WO1991004788A1 - Carbon molecular sieve for breaking down air into nitrogen and oxygen by the alternating pressure technique - Google Patents

Carbon molecular sieve for breaking down air into nitrogen and oxygen by the alternating pressure technique Download PDF

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Publication number
WO1991004788A1
WO1991004788A1 PCT/EP1990/001659 EP9001659W WO9104788A1 WO 1991004788 A1 WO1991004788 A1 WO 1991004788A1 EP 9001659 W EP9001659 W EP 9001659W WO 9104788 A1 WO9104788 A1 WO 9104788A1
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Prior art keywords
gas
carbon molecular
oxygen concentration
minute
nitrogen
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PCT/EP1990/001659
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German (de)
French (fr)
Inventor
Hans Jürgen SCHRÖTER
Alfons Schulte
Michael Hein
Klaus-Dirk Henning
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Bergwerksverband Gmbh
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Publication of WO1991004788A1 publication Critical patent/WO1991004788A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
    • B01D53/047—Pressure swing adsorption
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
    • B01D2253/10—Inorganic adsorbents
    • B01D2253/116—Molecular sieves other than zeolites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
    • B01D2253/25—Coated, impregnated or composite adsorbents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2256/00—Main component in the product gas stream after treatment
    • B01D2256/10—Nitrogen
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/10—Single element gases other than halogens
    • B01D2257/104—Oxygen
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2259/00—Type of treatment
    • B01D2259/40—Further details for adsorption processes and devices
    • B01D2259/401—Further details for adsorption processes and devices using a single bed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
    • B01D53/047—Pressure swing adsorption
    • B01D53/0476—Vacuum pressure swing adsorption

Definitions

  • Carbon molecular sieve for the separation of air into nitrogen and oxygen using pressure swing technology Carbon molecular sieve for the separation of air into nitrogen and oxygen using pressure swing technology
  • the invention relates to a carbon molecular sieve for the separation of air into nitrogen and oxygen by pressure swing technology.
  • Carbon molecular sieves are used in pressure swing technology to separate gas mixtures. They differ from other adsorbents used in pressure swing technology, such as. B. zeolites and activated carbons, in that the separation of the gases takes place by different diffusion rates in the narrow micro-pores of the carbon molecular sieves. For example, the smaller oxygen molecule (gas kinetic diameter 2.8 AU) diffuses into the micropores considerably faster than the larger nitrogen molecule (gas kinetic diameter 3.0 AU). In the case of carbon molecular sieves, in contrast to zeolites, the oxygen is adsorbed in the pores, while the nitrogen penetrates the pores only to a very small extent and can therefore be obtained in an enriched form during the adsorption phase.
  • an oxygen rich gas is obtained. While If zeolites are used to obtain oxygen from air economically, the carbon molecular sieves are primarily suitable for the economical production of nitrogen due to the different separation effect described.
  • the object of the invention is to provide carbon molecular sieves which are particularly well suited for the "cutting technique" and are therefore highly specific Enable nitrogen generation rate and a low specific air requirement.
  • the carbon molecular sieve contained in the adsorber 1 absorbs gas due to its pore structure, the oxygen being preferentially adsorbed upstream of the nitrogen owing to the higher rate of diffusion.
  • the nitrogen mostly passes through the separation pores and exits at the end of the adsorber 1 via a line 9.
  • This process is ended after 2 minutes and the adsorber 1 is evacuated to 40 mbar in countercurrent via a line 10 by means of a vacuum pump 3.
  • an oxygen-enriched gas is obtained, which is introduced into a gasometer 5 via a line 11.
  • the maximum and the average oxygen concentration of this desorption gas, which is fed to an oxygen analyzer 6 via a line 12 is measured. Both values are compared to the oxygen concentration in air (21 vol .-? ⁇ ) increased.
  • the same process is then repeated with an adsorption time and a desorption time of 1 minute each.
  • Carbon molecular sieves are particularly well suited for use in pressure swing systems for the production of nitrogen from air using the "cutting technique” if the relative volume in the 1-minute test is lower and the mean and maximum oxygen concentration in the desorption gas in the 1-minute test are higher than in the 2-minute test.
  • carbon molecular sieves are unsuitable for the application of the "cutting technique", in which the relative volume in the 1-minute test is also lower than in the 2-minute test, but in which the mean and maximum oxygen concentration in the 1-minute test is lower than in the 2-minute test.
  • the pressure swing system used for the test purposes consisted of 2 4 1 adsorbers. It was operated at 8 bar adsorption pressure and 1 bar desorption pressure. Between the adsorption and desorption step, a pressure equalization was established by head / head and bottom / bottom connection, and then the adsorber to be desorbed was relaxed to a final pressure of 1 bar. The half cycle times (relaxation times) were varied between 60 and 240 seconds.
  • FIGS. 2 and 3 shows the nitrogen rate generated for various residual oxygen concentrations in the nitrogen product gas.
  • the carbon molecular sieve (A) which fulfills the conditions of claim 1 and the carbon molecular sieve (B) which does not meet these conditions were examined. In the first case, the "cutting technique" has increased the nitrogen generation rate, in the second case it has not.

Abstract

Carbon molecular sieve (CMS) for breaking down air into nitrogen and oxygen by the alternating pressure technique (PSA) having the properties described below. These properties are determined in a quality test in which a 200 ml container is filled with a carbon molecular sieve and air is first allowed to flow through for 2 minutes at 760 Torr, and then is evacuated for 2 minutes or 1 minute at 40 mbar. The gas volume collected (1 gas/1 CMS-volume = relative volume RV) as well as the average and maximum oxygen concentration are measured in the evacuation gas: a) attainment of a relative volume (RV) of 2.6 to 3.2 l gas/1 CMS in the 2-minute test; b) acquisition of a relative volume (RV) of 2.0 to 2.6 l gas/1 CMS in the 1-minute test; c) attainment of an average oxygen concentration of over 37 % vol. and a maximum oxygen concentration of over 64 % vol. in the evacuation gas in the 2-minute test, d) attainment of an average oxygen concentration and of a maximum oxygen concentration in the evacuation gas in the 1-minute test, which are above the values for the average and maximum oxygen concentrations in the 2-minute test.

Description

Kohlenstoff-Molekularsieb zur Zerlegung von Luft in Stickstoff und Sauerstoff durch Druckwechseltechnik Carbon molecular sieve for the separation of air into nitrogen and oxygen using pressure swing technology
Die Erfindung betrifft ein Kohlenstoff-Molekularsieb zur Zerlegung von Luft in Stickstoff und Sauerstoff durch Druck¬ wechseltechnik.The invention relates to a carbon molecular sieve for the separation of air into nitrogen and oxygen by pressure swing technology.
Kohlenstoff-Molekularsiebe werden bei der Druckwechseltech¬ nik zur Trennung von Gasgemischen verwendet. Sie unter¬ scheiden sich von anderen in der Druckwechseltechnik ver¬ wendeten Adsorptionsmitteln, wie z. B. Zeolithen und Aktiv¬ kohlen, dadurch, daß die Trennung der Gase durch unter¬ schiedliche Diffusionsgeschwindigkeiten in den engen Mikro- poren der Kohlenstoff-Molekularsiebe stattfindet. So dif¬ fundiert beispielsweise das kleinere Sauerstoffmolekül (gas¬ kinetischer Durchmesser 2,8 AE ) erheblich schneller in die Mikroporen als das größere Stickstoffmolekül (gaskinetischer Durchmesser 3,0 AE). Bei Kohlenstoff-Molekularsieben wird im Gegensatz zu Zeolithen der Sauerstoff in den Poren adsor¬ biert, während der Stickstoff nur in äußerst geringem Maße in die Poren eindringt und daher in angereicherter Form während der Adsorptionsphase gewonnen werden kann. Während der Desorption, z. B. durch Druckentspannung und/oder Evaku¬ ierung wird dann ein Sauerstoffreichgas gewonnen. Während mit Zeolithen wirtschaftlich im wesentlichen Sauerstoff aus Luft gewonnen wird, eignen sich die Kohlenstoff-Molekular¬ siebe aufgrund des geschilderten unterschiedlichen Trennef¬ fektes vornehmlich zur wirtschaftlichen Gewinnung von Stickstoff.Carbon molecular sieves are used in pressure swing technology to separate gas mixtures. They differ from other adsorbents used in pressure swing technology, such as. B. zeolites and activated carbons, in that the separation of the gases takes place by different diffusion rates in the narrow micro-pores of the carbon molecular sieves. For example, the smaller oxygen molecule (gas kinetic diameter 2.8 AU) diffuses into the micropores considerably faster than the larger nitrogen molecule (gas kinetic diameter 3.0 AU). In the case of carbon molecular sieves, in contrast to zeolites, the oxygen is adsorbed in the pores, while the nitrogen penetrates the pores only to a very small extent and can therefore be obtained in an enriched form during the adsorption phase. During desorption, e.g. B. by depressurization and / or evacuation then an oxygen rich gas is obtained. While If zeolites are used to obtain oxygen from air economically, the carbon molecular sieves are primarily suitable for the economical production of nitrogen due to the different separation effect described.
Bei den auf der Basis des Diffusionseffektes für Kohlen¬ stoff-Molekularsiebe entwickelten Druckwechseltechnik, wer¬ den zwei Adsorber verwendet. Während der eine Adsorber von Luft oder luftähnlichen Gasgemischen durchströmt und Sauerstoff adsorbiert wird, wird im anderen Adsorber durch Entspannung und/oder Vakuumanwendung Sauerstoff desorbiert.In the pressure swing technique developed on the basis of the diffusion effect for carbon molecular sieves, two adsorbers are used. While air or air-like gas mixtures flow through one adsorber and oxygen is adsorbed, oxygen is desorbed in the other adsorber by expansion and / or vacuum application.
Eine spezielle Ausführungsform der Druckwechseltechnik zur Lufttrennung mit Kohlenstoff-Molekularsieben ist in der noch nicht zum allgemeinen Stand der Technik zählenden deutschen Patentanmeldung P 38 30 506.2 vom 06. September 1988 be¬ schrieben. Bei diesem Verfahren wird die Desorption nach etwa 20 bis 80 % der Gesamtzeit der Desorptionsphase abge¬ brochen. Der Adsorber wird am Eingang und Ausgang verschlos¬ sen und verbleibt über die restliche Zeit im geschlossenen Zustand. Durch diese "Cutting-Technik" können die spezifi¬ sche Stickstofferzeugungsrate und die für den Energiever¬ brauch wesentliche Größe des spezifischen Luftbedarfs von einigen Kohlenstoff-Molekularsieben deutliche reduziert wer¬ den. Bei anderen Kohlenstoff-Molekularsieben ist dies da¬ gegen nicht möglich.A special embodiment of the pressure swing technique for air separation with carbon molecular sieves is described in the German patent application P 38 30 506.2 of September 6, 1988, which is not yet part of the general state of the art. In this process, the desorption is stopped after about 20 to 80% of the total time of the desorption phase. The adsorber is closed at the entrance and exit and remains in the closed state for the rest of the time. This "cutting technique" can significantly reduce the specific nitrogen generation rate and the size of the specific air requirement, which is essential for energy consumption, of some carbon molecular sieves. In contrast, this is not possible with other carbon molecular sieves.
Der Erfindung liegt die Aufgabe zugrunde, Kohlenstoff-Mole¬ kularsiebe bereitzustellen, die besonders gut für die "Cut¬ ting-Technik geeignet sind und somit eine hohe spezifische Stickstofferzeugungsrate sowie einen niedrigen spezifischen Luftbedarf ermöglichen.The object of the invention is to provide carbon molecular sieves which are particularly well suited for the "cutting technique" and are therefore highly specific Enable nitrogen generation rate and a low specific air requirement.
Bei der Anwendung der "Cutting-Technik" wurde nämlich über¬ raschend gefunden, daß dafür solche Kohlenstoff-Molekular¬ siebe besonders gut geeignet sind, die die in Anspruch 1 ge¬ nannten Eigenschaften aufweisen. Zur Auswahl der geeigneten Kohlenstoff-Molekularsiebe wird von einer Testmethode Ge¬ brauch gemacht, die den Besonderheiten des Trenneffektes - nämlich dem Unterschied in den Diffusionsgeschwindigkeiten von Stickstoff und Sauerstoff - Rechnung trägt. Der Druck¬ wechselprozeß wird in einer TestVorrichtung, wie in Fig. 1 der Zeichnung dargestellt, simuliert. Ein mit dem zu testen¬ den Kohlenstoff-Molekularsieb gefüllter Adsorber 1 (200 ml Inhalt) wird 2 Minuten lang von Luft durchströmt, die von einer Luftpumpe 2 über eine Leitung 8 unter einem Druck von 760 Torr zugeführt wird. In dieser Zeit nimmt das im Adsor¬ ber 1 enthaltene Kohlenstoff-Molekularsieb aufgrund seines Porengefüges Gas auf, wobei der Sauerstoff aufgrund der hö¬ heren Diffusionsgeschwindigkeit bevorzugt vor dem Stickstoff adsorbiert wird. Der Stickstoff passiert größtenteils die Trennporen und tritt am Ende des Adsorbers 1 über eine Leitung 9 wieder aus. Nach 2 Minuten wird dieser Vorgang beendet und der Adsorber 1 wird im Gegenstrom über eine Leitung 10 mittels einer Vakuumpumpe 3 auf 40 mbar evaku¬ iert. Hierbei wird ein an Sauerstoff angereichertes Gas gewonnen, das' über eine Leitung 11 in einen Gasometer 5 eingebracht wird. Die maximale und die mittlere Sauer¬ stoffkonzentration dieses Desorptionsgases, das über eine Leitung 12 einem Sauerstoff-Analysator 6 zugeführt wird, wird gemessen. Beide Werte sind gegenüber der Sauerstoffkon- zentration in Luft (21 Vol.-?ό) erhöht. Der gleiche Vorgang wird dann mit einer Adsorptionszeit und einer Desorptions- zeit von je 1 Minute wiederholt.When using the "cutting technique" it was surprisingly found that carbon molecular sieves which have the properties mentioned in claim 1 are particularly suitable for this purpose. To select the suitable carbon molecular sieves, use is made of a test method which takes into account the peculiarities of the separation effect - namely the difference in the diffusion rates of nitrogen and oxygen. The pressure change process is simulated in a test device, as shown in FIG. 1 of the drawing. An adsorber 1 (containing 200 ml) filled with the carbon molecular sieve to be tested is flowed through for 2 minutes by air, which is supplied by an air pump 2 via a line 8 under a pressure of 760 Torr. During this time, the carbon molecular sieve contained in the adsorber 1 absorbs gas due to its pore structure, the oxygen being preferentially adsorbed upstream of the nitrogen owing to the higher rate of diffusion. The nitrogen mostly passes through the separation pores and exits at the end of the adsorber 1 via a line 9. This process is ended after 2 minutes and the adsorber 1 is evacuated to 40 mbar in countercurrent via a line 10 by means of a vacuum pump 3. Here, an oxygen-enriched gas is obtained, which is introduced into a gasometer 5 via a line 11. The maximum and the average oxygen concentration of this desorption gas, which is fed to an oxygen analyzer 6 via a line 12, is measured. Both values are compared to the oxygen concentration in air (21 vol .-? ό) increased. The same process is then repeated with an adsorption time and a desorption time of 1 minute each.
Kohlenstoff-Molekularsiebe sind für den Einsatz in Druck¬ wechselanlagen zur Gewinnung von Stickstoff aus Luft unter Verwendung der "Cutting-Tεchnik" dann besonders gut geeig¬ net, wenn das Relativvolumen im 1-Minuten-Test niedriger und die mittlere und maximale Sauerstoffkonzentration im Desorptionsgas im 1-Minuten-Test höher sind als im 2-Mi- nuten-Test.Carbon molecular sieves are particularly well suited for use in pressure swing systems for the production of nitrogen from air using the "cutting technique" if the relative volume in the 1-minute test is lower and the mean and maximum oxygen concentration in the desorption gas in the 1-minute test are higher than in the 2-minute test.
Im Gegensatz dazu sind Kohlenstoff-Molekularsiebe für die Anwendung der "Cutting-Technik" ungeeignet, bei denen das Relativvolumen im 1-Minuten-Test zwar ebenfalls niedriger als im 2-Minuten-Test ist, bei dem aber die mittlere und die maximale Sauerstoffkonzentration im 1-Minuten-Test niedriger als im 2-Minuten-Test liegen.In contrast, carbon molecular sieves are unsuitable for the application of the "cutting technique", in which the relative volume in the 1-minute test is also lower than in the 2-minute test, but in which the mean and maximum oxygen concentration in the 1-minute test is lower than in the 2-minute test.
Ausführungsbeispieleembodiments
Zwei verschiedene Kohlenstoff-Molekularsiebe wurden anhand der geschilderten 1-Minuten- und 2-Minuten-Tests untersucht und charakterisiert und anschließend in einer kleinen Druck- ωechselanlage mit und ohne Anwendung der "Cutting-Technik" überprüft. Tabelle 1 zeigt ihre charakteristischen Daten, von denen das eine die Anforderungen des Anspruchs 1 erfüllt (A), das andere Molekularsieb jedoch nicht (B). Tabelle 1; Eigenschaften der untersuchten Kohlenstoff-Mole¬ kularsiebe nach dem 2-Minuten- und 1-Minuten-TestTwo different carbon molecular sieves were examined and characterized on the basis of the described 1-minute and 2-minute tests and then checked in a small pressure exchange system with and without the use of the "cutting technique". Table 1 shows their characteristic data, one of which meets the requirements of claim 1 (A) but the other does not (B). Table 1; Properties of the investigated carbon molecular sieves after the 2-minute and 1-minute test
Test CMS "A" CMS "B"Test CMS "A" CMS "B"
(gemäß Patentanspruch) (außerhalb Patentanspruch) 2 min-Test 1-min-Test 2 min-Test 1-min-Test(according to claim) (outside claim) 2 min test 1 min test 2 min test 1 min test
RV 2,7 2,15 2,47 2,03RV 2.7 2.15 2.47 2.03
(1 Gas/1 CMS) max. I -Konzen- 65,4 66 69,7 68,6 tration (Vol. -8) mittlere 0„-Kon- 40,2 46 49,5 49,4 zentration(1 gas / 1 CMS) max. I concentration 65.4 66 69.7 68.6 concentration (vol. -8) mean 0 "concentration 40.2 46 49.5 49.4 concentration
(Vol.-Ä)(Vol.-Ä)
Die für die Prüfzwecke verwendete Druckwechselanlage bestand aus 2 4 1-Adsorbern. Sie wurde bei 8 bar Adsorptionsdruck und 1 bar Desorptionsdruck betrieben. Zwischen Adsorptions¬ und Desorptionsschritt wurde ein Druckausgleich durch Kopf/Kopf- und Boden/Boden-Verbindung hergestellt, an¬ schließend wurde der zu desorbierende Adsorber bis auf einen Enddruck von 1 bar entspannt. Die halben Zykluszeiten (Ent¬ spannungszeiten) wurden zwischen 60 und 240 Sekunden vari¬ iert.The pressure swing system used for the test purposes consisted of 2 4 1 adsorbers. It was operated at 8 bar adsorption pressure and 1 bar desorption pressure. Between the adsorption and desorption step, a pressure equalization was established by head / head and bottom / bottom connection, and then the adsorber to be desorbed was relaxed to a final pressure of 1 bar. The half cycle times (relaxation times) were varied between 60 and 240 seconds.
Zur Untersuchung der Cutting-Technik wurde die Entspannung nach 20 bis 80 % dieser Zeit abgebrochen. Der Druck hatte zu diesem Zeitpunkt im Adsorber bereits 1 bar erreicht. Nachdem der Adsorber über das Eingangs- und das Ausgangsventil ver- schlössen wurde, stieg dieser Druck wieder auf Zwischen¬ drucke um etwa 2 - 4 bar an. Danach erfolgte der Druckaus¬ gleich und ein teilweises Rückführen des erzeugten Stick¬ stoffs in den Adsorber. Anschließend wurde dann in der übli¬ chen Weise wieder Luft eingeleitet, wobei am Ende des Ad- sorbers Stickstoff produziert wurde. Dieser Vorgang wurde zyklisch mehrfach wiederholt. Es wurden die erzeugte Stick¬ stoffmenge in m Stickstoff pro m CMS Volumen und pro Stun¬ de gemessen sowie der zur Erzeugung' von 1 m Stickstoff be¬ nötigte Luftbedarf bzw. das Verhältnis Luft/Stickstoff er¬ mittelt.To investigate the cutting technique, the relaxation was stopped after 20 to 80% of this time. At this point the pressure in the adsorber had already reached 1 bar. After the adsorber is connected via the inlet and outlet valve was closed, this pressure rose again to intermediate pressures by about 2-4 bar. This was followed by pressure equalization and a partial return of the nitrogen produced to the adsorber. Then air was again introduced in the usual way, nitrogen being produced at the end of the adsorber. This process was repeated several times cyclically. There were generated Stick¬ molar amount m of nitrogen per m CMS volume and measured per Stun de and averages the be¬ for the production 'of 1 m nitrogen forced air demand and the ratio air / nitrogen er¬.
Die Ergebnisse der verschiedenen Versuche sind in den Figu¬ ren 2 und 3 dargestellt. Fig. 2 zeigt die erzeugte Stick¬ stoffrate für verschiedene Restsauerstoffkonzentrationen im Stickstoffproduktgas. Untersucht wurden das Kohlenstoff-Mo¬ lekularsieb (A), das die Bedingungen des Anspruchs 1 er¬ füllt, und das Kohlenstoff-Molekularsieb (B), das diese Be¬ dingungen nicht erfüllt. Im ersteren Fall ist durch die "Cutting-Technik" die Stickstofferzeugungsrate erhöht wor¬ den, im zweiten Fall nicht.The results of the various tests are shown in FIGS. 2 and 3. 2 shows the nitrogen rate generated for various residual oxygen concentrations in the nitrogen product gas. The carbon molecular sieve (A) which fulfills the conditions of claim 1 and the carbon molecular sieve (B) which does not meet these conditions were examined. In the first case, the "cutting technique" has increased the nitrogen generation rate, in the second case it has not.
In Fig. 3 ist für beide Kohlenstoff-Molekularsiebe (A) und (B) der spezifische Luftbedarf, der für die Erzeugung eines m Stickstoff notwendig ist, für verschiedene Sauerstoff¬ restkonzentrationen im Produktgas aufgetragen worden. Hier¬ aus wird noch sehr viel deutlicher, daß durch Anwendung der "Cutting-Technik" das für den Energieverbrauch (Energie zur Kompression der zur Trennung vorgesehenen. Luf.t) wichtige Luft/Stickstoff-Verhältnis bei Verwendung des Kohlen¬ stoff-Molekularsiebes (A), das den Bedingungen des Anspru- ches 1 genügt, erheblich reduziert werden kann. Dies gelingt bei dem Kohlenstoff-Molekularsieb (B), das die Bedingungen des Anspruches 1 nicht erfüllt, praktisch nicht. Besonders günstig wirkt sich die "Cutting-Technik" bei der Herstellung von N„ mit 99,9 % und reiner aus. In FIG. 3 the specific air requirement, which is necessary for the generation of a nitrogen, for different residual oxygen concentrations in the product gas has been plotted for both carbon molecular sieves (A) and (B). From this it becomes much clearer that by using the "cutting technique" the air / nitrogen ratio important for energy consumption (energy for compressing the air. T) intended for separation when using the carbon molecular sieve ( A) that meets the conditions of the claim ches 1 is sufficient, can be significantly reduced. This is practically not possible with the carbon molecular sieve (B), which does not meet the conditions of claim 1. The "cutting technique" has a particularly favorable effect in the production of N "with 99.9% and more pure.

Claims

PatentanspruchClaim
Kohlenstoff-Molekularsieb (CMS) zur Zerlegung von Luft in Stickstoff und Sauerstoff durch Druckwechseltechnik (P5A), gekennzeichnet durch folgende Eigenschaften, die in einem Qualitätstest ermittelt werden, bei dem ein mit Kohlen¬ stoff-Molekularsieb gefüllter 200 ml-Behälter zunächst 2 Mi¬ nuten bzw. 1 Minute bei 760 Torr von Luft durchströmt wird und anschließend 2 Minuten bzw. 1 Minute auf 40 mbar evaku¬ iert wird und wobei das aufgenommene Gasvolumen (1 Gas/1 CMS-Volumen = Relativvolumen RV) sowie die mittlere und maximale Sauerstoffkonzentration im Evakuierungsgas gemessen werden:Carbon molecular sieve (CMS) for the separation of air into nitrogen and oxygen by pressure swing technology (P5A), characterized by the following properties, which are determined in a quality test in which a 200 ml container filled with carbon molecular sieve initially contains 2 ml grooves or 1 minute at 760 Torr of air and then 2 minutes or 1 minute is evacuated to 40 mbar and the gas volume taken up (1 gas / 1 CMS volume = relative volume RV) and the mean and maximum oxygen concentration measured in the evacuation gas:
a) Erzielung eines Relativvolumens (RV) von 2,6 bis 3,2 1 Gas/1 CMS im 2-Minuten-Test,a) achieving a relative volume (RV) of 2.6 to 3.2 1 gas / 1 CMS in the 2-minute test,
b) Erzielung eines Relativvolumens (RV) von 2,0 bis 2,6 1 Gas/1 CMS im 1-Minuten-Test,b) achieving a relative volume (RV) of 2.0 to 2.6 1 gas / 1 CMS in a 1-minute test,
c) Erzielung einer mittleren Sauerstoffkonzentration ober¬ halb von 37 Vol.-?. und einer max. Sauerstoffkonzentration oberhalb von 64 Vol.-?£ im Evakuierungsgas im 2-Minuten- Test,c) Achieving an average oxygen concentration above 37 vol.?. and a max. Oxygen concentration above 64 vol .-? £ in the evacuation gas in the 2-minute test,
d) Erzielung einer mittleren Sauerstoffkonzentration und ei¬ ner max. Sauerstoffkonzentration im Evakuierungsgas im 1-Minuten-Test, die oberhalb der Werte für die mittleren und maximalen Sauerstoffkonzentrationen im 2-Minuten-Test liegen. d) achieving an average oxygen concentration and a max. Oxygen concentration in the evacuation gas in the 1-minute test, which is above the values for the mean and maximum oxygen concentrations in the 2-minute test.
PCT/EP1990/001659 1989-10-06 1990-10-03 Carbon molecular sieve for breaking down air into nitrogen and oxygen by the alternating pressure technique WO1991004788A1 (en)

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DE19893933441 DE3933441A1 (en) 1989-10-06 1989-10-06 CARBON MOLECULAR SCREEN FOR THE DISASSEMBLY OF AIR IN NITROGEN AND OXYGEN BY PRESSURE EXCHANGE TECHNOLOGY

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WO2024015292A1 (en) * 2022-07-12 2024-01-18 ExxonMobil Technology and Engineering Company Oxygen-enriched combustion for natural gas combined cycle operation

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US4420415A (en) * 1980-08-27 1983-12-13 Director-General Of Agency Of Industrial Science & Technology Process for the production of carbon molecular sieves
DE3618426C1 (en) * 1986-05-31 1987-07-02 Bergwerksverband Gmbh Process for the production of carbon molecular sieves
US4742040A (en) * 1986-01-29 1988-05-03 Kuraray Chemical Co., Ltd. Process for manufacturing a carbon molecular sieve
EP0282053A2 (en) * 1987-03-10 1988-09-14 Kanebo, Ltd. Molecular sieving carbon, process for its production and its use

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US4540678A (en) * 1982-09-07 1985-09-10 Calgon Carbon Corporation Carbon molecular sieves and a process for their preparation and use

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Publication number Priority date Publication date Assignee Title
US4420415A (en) * 1980-08-27 1983-12-13 Director-General Of Agency Of Industrial Science & Technology Process for the production of carbon molecular sieves
US4742040A (en) * 1986-01-29 1988-05-03 Kuraray Chemical Co., Ltd. Process for manufacturing a carbon molecular sieve
DE3618426C1 (en) * 1986-05-31 1987-07-02 Bergwerksverband Gmbh Process for the production of carbon molecular sieves
EP0282053A2 (en) * 1987-03-10 1988-09-14 Kanebo, Ltd. Molecular sieving carbon, process for its production and its use

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