CN100357685C - Method and device for separating air - Google Patents

Method and device for separating air Download PDF

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Publication number
CN100357685C
CN100357685C CNB2004100651899A CN200410065189A CN100357685C CN 100357685 C CN100357685 C CN 100357685C CN B2004100651899 A CNB2004100651899 A CN B2004100651899A CN 200410065189 A CN200410065189 A CN 200410065189A CN 100357685 C CN100357685 C CN 100357685C
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nitrogen
air
tower
decompressor
liquid
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CN1616909A (en
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江楚标
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SUZHOU XINGLU AIR SEPARATION PLANT SCIENCE AND TECHNOLOGY DEVELOPMENT Co Ltd
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SUZHOU XINGLU AIR SEPARATION PLANT SCIENCE AND TECHNOLOGY DEVELOPMENT Co Ltd
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25JLIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02Processes 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
    • F25J3/04Processes 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
    • F25J3/04151Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
    • F25J3/04187Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
    • F25J3/04218Parallel arrangement of the main heat exchange line in cores having different functions, e.g. in low pressure and high pressure cores
    • F25J3/04224Cores associated with a liquefaction or refrigeration cycle
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25JLIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02Processes 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
    • F25J3/04Processes 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
    • F25J3/04248Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04278Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using external refrigeration units, e.g. closed mechanical or regenerative refrigeration units
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25JLIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02Processes 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
    • F25J3/04Processes 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
    • F25J3/04248Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04284Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams
    • F25J3/0429Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams of feed air, e.g. used as waste or product air or expanded into an auxiliary column
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25JLIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02Processes 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
    • F25J3/04Processes 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
    • F25J3/04248Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04284Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams
    • F25J3/04309Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams of nitrogen
    • F25J3/04315Lowest pressure or impure nitrogen, so-called waste nitrogen expansion
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25JLIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02Processes 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
    • F25J3/04Processes 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
    • F25J3/04248Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04375Details relating to the work expansion, e.g. process parameter etc.
    • F25J3/04393Details relating to the work expansion, e.g. process parameter etc. using multiple or multistage gas work expansion
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25JLIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02Processes 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
    • F25J3/04Processes 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
    • F25J3/04406Processes 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
    • F25J3/04412Processes 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
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25JLIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2215/00Processes characterised by the type or other details of the product stream
    • F25J2215/40Air or oxygen enriched air, i.e. generally less than 30mol% of O2
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25JLIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2270/00Refrigeration techniques used
    • F25J2270/90External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration

Abstract

The present invention provides a device and a method for separating air, which relates to a method and a device utilizing rectification to separate air under the low temperature. In the air separation process, the present invention utilizes two expansion machines of different working mediums of raw material air for expanding and refrigerating and back flow waste nitrogen (or back flow nitrogen). The raw material air for expanding and refrigerating and the back flow waste nitrogen (or the back flow nitrogen) are expanded to do work outwards under different pressures and different temperatures, which provides cold quantity for the air separation process. A double rectification tower is adopted in the separation process, and is composed of a lower tower, an upper tower and a condensation evaporator, wherein the condensation evaporator is arranged between the lower tower and the upper tower. The operation pressure of the lower tower is above 0.65Mpa (gauge pressure), and the operating pressure of the upper tower is above 0.08Mpa (gauge pressure). The method and the device are used for separating the air, and the power consumption of unit products can be obviously decreased. The cost performance ratio can be optimized, and the use and the repair are convenient and economic.

Description

A kind of method and apparatus of air separation
Technical field the present invention relates to a kind of method and apparatus of air separation, specially refers to the method and apparatus that utilizes rectifying to come separation of air at low temperatures.
Background technology is before the present invention proposes, and utilizing rectifying to come separation of air at low temperatures is a kind of known industrial production technology.Usual way is: the air of process compressor compresses cools off in chilldown system and remove water vapour in cleaning system, is divided into two strands of air-flows behind the objectionable impurities such as carbon dioxide.One air-flow is that swell refrigeration flows with air, and its enters heat exchanger after through the cooling of supercharger supercharging and water cooler, enters decompressor after reducing temperature, and air externally does work, and after the step-down cooling, gets back to the import of compressor or removes water-cooling tower after returning the heat exchanger re-heat again.Another strand air-flow is for separating with air stream, and it cools to Eat and temperature or part with the bottom that enters tower under the rectifying column behind the liquid through heat exchanger.Rectifying column generally by following tower, form by last tower and condenser/evaporator.Air obtains initial gross separation at Xia Tazhong, obtains to contain the more oxygen-enriched liquid air of oxygen in the bottom, and oxygen-enriched liquid air enters Shang Ta through cold excessively and throttling expansion after being drawn down tower, as the phegma of last tower.The top of following tower obtains nitrogen, and few product that partly can be used as is heated the outer confession in back, and condensation becomes liquid nitrogen to all the other nitrogen with the liquid oxygen heat exchange in condenser/evaporator.The part of this liquid nitrogen becomes the phegma of tower down, and another part liquid nitrogen enters Shang Ta through crossing cold major part through throttling expansion after being drawn down tower, and as the phegma of last tower, few part also can be used as product and supplies outward.Bottom at last tower obtains liquid oxygen, a part of liquid oxygen can be used as product and draws, most liquid oxygen is heated as gas oxygen by nitrogen in condenser/evaporator, a part of gas oxygen also can be used as product and is heated the outer confession in back, and most gas oxygen then participates in rectifying as ascending air.The top of last tower can obtain nitrogen and (or) dirty nitrogen.Suitable position at last tower can also extracting go out to contain the higher fraction of argon, can obtain the product argon at argon producing system by rectifying.At this moment following tower can not go out pure liquid nitrogen and go out liquid nitrogen fraction, goes up tower and also only goes out dirty nitrogen.Adopt such method and apparatus to come separation of air to obtain the oxygen of different shape, nitrogen and argon, particularly liquid oxygen, nitrogen product and (or) pressure oxygen, nitrogen product, the power consumption of unit product is office.
Summary of the invention the objective of the invention is to propose the method and apparatus of air separation under a kind of new low temperature, makes the bigger decline of power consumption of unit product.The ratio of performance to price of device is better.Working service is also easier.
The present invention is achieved by the following technical measures.Major technique feature of the present invention is: in the process of air separation, used the decompressor of swell refrigeration with raw air and these two kinds of different working medium of returning polluted nitrogen (or nitrogen reflux).Swell refrigeration expands with under each comfortable different pressure of raw air and returning polluted nitrogen (or nitrogen reflux) and the different temperature, and outwards acting is for air separation process provides cold.Double rectification column is adopted in separation process, and rectifying column is by following tower, and the condenser/evaporator between Shang Ta and two towers is formed.The operating pressure of following tower is that the operating pressure of last tower is more than the 0.08MPa more than the 0.65MPa (gauge pressure, down together).And returning polluted nitrogen (or nitrogen reflux) decompressor is a booster expansion turbine.
The air of process compressor compresses is in cooling in chilldown system and remove water vapour in cleaning system, is divided into two strands of air-flows behind the objectionable impurities such as carbon dioxide.One air-flow is that swell refrigeration flows with air, its goes into main heat exchanger through the cooling of decompressor supercharger supercharging and water cooler is laggard, enters decompressor after reducing temperature, and air externally does work, after the step-down cooling, return again and get back to the import of compressor after main heat exchanger is heated or remove water-cooling tower.Another strand air-flow flows for separating with air, and its cools to saturation temperature through main heat exchanger or partly with behind the following tower bottom that enters rectifying column behind the liquid, becomes the ascending air of tower down, falls the abundant contact of liquid stream in the column plate up and down and carries out the exchange of heat and quality.Bottom at following tower obtains to contain the more oxygen-enriched liquid air of oxygen.After this oxygen-enriched liquid air was drawn down tower, cold excessively by the returning polluted nitrogen (and nitrogen reflux) that is come by last top of tower through liquid air subcooler earlier, entering Shang Ta through throttling expansion again became one of phegma of going up tower.The nitrogen that obtains at the top of following tower, small part can be used as product and are heated the outer confession in back.Be condensed into liquid nitrogen with the liquid oxygen heat exchange in the condenser/evaporator of most of nitrogen between Liang Ta.The part of this liquid nitrogen becomes the phegma of tower down.Cold excessively by the returning polluted nitrogen (and nitrogen reflux) that is come by last top of tower through liquid nitrogen subcooler after remaining liquid nitrogen is drawn from condenser/evaporator, small part supplies outward as product; The top that the throttling expansion of most of process enters tower becomes another phegma of going up tower.Above-mentioned two strands of phegmas become the decline liquid stream of going up tower.Decline liquid stream fully contacts the exchange of carrying out heat and quality with ascending air on column plate.Bottom at last tower obtains liquid oxygen, and small part can be used as the outer confession of product, is heated into gas oxygen by nitrogen in the condenser/evaporator of most of liquid oxygen between Liang Ta, and small part gas oxygen can be used as product and is heated the outer confession in back, and remaining gas oxygen becomes the ascending air of going up tower.The returning polluted nitrogen (or nitrogen reflux) that last top of tower obtains enters returning polluted nitrogen (or nitrogen reflux) decompressor, and gas externally does work, and returns after the step-down cooling and enters the technology precalculated position after main heat exchanger is heated.When the top of last tower obtains a large amount of pure nitrogen gas products when (claiming nitrogen reflux again), the gas that enters returning polluted nitrogen (or nitrogen reflux) decompressor is exactly product nitrogen gas (nitrogen reflux).
In the present invention, the temperature of the returning polluted nitrogen (or nitrogen reflux) that obtains at the top of last tower is lower, can be heated in liquid nitrogen subcooler and liquid air subcooler.Therefore returning polluted nitrogen (or nitrogen reflux) decompressor then can be positioned at before the liquid nitrogen subcooler; Or be positioned in the middle of liquid nitrogen subcooler and the liquid air subcooler; Or be positioned at after the liquid air subcooler.
In the present invention, the gas that enters returning polluted nitrogen (or nitrogen reflux) decompressor also can be taken from the passage of the returning polluted nitrogen (or nitrogen reflux) in the main heat exchanger.
In the present invention, swell refrigeration is to start operation simultaneously with air expander and returning polluted nitrogen (or nitrogen reflux) decompressor.
In the present invention, returning polluted nitrogen (or nitrogen reflux) decompressor is a booster expansion turbine.
In the present invention, following tower does not go out pure liquid nitrogen and when going out liquid nitrogen fraction, last tower also only goes out dirty nitrogen.
In the present invention, containing the higher argon fraction of argon in the extraction of the appropriate location of last tower goes argon producing system to make the argon product.
In the present invention, the low temperature forecooler is set also, by the refrigeration unit in the external world, as freon refrigeration unit, ammonia refrigeration unit etc. provides cold to relevant gas flow.
In the present invention, high pressure heat exchanger and cryogenic pump are set also, outside for liquid product the time, can also be outward for compressed product gas in the part.
After the invention process abovementioned technology, the power consumption of unit product significantly decreases, and initial estimate can reduce by 10%.Can optimize the ratio of performance to price.Use and keep in repair also more convenient and economical.
Appended drawings 1,2 is respectively air separating method and the device schematic diagram of embodiment one, two.Equipment serial number is as follows in interior: 1 is the decompressor supercharger, and 2 is water cooler, and 3 is main heat exchanger, 4 is the swell refrigeration air expander, 5 is rectifying column, and 6 are following tower, and 7 is last tower, 8 is condenser/evaporator, 9 is liquid air subcooler, and 10 is liquid nitrogen subcooler, and 11 is returning polluted nitrogen (or nitrogen reflux) decompressor, 12 is the low temperature forecooler, and 13 is the cryogenic cooling unit.Xiang Guan material flow is also made following numbering in addition: 101 are raw air, and 102 is cooling raw air, and 103 are the separation raw air, 104 is oxygen-enriched liquid air, and 105 is returning polluted nitrogen (or nitrogen reflux), and 106 is the liquid oxygen product, 107 is liquid nitrogen, and 108 is liquid nitrogen product, and 109 is the argon cut.
The invention will be further described below in conjunction with drawings and Examples for the specific embodiment.
Embodiment is once the cooling in chilldown system of overcompression machine compression and remove water vapour in cleaning system, and the raw air 101 behind the objectionable impurities such as carbon dioxide is divided into two strands of air-flows.One air-flow is that swell refrigeration flows 102 with raw air, its goes into main heat exchanger 3 through 2 coolings of decompressor supercharger 1 supercharging and water cooler are laggard, enter swell refrigeration air expander 4 after reducing temperature, air externally does work, after the step-down cooling, get back to the import of compressor or remove water-cooling tower after returning main heat exchanger 3 re-heats again.Another strand air-flow is to separate with raw air stream 103, after its cools to saturation temperature or partly be with liquid through main heat exchanger 3, enters the following tower 6 of rectifying column 5, and rectifying column 5 is by following tower 6, and the condenser/evaporator 8 between last tower 7 and two towers is formed.The operating pressure of following tower 6 is 0.65MPa, and the operating pressure of last tower 7 is 0.08MPa.Separation enters down the bottom of tower 6 with raw air stream 103, becomes the ascending air of tower 6 down, falls liquid stream in the column plate up and down and fully contacts and carry out the exchange of heat and quality.Bottom at following tower 6 obtains to contain the more oxygen-enriched liquid air of oxygen 104.After this oxygen-enriched liquid air 104 was drawn down tower 6, cold excessively by the returning polluted nitrogen 105 that is come by last tower 7 tops through liquid air subcooler 9 earlier, entering tower 7 through throttling expansion again became one of phegma of going up tower 7.At the nitrogen that the top of following tower 6 obtains, small part can be used as product and is heated the outer confession in back, is condensed into liquid nitrogen with the liquid oxygen heat exchange in the condenser/evaporator 8 of most of nitrogen between Liang Ta.The part of this liquid nitrogen becomes the phegma of tower 6 down.Remaining liquid nitrogen 107 is cold excessively by the returning polluted nitrogen 105 that is come by last tower 7 tops through liquid nitrogen subcooler 10, and small part is as product 108 outer confessions; The top that the throttling expansion of most of process enters tower 7 becomes another phegma of going up tower 7.Above-mentioned two strands of phegmas become the decline liquid stream of going up tower 7.Decline liquid stream fully contacts the exchange of carrying out heat and quality with ascending air on column plate.Bottom at last tower 7 obtains liquid oxygen, the small part liquid oxygen can be used as product 106 outer confessions, be heated into gas oxygen by nitrogen in the condenser/evaporator 8 of all the other liquid oxygen between Liang Ta, small part gas oxygen can be used as product and is heated the outer confession in back, and its residual air oxygen becomes the ascending air of going up tower 7.After being heated, the returning polluted nitrogen 105 that obtains at the top of last tower 7 enters returning polluted nitrogen decompressor 11 in liquid nitrogen subcooler 9 and liquid air subcooler 10, gas externally does work, enter main heat exchanger 3 and raw air heat exchange again after the step-down cooling, go to the technology precalculated position afterwards.Swell refrigeration is to start operation simultaneously with air expander 4 and returning polluted nitrogen decompressor 11.
Containing the higher argon fraction 109 of argon in the extraction of the appropriate location of last tower goes argon producing system to make the argon product.
Embodiment two in order to reduce the energy consumption of product, is provided with low temperature forecooler 12 at the suitable position of main heat exchanger 3 in the situation of air separating method identical with embodiment one and device.And adopt cryogenic cooling unit 13 to provide cold to air.
The present invention is not limited to above-mentioned embodiment; no matter on its method or device, do any variation; all decompressors with these two kinds of different working medium of air and returning polluted nitrogen; and the operating pressure of following tower is more than the 0.65MPa (gauge pressure), and the operating pressure of last tower is that above twin-stage rectifying air separating method of 0.08MPa (gauge pressure) and device all drop within protection scope of the present invention.

Claims (9)

1. the method for an air separation comprises:
(1) through compressor compresses, the chilldown system cooling and in cleaning system, remove objectionable impurities after air (101) be divided into swell refrigeration with raw air stream (102) with separate with raw air and flow (103),
(2) swell refrigeration is gone into main heat exchanger (3) with raw air stream (102) through decompressor supercharger (1) supercharging and water cooler (2) cooling are laggard, enter swell refrigeration raw air decompressor (4) after reducing temperature, at swell refrigeration step-down cooling back return main heat exchanger (3) in the raw air decompressor (4), go out the water-cooling tower of getting back to compressor inlet or denitrification water system behind the main heat exchanger (3)
(3) separate with entering rectifying column (5) behind raw air stream (103) the process main heat exchanger (3), in rectifying column (5), be separated into the oxygen of various forms, nitrogen product and argon cut,
It is characterized in that:
(1) returning polluted nitrogen (105) or the nitrogen reflux that obtains from the last tower (7) of rectifying column (5) enters returning polluted nitrogen or nitrogen reflux decompressor (11), and enter after step-down is lowered the temperature in this decompressor (11) and go to the technology precalculated position after heat exchanger (3) is heated,
(2) swell refrigeration is to start operation simultaneously with raw air decompressor (4) and returning polluted nitrogen or nitrogen reflux decompressor (11),
(3) operating pressure of the following tower (6) of rectifying column (5) is more than the 0.65MPa (gauge pressure), and upward the operating pressure of tower (7) is more than the 0.08MPa (gauge pressure).
2. the method for the described a kind of air separation of claim 1 is characterized in that: returning polluted nitrogen (105) that obtains from the last tower (7) of rectifying column (5) or nitrogen reflux enter returning polluted nitrogen or nitrogen reflux decompressor (11) before entering liquid nitrogen subcooler (10).
3. the method for the described a kind of air separation of claim 1 is characterized in that: the returning polluted nitrogen (105) or the nitrogen reflux that obtain from the last tower (7) of rectifying column (5) enter returning polluted nitrogen or nitrogen reflux decompressor (11) afterwards through liquid nitrogen subcooler (10).
4. the method for the described a kind of air separation of claim 1 is characterized in that: the returning polluted nitrogen (105) or the nitrogen reflux that obtain from the last tower (7) of rectifying column (5) enter returning polluted nitrogen or nitrogen reflux decompressor (11) afterwards through liquid nitrogen subcooler (10) and liquid air subcooler (9).
The method of the described a kind of air separation of 5 claims 1, it is characterized in that: returning polluted nitrogen (105) that obtains from the last tower (7) of rectifying column (5) or nitrogen reflux go into to enter after main heat exchanger (3) tentatively is heated after returning polluted nitrogen or nitrogen reflux decompressor (11) step-down lower the temperature through liquid nitrogen subcooler (10) and liquid air subcooler (9) are laggard, enter and go to the technology precalculated position after main heat exchanger (3) is heated.
6. the device of an air separation, successively by
(1) air is pressurizeed and remove the compressor that objectionable impurities makes it to become raw air, chilldown system, and cleaning system,
(2) the decompressor supercharger (1) that swell refrigeration is carried out supercharging and cooling with air, water cooler (2), and the swell refrigeration that swell refrigeration is carried out step-down cooling with air is with raw air decompressor (4),
(3) various fluid is carried out the main heat exchanger (3) of cold and hot exchange, liquid air subcooler (9) and liquid nitrogen subcooler (10),
(4) will separate rectifying column (5) composition that carries out separating obtained product with raw air,
Utilize pipeline successively with compressor, chilldown system, cleaning system, decompressor supercharger (1), water cooler (2), main heat exchanger (3) interconnects with rectifying column (5); Behind rectifying column (5), still utilize pipeline successively with liquid nitrogen subcooler (10), liquid air subcooler (9), main heat exchanger (3) interconnects,
It is characterized in that:
(1) before, or between liquid nitrogen subcooler (10) and the liquid air subcooler (9), or returning polluted nitrogen or the nitrogen reflux decompressor (11) that returning polluted nitrogen or nitrogen reflux are carried out the step-down cooling arranged between liquid air subcooler (9) and the main heat exchanger (3) at liquid nitrogen subcooler (10),
(2) rectifying column (5) is a double rectification column, is the above following tower (6) of 0.65MPa (gauge pressure) by operating pressure, and operating pressure is that above last tower (7) of 0.08MPa (gauge pressure) and the condenser/evaporator (8) between two towers are formed.
7. a kind of air-separating plant according to claim 6 is characterized in that: returning polluted nitrogen or nitrogen reflux decompressor (11) are booster expansion turbines.
8. the device of a kind of air separation according to claim 6 is characterized in that: be provided with low temperature forecooler (12).
9. the device of a kind of air separation according to claim 6, it is characterized in that: providing the refrigeration unit of cold by the external world is cryogenic cooling unit (13).
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CN102052821A (en) * 2011-01-07 2011-05-11 苏州市兴鲁空分设备科技发展有限公司 Air separation method
CN102032756A (en) * 2011-01-07 2011-04-27 苏州市兴鲁空分设备科技发展有限公司 Air separation method
CN102829605A (en) * 2012-09-08 2012-12-19 浙江海天气体有限公司 Air separation device for supplying cold energy for preparing liquid oxygen by utilizing liquid nitrogen backward filling

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EP0959314A2 (en) * 1998-05-22 1999-11-24 Air Products And Chemicals, Inc. Indirect fired gas turbine integrated with an air separation unit
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EP0881444A2 (en) * 1997-05-28 1998-12-02 Praxair Technology, Inc. Method and apparatus for control of an integrated cryogenic air separation unit/gas turbine system
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