CN111637686A - LNG cold energy air separation device and method for improving liquid nitrogen energy production - Google Patents
LNG cold energy air separation device and method for improving liquid nitrogen energy production Download PDFInfo
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- CN111637686A CN111637686A CN202010613879.2A CN202010613879A CN111637686A CN 111637686 A CN111637686 A CN 111637686A CN 202010613879 A CN202010613879 A CN 202010613879A CN 111637686 A CN111637686 A CN 111637686A
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- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
- F25J3/04048—Providing pressurised feed air or process streams within or from the air fractionation unit by compression of cold gaseous streams, e.g. intermediate or oxygen enriched (waste) streams
- F25J3/0406—Providing pressurised feed air or process streams within or from the air fractionation unit by compression of cold gaseous streams, e.g. intermediate or oxygen enriched (waste) streams of nitrogen
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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
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
- F25J3/04254—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using the cold stored in external cryogenic fluids
- F25J3/0426—The cryogenic component does not participate in the fractionation
- F25J3/04266—The cryogenic component does not participate in the fractionation and being liquefied hydrocarbons
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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
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
- F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
- F25J3/04218—Parallel arrangement of the main heat exchange line in cores having different functions, e.g. in low pressure and high pressure cores
- F25J3/04224—Cores associated with a liquefaction or refrigeration cycle
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- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
- F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
- F25J3/0423—Subcooling of liquid process streams
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- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
- F25J3/04254—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using the cold stored in external cryogenic fluids
- F25J3/0426—The cryogenic component does not participate in the fractionation
- F25J3/04266—The cryogenic component does not participate in the fractionation and being liquefied hydrocarbons
- F25J3/04272—The cryogenic component does not participate in the fractionation and being liquefied hydrocarbons and comprising means for reducing the risk of pollution of hydrocarbons into the air fractionation
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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
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
- F25J3/04333—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)streams
- F25J3/04351—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)streams of nitrogen
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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
- F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
- F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
- F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
- F25J3/04406—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system
- F25J3/04412—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system in a classical double column flowsheet, i.e. with thermal coupling by a main reboiler-condenser in the bottom of low pressure respectively top of high pressure column
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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
- F25J2215/00—Processes characterised by the type or other details of the product stream
- F25J2215/42—Nitrogen or special cases, e.g. multiple or low purity N2
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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
- F25J2250/00—Details related to the use of reboiler-condensers
- F25J2250/02—Bath type boiler-condenser using thermo-siphon effect, e.g. with natural or forced circulation or pool boiling, i.e. core-in-kettle heat exchanger
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- 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
- F25J2250/00—Details related to the use of reboiler-condensers
- F25J2250/20—Boiler-condenser with multiple exchanger cores in parallel or with multiple re-boiling or condensing streams
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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
- F25J2270/02—Internal refrigeration with liquid vaporising loop
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- Separation By Low-Temperature Treatments (AREA)
Abstract
The invention provides an LNG cold energy air separation device and method for improving liquid nitrogen energy production, which can liquefy, separate and purify oxygen and nitrogen by arranging an LNG cold box, a main heat exchanger cold box, a main tower cold box, a low-pressure nitrogen press and a circulating nitrogen press, can supplement low-pressure nitrogen into circulating nitrogen in the air separation process so as to ensure the extraction rate of oxygen and argon and improve the yield of liquid nitrogen, and can reduce the unit energy consumption of air separation operation, is particularly suitable for areas with less oxygen demand and more nitrogen demand, and further reduces the influence on the liquid air and liquid nitrogen temperature of an upper tower by independently arranging a liquid nitrogen product subcooler so as to reduce the influence on the rectification of the upper tower and increase the raw materials for producing liquid nitrogen by recycling the low-pressure nitrogen, thereby realizing the high oxygen extraction rate, high nitrogen separation rate and high nitrogen separation rate of the LNG cold energy, High nitrogen-oxygen yield ratio, flexible product regulation and low energy consumption.
Description
Technical Field
The invention relates to the technical field of air separation processes, in particular to an LNG cold energy air separation device and method for improving liquid nitrogen energy production.
Background
At present, LNG cold energy air separation has been widely popularized and applied as a utilization mode of LNG cold energy, and has become a preferred cold energy utilization project of an LNG receiving station due to the characteristics of low energy consumption and high profit. With the increase of the number of LNG receiving stations and the requirement of cold energy utilization projects, the LNG cold energy air separation technology is further popularized.
The main products of LNG cold energy air separation comprise liquid oxygen, liquid nitrogen and liquid argon, and the production scale and the product structure of the LNG cold energy air separation are influenced by the surrounding liquid market. Generally, heavy industrial areas have a higher demand for liquid oxygen and a lower demand for liquid nitrogen, whereas light industrial areas have a lower demand for liquid oxygen and a higher demand for liquid nitrogen. The existing LNG cold energy air separation plant has high oxygen extraction rate and low nitrogen extraction rate, can meet the requirements of heavy industrial areas, but cannot meet the requirements of light industrial areas. Therefore, an LNG cold energy air separation device and method which are high in oxygen extraction rate, large in nitrogen-oxygen yield ratio, flexible in product adjustment and low in energy consumption are urgently needed.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides an LNG cold energy air separation device and a method for improving the liquid nitrogen energy production, the LNG cold energy air separation device and the method carry out liquefaction, separation and purification of oxygen and nitrogen on air by arranging an LNG cold box, a main heat exchanger cold box, a main tower cold box, a low-pressure nitrogen compressor and a circulating nitrogen compressor, the LNG cold energy air separation device and the method can supplement the low-pressure nitrogen into the circulating nitrogen in the air separation process so as to ensure the extraction rate of the oxygen and the argon and improve the yield of the liquid nitrogen, simultaneously can reduce the unit energy consumption of air separation operation, are particularly suitable for areas with less oxygen demand and more nitrogen demand, in addition, the LNG cold energy device and the method reduce the influence on the liquid air and the liquid nitrogen temperature of an upper tower by independently arranging a liquid nitrogen product subcooler so as to reduce the influence on the rectification of the upper tower, and increase the raw materials for producing the liquid nitrogen by recycling the low-pressure nitrogen, thereby realizing the effects of high oxygen extraction rate, large nitrogen-oxygen yield ratio, flexible product adjustment and low energy consumption of LNG cold energy air separation.
The invention provides an LNG cold energy air separation device for improving the liquid nitrogen energy production, which has the following overall inventive concept:
the LNG cold energy air separation plant for improving the liquid nitrogen energy production comprises an LNG cold box, a main heat exchanger cold box, a main tower cold box, a low-pressure nitrogen compressor (NC 01) and a circulating nitrogen compressor (NC 02); wherein the content of the first and second substances,
the LNG cold box is connected with the main tower cold box through a circulating liquid nitrogen pipeline;
the main tower cold box is connected with the main heat exchanger cold box through a purified air pipeline, a circulating nitrogen pipeline, a low-pressure nitrogen pipeline and a sewage nitrogen pipeline;
the main heat exchanger cold box is connected with the LNG cold box through the circulating nitrogen pipeline;
the low-pressure nitrogen compressor (NC 01) is respectively connected with the main heat exchanger cold box and the LNG cold box through the low-pressure nitrogen pipeline;
the circulating nitrogen press (NC 02) is connected with the LNG cold box through the circulating nitrogen pipeline;
in one embodiment disclosed herein, the LNG cold box comprises an LNG heat exchanger (E01) and a liquid nitrogen subcooler (E02); wherein the content of the first and second substances,
the LNG heat exchanger (E01) is respectively connected with the main heat exchanger cold box and the circulating nitrogen press (NC 02) through the circulating nitrogen pipeline and is used for cooling circulating nitrogen;
the liquid nitrogen subcooler (E02) is connected with the main tower cold box through the circulating nitrogen pipeline and is connected with the LNG heat exchanger (E01) and is used for subcooling circulating liquid nitrogen;
in one embodiment of the present disclosure, the primary heat exchanger cold box comprises a primary heat exchanger (E03); wherein the content of the first and second substances,
the main heat exchanger (E03) is connected with the LNG cold box through the circulating nitrogen pipeline and is connected with the low-pressure nitrogen press (NC 01) through the low-pressure nitrogen pipeline;
the main heat exchanger (E03) is used for reheating circulating nitrogen from the LNG cold box;
in one embodiment disclosed herein, the main column cold box comprises a liquid nitrogen-nitrogen heat exchanger (E04), a liquid nitrogen subcooler (E05), a liquid air liquid nitrogen subcooler (E06), a lower column (C01), an upper column (C02), a main condenser evaporator (K01), and a liquid nitrogen knockout drum (V01); wherein the content of the first and second substances,
the lower tower (C01) is respectively connected with the main condensation evaporator (K01), the liquid nitrogen-nitrogen heat exchanger (E04) and the liquid air liquid nitrogen subcooler (E06) through pipelines;
the upper tower (C02) is respectively connected with the liquid nitrogen subcooler (E05) and the liquid air liquid nitrogen subcooler (E06) through pipelines;
the liquid nitrogen separation tank (V01) is respectively connected with the liquid nitrogen subcooler (E05) and the liquid air liquid nitrogen subcooler (E06) through pipelines;
in one embodiment disclosed herein, the low pressure nitrogen press (NC 01) is configured to pressurize the low pressure nitrogen from the upper column (C02) of the main column cold box before delivering the pressurized low pressure nitrogen to the recycle nitrogen line;
the cycle nitrogen press (NC 02) is used to pressurize nitrogen from the cycle nitrogen line.
Based on the same inventive concept, the invention also provides an LNG cold energy air separation method for improving the liquid nitrogen energy production, and the LNG cold energy air separation method comprises the following steps:
the LNG cold box provides the cold produced by LNG vaporization to the main heat exchanger cold box and the lower column (C01) to achieve liquefaction cooling of air or nitrogen;
said main heat exchanger cold box cooling the purified air before sending it to said lower column (C01);
the lower column (C01) rectifying, purifying and condensing the cooling air coming from the main heat exchanger cold box, thereby forming liquid nitrogen;
the liquid nitrogen is circularly transmitted among the LNG cold box, the main heat exchanger cold box and the liquid nitrogen-nitrogen heat exchanger (E04), so that the cold energy of LNG vaporization is transmitted, and meanwhile, part of liquid nitrogen products are obtained;
in one embodiment of the air separation method, the LNG cold energy air separation method further comprises the steps that purified air is cooled by a main heat exchanger (E03) and then sent to a lower tower (C01) for rectification, the lower tower (C01) divides nitrogen into a first stream and a second stream, the first stream of nitrogen enters a main condensation evaporator (K01) and is liquefied by the main condensation evaporator (K01), one part of the liquefied nitrogen is returned to the lower tower (C01) as reflux liquid, the other part of the liquefied nitrogen is sent to a liquid air liquid nitrogen subcooler (E06) and is returned to the upper tower (C02) as reflux liquid, the rest of the liquefied nitrogen is sent to a liquid nitrogen storage tank as a liquid nitrogen product, the second stream of nitrogen is sent to a liquid nitrogen-nitrogen heat exchanger (E04), is liquefied and then merged to the main condensation evaporator (K01) and is returned to the lower tower (C01) so as to provide cold energy and reflux liquid for the lower tower (C01), oxygen-enriched liquid air at the bottom of the lower tower (C01) is conveyed to a liquid air liquid nitrogen subcooler (E06), is cooled and then is conveyed to the upper tower (C02) to participate in rectification;
after the liquid oxygen at the bottom of the upper tower (C02) is evaporated and purified by a main condensing evaporator (K01), the liquid oxygen is used as a liquid oxygen product and is conveyed to a liquid air liquid nitrogen subcooler (E06) for subcooling, and then the liquid oxygen product is conveyed to a liquid oxygen storage tank of a main tower cold box for storage; the low-pressure nitrogen at the top of the upper tower (C02) is reheated by a liquid air liquid nitrogen subcooler (E06) and a main heat exchanger (E03) in sequence, then is conveyed to a low-pressure nitrogen compressor (NC 01) to be pressurized, and then is conveyed to a circulating nitrogen channel; waste nitrogen at the top of the upper tower (C02) is reheated by a liquid-air liquid nitrogen subcooler (E06) and a main heat exchanger (E03) in sequence and then is used as regeneration gas;
in one embodiment of the air separation process, the circulating liquid nitrogen from the LNG cold box is throttled to enter a liquid nitrogen knockout drum (V01) and is separated into a first and second stream by a liquid phase; the first stream is conveyed to a liquid nitrogen-nitrogen heat exchanger (E04) and exchanges heat with nitrogen from a lower tower (C01) to be vaporized, the vaporized first stream is converged to the top of a liquid nitrogen separation tank (V01) and enters a main heat exchanger (E03) in a gas phase mode, and the reheated first stream passing through the main heat exchanger (E03) returns to an LNG cold box as circulating nitrogen; the second strand is subcooled by a liquid nitrogen subcooler (E05) and then divided into a first part and a second part, the first part is used as a liquid nitrogen product and is conveyed to a liquid nitrogen storage tank for storage, the second part is throttled and then returns to the liquid nitrogen subcooler (E05), and the second part is subjected to reheating by the liquid nitrogen subcooler (E05), then is converged into a low-pressure nitrogen pipeline, and is conveyed to a main heat exchanger (E03) for reheating;
in one embodiment of the air separation method, circulating nitrogen from a cold box of a main heat exchanger is conveyed to an LNG heat exchanger (E01), is cooled to a preset temperature and then enters a first section of a circulating nitrogen compressor (NC 02) for pressurization, then enters an LNG heat exchanger (E01) again for cooling to a preset temperature and then enters a second section of the circulating nitrogen compressor (NC 02) for pressurization, enters an LNG heat exchanger for cooling (E01) for liquefaction, then enters a liquid nitrogen subcooler (E02) and is divided into a first strand, a second strand and a third strand, the first strand is used as circulating liquid nitrogen and conveyed to the cold box of the main tower to provide cold energy for the cold box of the main tower, the second strand meets a preset pressure after throttling and then returns to the liquid nitrogen subcooler (E02) and is reheated, then enters a heat exchanger (E01) for reheating to a preset temperature and then joins the circulating nitrogen to the circulating nitrogen and then enters the circulating nitrogen compressor (NC 02), the third strand meets another preset pressure after throttling and then returns to the liquid nitrogen subcooler (E02) and is reheated, the re-entering LNG heat exchanger (E01) is reheated to a preset temperature and then is merged into the circulating nitrogen to enter the circulating nitrogen compressor (NC 02);
in one embodiment of the air separation method, LNG from the LNG receiving station enters the LNG heat exchanger (E01) to be reheated by nitrogen to a predetermined temperature, a portion of which is sent to the LNG-glycol heat exchanger to provide refrigeration to the glycol solution, and then is reheated by the LNG-glycol heat exchanger and returned to the LNG receiving station, and another portion of which continues to be reheated by the LNG heat exchanger (E01) to a predetermined temperature and is directly returned to the LNG receiving station.
Compared with the prior art, the LNG cold energy air separation device and the method for improving the liquid nitrogen energy production of the invention have the advantages that the LNG cold energy air separation device and the method carry out liquefaction, separation and purification of oxygen and nitrogen on air by arranging the LNG cold box, the main heat exchanger cold box, the main tower cold box, the low-pressure nitrogen press and the circulating nitrogen press, the low-pressure nitrogen can be supplemented into the circulating nitrogen in the air separation process, so that the extraction rate of the oxygen and the argon is ensured, the yield of liquid nitrogen is improved, the unit energy consumption of air separation operation can be reduced, the LNG cold energy air separation device and the method are particularly suitable for areas with small oxygen demand and large nitrogen demand, in addition, the influence on the liquid air and the liquid nitrogen temperature of an upper tower is reduced by independently arranging the liquid nitrogen product subcooler, the influence on the rectification of the upper tower is reduced, the raw material for producing liquid nitrogen is increased by recycling the low-pressure nitrogen, and the extraction rate of the LNG cold energy air separation is, High nitrogen-oxygen yield ratio, flexible product regulation and low energy consumption.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the embodiments or technical descriptions will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an LNG cold energy air separation plant for improving liquid nitrogen energy production provided by the invention.
FIG. 2 is a flow chart of an LNG cold energy air separation method for improving liquid nitrogen energy production provided by the invention.
Fig. 3 is a comparison chart of capacity parameters of the LNG cold energy air separation plant for improving the capacity of liquid nitrogen provided by the invention.
Fig. 4 is a comparison chart of the equipment parameters of the LNG cold energy air separation plant for improving the liquid nitrogen energy production provided by the invention.
Reference numerals: 1. an LNG cold box; 2. a main heat exchanger cold box; 3. the main tower cold box.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, a schematic structural diagram of an LNG cold energy air separation plant and method for improving liquid nitrogen energy production provided by the present invention is shown. The LNG cold energy air separation device for improving the liquid nitrogen energy production comprises an LNG cold box 1, a main heat exchanger cold box 2, a main tower cold box 3, a low-pressure nitrogen compressor NC01 and a circulating nitrogen compressor NC 02; wherein the content of the first and second substances,
the LNG cold box 1 is connected with the main tower cold box 3 through a circulating liquid nitrogen pipeline;
the main tower cold box 3 is connected with the main heat exchanger cold box 2 through a purified air pipeline, a circulating nitrogen pipeline, a low-pressure nitrogen pipeline and a sewage nitrogen pipeline;
the main heat exchanger cold box 2 is connected with the LNG cold box 1 through the circulating nitrogen pipeline;
the low-pressure nitrogen compressor NC01 is respectively connected with the main heat exchanger cold box 2 and the LNG cold box 1 through the low-pressure nitrogen pipeline;
the circulating nitrogen compressor NC02 is connected to the LNG cold box 1 through the circulating nitrogen line.
Preferably, in one embodiment disclosed herein, the LNG cold box 1 includes an LNG heat exchanger E01 and a liquid nitrogen subcooler E02; wherein the content of the first and second substances,
the LNG heat exchanger E01 is connected to the main heat exchanger cold box 2 and the circulating nitrogen press NC02 through the circulating nitrogen pipeline, respectively, and is configured to cool the circulating nitrogen;
the liquid nitrogen subcooler E02 is connected to the main column cold box 3 through the circulating nitrogen gas pipe and to the LNG heat exchanger E01, which is used for subcooling of circulating liquid nitrogen.
Preferably, the main heat exchanger cold box 2 comprises a main heat exchanger E03; wherein the content of the first and second substances,
the main heat exchanger E03 is connected with the LNG cold box 1 through the circulating nitrogen pipeline and is connected with the low-pressure nitrogen press NC01 through the low-pressure nitrogen pipeline;
the primary heat exchanger E03 is used to reheat the circulating nitrogen from the LNG cold box 1.
Preferably, the main column cold box 3 comprises a liquid nitrogen-nitrogen heat exchanger E04, a liquid nitrogen subcooler E05, a liquid air liquid nitrogen subcooler E06, a lower column C01, an upper column C02, a main condensing evaporator K01 and a liquid nitrogen knockout drum V01; wherein the content of the first and second substances,
the lower tower C01 is respectively connected with the main condensation evaporator K01, the liquid nitrogen-nitrogen heat exchanger E04 and the liquid air liquid nitrogen subcooler E06 through pipelines;
the upper tower C02 is respectively connected with the liquid nitrogen subcooler E05 and the liquid air liquid nitrogen subcooler E06 through pipelines;
the liquid nitrogen separation tank V01 is respectively connected with the liquid nitrogen subcooler E05 and the liquid air liquid nitrogen subcooler E06 through pipelines.
Preferably, the low-pressure nitrogen press NC01 is configured to pressurize the low-pressure nitrogen from the upper column C02 of the main column cold box 3, and then to feed the pressurized low-pressure nitrogen to the circulating nitrogen pipeline;
the cycle nitrogen press NC02 was used to pressurize the nitrogen from the cycle nitrogen line.
Referring to fig. 2, a flow chart of an LNG cold energy air separation method for improving liquid nitrogen energy production provided by the present invention is shown. The LNG cold energy air separation method comprises the following steps:
the LNG cold box 1 provides the cold energy generated by LNG vaporization to the main heat exchanger cold box 2 and the lower column C01 to achieve liquefaction cooling of air or nitrogen;
the main heat exchanger cold box 2 cools the purified air and delivers it to the lower column C01;
the lower column C01 rectifies, purifies and condenses the cooling air coming from the main heat exchanger cold box 2, thereby forming liquid nitrogen;
the liquid nitrogen is circularly transmitted among the LNG cold box 1, the main heat exchanger cold box 2 and the liquid nitrogen-nitrogen heat exchanger E04, so that the cold energy of LNG vaporization is transferred, and meanwhile, part of liquid nitrogen products are obtained.
Preferably, the LNG cold energy air separation method also comprises the steps that after the purified air is cooled by a main heat exchanger E03, is sent into a lower tower C01 for rectification, the lower tower C01 divides nitrogen into a first strand and a second strand, wherein the first stream of nitrogen enters the main condensing evaporator K01 and is liquefied by the main condensing evaporator K01, wherein a part of the liquefied is returned as reflux to the lower column C01, another part of the liquefied is sent to a liquid air liquid nitrogen subcooler E06 and a part of the subcooled liquid is returned as reflux to the upper column C02, the remaining part of the subcooled liquid is sent as liquid nitrogen product to a liquid nitrogen storage tank for storage, the second part of nitrogen is delivered to a liquid nitrogen-nitrogen heat exchanger E04 to be liquefied and then is merged into a main condensing evaporator K01 to be refluxed to a lower tower C01, thereby providing cold and reflux for the lower tower C01, and conveying the oxygen-enriched liquid air at the bottom of the lower tower C01 to a liquid air liquid nitrogen subcooler E06, cooling and then conveying to the upper tower C02 for rectification;
liquid oxygen at the bottom of the upper tower C02 is evaporated and purified by a main condensing evaporator K01, then is transmitted to a liquid air liquid nitrogen subcooler E06 as a liquid oxygen product for subcooling, and then is transmitted to a liquid oxygen storage tank of a main tower cold box 3 for storage; the low-pressure nitrogen at the top of the upper tower C02 is reheated by a liquid air liquid nitrogen subcooler E06 and a main heat exchanger E03 in sequence, then is transmitted to a low-pressure nitrogen compressor NC01 to be pressurized, and then is transmitted to a circulating nitrogen channel; the waste nitrogen gas at the top of the upper tower C02 is reheated by a liquid air liquid nitrogen subcooler E06 and a main heat exchanger E03 in sequence and then is used as regeneration gas.
Preferably, the circulating liquid nitrogen from the LNG cold box 1 enters a liquid nitrogen separation tank V01 after being throttled, and is divided into a first strand and a second strand by a liquid phase; the first stream is conveyed to a liquid nitrogen-nitrogen heat exchanger E04 and exchanges heat with nitrogen from a lower tower C01 to be vaporized, the vaporized first stream is converged to the top of a liquid nitrogen separation tank V01 and enters a main heat exchanger E03 in a gas phase mode, and the heat recovered by the main heat exchanger E03 is used as circulating nitrogen to return to the LNG cold box 1; the second strand is subcooled by a liquid nitrogen subcooler E05 and then divided into a first part and a second part, the first part is used as a liquid nitrogen product and is conveyed to a liquid nitrogen storage tank for storage, the second part is throttled and then returns to the liquid nitrogen subcooler E05, and the second part is subjected to reheating by the liquid nitrogen subcooler E05, then is converged into a low-pressure nitrogen pipeline, and is conveyed to a main heat exchanger E03 for reheating.
Preferably, the circulating nitrogen from the main heat exchanger cold box 2 is transmitted to the LNG heat exchanger E01, is cooled to a predetermined temperature, enters a first section of the circulating nitrogen compressor NC02 for pressurization, enters the LNG heat exchanger E01 again for cooling to a predetermined temperature, enters a second section of the circulating nitrogen compressor NC02 for pressurization, enters the LNG heat exchanger cold E01 for liquefaction, enters the liquid nitrogen subcooler E02 and is divided into a first strand, a second strand and a third strand, the first strand is transmitted to the main tower cold box 3 as circulating liquid nitrogen to provide cold energy for the main tower cold box 3, the second strand meets a predetermined pressure after being throttled, returns to the liquid nitrogen subcooler E02 and is reheated, enters the LNG heat exchanger E01 for reheating to a predetermined temperature, is converged into the circulating nitrogen and then enters the circulating nitrogen compressor NC02, the third strand meets another predetermined pressure after being throttled, returns to the liquid nitrogen subcooler E02 and is reheated, and the re-entering LNG heat exchanger E01 is reheated to a preset temperature and then is merged into the circulating nitrogen to enter the circulating nitrogen compressor NC 02.
Preferably, after the LNG from the LNG receiving station enters the LNG heat exchanger E01 and is reheated to a predetermined temperature by nitrogen, a part of the LNG is transferred to the LNG-glycol heat exchanger to provide refrigeration for the glycol solution, and then is reheated by the LNG-glycol heat exchanger and returned to the LNG receiving station, and another part of the LNG is reheated to a predetermined temperature by the LNG heat exchanger E01 and directly returned to the LNG receiving station.
By arranging the liquid nitrogen subcooler E05 in the main cooling tower box 3, the subcooled liquid nitrogen product can be removed from the liquid air liquid nitrogen subcooler E06, so that the influence on the temperature of liquid air and liquid nitrogen of the upper tower C02 and the influence on the rectification process of the upper tower C02 are reduced; in addition, the liquid nitrogen subcooler E05 transmits the low-pressure nitrogen gas of the refluence to the main heat exchanger E03 for reheating and recycling, which effectively improves the nitrogen extraction rate and increases the yield of liquid nitrogen; also, the low pressure nitrogen from upper column C02, pressurized by low pressure nitrogen compressor NC01, was transferred into the circulating nitrogen line to provide a source of raw material for the production of liquid nitrogen product.
Referring to fig. 3 and 4, a capacity parameter comparison chart and a device parameter comparison chart between the LNG cold energy air separation plant for improving the liquid nitrogen capacity provided by the present invention and a conventional LNG cold energy air separation plant in the prior art are shown, respectively. This improve LNG cold energy air separation plant of liquid nitrogen energy production can realize liquid nitrogen output maximize. As can be seen from fig. 3 to 4, the LNG cold energy air separation plant of the present invention has higher advantages in both the capacity and the operation performance of the plant compared to the conventional LNG cold energy air separation plant, which are specifically shown as follows: firstly, under the same air scale, the LNG cold energy air separation device has the advantages of large liquid nitrogen capacity, large nitrogen-oxygen yield ratio and high extraction rate; secondly, the LNG cold energy air separation plant has low unit energy consumption which is 10 percent lower than that of the conventional LNG cold energy air separation plant; thirdly, the low-pressure nitrogen compressor of the LNG cold energy air separation device has higher working flexibility, and can adjust the yield of liquid nitrogen in a larger range; fourth, the LNG cold energy air separation plant of the present invention is capable of independent liquid nitrogen product subcooling configurations that have less impact on the operation of the rectification system during variable load operation.
From the content of the above embodiments, the LNG cold energy air separation device and method for improving liquid nitrogen energy production can maximize liquid nitrogen yield, separate and purify air by arranging an LNG cold box, a main heat exchanger cold box, a main tower cold box, a low pressure nitrogen compressor and a circulating nitrogen compressor, and produce liquid oxygen, liquid nitrogen and liquid argon, and simultaneously can supplement low pressure nitrogen to the circulating nitrogen in the air separation process, so as to ensure the extraction rate of oxygen and argon and improve the yield of liquid nitrogen, and can reduce the unit energy consumption of air separation operation, which is particularly suitable for areas with small oxygen demand and large nitrogen demand, and in addition, the LNG cold energy air separation device and method can reduce the influence on the temperature of liquid air and liquid nitrogen entering an upper tower by independently arranging a liquid nitrogen product subcooler, further reduce the influence on the rectification of the upper tower, and further increase the raw material for producing liquid nitrogen by recovering low pressure nitrogen, thereby realizing the effects of high oxygen extraction rate, large nitrogen-oxygen yield ratio, flexible product adjustment and low energy consumption of LNG cold energy air separation.
Claims (10)
1. Improve LNG cold energy air separation plant of liquid nitrogen energy production, its characterized in that:
the LNG cold energy air separation plant for improving the liquid nitrogen energy production comprises an LNG cold box, a main heat exchanger cold box, a main tower cold box, a low-pressure nitrogen compressor (NC 01) and a circulating nitrogen compressor (NC 02); wherein the content of the first and second substances,
the LNG cold box is connected with the main tower cold box through a circulating liquid nitrogen pipeline;
the main tower cold box is connected with the main heat exchanger cold box through a purified air pipeline, a circulating nitrogen pipeline, a low-pressure nitrogen pipeline and a sewage nitrogen pipeline;
the main heat exchanger cold box is connected with the LNG cold box through the circulating nitrogen pipeline;
the low-pressure nitrogen compressor (NC 01) is respectively connected with the main heat exchanger cold box and the LNG cold box through the low-pressure nitrogen pipeline;
the circulating nitrogen press (NC 02) is connected with the LNG cold box through the circulating nitrogen pipeline.
2. An LNG cold energy air separation plant for improving the energy production of liquid nitrogen according to claim 1, characterized in that:
the LNG cold box comprises an LNG heat exchanger (E01) and a liquid nitrogen subcooler (E02); wherein the content of the first and second substances,
the LNG heat exchanger (E01) is respectively connected with the main heat exchanger cold box and the circulating nitrogen press (NC 02) through the circulating nitrogen pipeline and is used for cooling circulating nitrogen;
the liquid nitrogen subcooler (E02) is connected with the main tower cold box through the circulating nitrogen pipeline and is connected with the LNG heat exchanger (E01), and the liquid nitrogen subcooler is used for subcooling circulating liquid nitrogen.
3. An LNG cold energy air separation plant for improving the energy production of liquid nitrogen according to claim 2, characterized in that:
the main heat exchanger cold box comprises a main heat exchanger (E03); wherein the content of the first and second substances,
the main heat exchanger (E03) is connected with the LNG cold box through the circulating nitrogen pipeline and is connected with the low-pressure nitrogen press (NC 01) through the low-pressure nitrogen pipeline;
the main heat exchanger (E03) is used for reheating circulating nitrogen from the LNG cold box.
4. An LNG cold energy air separation plant for improving the energy production of liquid nitrogen according to claim 3, characterized in that:
the main tower cold box comprises a liquid nitrogen-nitrogen heat exchanger (E04), a liquid nitrogen subcooler (E05), a liquid air liquid nitrogen subcooler (E06), a lower tower (C01), an upper tower (C02), a main condensing evaporator (K01) and a liquid nitrogen separation tank (V01); wherein the content of the first and second substances,
the lower tower (C01) is respectively connected with the main condensation evaporator (K01), the liquid nitrogen-nitrogen heat exchanger (E04) and the liquid air liquid nitrogen subcooler (E06) through pipelines;
the upper tower (C02) is respectively connected with the liquid nitrogen subcooler (E05) and the liquid air liquid nitrogen subcooler (E06) through pipelines;
the liquid nitrogen separation tank (V01) is respectively connected with the liquid nitrogen subcooler (E05) and the liquid air liquid nitrogen subcooler (E06) through pipelines.
5. An LNG cold energy air separation plant for improving the energy production of liquid nitrogen according to claim 4, characterized in that:
the low-pressure nitrogen press (NC 01) is used for pressurizing low-pressure nitrogen from an upper tower (C02) of the main tower cold box and then conveying the pressurized low-pressure nitrogen to the circulating nitrogen pipeline;
the cycle nitrogen press (NC 02) is used to pressurize nitrogen from the cycle nitrogen line.
6. An LNG cold energy air separation method based on the LNG cold energy air separation plant for improving the liquid nitrogen energy production of claim 5, wherein the LNG cold energy air separation method comprises the following steps:
the LNG cold box provides the cold produced by LNG vaporization to the main heat exchanger cold box and the lower column (C01) to achieve liquefaction cooling of air or nitrogen;
said main heat exchanger cold box cooling the purified air before sending it to said lower column (C01);
the lower column (C01) rectifying, purifying and condensing the cooling air coming from the main heat exchanger cold box, thereby forming liquid nitrogen;
and the liquid nitrogen is circularly transmitted among the LNG cold box, the main heat exchanger cold box and the liquid nitrogen-nitrogen heat exchanger (E04), so that the cold energy of LNG vaporization is transferred, and part of liquid nitrogen products are obtained at the same time.
7. An LNG cold energy air separation process according to claim 6, characterized in that:
the LNG cold energy air separation method further comprises the steps that purified air is cooled through a main heat exchanger (E03) and then sent into a lower tower (C01) to be rectified, the lower tower (C01) divides nitrogen into a first part and a second part, the first part of the nitrogen enters a main condensation evaporator (K01) and is liquefied through the main condensation evaporator (K01), one part of the liquefied nitrogen serves as reflux liquid and flows back to the lower tower (C01), the other part of the liquefied nitrogen is sent to a liquid air subcooler (E06), one part of the subcooled liquid nitrogen serves as reflux liquid and flows back to the upper tower (C02), the rest part of the subcooled liquid nitrogen serves as a liquid nitrogen product and is sent to a liquid nitrogen storage tank, the second part of the nitrogen is sent to a liquid nitrogen-nitrogen heat exchanger (E04), is liquefied and then merged to a main condensation evaporator (K01) and flows back to the lower tower (C01), and therefore cold energy and reflux liquid are provided for the lower tower (C01), oxygen-enriched liquid air at the bottom of the lower tower (C01) is conveyed to a liquid air liquid nitrogen subcooler (E06), is cooled and then is conveyed to the upper tower (C02) to participate in rectification;
after the liquid oxygen at the bottom of the upper tower (C02) is evaporated and purified by a main condensing evaporator (K01), the liquid oxygen is used as a liquid oxygen product and is conveyed to a liquid air liquid nitrogen subcooler (E06) for subcooling, and then the liquid oxygen product is conveyed to a liquid oxygen storage tank of a main tower cold box for storage; the low-pressure nitrogen at the top of the upper tower (C02) is reheated by a liquid air liquid nitrogen subcooler (E06) and a main heat exchanger (E03) in sequence, then is conveyed to a low-pressure nitrogen compressor (NC 01) to be pressurized, and then is conveyed to a circulating nitrogen channel; the waste nitrogen gas at the top of the upper tower (C02) is reheated by a liquid air liquid nitrogen subcooler (E06) and a main heat exchanger (E03) in sequence and then is used as regeneration gas.
8. An LNG cold energy air separation process according to claim 7, characterized in that:
circulating liquid nitrogen from an LNG cold box enters a liquid nitrogen separation tank (V01) after throttling, and is divided into a first strand and a second strand by a liquid phase; the first stream is conveyed to a liquid nitrogen-nitrogen heat exchanger (E04) and exchanges heat with nitrogen from a lower tower (C01) to be vaporized, the vaporized first stream is converged to the top of a liquid nitrogen separation tank (V01) and enters a main heat exchanger (E03) in a gas phase mode, and the reheated first stream passing through the main heat exchanger (E03) returns to an LNG cold box as circulating nitrogen; the second strand is divided into a first part and a second part after being subcooled by a liquid nitrogen subcooler (E05), the first part is used as a liquid nitrogen product and is conveyed to a liquid nitrogen storage tank for storage, the second part returns to the liquid nitrogen subcooler (E05) after being throttled, and is converged into a low-pressure nitrogen pipeline after being reheated by the liquid nitrogen subcooler (E05), and then is conveyed to a main heat exchanger (E03) for reheating.
9. An LNG cold energy air separation process according to claim 8, characterized in that:
circulating nitrogen from a cold box of a main heat exchanger is transmitted to an LNG heat exchanger (E01), is cooled to a preset temperature and then enters a first section of a circulating nitrogen compressor (NC 02) for pressurization, then enters an LNG heat exchanger (E01) again to be cooled to a preset temperature and then enters a second section of the circulating nitrogen compressor (NC 02) for pressurization, enters the LNG heat exchanger for cooling (E01) for liquefaction, then enters a liquid nitrogen subcooler (E02) and is divided into a first strand, a second strand and a third strand, the first strand is used as circulating liquid nitrogen and transmitted to the cold box of the main tower to provide cold energy for the cold box of the main tower, the second strand meets a preset pressure after throttling, then returns to the liquid nitrogen subcooler (E02) and is reheated, then enters the LNG heat exchanger (E01) to be reheated to a preset temperature and then is merged into the circulating nitrogen and then enters the circulating nitrogen compressor (NC 02), the third strand meets another preset pressure after throttling, then returns to the subcooler (E02) and is reheated, and the re-entering LNG heat exchanger (E01) is reheated to a preset temperature and then is merged into the circulating nitrogen to enter the circulating nitrogen compressor (NC 02).
10. An LNG cold energy air separation process according to claim 9, characterized in that:
after the LNG from the LNG receiving station enters the LNG heat exchanger (E01) and is reheated to a preset temperature by nitrogen, one part of the LNG is transmitted to the LNG-glycol heat exchanger to provide cold energy for the glycol solution, then the LNG is reheated by the LNG-glycol heat exchanger and returns to the LNG receiving station, and the other part of the LNG is reheated to a preset temperature by the LNG heat exchanger (E01) and directly returns to the LNG receiving station.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113587552A (en) * | 2021-07-14 | 2021-11-02 | 四川空分设备(集团)有限责任公司 | Air separation system and air separation method utilizing LNG cold energy |
| CN113587551A (en) * | 2021-07-14 | 2021-11-02 | 四川空分设备(集团)有限责任公司 | Air separation system and method for producing liquid oxygen, liquid nitrogen and liquid argon by using LNG cold energy |
| CN114017992A (en) * | 2021-11-09 | 2022-02-08 | 四川空分设备(集团)有限责任公司 | Air separation system suitable for LNG cold energy load changes |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113587552A (en) * | 2021-07-14 | 2021-11-02 | 四川空分设备(集团)有限责任公司 | Air separation system and air separation method utilizing LNG cold energy |
| CN113587551A (en) * | 2021-07-14 | 2021-11-02 | 四川空分设备(集团)有限责任公司 | Air separation system and method for producing liquid oxygen, liquid nitrogen and liquid argon by using LNG cold energy |
| CN113587552B (en) * | 2021-07-14 | 2022-11-18 | 四川空分设备(集团)有限责任公司 | Air separation system and air separation method utilizing LNG cold energy |
| CN113587551B (en) * | 2021-07-14 | 2022-11-18 | 四川空分设备(集团)有限责任公司 | Air separation system and method for producing liquid oxygen, liquid nitrogen and liquid argon by using LNG cold energy |
| CN114017992A (en) * | 2021-11-09 | 2022-02-08 | 四川空分设备(集团)有限责任公司 | Air separation system suitable for LNG cold energy load changes |
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