compressor C2 and is pressurized, and the material 15 drawn after pressurization passes through
Material 16 is obtained after cooler E2 is cooling, material 16 is mixed with methane rich unstripped gas 2, into next circulation.
The liquid phase 10 that level-one gas-liquid separator V1 is isolated obtains material 17 after two-step throttle valve II throttling.Material 17
Gas-liquid separation is carried out into LNG storage tank V3, isolated liquid-phase product is stored in tank, transports outward by material 18；It separates
After the low-flash gas 19 arrived enters heat exchanger E5 re-heat, pre- hot gas 20 is drawn, pre- hot gas 20 enters in recycle gas compressor C1
Pressurization, obtains material 21.Material 21 draws material 22 after cooler E1 is cooling, and material 22 is mixed with material 13.
(2) closed-loop refrigeration:
In the present embodiment, using high methane gas as the cryogen of closed-loop refrigeration.High methane gas recycles air pressure through methane rich
After contracting machine C4 pressurization, material 23 is drawn.Material 23 obtains material 24 after cooler E4 is cooling.Material 24 divides for material 25, object
Material 26, material 25 are further cooled down into heat exchanger E5, obtain material 29.Material 29 obtains after the second expanding machine P2 expansion
Material 30.After material 30 enters heat exchanger E5 heat exchange, and material 31 is drawn, material 31 enters methane rich recycle gas compressor C3 and increases
Pressure, obtains material 32.Material 32 obtains material 33 after cooler E3 is cooling.Material 33 is mixed with material 28, obtains material
34.Material 34 enters recycle gas compressor C4, starts next circulation.Material 26 obtains object after the first expanding machine P1 expansion
Material 27.Material 27 enters heat exchanger E5 and exchanges heat, and draws material 28, and material 28 is mixed with material 33.
In the present embodiment, the temperature of methane rich unstripped gas 2 is 40 DEG C, pressure 6000kPaA；It is not easy liquefied gas (i.e. material
It 12) is 37 DEG C, pressure 1080kPaA；The temperature of product LNG is -162.5 DEG C, pressure 120kPaA, unit product liquefaction energy
Consume 0.20 ~ 0.25kWh/Nm3LNG.It is absolute pressure.In the present embodiment, high methane gas liquefaction system and closed-loop refrigeration system
Relatively independent, liquefaction flow path is not limited by unstripped gas gas source condition, and the method and apparatus of the present embodiment are preferably applied in unstripped gas
Gas source condition fluctuates the higher operating condition of hydro carbons containing heavy constituent in big or unstripped gas.
As a kind of alternative of the present embodiment, the first expanding machine P1 and the second expanding machine P2 can be according to embodiments 2
Form series connection, complete closed-loop refrigeration operation.
The invention is not limited to specific embodiments above-mentioned.The present invention, which expands to, any in the present specification to be disclosed
New feature or any new combination, and disclose any new method or process the step of or any new combination.
Claims (9)
1. a kind of liquefied method of twin-stage swell refrigeration high methane gas, which comprises the steps of:
(1) high methane gas liquefies:
The operation of the step 1 is as follows: after methane rich unstripped gas is mixed with the pre- hot gas in part, being cooled to -10 ~ -90 through heat exchanger
DEG C, it entering back into heavy hydrocarbon separator and takes off heavy hydrocarbon, obtain low temperature dry gas, low temperature dry gas is again after heat exchanger is cooling, through reducing pressure by regulating flow, then
Gas-liquid separation is carried out, liquefying high methane gas, low-flash gas are respectively obtained after separation, liquefying high methane gas is collected as product,
Low-flash gas is pressurized after heat exchanger exchanges heat, into next circulation；
It is directly cooling through heat exchanger after methane rich unstripped gas is mixed with the pre- hot gas in part if methane rich unstripped gas is without heavy hydrocarbon, then
After reducing pressure by regulating flow, gas-liquid separation is carried out, liquefying high methane gas, low-flash gas, liquefying high methane gas are respectively obtained after separation
It is collected as product, low-flash gas is pressurized after heat exchanger exchanges heat, into next circulation；
(2) open loop refrigeration:
The operation of the step 2 is as follows: low-flash gas obtains pre- hot gas after heat exchanger exchanges heat, and pre- hot gas is pressurized,
First strand of material, second strand of material and three strands of materials are classified as after pressurization, first strand of material is mixed with methane rich unstripped gas
Into heat exchanger, second strand of material enters the first expander, the material after expansion enter after heat exchanger heat exchange with pre- hot gas
Mixing returns to pressurization, into next circulation；Three strands of materials sequentially enters heat exchanger cooling, the second expander, expansion
Material afterwards enters heat exchanger heat exchange, return pressurization is mixed after heat exchange with pre- hot gas, into next circulation；
Or low-flash gas obtains pre- hot gas after heat exchanger exchanges heat, then will be complete with methane rich unstripped gas after pre- hot gas supercharged gas
Mixing, is then divided into first strand of material, second strand of material and three strands of materials, and first strand of material is directly into heat exchanger, and second strand
Material enters the first expander, and the material after expansion mixes return pressurization with pre- hot gas after entering heat exchanger heat exchange, enters
Next circulation；Three strands of materials sequentially enters heat exchanger cooling, the second expander, and the material after expansion enters heat exchanger
Heat exchange mixes return pressurization, into next circulation with pre- hot gas after heat exchange；
Another replacement method is provided, is included the following steps:
(1) high methane gas liquefies:
The operation of the step 1 is as follows: after methane rich unstripped gas is mixed with the pre- hot gas in part, being cooled to -10 ~ -90 through heat exchanger
DEG C, it entering back into heavy hydrocarbon separator and takes off heavy hydrocarbon, obtain low temperature dry gas, low temperature dry gas is again after heat exchanger is cooling, through reducing pressure by regulating flow, then
Gas-liquid separation is carried out, liquefying high methane gas and low-flash gas are respectively obtained after separation, liquefying high methane gas is collected as product,
Low-flash gas is pressurized after heat exchanger exchanges heat, into next circulation；
It is directly cooling through heat exchanger after methane rich unstripped gas is mixed with the pre- hot gas in part if methane rich unstripped gas is without heavy hydrocarbon, then
After reducing pressure by regulating flow, gas-liquid separation is carried out, liquefying high methane gas, low-flash gas, liquefying high methane gas are respectively obtained after separation
It is collected as product, low-flash gas is pressurized after heat exchanger exchanges heat, into next circulation；
(2) open loop refrigeration:
The operation of the step 2 is as follows: low-flash gas obtains pre- hot gas after heat exchanger exchanges heat, and pre- hot gas is pressurized,
First strand of material and second strand of material are classified as after pressurization, first strand of material and methane rich unstripped gas are mixed into heat exchanger,
For second strand of material successively through heat exchanger pre-cooling, the first expander, the material after expansion enters back into the after heat exchanger exchanges heat
Two expanders, the material after the second expander mix return pressurization with pre- hot gas after heat exchanger exchanges heat again, enter
Next circulation；
Or low-flash gas obtains pre- hot gas after heat exchanger exchanges heat, pressurized pre- hot gas and methane rich unstripped gas is complete
Mixing, is further divided into first strand of material and second strand of material, first strand of material is directly into heat exchanger, and second strand of material is successively through exchanging heat
Device pre-cooling, the first expander, the material after expansion enter back into the second expander, the second expansion after heat exchanger exchanges heat
Material after machine expansion mixes return pressurization after heat exchanger exchanges heat with pre- hot gas again, into next circulation；
Or second strand of material is directly entered the first expander, it is swollen that the material after expansion enters back into second after heat exchanger exchanges heat
Swollen machine expands, and the material after the second expander mixes return pressurization after heat exchanger exchanges heat with pre- hot gas again, and entrance is next
A circulation；
Another replacement method is provided, is included the following steps:
(1) high methane gas liquefies:
The operation of the step 1 is as follows: low-flash gas obtains pre- hot gas after heat exchanger exchanges heat, and pre- hot gas is pressurized,
And mix methane rich unstripped gas with pre- hot gas, mixed material is cooled to -10 ~ -90 DEG C through heat exchanger, enters back into heavy hydrocarbon separation
Device takes off heavy hydrocarbon, obtains low temperature dry gas, and low temperature dry gas after heat exchanger is cooling, through reducing pressure by regulating flow, then carries out gas-liquid separation again, separates
After respectively obtain liquefying high methane gas, low-flash gas, liquefying high methane gas is collected as product, and low-flash gas is through heat exchanger
It after heat exchange, is pressurized, into next circulation；
It is directly cooling through heat exchanger after methane rich unstripped gas is mixed with the pre- hot gas in part if methane rich unstripped gas is without heavy hydrocarbon, then
After reducing pressure by regulating flow, gas-liquid separation is carried out, liquefying high methane gas, low-flash gas, liquefying high methane gas are respectively obtained after separation
It is collected as product, low-flash gas is pressurized after heat exchanger exchanges heat, into next circulation；
(2) closed-loop refrigeration:
The operation of the step 2 is as follows: cooling medium is divided into cooling first material, cooling two strands of objects of second material after being pressurized
Material, cooling first material, which enters in the first expanding machine, to be expanded, and the material after the first expander returns to pressurization after exchanging heat,
Into next circulation；Cooling second material is successively through cooler heat exchange, the second expander, after the second expander
Material pressurization is returned after exchanging heat, into next circulation；
In the step 1, the pressure of methane rich unstripped gas is 1MPaG ~ 20MPaG, temperature is -30 ~ 60 DEG C or the methane rich
Unstripped gas is the self-evaporating steam of LNG storage tank.
2. the liquefied method of twin-stage swell refrigeration high methane gas according to claim 1, which is characterized in that in the step 1,
Low temperature dry gas is after heat exchanger is cooling, then carries out reducing pressure by regulating flow, and the series of throttling is level-one throttling, two-step throttle, three-level throttling
Or level Four throttling.
3. the liquefied method of twin-stage swell refrigeration high methane gas according to claim 2, which is characterized in that in the step 1,
Low temperature dry gas carries out gas-liquid separation subsequently into the first gas-liquid separator, after separation after heat exchanger is cooling, then through reducing pressure by regulating flow
The first liquid phase object, the first gas gas-phase objects are respectively obtained, which is liquefying high methane gas, and first gas gas-phase objects are as low
Warm flashed vapour.
4. the liquefied method of twin-stage swell refrigeration high methane gas according to claim 3, which is characterized in that in the step 1,
First liquid phase object after reducing pressure by regulating flow, carries out gas-liquid separation into the second gas-liquid separator, the second liquid is respectively obtained after separation again
Phase object, the second gas gas-phase objects, which is liquefying high methane gas, and first gas gas-phase objects and the second gas gas-phase objects are low temperature
Flashed vapour.
5. any one liquefied method of twin-stage swell refrigeration high methane gas according to claim 1 ~ 4, which is characterized in that also wrap
Include precooling step: external cooling device be connected with heat exchanger, by the other component in external cooling device heat exchanging device into
Row pre-cooling.
6. the liquefied method of twin-stage swell refrigeration high methane gas according to claim 5, which is characterized in that described external cooling
The typical cryogen that device uses is one of propylene, propane, ammonia, freon, water, BOG, lithium bromide or a variety of.
7. the liquefied method of twin-stage swell refrigeration high methane gas according to claim 1, which is characterized in that be not easy containing methane
Liquefied gas can be drawn from any material of system.
8. the liquefied method of twin-stage swell refrigeration high methane gas according to claim 1, which is characterized in that in step 2, according to
The pressure and temperature of methane rich unstripped gas is mixed in the suitable position of system with pre- hot gas.
9. the device of any one liquefied method of twin-stage swell refrigeration high methane gas, feature exist according to claim 1 ~ 8
In, including high methane gas liquefaction system, open loop refrigeration system；
The high methane gas liquefaction system includes for conveying the feedstock supply unit, heat exchanger, gas-liquid of methane rich unstripped gas point
From device, the feedstock supply unit, heat exchanger, gas-liquid separator are sequentially connected by pipeline；
The open loop refrigeration system includes gas-liquid separator, heat exchanger, compressor, the first expanding machine, the second expanding machine, institute
It states gas-liquid separator, heat exchanger, compressor, the first expanding machine, the second expanding machine and open loop refrigeration system is constituted by pipeline；
Another alternative, including high methane gas liquefaction system, closed-loop refrigeration system are provided；
The high methane gas liquefaction system includes feedstock supply unit, heat exchanger, gas-liquid separator, compressor, and the raw material supplies
Device, heat exchanger, gas-liquid separator, compressor is answered to be sequentially connected by pipeline；
The closed-loop refrigeration system includes compressor, heat exchanger, the first expanding machine, the second expanding machine, and the compressor changes
Hot device, the first expanding machine, the second expanding machine constitute closed-loop refrigeration system by pipeline.
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| CN107560321B (en) * | 2017-09-15 | 2023-04-25 | 长江大学 | BOG recovery and nitrogen liquefaction system and technological method |
| CN108036583B (en) * | 2018-01-15 | 2023-12-01 | 杭州中泰深冷技术股份有限公司 | Mixed alkane reaction product expansion refrigeration separation system and method thereof |
| US10866022B2 (en) * | 2018-04-27 | 2020-12-15 | Air Products And Chemicals, Inc. | Method and system for cooling a hydrocarbon stream using a gas phase refrigerant |
| US10788261B2 (en) * | 2018-04-27 | 2020-09-29 | Air Products And Chemicals, Inc. | Method and system for cooling a hydrocarbon stream using a gas phase refrigerant |
| CN109579432B (en) * | 2018-11-14 | 2020-06-26 | 西安交通大学 | Natural gas and electric power interconnection peak shaving system utilizing low-temperature liquefaction for energy storage |
| CN114576928A (en) * | 2020-11-30 | 2022-06-03 | 惠生工程（中国）有限公司 | Propane dehydrogenation reaction product cascade refrigeration separation system and method |
| CN113701446A (en) * | 2021-04-07 | 2021-11-26 | 中国科学院理化技术研究所 | Natural gas liquefaction system with supersonic two-phase expansion refrigeration cycle |
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| RU2039329C1 (en) * | 1989-04-05 | 1995-07-09 | Мобил Ойл Корпорейшн | Method and device for cryogenic separation of gas mixtures |
| CN101268324A (en) * | 2005-07-28 | 2008-09-17 | 英尼奥斯美国有限责任公司 | Recovery of CO-rich product from a mixed gas containing heavy hydrocarbons |
| GB2486036B (en) * | 2011-06-15 | 2012-11-07 | Anthony Dwight Maunder | Process for liquefaction of natural gas |
| CN104019626B (en) * | 2014-06-27 | 2016-08-24 | 成都赛普瑞兴科技有限公司 | The cold method and device preparing liquefied natural gas of a kind of azeotrope two-stage system |
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