Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
  • F25J3/04763—Start-up or control of the process; Details of the apparatus used
  • F25J3/04769—Operation, control and regulation of the process; Instrumentation within the process
  • F25J3/04854—Safety aspects of operation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
  • F25J3/04006—Providing pressurised feed air or process streams within or from the air fractionation unit
  • F25J3/04078—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression
  • F25J3/0409—Providing pressurised feed air or process streams within or from the air fractionation unit providing pressurized products by liquid compression and vaporisation with cold recovery, i.e. so-called internal compression of oxygen
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
  • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
  • F25J3/04284—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion using internal refrigeration by open-loop gas work expansion, e.g. of intermediate or oxygen enriched (waste-)streams
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
  • F25J3/04248—Generation of cold for compensating heat leaks or liquid production, e.g. by Joule-Thompson expansion
  • F25J3/04333—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
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
  • F25J3/04406—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system
  • F25J3/04412—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air using a dual pressure main column system in a classical double column flowsheet, i.e. with thermal coupling by a main reboiler-condenser in the bottom of low pressure respectively top of high pressure column
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
  • F25J3/04642—Recovering noble gases from air
  • F25J3/04745—Krypton and/or Xenon
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/04—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream for air
  • F25J3/04763—Start-up or control of the process; Details of the apparatus used
  • F25J3/04866—Construction and layout of air fractionation equipments, e.g. valves, machines
  • F25J3/04969—Retrofitting or revamping of an existing air fractionation unit
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2200/00—Processes or apparatus using separation by rectification
  • F25J2200/32—Processes or apparatus using separation by rectification using a side column fed by a stream from the high pressure column
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2200/00—Processes or apparatus using separation by rectification
  • F25J2200/34—Processes or apparatus using separation by rectification using a side column fed by a stream from the low pressure column
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2200/00—Processes or apparatus using separation by rectification
  • F25J2200/90—Details relating to column internals, e.g. structured packing, gas or liquid distribution
  • F25J2200/94—Details relating to the withdrawal point
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2205/00—Processes or apparatus using other separation and/or other processing means
  • F25J2205/60—Processes or apparatus using other separation and/or other processing means using adsorption on solid adsorbents, e.g. by temperature-swing adsorption [TSA] at the hot or cold end
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • 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
  • F25J2215/52—Oxygen production with multiple purity O2
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2235/00—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams
  • F25J2235/52—Processes or apparatus involving steps for increasing the pressure or for conveying of liquid process streams the fluid being oxygen enriched compared to air ("crude oxygen")
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • 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
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S62/00—Refrigeration
  • Y10S62/923—Inert gas
  • Y10S62/925—Xenon or krypton

Definitions

• the invention relates to a method for low-temperature air, in which compressed and pre-cleaned feed air is introduced into a rectification system for nitrogen-oxygen separation, which has a pressure column, at least part of the compressed and pre-cleaned feed air being fed to the pressure column and an oxygen-enriched one Fraction of the pressure column is removed and fed to another Anlagensch ⁇ tt within the rectification system
• the rectification system for nitrogen-oxygen separation can be a single column system with a single column, the pressure suction in the sense of Invention to deal with a two-column system with a pressure column and a low-pressure column or a multi-column system with further separation columns for nitrogen-oxygen separation
• Several examples of single column systems are shown in Hausen / Linde (page 282, picture 4 1 and 4 2, page 287, picture 4 4, pages 329/330, picture 4 30, 4 31 and 4 32), the invention is particularly applicable to a single column with head cooling by means of an oxygen-enriched liquid from the pressure column (Hausen / Linde, page 330, picture 4 31)
• two-column systems can be found in Hausen / Linde (page 284, picture 4 3 and various examples in sections 4 5 1 and 4 5 2) For the generation of ascending D Ampf for the low-pressure column
• the rectification system for nitrogen-oxygen separation in the sense of the invention also comprises heat exchangers such as condenser evaporators which are required for the operation of the separation column (s) for nitrogen-oxygen separation (In particular the main capacitor of a double column or the top capacitor of a single column)
• the method and the corresponding device according to the invention can, if necessary, have additional separation columns for the extraction of further air components, for example noble gases such as argon helium neon krypton or xenon, outside the rectification system for nitrogen-oxygen separation (see Hausen / Linde, Chapter 4 5 4)
• the oxygen-enriched fraction is usually removed from the sump area of the pressure column before it is fed to a further work step within the rectification system.
• This further work step can be formed, for example, by further separation in the low-pressure column of a double-column system or by evaporation, for example in the top condenser of a single-column system All heavier impurities in the feed air, which were not removed in the pre-cleaning upstream of the introduction into the rectification system, are further transported with the oxygen-enriched fraction in the subsequent work steps ("heavily contaminated contaminants" are components of the feed air whose boiling point is higher than that of oxygen )
• such less volatile impurities can accumulate further.
• Some of these less volatile substances, in particular N 2 O, can precipitate out as solids and must be removed from time to time so that the heat exchanger passage in the corresponding evaporators (for example in the main condenser of a double column system) is not blocked
• the entire plant must be switched off. In a large air separation plant, this can mean a shutdown of, for example, two to five days.
• the entire oxygen-enriched fraction (in the case of a double column, the bottom liquid of the pressure column) is passed in liquid form via an adsorber to remove N 2 0 (liquid adsorbers used to be used at the same point for acetylene removal) This procedure triggers the operational engineering
• the coil fraction drawn off in the bottom of the pressure column from the method in which it is discarded, possibly after recovery of part of its cold.
• the coil fraction can, for example, be in a liquid state can be discarded immediately after being discharged from the pressure column, for example into the atmosphere via an ejector Alternatively, it can be evaporated and / or warmed by indirect heat exchange with a heating medium and then discarded in the gaseous state.This recovers part of the energy contained in the coil fraction in the form of cold. The evaporation should take place at such a high temperature that a failure of more volatile
• Contamination is avoided, for example by introducing the liquid coil fraction into a residual gas fraction at medium temperature.
• Another possibility is to recover the cold in a heat exchanger with switchable passages (Revex) .All these methods can be useful in certain systems, but have the disadvantage that the Separation work performed on the winding fraction is lost and there is thus a high level of operational expenditure in the form of additional energy requirements
• the invention is therefore based on the object of designing a method of the type mentioned at the beginning and a corresponding device in such a way that the outlay in terms of operating technology can be kept particularly low in the entire process
• the winding fraction which is formed by at least part, preferably all, of the bottom liquid of the pressure column, is fed to a device for removing N 2 O without prior evaporation
• the purified coil fraction downstream of this device can be fed to further workstations inside or outside the rectification system for nitrogen-oxygen separation without there being any risk of N 2 0 accumulation in the course of this workstep.
• the further workstep can, for example, be a column for nitrogen-oxygen separation or have a condenser-evaporator for generating reflux for such a column, such as the low-pressure column of a two-column system for nitrogen-oxygen separation or the top condenser of the pressure column
• the mass transfer section between the point at which the feed air is supplied (usually at the bottom of the pressure column) and the removal of the oxygen-enriched fraction enables a largely complete washing out of the less volatile Contamination, in particular of N 2 0, from the feed air into the sump of the pressure column. It is formed either by at least one practical base or by a packing section with a separation effect from at least one theoretical base.
• the pressure column can be implemented as a single container. Alternatively, different sections can be enclosed by separate containers
• Mass transfer section which serves to wash out N 2 0, be constructed separately from the rest of the pressure column (see device according to claim 11)
• the oxygen-enriched fraction contains, for example, less than 1 ppb N 2 O (molar concentration less than 10 "9 ), preferably the molar N 2 O concentrate at 10 "12 or below
• the less volatile impurities such as N 2 0 are removed with the liquid coil fraction from the bottom of the pressure column.
• the coil fraction can be removed continuously or discontinuously.
• the amount of coil fraction withdrawn is determined by the desired or permitted concentration of less volatile components in the coil fraction. As a rule, it is determined set so that no solids failure occurs in the sump of the pressure column, but under certain circumstances a higher enrichment with solids failure is also possible mol% to 5 mol% of the input air volume (the Information about the amount of reel fraction should be understood as a temporal average of the amount of reel fraction - especially in the case of discontinuous removal.)
• N 2 0 is removed from the liquid rinsing fraction in the cleaning stage by physical adsorption.
• the cleaning stage is therefore formed by a liquid adsorber.
• This liquid adsorber can be made much more compact than the liquid adsorber previously used for acetylene removal, through which the entire oxygen-enriched fraction was passed.
• the N 2 0 can be precipitated in a specially provided heat exchanger by evaporating the liquid rinsing fraction in the cleaning stage by indirect heat exchange, with N 2 O being precipitated as a solid and / or liquid during evaporation. They can be deposited in the heat exchanger in which the evaporation is carried out. In this case, the evaporation must be carried out discontinuously or in a switchable pair of recuperative or regenerative heat exchangers, so that the deposited solids are removed at certain time intervals. However, it is also possible to continuously withdraw any liquid or solids and the cleaned rinsing fraction.
• Another possibility is to remove N 2 0 in the purification stage by countercurrent mass transfer from the rinsing fraction.
• the rinsing fraction in the liquid state is introduced into an additional separation column, for example at an intermediate point or on the head.
• the bottom fraction of the separation column is discarded, for example, while the top fraction is processed further, for example in the pressure column.
• Heat must be supplied to the bottom of the separation column, for example by indirect heat exchange with a hot current (transfer of sensible heat) or with a condensing gas stream of suitable composition by means of an electrically operated heater.
• head cooling is necessary, for example by indirect heat exchange with an evaporating process stream of suitable composition and suitable pressure
• the cleaning stage has both at least one adsorption bed and at least one switchable pair of heat exchangers
• the purified winding fraction can at least partially be fed to a working step outside of this rectification system.
• a system for the rectification of a noble gas for example krypton and / or Xenon
• a noble gas for example krypton and / or Xenon
• Examples of such systems can be found in the older German patent application 19823526 7 and in the corresponding applications by the same applicant, as well as in EP 96610 A, EP 222026 A, DE 1667639 A, DE 1122088 B or in Streich et al, extraction of noble gases in Air and ammonia systems, Linde reports from technology and science, 37/1975, 10-14
• the cleaned coil fraction is preferably at least partially introduced in a liquid state into an exchange column which is used to convert krypton and xenon into an inert gas (nitrogen or argon ) to embed this exchange pillar can also be used with the usual krypto ⁇ - and xenon-containing use, namely
• the total air that is to say the entire feed air which is broken down in the rectification system
• the entire feed air is preferably fed into the pressure column at least one theoretical or practical base below the point at which the oxygen-enriched fraction is drawn off It is thus avoided that a direct feed of air into further working sections within the rectification system (for example via an air turbine which leads into the low pressure column of a two column system) undesirable less volatile impurities get into an aerodynamic downstream of the pressure column
• process cold is generated by work-relieving relaxation of an intermediate fraction which is removed from the pressure column above the air feed.
• the removal point can be, for example, at the intermediate point at which the oxygen-enriched fraction is removed, at the top of the pressure column, or at each point arranged between these two points.
• the intermediate fraction is practically N 2 O-free and can therefore be fed to the low-pressure column after the work-relieving expansion
• a portion of the compressed and pre-cleaned air can be branched off upstream of the pressure column and expanded to perform the work, but the relaxed air must then not be fed to the pressure column above the air supply or to a working section of the rectification system downstream of the pressure column, but is, for example, added to a residual stream and removed from the process
• kite can be increased by increasing the pressure in the intermediate fraction.
• the intermediate fraction can be removed from the pressure column in gaseous form, heated and compressed in the gaseous state before the work-related relaxation, for example. It is advantageous to use at least part of the mechanical energy for this compression of work-relieving relaxation is obtained.
• the pressure after compression is, for example, 7 to 15 bar, preferably 8 to 12 bar. The amount of the pressure difference depends here, as in the following paragraph, on the cooling requirement of a specific system
• the intermediate fraction upstream of the work-relieving expansion is drawn off in the liquid state from the pressure column, subjected to a pressure increase in the liquid state, evaporated and heated by indirect heat exchange.
• the liquid pressure increase leads to a pressure of, for example, 7 to 15 bar, preferably 8 to 12 bar
• the method according to the invention is operated in connection with an internal compression process in which a product stream is brought to pressure in a liquid state (for example 7 to 50 bar, preferably 9 up to 30 bar) and then evaporated against a heating fluid under high pressure (e.g. 7 to 50 bar, preferably 9 to 30 bar), it is advisable to deviate from the usual procedure (the pressures depend in individual cases on the required product pressure) instead of one
• a heating fluid for example 7 to 50 bar, preferably 9 up to 30 bar
• a heating fluid under high pressure e.g. 7 to 50 bar, preferably 9 to 30 bar
• part of the bottom liquid of the pressure column can be evaporated and the gas formed in this way can be returned to the pressure column.
• This optional bottom heating of the pressure column is preferably effected by a condenser-evaporator, which is acted on with a suitable process gas as heating medium Turnover increased in the section of the pressure column that is below the removal of the oxygen-enriched fraction.Therefore, further substances, in particular krypton and / or methane, are washed into the sump of the pressure column. This effect is further enhanced if the pressure column in this case has a further mass transfer section which is arranged below the point at which the compressed and pre-cleaned feed air is introduced into the pressure column and has the scope of some theoretical ground
• the invention also relates to a device for the low-temperature decomposition of air according to claim 11 or 12
• the pressure column in the sense of the invention is then formed by the combination of this guard column with a main column.
• the feed air is led into the guard column.
• the rinsing fraction is drawn off in liquid form from the sump of the guard column.
• At the head of the guard column at least one theoretical or practical base above the air supply gas is drawn off and introduced into the lower area of the main column.
• the oxygenated fraction is then withdrawn from the bottom of the main column.
• the main column is part of the existing rectification system.
• the top gas from the guard column is introduced into the main column via the previous feed air line, and the oxygen-enriched fraction can be drawn off via the existing bottom liquid line.
• the retrofitting can therefore be accomplished by providing a guard column to retain contaminants such as N 2 O that are difficult to escape. This method can also be useful when building an air separation plant, for example if a particularly low construction height is desired.
• Figure 2 shows an embodiment of the invention with the extraction of krypton and / or xenon
• Figure 3 shows a variant with a different method for the extraction of
• Process cold and Figure 4 shows a process with the extraction of pressurized oxygen by means of internal compression.
• FIG. 1 shows a double column system for nitrogen-oxygen separation.
• Compressed feed air 1 is fed to pre-cleaning 2 and is preferably subjected to adsorption there. Water vapor and CO 2 are practically completely removed from the compressed feed air. In contrast, about 20 to 50% of N 2 0 is let through by a conventional molecular sieve.
• the pre-cleaned feed air 3 is in a main heat exchanger 4 in indirect heat exchange cooled against decomposition products and completely fed via line 5 to the pressure column 6 of the rectification system.
• the rectification system for nitrogen-oxygen separation also has a low-pressure column 7, which via a condenser-evaporator is the main condenser 8, with the pressure column 6 in heat exchange relationship at the head of the pressure column 6, pressure nitrogen 9 is generated, which is partially or completely fed to the main condenser 8 and is condensed there at least partially, preferably completely or essentially completely.
• a part 11 of the nitrogen 10 liquefied in the main condenser 8 is fed in as a return to the pressure column 6.
• At least part 12 of the remaining condensate is led to the upper area of a low-pressure column 7.
• Evaporating bottom liquid of the low-pressure column evaporates on the evaporation side of the main condenser 8.
• the steam generated rises in the low-pressure column in counterflow to the return flow liquid (the main con de ⁇ sator 8 is in the exemplary embodiment of the drawing directly in the sump of the low pressure column, alternatively it can be arranged outside the double column)
• An oxygen-enriched fraction 13 is taken in liquid form from the pressure column 6 and fed to the low-pressure column 7 at an intermediate point as a further use fraction (14)
• the oxygen-enriched fraction 13 is not drawn from the bottom of the pressure column, but from an intermediate point above a mass transfer section 15 is arranged, which corresponds to three theoretical plates in the example. It is therefore free of more volatile impurities such as xenon, C 2 H 4 , N 2 0 and C 3 H 8. Thus, no N 2 0 can get into and into the low-pressure column 7
• Malfunctions in the Hauptko ⁇ densator 8 lead
• the less volatile constituents are drawn off from the sump of the pressure column 6 with a liquid winding fraction 16 and fed in the liquid state to a cleaning stage 17 in which N 2 0 is removed.
• N 2 0 removal is effected by means of adsorption.
• the cleaned liquid winding fraction 18 is Together with the oxygen-enriched fraction 13, the low-pressure column 7 is fed in as an alternative. A separate feed is also possible a few floors below.
• the entire feed air is fed into the pressure column 6 via the line 5, in particular, no feed air enters the low-pressure column 7 without pre-disassembly (for example via a Turbine)
• the mass transfer section 15 below the removal of the oxygen-enriched fraction 13 can be formed by any known mass transfer element, for example by packing or any type of mass transfer tray, preferably sieve tray or bell and / or chimney tray with a very small amount of coil fraction
• the oxygen product is withdrawn in gaseous form from the low-pressure column 7 via line 21, warmed in the main heat exchanger 4 and discharged as a product via line 22.
• the withdrawal is arranged some theoretical or practical bottom above the sump of the low-pressure column in order to avoid more volatile components such as krypton and / or To keep xenon away from the oxygen product These more volatile components are withdrawn from the bottom liquid of the low-pressure column using a liquid product or winding stream 24.
• oxygen can be supplied as a krypton- and xenon-free liquid product via line 23 and / or as a gaseous product which still contains krypton and Xenon contains, can be removed via line 25 (the heating of the product to be drawn off via line 25 and the supercooling of the oxygen-enriched fraction 13 are not shown in the drawing)
• a nitrogen-containing fraction 19 is drawn off as a gaseous nitrogen product or residual gas above the head of the low-pressure column 7 and heated in the main heat exchanger 4.
• the heated nitrogen-containing fraction 20 can be used in part as a regeneration gas for the pre-cleaning 2
• the cold process is obtained in the exemplary embodiment by means of work-relieving expansion of an intermediate fraction 30, which is withdrawn from the pressure column 6 in the amount of the deduction of the oxygen-enriched fraction 13 or higher in gaseous form Compressed 5 bar to 7 bar and fed to the main heat exchanger 4 after cooling 33 (line 34).
• the compressed air is removed from the main heat exchanger at an intermediate temperature (line 35 and a relaxation machine 36 are fed in). Downstream of the work-relieving relaxation 36 to 1 2 bar it is via line 37 of the low pressure column 7 fed at an intermediate point.
• both the removal from the pressure column 6 and the feed into the low-pressure column 7 are located at those intermediate points at which the oxygen-rich fraction 13, 14 is also drawn off or introduced.
• At least a part of the energy required for the compression of the heated gas fraction 31 is formed by the mechanical energy generated during the relaxation 36;
• the expansion machine 36 and the compressor 32 are preferably coupled mechanically.
• the compression 32 can be omitted; then it is sufficient to warm the gas fraction 30 only up to a medium temperature and then to supply it directly via line 35 to the work relaxation 36.
• FIG. 2 shows a variant of the method according to FIG. 1, in which krypton and xenon are obtained in addition to oxygen and nitrogen.
• further process steps and devices for krypton / xenon extraction are provided, which are located outside the rectification system for nitrogen-oxygen separation.
• Oxygen fraction 24 which is drawn off from the bottom of the low-pressure column, serves as a common use for system 202 for krypton / xenon extraction.
• the cleaned rinsing fraction downstream of the cleaning stage 17 is partly or completely fed via line 201 to the system 202 for krypton / xenon extraction, preferably in the liquid state. It can in particular be fed at a suitable point into an exchange column which is used to produce a krypton- and xenone-containing but oxygen-free mixture, or into another column for the pre-enrichment of krypton and / or xenon. The feed point is below the head of the corresponding column.
• an intermediate fraction 340 in the amount of the withdrawal of the oxygen-enriched fraction 13 or higher in liquid form is removed from the pressure column 6. It is brought to an increased pressure of, for example, 7 bar in liquid form by a pump 341 and then via line 342 to the Main heat exchanger 4 supplied. There it is evaporated under the increased pressure and warmed to an intermediate temperature.
• the warmed intermediate fraction will Via line 335 fed to a relaxation machine 336 Downstream of the work-relieving relaxation 336, it is fed via line 337 to the low-pressure column 7 at an intermediate point or discharged as a product
• Intermediate fraction 342 is a heating medium, which is taken out in gaseous form via line 330 from an intermediate point (alternatively from the head) of the pressure column 6 and heated in the main heat exchanger 4.
• the heated heating medium 331 is compressed in a compressor 332, for example, to 8 bar and, after cooling 333, is returned to the main heat exchanger 4 fed (line 334) There it is cooled and finally at least partially condensed.
• the condensed heating medium 343 is expanded back into the pressure column, preferably at the point of its removal via line 330 or somewhat higher
• At least a part of the energy required for the compression of the heated heating means 331 is generated by the mechanical energy generated during the work-relieving expansion 336, preferably the expansion machine 336 and the compressor 332 are mechanically coupled for this purpose
• the tapping points of the intermediate fraction to be relaxed for work and the heating medium are at the same level, namely at that of the deduction of the oxygen-enriched fraction 13. They could also be at different levels, for example it is possible for both to be at different points above the Removal of the oxygen-enriched fraction 13 to be arranged. This also shifts the feed point in the low-pressure column and the pressure column
• the process shown schematically in FIG. 4 serves to obtain gaseous oxygen under increased pressure by internal compression.
• liquid oxygen 423 from the low-pressure column 7 is brought to an increased pressure of, for example, 9 bar in a pump 452.
• the liquid 453 is brought to the main heat exchanger under the high pressure 4 fed and evaporated and heated there via line 422, the gaseous printed product is withdrawn
• An intermediate fraction serves as heating fluid for the evaporation of the liquid oxygen 453, which is taken out in gaseous form via line 430 from an intermediate point (alternatively from the head) of the pressure column 6 and is heated in the main heat exchanger 4 20 bar compressed and after
• After-cooling 433 is again fed to the main heat exchanger 4 (line 454), where it is cooled and at least partially condensed.
• the condensed heating fluid 455 is throttled back into the pressure column, preferably at the point of its removal via line 430 or somewhat higher part 434 of those compressed in the compressor 432 Intermediate fraction 430/431 from the pressure column can be used for the
• Cold production can be used by removing it from the main heat exchanger at an intermediate temperature (line 35) and feeding it to a decompression machine 36.
• the fraction that is relaxed for work is fed via line 37 downstream of the work-related expansion 36 to the low-pressure column 7 at an intermediate point.
• it can be pricked Line 451 shown are returned to the pressure column 6
• FIGS. 3 and 4 can be combined with the crypto / xenon extraction according to FIG. 2

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• General Engineering & Computer Science (AREA)
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• 1998
  • 1998-11-11 DE DE19852020A patent/DE19852020A1/de not_active Withdrawn
  • 1998-12-11 EP EP98123463A patent/EP0978699A1/fr not_active Withdrawn
• 1999
  • 1999-08-04 TW TW088113317A patent/TW429301B/zh not_active IP Right Cessation
  • 1999-08-05 AU AU53737/99A patent/AU5373799A/en not_active Abandoned
  • 1999-08-05 EP EP99939452A patent/EP1102954B1/fr not_active Expired - Lifetime
  • 1999-08-05 ES ES99939452T patent/ES2188211T3/es not_active Expired - Lifetime
  • 1999-08-05 WO PCT/EP1999/005678 patent/WO2000008399A1/fr active IP Right Grant
  • 1999-08-05 US US09/762,196 patent/US6418753B1/en not_active Expired - Fee Related
  • 1999-08-05 CN CNB998094021A patent/CN1171065C/zh not_active Expired - Fee Related
  • 1999-08-05 AT AT99939452T patent/ATE228637T1/de not_active IP Right Cessation
  • 1999-08-05 DE DE59903564T patent/DE59903564D1/de not_active Expired - Fee Related

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