WO2023198307A1 - Process and apparatus for producing argon from crude argon - Google Patents

Process and apparatus for producing argon from crude argon Download PDF

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Publication number
WO2023198307A1
WO2023198307A1 PCT/EP2023/025114 EP2023025114W WO2023198307A1 WO 2023198307 A1 WO2023198307 A1 WO 2023198307A1 EP 2023025114 W EP2023025114 W EP 2023025114W WO 2023198307 A1 WO2023198307 A1 WO 2023198307A1
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Prior art keywords
stream
argon
separation stage
oxygen
crude argon
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PCT/EP2023/025114
Other languages
French (fr)
Inventor
Matthias Grahl
Dirk Schwenk
Georg KAMML
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Linde Gmbh
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Publication date
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Publication of WO2023198307A1 publication Critical patent/WO2023198307A1/en

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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
    • F25J3/04866—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
    • 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
    • F25J3/04648—Recovering noble gases from air argon
    • F25J3/04654—Producing crude argon in a crude argon column
    • F25J3/04666—Producing crude argon in a crude argon column as a parallel working rectification column of the low pressure column in a dual pressure main column system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • 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
    • F25J3/04648—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
    • 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
    • F25J3/04648—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
    • F25J3/04715—The auxiliary column system simultaneously produces 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
    • F25J3/04642—Recovering noble gases from air
    • F25J3/04648—Recovering noble gases from air argon
    • F25J3/04721—Producing pure argon, e.g. recovered from a crude argon column
    • F25J3/04733—Producing pure argon, e.g. recovered from a crude argon column using a hybrid system, e.g. using adsorption, permeation or catalytic reaction
    • F25J3/04739—Producing pure argon, e.g. recovered from a crude argon column using a hybrid system, e.g. using adsorption, permeation or catalytic reaction in combination with an auxiliary pure argon 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
    • 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
    • F25J2205/64—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 by pressure-swing adsorption [PSA] at the hot end
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/80—Processes or apparatus using other separation and/or other processing means using membrane, i.e. including a permeation step
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
    • F25J2205/00—Processes or apparatus using other separation and/or other processing means
    • F25J2205/82—Processes or apparatus using other separation and/or other processing means using a reactor with combustion or catalytic reaction
    • 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
    • F25J2230/00—Processes or apparatus involving steps for increasing the pressure of gaseous process streams
    • F25J2230/58—Processes or apparatus involving steps for increasing the pressure of gaseous 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
    • F25J2245/58—Processes or apparatus involving steps for recycling of process streams the recycled stream being argon or crude argon

Definitions

  • This invention regards to a process for producing argon by further separating a crude argon product and to a respective apparatus according to the introductory parts of the independent claims.
  • Such process and apparatus is particularly used for further separating a crude argon product from an argon rejection column and retrofitting a respective plant for producing a pure argon product.
  • the "distillation system for oxygen-nitrogen separation" of the invention can be a classical Linde double column.
  • Other systems e.g. with two or more columns side by side or three- or more-column system may be used.
  • Cryogenic air separation plants have nitrogen and/or oxygen as their main product. If an argon-free oxygen product, but no pure argon product is desired, a relatively short argon rejection column is used. It works similarly as a crude argon column of conventional argon production units, but is much smaller.
  • a crude argon product containing 70 to 95 mol%, preferably 79 to 91 mol%, e.g. 80 mol% argon, and 5 mol% to 30 mol% oxygen and 1 mol% to 8 mol% nitrogen. The crude argon is warmed in the main heat exchanger to about ambient temperature and then normally rejected.
  • Such plant for producing warm crude argon is denominated as “main unit” here. As it works under cryogenic temperatures, it must be insulated. It has a “first coldbox set” consisting of one or more coldboxes. The cold parts of the main unit are arranged in the interior of such coldbox or such coldboxes.
  • the term "coldbox set” generally means either a single coldbox or an arrangement of two or more coldboxes.
  • a coldbox may generally be filled with insulation material like perlite or vacuum insulated.
  • Another solution could be a purely cryogenic approach rebuilding the main plant to a classical argon plant. That would mean, however, introducing additional trays or additional packing into the low-pressure column of the existing plant and adding a full argon production with crude and pure argon columns. Such approach would not only mean huge apparatus effort, but the existing plant would suffer from a long-term shutdown.
  • the invention does not need cold crude argon taken out of an insulated part of the plant to be retrofit by the process and apparatus of the invention, but is uses warm crude argon product as it comes from the warm end of the main heat exchanger.
  • "Warm" means in this application a temperature above 270 K. That minimizes the effect of the retrofitting on the original plant.
  • a tie in for a waste argon product valve has to be installed between main heat exchanger of the existing plant and waste argon control valve.
  • the main plant does not need to be shut down for a considerable time and the apparatus effort is relatively low.
  • the original coldbox is not modified.
  • the oxygen content may be 10 to 30 mol%, preferably 15 to 20 mol%
  • the nitrogen content may be 1 to 8 mol%, preferably 1 .1 to 2.9 mol%, and converts that into a final valuable pure argon product being oxygen-free and nitrogen-free, meaning having an oxygen content of less than 3 ppm, preferably less than 1 ppm and a nitrogen content of less than 3 ppm, preferably less than 1 ppm.
  • the crude argon feed is taken from the warm end of the main heat exchanger of an existing air separation stage with dummy argon system, at a pressure of 1 .1 to 1 .5 bara and about ambient temperature. It is first pressurized in a compressor to a higher pressure of 3.5 to 9.5 bara and then fed to a first separation stage.
  • the first separation stage is a PSA unit, in particular a conventional pressure swing adsorption unit for reducing oxygen content, comprising a pair of adsorption vessels 4 filled with a carbon molecular sieve. It is operated by a standard PSA process.
  • the final pure argon product from the lower portion of the distillation column is preferably recovered as a liquid stream from the lower portion, in particular from the bottom of the pure argon column.
  • the liquid pure argon may be stored in a storage tank or transported in liquid form.
  • At least a portion of the final pure argon product from the lower portion of the distillation column may be recovered as a gaseous stream.
  • the gas may be warmed, e.g. in the heat exchanger.
  • the gaseous warm crude argon stream (1 ) is pressurized in a compressor (2) upstream the first separation stage (101 ).
  • the gaseous warm crude argon stream may be pressurized in a compressor upstream the first separation stage. Such pressure should be sufficient to drive the first separation stage - or even all three separation stages
  • the distillation column of the second separation stage may have a bottom reboiler, preferably being a condenser-evaporator.
  • the oxygen-free argon stream from the second separation stage is at least partially liquefied in a bottom reboiler of the distillation column, in particular in the liquefaction space of the reboiler, and the liquefied portion from the bottom reboiler is sent into the distillation column at an intermediate height.
  • the argon recovery may be further improved by a recycling step.
  • the argon-depleted first waste stream from the first separation stage is eventually recompressed and introduced into a fourth separation stage.
  • An argon-enriched effluent stream is withdrawn from the fourth separation stage and then mixed with the crude argon stream upstream first separation stage. If there is a compressor upstream the first separation stage, the mixing may be performed upstream or downstream of such compressor or at an intermediate stage of such compressor.
  • the argon concentration in the first waste stream is increased from 65 to 75 mol%, e.g. about 70 mol% to a higher argon content of 70 to 90 mol%, e.g. about 80 mol%.
  • the argon recovery from the crude argon stream can be increased from 50 to 60 % to 75 to 90 %.
  • Such fourth separation stage preferably comprises a further pressure swing adsorption unit and/or a membrane separation stage for separating argon and oxygen.
  • no stream from the purification unit is introduced into the first coldbox set of the main unit.
  • the single fluid flow between the first set of coldboxes and the second set of coldboxes is the warm crude argon stream.
  • a refrigeration agent is need, preferably liquid nitrogen. That may be taken from a source outside the main plant. In some cases, it is advantageous to take it from the main unit or from a tank filled from the main unit. In such case, the warm crude argon stream and a liquid nitrogen stream would be the only fluid flows between the first set of coldboxes and the second set of coldboxes.
  • the invention additionally concerns an apparatus according to claim 13. Further preferred variants of the invention comprise such apparatus plus one or more of the features of claims 2 to 8 converted to apparatus features. Also part of the invention is a process for manufacturing an air separation plant by retrofitting. During such retrofitting, an apparatus according to claim 13 is added to an existing cryogenic air separation in order to supplement an argon production.
  • FIG 1 shows an embodiment of the "main unit” according to the invention.
  • FIG. 2 depicts an embodiment of the "purification unit" according to the invention.
  • Figure 1 shows in a simplified manner the main unit 200 being a cryogenic air separation stage for nitrogen-oxygen separation additionally producing a crude argon stream.
  • main unit 200 atmospheric air is compressed in a main air compressor 202 after being filtered in filter 101 for being used as feed air in main unit 200.
  • the feed air is then cooled in a precooling system 203 and purified in a prepurification system 204.
  • the purified feed air is then cooled in a main heat exchanger 205 in one or more streams. Parts of the feed air may be further compressed and or turbine or throttle expanded. Those details are not shown in the drawing, but roughly symbolized by the three dots.
  • the cooled air 206 is introduced to the distillation system of the main unit.
  • the main unit of the embodiment has a double column 210 consisting of a high- pressure column 211 , a low-pressure column 212 and a main condenser 213. Additionally, there is an argon rejection column 214 being connected to the double column as usual for crude argon columns and having a top condenser 215.
  • At least a portion of the cooled air 206 is fed into the high-pressure column 211 .
  • the high-pressure column 211 and the low-pressure column 212 are connected in the usual manner, e.g. by transferring a portion of an oxygen-enriched stream 207 taken from the high-pressure column into the low-pressure column. Another portion of the stream 207 is fed to the top condenser 215 of the argon rejection column 214 as a cooling medium.
  • an argon-rich transfer fraction 208 is withdrawn and introduced into the argon rejection column 214; an argon- depleted liquid 209 is returned to the low-pressure column 212.
  • the crude argon stream 220 is warmed in the main heat exchanger 205 to about ambient temperature, in particular to 250 to 230 K, specifically to 260 to 320 K.
  • the main unit has a thermal insulation comprising a first coldbox set consisting of a single first coldbox 221 containing the cold parts of the main unit.
  • Figure 2 does not comprise the "original plant” or "main plant” comprising a dummy argon column.
  • the product of such dummy argon column (argon rejection column), after warming in the main heat exchanger of the main plant, constitutes the feed gas to the process of the invention, i.e. crude argon 1 having, in this particular example, approximately 17 mol% oxygen and approximately 3 mol% nitrogen content.
  • crude argon 1 having, in this particular example, approximately 17 mol% oxygen and approximately 3 mol% nitrogen content.
  • approximately 3000 Nm 3 /h crude argon are taken from warm end of main heat exchanger of the existing mega ASU having a dummy argon system.
  • the crude argon stream 1 is first pressurized in a compressor 2 with aftercooler 3 to a higher pressure of 3.5 to 9.5 bara. and then fed to a first separation stage 101 .
  • the first separation stage 101 is a PSA unit, in particular a conventional pressure swing adsorption unit for reducing oxygen content comprising a periodically operated pair of adsorption vessels 4 filled with a carbon molecular sieve. It is operated by a standard PSA process.
  • the oxygen-depleted argon stream 5 withdrawn as product from the first separation stage 101 has an oxygen content of 0.1 to 2.0 mol% and a pressure of 3 to 9 bara.
  • an argon-depleted first waste stream 6 is withdrawn from the first separation stage a released to the atmosphere (ATM).
  • the argon-depleted first waste stream 6 or a portion thereof is eventually recompressed (not shown in the drawing and introduced via line 104 into a fourth separation stage 105.
  • An argon-enriched effluent stream 106 is withdrawn from the fourth separation stage and then mixed with the crude argon stream upstream first separation stage, the mixing may be performed upstream or downstream of such compressor or at an intermediate stage of such compressor.
  • the argon concentration in the first waste stream is increased from 65 to 75 mol%, e.g. about 70 mol% to a higher argon content of 70 to 90 mol%, e.g. about 80 mol%.
  • the argon recovery from the crude argon stream can be increased from 50 to 60 % to 75 to 90 %.
  • oxygen-depleted argon stream 5, 7, possibly mixed with one or more return streams is further compressed in a compressor 8 with aftercooler 9 to a pressure of 4 to 10 bara, preferably to 5.5 to 6 bara.
  • Compressor 8 and aftercooler 9 are optional.
  • the PSA unit 101 may be operated under further elevated pressure, being sufficient to press the oxygen-depleted argon stream 5, 7 through the second purification unit 102.
  • Hydrogen 21 is added to the (eventually) compressed oxygen-depleted argon stream
  • the hot effluent 13 is now oxygen free, i.e. it contains less than 3 ppm oxygen. It is cooled down in an atmospheric cooler 14 and a following water cooler 15 to about ambient temperature.
  • Phase separator 17 serves for removing liquid water (water removal line not shown in the drawing) from the oxygen-free but water containing stream 16. From such phase separator optionally a recycling stream 20 may be removed and admixed to the oxygen-depleted stream 5 upstream the compressor 8, in particular for temperature control of the reactor 12.
  • the oxygen-free mixture 18 is then sent to an adsorptive drier 19 for removal of water vapour.
  • drier 19 may be of conventional type, using e.g. alumina as adsorbent.
  • the pair of adsorbers is periodically regenerated by a waste stream 22, preferable consisting of pure nitrogen from the third separation stage 103, the main plant (not depicted here) or another air separation stage.
  • Dry oxygen-free argon 24 (eventually cooled in water cooler 23) is then sent the third separation stage 103. There it is cooled by indirect heat exchange in a heat exchanger 25 and at partially liquified in bottom reboiler 26.
  • the liquid produced 27 produced in the liquefaction space of the bottom reboiler is introduced into a distillation column 28 at an intermediate level. To remove the remaining nitrogen, a very small column is sufficient for removing remaining nitrogen, operating like a conventional pure argon column, but having different types of top cooling and bottom reboiling.
  • the bottom reboiler is operated by the feed stream to column, i.e. the oxygen-free argon stream 24 from the second separation stage.
  • the top condenser 20 for the distillation column 29.
  • a cryogenic external liquid may be used, e.g. liquid nitrogen (LIN) from a tank or from the main unit or from another air separation stage.
  • non-condensable gases 31 mainly hydrogen
  • 32 mainly nitrogen
  • the final pure argon product 35 is withdrawn in liquid form from the bottom of the distillation column 28, meaning from the liquefaction space of the bottom reboiler 26.
  • the pure argon product or a portion of it is withdrawn in gaseous form via line 36 from the bottom of the distillation column 28, warmed up in heat exchanger 25 and recovered (GAR).
  • the purification unit 100 has a thermal insulation comprising a second coldbox set consisting of a single second coldbox 37 enclosing the cold parts of the purification unit 100, the single second coldbox being different from the single first coldbox of the first coldbox set.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Separation By Low-Temperature Treatments (AREA)

Abstract

The invention concerns a process for producing argon from crude argon and a respective apparatus. In the process, a gaseous warm crude argon stream (1) from a main unit is introduced into purification unit having a first separation stage (101) comprising a pressure swing adsorption unit (4), a consecutive separation stage (102) for further removing oxygen by catalytic combustion (12) with hydrogen (21) and a third separation stage (103) comprising a heat exchanger (25) and a distillation column (28). A final pure argon product (35/36) is withdrawn from the lower portion of the distillation column (28). Additionally, a purification unit and a process for retrofitting an existing air separation plant are claimed.

Description

Description
Process and Apparatus for Producing Argon from Crude Argon
This invention regards to a process for producing argon by further separating a crude argon product and to a respective apparatus according to the introductory parts of the independent claims. Such process and apparatus is particularly used for further separating a crude argon product from an argon rejection column and retrofitting a respective plant for producing a pure argon product.
The "distillation system for oxygen-nitrogen separation" of the invention can be a classical Linde double column. Other systems, e.g. with two or more columns side by side or three- or more-column system may be used.
Cryogenic air separation plants have nitrogen and/or oxygen as their main product. If an argon-free oxygen product, but no pure argon product is desired, a relatively short argon rejection column is used. It works similarly as a crude argon column of conventional argon production units, but is much smaller. At the top of the argon rejection column, a crude argon product containing 70 to 95 mol%, preferably 79 to 91 mol%, e.g. 80 mol% argon, and 5 mol% to 30 mol% oxygen and 1 mol% to 8 mol% nitrogen. The crude argon is warmed in the main heat exchanger to about ambient temperature and then normally rejected.
Such plant for producing warm crude argon is denominated as "main unit" here. As it works under cryogenic temperatures, it must be insulated. It has a "first coldbox set" consisting of one or more coldboxes. The cold parts of the main unit are arranged in the interior of such coldbox or such coldboxes. The term "coldbox set" generally means either a single coldbox or an arrangement of two or more coldboxes. A coldbox may generally be filled with insulation material like perlite or vacuum insulated.
As the demand for pure argon recently raised considerably, there is a need for retrofitting such plants in order to avoid rejection of the crude argon product and to convert the crude argon product to a valuable pure argon product. There is already a solution for that situation described in EP 2986924 B1 proposing equipping the argon- rejection plant with special connections prepared for the later retrofit. If, however, such preparation has not been done during the construction of the original plant, this method for retrofitting cannot be applied.
Another solution could be a purely cryogenic approach rebuilding the main plant to a classical argon plant. That would mean, however, introducing additional trays or additional packing into the low-pressure column of the existing plant and adding a full argon production with crude and pure argon columns. Such approach would not only mean huge apparatus effort, but the existing plant would suffer from a long-term shutdown.
It is the object of the invention to allow retrofitting a non-prepared argon-rejection plant for producing pure argon from crude argon, thereby being efficient in terms of energy and investment and minimizing the downtime of the plant during retrofitting.
Such technical problem is solved by the features of the independent claims.
The invention does not need cold crude argon taken out of an insulated part of the plant to be retrofit by the process and apparatus of the invention, but is uses warm crude argon product as it comes from the warm end of the main heat exchanger. "Warm" means in this application a temperature above 270 K. That minimizes the effect of the retrofitting on the original plant. Possibly, during the retrofit, a tie in for a waste argon product valve has to be installed between main heat exchanger of the existing plant and waste argon control valve. The main plant does not need to be shut down for a considerable time and the apparatus effort is relatively low. The original coldbox is not modified.
It works e.g. with a composition of the crude argon having at least 3 mol% oxygen and at least 1 mol% nitrogen, the remainder being nearly exclusively argon. The oxygen content may be 10 to 30 mol%, preferably 15 to 20 mol%, the nitrogen content may be 1 to 8 mol%, preferably 1 .1 to 2.9 mol%, and converts that into a final valuable pure argon product being oxygen-free and nitrogen-free, meaning having an oxygen content of less than 3 ppm, preferably less than 1 ppm and a nitrogen content of less than 3 ppm, preferably less than 1 ppm. In the process of the invention, the crude argon feed is taken from the warm end of the main heat exchanger of an existing air separation stage with dummy argon system, at a pressure of 1 .1 to 1 .5 bara and about ambient temperature. It is first pressurized in a compressor to a higher pressure of 3.5 to 9.5 bara and then fed to a first separation stage. The first separation stage is a PSA unit, in particular a conventional pressure swing adsorption unit for reducing oxygen content, comprising a pair of adsorption vessels 4 filled with a carbon molecular sieve. It is operated by a standard PSA process.
The final pure argon product from the lower portion of the distillation column is preferably recovered as a liquid stream from the lower portion, in particular from the bottom of the pure argon column. The liquid pure argon may be stored in a storage tank or transported in liquid form.
Alternatively or additionally, at least a portion of the final pure argon product from the lower portion of the distillation column may be recovered as a gaseous stream. The gas may be warmed, e.g. in the heat exchanger.
The gaseous warm crude argon stream (1 ) is pressurized in a compressor (2) upstream the first separation stage (101 ).
The gaseous warm crude argon stream may be pressurized in a compressor upstream the first separation stage. Such pressure should be sufficient to drive the first separation stage - or even all three separation stages
The distillation column of the second separation stage may have a bottom reboiler, preferably being a condenser-evaporator. In a preferred embodiment of the invention, the oxygen-free argon stream from the second separation stage is at least partially liquefied in a bottom reboiler of the distillation column, in particular in the liquefaction space of the reboiler, and the liquefied portion from the bottom reboiler is sent into the distillation column at an intermediate height.
In a further developed embodiment of the invention, the argon recovery may be further improved by a recycling step. In this variant, the argon-depleted first waste stream from the first separation stage is eventually recompressed and introduced into a fourth separation stage. An argon-enriched effluent stream is withdrawn from the fourth separation stage and then mixed with the crude argon stream upstream first separation stage. If there is a compressor upstream the first separation stage, the mixing may be performed upstream or downstream of such compressor or at an intermediate stage of such compressor. In the fourth separation stage, the argon concentration in the first waste stream is increased from 65 to 75 mol%, e.g. about 70 mol% to a higher argon content of 70 to 90 mol%, e.g. about 80 mol%. By such measure, the argon recovery from the crude argon stream can be increased from 50 to 60 % to 75 to 90 %.
Such fourth separation stage preferably comprises a further pressure swing adsorption unit and/or a membrane separation stage for separating argon and oxygen.
In the course of the invention, it is possible to erect the purification unit beside a running air separation plant (main unit) without any need to interrupt the operation of the main unit during such erection. For such purpose, the following features are preferred:
In a preferred embodiment, no stream from the purification unit is introduced into the first coldbox set of the main unit.
In the best case, the single fluid flow between the first set of coldboxes and the second set of coldboxes is the warm crude argon stream.
For operating the distillation column of the third separation stage, a refrigeration agent is need, preferably liquid nitrogen. That may be taken from a source outside the main plant. In some cases, it is advantageous to take it from the main unit or from a tank filled from the main unit. In such case, the warm crude argon stream and a liquid nitrogen stream would be the only fluid flows between the first set of coldboxes and the second set of coldboxes.
The invention additionally concerns an apparatus according to claim 13. Further preferred variants of the invention comprise such apparatus plus one or more of the features of claims 2 to 8 converted to apparatus features. Also part of the invention is a process for manufacturing an air separation plant by retrofitting. During such retrofitting, an apparatus according to claim 13 is added to an existing cryogenic air separation in order to supplement an argon production.
The invention as well as further details of the invention are described in the following by means of an exemplary embodiment, which is schematically shown in the drawings.
Figure 1 shows an embodiment of the "main unit" according to the invention.
Figure 2 depicts an embodiment of the "purification unit" according to the invention.
Figure 1 shows in a simplified manner the main unit 200 being a cryogenic air separation stage for nitrogen-oxygen separation additionally producing a crude argon stream.
For further explaining the main unit 200, we refer to the general technical literature, e.g. to H.-W. Haring, Industrial Gases Processing, Wiley-VCH, 2008, in particular chapter 2. It particularly indicated that Figure 1 , for clarity, does not show numerous streams apparatus parts which are present in the main unit 200. Only those which are important to explain the invention are shown and described.
In main unit 200, atmospheric air is compressed in a main air compressor 202 after being filtered in filter 101 for being used as feed air in main unit 200. The feed air is then cooled in a precooling system 203 and purified in a prepurification system 204. The purified feed air is then cooled in a main heat exchanger 205 in one or more streams. Parts of the feed air may be further compressed and or turbine or throttle expanded. Those details are not shown in the drawing, but roughly symbolized by the three dots. The cooled air 206 is introduced to the distillation system of the main unit.
The main unit of the embodiment has a double column 210 consisting of a high- pressure column 211 , a low-pressure column 212 and a main condenser 213. Additionally, there is an argon rejection column 214 being connected to the double column as usual for crude argon columns and having a top condenser 215.
At least a portion of the cooled air 206 is fed into the high-pressure column 211 . The high-pressure column 211 and the low-pressure column 212 are connected in the usual manner, e.g. by transferring a portion of an oxygen-enriched stream 207 taken from the high-pressure column into the low-pressure column. Another portion of the stream 207 is fed to the top condenser 215 of the argon rejection column 214 as a cooling medium.
From an intermediate height of the low-pressure column 212, an argon-rich transfer fraction 208 is withdrawn and introduced into the argon rejection column 214; an argon- depleted liquid 209 is returned to the low-pressure column 212. A crude argon stream 220 produced in the argon rejection column 214, warmed in the main heat exchanger 205 to produce a gaseous warm crude argon stream (1 ) containing oxygen and nitrogen and withdrawn via a crude argon production line. The crude argon stream 220 is warmed in the main heat exchanger 205 to about ambient temperature, in particular to 250 to 230 K, specifically to 260 to 320 K.
The main unit has a thermal insulation comprising a first coldbox set consisting of a single first coldbox 221 containing the cold parts of the main unit.
Figure 2 does not comprise the "original plant" or "main plant" comprising a dummy argon column. The product of such dummy argon column (argon rejection column), after warming in the main heat exchanger of the main plant, constitutes the feed gas to the process of the invention, i.e. crude argon 1 having, in this particular example, approximately 17 mol% oxygen and approximately 3 mol% nitrogen content. In the example, approximately 3000 Nm3/h crude argon (typically at 1 .2 bara and 283 K) are taken from warm end of main heat exchanger of the existing mega ASU having a dummy argon system.
The crude argon stream 1 is first pressurized in a compressor 2 with aftercooler 3 to a higher pressure of 3.5 to 9.5 bara. and then fed to a first separation stage 101 . The first separation stage 101 is a PSA unit, in particular a conventional pressure swing adsorption unit for reducing oxygen content comprising a periodically operated pair of adsorption vessels 4 filled with a carbon molecular sieve. It is operated by a standard PSA process.
The oxygen-depleted argon stream 5 withdrawn as product from the first separation stage 101 has an oxygen content of 0.1 to 2.0 mol% and a pressure of 3 to 9 bara. During regeneration, an argon-depleted first waste stream 6 is withdrawn from the first separation stage a released to the atmosphere (ATM).
Alternatively, the argon-depleted first waste stream 6 or a portion thereof is eventually recompressed (not shown in the drawing and introduced via line 104 into a fourth separation stage 105. An argon-enriched effluent stream 106 is withdrawn from the fourth separation stage and then mixed with the crude argon stream upstream first separation stage, the mixing may be performed upstream or downstream of such compressor or at an intermediate stage of such compressor. In the fourth separation stage, the argon concentration in the first waste stream is increased from 65 to 75 mol%, e.g. about 70 mol% to a higher argon content of 70 to 90 mol%, e.g. about 80 mol%. By such measure, the argon recovery from the crude argon stream can be increased from 50 to 60 % to 75 to 90 %.
In the second purification unit 102, oxygen-depleted argon stream 5, 7, possibly mixed with one or more return streams, is further compressed in a compressor 8 with aftercooler 9 to a pressure of 4 to 10 bara, preferably to 5.5 to 6 bara. Compressor 8 and aftercooler 9 are optional. Alternatively, the PSA unit 101 may be operated under further elevated pressure, being sufficient to press the oxygen-depleted argon stream 5, 7 through the second purification unit 102.
Hydrogen 21 is added to the (eventually) compressed oxygen-depleted argon stream
10 in order to remove oxygen in a catalytic reactor 12, the upstream phase separator
11 being optional. The hot effluent 13 is now oxygen free, i.e. it contains less than 3 ppm oxygen. It is cooled down in an atmospheric cooler 14 and a following water cooler 15 to about ambient temperature. Phase separator 17 serves for removing liquid water (water removal line not shown in the drawing) from the oxygen-free but water containing stream 16. From such phase separator optionally a recycling stream 20 may be removed and admixed to the oxygen-depleted stream 5 upstream the compressor 8, in particular for temperature control of the reactor 12.
The oxygen-free mixture 18 is then sent to an adsorptive drier 19 for removal of water vapour. Such drier 19 may be of conventional type, using e.g. alumina as adsorbent. The pair of adsorbers is periodically regenerated by a waste stream 22, preferable consisting of pure nitrogen from the third separation stage 103, the main plant (not depicted here) or another air separation stage.
Dry oxygen-free argon 24 (eventually cooled in water cooler 23) is then sent the third separation stage 103. There it is cooled by indirect heat exchange in a heat exchanger 25 and at partially liquified in bottom reboiler 26. The liquid produced 27 produced in the liquefaction space of the bottom reboiler is introduced into a distillation column 28 at an intermediate level. To remove the remaining nitrogen, a very small column is sufficient for removing remaining nitrogen, operating like a conventional pure argon column, but having different types of top cooling and bottom reboiling.
As already mentioned, the bottom reboiler is operated by the feed stream to column, i.e. the oxygen-free argon stream 24 from the second separation stage. There is also a top condenser 20 for the distillation column 29. As the cooling medium 30, a cryogenic external liquid may be used, e.g. liquid nitrogen (LIN) from a tank or from the main unit or from another air separation stage.
From the top condenser and the bottom reboiler non-condensable gases 31 (mainly hydrogen) and 32 (mainly nitrogen) are removed. Those gases and gaseous nitrogen
33 from the evaporation side of the top condenser 29 are warmed in the heat exchanger 23 and either rejected or used for a valuable purpose. In the drawing, line
34 serves for recycling the gas 31 from the bottom reboiler 26 is recycled into the oxygen-depleted argon stream 101 from the first separation step 101. Such recycling reduces the hydrogen demand.
The final pure argon product 35 is withdrawn in liquid form from the bottom of the distillation column 28, meaning from the liquefaction space of the bottom reboiler 26. Alternatively or additionally the pure argon product or a portion of it is withdrawn in gaseous form via line 36 from the bottom of the distillation column 28, warmed up in heat exchanger 25 and recovered (GAR).
All the waste streams (e.g. "Waste", "GAN", "ATM") from the purification unit are rejected. There is no process stream from the purification unit returned to the main unit, in particular not into the first set of colboxes 221 . In particular cases, the GAN stream can be mixed with a warm GAN product from the main unit 200. The purification unit 100 has a thermal insulation comprising a second coldbox set consisting of a single second coldbox 37 enclosing the cold parts of the purification unit 100, the single second coldbox being different from the single first coldbox of the first coldbox set.

Claims

Patent Claims Process for producing argon using
- a main unit (200) for producing crude argon from feed air and
- a purification unit (100) for purifying crude argon and producing argon,
- the main unit (200) having a thermal insulation consisting of a first coldbox set
(221 ),
- the purification unit (100) having a thermal insulation consisting of second coldbox set (37), all coldboxes of the second coldbox set being different from the coldboxes (221) of the first coldbox set,
- in the main unit (200)
- cooling feed air in a main heat exchanger (205),
- producing a crude argon stream (220) using cryogenic distillation and
- warming the crude argon stream (220) in the main heat exchanger (205) to produce a gaseous warm crude argon stream (1) containing oxygen and nitrogen and withdrawing it via a crude argon production line and
- sending the gaseous warm crude argon stream (1 ) from the main unit (200) to the purification unit (100),
- in the purification unit (100)
- introducing the warm crude argon stream into a first separation stage (101 ) comprising a pressure swing adsorption unit (4),
- withdrawing an oxygen-depleted crude argon stream (5, 7) and an argon- depleted first waste stream (6) from the first separation stage,
- introducing the oxygen-depleted crude argon stream (5, 7) into a second separation stage (102) for further removing oxygen by catalytic combustion (12) with hydrogen (21) to produce an oxygen-free stream (13, 16, 18, 24),
- withdrawing the oxygen-free argon stream (24) from the second separation stage (102),
- introducing the oxygen-free argon stream (24) into a third separation stage
(103) comprising a heat exchanger (25) and a distillation column (28),
- recovering a final pure argon product (35/36) from the lower portion of the distillation column (28). 2. Process according to claim 1 , wherein at least a portion of the final pure argon product from the lower portion of the distillation column (28) is recovered as a liquid stream (35 - LAR).
3. Process according to claim 1 or 2, wherein at least a portion of the final pure argon product from the lower portion of the distillation column (28) is recovered as a gaseous stream (36 - GAR).
4. Process according to any of the preceding claims, wherein, in the second separation stage (102), the oxygen-free stream (13, 16, 18) is sent to an adsorptive drier (19) prior to its introduction into the third separation stage (103).
5. Process according to any of the preceding claims, wherein the gaseous warm crude argon stream (1) is pressurized in a compressor (2) upstream the first separation stage (101).
6. Process according to any of the preceding claims, wherein
- the oxygen-free argon stream (24) from the second separation stage (102) is at least partially liquefied in a bottom reboiler (26) of the distillation column (28) of the third separation stage, and
- the liquefied portion (27) from the bottom reboiler (26) is sent into the distillation column at an intermediate height.
7. Process according to any of the preceding claims, wherein
- the argon-depleted first waste stream (6, 104) from the first separation stage is introduced into a fourth separation stage (105),
- an argon-enriched effluent stream (106) is withdrawn from the fourth separation stage (105) and
- mixed with the crude argon stream (1) upstream first separation stage 101.
8. Process according to any of the preceding claims, the fourth separation stage (105) comprising a further pressure swing adsorption unit and/or a membrane separation stage. Process according to any of the preceding claims, wherein no stream from the purification unit (100) is introduced into the first coldbox set of the main unit (200). Process according to claim 9, wherein the single fluid flow between the first set of coldboxes (221 ) and the second set of coldboxes (37) is the warm crude argon stream (1 ). Process according to claim 9, wherein the warm crude argon stream (1 ) and a liquid nitrogen stream (30) are the only fluid flows between the first set of coldboxes (221 ) and the second set of coldboxes (37). Process according to any of the preceding claims, wherein the crude argon stream(1 ) is warmed to about ambient temperature in the main heat exchanger (205). Purification unit (100) for producing argon from crude argon configured to be used in a process according to any of the preceding claims comprising
- an inlet for a gaseous warm crude argon stream (1 ) containing oxygen and nitrogen,
- a first separation stage (101 ) comprising a pressure swing adsorption unit (4),
- a second separation stage (102) comprising a catalytic combustion (12),
- a third separation stage (103) comprising a heat exchanger (25) and a distillation column (28),
- flow connecting means between the inlet and the first separation stage (101 ) for introducing the gaseous warm crude argon stream (1 ) containing oxygen and nitrogen into the first separation stage (101 ) for removing oxygen in the pressure swing adsorption unit (4),
- means for withdrawing an oxygen-depleted crude argon stream (5, 7) and an argon-depleted first waste stream (6) from the first separation stage,
- means for introducing the oxygen-depleted crude argon stream (5, 7) into the second separation stage (102) for further removing oxygen by catalytic combustion (12) with hydrogen (21 ) to produce an oxygen-free stream (13, 16, 18, 24),
- means for withdrawing the oxygen-free argon stream (24) from the second separation stage (102), - means for introducing the oxygen-free argon stream (24) into a third separation stage (103) comprising a heat exchanger (25) and a distillation column (28), and
- means for recovering a final pure argon product (35/36) from the lower portion of the distillation column (28). Process for manufacturing an air separation plant by retrofitting an existing cryogenic air separation plant having a main unit (200) producing a warm crude argon product via a crude argon production line by adding a purification unit (100) according to claim 13 by connecting the crude argon production line of the main unit to the inlet of the purification unit for the gaseous warm crude argon stream (1) containing oxygen and nitrogen of the purification unit.
PCT/EP2023/025114 2022-04-14 2023-03-15 Process and apparatus for producing argon from crude argon WO2023198307A1 (en)

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2990689A (en) * 1954-11-19 1961-07-04 Independent Engineering Compan Method and apparatus for the production of argon
US3169845A (en) * 1958-05-23 1965-02-16 Union Carbide Corp Method of and apparatus for producing high purity inert gases
DD126953A1 (en) * 1975-12-01 1977-08-24
US4477265A (en) * 1982-08-05 1984-10-16 Air Products And Chemicals, Inc. Argon purification
US20070209508A1 (en) * 2006-03-10 2007-09-13 Graham David R Combined cryogenic distillation and PSA for argon production
US20170030640A1 (en) * 2015-07-31 2017-02-02 Hai Du Method and apparatus for increasing argon recovery in a cryogenic air separation unit integrated with a pressure swing adsorption system
EP2986924B1 (en) 2013-04-18 2017-07-12 Linde Aktiengesellschaft Retrofit device for the cryogenic separation of air, retrofit installation and method for retrofitting a low-temperature air separator facility

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2990689A (en) * 1954-11-19 1961-07-04 Independent Engineering Compan Method and apparatus for the production of argon
US3169845A (en) * 1958-05-23 1965-02-16 Union Carbide Corp Method of and apparatus for producing high purity inert gases
DD126953A1 (en) * 1975-12-01 1977-08-24
US4477265A (en) * 1982-08-05 1984-10-16 Air Products And Chemicals, Inc. Argon purification
US20070209508A1 (en) * 2006-03-10 2007-09-13 Graham David R Combined cryogenic distillation and PSA for argon production
EP2986924B1 (en) 2013-04-18 2017-07-12 Linde Aktiengesellschaft Retrofit device for the cryogenic separation of air, retrofit installation and method for retrofitting a low-temperature air separator facility
US20170030640A1 (en) * 2015-07-31 2017-02-02 Hai Du Method and apparatus for increasing argon recovery in a cryogenic air separation unit integrated with a pressure swing adsorption system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
H.-W. HARING: "Industrial Gases Processing", 2008, WILEY-VCH

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