CN111102027B - LNG cold energy cascade utilization system and control method - Google Patents
LNG cold energy cascade utilization system and control method Download PDFInfo
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- CN111102027B CN111102027B CN202010047850.2A CN202010047850A CN111102027B CN 111102027 B CN111102027 B CN 111102027B CN 202010047850 A CN202010047850 A CN 202010047850A CN 111102027 B CN111102027 B CN 111102027B
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- 238000000034 method Methods 0.000 title claims abstract description 47
- 239000003507 refrigerant Substances 0.000 claims abstract description 288
- 238000005057 refrigeration Methods 0.000 claims abstract description 39
- 238000010248 power generation Methods 0.000 claims abstract description 36
- 230000002159 abnormal effect Effects 0.000 claims abstract description 24
- 230000001105 regulatory effect Effects 0.000 claims description 121
- 238000003860 storage Methods 0.000 claims description 70
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 28
- 238000002309 gasification Methods 0.000 claims description 19
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 claims description 16
- 239000003345 natural gas Substances 0.000 claims description 16
- 238000011084 recovery Methods 0.000 claims description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- 238000009835 boiling Methods 0.000 claims description 12
- 239000007788 liquid Substances 0.000 claims description 11
- 239000001294 propane Substances 0.000 claims description 8
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 claims description 7
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims description 6
- 239000005977 Ethylene Substances 0.000 claims description 6
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 6
- 238000001816 cooling Methods 0.000 claims description 6
- NNPPMTNAJDCUHE-UHFFFAOYSA-N isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 claims description 6
- 238000007711 solidification Methods 0.000 claims description 6
- 230000008023 solidification Effects 0.000 claims description 6
- 238000007710 freezing Methods 0.000 claims description 4
- 230000008014 freezing Effects 0.000 claims description 4
- 239000013535 sea water Substances 0.000 claims description 4
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 3
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 claims description 3
- 239000001282 iso-butane Substances 0.000 claims description 3
- 238000003303 reheating Methods 0.000 claims description 3
- 239000007864 aqueous solution Substances 0.000 claims 3
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims 1
- 239000001110 calcium chloride Substances 0.000 claims 1
- 229910001628 calcium chloride Inorganic materials 0.000 claims 1
- 235000011148 calcium chloride Nutrition 0.000 claims 1
- 230000008569 process Effects 0.000 abstract description 28
- 238000004519 manufacturing process Methods 0.000 abstract description 11
- 239000003949 liquefied natural gas Substances 0.000 description 85
- 239000000243 solution Substances 0.000 description 14
- YMIFCOGYMQTQBP-UHFFFAOYSA-L calcium;dichloride;hydrate Chemical compound O.[Cl-].[Cl-].[Ca+2] YMIFCOGYMQTQBP-UHFFFAOYSA-L 0.000 description 9
- 238000010586 diagram Methods 0.000 description 8
- 238000004590 computer program Methods 0.000 description 7
- 238000009834 vaporization Methods 0.000 description 6
- 230000008016 vaporization Effects 0.000 description 6
- 230000006870 function Effects 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 239000002826 coolant Substances 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 239000002912 waste gas Substances 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 235000011089 carbon dioxide Nutrition 0.000 description 2
- 238000004134 energy conservation Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000012267 brine Substances 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000007363 regulatory process Effects 0.000 description 1
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K27/00—Plants for converting heat or fluid energy into mechanical energy, not otherwise provided for
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K25/00—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for
- F01K25/08—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using special vapours
- F01K25/10—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using special vapours the vapours being cold, e.g. ammonia, carbon dioxide, ether
-
- 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
- F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
- F25D3/00—Devices using other cold materials; Devices using cold-storage bodies
- F25D3/10—Devices using other cold materials; Devices using cold-storage bodies using liquefied gases, e.g. liquid air
Abstract
The invention provides an LNG cold energy cascade utilization system and a control method, which can ensure that when an abnormal working condition occurs in one process of a refrigerant expansion power generation subsystem, a refrigeration house area subsystem and a data center area subsystem, other areas are not affected to continue production, and other cold energy cascade processes can stop due to the abnormal working condition of one process. Therefore, the efficient LNG cold energy cascade utilization is realized, the temperature utilization range is wide, the relative independence of each process section of the LNG cold energy cascade utilization is improved, the operation elasticity and fault tolerance of the whole project are improved, the economic influence caused by faults is reduced, the safe production can be realized, the operation cost is reduced, the whole project is environment-friendly, the potential safety hazard is reduced to the minimum, and the implementation of other projects of a station is not influenced.
Description
Technical Field
The invention relates to the field of LNG cold energy utilization, in particular to an LNG cold energy cascade utilization system and a control method.
Background
Along with the continuous prominence of environmental problems, the energy consumption structure of China is correspondingly changed. Liquefied Natural Gas (LNG) has become an important strategic reserve energy source due to its advantages such as cleanliness and environmental protection. At present, china has become the largest natural gas importation country in the world, with importation LNG accounting for 53% of the total natural gas supply. In 2018, the total imported quantity of the Chinese LNG is approximately 5400 ten thousand tons, which is increased by 41.2 percent, the net imported increment is 1600 ten thousand tons, and the net imported increment accounts for 59.26 percent of the global increment, and is first in the world. In the future, china is still the country with the strongest demand for LNG market, and chinese LNG import capacity is expected to double in five years.
LNG is a low-temperature (-162 ℃) liquid mixture formed by deacidifying and dehydrating low-pollution natural gas and freezing and liquefying the low-temperature natural gas through a low-temperature process, and is used after being gasified by a gasifier in an LNG receiving station, and according to measurement and calculation, the gasification process of each ton of LNG is equivalent to the release of cold energy of 830MJ to 860 MJ. At present, china is greatly developing energy conservation and emission reduction, and recycling LNG cold energy, so that the LNG production cost is reduced, the energy conservation and emission reduction policies of China are met, and the method has important significance at present that fossil energy is gradually reduced and the demand is gradually increased. The LNG cold energy utilization modes are numerous, and the LNG cold energy utilization modes comprise LNG cold energy power generation, ice making, liquid CO2 and dry ice making, refrigeration houses, cryogenic crushing and the like.
Chinese patent CN110513932a discloses an LNG cold energy ice making system, which stores a coolant heat-exchanged with LNG in a coolant storage tank, and adjusts flow rates of LNG and the coolant to achieve stable operation of the LNG cold energy ice making system even when the gasification amount fluctuates greatly. However, the system does not realize gradient utilization of cold energy, and the cold energy utilization rate is low. Chinese patent CN105545390a uses coal-fired waste gas to heat the circulating working medium and LNG to cool the circulating working medium to realize that LNG cold energy is used for power generation, and simultaneously uses the coal-fired waste gas after LNG recooling after heat exchange with the circulating working medium and heat exchange with the circulating working medium to realize CO 2 Liquefying. The method realizes gradient utilization of the cold energy by using the LNG cold energy and the waste heat of the coal-fired waste gas in a combined way, but has poorer process flexibility, and if an LNG power generation system or CO 2 When the liquefaction system fails, the whole process flow is stopped, and the application under various working conditions cannot be well realized. The existing LNG cold energy utilization patent has no emergency measures when leakage and damage occur in the cold energy cascade utilization, the cold energy cascade utilization project is single, and the operation difficulty and the maintenance links are more.
Disclosure of Invention
The present invention aims to provide an LNG cold energy cascade utilization system and control method that overcomes or at least partially solves the above-mentioned problems.
In order to achieve the above purpose, the technical scheme of the invention is specifically realized as follows:
one aspect of the present invention provides an LNG cold energy cascade utilization system, comprising: the system comprises a cold energy recovery subsystem, a refrigerant expansion power generation area subsystem, a refrigeration house area subsystem and a data center area subsystem; wherein: the cold energy recovery subsystem includes: the LNG storage tank is connected with the first end of the first flow regulating valve 1 through the high-pressure output main pipe, the second end of the first flow regulating valve 1 is connected with the first end of the second flow regulating valve 2, the second end of the second flow regulating valve 2 is connected with the first end of the first heat exchanger 3, the second end of the first heat exchanger 3 is connected with the first end of the third flow regulating valve 5, the second end of the first heat exchanger 3 is connected with the first end of the second heat exchanger 4, the second end of the second heat exchanger 4 is connected with the first end of the third flow regulating valve 5, the second end of the first flow regulating valve 1 is connected with the first end of the fourth flow regulating valve 9, the second end of the fourth flow regulating valve 9 is connected with the first end of the third heat exchanger 8, the second end of the third heat exchanger 8 is connected with the third end of the third flow regulating valve 5, the third end of the third heat exchanger 8 is connected with the first end of the ninth flow regulating valve 7, the second end of the ninth flow regulating valve 7 is connected with the third end of the second heat exchanger 4, the third end of the third heat exchanger 8 is connected with the third end of the third heat exchanger 6, and the third end of the third heat exchanger 6 is connected with the third end of the third heat exchanger 6; the refrigerant expansion power generation zone subsystem comprises: the mixed refrigerant circulation loop and with mixed refrigerant storage tank 11, first mixed refrigerant force (forcing) pump 12 and first three-way valve 13 of mixed refrigerant circulation loop parallelly connected, wherein, mixed refrigerant circulation loop includes: the first end of the second mixed refrigerant pressurizing pump 14 is connected with the third end of the first heat exchanger 3, the second end of the second mixed refrigerant pressurizing pump 14 is connected with the first end of the fourth heat exchanger 15, the second end of the fourth heat exchanger 15 is connected with the first end of the fifth heat exchanger 16, the second end of the fifth heat exchanger 16 is connected with the first end of the expander 17, the second end of the expander 17 is connected with the fourth end of the first heat exchanger 3, the third end of the expander 17 is connected with the first end of the generator 10, the second end of the generator 10 is connected with a power supply port, the first end of the sixth flow regulating valve 18 is connected with the third end of the third heat exchanger 8, the second end of the sixth flow regulating valve 18 is connected with the third end of the fourth heat exchanger 15, and the fourth end of the fourth heat exchanger 15 is connected with the fourth end of the third heat exchanger 8; the first end of the first three-way valve 13 is connected with the third end of the first heat exchanger 3, the second end of the first three-way valve 13 is connected with the first end of the mixed refrigerant storage tank 11, the second end of the mixed refrigerant storage tank 11 is connected with the first end of the first mixed refrigerant pressurizing pump 12, the second end of the first mixed refrigerant pressurizing pump 12 is connected with the third end of the first three-way valve 13, and the third end of the first three-way valve 13 is connected with the first end of the second mixed refrigerant pressurizing pump 14; the cold store area subsystem includes: a single-component refrigerant circulation circuit, the single-component refrigerant circulation circuit comprising: the first end of the first single-component refrigerant pressurizing pump 27 is connected with the fourth end of the third heat exchanger 8, the second end of the first single-component refrigerant pressurizing pump 27 is connected with the first end of the fifth flow regulating valve 28, the second end of the fifth flow regulating valve 28 is connected with the first end of the eighth heat exchanger 29, the second end of the eighth heat exchanger 29 is connected with the third end of the third heat exchanger 8, and the third end of the eighth heat exchanger 29 and the fourth end of the eighth heat exchanger 29 are connected with a cold storage area; the data center area subsystem includes: the first end of the second three-way valve 21 is connected with the fourth end of the third heat exchanger 8, the second end of the second three-way valve 21 is connected with the first end of the single-component refrigerant storage tank 19, the second end of the single-component refrigerant storage tank 19 is connected with the first end of the second single-component refrigerant pressurizing pump 20, the second end of the second single-component refrigerant pressurizing pump 20 is connected with the third end of the second three-way valve 21, the third end of the second three-way valve 21 is connected with the first end of the sixth heat exchanger 26, the second end of the sixth heat exchanger 26 is connected with the first end of the eighth flow regulating valve 25, the second end of the eighth flow regulating valve 25 is connected with the third end of the third heat exchanger 8, the third end of the second three-way valve 21 is connected with the first end of the third single-component refrigerant pressurizing pump 22, the second end of the third single-component refrigerant pump 22 is connected with the first end of the seventh flow regulating valve 23, the second end of the seventh flow regulating valve 23 is connected with the first end of the seventh heat exchanger 24, the second end of the seventh heat exchanger 24 is connected with the third end of the third heat exchanger 8, the second end of the seventh heat exchanger 24 is connected with the third end of the seventh heat exchanger 24, the third end of the seventh heat exchanger 24 is connected with the third data center.
Wherein, the mixed refrigerant circulation loop is filled with mixed refrigerant; the single-component refrigerant circulation loop is filled with single-component phase-change refrigerant.
Wherein, the mixed refrigerant comprises a light component and a heavy component; the mass ratio of the light component to the heavy component is 5:5-3:7; the freezing point of the light component is lower than the liquefaction temperature of LNG, and the boiling point is higher than the liquefaction temperature of LNG; the boiling point of the heavy component at the working pressure is higher than the solidification temperature point of the single-component refrigerant; the boiling point of the single-component refrigerant is higher than the solidification temperature point of the secondary refrigerant at the working pressure.
Wherein the boiling point of the light component is above 30 ℃ higher than the liquefaction temperature of LNG.
Wherein the light component comprises propane, ethylene and/or ethane; the heavy components comprise isobutane, R134A, R410A and/or R22; the single-component refrigerant comprises propane, ethylene and/or ethane, and the secondary refrigerant comprises CaCl2 water solution, naCl water solution and/or glycol water solution.
Wherein, the inlet temperature of the single-component refrigerant is between-8 and-12 ℃, and the outlet temperature is between-28 and-34 ℃.
Wherein, the reheater 6 is a water bath type reheater.
Wherein each heat exchanger is a shell-and-tube heat exchanger.
The invention further provides an LNG cold energy cascade utilization control method utilizing the LNG cold energy cascade utilization system, which comprises the following steps: the cold energy recovery subsystem adopts a mixed refrigerant as a refrigerant in the refrigerant expansion power generation area, and adopts a single-component refrigerant as a refrigerant in the cold storage area and a refrigerant in the data center; after the LNG in the LNG storage tank and the mixed refrigerant are subjected to heat exchange and gasification, the LNG is subjected to heat exchange and temperature rise with the single-component refrigerant, and then is subjected to seawater reheating to 0 ℃ and then is sent to an output pipeline network; the subsystem of the refrigerant expansion power generation area is that the mixed refrigerant is pressurized and heated by hot water, and then enters an expander to expand and do work, the expander drives a generator to operate to generate power, the mixed refrigerant is expanded and depressurized, the temperature is reduced, and the mixed refrigerant enters a mixed refrigerant storage tank to be recycled; the cold storage area subsystem and the data center area subsystem are that the gaseous single-component refrigerant enters a heat exchanger to exchange heat with the low-temperature natural gas, the low-temperature liquid single-component refrigerant is divided into two parts, one part exchanges heat with the secondary refrigerant from the cold storage, the temperature rises to be gaseous, and then the next cycle is carried out; the second-stage refrigerant exchanges heat and then enters a refrigeration house for refrigeration, and after the temperature is raised, the second-stage refrigerant enters the next cycle; the other strand exchanges heat with the secondary refrigerant from the data center, the temperature rises to be gaseous, and then the next cycle is carried out; the second-stage refrigerant exchanges heat and then enters a data center for refrigeration, and after the temperature is raised, the second-stage refrigerant enters the next cycle.
Wherein the method further comprises: when the subsystem of the refrigerant expansion power generation area has abnormal working conditions, the second flow regulating valve, the sixth flow regulating valve and the eighth flow regulating valve are closed to cut off the mixed refrigerant circulation loop; increasing the opening of the eighth flow regulating valve to maintain the normal cooling of the data center and the refrigeration house; increasing the flow of LNG entering the original gasification pressure regulating system of the plant so as to maintain the normal gasification of the LNG; when abnormal working conditions occur in the subsystem in the data center area, the seventh flow regulating valve is closed to stop the single-component refrigerant from entering the seventh heat exchanger to exchange heat with the secondary refrigerant; closing a ninth flow regulating valve to reduce the heat exchange amount of the single-component refrigerant circulation loop; when the subsystem in the cold storage area has abnormal working conditions, the fifth flow regulating valve is closed to stop the single-component refrigerant from entering the eighth heat exchanger to exchange heat with the secondary refrigerant, and the ninth flow regulating valve is closed to reduce the heat exchange quantity of the single-component refrigerant circulation loop.
Therefore, according to the LNG cold energy cascade utilization system and the control method, when an abnormal working condition occurs in one process of the refrigerant expansion power generation subsystem, the refrigeration house area subsystem and the data center area subsystem, other areas are not affected to continue production, and other cold energy cascade processes can stop due to the abnormal working condition of one process. Therefore, the efficient LNG cold energy cascade utilization is realized, the temperature utilization range is wide, the relative independence of each process section of the LNG cold energy cascade utilization is improved, the operation elasticity and fault tolerance of the whole project are improved, the economic influence caused by faults is reduced, the safe production can be realized, the operation cost is reduced, the whole project is environment-friendly, the potential safety hazard is reduced to the minimum, and the implementation of other projects of a station is not influenced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of an LNG cold energy cascade utilization system according to an embodiment of the present invention.
The figure shows: 1-first flow regulating valve, 2-second flow regulating valve, 3-first heat exchanger, 4-second heat exchanger, 5-third flow regulating valve, 6-reheater, 7-ninth flow regulating valve, 8-third heat exchanger, 9-fourth flow regulating valve, 10-generator, 11-mixed refrigerant storage tank, 12-first mixed refrigerant pressurizing pump, 13-first three-way valve, 14-second mixed refrigerant pressurizing pump, 15-fourth heat exchanger, 16-fifth heat exchanger, 17-expander, 18-sixth flow regulating valve, 19-single-component refrigerant storage tank, 20-second single-component refrigerant pressurizing pump, 21-second three-way valve, 22-third single-component refrigerant pressurizing pump, 23-seventh flow regulating valve, 24-seventh heat exchanger, 25-eighth flow regulating valve, 26-sixth heat exchanger, 27-first single-component refrigerant pressurizing pump, 28-fifth flow regulating valve, 29-eighth heat exchanger.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
Fig. 1 shows a schematic structural diagram of an LNG cold energy cascade utilization system provided by an embodiment of the present invention, referring to fig. 1, the LNG cold energy cascade utilization system provided by the embodiment of the present invention includes:
the system comprises a cold energy recovery subsystem, a refrigerant expansion power generation area subsystem, a refrigeration house area subsystem and a data center area subsystem; wherein:
the cold energy recovery subsystem includes: the LNG storage tank is connected with the first end of the first flow regulating valve 1 through the high-pressure output main pipe, the second end of the first flow regulating valve 1 is connected with the first end of the second flow regulating valve 2, the second end of the second flow regulating valve 2 is connected with the first end of the first heat exchanger 3, the second end of the first heat exchanger 3 is connected with the first end of the third flow regulating valve 5, the second end of the first heat exchanger 3 is connected with the first end of the second heat exchanger 4, the second end of the second heat exchanger 4 is connected with the first end of the third flow regulating valve 5, the second end of the first flow regulating valve 1 is connected with the first end of the fourth flow regulating valve 9, the second end of the fourth flow regulating valve 9 is connected with the first end of the third heat exchanger 8, the second end of the third heat exchanger 8 is connected with the third end of the third flow regulating valve 5, the third end of the third heat exchanger 8 is connected with the first end of the ninth flow regulating valve 7, the second end of the ninth flow regulating valve 7 is connected with the third end of the second heat exchanger 4, the third end of the third heat exchanger 8 is connected with the third end of the third heat exchanger 6, and the third end of the third heat exchanger 6 is connected with the third end of the third heat exchanger 6;
The refrigerant expansion power generation zone subsystem comprises: the mixed refrigerant circulation loop and with mixed refrigerant storage tank 11, first mixed refrigerant force (forcing) pump 12 and first three-way valve 13 of mixed refrigerant circulation loop parallelly connected, wherein, mixed refrigerant circulation loop includes: the first end of the second mixed refrigerant pressurizing pump 14 is connected with the third end of the first heat exchanger 3, the second end of the second mixed refrigerant pressurizing pump 14 is connected with the first end of the fourth heat exchanger 15, the second end of the fourth heat exchanger 15 is connected with the first end of the fifth heat exchanger 16, the second end of the fifth heat exchanger 16 is connected with the first end of the expander 17, the second end of the expander 17 is connected with the fourth end of the first heat exchanger 3, the third end of the expander 17 is connected with the first end of the generator 10, the second end of the generator 10 is connected with a power supply port, the first end of the sixth flow regulating valve 18 is connected with the third end of the third heat exchanger 8, the second end of the sixth flow regulating valve 18 is connected with the third end of the fourth heat exchanger 15, and the fourth end of the fourth heat exchanger 15 is connected with the fourth end of the third heat exchanger 8; the first end of the first three-way valve 13 is connected with the third end of the first heat exchanger 3, the second end of the first three-way valve 13 is connected with the first end of the mixed refrigerant storage tank 11, the second end of the mixed refrigerant storage tank 11 is connected with the first end of the first mixed refrigerant pressurizing pump 12, the second end of the first mixed refrigerant pressurizing pump 12 is connected with the third end of the first three-way valve 13, and the third end of the first three-way valve 13 is connected with the first end of the second mixed refrigerant pressurizing pump 14;
The cold store area subsystem includes: a single-component refrigerant circulation circuit, the single-component refrigerant circulation circuit comprising: the first end of the first single-component refrigerant pressurizing pump 27 is connected with the fourth end of the third heat exchanger 8, the second end of the first single-component refrigerant pressurizing pump 27 is connected with the first end of the fifth flow regulating valve 28, the second end of the fifth flow regulating valve 28 is connected with the first end of the eighth heat exchanger 29, the second end of the eighth heat exchanger 29 is connected with the third end of the third heat exchanger 8, and the third end of the eighth heat exchanger 29 and the fourth end of the eighth heat exchanger 29 are connected with a cold storage area;
the data center area subsystem includes: the first end of the second three-way valve 21 is connected with the fourth end of the third heat exchanger 8, the second end of the second three-way valve 21 is connected with the first end of the single-component refrigerant storage tank 19, the second end of the single-component refrigerant storage tank 19 is connected with the first end of the second single-component refrigerant pressurizing pump 20, the second end of the second single-component refrigerant pressurizing pump 20 is connected with the third end of the second three-way valve 21, the third end of the second three-way valve 21 is connected with the first end of the sixth heat exchanger 26, the second end of the sixth heat exchanger 26 is connected with the first end of the eighth flow regulating valve 25, the second end of the eighth flow regulating valve 25 is connected with the third end of the third heat exchanger 8, the third end of the second three-way valve 21 is connected with the first end of the third single-component refrigerant pressurizing pump 22, the second end of the third single-component refrigerant pump 22 is connected with the first end of the seventh flow regulating valve 23, the second end of the seventh flow regulating valve 23 is connected with the first end of the seventh heat exchanger 24, the second end of the seventh heat exchanger 24 is connected with the third end of the third heat exchanger 8, the second end of the seventh heat exchanger 24 is connected with the third end of the seventh heat exchanger 24, the third end of the seventh heat exchanger 24 is connected with the third data center.
Specifically, the LNG cold energy cascade utilization system provided by the embodiment of the invention can comprise a cold energy recovery subsystem, a refrigerant expansion power generation region subsystem, a refrigeration house region subsystem and a data center region subsystem.
Wherein, cold energy recovery subsystem includes: the first flow regulating valve 1, the second flow regulating valve 2, the third flow regulating valve 5, the fourth flow regulating valve 9, the ninth flow regulating valve 7, the first heat exchanger 3, the second heat exchanger 4, the third heat exchanger 8 and the reheater 6 can be connected between the LNG storage tank and the main gas pipe network in a connecting mode shown in fig. 1 through pipelines.
The refrigerant expansion power generation zone subsystem comprises: the mixed refrigerant circulation loop and with mixed refrigerant storage tank 11, first mixed refrigerant force (forcing) pump 12 and first three-way valve 13 of mixed refrigerant circulation loop parallelly connected, wherein, mixed refrigerant circulation loop includes: the second mixed refrigerant pressurizing pump 14, the sixth flow rate adjusting valve 18, the fourth heat exchanger 15, the fifth heat exchanger 16, the expander 17, and the generator 10 may be sequentially connected to form a mixed refrigerant circulation loop in a manner as shown in fig. 1.
The cold store area subsystem includes: a single-component refrigerant circulation circuit, the single-component refrigerant circulation circuit comprising: the first single-component refrigerant pressurizing pump 27, the fifth flow rate adjusting valve 28, and the eighth heat exchanger 29 may be sequentially connected to form a single-component refrigerant circulation loop in a manner as shown in fig. 1.
The data center area subsystem comprises a seventh flow regulating valve 23, an eighth flow regulating valve 25, a sixth heat exchanger 26, a seventh heat exchanger 24, a second single-component refrigerant pressurizing pump 20, a third single-component refrigerant pressurizing pump 22, a second three-way valve 21 and a single-component refrigerant storage tank 19. The branch lines formed by connection as shown in fig. 1 can be connected in parallel to the single-component refrigerant circulation loop.
As an alternative implementation of the embodiment of the present invention, the mixed refrigerant circulation loop is filled with mixed refrigerant; the single-component refrigerant circulation loop is filled with single-component phase-change refrigerant. As an alternative implementation of the embodiment of the present invention, the mixed refrigerant includes a light component and a heavy component; the mass ratio of the light component to the heavy component is 5:5-3:7; the freezing point of the light component is lower than the liquefaction temperature of LNG, and the boiling point is higher than the liquefaction temperature of LNG; the boiling point of the heavy component at the working pressure is higher than the solidification temperature point of the single-component refrigerant; the boiling point of the single-component refrigerant is higher than the solidification temperature point of the secondary refrigerant at the working pressure. Wherein the boiling point of the light component is above 30 ℃ higher than the liquefaction temperature of LNG.
As an alternative to the embodiment of the invention, the light components comprise propane, ethylene and/or ethane; the heavy components comprise isobutane, R134A, R410A and/or R22; the single-component refrigerant comprises propane, ethylene and/or ethane, and the secondary refrigerant comprises CaCl2 water solution, naCl water solution and/or glycol water solution.
As an alternative implementation of the embodiment of the invention, the inlet temperature of the single-component refrigerant is between-8 and-12 ℃ and the outlet temperature is between-28 and-34 ℃.
As an alternative implementation of the embodiment of the invention, the recuperator 6 is a water-bath type recuperator.
As an alternative implementation of the embodiment of the invention, each heat exchanger is a shell-and-tube heat exchanger.
The following provides an LNG cold energy cascade control method using the LNG cold energy cascade system, including:
the cold energy recovery subsystem adopts a mixed refrigerant as a refrigerant in the refrigerant expansion power generation area, and adopts a single-component refrigerant as a refrigerant in the cold storage area and a refrigerant in the data center; after the LNG in the LNG storage tank and the mixed refrigerant are subjected to heat exchange and gasification, the LNG is subjected to heat exchange and temperature rise with the single-component refrigerant, and then is subjected to seawater reheating to 0 ℃ and then is sent to an output pipeline network;
the subsystem of the refrigerant expansion power generation area is that the mixed refrigerant is pressurized and heated by hot water, and then enters an expander to expand and do work, the expander drives a generator to operate to generate power, the mixed refrigerant is expanded and depressurized, the temperature is reduced, and the mixed refrigerant enters a mixed refrigerant storage tank to be recycled;
the cold storage area subsystem and the data center area subsystem are that the gaseous single-component refrigerant enters a heat exchanger to exchange heat with the low-temperature natural gas, the low-temperature liquid single-component refrigerant is divided into two parts, one part exchanges heat with the secondary refrigerant from the cold storage, the temperature rises to be gaseous, and then the next cycle is carried out; the second-stage refrigerant exchanges heat and then enters a refrigeration house for refrigeration, and after the temperature is raised, the second-stage refrigerant enters the next cycle; the other strand exchanges heat with the secondary refrigerant from the data center, the temperature rises to be gaseous, and then the next cycle is carried out; the second-stage refrigerant exchanges heat and then enters a data center for refrigeration, and after the temperature is raised, the second-stage refrigerant enters the next cycle.
As an alternative implementation of the embodiment of the present invention, the method further includes:
when the subsystem of the refrigerant expansion power generation area has abnormal working conditions, the second flow regulating valve, the sixth flow regulating valve and the eighth flow regulating valve are closed to cut off the mixed refrigerant circulation loop; increasing the opening of the eighth flow regulating valve to maintain the normal cooling of the data center and the refrigeration house; increasing the flow of LNG entering the original gasification pressure regulating system of the plant so as to maintain the normal gasification of the LNG;
when abnormal working conditions occur in the subsystem in the data center area, the seventh flow regulating valve is closed to stop the single-component refrigerant from entering the seventh heat exchanger to exchange heat with the secondary refrigerant; closing a ninth flow regulating valve to reduce the heat exchange amount of the single-component refrigerant circulation loop;
when the subsystem in the cold storage area has abnormal working conditions, the fifth flow regulating valve is closed to stop the single-component refrigerant from entering the eighth heat exchanger to exchange heat with the secondary refrigerant, and the ninth flow regulating valve is closed to reduce the heat exchange quantity of the single-component refrigerant circulation loop.
Specifically, the cold energy recovery subsystem comprises a mixed refrigerant serving as a refrigerant expansion power generation area refrigerant, a single-component refrigerant serving as a refrigerant reservoir area and a data center refrigerant, and the LNG in the LNG storage tank exchanges heat with the mixed refrigerant, is gasified, exchanges heat with the single-component refrigerant, heats the temperature to 0 ℃ through seawater, and is sent to an output pipeline network.
The subsystem of the refrigerant expansion power generation area is that the mixed refrigerant is pressurized and heated by hot water, and then enters an expander to expand and do work, the expander drives a generator to operate to generate power, the mixed refrigerant is expanded and depressurized, the temperature is reduced, and the mixed refrigerant enters a mixed refrigerant storage tank to be recycled next.
The cold storage area subsystem and the data center area subsystem are that the gaseous single-component refrigerant enters the heat exchanger to exchange heat with the low-temperature natural gas, the low-temperature liquid single-component refrigerant is divided into two parts, one part exchanges heat with the secondary refrigerant from the cold storage, the temperature rises to be gaseous, and then the next cycle is carried out. The second-stage refrigerant exchanges heat and then enters a refrigeration house for refrigeration, and after the temperature is raised, the second-stage refrigerant enters the next cycle; the other strand exchanges heat with the secondary refrigerant from the data center, the temperature rises to be gaseous, and then the next cycle is carried out. The second-stage refrigerant exchanges heat and then enters a data center for refrigeration, and after the temperature is raised, the second-stage refrigerant enters the next cycle.
When the subsystem of the refrigerant expansion power generation area has abnormal working conditions, only the second flow regulating valve 2, the sixth flow regulating valve 18 and the eighth flow regulating valve 25 are required to be closed to cut off the mixed refrigerant circulation loop; increasing the opening of the eighth flow regulating valve 25 to maintain normal cooling of the data center and the refrigerator; the LNG flow entering the original gasification pressure regulating system of the factory station is increased to maintain the normal gasification of LNG, and the normal operation of the LNG gasification station, the refrigeration house and the data center can be ensured.
When the subsystem in the data center area has abnormal working conditions, only the seventh flow regulating valve 23 is closed to stop the single-component refrigerant from entering the seventh heat exchanger 24 to exchange heat with the secondary refrigerant; and the ninth flow regulating valve 7 is closed to reduce the heat exchange amount of the single-component refrigerant circulation loop, so that the normal operation of the refrigeration house and the cold energy power generation area can be ensured.
When the subsystem in the cold storage area has abnormal working conditions, the fifth flow regulating valve 28 is only required to be closed to stop the single-component refrigerant from entering the eighth heat exchanger 29 to exchange heat with the secondary refrigerant, and the ninth flow regulating valve 7 is required to be closed to reduce the heat exchange quantity of the single-component refrigerant circulation loop, so that the normal operation of the data center and the cold energy power generation area can be ensured.
As an alternative to the embodiment of the invention, the cold energy recovery subsystem is upstream of the primary gasification facility. As shown in fig. 1, the system further includes: an open rack gasifier; the open frame gasifier is connected between the high-pressure output main pipe and the natural gas output main pipe. May further include: a voltage regulating subsystem; the first end of the pressure regulating subsystem is connected with the natural gas output main pipe, and the second end of the pressure regulating subsystem is connected with the second end of the reheater. May further include: a metering subsystem; the first end of the metering subsystem is connected with the voltage regulating subsystem.
Therefore, according to the LNG cold energy cascade utilization system and the control method, when an abnormal working condition occurs in one process of the refrigerant expansion power generation subsystem, the refrigeration house area subsystem and the data center area subsystem, other areas are not affected to continue production, and other cold energy cascade processes can stop due to the abnormal working condition of one process. Therefore, the efficient LNG cold energy cascade utilization is realized, the temperature utilization range is wide, the relative independence of each process section of the LNG cold energy cascade utilization is improved, the operation elasticity and fault tolerance of the whole project are improved, the economic influence caused by faults is reduced, the safe production can be realized, the operation cost is reduced, the whole project is environment-friendly, the potential safety hazard is reduced to the minimum, and the implementation of other projects of a station is not influenced.
Compared with the prior art and the current situation, the invention has the following beneficial effects:
1. LNG cold energy is used in combination of cold energy power generation, refrigeration houses and data centers, excellent cascade utilization performance is shown, and the cold energy utilization rate is high.
2. The same refrigerant is used in the whole loop formed by the process of the data center area and the process of the refrigeration house area, so that the whole device is simple to operate, convenient to maintain and good in safety.
3. For the LNG cold energy cascade utilization system, when an abnormal working condition occurs in a certain working section, the whole process is stopped. However, the method for cooling the data center and the refrigeration house by using the same single-component refrigerant well solves the problem. When the production is stopped due to the abnormal working condition of one of the cold energy power generation area, the data center or the refrigeration house area, the production of other areas is not affected.
In the following, an LNG vaporization station is taken as an example, and the refrigeration capacity is recycled, wherein the LNG vaporization scale of the LNG vaporization station is 500×104t/a, the vaporization flow rate is 200-560 t/h, the pre-vaporization temperature is-120 to-129 ℃, and the vaporization pressure is 8MPa. The pressure in the LNG storage tank is 4MPa. The LNG flow rate intended for this cold energy utilization process is 114t/h.
The LNG cold energy cascade utilization system is connected with the original gasification pressure regulating process in a parallel mode.
LNG used for the cold energy utilization process flow is gasified through the shell-and-tube heat exchanger, and then is heated through the water bath type reheater, and is converged with the original pressure regulating pipeline.
After the corresponding process equipment is installed, the embodiment mixes and injects ethane and propane into a mixed refrigerant circulation loop according to the mass ratio of 5:5 to be used as a mixed refrigerant (C2C 3), wherein the mass flow is 110t/h; injecting propane into the single-component refrigerant circulation loop to serve as a single-component refrigerant (C3), wherein the mass flow is 62t/h; and (3) applying the CaCl2 water solution as a secondary refrigerant to a cold storage area and a data center area, wherein the mass flow is 320t/h and 650t/h respectively.
When the equipment works normally, LNG with the flow rate of 114t/h at the temperature of minus 162 ℃ of 0.4MPa from an LNG storage tank is pressurized to 8MPa by a booster pump, the temperature is raised to minus 159 ℃, the LNG is divided into two paths, one path sequentially enters a first heat exchanger, the second heat exchanger respectively exchanges heat and gasifies with a C2C3 refrigerant, the other path enters a third heat exchanger to exchange heat and gasify with the C3 refrigerant, and after two gas-state natural gases are converged, the two gas-state natural gases are heated to 0 ℃ by a water bath type reheater and then are sent to an output pipeline network.
The temperature of the gaseous C2C3 refrigerant at the temperature of 0.2MPa and minus 19 ℃ is reduced to minus 61 ℃ and liquefied after the gaseous C2C3 refrigerant enters the first heat exchanger to exchange heat with the pressurized low-temperature natural gas, the low-temperature liquid C2C3 refrigerant is pressurized to 1.1MPa by a pressurizing pump, the temperature is divided into two parts after being increased to minus 60 ℃, one part enters the fourth heat exchanger, the other part enters the sixth heat exchanger to exchange heat with the gaseous C3 refrigerant from the data center and the refrigeration house respectively, the temperature of the liquid C2C3 refrigerant is increased to minus 24 ℃, then enters the fifth heat exchanger to be heated to 60 ℃ by normal pressure and hot water at the temperature of 70 ℃ and gasified, and then enters an expansion generator to be expanded to generate electricity, the temperature is reduced to minus 19 ℃, and then the C2C3 enters the first heat exchanger to the next circulation.
The low-temperature liquid C3 refrigerant with the pressure of 0.2MPa and the temperature of minus 32 ℃ from the C3 refrigerant storage tank is divided into two streams, wherein one stream enters an eighth heat exchanger to exchange heat with 30wt% CaCl2 water solution with the temperature of minus 5 ℃ from a refrigeration house, then the temperature rises to minus 10 ℃ and is gasified, and the other stream enters the seventh heat exchanger to exchange heat with 30wt% CaCl2 water solution with the temperature of 12 ℃ from a data center, then the temperature rises to minus 10 ℃ and is gasified; the gaseous C3 refrigerant after heat exchange in the data center is divided into two streams, one stream enters a sixth heat exchanger to exchange heat with the low-temperature C2C3 refrigerant of 1.1MPa and minus 60 ℃ after being pressurized by a second mixed refrigerant pressurizing pump, and the temperature is reduced to minus 32 ℃ and liquefied; the second strand is divided into 3 strands after being converged with the gaseous C3 refrigerant from the refrigeration house; one enters the second heat exchanger to exchange heat with the low-temperature natural gas from the first heat exchanger, and the other enters the third heat exchanger to exchange heat with the low-temperature natural gas, and the temperature is reduced and liquefied and then enters the C3 refrigerant storage tank. The third strand enters a fourth heat exchanger, exchanges heat with a low-temperature C2C3 refrigerant of 1.1MPa and minus 60 ℃ pressurized by a second mixed refrigerant pressurizing pump, and is converged with a liquid C3 refrigerant from a C3 refrigerant storage tank after temperature reduction and liquefaction, and enters the next cycle.
30wt% CaCl2 water solution from the cold storage, wherein the pressure is 0.1013MPa (normal pressure), the temperature is-5 ℃, the temperature is reduced to-20 ℃ after entering an eighth heat exchanger to exchange heat with C3, the cold storage is used for refrigerating, and the temperature of the CaCl2 water solution after the refrigerating is increased to-5 ℃ and enters the next cycle; 30wt% CaCl2 water solution from the data center has the pressure of 0.1013MPa (normal pressure) and the temperature of 12 ℃, enters a seventh heat exchanger to exchange heat with C3, then the temperature is reduced to 5 ℃, enters the data center to refrigerate, and after the refrigeration, the CaCl2 water solution temperature is up to 12 ℃ and enters the next cycle.
When the expansion power generation process is in abnormal working condition and needs to be stopped, only the second flow regulating valve, the sixth flow regulating valve and the eighth flow regulating valve are required to be closed so as to stop the operation of the C2C3 refrigerant circulation loop; meanwhile, the LNG flow entering the original gasification pressure regulating system of the factory station is increased to maintain the normal gasification of LNG, and the normal operation of the LNG gasification station, the refrigeration house and the data center can be ensured. At the moment, the gaseous C3 from the data center does not enter the sixth heat exchanger to exchange heat and liquefy with the C2C3 refrigerant, but directly merges with the gaseous C3 from the cold storage area, and enters the third heat exchanger to exchange heat with the LNG. In addition, as the flow of the gaseous C3 entering the third heat exchanger is increased, the opening of the eighth flow regulating valve is required to be increased so as to maintain the normal cooling of the data center and the refrigeration house; therefore, although the cold energy power generation area stops producing, the C3 refrigerant can still provide cold energy for the refrigeration house and the data center, and the normal operation of other areas is ensured.
When abnormal working conditions occur in the process of the data center area, only the seventh flow regulating valve is required to be closed so as to stop the single-component refrigerant from entering the seventh heat exchanger to exchange heat with the secondary refrigerant; and closing the ninth flow regulating valve to reduce the heat exchange amount of the single-component refrigerant circulation loop, so that the normal operation of the refrigeration house and the cold energy power generation area can be ensured. At this time, the liquid C3 refrigerant is not split, and is entirely sent to the cold storage area to exchange heat with the brine.
When the abnormal working condition occurs in the cold storage area, the fifth flow regulating valve is only required to be closed to stop the single-component refrigerant from entering the eighth heat exchanger to exchange heat with the second-stage refrigerant, and the ninth flow regulating valve is required to be closed to reduce the heat exchange quantity of the single-component refrigerant circulation loop, so that the normal operation of the data center and the cold energy power generation area can be ensured.
In summary, the embodiment of the invention provides a device for reducing the operation cost and having simple operation. By using the mixed refrigerant as the refrigerant of the expansion power generation circulation pipeline, the single-component refrigerant is used as the refrigerant of the refrigeration house area process and the data center area process, the temperature utilization range is wide, and the efficient gradient utilization of cold energy is realized. The system can reduce the overall investment of materials, improve the automation degree of projects, and does not increase new potential safety hazards. According to the embodiment, different fault conditions of the expansion power generation area, the data center area and the cold store area are set, and the production of other areas is not affected when the abnormal working condition of one area needs to be stopped through different adjustment modes. The relative independence of each process section of LNG cold energy cascade utilization is improved, the operation elasticity and fault tolerance of the whole project are improved, and the economic influence caused by faults is reduced. Meanwhile, the embodiments are simple and easy to implement, and can be suitable for the vast range of projects of LNG cold energy utilization at present.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
In one typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory.
The memory may include volatile memory in a computer-readable medium, random Access Memory (RAM) and/or nonvolatile memory, etc., such as Read Only Memory (ROM) or flash RAM. Memory is an example of a computer-readable medium.
Computer readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of storage media for a computer include, but are not limited to, phase change memory (PRAM), static Random Access Memory (SRAM), dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), read Only Memory (ROM), electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium, which can be used to store information that can be accessed by a computing device. Computer-readable media, as defined herein, does not include transitory computer-readable media (transmission media), such as modulated data signals and carrier waves.
The foregoing is merely exemplary of the present application and is not intended to limit the present application. Various modifications and changes may be made to the present application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. which are within the spirit and principles of the present application are intended to be included within the scope of the claims of the present application.
Claims (10)
1. An LNG cold energy cascade utilization system, comprising:
the system comprises a cold energy recovery subsystem, a refrigerant expansion power generation area subsystem, a refrigeration house area subsystem and a data center area subsystem; wherein:
the cold energy recovery subsystem includes: the LNG storage tank is connected with the first end of a first flow regulating valve (1) through a high-pressure output main pipe, the second end of the first flow regulating valve (1) is connected with the first end of a second flow regulating valve (2), the second end of the second flow regulating valve (2) is connected with the first end of a first heat exchanger (3), the second end of the first heat exchanger (3) is connected with the first end of a third flow regulating valve (5), the second end of the first heat exchanger (3) is connected with the first end of a second heat exchanger (4), the second end of the second heat exchanger (4) is connected with the first end of a third flow regulating valve (5), the second end of the first flow regulating valve (1) is connected with the first end of a fourth flow regulating valve (9), the third end of the fourth flow regulating valve (9) is connected with the first end of a third heat exchanger (8), the second end of the third heat exchanger (8) is connected with the first end of the third heat exchanger (5), the third end of the third heat exchanger (7) is connected with the third end of the third heat exchanger (7), the second end of the reheater (6) is connected with a natural gas output main pipe;
The refrigerant expansion power generation zone subsystem comprises: the mixed refrigerant circulation loop and with mixed refrigerant storage tank (11), first mixed refrigerant force (forcing) pump (12) and first three-way valve (13) of mixed refrigerant circulation loop parallelly connected, wherein, mixed refrigerant circulation loop includes: the first end of a second mixed refrigerant pressurizing pump (14) is connected with the third end of the first heat exchanger (3), the second end of the second mixed refrigerant pressurizing pump (14) is connected with the first end of a fourth heat exchanger (15), the second end of the fourth heat exchanger (15) is connected with the first end of a fifth heat exchanger (16), the second end of the fifth heat exchanger (16) is connected with the first end of an expander (17), the second end of the expander (17) is connected with the fourth end of the first heat exchanger (3), the third end of the expander (17) is connected with the first end of a generator (10), the second end of the generator (10) is connected with a power supply port, the first end of a sixth flow regulating valve (18) is connected with the third end of the third heat exchanger (8), the second end of the sixth flow regulating valve (18) is connected with the third end of the fourth heat exchanger (15), and the fourth end of the fourth heat exchanger (15) is connected with the fourth end of the fourth heat exchanger (8); the first end of the first three-way valve (13) is connected with the third end of the first heat exchanger (3), the second end of the first three-way valve (13) is connected with the first end of the mixed refrigerant storage tank (11), the second end of the mixed refrigerant storage tank (11) is connected with the first end of the first mixed refrigerant pressurizing pump (12), the second end of the first mixed refrigerant pressurizing pump (12) is connected with the third end of the first three-way valve (13), and the third end of the first three-way valve (13) is connected with the first end of the second mixed refrigerant pressurizing pump (14);
The cold storage area subsystem comprises: a single-component refrigerant circulation loop, the single-component refrigerant circulation loop comprising: the first end of the first single-component refrigerant pressurizing pump (27) is connected with the fourth end of the third heat exchanger (8), the second end of the first single-component refrigerant pressurizing pump (27) is connected with the first end of the fifth flow regulating valve (28), the second end of the fifth flow regulating valve (28) is connected with the first end of the eighth heat exchanger (29), the second end of the eighth heat exchanger (29) is connected with the third end of the third heat exchanger (8), and the third end of the eighth heat exchanger (29) and the fourth end of the eighth heat exchanger (29) are connected with a cold storage area;
the data center zone subsystem includes: the first end of the second three-way valve (21) is connected with the fourth end of the third heat exchanger (8), the second end of the second three-way valve (21) is connected with the first end of the single-component refrigerant storage tank (19), the second end of the single-component refrigerant storage tank (19) is connected with the first end of the second single-component refrigerant pressurizing pump (20), the second end of the second single-component refrigerant pressurizing pump (20) is connected with the third end of the second three-way valve (21), the third end of the second three-way valve (21) is connected with the first end of the sixth heat exchanger (26), the second end of the sixth heat exchanger (26) is connected with the first end of the eighth flow regulating valve (25), the second end of the eighth flow regulating valve (25) is connected with the third end of the third heat exchanger (8), the third end of the third single-component refrigerant pressurizing pump (20) is connected with the first end of the third single-component refrigerant pressurizing pump (22), the third end of the third single-component refrigerant pressurizing pump (22) is connected with the third end of the seventh heat exchanger (24), the third end of the seventh heat exchanger (24) is connected with the third end of the seventh heat exchanger (24), and the third end of the seventh heat exchanger is connected with the third end of the seventh heat exchanger (24).
2. The system of claim 1, wherein the mixed refrigerant circulation circuit is filled with a mixed refrigerant; and a single-component phase-change refrigerant is filled in the single-component refrigerant circulation loop.
3. The system of claim 2, wherein the mixed refrigerant comprises a light component and a heavy component; the mass ratio of the light component to the heavy component is 5:5-3:7; the freezing point of the light component is lower than the liquefaction temperature of LNG, and the boiling point of the light component is higher than the liquefaction temperature of LNG; the boiling point of the heavy component is higher than the solidification temperature point of the single-component refrigerant at the working pressure; the boiling point of the single-component refrigerant is higher than the solidification temperature point of the secondary refrigerant at the working pressure.
4. A system according to claim 3, wherein the light component has a boiling point above 30 ℃ above the liquefaction temperature of LNG.
5. A system according to claim 3, wherein the light components comprise propane, ethylene and/or ethane; the recombinant comprises isobutane, R134A, R410A and/or R22; the single-component refrigerant comprises propane, ethylene and/or ethane, and the secondary refrigerant comprises CaCl2 aqueous solution, naCl aqueous solution and/or glycol aqueous solution.
6. The system of claim 2, wherein the single component refrigerant inlet temperature is-8 to-12 ℃ and the outlet temperature is-28 to-34 ℃.
7. The system according to claim 1, characterized in that the recuperator (6) is a water bath type recuperator.
8. The system of claim 1, wherein each heat exchanger is a shell-and-tube heat exchanger.
9. An LNG cold energy cascade utilization control method using the LNG cold energy cascade utilization system of any one of claims 1 to 8, comprising:
the cold energy recovery subsystem adopts a mixed refrigerant as a refrigerant of the refrigerant expansion power generation area, and adopts a single-component refrigerant as a refrigerant of the cold storage area and a refrigerant of the data center; after the LNG in the LNG storage tank and the mixed refrigerant are subjected to heat exchange and gasification, the LNG is subjected to heat exchange and temperature rise with the single-component refrigerant, and then is subjected to seawater reheating to 0 ℃ and then is sent to an output pipeline network;
the subsystem of the refrigerant expansion power generation area is that the mixed refrigerant enters an expander to expand and do work after being pressurized and heated by hot water, the expander drives a generator to operate to generate power, the mixed refrigerant expands and reduces pressure, the temperature is reduced, and the mixed refrigerant enters a mixed refrigerant storage tank to the next cycle;
the cold storage area subsystem and the data center area subsystem are characterized in that a gaseous single-component refrigerant enters a heat exchanger to exchange heat with low-temperature natural gas, the low-temperature liquid single-component refrigerant is divided into two parts, one part exchanges heat with a secondary refrigerant from the cold storage, the temperature rises to be gaseous, and then the next cycle is performed; the second-stage refrigerant exchanges heat and then enters a refrigeration house for refrigeration, and after the temperature is raised, the second-stage refrigerant enters the next cycle; the other strand exchanges heat with the secondary refrigerant from the data center, the temperature rises to be gaseous, and then the next cycle is carried out; the second-stage refrigerant exchanges heat and then enters a data center for refrigeration, and after the temperature is raised, the second-stage refrigerant enters the next cycle.
10. The method as recited in claim 9, further comprising:
when the subsystem of the refrigerant expansion power generation area has abnormal working conditions, the second flow regulating valve, the sixth flow regulating valve and the eighth flow regulating valve are closed to cut off the mixed refrigerant circulation loop; increasing the opening of the eighth flow regulating valve to maintain the normal cooling of the data center and the refrigeration house; increasing the flow of LNG entering the original gasification pressure regulating system of the plant so as to maintain the normal gasification of the LNG;
when abnormal working conditions occur in the subsystem in the data center area, closing a seventh flow regulating valve to stop the single-component refrigerant from entering the seventh heat exchanger to exchange heat with the secondary refrigerant; closing a ninth flow regulating valve to reduce the heat exchange amount of the single-component refrigerant circulation loop;
when the abnormal working condition occurs in the subsystem in the cold storage area, the fifth flow regulating valve is closed to stop the single-component refrigerant from entering the eighth heat exchanger to exchange heat with the secondary refrigerant, and the ninth flow regulating valve is closed to reduce the heat exchange quantity of the single-component refrigerant circulation loop.
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| CN112629069A (en) * | 2020-12-10 | 2021-04-09 | 华南理工大学 | Multi-energy complementary LNG cold energy integrated utilization process and device |
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