Classifications

• • 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
  • F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
  • F25J3/04078—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression
  • F25J3/0409—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression of oxygen
• • 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
  • F25J3/04163—Hot end purification of the feed air
  • F25J3/04169—Hot end purification of the feed air by adsorption of the impurities
• • 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
  • F25J3/04193—Division of the main heat exchange line in consecutive sections having different functions
  • F25J3/04206—Division of the main heat exchange line in consecutive sections having different functions including a so-called "auxiliary vaporiser" for vaporising and producing a gaseous product
• • 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
  • F25J3/0423—Subcooling of liquid process streams
• • 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
• • 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
  • F25J3/04284—Generation 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
  • F25J3/0429—Generation 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
  • F25J3/04303—Lachmann expansion, i.e. expanded into oxygen producing or low pressure column
• • 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
  • F25J3/04284—Generation 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
  • F25J3/04309—Generation 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
• • 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
• • 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
  • F25J2210/00—Processes characterised by the type or other details of the feed stream
  • F25J2210/42—Nitrogen
• • 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
  • F25J2210/00—Processes characterised by the type or other details of the feed stream
  • F25J2210/50—Oxygen
• • 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
  • F25J2215/50—Oxygen or special cases, e.g. isotope-mixtures or low purity O2
• • 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
  • F25J2245/00—Processes or apparatus involving steps for recycling of process streams
  • F25J2245/40—Processes or apparatus involving steps for recycling of process streams the recycled stream being air
• • 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
  • F25J2250/30—External or auxiliary boiler-condenser in general, e.g. without a specified fluid or one fluid is not a primary air component or an intermediate fluid
  • F25J2250/40—One fluid being air
• • 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
  • F25J2250/30—External or auxiliary boiler-condenser in general, e.g. without a specified fluid or one fluid is not a primary air component or an intermediate fluid
  • F25J2250/50—One fluid being oxygen
• • 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
  • F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
  • F25J2290/12—Particular process parameters like pressure, temperature, ratios

Definitions

• the present invention relates to an apparatus and a method for separating air by cryogenic distillation.
• an air separation device comprising a double column with a first column operating at a first pressure and a second column operating at a second pressure, lower than the first pressure.
• the head of the first column produces a gas which condenses in a reboiler of the second column.
• Air cleaning is generally carried out at a pressure equal to or greater than that of the first pressure. This makes it possible to reduce the volume of the purification unit.
• JPH1 1063810 and EP1050730 are similar to US5934105.
• the air flow going to the first column is approximately 66% of the total purified flow, for example to produce 96% oxygen. This means that 34% of the air flow must be passed at a relatively low pressure in the turbine. According to the present invention, between 6 and 8% of the air is expanded in an air turbine, therefore the turbine according to the prior art is at least 4 to 5 times larger due to the volume flow.
• the invention provides a process which consumes 1% less energy (2% less if we consider a turbine efficiency reduced by 5% pt) compared to the prior art (for example, according to EP1050730); according to the method of EP1050730, the purification is carried out at a pressure between the first and the second pressure.
• the expansion rate of the EP1050730 process is low, between 1: 2: 1 and 3.8: 1, preferably between 1: 4: 1 and 2.5: 1, while conventional cryogenic turbines are within a range of relaxation ratio between 4: 1 and 10: 1.
• the invention uses an expansion rate which remains at the lower limit of this range, thus avoiding having a substantially degraded turbine efficiency.
• the inlet pressure of the purification unit is typically 2.5 bara (instead of approximately 1.3 bara according to the invention).
• This process uses a first compressor with several, typically two, stages with cooling between two stages.
• the compressor which compresses all the air has a single stage, therefore no cooling between two stages.
• US5666824 describes a method according to the preamble of claim 1 but in which the first flow is at least partially condensed in an intermediate condenser of the second column. If a gas is formed, it is itself condensed in another intermediate condenser of the second column and the liquid thus formed is sent to the head of the second column. Thus the first flow is not sent directly to the distillation.
• WO2013 / 014252 describes in FIG. 6 a process in which a first part of the air is cooled to its dew point in a heat exchanger where an expanded air flow in a turbine is also cooled to its dew point. This is impossible since the residual nitrogen which cools the air flows has already been heated in a sub-cooler. In this case, the nitrogen is too hot to cool the air flows to their dew point and the air flows will be cooled at most to a temperature around 10 ° C above the dew point.
• an air separation device comprising a double column with a first column operating at a first pressure and a second column operating at a second pressure, lower than the first pressure, the second column having a tank reboiler, means for sending a nitrogen-enriched gas from the head of the first column to the tank reboiler and means for sending at least part of the condensed nitrogen enriched gas from the tank reboiler to the head of the first column, a heat exchanger, a purification unit, means for sending air to the purification unit at a third pressure higher than atmospheric pressure by at most 1 bar, a pipe for sending a first flow of purified air in the purification unit at the heat exchanger at a fourth pressure greater than the second pressure by at most 1 bar, a line for introducing the first flow of cooled purified air into the heat exchanger heat in the second column to separate therefrom, a booster, a pipe for sending a second flow of purified air in the purification unit to the booster, a
• the means for producing frigories include at least one expansion turbine for part of the second flow and / or one expansion turbine for a gas rich in nitrogen coming from the first column and / or means for sending a cryogenic liquid from a source external to the double column.
• the means for sending air to the purification unit at the third pressure do not include any compression means apart from a single-stage compressor.
• the device does not include any means of compressing the first flow.
• a first flow of purified air is sent into the purification unit to a heat exchanger at a fourth pressure greater than the second pressure by at most 1 bar, iv) the first flow of cooled purified air is sent into the heat exchanger to the second column, without having relaxed it,
• a second purified air flow is boosted at a fifth pressure between the first pressure and 1 bar above the first pressure, at least part of the second flow is sent at the fifth pressure to the heat exchanger and at least part of the second flow is sent to the first column in gaseous form,
• an oxygen-enriched gas or a nitrogen-enriched gas is drawn off from the double column and it is heated in the heat exchanger to form a product of the process characterized in that the first air flow is sent directly to the second column to separate there without having been condensed in a condenser.
• the part of the air expanded in the turbine represents between 6 and 15% vol, preferably between 6 and 8% of the purified air.
• the oxygen-enriched gas contains at least 80 mol% oxygen.
• the oxygen-enriched gas contains at least 90 mol% of oxygen.
• the oxygen-enriched gas contains less than 98% mol of oxygen.
• the first flow represents between 20 and 30% vol of the purified air flow.
• the second flow represents between 70 and 80% vol of the purified air flow.
• a gas enriched in oxygen and / or a gas enriched in nitrogen is withdrawn from the double column and it (s) is heated in the heat exchanger to form a product of the process by introducing it or introducing them at the cold end of the heat exchanger.
• the oxygen-enriched liquid is pressurized before vaporizing it either in a dedicated vaporizer or in the heat exchanger.
• the oxygen-enriched liquid is vaporized by heat exchange with part of the second flow or with a third flow of pressurized air at a pressure greater than the fifth pressure.
• FIG. 1 represents a method of air separation by cryogenic distillation according to the invention.
• An air separation apparatus by cryogenic distillation comprises a double column with a first column K3 operating at a first pressure and a second column K4 operating at a second pressure, lower than the first pressure, the second column having a tank reboiler M.
• the second column K4 does not contain an intermediate condenser.
• the first pressure is 4.5 bara and the second pressure is 1.13 bara.
• a gas enriched in nitrogen is sent from the head of the first column to the tank reboiler M and at least part of the gas enriched in condensed nitrogen from the tank reboiler is sent to the head of the first column.
• Air at atmospheric pressure is filtered in a filter A, compressed by a blower B having a single stage at a pressure at most 1 bar, preferably at most 0.5 bar, above atmospheric pressure, cooled by a cooling means C and purified with water and carbon dioxide in a single purification unit D in which the air 4 returns to a third pressure higher than atmospheric pressure by at most 1 bar, preferably of at most 0.5 bar.
• the purification unit includes two adsorbent beds used alternately to purify the air, one bed purifying the air while the other is regenerated.
• Air 8 is neither compressed nor expanded and is at a pressure which differs from the second pressure by a pressure equal to the pressure losses in the pipes and the heat exchanger G.
• the first flow 8 represents between 20 and 30% vol of the flow 4 and the second flow 6 represents between 70 and 80% vol of the flow 4.
• the air 8 is sent directly from the purification unit to the second column K2 to be separated there, returning to the column in entirely gaseous form.
• the air 8 cools in the heat exchanger G to a temperature at least 5 ° C above its dew point.
• the flow 6 is boosted in a booster E, cooled in a cooler F and sent to the heat exchanger G.
• the booster E boosts the air 6 to a fifth pressure between the first pressure and 1 bar above the first press.
• the air 6 is divided into two parts 30, 32 at an intermediate level of the exchanger.
• the air 30 leaves the exchanger at an intermediate temperature thereof, for example -125 ° C, is expanded in a turbine 28 until the second pressure and returns in gaseous form, mixed with the flow 8, to be separated in the second column K4.
• the flow 30 can represent between 6 and 15% vol, preferably between 6 and 8% of the air 4.
• the air 32 cools down to the cold end of the exchanger G and is sent to the tank of the first column K3 in essentially gaseous form in order to be separated there.
• the air 8 cools in the heat exchanger G to a temperature at least 5 ° C above its dew point.
• a liquid flow enriched with oxygen 34 is withdrawn from the tank of the first column and sent to a level of the second column which is above the air inlet.
• the air can enter the second column at the same level as that of the arrival of the liquid 34.
• the expanded liquid 34 can be separated in a phase separator: the liquid from the phase separator is sent to column K4 and the vapor phase can be mixed with the air inlet 8.30 in column K4.
• a flow of liquid nitrogen 35 is withdrawn from the head of the first column and sent to the head of the second column.
• Nitrogen gas 36 is drawn off at the head of the second column K4 and is heated in the sub-cooler S and then in the exchanger G. Part 14 of this gas is used to regenerate the purification unit D.
• Gaseous oxygen 29 is withdrawn from the tank of the second column K4.
• the flow 29 preferably contains at least 80 mol% oxygen, or even at least 90 mol% oxygen, but preferably less than 98 mol% oxygen.
• the process produces no liquid flow as the final product.
• the process produces no liquid flow to vaporize to form a final gaseous product, possibly under pressure. It is however possible to produce a small amount of final gaseous product in this way, which can optionally be mixed with the main gaseous product.
• the air 8 and / or the air 30 may be sub-cooled is in the sub-cooler S and then be introduced into the second column K4. Otherwise, the mixture of flows 8 and 30 can be sub-cooled in the sub-cooler S and then be introduced into the second column K4.
• the flow 29 is a flow of gaseous oxygen which heats up in the heat exchanger G from the cold end of the exchanger G.
• the flow 29 can be a flow of rich liquid in pressurized oxygen at a pressure above that of the second column K4.
• the liquid 29 is vaporized either in a dedicated vaporizer (not shown) or in the heat exchanger G.
• the liquid 29 can be vaporized by heat exchange with all the air 32 to partially condense the air 32 which will then be sent to the tank of the first column K3. Otherwise the liquid 29 can be vaporized by heat exchange with part of the air 32 to completely condense this part of the air 32.
• the condensed air will then be sent to the first column tank K3 or to an intermediate point of the first and / or second column.
• part of the purified air can be boosted in a booster at a pressure higher than that of the first column K3 to vaporize the liquid 29.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Thermal Sciences (AREA)
• General Engineering & Computer Science (AREA)
• Health & Medical Sciences (AREA)
• Emergency Medicine (AREA)
• Separation By Low-Temperature Treatments (AREA)
• Oxygen, Ozone, And Oxides In General (AREA)

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• 2018
  • 2018-12-21 FR FR1873736A patent/FR3090831B1/fr active Active
• 2019
  • 2019-12-05 EP EP19868211.4A patent/EP3899389A1/fr active Pending
  • 2019-12-05 CA CA3122855A patent/CA3122855A1/en active Pending
  • 2019-12-05 JP JP2021535172A patent/JP7451532B2/ja active Active
  • 2019-12-05 BR BR112021011589-7A patent/BR112021011589A2/pt unknown
  • 2019-12-05 US US17/416,782 patent/US20220074656A1/en active Pending
  • 2019-12-05 AU AU2019408677A patent/AU2019408677A1/en active Pending
  • 2019-12-05 CN CN201980084384.0A patent/CN113242952B/zh active Active
  • 2019-12-05 WO PCT/FR2019/052934 patent/WO2020128205A1/fr unknown

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