EP3757493A1 - Procédé et installation d'obtention d'un produit dérivé de l'air riche en azote et riche en oxygène au moyen d'un fractionnement à basse température de l'air - Google Patents

Procédé et installation d'obtention d'un produit dérivé de l'air riche en azote et riche en oxygène au moyen d'un fractionnement à basse température de l'air Download PDF

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Publication number
EP3757493A1
EP3757493A1 EP19020402.4A EP19020402A EP3757493A1 EP 3757493 A1 EP3757493 A1 EP 3757493A1 EP 19020402 A EP19020402 A EP 19020402A EP 3757493 A1 EP3757493 A1 EP 3757493A1
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Prior art keywords
pressure
air
liquid
pressure column
condenser
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EP19020402.4A
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German (de)
English (en)
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Tobias Lautenschlager
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Linde GmbH
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Linde GmbH
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
    • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
    • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
    • F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
    • F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
    • F25J3/0423—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
    • F25J3/04006—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
    • F25J3/04248—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
    • 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
    • F25J2200/00—Processes or apparatus using separation by rectification
    • F25J2200/50—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the column
    • F25J2200/54—Processes or apparatus using separation by rectification using multiple (re-)boiler-condensers at different heights of the column in the low pressure column of a double pressure main column system
    • 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
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/40—Processes or apparatus using other separation and/or other processing means using hybrid system, i.e. combining cryogenic and non-cryogenic separation techniques
    • 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
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/60—Processes or apparatus using other separation and/or other processing means using adsorption on solid adsorbents, e.g. by temperature-swing adsorption [TSA] at the hot or cold end
    • 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
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/80—Processes or apparatus using other separation and/or other processing means using membrane, i.e. including a permeation step
    • 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
    • F25J2215/40—Air or oxygen enriched air, i.e. generally less than 30mol% of 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
    • F25J2235/00—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams
    • F25J2235/42—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams the fluid 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
    • 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

Definitions

  • the present invention relates to a method and a system for obtaining a nitrogen-rich air product and an oxygen-rich air product using a low-temperature decomposition of air according to the preambles of the independent claims.
  • Air separation plants have rectification column systems which can conventionally be designed as two-column systems, in particular as classic Linde double-column systems, but also as three- or multi-column systems.
  • rectification columns for obtaining nitrogen and / or oxygen in liquid and / or gaseous state, i.e. the rectification columns for nitrogen-oxygen separation
  • rectification columns can be provided for obtaining further air components, in particular the noble gases krypton, xenon and / or argon.
  • the terms “rectification” and “distillation” and “column” and “column” or terms composed of these are often used synonymously.
  • the rectification columns of the mentioned rectification column systems are operated at different pressure levels.
  • Known double column systems have a so-called high pressure column (also referred to as a pressure column, medium pressure column or lower column) and a so-called low pressure column (also referred to as an upper column).
  • the high pressure column is typically operated at a pressure level of 4 to 7 bar, in particular approx. 5.3 bar.
  • the low pressure column is at a pressure level of typically 1 to 2 bar, in particular about 1.4 bar operated. In certain cases, higher pressure levels can also be used in one or in both rectification columns.
  • the pressures given here and below are absolute pressures at the top of the respective columns given.
  • the present invention therefore has the task of specifying a method and an air separation plant by means of which larger amounts of gaseous nitrogen at a pressure level significantly above atmospheric and at the same time a gaseous, oxygen-rich air product can advantageously be provided.
  • the present invention proposes a method and a system for obtaining a nitrogen-rich air product and an oxygen-rich air product using a low-temperature decomposition of air with the features of the independent patent claims.
  • Refinements of the present invention are the subject of the dependent patent claims and the following description.
  • Liquids and gases can be rich or poor in one or more components in the parlance used here, with “rich” for a content of at least 75%, 90%, 95%, 99%, 99.5%, 99.9% or 99.99% and “poor” can mean a content of no more than 25%, 10%, 5%, 1%, 0.1% or 0.01% on a mole, weight or volume basis.
  • the term “predominantly” can match the definition of "rich”.
  • Liquids and gases can also be enriched or depleted in one or more components, these terms referring to a content in refer to a source liquid or gas from which the liquid or gas was obtained.
  • the liquid or the gas is "enriched” if this or this is at least 1.1 times, 1.5 times, 2 times, 5 times, 10 times 100 times or 1,000 times the content, and " depleted "if this or this contains at most 0.9 times, 0.5 times, 0.1 times, 0.01 times or 0.001 times the content of a corresponding component, based on the starting liquid or the starting gas . If, for example, “oxygen”, “nitrogen” or “argon” is used here, this also includes a liquid or a gas that is rich in oxygen or nitrogen, but does not necessarily have to consist exclusively of these.
  • pressure level and "temperature level” to characterize pressures and temperatures, which is intended to express that corresponding pressures and temperatures in a corresponding system do not have to be used in the form of exact pressure or temperature values to realize the inventive concept.
  • pressures and temperatures typically move in certain ranges, for example ⁇ 1%, 5%, 10% or 20% around a mean value.
  • Corresponding pressure levels and temperature levels can be in disjoint areas or in areas that overlap.
  • pressure levels include, for example, unavoidable or expected pressure losses.
  • temperature levels include, for example, unavoidable or expected pressure losses.
  • the values specified in bar with regard to the pressure levels are absolute pressures.
  • expansion machines “expansion machines” or the like are typically understood to mean known turboexpander. These expansion machines can in particular also be coupled to compressors or boosters. These compressors can in particular be turbo compressors. A corresponding combination of turbo expander and turbo compressor is typically also referred to as a "turbine booster”.
  • turbine booster the turbo-expander and the turbo-compressor are mechanically coupled, the coupling being able to take place at the same speed (for example via a common shaft) or at different speeds (for example via a suitable transmission gear).
  • compressor is generally used here, even if it is a booster coupled with a turboexpander.
  • a “main air compressor” is characterized by the fact that it compresses all of the air that is fed to the air separation plant and separated there. In contrast, in one or more optionally provided further compressors, for example booster compressors, only a portion of this air that has already been previously compressed in the main air compressor is further compressed.
  • the “main heat exchanger” of an air separation plant represents the heat exchanger in which at least the majority of the air supplied to the air separation plant and broken down there is cooled. This takes place at least partly in countercurrent to the material flows that are discharged from the air separation plant. Such "diverted” material flows or “products” are fluids in the parlance used here, which no longer participate in system-internal circuits, but are permanently withdrawn from them.
  • a “heat exchanger” for use in the context of the present invention can be designed in a manner customary in the art. It serves for the indirect transfer of heat between at least two e.g. fluid flows guided in countercurrent to one another, for example a warm compressed air flow and one or more cold fluid flows or a cryogenic liquid air product and one or more warm or warmer, but possibly also cryogenic fluid flows.
  • a heat exchanger can be formed from a single or several parallel and / or serially connected heat exchanger sections, e.g. from one or more plate heat exchanger blocks. It is, for example, a plate heat exchanger (plate fin heat exchanger).
  • Such a heat exchanger has “passages” which are designed as separate fluid channels with heat exchange surfaces and which are connected to form “groups of passages” in parallel and separated by other passages.
  • a heat exchanger is characterized by the fact that heat is exchanged between two mobile media in it at one point in time, namely at least one fluid flow to be cooled and at least one fluid flow to be heated.
  • a “condenser evaporator” is a heat exchanger in which a first, condensing fluid flow enters into indirect heat exchange with a second, evaporating fluid flow.
  • Each condenser evaporator has a liquefaction space and an evaporation space.
  • the liquefaction and evaporation spaces have liquefaction and evaporation passages.
  • the relative spatial terms “above”, “below”, “above”, “below”, “above”, “below”, “next to”, “next to each other", “vertical”, “horizontal” etc. refer to the spatial alignment of the components of an air separation plant in normal operation.
  • An arrangement of two components “one above the other” is understood here to mean that the upper end of the lower of the two components is at a lower or the same geodetic height as the lower end of the upper of the two components and that the projections of the two apparatus parts overlap in a horizontal plane .
  • the two components can be arranged exactly one above the other, i. the axes of the two components perpendicular to the horizontal run on the same vertical straight line.
  • the axes of the two components do not have to be exactly perpendicular, but can also be offset from one another, especially if one of the two components, for example a rectification column or a column part with a smaller diameter, is to have the same distance from the sheet metal jacket of a coldbox as another with a larger one Diameter.
  • the present invention is based on the knowledge that a modification of a conventional air separation plant can be used particularly advantageously to obtain nitrogen at a pressure level as explained above, ie a pressure level of approx. 10 bar or more generally from 7 to 12 bar, and that thus, in an embodiment according to the invention, an oxygen-rich, gaseous air product can also be provided under pressure in a particularly advantageous manner and in different purities.
  • a double column system is used which, in contrast to classic processes or air separation plants, is operated at a higher pressure level or at two higher pressure levels.
  • the corresponding columns of such a double column arrangement are also referred to here as high pressure column and low pressure column, but at least the high pressure column here is operated at a significantly higher pressure level than the high pressure column of a known air separation plant.
  • the invention is based in particular on a method or a corresponding system as they are known from the patent literature mentioned at the beginning.
  • this overhead gas can be withdrawn, which is directly, i.e. can be provided as a nitrogen product at a desired product pressure without further compression.
  • the air separation plant proposed according to the invention or a corresponding method the use of booster compressors for a corresponding nitrogen product or, in principle, also possible internal compression, as is known from the prior art, is unnecessary.
  • an oxygen-rich air product can also be obtained in a gaseous state under pressure.
  • the method proposed according to the invention can in principle also be used to obtain further air products such as liquid oxygen, argon and the like and expanded accordingly.
  • the following explanations relate in particular to the extraction of pressurized, gaseous nitrogen and oxygen or a corresponding nitrogen-rich air product and a corresponding oxygen-rich air product.
  • a known modification of a conventional air separation plant is made to the effect that the high pressure column and the low pressure column are each operated with condenser evaporators which liquefy the top gas of the corresponding columns and return them to them.
  • the so-called main condenser is used to condense overhead gas from the high pressure column, provided that no further columns, such as for argon production, are present.
  • Top gas of the low-pressure column is typically not liquefied in conventional processes because the pressures used are also insufficient for this purpose. Rather, in conventional systems, a return to the low-pressure column is formed exclusively by liquid from the high-pressure column.
  • the gaseous, oxygen-rich air product is formed from liquid which is present in an evaporation space of the condenser-evaporator, which cools and condenses the top gas of the low-pressure column, and which is here generally referred to as the "second" condenser-evaporator.
  • the formation of the gaseous, oxygen-rich air product from this liquid includes an internal compression, as is basically known from the field of air separation.
  • a gaseous, pressurized air product is conventionally formed by removing a cryogenic, liquid air product from the rectification column system, subjecting it to a pressure increase to a product pressure, and heating it to the gaseous or supercritical state at the product pressure.
  • gaseous, pressurized oxygen, gaseous, pressurized nitrogen and / or gaseous, pressurized argon can be generated by means of conventional internal compression.
  • the internal compression offers a number of advantages compared to an alternatively also possible external compression and is explained, for example, by Häring (see above) in Section 2.2.5.2, "Internal Compression".
  • the present invention proposes a method for obtaining a nitrogen-rich air product and an oxygen-rich air product using a low-temperature separation of air in an air separation plant.
  • the air separation plant has a rectification column system with a high pressure column operated at a first pressure level and a low pressure column operated at a second pressure level below the first pressure level. Details on this have already been explained.
  • the rectification column system used according to the invention represents in particular a modification of a conventional double column system.
  • compressed air is cooled and at least fed into the high pressure column.
  • an expansion can take place before the feed, for example in an expansion machine or in an expansion valve.
  • the compressed air can also be at least partially liquefied during cooling, or at least one cooled compressed air flow in a gaseous state and at least one cooled compressed air flow in a liquefied state can be used.
  • the present invention is not limited to specific configurations of the air supply. Some of the compressed compressed air can also be partially cooled and then relaxed, but discharged from the system. In this way, cold can be obtained by heating this relaxed compressed air in a main heat exchanger against compressed air that is later fed into the rectification column system.
  • the high pressure column is operated at a higher pressure level than in conventional systems, so that in the context of the present invention the first pressure level is 7 to 12 bar.
  • the second pressure level is advantageously 3 to 5 bar, so the low-pressure column is also operated at a higher pressure level than is conventionally the case.
  • top gas of the high pressure column can be provided directly as a pressurized nitrogen product which is present at a desired product pressure without recompression.
  • a first condensate is formed in a first condenser evaporator and partially or completely returned to the high pressure column. It is also possible for only part of a corresponding condensate to be returned to the high pressure column and a further part of the condensate to be carried out as a liquid nitrogen product from the air separation plant.
  • a second condensate is formed in a second condenser-evaporator using overhead gas from the low-pressure column and partially or completely returned to the low-pressure column.
  • some of the corresponding liquefied Top gas of the low pressure column can be returned to the high pressure column by means of a pump after liquefaction.
  • All streams of matter used within the scope of the invention or removed from the rectification column system or its two rectification columns or fed into them can be cooled against each other (subcooled), for which purpose corresponding subcoolers (also referred to as subcooling countercurrent) can be used.
  • subcoolers also referred to as subcooling countercurrent
  • Such sub-coolers can also be combined into larger units that subject more than two material flows to a mutual heat exchange with one another.
  • bottom liquid from the low-pressure column is fed into an evaporation space of the second condenser evaporator.
  • Liquid is taken from the evaporation chamber of the second condenser evaporator, subjected to a pressure increase in the liquid state, evaporated or transferred to the supercritical state, and used to provide the oxygen-rich, gaseous air product.
  • a corresponding pressurized oxygen product can also be provided in a particularly advantageous manner in the course of the process optimized for the provision of pressurized nitrogen.
  • the internally compressed material flow or the liquid used to form this material flow from the second condenser evaporator is the only liquid with an oxygen content of more than 40% in a corresponding system, and this can therefore advantageously be used as an oxygen product with or without subsequent further processing will.
  • Typical pressures at which the nitrogen-rich, gaseous pressure product is provided in the context of the present invention are, for example, 7 to 10 bar.
  • the method proposed according to the invention also offers particular advantages, in particular, because in this case the liquid otherwise used to flush the evaporation chamber is released as a gaseous product. Therefore, the cold balance remains essentially unaffected compared to a liquid delivery, so that an amount corresponding to up to 20% of the amount of the nitrogen-rich, gaseous air product can be withdrawn in the form of the oxygen-rich, gaseous air product.
  • the oxygen-rich, gaseous air product is provided in an amount which is 1 to 20% of an amount in which the nitrogen-rich, gaseous air product is provided.
  • the purity of the liquid removed from the evaporation chamber of the second condenser evaporator, subjected to the pressure increase in the liquid state and evaporated or transferred to the supercritical state is sufficient for the intended use, for example for oxygen-enriched combustion, this can be used as the oxygen-rich, gaseous air product can be used.
  • the oxygen content of the liquid from the second condenser-evaporator is, as mentioned, more than 40% oxygen, in particular 60 to 78% oxygen, on a molar basis.
  • the liquid removed from the evaporation chamber of the second condenser evaporator, subjected to the pressure increase in the liquid state and evaporated or transferred to the supercritical state can also be used as the oxygen-rich, gaseous air product already briefly mentioned non-cryogenic oxygen enrichment are subjected.
  • Pressure swing adsorption and / or membrane separation have proven to be particularly advantageous in connection with the measures proposed according to the invention. The reason for this is, in particular, that the liquid taken from the evaporation chamber of the second condenser evaporator, subjected to the pressure increase in the liquid state and evaporated or transferred to the supercritical state is completely free of water and carbon dioxide, which is particularly advantageous for further use in a corresponding process offers.
  • the pressure swing adsorption can in particular be carried out in the form of what is known as vacuum pressure swing adsorption, which is characterized in that a subatmospheric desorption pressure of, for example, 100 to 900 mbar or 200 to 800 mbar is used.
  • the non-cryogenic oxygen enrichment can be done to a level of 80 to 95% on a molar basis if pressure swing adsorption is used, and to a level of 80 to 99.9% on a molar basis if a membrane process is used.
  • a membrane process is particularly advantageous because here the energy required for material separation is withdrawn from the fluid by reducing the pressure (the gradient of the partial pressures of oxygen drives the material separation). Compared to (vacuum) pressure swing adsorption, the devices used in a membrane process are inexpensive, space-saving, low-maintenance and do not generate any additional noise emissions. In addition, the start-up time in a membrane process is very short.
  • Polyimide or poly (p-phenylene oxide), for example, are suitable as membrane material for oxygen separation.
  • the evaporation chamber of the second top condenser can in particular be operated at a pressure level of 1.2 to 2.5 bar.
  • the bottom liquid of the low-pressure column is therefore expanded from the second pressure level to this pressure level before being fed into the evaporation space, and the liquid is withdrawn from the evaporation space at this pressure level.
  • the liquid pressure increase of the liquid withdrawn from the evaporation chamber of the second top condenser can in particular take place to a pressure level of 5 to 80 bar. As mentioned, this enables particularly good adaptation to the material flows that are otherwise passed through the main heat exchanger. If the liquid pressure increase of the liquid withdrawn from the evaporation chamber of the second top condenser is at a pressure level well above 8 to 10 bar, it can make sense for cost reasons to heat the liquid to be evaporated in a separate exchanger against process air.
  • air is compressed to at least the first pressure level, a first portion of this air being cooled in the form of one or more compressed air streams in a main heat exchanger of the air separation plant and fed into the high pressure column .
  • This first portion is passed through the main heat exchanger in particular to the cold end and cooled to a temperature level of -150 to -180 ° C.
  • a second portion of this air is cooled in the main heat exchanger, advantageously only to an intermediate temperature level of -50 to -150 ° C., expanded, heated in the main heat exchanger and discharged from the air separation plant. In this way, a loss of cold in the system can be compensated.
  • the present invention also extends to an air separation plant which is set up to carry out a corresponding method and which has the means specified in the associated independent patent claim.
  • this independent patent claim and the above explanations relating to the method proposed according to the invention, which relate to a corresponding air separation plant in the same way.
  • Air separation plants each designated 100, 200 and 300 according to particularly preferred embodiments of the present invention are illustrated in a greatly simplified, schematic representation as process flow diagrams.
  • a so-called warm part of the corresponding air separation plants 100, 200 and 300 is in each case not illustrated in detail, but is indicated in summary with 1.
  • the warm part of an air separation plant includes in particular the so-called main air compressor and a pre-cooling device, for example in the form of a direct contact cooler, connected downstream of this.
  • the warm part of a corresponding air separation plant typically comprises a cleaning device for the air to be processed in the air separation plant, which is typically set up as an adsorber station with suitable molecular sieve adsorbers. These can, in particular, be operated alternately and operated using a regeneration gas, as will also be explained below.
  • a corresponding Adsorber station which is explicitly provided in the warm part 1 of the air separation plants 100, 200 and 300, is designated by 2.
  • a compressed and correspondingly purified feed air stream a which comprises air which is processed in a rectification column system 10.
  • the rectification column system 10 comprises a high pressure column 11 and a low pressure column 12.
  • An essential aspect of the embodiment illustrated here is that the high pressure column 11 and the low pressure column 12 each have top condensers 111 and 121, respectively.
  • a condensate is formed in the top condenser 111, referred to here as the “first” top condenser, which is also referred to here as the “first” condensate. This first condensate is at least partially returned to the high pressure column 11.
  • top condenser 121 referred to here as the "second” top condenser
  • a condensate is formed, which is referred to here as the "second” condensate, and which is partially or completely returned to the low-pressure column 12. Further details are explained below.
  • FIG. 1 to 3 illustrated air separation plants 100, 200 and 300 Another common aspect of the Figures 1 to 3 illustrated air separation plants 100, 200 and 300 is that three partial flows b, c and d of the feed air flow a are formed and are each subjected to a cooling in a main heat exchanger 3.
  • the substreams b are guided through the main heat exchanger 3 up to the cold end and ultimately fed into the high pressure column 11.
  • the partial flow c is only partially cooled in the main heat exchanger 3, expanded in a braked turbine 4, heated again in the main heat exchanger 3, and released into atmosphere A.
  • the formation and expansion of partial flow c is optional.
  • Illustrated air separation plants 100, 200 and 300 designed according to embodiments of the present invention are further characterized in that the first pressure level at which the high-pressure column 11 is operated is significantly above the pressure level at which the high-pressure columns of the in conventional air separation plants used double column systems are operated. Details on the corresponding pressures have already been explained.
  • each pressure nitrogen is provided, which is drawn off from the top of the high pressure column 11 in the form of a stream e, heated in the main heat exchanger 3 and discharged from the air separation plants 100, 200 and 300.
  • a partial flow of the material flow e which is not specifically identified here, can be branched off on the warm side of the main heat exchanger 3 and used, for example, as a sealing gas.
  • a further stream f is also withdrawn from the top of the high-pressure column 11, passed through the already mentioned first condenser-evaporator 111 and at least partially liquefied there.
  • a portion of the correspondingly formed liquid is returned to the high pressure column 11 in the form of a stream g; a further portion can be led to the system boundary in the form of a stream h as a liquid nitrogen product.
  • An oxygen-enriched stream i is discharged from the bottom of the high-pressure column 11, passed through a subcooler 14, and then released into the low-pressure column 12.
  • Top gas of the low-pressure column 12 is taken from this in the form of a stream k and passed through the condenser-evaporator 121. Again, a portion of this can be returned to the low-pressure column 12 in the form of a stream I. Another portion is passed in the form of a stream m by means of a pump 15 through a subcooler 16 and then fed into the high pressure column 12.
  • a stream n is withdrawn from the bottom of the low-pressure column 12 and is likewise passed through the subcooler 16 and then through a subcooler 17 and then expanded into an evaporation space of the top condenser 121.
  • Gas from the evaporation space of the condenser evaporator 121 is withdrawn in the form of a material flow p and optionally, if present, passed through the subcooler 13 and the subcooler 17.
  • the stream p is then heated in the main heat exchanger 3 and can, for example, be used as a regeneration gas in the Adsorber station 2 are used, which is provided in the warm part 1 of the air separation units 100, 200 and 300.
  • liquid is withdrawn in the form of a substance flow q, subjected to a pressure increase by means of a pump 19 in the liquid state, evaporated in the main heat exchanger 3 or transferred to the supercritical state, and used to provide an oxygen-rich, gaseous air product that another main product of the air separation plants 100, 200, 300 according to FIGS Figures 1 to 3 represents.
  • the vaporized or converted into the supercritical state stream q is fed to a consumer 101 in a materially unchanged composition.
  • the illustrated air separation plant 300 represents a variant of the air separation plant 200 according to FIG Figure 2
  • a further oxygen enrichment is carried out, namely in a membrane separation 301.
  • a material flow t which is further enriched in oxygen and a waste flow u can be formed.

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  • Health & Medical Sciences (AREA)
  • Emergency Medicine (AREA)
  • Separation By Low-Temperature Treatments (AREA)
EP19020402.4A 2019-06-25 2019-06-25 Procédé et installation d'obtention d'un produit dérivé de l'air riche en azote et riche en oxygène au moyen d'un fractionnement à basse température de l'air Withdrawn EP3757493A1 (fr)

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EP19020402.4A EP3757493A1 (fr) 2019-06-25 2019-06-25 Procédé et installation d'obtention d'un produit dérivé de l'air riche en azote et riche en oxygène au moyen d'un fractionnement à basse température de l'air

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EP19020402.4A EP3757493A1 (fr) 2019-06-25 2019-06-25 Procédé et installation d'obtention d'un produit dérivé de l'air riche en azote et riche en oxygène au moyen d'un fractionnement à basse température de l'air

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4453957A (en) 1982-12-02 1984-06-12 Union Carbide Corporation Double column multiple condenser-reboiler high pressure nitrogen process
EP0884543A1 (fr) * 1997-06-13 1998-12-16 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Procédé et installation de séparation d'air par distillation cryogénique
EP1055893A1 (fr) * 1999-05-25 2000-11-29 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Système de distillation cryogénique pour la séparation des gaz de l'air
US20070209389A1 (en) 2006-03-10 2007-09-13 Prosser Neil M Cryogenic air separation system for enhanced liquid production
WO2015127648A1 (fr) 2014-02-28 2015-09-03 Praxair Technology, Inc. Distribution de courant de produit sous pression
EP3290843A2 (fr) 2016-07-12 2018-03-07 Linde Aktiengesellschaft Procédé et dispositif destiné à fabriquer de l'azote pressurisé et liquide par décomposition à basse température de l'air

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4453957A (en) 1982-12-02 1984-06-12 Union Carbide Corporation Double column multiple condenser-reboiler high pressure nitrogen process
EP0884543A1 (fr) * 1997-06-13 1998-12-16 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Procédé et installation de séparation d'air par distillation cryogénique
EP1055893A1 (fr) * 1999-05-25 2000-11-29 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Système de distillation cryogénique pour la séparation des gaz de l'air
US20070209389A1 (en) 2006-03-10 2007-09-13 Prosser Neil M Cryogenic air separation system for enhanced liquid production
WO2015127648A1 (fr) 2014-02-28 2015-09-03 Praxair Technology, Inc. Distribution de courant de produit sous pression
EP3290843A2 (fr) 2016-07-12 2018-03-07 Linde Aktiengesellschaft Procédé et dispositif destiné à fabriquer de l'azote pressurisé et liquide par décomposition à basse température de l'air

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
"Industrial Gases Processing", 2006, WILEY-VCH, article "Cryogenic Rectification"
"MIXED PURITY OXYGEN FACILITY", RESEARCH DISCLOSURE, KENNETH MASON PUBLICATIONS, HAMPSHIRE, UK, GB, no. 452, 1 November 2001 (2001-11-01), XP001087237, ISSN: 0374-4353 *

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