EP1338856A2 - Procédé et installation pour la séparation d'air par distillation cryogénique - Google Patents

Procédé et installation pour la séparation d'air par distillation cryogénique Download PDF

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Publication number
EP1338856A2
EP1338856A2 EP03075304A EP03075304A EP1338856A2 EP 1338856 A2 EP1338856 A2 EP 1338856A2 EP 03075304 A EP03075304 A EP 03075304A EP 03075304 A EP03075304 A EP 03075304A EP 1338856 A2 EP1338856 A2 EP 1338856A2
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Prior art keywords
pressure column
low pressure
stream
air
nitrogen
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German (de)
English (en)
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EP1338856A3 (fr
Inventor
Alain Briglia
Michael Turney
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Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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Air Liquide SA
LAir Liquide SA a Directoire et Conseil de Surveillance pour lEtude et lExploitation des Procedes Georges Claude
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Publication of EP1338856A2 publication Critical patent/EP1338856A2/fr
Publication of EP1338856A3 publication Critical patent/EP1338856A3/fr
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
    • F25J3/04284—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
    • F25J3/04006—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
    • F25J3/04175—Hot end purification of the feed air by adsorption of the impurities at a pressure of substantially more than the highest 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
    • F25J3/04151—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
    • F25J3/04284—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
    • F25J3/04296—Claude expansion, i.e. expanded into the main or 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
    • F25J3/04406—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
    • F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
    • F25J3/04793—Rectification, e.g. columns; Reboiler-condenser
    • 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
    • F25J2235/00—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams
    • F25J2235/06—Lifting of liquids by gas lift, e.g. "Mammutpumpe"
    • 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
    • F25J2245/02—Recycle of a stream in general, e.g. a by-pass stream
    • 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
    • F25J2245/42—Processes or apparatus involving steps for recycling of process streams the recycled stream being 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
    • F25J2290/00—Other details not covered by groups F25J2200/00 - F25J2280/00
    • F25J2290/12—Particular process parameters like pressure, temperature, ratios

Definitions

  • This invention relates to a process and apparatus for the separation of air by cryogenic distillation.
  • the process may be used to produce gaseous oxygen, nitrogen, and/or argon.
  • the first category is known as the classical gas cycle, which utilizes a compressor to pressurize the product gaseous oxygen.
  • the second category is known as the pumping cycle, which utilizes a cryogenic pump to pressurize liquid oxygen, which is then vaporized to produce pressurized product gaseous oxygen.
  • pumping cycle plants There are two main types of pumping cycle plants; the classical pumping cycle and the "offset knee" cycle.
  • Figure 1 describes a typical classical gas cycle plant as taught in the prior art.
  • All the feed air 1 is compressed in a compressor (not shown).
  • the compressed feed air 3 is first purified. This step is not indicated in Figure 1, but typically consists of a series of steps which include cooling, adsorption and filtration.
  • the air is then divided into two parts 3, part 3 being compressed in booster 2 and is then directed through the main heat exchanger 6.
  • Part 4 is compressed in a booster 2A coupled to a turbine which feeds part of the air to the low pressure column 23.
  • product streams at cryogenic temperatures such as gaseous nitrogen 21 and gaseous oxygen 16 exchange heat with the compressed feed air stream 3.
  • the gaseous oxygen stream 16 is warmed into gaseous oxygen stream 18 for export from the system.
  • the compressed, gaseous inlet air stream 3 is refrigerated to form stream 7 as it transfers its heat to the gaseous oxygen stream and to the gaseous nitrogen stream.
  • the gaseous air stream 7 is either introduced entirely into the Medium Pressure (MP) distillation column 24 as shown in Figure 1 or is split into two streams whereby part of the stream is directed into the MP distillation column and part of the stream is directed into the LP distillation column following expansion in a turbine (not shown).
  • MP Medium Pressure
  • This feed air is separated into its basic components in the MP distillation column 24.
  • An oxygen enriched liquid stream 11 is removed from the bottom of the MP column and a nitrogen enriched liquid stream 12 is extracted from the top of the MP distillation column and directed toward a reflux subcooler 13.
  • reflux is known to be necessary for mass transfer to occur in any distillation column.
  • "Reflux” in any distillation column is the liquid falling downward through the column.
  • the reflux stream sent to a point in a column must generally have a concentration of heavier components (oxygen in the instant case) which is in equilibrium with the vapor which is rising through the column at that point.
  • oxygen in the instant case oxygen in the instant case
  • the composition of the liquid and vapor will come to equilibrium.
  • an essentially oxygen free stream i.e. reflux stream
  • the heavy components present in the rising vapor stream are transferred to the descending liquid stream. This yields high concentrations of heavy components at the bottom of the column and low concentrations of heavy components at the top of the column.
  • the oxygen rich stream 11 and the nitrogen rich stream 12 exchange heat with the "nearly pure" gaseous nitrogen stream 20 that is being withdrawn from the top of the LP distillation column 23.
  • liquid nitrogen has a saturation temperature of -196°C
  • liquid oxygen has a saturation temperature of -183°C
  • liquid nitrogen has a saturation temperature of - 180°C
  • liquid oxygen has a saturation temperature of -143°C.
  • the gaseous nitrogen 20 that is being withdrawn from the top of the LP distillation column 23 is at a lower pressure than the nitrogen rich reflux stream 12, which means that the reflux line 12 can be subcooled considerably by stream 20.
  • ASU air separation unit
  • the subcooled nitrogen enriched stream 15 is introduced into the top of the LP distillation column 23.
  • the pressure of the medium pressure, subcooled reflux is reduced through a pressure reduction valve, the Joule-Thompson expansion further reduces the temperature and increases the degree of subcooling of the reflux stream.
  • the oxygen enriched stream 11 is also subcooled in the reflux subcooler 13 and introduced into the LP distillation column 23 as stream 14.
  • the "nearly pure" nitrogen stream 20 temperature increases slightly in the reflux subcooler due to the heat transfer to the reflux streams 12 and 11.
  • this gaseous nitrogen stream 21 passes through the main heat exchanger 6, where it is warmed due to the heat transfer to the feed air stream. It is then exported as low-pressure gaseous nitrogen product 22.
  • the other main product of this second distillation process is a "nearly pure" oxygen stream 16 which is withdrawn as gas near the bottom of the LP distillation column 23.
  • This gaseous oxygen is very near its saturation temperature, so it is superheated in the main heat exchanger 6. Since the primary design goal of the classic gas cycle is to produce gaseous oxygen at a useable pressure, the pressure of this stream is increased by means of an oxygen compressor 17. It is then exported as high-pressure gaseous oxygen product 19.
  • specific power is defined as the total plant electrical utilization divided by the net volume of gaseous oxygen generated. Typically, this criteria is expressed in units of kW (electrical power) divided by Nm 3 (volumetric flowrate). This can be viewed as an indication of overall plant efficiency, with a more efficient plant having lower specific power.
  • the main disadvantage of the classical gas cycle is a higher overall capital equipment cost.
  • Another disadvantage of this cycle is a higher degree of cycle complexity, and associated with this complexity is a higher maintenance cost and a lower reliability.
  • the advantage of this cycle is a generally good specific power.
  • Figure 2 describes a typical classical pumping cycle plant as taught in the prior art.
  • a standard double column is used with a reboiler condenser (not shown) being used to provide heat transfer between the top gas of the MP column 24 and the bottom liquid of the LP column, thereby providing reboil to the LP column and reflux to the MP column.
  • the air 1 compressed in compressor (not shown) is adequately purified, as discussed above for Figure 1, it is then split into two separate streams.
  • the first compressed inlet air stream is compressed in booster 2 and then into two, one part 3 being directed through the main heat exchanger 6, with the other stream 22 passing through the secondary booster 4.
  • This second, more highly compressed, compressed inlet air stream 5 is then directed through the main heat exchanger 6, and hence adds any additional heat that may be required for the oxygen vaporization balance.
  • this intermediate pressure, compressed inlet air stream 5 is further split into separate streams, with one of these streams being further compressed, as required for energy input to the oxygen vaporization process ( see e.g., US-A- 5735142 ). This step is not indicated on Figure 2.
  • Refrigeration is provided by stream 4 which is boosted in 2A and expanded in turbine 5 as described in Figure 1.
  • a liquid product stream at cryogenic temperatures such as liquid oxygen 18 exchanges heat with the two compressed inlet air streams 3 and (5). Phase change takes place in this oxygen stream and in air stream 5, if their pressures are not supercritical.
  • the liquid oxygen stream 18 is vaporized into a gaseous oxygen stream 19, which is then exported as product for sale. Simultaneously, the compressed, gaseous inlet air streams 7 and 8 transfer their latent and sensible heat to the liquid oxygen stream.
  • the liquid air stream 8 is either introduced entirely into the Medium Pressure (MP) distillation column 24 following expansion in a valve or a hydraulic turbine, introduced entirely into the Low Pressure (LP) distillation column 23 following expansion in a valve or a hydraulic turbine, or is split into two streams whereby part of the stream (9) is directed into the MP distillation column and part of the stream (10) is directed into the LP distillation column following expansion steps for each stream in a respective valve or hydraulic turbine.
  • the air stream, if any, sent to the low pressure column is subcooled before expansion in the reflux subcooler 13.
  • Gaseous stream 7 is directed to the MP distillation column. This air is separated into its basic components in the MP distillation column (24).
  • the vapor which is richer in volatile components, which in this case would be the nitrogen component, rises to the top of the distillation column.
  • the liquid which is richer in less volatile components, which in this case would be the oxygen component, falls to the base of the distillation column.
  • An oxygen enriched stream 11 and a nitrogen enriched stream 12 are extracted from the MP distillation column 24 as described in Claim 1 and directed toward a reflux subcooler 13. The function served by, and the benefits derived from the reflux subcooler are discussed above with respect to Figure 1.
  • the subcooled liquid reflux stream 15 is introduced into the top of the LP distillation column 23.
  • the oxygen rich bottom stream 11 is also subcooled in the reflux subcooler 13 and introduced into the LP distillation column 23 as liquid stream 14.
  • a "nearly pure" nitrogen stream 20 is withdrawn from the top of the LP distillation column 23. It then passes through the reflux subcooler 13, where the temperature of the stream increases slightly due to the heat transfer to the streams 12 and 11. Next this gaseous nitrogen stream 21 passes through the main heat exchanger 6. It is then exported as low-pressure gaseous nitrogen product 22.
  • the other main product of this second distillation process is an oxygen stream 16 which is withdrawn at the base of the LP distillation column 23 containing at least 70 mol. % oxygen. If so desired, LP liquid oxygen can be withdrawn from the cycle at this point 26.
  • the classic pumping cycle produces little if any liquid oxygen product, and only withdraws liquid oxygen to place in storage for backup purposes. Since the primary design goal of the classic pumping cycle is to produce relatively high-pressure gaseous oxygen, the pressure of this low-pressure liquid is increased significantly by means of a cryogenic pump 17.
  • This high-pressure liquid oxygen stream 18 then passes through the main heat exchanger 6, where it is vaporized due to the heat transfer to the inlet air streams. It is then exported as high-pressure gaseous oxygen product 19.
  • the main advantage of this type of process is its ability to produce pressurized oxygen without an oxygen compressor.
  • Another advantage is its operational flexibility in terms of liquid production.
  • the classical pumping cycle generally has no unwanted liquid oxygen product at all.
  • unwanted liquid oxygen product is defined as the amount of liquid product that is produced by a given process, as a function of the design itself. Whether or not such liquid product is desirable, this amount of liquid product cannot be avoided, and is simply a necessary byproduct of that particular chosen process.
  • the classical pumping cycle also has a generally good specific power.
  • the classical pumping cycle has no pronounced disadvantages or advantages.
  • This cycle will have a higher overall capital equipment cost than an offset knee cycle (see below), yet will have a lower overall capital equipment cost than a classical gas cycle.
  • This cycle will have a higher degree of cycle complexity than an offset knee cycle (see below), yet will have a lower degree of cycle complexity than a classical gas cycle.
  • This cycle will have a higher specific power requirement than a GOK cycle (see below), yet will have a lower specific power requirement than a classical gas cycle.
  • the offset knee cycle again there is a heat exchanger that transfers heat from the feed air to the liquid oxygen.
  • all the feed air is compressed to the pressure required to vaporize the oxygen, rather than just part of the stream, and also to a lower pressure than in the cycle above.
  • a second air booster may typically operate at 21 bar or less
  • the air booster or last stage of the main compressor may typically operate at between 21 bar and 41 bar.
  • Figure 3 describes a typical offset knee cycle plant as taught in the prior art.
  • the inlet air 1 is compressed in compressor 2 to a pressure considerably higher than the medium pressure and generally between 21 and 41 bar, it is then purified, as discussed above for Figure 1
  • This high pressure, compressed inlet air stream 3 is directed through the main heat exchanger 6. Within the main heat exchanger, this high pressure stream is split into two separate streams. The first high pressure stream 7 continues through the heat exchanger, and the other high pressure, compressed inlet air stream 4 is removed from an intermediate point of the heat exchanger and directed toward an expander 5. The amount of high pressure air 4 that is withdrawn is determined by the requirement for the oxygen vaporization and refrigeration balance.
  • the air booster (see 4 in Figure 2) may typically operate at between 5.5 and 21 bar, in the offset knee cycle, the air booster or the final stage of compressor 2 may typically operate at above 21 bar ( see e.g ., US.-A-5329776 ).
  • product streams at cryogenic temperatures such as gaseous nitrogen 21 and liquid oxygen 18 exchange heat with the compressed inlet air streams 3,5. Phase changes may take place in streams 18 and 3 depending on whether the pressures are supercritical or not.
  • the gaseous nitrogen steam 21 is warmed and the liquid oxygen stream 18 is vaporized into a gaseous oxygen stream 19, both of which may then be exported as products for sale, or used to precool the air before entering exchanger 6.
  • the compressed, gaseous inlet air stream is cooled 7 as it transfers its latent and sensible heat to the liquid nitrogen and liquid oxygen streams.
  • the gaseous air stream 7 is either introduced entirely into the Medium Pressure (MP) distillation column 24, introduced entirely into the Low Pressure (LP) distillation column 23, or is split into two streams as shown whereby part of the stream 9 is directed into the MP distillation column and part of the stream 10 is directed into the LP distillation column as reflux, following subcooling of the stream 10 in subcooler 13.
  • MP Medium Pressure
  • LP Low Pressure
  • This gaseous or two phase air is separated into its basic components in the MP distillation column 24.
  • An oxygen enriched bottom stream 11 is removed from the bottom of the medium pressure column and a nitrogen enriched reflux stream 12 is extracted from the top of the MP distillation column and both are directed toward a reflux subcooler (13).
  • the function served by, and the benefits derived from, the reflux subcooler are discussed above with respect to Figure 1.
  • the subcooled nitrogen enriched stream 15 is introduced into the LP distillation column 23.
  • the oxygen enriched bottom stream 11 is also subcooled in the reflux subcooler 13 and this subcooled stream 14 introduced into the LP distillation column 23.
  • a "nearly pure" nitrogen stream 20 is withdrawn from the top of the LP distillation column 23. It then passes through the reflux subcooler 13, where the temperature of the stream increases slightly due to the heat transfer to the reflux streams 11 and 12. Next this gaseous nitrogen stream 21 passes through the main heat exchanger 6, where it is warmed due to the heat transfer to the inlet air stream. It is then exported as low-pressure gaseous nitrogen stream 22.
  • the other main product of this second distillation process is a "nearly pure" oxygen stream 16 which is withdrawn at the base of the LP distillation column 23. If so desired, LP liquid oxygen can be withdrawn from the cycle at this point 26.
  • a typical offset knee cycle exports approximately 20 % to 25 % of the total oxygen production in the form of liquid oxygen product.
  • the primary design goal of this cycle is to produce liquid, and the pressure of this low pressure liquid is increased significantly by means of a cryogenic pump 17.
  • This high-pressure liquid oxygen stream 18 then passes through the main heat exchanger 6, where it is vaporized due to the heat transfer to the inlet air stream. It is then exported as high-pressure gaseous oxygen product 19.
  • a disadvantage of this type of process is the reduced operational flexibility in terms of liquid production. This is due to the significant amount of unwanted liquid oxygen product that is produced. Depending on the process parameters of the particular cycle, a typical offset plant will produce between 5 % to 40 % of the gaseous oxygen produced unwanted liquid oxygen product. In the current state of the art, it is impossible to design a typical offset knee plant that produces little or no unwanted liquid oxygen product.
  • the process may comprise expanding at least part of the oxygen enriched liquid to form an expanded oxygen enriched fluid and sending at least part of the expanded oxygen enriched fluid to the low pressure column wherein the oxygen enriched fluid sent into the low pressure column contains at least 13 %, preferably at least 13,5 %, more preferably at least 14,5%, still more preferably at least 16% gas.
  • the nitrogen enriched liquid is sent directly from the medium pressure column to the expanding means.
  • the nitrogen enriched liquid may be removed from the top or an intermediate region of the medium pressure column.
  • the installation comprises means for sending at least part of the oxygen enriched liquid directly or indirectly to the low pressure column and expanding means for expanding the oxygen enriched liquid upstream of the low pressure column.
  • the installation comprises
  • the unit may comprise an intermediate pressure column, means for feeding the intermediate pressure column with oxygen enriched liquid from the medium pressure column and means for feeding fluids from the intermediate pressure column to the low pressure column.
  • the invention can be used in a variety of cycles, for a variety of productions of liquids and gases, and at a variety of temperatures and pressures.
  • the following explanations are examples of some of the uses of this invention, and are not meant to be limiting in any way.
  • the compressed inlet air 1 is purified, it is divided into two streams.
  • One stream is boosted in booster 2A and then expanded in turbine 5 before being sent to the low pressure column.
  • Other additional or alternative means of providing refrigeration may be envisaged, such as a Claude turbine.
  • the rest of the air is compressed in booster 2 to the pressure of the medium pressure column (at least 5,5 bar) and then split into two separate streams 3,22.
  • two separate compressors may be used without splitting the inlet air into two streams.
  • the first compressed inlet air stream 3 is directed through the main heat exchanger 6, with the other stream 22 passing through the secondary compressor 4.
  • This second, more highly compressed inlet air stream 5 is then directed through the main heat exchanger 6, and hence adds any additional heat that may be required for the oxygen vaporization balance.
  • this intermediate pressure, compressed inlet air stream 5 is further split into separate streams, with one of these streams being further compressed, as required for energy input to the oxygen vaporization process.
  • a liquid stream at cryogenic temperatures such as liquid oxygen 18 exchanges heat with the two compressed inlet air streams 3 and 5. Phase changes may takes place in stream 5 if the pressure is subcritical.
  • the liquid oxygen stream 18 is vaporized into a gaseous oxygen stream 19, which is then exported as product for sale. Simultaneously, the compressed, gaseous inlet air stream is cooled 8 as it transfers its latent and sensible heat to the liquid oxygen stream.
  • the air stream 8 may be introduced entirely into the Medium Pressure (MP) distillation column 24 in mainly liquid form, introduced entirely into the Low Pressure (LP) distillation column 23 in mainly liquid form, or is split into two streams whereby part of the stream 9 is directed into the MP distillation column and part of the stream 10 is directed into the LP distillation column both in mainly liquid form as shown.
  • the compressed stream 10, typically between 40 et 60 % of stream 8 is subcooled in reflux subcooler 13 against gaseous nitrogen 20 and then passes through a pressure reduction valve 31 before entering the low pressure column 23 containing at least 1,6 %, preferably at least 1,7 % and/or at most 15 %, preferably at most 5 % gas. It is important to avoid introducing too much air as flash gas.
  • the gaseous and mainly liquid air 25, 9 is separated into its basic components in the MP distillation column 24.
  • An oxygen enriched liquid stream 11 is withdrawn from the bottom of the MP column 24 and a nitrogen enriched liquid stream 12 is extracted from the top of the MP distillation column.
  • These streams are conveyed to the LP column by means of an operating pressure differential across a valve or a dense fluid expander between the HP and LP column.
  • the subcooler 13 can form part of the heat exchanger 6.
  • the oxygen rich stream 11 passes through a pressure reduction valve 27 upstream of the LP column and the nitrogen rich stream 12 also passes through a pressure reduction valve 28 or other such apparatuses or devices known to one skilled in the art.
  • the reflux stream 15, which has not been cooled by any step other than the expansion step in valve 28, is introduced into the LP distillation column 23 containing substantially 17 % gas.
  • the oxygen rich bottom stream 11, which has not been cooled by any step other than the expansion step in valve 27, is introduced into the LP distillation column 23 at an intermediate level containing substantially 17 % gas.
  • a "nearly pure" nitrogen stream 20 is withdrawn from the top of the LP distillation column 23 and cools the air stream 8 upstream of valve 29.
  • the expanded air is then sent to the low pressure column 23 in at least mostly liquid form.
  • this gaseous nitrogen stream 21 passes through the main heat exchanger 6. It is then exported as low-pressure gaseous nitrogen product 22.
  • the other main product of this second distillation process is a oxygen stream 16 containing at least 70 mol. % oxygen which is withdrawn at the base of the LP distillation column 23. If so desired, LP liquid oxygen 26 can be withdrawn from the cycle at this point as a final product.
  • the classic pumping cycle produces little if any liquid oxygen product, and only withdraws liquid oxygen to place in storage for backup purposes. Since the primary design goal of the classic pumping cycle is to produce relatively high-pressure gaseous oxygen, the pressure of this low-pressure liquid is increased significantly by means of a cryogenic pump 17.
  • This high-pressure liquid oxygen stream 18 then passes through the main heat exchanger 6, where it is vaporized due to the heat transfer to the inlet air streams. It is then exported as high-pressure gaseous oxygen product 19.
  • the-inlet air purification phase is typical and common to all cryogenic air separation systems, and is therefore not indicated on Figure 5.
  • the inlet air enters the cycle at ambient conditions.
  • This inlet air is compressed in the main air compressor to a pressure higher than the medium pressure and then purified.
  • the compressed air passes through a series of intercoolers, aftercoolers and/or a chilling system cooled to reduce the water vapor in the process air (not shown).
  • the chilling can be done by either a refrigeration system or a direct contact aftercooler, which exchanges heat between the warm inlet air and water which is in turn chilled by gaseous nitrogen which is produced in the air separation cycle.
  • adsorbers can be of the horizontal bed or radial bed design, and typically contain (at least) two types of adsorbents.
  • One adsorbent typically activated alumina, will dry the air and simultaneously remove any acids present.
  • the other adsorbent typically a molecular sieve, will remove carbon dioxide, methane and some of the other hydrocarbons which are present.
  • These adsorbers are typically regenerated on-line, and thus (at least) two trains will be required for continuous operation.
  • the inlet air is passed through a particle filter which is located either inside of or immediately after the adsorber vessels and used to remove fine dust particles and any other particulate contaminants.
  • the pressurized air typically leaves this system at a pressure of approximately 15 to 30 bar, and a temperature of 15 to 30°C.
  • the inlet air passes through another compressor 2.
  • this compressor typically raises the inlet air pressure to approximately 20 to 30 bar (intermediate pressure), and raises the temperature to approximately 35 to 50°C.
  • This intermediate pressure, compressed inlet air stream (3) is then directed through the main heat exchanger 6.
  • the main heat exchanger is typically of brazed aluminum construction but may also be a shell in tube type or other such exchangers known to one skilled in the art, and utilizes a countercurrent flow.
  • this intermediate pressure stream is split into two separate streams. The first intermediate pressure stream 7 continues through the heat exchanger. Approximately 15 to 30 % of the inlet air mass flowrate flows through this stream 7, which provides the heat required to vaporize the high-pressure liquid oxygen stream 18.
  • the other intermediate pressure, compressed inlet air stream 4 is removed from an intermediate point of the heat exchanger and directed toward an expander 5.
  • separate streams may be used with or without separate compressors, rather than splitting the compressed air into two streams.
  • the amount of intermediate pressure air that is withdrawn 4 is determined by the requirement for the oxygen vaporization balance. Approximately 70 to 85 % of the inlet air mass flowrate flows through this stream 4, from which the booster 2 consumes approximately 95 % of the power generated by the associated expander 5.
  • the process air 25 leaves the expander 5 with a pressure of approximately 4.5 to 6.5 bar, and a temperature of approximately -170°C to - 175°C.
  • the process air leaving the expander 5 may be comprised of a two-phase flow, of which approximately 5 to 15 % is vapor phase or may be entirely gaseous (See e.g. US-A-5329776 ).
  • product streams are present at cryogenic temperatures.
  • the gaseous nitrogen stream 21 has a pressure of approximately 1.2 to 2 bar, and a temperature of approximately -190 to -193°C.
  • the liquid oxygen stream 18 has a pressure which can range from 20 to 80 bar, and a temperature of approximately -170 to -178°C. These streams exchange heat with the compressed inlet air stream 3. Phase changes may take place in stream 3.
  • the gaseous nitrogen steam 22 is warmed to a temperature of approximately 10 to 40°C at the warm end of exchanger 6.
  • the liquid oxygen stream 18 is vaporized into a gaseous oxygen stream 19, which typically has a temperature of approximately 10 to 40°C at the warm end of exchanger 6. Both of these streams are then exported as products for sale.
  • the compressed gaseous inlet air stream is cooled 7 as it transfers its latent heat to the liquid oxygen stream.
  • This liquefied process air stream typically has a pressure of approximately 20 to 30 bar, and a temperature of approximately -185 to -191°C.
  • the intermediate pressure air stream 7 as shown is at least directed to the Low Pressure (LP) distillation column 23, now as stream 10 as required to maintain optimum reflux ratios in the lower sections of the MP and LP distillation columns 23 and 24. As shown it may be split into two streams with one stream 10 introduced into the LP distillation column 23 and the rest 9 to the MP column. Otherwise it may be sent in its entirety to the MP column 24. At least 40% 10 of the stream 7 is sent to the low pressure column containing at least 1,6 %, preferably at least 1,7 % and/or at most 15%, preferably at most 5 %.
  • LP Low Pressure
  • the stream 10 contains at least 1,6 %, preferably at least 1,7 % and/or at most 15%, preferably at most 5% gas at the point of injection into column 23.
  • the compressed stream 10 is first subcooled in reflux subcooler 13 and then passes through a pressure reduction valve 31 before entering the low pressure column 23.
  • Stream 10 is the only stream which exchanges heat with stream 20 upstream of the exchanger 6.
  • the two-phase or gaseous process air stream leaving the expander 5 is directed to the MP distillation column 24.
  • This liquid and gaseous air 9, 25 is separated into its basic components in the MP distillation column 24.
  • the MP distillation column typically operates at a pressure that ranges from 4.5 bar to 6.5 bar but may operate at higher pressures.
  • An oxygen enriched liquid stream 11 is removed from the bottom of the MP column and a nitrogen rich reflux stream 12 is extracted from the top of the MP distillation column 24 and directed toward the LP distillation column 23 as reflux streams. These streams are conveyed to the LP column by means of an operating pressure differential across a valve or dense fluid expander 27, 28 between the HP column and the LP column.
  • the oxygen rich bottom stream 11 has a pressure of approximately 4.5 to 6.5 bar, a temperature of approximately - 170 to -175°C, and a composition of approximately 61.3 % nitrogen, 37.4 % oxygen, and 1.3% argon (mole fraction), preferably containing between 25 and 50 % oxygen.
  • the nitrogen rich reflux stream 12 has a pressure of approximately 4.5 to 6.5 bar, a temperature of approximately -175 to -180°C, and a composition of typically > 99 % nitrogen .
  • the oxygen enriched stream 11 passes through a pressure reduction valve 27, dense fluid expander, or other such devices or apparatuses known to one skilled in the art for reducing pressure, after which the oxygen enriched stream 14 pressure is approximately 1.2 to 2 bar and the temperature is approximately -185 to -190°C containing substantially 17 % gas.
  • the nitrogen rich stream 12 also passes through a pressure reduction valve 28, dense fluid expander or other such devices or apparatus known to one skilled in the art for reducing pressure, after which the reflux stream 15 pressure is approximately 1.2 to 2 bar and the temperature is approximately -190 to -193°C containing substantially 17% gas.
  • a pressure reduction valve 28 dense fluid expander or other such devices or apparatus known to one skilled in the art for reducing pressure
  • the reflux stream 15 pressure is approximately 1.2 to 2 bar and the temperature is approximately -190 to -193°C containing substantially 17% gas.
  • the Joule-Thompson expansion further cools the reflux stream.
  • Figure 5 uses a subcooler only to cool the feed air stream 10. It is also possible to subcool only part of stream 10.
  • the subcooler 13 can form part of the heat exchanger 6.
  • the system actually is capable of transferring approximately 1.7 % more heat within the system. This is due to the fact that the reflux subcooler is typically of a less efficient cross-current design, and the main heat exchanger is typically of a more efficient counter-current design. This reduction, or elimination, of the reflux subcooler 13, and the associated piping will result in a substantially lower overall capital equipment cost.
  • a "nearly pure” nitrogen stream 20 is withdrawn from the top of the LP distillation column (23).
  • This "nearly pure” nitrogen stream (20) typically has a composition of approximately 98.2 % nitrogen, 0.7 % oxygen, and 1.1 % argon (mole fraction), but may be of another composition considered to be nearly pure by one skilled in the art, for example at least 90 % mol. It also likely has a pressure of approximately 1.2 to 2 bar, a temperature of approximately -190 to -193°C.
  • This stream 20 then passes through the main heat exchanger 6, where it is warmed due to the heat transfer to the inlet air stream. It is then exported as low-pressure gaseous nitrogen product 22.
  • This low-pressure gaseous nitrogen product stream 22 has a pressure of approximately 1.0 to 1.5 bar, and a temperature of approximately 10 to 40°C.
  • the other main product of this second distillation process is a "nearly pure" oxygen stream 16 which is withdrawn at the base of the LP distillation column 23.
  • This "nearly pure" oxygen stream 16 typically has a composition of approximately 95 % to 99.8 % oxygen, but may be of another composition considered to be nearly pure by one skilled in the art, such as at least 70 %. It also likely has a pressure of approximately 1.2 to 2 bar, a temperature of approximately -179°C, and if so desired, for either backup purposes or for sale as a product, this low-pressure liquid oxygen can be removed from the system at this point. In this embodiment, 0 to 30 % of the liquid oxygen that is leaving the LP distillation column 16, is removed as liquid oxygen product 26.
  • the high-pressure gaseous oxygen product stream 19 has pressure range of 20 to 80 bar, and a temperature of approximately 10 to 40°C.
  • Figure 7 is based on Figure 4 and differs therefrom in that the oxygen enriched liquid stream 11 is divided in two parts, in any desired proportions. Part 11 A is not cooled but the rest 11B is subcooled in subcooler 13 with air stream 10 by heat exchange with stream 20. The two streams 11A, 11B are then mixed, expanded in valve 27 to form stream 14 which enters the middle of the low pressure column 23 containing between 13 and 17% gas. The proportion of gas in stream 14 will be less than in the case of Figure 4 but the subcooler will be smaller. The subcooler 13 can form part of the heat exchanger 6. Stream 17 contains substantially 17% gas.
  • Figure 8 is based on Figure 5 and differs therefrom in that the nitrogen enriched liquid stream 12 is divided in two parts, in any desired proportions.
  • Part 12 A is not cooled but the rest 12B is subcooled in subcooler 13 with air stream 10 by heat exchange with stream 20.
  • the two streams 12A, 12B are then mixed, expanded in valve 28 to form stream 15 which enters the top of the low pressure column 23 containing between 13 and 17% gas.
  • the proportion of gas in stream 15 will be less than in the case of Figure 5 but the subcooler will be smaller.
  • the subcooler 13 can form part of the heat exchanger 6.
  • Stream 14 contains substantially 17 % gas.
  • the partial cooling of Figures 7 and 8 may also be achieved by using a underdimensioned subcooler to cool all of the rich liquid 11 and/or the liquid air 10 and/or the pure liquid 12, the result being that the cooled reflux liquids are less cold than those of the prior art and consequently contain more flash gas following expansion.
  • the air stream which has served to vaporize a liquid stream and is then expanded in valve 31 enters column 23 containing at least 1,6 %, preferably at least 1,7 % and/or at most 15 %, preferably at most 5 % gas.
  • This third distillation column can be an intermediate pressure column for the distillation of air or a gas derived from air such as the rich liquid.
  • an air separation plant incorporating three or more distillation columns, coupled with an argon distillation column can be improved by way of this invention, by the partial or complete removal of the reflux subcooler.
  • the reflux subcooler is completely removed from these systems.
  • these systems include at least one cryogenic pump for pumping liquid oxygen and/or nitrogen to be vaporized in the exchanger 6.
  • a classical gas cycle installation will typically have a total capital cost that is higher than classical pumping cycle.
  • a classical pumping cycle installation will typically have a total capital equipment cost that is higher than an offset knee cycle.
  • the classical gas cycle there is typically a large oxygen compressor, and often a large nitrogen compressor as well. These typically operate at moderate to high pressure.
  • the classical pumping cycle configuration there are a greater number of large pieces of rotating equipment, typically operating at higher pressure.
  • the rotating equipment capital cost for a typical classical gas cycle installation will be higher than that of a classical pumping cycle plant of identical output.
  • the rotating-equipment capital cost for a typical classical pumping cycle installation will be higher than that of an offset knee plant of identical output. In either type of plant, the capital cost of the rotating equipment is approximately one half of the total capital cost of the plant.
  • the reflux subcooler was previously considered to be essential for the proper functioning of the distillation columns.
  • the present invention takes the step of removing this reflux subcooler from or reducing this reflux subcooler in any air separation process in which pumped cryogenic liquid is vaporized by heat exchange with a calorigenic fluid.
  • a classic gas plant and a pumping cycle plant, in that the liquid air that is leaving the main heat exchanger in a pumping cycle plant may even be sufficiently subcooled, from having exchanged its heat to superheat the high pressure liquid oxygen, as to provide adequate subcooling to the LP distillation column in the absence of any reflux subcooler.
  • the removal of the reflux subcooler and all the associated interconnecting piping and instrumentation has only a very small impact on the total oxygen recovery when applied to a pumping cycle, as shown in Figure 6.
  • This invention offers over the prior art is that it greatly simplifies either the classical pumping cycle or the offset knee cycle, by removing or reducing the reflux subcooler and all the associated interconnecting piping and instrumentation, thereby significantly reducing the total capital cost, as well as the total installed cost and overall maintenance cost.
  • This invention can also be utilized to incorporate a syngas plant in the typical GTL or methanol plant in a remote location, by providing high-pressure oxygen in a less complicated plant which is more reliable, and hence less expensive to maintain.
  • the air separation unit component is typically 15 % to 20 % of the total capital investment.
  • the use of this invention in a pumping cycle offers significant capital cost and maintenance cost advantages.
  • the table shows the percentage of vapor after the pressure reducing valves 27, 28, 31 for the three reflux streams 10,14,15.
  • the air stream or the partial reflux streams may be subcooled against a single nitrogen enriched stream from the low pressure column, which may the top stream as shown or an intermediate stream or against several nitrogen enriched streams from the low pressure column.
  • the air separation unit may produce nitrogen rich fluids of different purities from the low pressure column and in this case nitrogen enriched liquid having two different purities may be sent from the medium pressure column to the low pressure columns.
  • nitrogen enriched liquid having two different purities may be sent from the medium pressure column to the low pressure columns.
  • One or both of these streams may be either not subcooled or only partially subcooled before being sent to the low pressure column.
EP03075304A 2002-01-31 2003-01-31 Procédé et installation pour la séparation d'air par distillation cryogénique Withdrawn EP1338856A3 (fr)

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CN112781321A (zh) * 2020-12-31 2021-05-11 乔治洛德方法研究和开发液化空气有限公司 一种具有氮液化器的空气分离装置和方法
CN112969896A (zh) * 2018-10-26 2021-06-15 乔治洛德方法研究和开发液化空气有限公司 板翅式热交换器组件
EP4209744A1 (fr) 2022-01-07 2023-07-12 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Echangeur de chaleur et appareil de séparation comportant un échangeur de chaleur

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EP1094287A2 (fr) * 1999-10-22 2001-04-25 The BOC Group plc Séparation d'air
EP1099922A2 (fr) * 1999-11-09 2001-05-16 Air Products And Chemicals, Inc. Procédé de la production d'oxygène de pression intermédiaire
EP1310753A1 (fr) * 2001-11-10 2003-05-14 Messer AGS GmbH Procédé et dispositif pour la séparation cryogénique d'air

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EP1094287A2 (fr) * 1999-10-22 2001-04-25 The BOC Group plc Séparation d'air
EP1099922A2 (fr) * 1999-11-09 2001-05-16 Air Products And Chemicals, Inc. Procédé de la production d'oxygène de pression intermédiaire
EP1310753A1 (fr) * 2001-11-10 2003-05-14 Messer AGS GmbH Procédé et dispositif pour la séparation cryogénique d'air

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Publication number Priority date Publication date Assignee Title
CN112969896A (zh) * 2018-10-26 2021-06-15 乔治洛德方法研究和开发液化空气有限公司 板翅式热交换器组件
CN112969896B (zh) * 2018-10-26 2023-05-02 乔治洛德方法研究和开发液化空气有限公司 板翅式热交换器组件
CN112781321A (zh) * 2020-12-31 2021-05-11 乔治洛德方法研究和开发液化空气有限公司 一种具有氮液化器的空气分离装置和方法
CN112781321B (zh) * 2020-12-31 2022-07-12 乔治洛德方法研究和开发液化空气有限公司 一种具有氮液化器的空气分离装置和方法
EP4209744A1 (fr) 2022-01-07 2023-07-12 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Echangeur de chaleur et appareil de séparation comportant un échangeur de chaleur
FR3131775A1 (fr) 2022-01-07 2023-07-14 L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Echangeur de chaleur et appareil de séparation comportant un échangeur de chaleur

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