WO2021078405A1 - Method and system for low-temperature air separation - Google Patents

Method and system for low-temperature air separation Download PDF

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Publication number
WO2021078405A1
WO2021078405A1 PCT/EP2020/025456 EP2020025456W WO2021078405A1 WO 2021078405 A1 WO2021078405 A1 WO 2021078405A1 EP 2020025456 W EP2020025456 W EP 2020025456W WO 2021078405 A1 WO2021078405 A1 WO 2021078405A1
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Prior art keywords
column
pressure column
pressure
evaporation
liquid
Prior art date
Application number
PCT/EP2020/025456
Other languages
German (de)
French (fr)
Inventor
Stefan Lochner
Original Assignee
Linde Gmbh
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Publication date
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Publication of WO2021078405A1 publication Critical patent/WO2021078405A1/en

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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
    • F25J3/04048—Providing pressurised feed air or process streams within or from the air fractionation unit by compression of cold gaseous streams, e.g. intermediate or oxygen enriched (waste) 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
    • 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
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    • 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
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    • 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
    • F25J3/04096—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 argon or argon enriched stream
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    • F25J3/04151—Purification and (pre-)cooling of the feed air; recuperative heat-exchange with product streams
    • F25J3/04187—Cooling of the purified feed air by recuperative heat-exchange; Heat-exchange with product streams
    • F25J3/04193—Division of the main heat exchange line in consecutive sections having different functions
    • F25J3/04206—Division of the main heat exchange line in consecutive sections having different functions including a so-called "auxiliary vaporiser" for vaporising and producing a gaseous product
    • F25J3/04212—Division of the main heat exchange line in consecutive sections having different functions including a so-called "auxiliary vaporiser" for vaporising and producing a gaseous product and simultaneously condensing vapor from a column serving as reflux within the or another column
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    • 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
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    • 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
    • F25J3/04236—Integration of different exchangers in a single core, so-called integrated cores
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
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    • 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
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    • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
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    • 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
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    • 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
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    • 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
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    • 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
    • F25J3/04333—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using quasi-closed loop internal vapor compression refrigeration cycles, e.g. of intermediate or oxygen enriched (waste-)streams
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    • 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
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    • F25J3/04472—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 the cold from cryogenic liquids produced within the air fractionation unit and stored in internal or intermediate storages
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    • 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
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    • F25J3/04648—Recovering noble gases from air argon
    • F25J3/04654—Producing crude argon in a crude argon column
    • F25J3/04709—Producing crude argon in a crude argon column as an auxiliary column system in at least a dual pressure main column system
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    • F25J2200/90—Details relating to column internals, e.g. structured packing, gas or liquid distribution
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    • F25J2210/06—Splitting of the feed stream, e.g. for treating or cooling in different ways
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2210/00—Processes characterised by the type or other details of the feed stream
    • F25J2210/42—Nitrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2215/00—Processes characterised by the type or other details of the product stream
    • F25J2215/50—Oxygen or special cases, e.g. isotope-mixtures or low purity O2
    • F25J2215/56—Ultra high purity oxygen, i.e. generally more than 99,9% 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
    • F25J2235/58—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams the fluid being argon or crude argon
    • 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
    • F25J2250/00—Details related to the use of reboiler-condensers
    • F25J2250/02—Bath type boiler-condenser using thermo-siphon effect, e.g. with natural or forced circulation or pool boiling, i.e. core-in-kettle heat exchanger
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2250/00—Details related to the use of reboiler-condensers
    • F25J2250/20—Boiler-condenser with multiple exchanger cores in parallel or with multiple re-boiling or condensing 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
    • F25J2270/00—Refrigeration techniques used
    • F25J2270/02—Internal refrigeration with liquid vaporising loop

Definitions

  • the invention relates to a method for the low-temperature decomposition of air and a corresponding system according to the preambles of the independent claims.
  • Air separation plants have rectification column systems which can conventionally be designed, for example, 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” as well as “column” and “column” or terms composed of these are often used synonymously.
  • the rectification columns of the rectification column systems mentioned are operated at different pressure levels.
  • Known double column systems have what is known as a 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 about 5.3 bar.
  • the low-pressure column is operated at a pressure level of typically 1 to 2 bar, in particular about 1.4 bar. In certain cases, higher pressure levels can also be used in both rectification columns.
  • the pressures specified below are absolute pressures at the top of the columns specified in each case.
  • high pressure column, intermediate pressure column and low pressure column are used for certain columns of an air separation plant as described herein.
  • these terms are not intended to restrict the functions of the respective correspondingly designated columns in accordance with a possibly narrow definition that is used in the specialist literature for the columns of a conventional air separation plant.
  • the meaning of the terms results from the following explanations.
  • the present invention comprises the low-temperature decomposition of air according to the so-called SPECTRA method, as is described, inter alia, in EP 2 789 958 A1 and the other patent literature cited therein.
  • SPECTRA processes enable a high nitrogen yield and were originally developed for the production of gaseous pressurized nitrogen.
  • a return to the (in the simplest case only) column is provided here by condensing top gas from this column, as is still customary in this respect.
  • fluid from the same column is used for cooling in the SPECTRA process.
  • additional columns can be provided to obtain additional air components such as pure or high-purity oxygen and argon.
  • additional columns which, however, usually have in common that overhead gas from one of the columns, as in a classic SPECTRA process, using fluid from the same column, which is evaporated and returned to the column Formation of a liquid reflux is condensed on the column.
  • the column operated in this way can, as is the case according to the invention, be the column with the highest operating pressure in the plant.
  • CN 108036584 A discloses a method for the production of high-purity nitrogen and oxygen as well as liquid oxygen by the low-temperature decomposition of air and a corresponding plant. Various factors are fully taken into account in order to achieve stable, efficient and energy-saving operation of the system.
  • the object of the present invention is to improve the SPECTRA methods mentioned and explained in greater detail below, in particular with regard to energy consumption.
  • the present invention proposes a method for the low-temperature decomposition of air and a corresponding system with the features of the respective independent claims. Refinements are the subject matter of the dependent claims and the following description.
  • Liquids and gases can be rich or poor in one or more components as 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 a starting liquid or a starting gas from which the Liquid or gas was obtained.
  • the liquid or gas is "enriched” in the sense understood here, if this or this is at least 1, 1-fold, 1, 5-fold, 2-fold, 5-fold, 10-fold 100-fold or 1,000-fold times the content, and "depleted” if this or this is 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 contains the source 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 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% or 10% around a mean value.
  • Corresponding pressure levels and temperature levels can be in disjoint areas or in areas that overlap one another.
  • pressure levels include, for example, unavoidable or expected pressure losses.
  • the pressure levels specified here in bar are absolute pressures.
  • expansion machines are typically understood to mean known turboexpander. These expansion machines can in particular also be coupled to compressors. 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". In a turbine booster, the turbo expander and the turbo compressor are mechanically coupled, with 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). In general, the term “compressor" is used here.
  • a “cold compressor” here denotes a compressor to which a fluid flow is fed at a temperature level well below 0 ° C, in particular below -50, -75 or -100 ° C and down to -150 or -200 ° C. A the corresponding fluid flow is cooled to a corresponding temperature level in particular by means of the main heat exchanger (see below).
  • the “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 major part of the air supplied to the air separation plant and broken down there is cooled. This takes place at least partially in countercurrent to the material flows that are discharged from the air separation plant. Substance flows or "products" "diverted” from an air separation plant in this way are, in the language used here, fluids which no longer participate in plant-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 is used for the indirect transfer of heat between at least two fluid flows, for example, which flow countercurrently 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 is in indirect heat exchange with a second, evaporating fluid flow occurs.
  • Each condenser-evaporator has a liquefaction space and an evaporation space.
  • the liquefaction and evaporation space have liquefaction and evaporation passages.
  • the condensation (liquefaction) of the first fluid flow is carried out in the liquefaction space, and the evaporation of the second fluid flow in the vaporization space.
  • the evaporation and liquefaction spaces are formed by groups of passages which are in a heat exchange relationship with one another.
  • the axes of the two apparatus parts do not have to be exactly perpendicular, but can also be offset from one another, especially if one of the two apparatus parts, for example a 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 high pressure column, the low pressure column and the intermediate pressure column in the context of the present invention essentially serve to obtain oxygen and nitrogen-rich air products (top gas of the high pressure column is provided under a corresponding pressure as nitrogen pressure product and bottom liquid can be taken from the low pressure column as pure oxygen product), the Another column used in the present invention for the production of argon and is therefore referred to as an argon column.
  • an argon column Like an argon column in a classic air separation plant, this is fed with a side stream from the low-pressure column.
  • side stream is intended to denote a fluid stream that is taken neither from the sump area nor from the head area, i.e. areas below the lowest or above the uppermost separating device (for example a separating tray or a packing area), but between, ie between two corresponding ones Separation devices.
  • Air separation plants with double column systems and so-called crude and possibly so-called pure argon columns are typically used to extract argon.
  • An example is illustrated by Häring (see above) in Figure 2.3A and described from page 26 in the section "Rectification in the Low-pressure, Crude and Pure Argon Column” and from page 29 in the section "Cryogenic Production of Pure Argon".
  • a pure argon column can also be dispensed with in corresponding plants if the rectification columns in question are designed accordingly. Pure argon can then be withdrawn from the crude argon column or a comparable column typically somewhat further below than the fluid conventionally transferred into the pure argon column, with a separation area located above for separation remaining foreign components is used.
  • the argon column used in the context of the present invention can be operated essentially like a conventional crude argon column known from the prior art (or a correspondingly modified crude argon column). Corresponding argon columns can in particular be formed with a corresponding number of plates.
  • the present invention proposes a method for the low-temperature separation of air, in which an air separation plant is used which has a column system comprising a high pressure column, an intermediate pressure column, a low pressure column and an argon column.
  • the high pressure column used in the context of the present invention is that column which is basically operated like the column used in a conventional SPECTRA process.
  • the high, intermediate and low pressure columns which are used in the context of the present invention are also distinguished by their respective operating pressure levels. Specific values are explained below.
  • the high pressure column is operated at a pressure level which is significantly above the pressure level of a conventional high pressure column.
  • a nitrogen product can be removed from the high pressure column, which nitrogen product can be provided directly at a corresponding pressure level and does not require any subsequent compression in the cold or in the warm.
  • the provision of a corresponding pressurized nitrogen product is therefore significantly simpler in terms of apparatus and, if necessary, in terms of safety technology than in a classic air separation plant.
  • the present invention thus benefits from the advantages of a known SPECTRA method.
  • the present invention also enables the production of an oxygen-rich air product and an argon-rich air product, for which the mentioned further columns are used.
  • the high pressure column in the context of the present invention is operated at a first pressure level
  • the low pressure column at a third pressure level below the first and the second pressure level can also be combined in the manner of a conventional double column of an air separation plant.
  • a heat exchanger used to condense top gas from the intermediate pressure column can also be arranged in the bottom of the low pressure column.
  • the double column system used there consists of a high pressure column and a low pressure column, the high pressure column being arranged below the low pressure column in the sense explained above.
  • This can also be the case for the intermediate pressure column (arrangement below the low pressure column) and the low pressure column (arrangement above the intermediate pressure column) in the context of the present invention.
  • the present invention is limited to such an arrangement in the manner of a double column or double column. Rather, the two columns (intermediate pressure column and low pressure column) can also be designed in the form of two separate columns.
  • the condenser connecting the intermediate pressure column and the low pressure column in a heat-exchanging manner can also be arranged outside the low pressure column.
  • the intermediate pressure column is typically operated at a pressure level which corresponds to a conventional high pressure column of an air separation plant.
  • the operating pressure level of the low pressure column also corresponds to the usual operating pressure level of a classic low pressure column.
  • a condensate is formed from overhead gas of the high pressure column with evaporation or partial evaporation of a first liquid which is taken from the high pressure column and expanded to an evaporation pressure level between the first and the second pressure level .
  • the evaporation pressure level can typically be 3 to 7 bar.
  • the Relaxation thus takes place in the form of partial relaxation to a superatmospheric pressure level, which allows further relaxation to a lower pressure level.
  • the condensate formed is partially or completely fed back into the high pressure column as reflux. Part of a corresponding condensate can also be discharged from a corresponding system as a liquid, nitrogen-rich air product.
  • a first gas is formed which is partially or completely recompressed to the first pressure level and fed back into the high-pressure column. This is an essential feature of a SPECTRA process.
  • the first liquid withdrawn from the high pressure column which is treated accordingly in the context of the present invention, can in particular be a liquid which is withdrawn from the high pressure column a few theoretical or practical trays above the bottom, which In other words, it is carried out in the form of a side stream from the high pressure column.
  • the top condensate is formed from the top gas of the high pressure column with evaporation or partial evaporation of a second liquid which is taken from the intermediate pressure column and compressed to the evaporation pressure level between the first and the second pressure level.
  • a second gas is formed, which is partially or completely expanded to the second pressure level and fed back into the intermediate pressure column.
  • the present invention thus creates two material cycles, namely the material cycle to which the first liquid from the high pressure column is subjected and a second material cycle to which a liquid from the intermediate pressure column is subjected. While the first cycle still corresponds to a typical SPECTRA process, the second cycle, as used according to the invention, is new compared to the prior art.
  • a pump is typically provided which pressurizes the second liquid in the liquid state. While the first liquid from the high pressure column is typically a side stream from the high pressure column, the second liquid from the intermediate pressure column, on the other hand, is formed using bottom liquid.
  • the high pressure column is fed in particular with compressed and cooled feed air. This does not rule out that other columns are also fed with air accordingly; However, this is always provided in the case of the high pressure column used according to the invention.
  • bottom liquid from the high pressure column is expanded from the first to the second pressure level and fed into the intermediate pressure column. This is also typically not the case in conventional SPECTRA processes, even if further columns are used there; a corresponding stream of material, which is formed using bottom liquid, is also used in conventional processes of this kind as a coolant for the condensation of top gas of the corresponding column.
  • a side stream withdrawn from the high-pressure column in the liquid state is also partially or completely expanded from the first to the second pressure level and with the formation of a liquid component and a gas component fed to a phase separation.
  • the liquid fraction can in particular be partially or completely subjected to a separation in the low-pressure column and the gas fraction can be partially or completely subjected to a separation in the intermediate-pressure column.
  • a particular embodiment of such a process comprises feeding the side stream withdrawn from the high pressure column or its component, which has been expanded from the first to the second pressure level, for the phase separation into the intermediate pressure column, where the liquid component is deposited in liquid form, for example in a liquid retention container or on a separation tray, and the gas portion goes directly into the gas phase.
  • the liquid fraction can be partially or completely withdrawn from the intermediate pressure column and fed into the low pressure column, where it is subjected to the separation that takes place there.
  • the gas fraction is left in the intermediate pressure column and is subjected to separation there.
  • the argon column used is operated essentially in the manner of a conventional argon column of an air separation plant.
  • an argon-enriched side stream is withdrawn from the low-pressure column, at least part of the second stream being fed from the low-pressure column into the argon column.
  • the side stream enriched in argon has, in particular, a higher argon content than is present at the top or bottom of the low-pressure column. It is taken from the low-pressure column in an advantageous area known in principle from the area of air separation plants.
  • the argon column is operated using a top condenser.
  • a condensate is formed from the top gas of the argon column with partial evaporation of liquid, which is partially or completely fed back into the argon column.
  • the liquid, with the partial evaporation of which the condensate is formed from the top gas of the argon column, is advantageously removed from the intermediate pressure column within the scope of the present invention, which represents a further fundamental difference compared to known processes.
  • a gas formed in the partial evaporation and / or liquid remaining in the partial evaporation can be fed partially or completely into the low-pressure column.
  • expanders coupled with compressors can be used.
  • a compressor can be used that is mechanically coupled to an expansion machine that is used to depressurize a further portion of the second gas, the is not fed back into the intermediate pressure column is used.
  • the present invention also extends to an air separation plant, for the specific features of which reference is made to the corresponding independent patent claim.
  • an air separation plant is advantageously set up to carry out a method as has been explained above in different configurations.
  • FIG. 1 illustrates an air separation plant according to an embodiment of the present invention in the form of a simplified process flow diagram.
  • FIG. 1 an air separation plant according to a particularly preferred embodiment of the present invention is shown in the form of a greatly simplified, schematic process flow diagram and denoted as a whole by 100.
  • the air separation plant 100 illustrated in FIG. 1 is sucked in air from the atmosphere, here denoted generally by A, via a filter 101 by means of a main air compressor 102, which is in particular multi-stage and with intermediate cooling. After after-cooling in heat exchangers 103 and 104, a feed air stream a formed in this way is cooled in a direct contact cooler 105 operated with water W and then fed to an adsorption device 106.
  • the feed air stream a After the feed air stream a has been dried in this way and essentially freed from carbon dioxide, it is fed to a main heat exchanger 107.
  • the feed air stream a is taken from the main heat exchanger near its cold end and, in the example illustrated here, is essentially fed to the high pressure column 11 of a column system designated overall by 10. A part that is not shown separately can be branched off via a bypass if required.
  • a top stream b of the high pressure column 11 can be discharged from the air separation plant 100 in part in the form of a stream c as a gaseous pressurized nitrogen product.
  • Corresponding pressurized nitrogen products are again labeled C1 and C2.
  • a portion of the top stream b that is not diverted from the air separation plant is fed to a heat exchanger or condenser 108 in the form of a material stream d and is essentially condensed there.
  • a portion of the corresponding condensate can be returned to the high pressure column 11 as a liquid reflux in the form of a stream e. Another portion is withdrawn in the form of a flushing flow P.
  • liquid nitrogen E can also be fed into the system 100 in the manner illustrated here.
  • Another portion can be subcooled in the form of a material flow f in a subcooler 109 and as a liquid nitrogen product F from the system be diverted.
  • a portion that is used for subcooling and is branched off downstream of subcooler 109 is discharged from the system as residual gas, as also explained below with reference to further material flows.
  • an intermediate pressure column 12 of the column system 10 is fed by means of a bottom stream g of the high pressure column 11.
  • this bottom stream g is cooled in the main heat exchanger 107 and then fed into the intermediate pressure column above the bottom or above some separating trays which are above the bottom.
  • the intermediate pressure column is further fed by means of a side stream h from the high pressure column 11, which is depressurized into the intermediate pressure column 12. Gas formed in this way is left in the intermediate pressure column 12; on the other hand, liquid in the form of a stream i is at least partially withdrawn from the intermediate pressure column 12 directly below the feed point and first passed through a subcooler 110 and then fed into a low pressure column 13 of the column system 10.
  • the heat exchanger 108 is initially operated using a side stream k withdrawn from the high pressure column. This is first cooled further in the main heat exchanger 107 and then fed to the heat exchanger 108. Partial relaxation takes place. Downstream of the heat exchanger 108, part of the correspondingly evaporated fluid can be released into atmosphere A. Another part is recompressed, as further illustrated here in the form of a material flow k, possibly after combining with other material flows, in a compressor 111, which is mechanically coupled to an expansion machine 112 and additionally braked by means of a dissipative brake. The stream k can be fed into the high pressure column 11 again in this way. Further cooling capacity for the heat exchanger 108 is provided by a bottom stream I of the intermediate pressure column 12. For this purpose, this is brought to a pressure level required in the heat exchanger 108 by means of a pump 113.
  • the material flow I is heated in the form of a first partial flow m in the main heat exchanger 107 and at least partially expanded in the expansion machine 112. This material flow is then, in particular together with the portion of the overhead stream b used for cooling in the subcooler 109, discharged from the high pressure column from the plant. A further portion n of the bottom stream from the intermediate pressure column 12 evaporated in the heat exchanger 108, on the other hand, is returned to the intermediate pressure column 12.
  • the air separation plant 100 further comprises an argon column 14, which is ultimately fed from the low-pressure column 13 or by means of a side stream o withdrawn from the low-pressure column 13.
  • the side stream o is not transferred directly to the argon column 14, but instead is first transferred to an upper part 15a of an oxygen column designated as a whole by 15.
  • the stream o or the fluid transferred in this way to the upper part 15a is further enriched in argon and depleted in oxygen, so that a corresponding stream p can be transferred from the top of the upper part 15a to the argon column 14 .
  • Bottom liquid from the argon column 14 is returned to the upper part 15a of the oxygen column via a pump, which is not specifically designated here.
  • the oxygen column 15 with the upper part 15a and the lower part 15b is operated with a bottom evaporator 151.
  • This bottom evaporator 151, and a bottom evaporator 131 arranged in the bottom of the low-pressure column 13, are each used to condense top gas from the intermediate pressure column 12, which gas is withdrawn from it in the form of a stream q.
  • a condensed portion is, as not illustrated separately and individually here, essentially used as reflux to the intermediate pressure column 12 and to the low pressure column 13.
  • a stream r is withdrawn from the top of the low-pressure column 13 and blown off in the form of impure oxygen after heating to the atmosphere or used in another way.
  • Oxygen streams s and t are withdrawn from the bottom of the low-pressure column 13, with the oxygen stream s being internally compressed in a pump, which is not specifically designated, and can be used to provide a corresponding internal compression product S.
  • the oxygen flow t can be heated and discharged from the system or released into the atmosphere become.
  • a part can, as illustrated here in the form of a link X, be returned to the low-pressure column 13.
  • the argon column 14 the top of which is cooled by means of a top condenser 141, can be used to provide a liquid argon stream u, which can be provided as an internally compressed argon product U, for example after being temporarily stored in a tank system T. A part of this can also be stored permanently in a storage tank T1 and, for example, can be run out of the system in liquid form.
  • the top condenser 141 of the argon column 14 is cooled using a stream v which is withdrawn in liquid form from the intermediate pressure column 12 a few floors above the sump and fed into an evaporation chamber of the argon condenser 141. Fractions that have evaporated or that have not been evaporated here can be returned to the low-pressure column in the manner illustrated.
  • the upper part 15a and the lower part 15b of the oxygen column 15 are fluidically coupled to one another, as illustrated here in the form of corresponding fluid arrows. Fluid depleted in argon and enriched in oxygen is transferred from the upper part 15a to the lower part 15b, where it is further rectified. In this way, a pure oxygen stream w can be taken from the bottom of the oxygen column 15 or its lower part, which can also be carried out from the air separation plant 100 as a pure oxygen product W in internally compressed form via a corresponding tank system t2 or t3. Further material flows illustrated here and their specific treatment in the air separation plant 100 result directly from the drawing.

Abstract

The invention relates to a method for low-temperature air separation, wherein an air separation system (100) is used which has a column system (10) comprising a high pressure column (11), which is supplied with condensed and cooled air, an intermediate pressure column (12), a low pressure column (13) and an argon column (14). A condensate is formed from head gas of the high pressure column (11), with the evaporation or partial evaporation of a first liquid which is taken from the high pressure column (11) and expanded to an evaporation pressure level between the first and the second pressure levels, and said condensate is fed back in part or in full to the high pressure column (11). Upon evaporation of the first liquid, a first gas is formed which is re-condensed in part or in full to the first pressure level and fed back into the high pressure column (11). The condensate is furthermore formed from the head gas of the high pressure column (11) according to the present invention with evaporation or partial evaporation of a second liquid which is taken from the intermediate pressure column (12) and condensed to the evaporation pressure level between the first and the second pressure levels, wherein a second gas is formed upon evaporation of the second liquid, which second gas is expanded in part or in full to the second pressure level and fed back into the intermediate pressure column (11). The invention also relates to a corresponding air separation system (100).

Description

Beschreibung description
Verfahren und Anlaoe zur Tieftemperaturzerleauna von Luft Procedure and reason for the low-temperature decomposition of air
Die Erfindung betrifft ein Verfahren zur Tieftemperaturzerlegung von Luft und eine entsprechende Anlage gemäß den Oberbegriffen der unabhängigen Patentansprüche. The invention relates to a method for the low-temperature decomposition of air and a corresponding system according to the preambles of the independent claims.
Stand der Technik State of the art
Die Herstellung von Luftprodukten in flüssigem oder gasförmigem Zustand durch Tieftemperaturzerlegung von Luft in Luftzerlegungsanlagen ist bekannt und beispielsweise bei H.-W. Häring (Hrsg.), Industrial Gases Processing, Wiley-VCH,The production of air products in the liquid or gaseous state by the low-temperature decomposition of air in air separation plants is known and, for example, from H.-W. Häring (Ed.), Industrial Gases Processing, Wiley-VCH,
2006, insbesondere Abschnitt 2.2.5, "Cryogenic Rectification", beschrieben. 2006, especially Section 2.2.5, "Cryogenic Rectification".
Luftzerlegungsanlagen weisen Rektifikationskolonnensysteme auf, die herkömmlicherweise beispielsweise als Zweikolonnensysteme, insbesondere als klassische Linde-Doppelkolonnensysteme, aber auch als Drei- oder Mehrkolonnensysteme ausgebildet sein können. Neben den Rektifikationskolonnen zur Gewinnung von Stickstoff und/oder Sauerstoff in flüssigem und/oder gasförmigem Zustand, also den Rektifikationskolonnen zur Stickstoff-Sauerstoff-Trennung, können Rektifikationskolonnen zur Gewinnung weiterer Luftkomponenten, insbesondere der Edelgase Krypton, Xenon und/oder Argon, vorgesehen sein. Häufig werden dabei die Begriffe "Rektifikation" und "Destillation" sowie "Säule" und "Kolonne" bzw. hieraus zusammengesetzte Begriffe synonym verwendet. Air separation plants have rectification column systems which can conventionally be designed, for example, as two-column systems, in particular as classic Linde double-column systems, but also as three- or multi-column systems. In addition to the 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” as well as “column” and “column” or terms composed of these are often used synonymously.
Die Rektifikationskolonnen der genannten Rektifikationskolonnensysteme werden auf unterschiedlichen Druckniveaus betrieben. Bekannte Doppelkolonnensysteme weisen eine sogenannte Hochdruckkolonne (auch als Druckkolonne, Mitteldruckkolonne oder untere Kolonne bezeichnet) und eine sogenannte Niederdruckkolonne (auch als obere Kolonne bezeichnet) auf. Die Hochdruckkolonne wird typischerweise auf einem Druckniveau von 4 bis 7 bar, insbesondere ca. 5,3 bar, betrieben. Die Niederdruckkolonne wird auf einem Druckniveau von typischerweise 1 bis 2 bar, insbesondere ca. 1 ,4 bar, betrieben. In bestimmten Fällen können in beiden Rektifikationskolonnen auch höhere Druckniveaus eingesetzt werden. Bei den hier und nachfolgend angegebenen Drücken handelt es sich um Absolutdrücke am Kopf der jeweils angegebenen Kolonnen. The rectification columns of the rectification column systems mentioned are operated at different pressure levels. Known double column systems have what is known as a 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 about 5.3 bar. The low-pressure column is operated at a pressure level of typically 1 to 2 bar, in particular about 1.4 bar. In certain cases, higher pressure levels can also be used in both rectification columns. With the here and The pressures specified below are absolute pressures at the top of the columns specified in each case.
Nachfolgend werden für bestimmte Kolonnen einer Luftzerlegungsanlage, wie sie hierin beschrieben wird, die Begriffe Hochdruckkolonne, Zwischendruckkolonne und Niederdruckkolonne verwendet. Diese Begriffe sollen die Funktionen der jeweils entsprechend bezeichneten Kolonnen jedoch nicht entsprechend einer möglicherweise engen Definition, die in der Fachliteratur für die Kolonnen einer herkömmlichen Luftzerlegungsanlage verwendet wird, einschränken. Die Bedeutung der Begriffe ergibt sich aus den nachfolgenden Erläuterungen. In the following, the terms high pressure column, intermediate pressure column and low pressure column are used for certain columns of an air separation plant as described herein. However, these terms are not intended to restrict the functions of the respective correspondingly designated columns in accordance with a possibly narrow definition that is used in the specialist literature for the columns of a conventional air separation plant. The meaning of the terms results from the following explanations.
Die vorliegende Erfindung umfasst die Tieftemperaturzerlegung von Luft gemäß dem sogenannten SPECTRA-Verfahren, wie es unter anderem in der EP 2 789 958 A1 und der weiteren dort zitierten Patentliteratur beschrieben ist. Es handelt sich hierbei in der einfachsten Ausgestaltung um ein Einkolonnenverfahren. SPECTRA-Verfahren ermöglichen eine hohe Sickstoffausbeute und wurden ursprünglich zur Gewinnung von gasförmigem Druckstickstoff entwickelt. Ein Rücklauf auf die (im einfachsten Fall einzige) Kolonne wird hier durch Kondensieren von Kopfgas dieser Kolonne bereitgestellt, wie insoweit noch üblich. In dem zum Kondensieren von Kopfgas verwendeten Wärmetauscher wird in SPECTRA-Verfahren aber Fluid aus derselben Kolonne zur Kühlung eingesetzt. Mittels eines (Kalt-) Verdichters werden Teile des zur Kühlung verwendeten Fluides nach der Verwendung zur Kühlung und der damit einhergehenden Verdampfung in die Rektifikationskolonne zurückgeführt. Hierdurch können sehr günstige Luftfaktoren erreicht werden, also eine große Menge an Produkt pro eingesetzter Menge Luft. The present invention comprises the low-temperature decomposition of air according to the so-called SPECTRA method, as is described, inter alia, in EP 2 789 958 A1 and the other patent literature cited therein. In the simplest embodiment, this is a single-column process. SPECTRA processes enable a high nitrogen yield and were originally developed for the production of gaseous pressurized nitrogen. A return to the (in the simplest case only) column is provided here by condensing top gas from this column, as is still customary in this respect. In the heat exchanger used to condense overhead gas, however, fluid from the same column is used for cooling in the SPECTRA process. By means of a (cold) compressor, parts of the fluid used for cooling are returned to the rectification column after being used for cooling and the associated evaporation. In this way, very favorable air factors can be achieved, i.e. a large amount of product per amount of air used.
In Ausgestaltungen von SPECTRA-Verfahren können zur Gewinnung von weiteren Luftkomponenten wie reinem oder hochreinem Sauerstoff und Argon weitere Kolonnen bereitgestellt sein. Es ergeben sich entsprechend modifizierte SPECTRA-Verfahren mit zusätzlichen Kolonnen, die aber üblicherweise gemeinsam haben, dass Kopfgas einer der Kolonnen, wie in einem klassischen SPECTRA-Verfahren, unter Verwendung von Fluid derselben Kolonne, das dabei verdampft und in die Kolonne zurückgeführt wird, zur Bildung eines flüssigen Rücklaufs auf die Kolonne kondensiert wird. Die auf diese Weise betriebene Kolonne kann, wie erfindungsgemäß der Fall, jene Kolonne mit dem höchsten Betriebsdruck in der Anlage sein. Die CN 108036584 A offenbart ein Verfahren zur Herstellung von hochreinem Stickstoff und Sauerstoff sowie flüssigem Sauerstoff durch Tieftemperaturzerlegung von Luft und eine entsprechende Anlage. Es werden unterschiedliche Faktoren in vollem Umfang berücksichtigt, um einen stabilen, effizienten und energiesparenden Betrieb der Anlage zu erreichen. In embodiments of the SPECTRA process, additional columns can be provided to obtain additional air components such as pure or high-purity oxygen and argon. This results in correspondingly modified SPECTRA processes with additional columns, which, however, usually have in common that overhead gas from one of the columns, as in a classic SPECTRA process, using fluid from the same column, which is evaporated and returned to the column Formation of a liquid reflux is condensed on the column. The column operated in this way can, as is the case according to the invention, be the column with the highest operating pressure in the plant. CN 108036584 A discloses a method for the production of high-purity nitrogen and oxygen as well as liquid oxygen by the low-temperature decomposition of air and a corresponding plant. Various factors are fully taken into account in order to achieve stable, efficient and energy-saving operation of the system.
Die vorliegende Erfindung stellt sich die Aufgabe, die angesprochenen und weiter unten noch ausführlicher erläuterten SPECTRA-Verfahren zu verbessern, insbesondere hinsichtlich des Energieverbrauchs. The object of the present invention is to improve the SPECTRA methods mentioned and explained in greater detail below, in particular with regard to energy consumption.
Offenbarung der Erfindung Disclosure of the invention
Vor diesem Hintergrund schlägt die vorliegende Erfindung ein Verfahren zur Tieftemperaturzerlegung von Luft und eine entsprechende Anlage mit den Merkmalen der jeweiligen unabhängigen Patentansprüche vor. Ausgestaltungen sind jeweils Gegenstand der abhängigen Patentansprüche und der nachfolgenden Beschreibung. Against this background, the present invention proposes a method for the low-temperature decomposition of air and a corresponding system with the features of the respective independent claims. Refinements are the subject matter of the dependent claims and the following description.
Vor der Erläuterung der Merkmale und Vorteile der vorliegenden Erfindung werden einige Grundlagen der vorliegenden Erfindung näher erläutert und nachfolgend verwendete Begriffe definiert. Before explaining the features and advantages of the present invention, some fundamentals of the present invention are explained in more detail and the terms used below are defined.
Die in einer Luftzerlegungsanlage eingesetzten Vorrichtungen sind in der zitierten Fachliteratur, beispielsweise bei Häring (s.o.) in Abschnitt 2.2.5.6, "Apparatus", beschrieben. Sofern die nachfolgenden Definitionen nicht hiervon abweichen, wird daher zum Sprachgebrauch, der im Rahmen der vorliegenden Anmeldung verwendet wird, ausdrücklich auf die zitierte Fachliteratur verwiesen. The devices used in an air separation plant are described in the cited specialist literature, for example in Häring (see above) in Section 2.2.5.6, "Apparatus". Insofar as the following definitions do not deviate therefrom, express reference is therefore made to the technical literature cited for the language used in the context of the present application.
Flüssigkeiten und Gase können im hier verwendeten Sprachgebrauch reich oder arm an einer oder an mehreren Komponenten sein, wobei "reich" für einen Gehalt von wenigstens 75%, 90%, 95%, 99%, 99,5%, 99,9% oder 99,99% und "arm" für einen Gehalt von höchstens 25%, 10%, 5%, 1%, 0,1% oder 0,01% auf Mol-, Gewichts- oder Volumenbasis stehen kann. Der Begriff "überwiegend" kann der Definition von "reich" entsprechen. Flüssigkeiten und Gase können ferner angereichert oder abgereichert an einer oder mehreren Komponenten sein, wobei sich diese Begriffe auf einen Gehalt in einer Ausgangsflüssigkeit oder einem Ausgangsgas beziehen, aus der oder dem die Flüssigkeit oder das Gas gewonnen wurde. Die Flüssigkeit oder das Gas sei dabei im hier verstandenen Sinn "angereichert", wenn diese oder dieses zumindest den 1 ,1- fachen, 1 ,5-fachen, 2-fachen, 5-fachen, 10-fachen 100-fachen oder 1.000-fachen Gehalt, und "abgereichert", wenn diese oder dieses höchstens den 0,9-fachen, 0,5- fachen, 0,1 -fachen, 0,01 -fachen oder 0,001 -fachen Gehalt einer entsprechenden Komponente, bezogen auf die Ausgangsflüssigkeit oder das Ausgangsgas enthält. Ist hier beispielsweise von "Sauerstoff", "Stickstoff" oder "Argon" die Rede, sei hierunter auch eine Flüssigkeit oder ein Gas verstanden, die bzw. das reich an Sauerstoff oder Stickstoff ist, jedoch nicht ausschließlich hieraus bestehen muss. Liquids and gases can be rich or poor in one or more components as 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 a starting liquid or a starting gas from which the Liquid or gas was obtained. The liquid or gas is "enriched" in the sense understood here, if this or this is at least 1, 1-fold, 1, 5-fold, 2-fold, 5-fold, 10-fold 100-fold or 1,000-fold times the content, and "depleted" if this or this is 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 contains the source 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 have to consist exclusively of these.
Die vorliegende Anmeldung verwendet zur Charakterisierung von Drücken und Temperaturen die Begriffe "Druckniveau" und "Temperaturniveau", wodurch zum Ausdruck gebracht werden soll, dass entsprechende Drücke und Temperaturen in einer entsprechenden Anlage nicht in Form exakter Druck- bzw. Temperaturwerte verwendet werden müssen, um das erfinderische Konzept zu verwirklichen. Jedoch bewegen sich derartige Drücke und Temperaturen typischerweise in bestimmten Bereichen, die beispielsweise ± 1%, 5% oder 10% um einen Mittelwert liegen. Entsprechende Druckniveaus und Temperaturniveaus können dabei in disjunkten Bereichen liegen oder in Bereichen, die einander überlappen. Insbesondere schließen beispielsweise Druckniveaus unvermeidliche oder zu erwartende Druckverluste ein. Entsprechendes gilt für Temperaturniveaus. Bei den hier in bar angegebenen Druckniveaus handelt es sich um Absolutdrücke. The present application uses the terms "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. However, such pressures and temperatures typically move in certain ranges, for example ± 1%, 5% or 10% around a mean value. Corresponding pressure levels and temperature levels can be in disjoint areas or in areas that overlap one another. In particular, pressure levels include, for example, unavoidable or expected pressure losses. The same applies to temperature levels. The pressure levels specified here in bar are absolute pressures.
Ist hier von "Entspannungsmaschinen" die Rede, seien darunter typischerweise bekannte Turboexpander verstanden. Diese Entspannungsmaschinen können insbesondere auch mit Verdichtern gekoppelt sein. Bei diesen Verdichtern kann es sich insbesondere um Turboverdichter handeln. Eine entsprechende Kombination aus Turboexpander und Turboverdichter wird typischerweise auch als "Turbinenbooster" bezeichnet. In einem Turbinenbooster sind der Turboexpander und der Turboverdichter mechanisch gekoppelt, wobei die Kopplung drehzahlgleich (beispielsweise über eine gemeinsame Welle) oder drehzahlunterschiedlich (beispielsweise über ein geeignetes übersetzendes Getriebe) erfolgen kann. Allgemein wird hier der Begriff "Verdichter" verwendet. Ein "Kaltverdichter" bezeichnet dabei hier einen Verdichter, dem ein Fluidstrom auf einem Temperaturniveau deutlich unterhalb von 0 °C, insbesondere unterhalb von -50, -75 oder -100 °C und bis zu -150 oder -200 °C zugeführt wird. Ein entsprechender Fluidstrom wird insbesondere mittels des Hauptwärmetauschers (siehe sogleich) auf ein entsprechendes Temperaturniveau abgekühlt. If "expansion machines" are used here, they are typically understood to mean known turboexpander. These expansion machines can in particular also be coupled to compressors. 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". In a turbine booster, the turbo expander and the turbo compressor are mechanically coupled, with 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). In general, the term "compressor" is used here. A “cold compressor” here denotes a compressor to which a fluid flow is fed at a temperature level well below 0 ° C, in particular below -50, -75 or -100 ° C and down to -150 or -200 ° C. A the corresponding fluid flow is cooled to a corresponding temperature level in particular by means of the main heat exchanger (see below).
Der "Hauptluftverdichter" zeichnet sich dadurch aus, dass durch ihn die gesamte, der Luftzerlegungsanlage zugeführte und dort zerlegte Luft verdichtet wird. Hingegen wird in einem oder mehreren optional vorgesehenen weiteren Verdichtern, beispielsweise Nachverdichtern, nur jeweils ein Anteil dieser bereits zuvor im Hauptluftverdichter verdichteten Luft weiter verdichtet. Entsprechend stellt der "Hauptwärmetauscher" einer Luftzerlegungsanlage den Wärmetauscher dar, in dem zumindest der überwiegende Anteil der der Luftzerlegungsanlage zugeführten und dort zerlegten Luft abgekühlt wird. Dies erfolgt zumindest zum Teil im Gegenstrom zu Stoffströme, die aus der Luftzerlegungsanlage ausgeleitet werden. In derartiger Weise aus einer Luftzerlegungsanlage "ausgeleitete" Stoffströme oder "Produkte" sind im hier verwendeten Sprachgebrauch Fluide, die nicht mehr an anlageninternen Kreisläufen teilnehmen, sondern diesen dauerhaft entzogen werden. The "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. Correspondingly, the “main heat exchanger” of an air separation plant represents the heat exchanger in which at least the major part of the air supplied to the air separation plant and broken down there is cooled. This takes place at least partially in countercurrent to the material flows that are discharged from the air separation plant. Substance flows or "products" "diverted" from an air separation plant in this way are, in the language used here, fluids which no longer participate in plant-internal circuits, but are permanently withdrawn from them.
Ein "Wärmetauscher" zum Einsatz im Rahmen der vorliegenden Erfindung kann in fachüblicher Art ausgebildet sein. Er dient zur indirekten Übertragung von Wärme zwischen zumindest zwei z.B. im Gegenstrom zueinander geführten Fluidströmen, beispielsweise einem warmen Druckluftstrom und einem oder mehreren kalten Fluidströmen oder einem tiefkalten flüssigen Luftprodukt und einem oder mehreren warmen bzw. wärmeren, ggf. aber auch noch tiefkalten Fluidströmen. Ein Wärmetauscher kann aus einem einzelnen oder mehreren parallel und/oder seriell verbundenen Wärmetauscherabschnitten gebildet sein, z.B. aus einem oder mehreren Plattenwärmetauscherblöcken. Es handelt sich beispielsweise um einen Plattenwärmetauscher (engl. Plate Fin Heat Exchanger). Ein derartiger Wärmetauscher weist "Passagen" auf, die als voneinander getrennte Fluidkanäle mit Wärmeaustauschflächen ausgebildet und parallel und durch andere Passagen getrennt zu "Passagengruppen" zusammengeschlossen sind. Kennzeichen eines Wärmetauschers ist, dass in ihm zu einem Zeitpunkt Wärme zwischen zwei mobilen Medien ausgetauscht wird, nämlich wenigstens einem abzukühlenden und wenigstens einem zu erwärmenden Fluidstrom. A “heat exchanger” for use in the context of the present invention can be designed in a manner customary in the art. It is used for the indirect transfer of heat between at least two fluid flows, for example, which flow countercurrently 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.
Als "Kondensatorverdampfer" wird ein Wärmetauscher bezeichnet, in dem ein erster, kondensierender Fluidstrom in indirekten Wärmeaustausch mit einem zweiten, verdampfenden Fluidstrom tritt. Jeder Kondensatorverdampfer weist einen Verflüssigungsraum und einen Verdampfungsraum auf. Verflüssigungs- und Verdampfungsraum weisen Verflüssigungs- bzw. Verdampfungspassagen auf. In dem Verflüssigungsraum wird die Kondensation (Verflüssigung) des ersten Fluidstroms durchgeführt, in dem Verdampfungsraum die Verdampfung des zweiten Fluidstroms. Der Verdampfungs- und der Verflüssigungsraum werden durch Gruppen von Passagen gebildet, die untereinander in Wärmeaustauschbeziehung stehen. A "condenser evaporator" is a heat exchanger in which a first, condensing fluid flow is in indirect heat exchange with a second, evaporating fluid flow occurs. Each condenser-evaporator has a liquefaction space and an evaporation space. The liquefaction and evaporation space have liquefaction and evaporation passages. The condensation (liquefaction) of the first fluid flow is carried out in the liquefaction space, and the evaporation of the second fluid flow in the vaporization space. The evaporation and liquefaction spaces are formed by groups of passages which are in a heat exchange relationship with one another.
Die relativen räumlichen Begriffe "oben", "unten", "über", "unter", "oberhalb", "unterhalb", "neben", "nebeneinander", "vertikal", "horizontal" etc. beziehen sich hier auf die räumliche Ausrichtung der Kolonnen einer Luftzerlegungsanlage im Normalbetrieb. Unter einer Anordnung zweier Kolonnen oder anderer Komponenten "übereinander" wird hier verstanden, dass das sich obere Ende des unteren der beiden Apparateteile auf niedrigerer oder gleicher geodätischer Flöhe befindet wie das untere Ende der oberen der beiden Apparateteile und sich die Projektionen der beiden Apparateteile in einer horizontalen Ebene überschneiden. Insbesondere sind die beiden Apparateteile genau übereinander angeordnet, das heißt die Achsen der beiden Apparateteile verlaufen auf derselben vertikalen Geraden. Die Achsen der beiden Apparateteile müssen jedoch nicht genau senkrecht übereinander liegen, sondern können auch gegeneinander versetzt sein, insbesondere wenn einer der beiden Apparateteile, beispielsweise eine Kolonne oder ein Kolonnenteil mit geringerem Durchmesser, denselben Abstand zum Blechmantel einer Coldbox aufweisen soll wie ein anderer mit größerem Durchmesser. 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 columns of an air separation plant in normal operation. An arrangement of two columns or other components "one above the other" is understood here to mean that the upper end of the lower of the two apparatus parts is on a lower or the same geodetic level as the lower end of the upper of the two apparatus parts and the projections of the two apparatus parts are in one overlap horizontal plane. In particular, the two parts of the apparatus are arranged exactly one above the other, that is, the axes of the two parts of the apparatus run on the same vertical straight line. The axes of the two apparatus parts do not have to be exactly perpendicular, but can also be offset from one another, especially if one of the two apparatus parts, for example a 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.
Wie bei anderen Verfahren zur Tieftemperaturzerlegung von Luft auch, wird beim eingangs erwähnten SPECTRA-Verfahren, das nachfolgend näher erläutert wird, verdichtete und vorgereinigte Luft auf eine für die Rektifikation geeignete Temperatur abgekühlt. Sie kann hierdurch teilweise verflüssigt werden. Die Luft wird anschließend in eine Kolonne eingespeist und dort in einem herkömmlichen SPECTRA-Verfahren unter dem typischen Druck einer klassischen Hochdruckkolonne wie eingangs erläutert unter Erhalt eines gegenüber atmosphärischer Luft an Stickstoff angereicherten Kopfprodukts und eines flüssigen, gegenüber atmosphärischer Luft an Sauerstoff angereicherten Sumpfprodukts rektifiziert. Eine entsprechende Rektifikationskolonne, die allerdings auf einem höheren Druck betrieben werden kann, ist auch in dem erfindungsgemäß vorgeschlagenen Verfahren vorhanden und wird hier durch die als Hochdruckkolonne bezeichnete Kolonne gebildet. Teil der im Rahmen der vorliegenden Erfindung eingesetzten Luftzerlegungsanlage sind daneben auch eine als Niederdruckkolonne auf leicht überatmosphärischem Druckniveau betriebene Kolonne und eine Zwischendruckkolonne, die auf einem Druckniveau zwischen der Hoch- und der Niederdruckkolonne betrieben wird, vorgesehen. As with other processes for the low-temperature separation of air, in the SPECTRA process mentioned at the beginning, which is explained in more detail below, compressed and pre-cleaned air is cooled to a temperature suitable for rectification. This can partially liquefy it. The air is then fed into a column and rectified there in a conventional SPECTRA process under the typical pressure of a classic high pressure column, as explained at the beginning, to obtain a top product enriched in nitrogen compared to atmospheric air and a liquid bottom product enriched in oxygen compared to atmospheric air. A corresponding rectification column, which, however, can be operated at a higher pressure, is also present in the process proposed according to the invention and is formed here by the column referred to as the high pressure column. Part of the air separation plant used in the context of the present invention also includes a column operated as a low pressure column at a pressure level slightly above atmospheric and an intermediate pressure column operated at a pressure level between the high and low pressure columns.
Während die Hochdruckkolonne, die Niederdruckkolonne und die Zwischendruckkolonne im Rahmen der vorliegenden Erfindung im Wesentlichen zur Gewinnung von Sauerstoff- und stickstoffreichen Luftprodukten dienen (Kopfgas der Hochdruckkolonne wird unter einem entsprechenden Druck als Stickstoffdruckprodukt bereitgestellt und der Niederdruckkolonne kann Sumpfflüssigkeit als Reinsauerstoffprodukt entnommen werden), dient die weitere, in der vorliegenden Erfindung verwendete Kolonne zur Argongewinnung und wird daher als Argonkolonne bezeichnet. Diese wird, wie eine Argonkolonne in einer klassischen Luftzerlegungsanlage, mit einem Seitenstrom aus der Niederdruckkolonne gespeist. Der Begriff "Seitenstrom" soll dabei einen Fluidstrom bezeichnen, der weder aus dem Sumpfbereich noch aus dem Kopfbereich, also Bereichen unterhalb des untersten bzw. oberhalb der obersten Trenneinrichtung (beispielsweise einem Trennboden oder einem Packungsbereich) entnommen werden, sondern dazwischen, d.h. zwischen zwei entsprechenden T renneinrichtungen. While the high pressure column, the low pressure column and the intermediate pressure column in the context of the present invention essentially serve to obtain oxygen and nitrogen-rich air products (top gas of the high pressure column is provided under a corresponding pressure as nitrogen pressure product and bottom liquid can be taken from the low pressure column as pure oxygen product), the Another column used in the present invention for the production of argon and is therefore referred to as an argon column. Like an argon column in a classic air separation plant, this is fed with a side stream from the low-pressure column. The term "side stream" is intended to denote a fluid stream that is taken neither from the sump area nor from the head area, i.e. areas below the lowest or above the uppermost separating device (for example a separating tray or a packing area), but between, ie between two corresponding ones Separation devices.
Zur Argongewinnung werden typischerweise Luftzerlegungsanlagen mit Doppelkolonnensystemen und sogenannten Roh- und ggf. sogenannten Reinargonkolonnen eingesetzt. Ein Beispiel ist bei Häring (s.o.) in Figur 2.3A veranschaulicht und ab Seite 26 im Abschnitt "Rectification in the Low-pressure, Crude and Pure Argon Column" sowie ab Seite 29 im Abschnitt "Cryogenic Production of Pure Argon" beschrieben. Grundsätzlich kann in entsprechenden Anlagen auch auf eine Reinargonkolonne verzichtet werden, wenn die betreffenden Rektifikationskolonnen entsprechend ausgebildet werden. Reinargon kann dann aus der Rohargonkolonne bzw. einer vergleichbaren Kolonne typischerweise etwas weiter unterhalb als das herkömmlicherweise in die Reinargonkolonne überführte Fluid abgezogen werden, wobei ein oberhalb liegender Trennbereich zur Abtrennung verbleibender Fremdkomponenten dient. Die im Rahmen der vorliegenden Erfindung eingesetzte Argonkolonne kann im Wesentlichen wie eine aus dem Stand der Technik bekannte, herkömmliche Rohargonkolonne (oder eine entsprechend modifizierte Rohargonkolonne) betrieben werden. Die Ausbildung entsprechender Argonkolonnen kann insbesondere mit entsprechender Bodenzahl erfolgen. Air separation plants with double column systems and so-called crude and possibly so-called pure argon columns are typically used to extract argon. An example is illustrated by Häring (see above) in Figure 2.3A and described from page 26 in the section "Rectification in the Low-pressure, Crude and Pure Argon Column" and from page 29 in the section "Cryogenic Production of Pure Argon". In principle, a pure argon column can also be dispensed with in corresponding plants if the rectification columns in question are designed accordingly. Pure argon can then be withdrawn from the crude argon column or a comparable column typically somewhat further below than the fluid conventionally transferred into the pure argon column, with a separation area located above for separation remaining foreign components is used. The argon column used in the context of the present invention can be operated essentially like a conventional crude argon column known from the prior art (or a correspondingly modified crude argon column). Corresponding argon columns can in particular be formed with a corresponding number of plates.
Merkmale und Vorteile der Erfindung Features and advantages of the invention
Die vorliegende Erfindung schlägt insgesamt ein Verfahren zur Tieftemperaturzerlegung von Luft vor, bei dem eine Luftzerlegungsanlage verwendet wird, die ein Kolonnensystem aufweist, das eine Hochdruckkolonne, eine Zwischendruckkolonne, eine Niederdruckkolonne und eine Argonkolonne umfasst. Wie bereits erwähnt, handelt es sich bei der im Rahmen der vorliegenden Erfindung eingesetzten Hochdruckkolonne um jene Kolonne, die grundsätzlich wie in einem herkömmlichen SPECTRA-Verfahren verwendete Kolonne betrieben wird. Overall, the present invention proposes a method for the low-temperature separation of air, in which an air separation plant is used which has a column system comprising a high pressure column, an intermediate pressure column, a low pressure column and an argon column. As already mentioned, the high pressure column used in the context of the present invention is that column which is basically operated like the column used in a conventional SPECTRA process.
Die Hoch-, die Zwischen- und die Niederdruckkolonne, die im Rahmen der vorliegenden Erfindung eingesetzt werden, zeichnen sich ferner durch ihre jeweiligen Betriebsdruckniveaus aus. Spezifische Werte werden weiter unten erläutert. Die Hochdruckkolonne wird im Rahmen der vorliegenden Erfindung dabei auf einem Druckniveau betrieben, das deutlich oberhalb des Druckniveaus einer herkömmlichen Hochdruckkolonne liegt. Auf diese Weise kann im Rahmen der vorliegenden Erfindung der Hochdruckkolonne ein Stickstoffprodukt entnommen werden, welches direkt auf einem entsprechenden Druckniveau bereitgestellt werden kann und keiner anschließenden Verdichtung im Kalten oder im Warmen bedarf. Die Bereitstellung eines entsprechenden Stickstoffdruckprodukts gestaltet sich daher im Rahmen der vorliegenden Erfindung apparativ und ggf. sicherheitstechnisch deutlich einfacher als in einer klassischen Luftzerlegungsanlage. The high, intermediate and low pressure columns which are used in the context of the present invention are also distinguished by their respective operating pressure levels. Specific values are explained below. In the context of the present invention, the high pressure column is operated at a pressure level which is significantly above the pressure level of a conventional high pressure column. In this way, in the context of the present invention, a nitrogen product can be removed from the high pressure column, which nitrogen product can be provided directly at a corresponding pressure level and does not require any subsequent compression in the cold or in the warm. In the context of the present invention, the provision of a corresponding pressurized nitrogen product is therefore significantly simpler in terms of apparatus and, if necessary, in terms of safety technology than in a classic air separation plant.
Die vorliegende Erfindung profitiert damit von den Vorteilen eines bekannten SPECTRA-Verfahrens. Im Gegensatz zu einem herkömmlichen SPECTRA-Verfahren ermöglicht die vorliegende Erfindung jedoch auch die Herstellung eines sauerstoffreichen Luftprodukts und eines argonreichen Luftprodukts, wozu die erwähnten weiteren Kolonnen eingesetzt werden. Insgesamt wird die Hochdruckkolonne im Rahmen der vorliegenden Erfindung auf einem ersten Druckniveau, die Zwischendruckkolonne auf einem zweiten Druckniveau unterhalb des ersten Druckniveaus und die Niederdruckkolonne auf einem dritten Druckniveau unterhalb des ersten und des zweiten Druckniveaus betrieben. Die Zwischendruckkolonne und die Niederdruckkolonne können dabei im Rahmen der vorliegenden Erfindung auch nach Art einer herkömmlichen Doppelkolonne einer Luftzerlegungsanlage zusammengefasst sein. Ein zur Kondensation von Kopfgas der Zwischendruckkolonne verwendeter Wärmetauscher kann dabei auch im Sumpf der Niederdruckkolonne angeordnet sein. The present invention thus benefits from the advantages of a known SPECTRA method. In contrast to a conventional SPECTRA process, however, the present invention also enables the production of an oxygen-rich air product and an argon-rich air product, for which the mentioned further columns are used. Overall, the high pressure column in the context of the present invention is operated at a first pressure level, the intermediate pressure column at a second pressure level below the first pressure level and the low pressure column at a third pressure level below the first and the second pressure level. In the context of the present invention, the intermediate pressure column and the low pressure column can also be combined in the manner of a conventional double column of an air separation plant. A heat exchanger used to condense top gas from the intermediate pressure column can also be arranged in the bottom of the low pressure column.
In einer herkömmlichen Luftzerlegungsanlage besteht das dort eingesetzte Doppelkolonnensystem aus einer Hochdruckkolonne und einer Niederdruckkolonne, wobei die Hochdruckkolonne im oben erläuterten Sinn unterhalb der Niederdruckkolonne angeordnet ist. Dies kann auch für die Zwischendruckkolonne (Anordnung unterhalb der Niederdruckkolonne) und die Niederdruckkolonne (Anordnung oberhalb der Zwischendruckkolonne) im Rahmen der vorliegenden Erfindung der Fall sein. Die vorliegende Erfindung ist jedoch auf eine derartige Anordnung nach Art einer Doppelsäule bzw. Doppelkolonne beschränkt. Die beiden Kolonnen (Zwischendruckkolonne und Niederdruckkolonne) können vielmehr auch in Form zweier getrennter Kolonnen ausgebildet sein. Der die Zwischendruckkolonne und die Niederdruckkolonne wärmetauschend verbindende Kondensator kann auch außerhalb der Niederdruckkolonne angeordnet sein. In a conventional air separation plant, the double column system used there consists of a high pressure column and a low pressure column, the high pressure column being arranged below the low pressure column in the sense explained above. This can also be the case for the intermediate pressure column (arrangement below the low pressure column) and the low pressure column (arrangement above the intermediate pressure column) in the context of the present invention. However, the present invention is limited to such an arrangement in the manner of a double column or double column. Rather, the two columns (intermediate pressure column and low pressure column) can also be designed in the form of two separate columns. The condenser connecting the intermediate pressure column and the low pressure column in a heat-exchanging manner can also be arranged outside the low pressure column.
Die Zwischendruckkolonne wird im Rahmen der vorliegenden Erfindung typischerweise auf einem Druckniveau betrieben, das einer herkömmlichen Hochdruckkolonne einer Luftzerlegungsanlage entspricht. Das Betriebsdruckniveau der Niederdruckkolonne entspricht ebenfalls dem üblichen Betriebsdruckniveau einer klassischen Niederdruckkolonne. In the context of the present invention, the intermediate pressure column is typically operated at a pressure level which corresponds to a conventional high pressure column of an air separation plant. The operating pressure level of the low pressure column also corresponds to the usual operating pressure level of a classic low pressure column.
Im Rahmen der vorliegenden Erfindung, das eine Variation eines bekannten SPECTRA-Verfahrens darstellt, wird aus Kopfgas der Hochdruckkolonne unter Verdampfung oder Teilverdampfung einer ersten Flüssigkeit, die der Hochdruckkolonne entnommen und auf ein Verdampfungsdruckniveau zwischen dem ersten und dem zweiten Druckniveau entspannt wird, ein Kondensat gebildet. Das Verdampfungsdruckniveau kann typischerweise bei 3 bis 7 bar liegen. Die Entspannung erfolgt damit in Form einer Teilentspannung auf ein überatmosphärisches Druckniveau, die eine weitere Entspannung auf ein tieferes Druckniveau zulässt. In the context of the present invention, which is a variation of a known SPECTRA process, a condensate is formed from overhead gas of the high pressure column with evaporation or partial evaporation of a first liquid which is taken from the high pressure column and expanded to an evaporation pressure level between the first and the second pressure level . The evaporation pressure level can typically be 3 to 7 bar. The Relaxation thus takes place in the form of partial relaxation to a superatmospheric pressure level, which allows further relaxation to a lower pressure level.
Das gebildete Kondensat wird als Rücklauf teilweise oder vollständig in die Hochdruckkolonne zurückgespeist. Ein Teil eines entsprechenden Kondensats kann auch als flüssiges, stickstoffreiches Luftprodukt aus einer entsprechenden Anlage ausgeleitet werden. Bei der Verdampfung der ersten Flüssigkeit wird ein erstes Gas gebildet, das teilweise oder vollständig auf das erste Druckniveau rückverdichtet und in die Hochdruckkolonne zurückgespeist wird. Dies stellt ein wesentliches Merkmal eines SPECTRA-Verfahrens dar. Die der Hochdruckkolonne entnommene erste Flüssigkeit, die im Rahmen der vorliegenden Erfindung entsprechend behandelt wird, kann dabei insbesondere eine Flüssigkeit sein, die der Hochdruckkolonne einige theoretische oder praktische Böden oberhalb des Sumpfs entnommen wird, die also, mit anderen Worten, in Form eines Seitenstroms aus der Hochdruckkolonne ausgeführt wird. The condensate formed is partially or completely fed back into the high pressure column as reflux. Part of a corresponding condensate can also be discharged from a corresponding system as a liquid, nitrogen-rich air product. When the first liquid is evaporated, a first gas is formed which is partially or completely recompressed to the first pressure level and fed back into the high-pressure column. This is an essential feature of a SPECTRA process. The first liquid withdrawn from the high pressure column, which is treated accordingly in the context of the present invention, can in particular be a liquid which is withdrawn from the high pressure column a few theoretical or practical trays above the bottom, which In other words, it is carried out in the form of a side stream from the high pressure column.
Während in einem klassischen SPECTRA-Verfahren, wie es in der eingangs zitierten Patentliteratur offenbart ist, ein weiterer Stoffstrom aus der Hochdruckkolonne entsprechend behandelt wird, ist dies im Rahmen der vorliegenden Erfindung typischerweise nicht der Fall. So erfolgt im Rahmen der vorliegenden Erfindung das Bilden des Kopfkondensats aus dem Kopfgas der Hochdruckkolonne unter Verdampfung oder Teilverdampfung einer zweiten Flüssigkeit, die der Zwischendruckkolonne entnommen und auf das Verdampfungsdruckniveau zwischen dem ersten und dem zweiten Druckniveau verdichtet wird. Bei der Verdampfung der zweiten Flüssigkeit im Zuge der Kondensation des Kopfgases wird ein zweites Gas gebildet, das teilweise oder vollständig auf das zweite Druckniveau entspannt und in die Zwischendruckkolonne zurückgespeist wird. While in a classic SPECTRA process, as disclosed in the patent literature cited at the outset, a further stream from the high pressure column is treated accordingly, this is typically not the case in the context of the present invention. Thus, within the scope of the present invention, the top condensate is formed from the top gas of the high pressure column with evaporation or partial evaporation of a second liquid which is taken from the intermediate pressure column and compressed to the evaporation pressure level between the first and the second pressure level. During the evaporation of the second liquid in the course of the condensation of the top gas, a second gas is formed, which is partially or completely expanded to the second pressure level and fed back into the intermediate pressure column.
Die vorliegende Erfindung schafft damit zwei Stoffkreisläufe, nämlich einmal den Stoffkreislauf, dem die erste Flüssigkeit aus der Hochdruckkolonne unterworfen wird, und einen zweiten Stoffkreislauf, dem eine Flüssigkeit aus der Zwischendruckkolonne unterworfen wird. Während der erste Kreislauf noch insoweit einem typischen SPECTRA-Verfahren entspricht, ist der zweite Kreislauf, wie erfindungsgemäß eingesetzt wird, neu gegenüber dem Stand der Technik. Um die zweite Flüssigkeit aus der Zwischendruckkolonne auf das Verdampfungsdruckniveau zu bringen, ist dabei typischerweise eine Pumpe vorgesehen, die eine Druckbeaufschlagung der zweiten Flüssigkeit in flüssigem Zustand vornimmt. Während die erste Flüssigkeit aus der Hochdruckkolonne typischerweise ein Seitenstrom aus der Hochdruckkolonne ist, wird die zweite Flüssigkeit aus der Zwischendruckkolonne hingegen unter Verwendung von Sumpfflüssigkeit gebildet. The present invention thus creates two material cycles, namely the material cycle to which the first liquid from the high pressure column is subjected and a second material cycle to which a liquid from the intermediate pressure column is subjected. While the first cycle still corresponds to a typical SPECTRA process, the second cycle, as used according to the invention, is new compared to the prior art. In order to bring the second liquid from the intermediate pressure column to the evaporation pressure level, a pump is typically provided which pressurizes the second liquid in the liquid state. While the first liquid from the high pressure column is typically a side stream from the high pressure column, the second liquid from the intermediate pressure column, on the other hand, is formed using bottom liquid.
Nicht sämtliche zweite Flüssigkeit aus der Zwischendruckkolonne muss in diese Zwischendruckkolonne zurückgeführt werden. Vielmehr ist in einer Ausgestaltung der vorliegenden Erfindung, die auch unter Bezugnahme auf die beigefügte Figur 1 erläutert wird, vorgesehen, einen Anteil des zweiten Gases, das bei der Verdampfung der zweiten Flüssigkeit gebildet wird, nicht in die Zwischendruckkolonne einzuspeisen, sondern, insbesondere in einer mit einem Verdichter, der zum Verdichten des ersten Gases eingesetzt wird, gekoppelten Entspannungsmaschine weiter zu entspannen und schließlich aus der Luftzerlegungsanlage auszuleiten. Not all of the second liquid from the intermediate pressure column has to be returned to this intermediate pressure column. Rather, in one embodiment of the present invention, which is also explained with reference to the attached FIG. 1, a portion of the second gas that is formed during the evaporation of the second liquid is not fed into the intermediate pressure column, but, in particular, into a with a compressor, which is used to compress the first gas, to expand the expansion machine coupled further and finally to discharge it from the air separation plant.
Zur jeweiligen Funktion der erfindungsgemäß eingesetzten Kolonnen sei nochmals betont, dass die Hochdruckkolonne insbesondere mit verdichteter und abgekühlter Einsatzluft gespeist wird. Dies schließt nicht aus, dass auch andere Kolonnen entsprechend mit Luft gespeist werden; stets ist dies jedoch im Fall der erfindungsgemäß eingesetzten Hochdruckkolonne vorgesehen. Regarding the respective function of the columns used according to the invention, it should be emphasized again that the high pressure column is fed in particular with compressed and cooled feed air. This does not rule out that other columns are also fed with air accordingly; However, this is always provided in the case of the high pressure column used according to the invention.
Im einer vorteilhaften Ausgestaltung der vorliegenden Erfindung wird Sumpfflüssigkeit aus der Hochdruckkolonne vom ersten auf das zweite Druckniveau entspannt und in die Zwischendruckkolonne eingespeist. Auch dies ist in herkömmlichen SPECTRA- Verfahren, auch wenn dort weitere Kolonnen verwendet werden, typischerweise nicht der Fall; ein entsprechender Stoffstrom, der unter Verwendung von Sumpfflüssigkeit gebildet wird, wird in derartigen herkömmlichen Verfahren vielmehr ebenfalls als Kühlmittel zur Kondensation von Kopfgas der entsprechenden Kolonne eingesetzt. In an advantageous embodiment of the present invention, bottom liquid from the high pressure column is expanded from the first to the second pressure level and fed into the intermediate pressure column. This is also typically not the case in conventional SPECTRA processes, even if further columns are used there; a corresponding stream of material, which is formed using bottom liquid, is also used in conventional processes of this kind as a coolant for the condensation of top gas of the corresponding column.
In dem erfindungsgemäß vorgeschlagenen Verfahren wird in einer vorteilhaften Ausgestaltung ein in flüssigem Zustand aus der Hochdruckkolonne entnommener Seitenstrom ferner teilweise oder vollständig von dem ersten auf das zweite Druckniveau entspannt und unter Bildung eines Flüssiganteils und eines Gasanteils einer Phasentrennung zugeführt. Der Flüssiganteil kann dabei insbesondere teilweise oder vollständig einer Trennung in der Niederdruckkolonne und der Gasanteil teilweise oder vollständig einer Trennung in der Zwischendruckkolonne unterworfen werden.In the method proposed according to the invention, in an advantageous embodiment, a side stream withdrawn from the high-pressure column in the liquid state is also partially or completely expanded from the first to the second pressure level and with the formation of a liquid component and a gas component fed to a phase separation. The liquid fraction can in particular be partially or completely subjected to a separation in the low-pressure column and the gas fraction can be partially or completely subjected to a separation in the intermediate-pressure column.
Eine besondere Ausgestaltung eines derartigen Verfahrens umfasst, den aus der Hochdruckkolonne entnommenen Seitenstrom oder dessen von dem ersten auf das zweite Druckniveau entspannten Anteil für die Phasentrennung in die Zwischendruckkolonne einzuspeisen, wo sich der Flüssiganteil flüssig, beispielsweise in einen Flüssigkeitsrückhaltebehälter oder auf einem Trennboden, abscheidet, und der Gasanteil direkt in die Gasphase übergeht. Auf diese Weise kann der Flüssiganteil teilweise oder vollständig der Zwischendruckkolonne wieder entnommen und in die Niederdruckkolonne eingespeist werden, wo dieser der dort erfolgenden Trennung unterworfen wird. Der Gasanteil wird in der Zwischendruckkolonne belassen und dort der Trennung unterworfen. A particular embodiment of such a process comprises feeding the side stream withdrawn from the high pressure column or its component, which has been expanded from the first to the second pressure level, for the phase separation into the intermediate pressure column, where the liquid component is deposited in liquid form, for example in a liquid retention container or on a separation tray, and the gas portion goes directly into the gas phase. In this way, the liquid fraction can be partially or completely withdrawn from the intermediate pressure column and fed into the low pressure column, where it is subjected to the separation that takes place there. The gas fraction is left in the intermediate pressure column and is subjected to separation there.
Wie erwähnt, wird im Rahmen einer vorteilhaften Ausgestaltung der vorliegenden Erfindung die eingesetzte Argonkolonne im Wesentlichen nach Art einer herkömmlichen Argonkolonne einer Luftzerlegungsanlage betrieben. Dies bedeutet, dass aus der Niederdruckkolonne auch im Rahmen der vorliegenden Erfindung ein an Argon angereicherter Seitenstrom entnommen wird, wobei zumindest ein Teil des zweiten Stroms aus der Niederdruckkolonne in die Argonkolonne eingespeist wird. Der an Argon angereicherte Seitenstrom weist insbesondere einen höheren Argongehalt auf als dieser am Kopf oder im Sumpf der Niederdruckkolonne vorliegt. Er wird an einer aus dem Bereich der Luftzerlegungsanlagen grundsätzlich bekannten und vorteilhaften Bereich aus der Niederdruckkolonne entnommen. As mentioned, in the context of an advantageous embodiment of the present invention, the argon column used is operated essentially in the manner of a conventional argon column of an air separation plant. This means that, within the scope of the present invention, an argon-enriched side stream is withdrawn from the low-pressure column, at least part of the second stream being fed from the low-pressure column into the argon column. The side stream enriched in argon has, in particular, a higher argon content than is present at the top or bottom of the low-pressure column. It is taken from the low-pressure column in an advantageous area known in principle from the area of air separation plants.
Im Rahmen der vorliegenden Erfindung wird vorteilhafterweise nicht der Seitenstrom direkt in die Argonkolonne eingespeist, sondern nur ein Teil hiervon dorthin überführt. Dies erfolgt vorteilhafterweise derart, dass ein Teil des Seitenstroms aus der Niederdruckkolonne in die Argonkolonne eingespeist wird, indem der Seitenstrom teilweise oder vollständig einer Sauerstoffkolonne zugeführt wird, in welcher ein gegenüber dem Seitenstrom an Argon angereicherter Stoffstrom gebildet wird, der seinerseits teilweise oder vollständig in die Argonkolonne eingespeist wird. In the context of the present invention, it is advantageous not to feed the side stream directly into the argon column, but rather only a part of it is transferred there. This is advantageously carried out in such a way that part of the side stream from the low-pressure column is fed into the argon column by partially or completely feeding the side stream to an oxygen column in which a material stream enriched in argon compared to the side stream is formed, which in turn partially or completely enters the Argon column is fed.
Im Rahmen einer vorteilhaften Ausgestaltung der vorliegenden Erfindung wird die Argonkolonne unter Verwendung eines Kopfkondensators betrieben. Dies bedeutet nichts anderes, als dass aus Kopfgas der Argonkolonne unter Teilverdampfung von Flüssigkeit ein Kondensat gebildet wird, das teilweise oder vollständig in die Argonkolonne zurückgespeist wird. Die Flüssigkeit, unter deren Teilverdampfung aus dem Kopfgas der Argonkolonne das Kondensat gebildet wird, wird dabei im Rahmen der vorliegenden Erfindung vorteilhafterweise aus der Zwischendruckkolonne entnommen, was einen weiteren grundsätzlichen Unterschied gegenüber bekannten Verfahren darstellt. Alternativ kann ein bei der Teilverdampfung gebildetes Gas und/oder bei der Teilverdampfung verbleibende Flüssigkeit teilweise oder vollständig in die Niederdruckkolonne eingespeist werden. In the context of an advantageous embodiment of the present invention, the argon column is operated using a top condenser. this means nothing else than that a condensate is formed from the top gas of the argon column with partial evaporation of liquid, which is partially or completely fed back into the argon column. The liquid, with the partial evaporation of which the condensate is formed from the top gas of the argon column, is advantageously removed from the intermediate pressure column within the scope of the present invention, which represents a further fundamental difference compared to known processes. Alternatively, a gas formed in the partial evaporation and / or liquid remaining in the partial evaporation can be fed partially or completely into the low-pressure column.
Im Rahmen der vorliegenden Erfindung können, wie grundsätzlich im SPECTRA- Verfahren bekannt, mit Verdichtern gekoppelte Expander eingesetzt werden. So kann hier zum Rückverdichten des ersten Gases oder von dessen Anteil, der auf das erste Druckniveau rückverdichtet und in die Hochdruckkolonne zurückgespeist wird, ein Verdichter verwendet werden, der mechanisch mit einer Entspannungsmaschine gekoppelt ist, die zum Entspannen eines weiteren Anteils des zweiten Gases, der nicht in die Zwischendruckkolonne zurückgespeist wird, verwendet wird. In the context of the present invention, as is fundamentally known in the SPECTRA process, expanders coupled with compressors can be used. For example, to recompress the first gas or its portion that is recompressed to the first pressure level and fed back into the high pressure column, a compressor can be used that is mechanically coupled to an expansion machine that is used to depressurize a further portion of the second gas, the is not fed back into the intermediate pressure column is used.
Die vorliegende Erfindung erstreckt sich ferner auf eine Luftzerlegungsanlage, zu deren spezifischen Merkmalen auf den entsprechenden unabhängigen Patentanspruch verwiesen wird. Zu weiteren Merkmalen und Ausgestaltungen einer derartigen Anlage und von bevorzugten Ausführungsformen sei auf die obigen Erläuterungen bezüglich des erfindungsgemäßen Verfahrens und seiner jeweiligen vorteilhaften Ausgestaltungen ausdrücklich verwiesen. Vorteilhafterweise ist eine derartige Luftzerlegungsanlage zur Durchführung eines Verfahrens eingerichtet, wie es zuvor in unterschiedlichen Ausgestaltungen erläutert wurde. The present invention also extends to an air separation plant, for the specific features of which reference is made to the corresponding independent patent claim. For further features and configurations of such a system and of preferred embodiments, express reference is made to the above explanations relating to the method according to the invention and its respective advantageous configurations. Such an air separation plant is advantageously set up to carry out a method as has been explained above in different configurations.
Die vorliegende Erfindung wird nachfolgend unter Bezugnahme auf die beigefügten Zeichnungen, die eine Luftzerlegungsanlage gemäß einer Ausgestaltung der vorliegenden Erfindung veranschaulichen, näher erläutert. The present invention is explained in more detail below with reference to the accompanying drawings, which illustrate an air separation plant according to an embodiment of the present invention.
Kurze Beschreibung der Zeichnungen Brief description of the drawings
Figur 1 veranschaulicht eine Luftzerlegungsanlage gemäß einer Ausgestaltung der vorliegenden Erfindung in Form eines vereinfachten Prozessflussdiagramms. Ausführliche Beschreibung der Zeichnungen FIG. 1 illustrates an air separation plant according to an embodiment of the present invention in the form of a simplified process flow diagram. Detailed description of the drawings
In Figur 1 ist eine Luftzerlegungsanlage gemäß einer besonders bevorzugten Ausführungsform der vorliegenden Erfindung in Form eines stark vereinfachten, schematischen Prozessflussdiagramms dargestellt und insgesamt mit 100 bezeichnet. In FIG. 1, an air separation plant according to a particularly preferred embodiment of the present invention is shown in the form of a greatly simplified, schematic process flow diagram and denoted as a whole by 100.
Der in Figur 1 veranschaulichten Luftzerlegungsanlage 100 wird über einen Filter 101 mittels eines insbesondere mehrstufig und mit Zwischenkühlung ausgebildeten Hauptluftverdichters 102 aus der hier mit allgemein mit A bezeichneten Atmosphäre Luft angesaugt. Nach einer Nachkühlung in Wärmetauschern 103 und 104 wird ein auf diese Weise gebildeter Einsatzluftstrom a in einem mit Wasser W betriebenen Direktkontaktkühler 105 gekühlt und anschließend einer Adsorptionseinrichtung 106 zugeführt. The air separation plant 100 illustrated in FIG. 1 is sucked in air from the atmosphere, here denoted generally by A, via a filter 101 by means of a main air compressor 102, which is in particular multi-stage and with intermediate cooling. After after-cooling in heat exchangers 103 and 104, a feed air stream a formed in this way is cooled in a direct contact cooler 105 operated with water W and then fed to an adsorption device 106.
Nachdem der Einsatzluftstrom a auf diese Weise getrocknet und im Wesentlichen von Kohlendioxid befreit wurde, wird dieser einem Hauptwärmetauscher 107 zugeführt. Der Einsatzluftstrom a wird dem Hauptwärmetauscher nahe dessen kaltem Ende entnommen und im hier veranschaulichten Beispiel im Wesentlichen der Hochdruckkolonne 11 eines insgesamt mit 10 bezeichneten Kolonnensystems zugeführt. Ein nicht gesondert veranschaulichter Teil kann über einen Bypass bei Bedarf abgezweigt werden. After the feed air stream a has been dried in this way and essentially freed from carbon dioxide, it is fed to a main heat exchanger 107. The feed air stream a is taken from the main heat exchanger near its cold end and, in the example illustrated here, is essentially fed to the high pressure column 11 of a column system designated overall by 10. A part that is not shown separately can be branched off via a bypass if required.
Ein Kopfstrom b der Hochdruckkolonne 11 kann zu einem Teil in Form eines Stoffstroms c als gasförmiges Druckstickstoffprodukt aus der Luftzerlegungsanlage 100 ausgeleitet werden. Entsprechende Druckstickstoffprodukte sind nochmals mit C1 und C2 bezeichnet. Ein nicht auf diese Weise aus der Luftzerlegungsanlage ausgeleiteter Anteil des Kopfstroms b wird hingegen im hier veranschaulichten Beispiel in Form eines Stoffstroms d einem Wärmetauscher bzw. Kondensator 108 zugeführt und dort im Wesentlichen kondensiert. Entsprechendes Kondensat kann zu einem Teil in Form eines Stoffstroms e als flüssiger Rücklauf auf die Hochdruckkolonne 11 zurückgeführt werden. Ein weiterer Anteil wird in Form eines Spülstroms P entnommen. Bei Bedarf kann auch Flüssigstickstoff E in die Anlage 100 in der hier veranschaulichten Weise eingespeist werden. Ein weiterer Anteil kann in Form eines Stoffstroms f in einem Unterkühler 109 unterkühlt und als Flüssigstickstoffprodukt F aus der Anlage ausgeleitet werden. Ein zum Unterkühlen verwendeter, stromab des Unterkühlers 109 abgezweigter Anteil wird als Restgas aus der Anlage ausgeleitet, wie nachfolgend auch unter Bezugnahme auf weitere Stoffströme erläutert. A top stream b of the high pressure column 11 can be discharged from the air separation plant 100 in part in the form of a stream c as a gaseous pressurized nitrogen product. Corresponding pressurized nitrogen products are again labeled C1 and C2. In contrast, in the example illustrated here, a portion of the top stream b that is not diverted from the air separation plant is fed to a heat exchanger or condenser 108 in the form of a material stream d and is essentially condensed there. A portion of the corresponding condensate can be returned to the high pressure column 11 as a liquid reflux in the form of a stream e. Another portion is withdrawn in the form of a flushing flow P. If necessary, liquid nitrogen E can also be fed into the system 100 in the manner illustrated here. Another portion can be subcooled in the form of a material flow f in a subcooler 109 and as a liquid nitrogen product F from the system be diverted. A portion that is used for subcooling and is branched off downstream of subcooler 109 is discharged from the system as residual gas, as also explained below with reference to further material flows.
Eine Zwischendruckkolonne 12 des Kolonnensystems 10 wird im dargestellten Beispiel mittels eines Sumpfstroms g der Hochdruckkolonne 11 gespeist. Dieser Sumpfstrom g wird dazu in dem Hauptwärmetauscher 107 abgekühlt und anschließend oberhalb des Sumpfs bzw. oberhalb einiger Trennböden, die oberhalb des Sumpfs liegen, in die Zwischendruckkolonne eingespeist. In the example shown, an intermediate pressure column 12 of the column system 10 is fed by means of a bottom stream g of the high pressure column 11. For this purpose, this bottom stream g is cooled in the main heat exchanger 107 and then fed into the intermediate pressure column above the bottom or above some separating trays which are above the bottom.
Eine weitere Speisung der Zwischendruckkolonne erfolgt mittels eines Seitenstroms h aus der Hochdruckkolonne 11 , welcher in die Zwischendruckkolonne 12 entspannt wird. Auf diese Weise gebildetes Gas wird in der Zwischendruckkolonne 12 belassen; dagegen hingegen wird Flüssigkeit in Form eines Stoffstroms i direkt unterhalb der Einspeisestelle zumindest zum Teil wieder aus der Zwischendruckkolonne 12 entnommen und zunächst durch einen Unterkühler 110 geführt und anschließend in eine Niederdruckkolonne 13 des Kolonnensystems 10 eingespeist. The intermediate pressure column is further fed by means of a side stream h from the high pressure column 11, which is depressurized into the intermediate pressure column 12. Gas formed in this way is left in the intermediate pressure column 12; on the other hand, liquid in the form of a stream i is at least partially withdrawn from the intermediate pressure column 12 directly below the feed point and first passed through a subcooler 110 and then fed into a low pressure column 13 of the column system 10.
Der Wärmetauscher 108 wird zunächst unter Verwendung eines aus der Hochdruckkolonne entnommenen Seitenstroms k betrieben. Dieser wird zuerst im Hauptwärmetauscher 107 weiter abgekühlt und danach dem Wärmetauscher 108 zugeführt. Dabei erfolgt eine Teilentspannung. Stromab des Wärmetauschers 108 kann ein Teil des entsprechend verdampften Fluides an die Atmosphäre A abgegeben werden. Ein weiterer Teil wird, wie hier weiterhin in Form eines Stoffstroms k veranschaulicht, ggf. nach Vereinigung mit weiteren Stoffströmen, in einem Verdichter 111 , der mit einer Entspannungsmaschine 112 mechanisch gekoppelt und zusätzlich mittels einer dissipativen Bremse gebremst wird, rückverdichtet. Der Stoffstrom k kann auf diese Weise erneut in die Hochdruckkolonne 11 eingespeist werden. Weitere Kälteleistung für den Wärmetauscher 108 wird durch einen Sumpfstrom I der Zwischendruckkolonne 12 bereitgestellt. Dieser wird dazu mittels einer Pumpe 113 auf ein in dem Wärmetauscher 108 erforderliches Druckniveau gebracht. The heat exchanger 108 is initially operated using a side stream k withdrawn from the high pressure column. This is first cooled further in the main heat exchanger 107 and then fed to the heat exchanger 108. Partial relaxation takes place. Downstream of the heat exchanger 108, part of the correspondingly evaporated fluid can be released into atmosphere A. Another part is recompressed, as further illustrated here in the form of a material flow k, possibly after combining with other material flows, in a compressor 111, which is mechanically coupled to an expansion machine 112 and additionally braked by means of a dissipative brake. The stream k can be fed into the high pressure column 11 again in this way. Further cooling capacity for the heat exchanger 108 is provided by a bottom stream I of the intermediate pressure column 12. For this purpose, this is brought to a pressure level required in the heat exchanger 108 by means of a pump 113.
Der Stoffstrom I wird, nachdem er in dem Wärmetauscher 108 verdampft wurde, in Form eines ersten Teilstroms m im Hauptwärmetauscher 107 erwärmt und zumindest zum Teil in der Entspannungsmaschine 112 entspannt. Dieser Stoffstrom wird anschließend, insbesondere zusammen mit dem in dem Unterkühler 109 zur Kühlung verwendeten Anteil des Kopfstroms b aus der Hochdruckkolonne aus der Anlage ausgeleitet. Ein weiterer Anteil n des in dem Wärmetauscher 108 verdampften Sumpfstroms aus der Zwischendruckkolonne 12 wird hingegen in die Zwischendruckkolonne 12 zurückgeführt. After it has been evaporated in the heat exchanger 108, the material flow I is heated in the form of a first partial flow m in the main heat exchanger 107 and at least partially expanded in the expansion machine 112. This material flow is then, in particular together with the portion of the overhead stream b used for cooling in the subcooler 109, discharged from the high pressure column from the plant. A further portion n of the bottom stream from the intermediate pressure column 12 evaporated in the heat exchanger 108, on the other hand, is returned to the intermediate pressure column 12.
Die Luftzerlegungsanlage 100 umfasst ferner eine Argonkolonne 14, die letztlich aus der Niederdruckkolonne 13 bzw. mittels eines der Niederdruckkolonne 13 entnommenen Seitenstroms o gespeist wird. Der Seitenstrom o wird jedoch in dem dargestellten Beispiel nicht direkt in die Argonkolonne 14 überführt, sondern zunächst in einen oberen Teil 15a einer insgesamt mit 15 bezeichneten Sauerstoffkolonne überführt. In dem oberen Teil 15a wird der Stoffstrom o bzw. das auf diese Weise in den oberen Teil 15a überführte Fluid weiter an Argon angereichert und an Sauerstoff abgereichert, so dass vom Kopf des oberen Teils 15a ein entsprechender Stoffstrom p in die Argonkolonne 14 überführt werden kann. Sumpfflüssigkeit aus der Argonkolonne 14 wird über eine hier nicht gesondert bezeichnete Pumpe in den oberen Teil 15a der Sauerstoffkolonne zurückgeführt. The air separation plant 100 further comprises an argon column 14, which is ultimately fed from the low-pressure column 13 or by means of a side stream o withdrawn from the low-pressure column 13. However, in the example shown, the side stream o is not transferred directly to the argon column 14, but instead is first transferred to an upper part 15a of an oxygen column designated as a whole by 15. In the upper part 15a, the stream o or the fluid transferred in this way to the upper part 15a is further enriched in argon and depleted in oxygen, so that a corresponding stream p can be transferred from the top of the upper part 15a to the argon column 14 . Bottom liquid from the argon column 14 is returned to the upper part 15a of the oxygen column via a pump, which is not specifically designated here.
Die Sauerstoffkolonne 15 mit dem oberen Teil 15a und dem unteren Teil 15b wird mit einem Sumpfverdampfer 151 betrieben. Dieser Sumpfverdampfer 151 , und ein im Sumpf der Niederdruckkolonne 13 angeordneter Sumpfverdampfer 131 , werden jeweils zum Kondensieren von Kopfgas der Zwischendruckkolonne 12 verwendet, das dieser in Form eines Stoffstroms q entnommen wird. Ein kondensierter Anteil wird, wie hier nicht gesondert und individuell veranschaulicht, im Wesentlichen als Rücklauf auf die Zwischendruckkolonne 12 und auf die Niederdruckkolonne 13 verwendet. The oxygen column 15 with the upper part 15a and the lower part 15b is operated with a bottom evaporator 151. This bottom evaporator 151, and a bottom evaporator 131 arranged in the bottom of the low-pressure column 13, are each used to condense top gas from the intermediate pressure column 12, which gas is withdrawn from it in the form of a stream q. A condensed portion is, as not illustrated separately and individually here, essentially used as reflux to the intermediate pressure column 12 and to the low pressure column 13.
Vom Kopf der Niederdruckkolonne 13 wird ein Stoffstrom r abgezogen und in Form von Unreinsauerstoff nach Erwärmung an die Atmosphäre abgeblasen bzw. auf andere Weise verwendet. A stream r is withdrawn from the top of the low-pressure column 13 and blown off in the form of impure oxygen after heating to the atmosphere or used in another way.
Aus dem Sumpf der Niederdruckkolonne 13 werden Sauerstoffströme s und t entnommen, wobei der Sauerstoffstrom s in einer nicht gesondert bezeichneten Pumpe innenverdichtet und zur Bereitstellung eines entsprechenden Innenverdichtungsprodukts S verwendet werden kann. Der Sauerstoffstrom t kann hingegen erwärmt und aus der Anlage ausgeführt bzw. an die Atmosphäre abgegeben werden. Ein Teil kann, wie hier in Form einer Verknüpfung X veranschaulicht, in die Niederdruckkolonne 13 zurückgeführt werden. Oxygen streams s and t are withdrawn from the bottom of the low-pressure column 13, with the oxygen stream s being internally compressed in a pump, which is not specifically designated, and can be used to provide a corresponding internal compression product S. The oxygen flow t, on the other hand, can be heated and discharged from the system or released into the atmosphere become. A part can, as illustrated here in the form of a link X, be returned to the low-pressure column 13.
Die Argonkolonne 14, deren Kopf mittels eines Kopfkondensators 141 gekühlt wird, kann zur Bereitstellung eines Flüssigargonstroms u verwendet werden, welcher, beispielsweise nach Zwischenspeicherung in einem Tanksystem T als innenverdichtetes Argonprodukt U bereitgestellt werden kann. Ein Teil hiervon kann auch in einem Speichertank T1 dauerhaft eingespeichert und beispielsweise flüssig aus der Anlage ausgeführt werden. The argon column 14, the top of which is cooled by means of a top condenser 141, can be used to provide a liquid argon stream u, which can be provided as an internally compressed argon product U, for example after being temporarily stored in a tank system T. A part of this can also be stored permanently in a storage tank T1 and, for example, can be run out of the system in liquid form.
Der Kopfkondensator 141 der Argonkolonne 14 wird im hier veranschaulichten Beispiel unter Verwendung eines Stoffstroms v gekühlt, der einige Böden oberhalb des Sumpfs aus der Zwischendruckkolonne 12 flüssig entnommen und in einen Verdampfungsraum des Argonkondensators 141 eingespeist wird. Hier verdampfte bzw. unverdampfte Anteile können in der veranschaulichten Weise in die Niederdruckkolonne zurückgeführt werden. In the example illustrated here, the top condenser 141 of the argon column 14 is cooled using a stream v which is withdrawn in liquid form from the intermediate pressure column 12 a few floors above the sump and fed into an evaporation chamber of the argon condenser 141. Fractions that have evaporated or that have not been evaporated here can be returned to the low-pressure column in the manner illustrated.
Der obere Teil 15a und der untere Teil 15b der Sauerstoffkolonne 15 sind fluidisch miteinander gekoppelt, wie hier in Form entsprechender Fluidpfeile veranschaulicht. An Argon abgereichertes und an Sauerstoff angereichertes Fluid wird aus dem oberen Teil 15a in den unteren Teil 15b überführt und dort weiter rektifiziert. Auf diese Weise lässt sich dem Sumpf der Sauerstoffkolonne 15 bzw. deren unteren Teils ein Reinsauerstoffstrom w entnehmen, der ebenfalls über ein entsprechendes Tanksystem t2 bzw. t3 als Flochreinsauerstoffprodukt W in innenverdichteter Form aus der Luftzerlegungsanlage 100 ausgeführt werden kann. Weitere hier veranschaulichte Stoffströme und deren spezifische Behandlung in der Luftzerlegungsanlage 100 ergeben sich unmittelbar aus der Zeichnung. The upper part 15a and the lower part 15b of the oxygen column 15 are fluidically coupled to one another, as illustrated here in the form of corresponding fluid arrows. Fluid depleted in argon and enriched in oxygen is transferred from the upper part 15a to the lower part 15b, where it is further rectified. In this way, a pure oxygen stream w can be taken from the bottom of the oxygen column 15 or its lower part, which can also be carried out from the air separation plant 100 as a pure oxygen product W in internally compressed form via a corresponding tank system t2 or t3. Further material flows illustrated here and their specific treatment in the air separation plant 100 result directly from the drawing.

Claims

Patentansprüche Claims
1. Verfahren zur Tieftemperaturzerlegung von Luft, bei dem 1. Process for the cryogenic separation of air, in which
- eine Luftzerlegungsanlage (100) verwendet wird, die ein Kolonnensystem (10) aufweist, das eine Hochdruckkolonne (11), eine Zwischendruckkolonne (12), eine Niederdruckkolonne (13) und eine Argonkolonne (14) umfasst, - an air separation plant (100) is used which has a column system (10) which comprises a high pressure column (11), an intermediate pressure column (12), a low pressure column (13) and an argon column (14),
- die Hochdruckkolonne (11) auf einem ersten Druckniveau, die Zwischendruckkolonne (12) auf einem zweiten Druckniveau unterhalb des ersten Druckniveaus und die Niederdruckkolonne (13) auf einem dritten Druckniveau unterhalb des zweiten Druckniveaus betrieben wird, - The high pressure column (11) is operated at a first pressure level, the intermediate pressure column (12) is operated at a second pressure level below the first pressure level and the low pressure column (13) is operated at a third pressure level below the second pressure level,
- die Hochdruckkolonne (11 ) mit verdichteter und abgekühlter Luft gespeist wird, und - The high pressure column (11) is fed with compressed and cooled air, and
- aus Kopfgas der Hochdruckkolonne (11) unter Verdampfung oder Teilverdampfung einer ersten Flüssigkeit, die der Hochdruckkolonne (11) entnommen und auf ein Verdampfungsdruckniveau zwischen dem ersten und dem zweiten Druckniveau entspannt wird, ein Kondensat gebildet und teilweise oder vollständig in die Hochdruckkolonne (11) zurückgespeist wird, wobei bei der Verdampfung der ersten Flüssigkeit ein erstes Gas gebildet wird, das teilweise oder vollständig auf das erste Druckniveau rückverdichtet und in die Hochdruckkolonne (11) zurückgespeist wird, dadurch gekennzeichnet, dass - From top gas of the high pressure column (11) with evaporation or partial evaporation of a first liquid, which is taken from the high pressure column (11) and expanded to an evaporation pressure level between the first and the second pressure level, a condensate is formed and partially or completely in the high pressure column (11) is fed back, with the evaporation of the first liquid forming a first gas which is partially or completely recompressed to the first pressure level and fed back into the high pressure column (11), characterized in that
- das Bilden des Kondensats aus dem Kopfgas der Hochdruckkolonne (11) unter Verdampfung oder Teilverdampfung einer zweiten Flüssigkeit erfolgt, die der Zwischendruckkolonne (12) entnommen und auf das Verdampfungsdruckniveau zwischen dem ersten und dem zweiten Druckniveau gebracht wird, und bei der Verdampfung der zweiten Flüssigkeit ein zweites Gas gebildet wird, das teilweise oder vollständig auf das zweite Druckniveau entspannt und in die Zwischendruckkolonne (11) zurückgespeist wird. - The formation of the condensate from the top gas of the high pressure column (11) takes place with evaporation or partial evaporation of a second liquid which is taken from the intermediate pressure column (12) and brought to the evaporation pressure level between the first and the second pressure level, and during the evaporation of the second liquid, a second gas is formed, which is partially or completely expanded to the second pressure level and fed back into the intermediate pressure column (11).
2. Verfahren nach Anspruch 1 , bei dem Sumpfflüssigkeit aus der Hochdruckkolonne (11) von dem ersten auf das zweite Druckniveau entspannt und in die Zwischendruckkolonne (12) eingespeist wird. 2. The method according to claim 1, in which the bottom liquid from the high pressure column (11) is expanded from the first to the second pressure level and is fed into the intermediate pressure column (12).
3. Verfahren Anspruch 1 oder 2, bei dem ein in flüssigem Zustand aus der Hochdruckkolonne (11) entnommener Seitenstrom teilweise oder vollständig von dem ersten auf das zweite Druckniveau entspannt und unter Bildung eines Flüssiganteils und eines Gasanteils einer Phasentrennung zugeführt wird, wobei der Flüssiganteil teilweise oder vollständig einer Trennung in der Niederdruckkolonne (13) und der Gasanteil teilweise oder vollständig einer Trennung in der Zwischendruckkolonne (12) unterworfen wird. 3. The method of claim 1 or 2, in which a side stream withdrawn in the liquid state from the high pressure column (11) is partially or completely expanded from the first to the second pressure level and fed to a phase separation with the formation of a liquid component and a gas component, the liquid component being partially or completely to a separation in the low-pressure column (13) and the gas fraction is partially or completely subjected to a separation in the intermediate-pressure column (12).
4. Verfahren nach Anspruch 3, bei dem der der Hochdruckkolonne (11) entnommene Seitenstrom oder dessen von dem ersten auf das zweite Druckniveau entspannter Anteil für die Phasentrennung in die Zwischendruckkolonne (12) eingespeist wird, wobei der Flüssiganteil teilweise oder vollständig der Zwischendruckkolonne (12) wieder entnommen und in die Niederdruckkolonne (13) eingespeist wird, und wobei der Gasanteil in der Zwischendruckkolonne (12) belassen wird. 4. The method according to claim 3, in which the side stream withdrawn from the high pressure column (11) or its portion which has been depressurized from the first to the second pressure level is fed into the intermediate pressure column (12) for the phase separation, the liquid portion partially or completely in the intermediate pressure column (12) ) is withdrawn again and fed into the low-pressure column (13), and the gas portion is left in the intermediate-pressure column (12).
5. Verfahren nach einem der vorstehenden Ansprüche, bei dem der Niederdruckkolonne (13) ein an Argon angereicherter Seitenstrom entnommen wird, wobei zumindest ein Teil des Seitenstroms aus der Niederdruckkolonne (13) in die Argonkolonne (14) eingespeist wird. 5. The method according to any one of the preceding claims, wherein a side stream enriched in argon is withdrawn from the low pressure column (13), at least part of the side stream from the low pressure column (13) being fed into the argon column (14).
6. Verfahren nach Anspruch 5, bei dem ein Teil des Seitenstroms aus der Niederdruckkolonne (13) in die Argonkolonne (14) eingespeist wird, indem der Seitenstrom teilweise oder vollständig einer Sauerstoffkolonne (15) zugeführt wird, in der ein gegenüber dem Seitenstrom an Argon angereicherter Stoffstrom gebildet wird, der teilweise oder vollständig in die Argonkolone (14) überführt wird. 6. The method according to claim 5, wherein part of the side stream from the low-pressure column (13) is fed into the argon column (14) by the side stream is partially or completely fed to an oxygen column (15) in which an opposite to the side stream of argon enriched stream is formed, which is partially or completely transferred into the argon column (14).
7. Verfahren nach einem der vorstehenden Ansprüche, bei dem aus Kopfgas der Argonkolonne (14) unter Teilverdampfung von Flüssigkeit ein Kondensat gebildet wird, das teilweise oder vollständig in die Argonkolonne (14) zurückgespeist wird, wobei die Flüssigkeit, unter deren Teilverdampfung aus dem Kopfgas der Argonkolonne (14) das Kondensat gebildet wird, aus der Zwischendruckkolonne (12) entnommen wird oder wobei ein bei der Teilverdampfung gebildete Gas und/oder eine bei der Teilverdampfung verbleibende Flüssigkeit teilweise oder vollständig in die Niederdruckkolonne (13) eingespeist wird. 7. The method according to any one of the preceding claims, in which a condensate is formed from the top gas of the argon column (14) with partial evaporation of liquid, which is partially or completely fed back into the argon column (14), the liquid, with its partial evaporation from the top gas the argon column (14) the condensate is formed, is removed from the intermediate pressure column (12) or a gas formed during partial evaporation and / or a liquid remaining during partial evaporation is partially or completely fed into the low-pressure column (13).
8. Verfahren nach einem der vorstehenden Ansprüche, bei dem zum Rückverdichten des ersten Gases oder von dessen Anteil, der auf das erste Druckniveau rückverdichtet und in die Flochdruckkolonne (11) zurückgespeist wird, ein Verdichter verwendet wird, der mechanisch mit einer Entspannungsmaschine gekoppelt ist, die zum Entspannen eines weiteren Anteils des zweiten Gases der nicht in die Zwischendruckkolonne (11) zurückgespeist wird, verwendet wird. 8. The method according to any one of the preceding claims, in which a compressor is used which is mechanically coupled to an expansion machine to recompress the first gas or its portion that is recompressed to the first pressure level and fed back into the floch pressure column (11), which is used to relax a further portion of the second gas which is not fed back into the intermediate pressure column (11).
9. Luftzerlegungsanlage (100), die ein Kolonnensystem (10) aufweist, das eine Flochdruckkolonne (11), eine Zwischendruckkolonne (12), eine Niederdruckkolonne (13) und eine Argonkolonne (14) umfasst, wobei die Luftzerlegungsanlage (100) dafür eingerichtet ist, 9. Air separation plant (100) which has a column system (10) which comprises a floch pressure column (11), an intermediate pressure column (12), a low pressure column (13) and an argon column (14), the air separation plant (100) being set up for this ,
- die Flochdruckkolonne (11) auf einem ersten Druckniveau, die Zwischendruckkolonne (12) auf einem zweiten Druckniveau unterhalb des ersten Druckniveaus und die Niederdruckkolonne (13) auf einem dritten Druckniveau unterhalb des ersten und zweiten Druckniveaus zu betreiben, - to operate the floch pressure column (11) at a first pressure level, the intermediate pressure column (12) at a second pressure level below the first pressure level and the low pressure column (13) at a third pressure level below the first and second pressure levels,
- die Flochdruckkolonne (11) mit verdichteter und abgekühlter Luft zu speisen, - to feed the floch pressure column (11) with compressed and cooled air,
- aus Kopfgas der Flochdruckkolonne (11) unter Verdampfung oder Teilverdampfung einer ersten Flüssigkeit, die der Flochdruckkolonne (11) entnommen und auf ein Verdampfungsdruckniveau zwischen dem ersten und dem zweiten Druckniveau entspannt wird, ein Kondensat zu bilden und teilweise oder vollständig in die Flochdruckkolonne (11) zurückzuspeisen, und bei der Verdampfung der ersten Flüssigkeit gebildetes erstes Gas teilweise oder vollständig auf das erste Druckniveau rückzuverdichten und in die Hochdruckkolonne (11) zurückzuspeisen, gekennzeichnet durch Mittel, die dafür eingerichtet sind, zum Bilden des Kondensats aus dem Kopfgas der Hochdruckkolonne (11) eine Verdampfung oder Teilverdampfung einer zweiten Flüssigkeit vorzunehmen, die der Zwischendruckkolonne (12) entnommen und auf das Verdampfungsdruckniveau zwischen dem ersten und dem zweiten Druckniveau verdichtet wird, und ein bei der Verdampfung der zweiten- From top gas of the floch pressure column (11) with evaporation or partial evaporation of a first liquid, which is taken from the floch pressure column (11) and expanded to an evaporation pressure level between the first and the second pressure level, to form a condensate and partially or completely in the floch pressure column (11 ) to feed back, and partially formed first gas during the evaporation of the first liquid or to completely recompress to the first pressure level and to feed it back into the high pressure column (11), characterized by means which are set up to carry out an evaporation or partial evaporation of a second liquid which is supplied to the intermediate pressure column (11) to form the condensate from the top gas of the high pressure column (11) 12) is removed and compressed to the evaporation pressure level between the first and the second pressure level, and one in the evaporation of the second
Flüssigkeit gebildetes zweites Gas teilweise oder vollständig auf das zweite Druckniveau zu entspannen und in die Zwischendruckkolonne (11) zurückzuspeisen. To partially or completely relax the second gas formed in the liquid to the second pressure level and to feed it back into the intermediate pressure column (11).
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