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
  • F25J3/04151—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
  • F25J3/042—Division of the main heat exchange line in consecutive sections having different functions having an intermediate feed connection
• • 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
  • F25J3/04084—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 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
  • F25J3/04006—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
  • F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product 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
  • F25J3/04284—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
  • F25J3/04375—Details relating to the work expansion, e.g. process parameter etc.
  • F25J3/04387—Details relating to the work expansion, e.g. process parameter etc. using liquid or hydraulic turbine expansion
• • 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
  • 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
  • F25J3/04763—Start-up or control of the process; Details of the apparatus used
  • F25J3/04866—Construction and layout of air fractionation equipments, e.g. valves, machines
  • F25J3/04872—Vertical layout of cold equipments within in the cold box, e.g. columns, heat exchangers etc.
  • F25J3/04878—Side by side arrangement of multiple vessels in a main column system, wherein the vessels are normally mounted one upon the other or forming different sections of the same 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
  • F25J2200/00—Processes or apparatus using separation by rectification
  • F25J2200/20—Processes or apparatus using separation by rectification in an elevated pressure multiple column system wherein the lowest pressure column is at a pressure well above the minimum pressure needed to overcome pressure drop to reject the products to atmosphere
• • 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
  • F25J2200/00—Processes or apparatus using separation by rectification
  • F25J2200/90—Details relating to column internals, e.g. structured packing, gas or liquid distribution
• • 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
  • F25J2240/00—Processes or apparatus involving steps for expanding of process streams
  • F25J2240/02—Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream
  • F25J2240/10—Expansion of a process fluid in a work-extracting turbine (i.e. isentropic expansion), e.g. of the feed stream the 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
  • F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
  • F25J2290/10—Mathematical formulae, modeling, plot or curves; Design methods
• • 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
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S62/00—Refrigeration
  • Y10S62/902—Apparatus
  • Y10S62/903—Heat exchange structure

Definitions

• the present invention relates to an air separation process by cryogenic distillation and an installation for the implementation of this process.
• the goal of an engineer who creates an air separation process is to minimize energy costs. It is well known to use a double air separation column to produce oxygen at low energy, in particular on the one hand to minimize the discharge pressure of the air compressor by reducing the pressure drops in the exchange line, by reducing the temperature difference in the main vaporizer, and on the other hand to maximize the oxygen extraction efficiency by reducing the temperature difference in the exchange line, by choosing a large number of theoretical distillation trays and installing a sufficient number of sections of structured packing or trays.
• low pressure columns have four sections of structured packing or trays, including two sections between the bottom of the low pressure column and a rich liquid inlet, which is an oxygen-enriched liquid taken from the bottom of the column. medium pressure. These two sections are necessary to ensure very efficient distillation in the bottom of the low pressure column.
• medium pressure columns have four sections of structured packing or trays, including two sections between the supply of liquid air and the withdrawal of lean liquid.
• the purified and compressed air sent to the columns cools in an exchange line comprising which would normally have a volume of more than 200m 3 , therefore with a ratio between the total air flow sent to the exchange line and the volume of the exchange line which would be around 2000 Nm 3 / h / m 3 in the case of the example described below.
• the frigories required for distillation are frequently supplied by an air flow sent to an insufflation turbine feeding the low column near- sion and / or an air flow sent to a Claude turbine.
• the ratio between the quantity of air sent to the exchange line and the flow rate sent to the insufflation turbine would normally be between 5: 1 and 15: 1 in the case of the example described below. In some cases when energy is inexpensive or even free, it pays to reduce equipment costs while increasing energy requirements.
• An object of the present invention is to reduce the investment cost of the air separation installation and to increase its energy by reducing the size of the exchangers (therefore by increasing the pressure losses and the temperature differences in the exchange line and increasing the temperature difference at the main vaporizer), reducing the size of the distillation columns (minimizing the number of theoretical plates and the number of sections of packing or plates) and reducing the size of the refrigeration turbine (by increasing its intake temperature to decrease its flow).
• the quantity of air V sent to the exchange line includes all the air sent for distillation, as well as any air flows which are expanded and then sent to the atmosphere.
• a structured packing section is a section of structured packing between a fluid inlet or outlet.
• Structured packings are typically of the corrugated-cross type but may have other geometries.
• a method of air separation by cryogenic distillation using an apparatus comprising a medium pressure column and a low pressure column thermally connected together in which an amount of compressed and purified air V is cooled in an exchange line to a cryogenic temperature and is sent at least in part to the medium pressure column, flows enriched in oxygen and nitrogen are sent from the medium pressure column to the low pressure column and enriched flows nitrogen and oxygen are withdrawn from the low pressure column, characterized in that the medium pressure column operates between 6 and 9 bar abs and the ratio between the quantity of total air V entering the exchange line and the total volume of the exchange line is between 3000 and 6000 Nm 3 / h / m 3 .
• the maximum temperature difference at the cold end of the exchange line is 10 ° C;
• a liquid enriched in oxygen is sent from the low pressure column to a tank reboiler where it is partially vaporized by heat exchange with a gas enriched in nitrogen coming from the medium pressure column, the reboiler having a ⁇ T d '' at least 2.5K;
• the ratio between the quantity of air V and the air flow rate sent to the insufflation turbine is between 20 and 40;
• the medium pressure column contains two or three sections of structured packing and / or the low pressure column contains three sections of structured packing;
• At least one liquid flow is withdrawn from a column, possibly pressurized, and vaporized in the exchange line; - the medium pressure column operates at between 6.5 and 8.5 bar abs.
• the pressure losses in the exchange line are greater than 200 mbar for a residual nitrogen flow coming from the low pressure column.
• a liquid air expansion turbine is supplied by all or part of a liquid air flow leaving the exchange line and / or ii) a refrigeration unit or chilled water produced by a refrigeration unit (which can be the same water circuit as that used to cool the air at the inlet of the treatment) cools the air at the outlet of an air suppressor and / or l at the lowest pressure and / or iii) an increased ratio of air is sent to the blowing turbine so that the ratio between the quantity of air V sent to the exchange line and the flow rate of air D sent to the insufflation turbine is less than 20: 1.
• the purity of the oxygen is between 85 and 100%, preferably between 95 and 100%.
• an air separation installation for producing gases from the air according to a process described above comprising the medium pressure column containing two or three sections of structured packings and / or the low pressure column containing three sections of structured packing.
• the installation may include an argon column supplied from the low pressure column.
• An insufflation turbine expands air and sends at least part of it to the low pressure column of a double column.
• An air flow 1 of 475,000 Nm 3 / h at 7 bar abs. from a purification unit (not glossy) is divided into three.
• a first flow 3 is boosted in the booster 5 to the pressure required to vaporize the liquid oxygen, for example.
• the high pressure air AIR HP 7 is sent to the exchange line 10 but does not reach the cold end, being cooled to -160 ° C, expanded, liquefied and sent to the two columns 9 and 11, respectively medium pressure and low pressure of a double air separation column.
• a second non-overpressed AIR MP 13 flow is also sent to the exchange line 10 which it partially crosses up to -140 ° C. before being sent to the tank of the medium pressure column 9.
• a third flow 15 of 20,000 Nm 3 / h is sent to a booster 17, cooled in the exchange line partially is expanded in an insufflation turbine 19, with an inlet temperature of -80 ° C, before to be sent to the low pressure column 11.
• the ratio between the air flow rate sent to the insufflation turbine 19 and the quantity of air sent to the exchange line is 24: 1.
• the pressure drops in the exchange line 10 are around 300 mbar for the air flow 13 at the lowest pressure and around 250 mbar for the residual nitrogen 35.
• the double column is a conventional device except with regard to its dimensions and the number of theoretical plates of the columns because the medium pressure column contains 40 and the low pressure column 45 and as regards the temperature difference for the reboiler 21 which is higher than 2.5 ° C.
• liquids enriched with oxygen (rich liquid LR) and nitrogen (lean liquid LP) are sent from the medium pressure column to the low pressure column after under cooling in the exchanger SR and expansion in a valve.
• the low pressure column 11 contains three sections of structured packings, including a section I in a tank between the bottom of the column and the arrival of rich liquid (which is combined with the arrival of blown air), a section II between 'arrival of rich liquid and the arrival of liquid air and a section III between the arrival of liquid air and the arrival of lean liquid.
• the medium pressure column 9 contains three sections of structured packings, including a section I in a tank between the bottom of the column and the liquid air inlet, a section ⁇ between the liquid air inlet and the lean liquid outlet LP and a section III between the lean liquid outlet LP and the medium pressure nitrogen outlet 31. Obviously if there is no withdrawal of liquid nitrogen or nitrogen gas, the medium pressure column contains only two sections, section III being deleted.
• the tank reboiler 21 of the low pressure column 11 is in fact integrated with the medium pressure column 9 and is heated by a flow of medium pressure nitrogen from this column 9.
• a flow of liquid oxygen 23 coming from the tank of the low pressure column 11 is pumped to overcome the hydrostatic height and arrives at the reboiler 21 where it partially vaporizes, a gas flow 25 being returned to the low pressure column below the exchange means I and a liquid flow 27 being sent to the pump 29 where it is pressurized to its operating pressure.
• the pumped flow 27 is vaporized in the exchange line 10.
• a liquid nitrogen flow 31 is drawn off at the head of the medium pressure column 9 above the section III, pumped and also vaporizes in the exchange line 10 .
• the values of the pressures of liquid nitrogen and liquid oxygen can have any value, as long as the exchange line 10 is designed as a function of the maximum air pressure required for vaporization. It will be understood that the invention also applies to the case in which a single flow of liquid vaporizes in the exchange line 10, or no liquid withdrawn from a column vaporizes in the installation.
• the liquid flow (s) can vaporize against a cycle nitrogen flow.
• the liquid flow rate (s) can alternatively vaporize in a dedicated exchanger used only to vaporize the liquid flow rate (s) against an air flow or a cycle nitrogen flow.
• the process can also produce liquid oxygen and / or liquid nitrogen and / or liquid argon as the final (final) product (s).
• Nitrogen gas 33, 35 can be withdrawn from the medium pressure column
• the nitrogen gas 35 heats up in the sub-cooler SR.
• a flow of gaseous oxygen can be drawn off as the final product of the low pressure column 11 (not shown). This flow can possibly be pressurized in a compressor.
• a medium pressure nitrogen gas flow NG MP 33 and a low pressure residual nitrogen flow 35 heat up in the exchange line 10.
• the flow NR 35 can be used to regenerate the air cleaning system so known and / or can be sent to a gas turbine.
• a process as described makes it possible to produce oxygen OG HP at 99.5% with a yield of more than 97%.
• This oxygen is typically used in a gasifier powered by a fuel, such as natural gas.
• the low pressure column 11 may be next to the medium pressure column 9, as in the example or else above it.
• the required frlgories can be supplied in using i) a liquid air expansion turbine supplied with all or part of the HP 7 liquid air flow at the outlet of the exchanger 10 and / or ii) a refrigeration unit or chilled water produced by a refrigeration unit (which can be the same water circuit as that used to cool the air at the inlet of the treatment) to cool the air at the outlet of the air blower 5 and / or the air at the outlet of the booster 17 and / or the air MP 13 and / or iii) by sending an increased ratio of air to the blowing turbine 19 so that the ratio between the quantity of air V sent to the line exchange and the air flow D sent to the insufflation turbine is less than 20: 1.
• the boosters 5,17 and / or the main compressor can (can) be driven by electricity, by steam turbine and / or by gas turbine.
• the turbine 19 can have a dedicated booster or a generator.
• the installation can also include conventional elements, such as a Claude turbine, a hydraulic turbine, a medium or low pressure nitrogen turbine, one or more columns for producing argon, a column for mixing supplied by air. and the oxygen of the low pressure column, a column operating at intermediate pressure, for example supplied by the rich liquid and / or air, a low pressure column with double or triple reboiler etc.

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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)

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• 2001
  • 2001-10-17 FR FR0113362A patent/FR2830928B1/fr not_active Expired - Fee Related
• 2002
  • 2002-10-08 JP JP2003536669A patent/JP2005505740A/ja not_active Withdrawn
  • 2002-10-08 US US10/492,758 patent/US7219514B2/en not_active Expired - Lifetime
  • 2002-10-08 EP EP02793161A patent/EP1446621A2/fr not_active Withdrawn
  • 2002-10-08 WO PCT/FR2002/003420 patent/WO2003033978A2/fr not_active Ceased

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