Pressure swing adsorption process for the production of hydrogen

{
  "publication_number": "US6503299B2",
  "country": "US",
  "kind": "B2",
  "title": "Pressure swing adsorption process for the production of hydrogen",
  "abstract": "This invention provides a two bed pressure swing adsorption process for recovering a primary gaseous component at a purity of over 99% from a feed gas comprising the primary component and one or more impurities. One such process includes: (a) passing the feed gas through a first adsorption bed to remove one or more impurities; (b) conducting a pressure swing adsorption cycle in the first bed; (c) separately passing effluent gases from the first bed into at least two separate tanks for subsequent purging and pressurization of the beds; (d) storing a gas mixture in the first of the tanks containing the primary component in a concentration higher than the concentration of the primary component in the gas mixture in the second of the tanks; (e) refluxing the mixture of the primary component from the second tank in the first adsorption bed during the regeneration steps therein; (f) refluxing the mixture of the primary component from the first tank in the first adsorption bed during the regeneration steps therein; (g) simultaneously and non-concurrently performing steps (a) to (f) in a second bed; and (h) recovering the product gas stream.",
  "claims": [
    "1. A two bed pressure swing adsorption process for recovering hydrogen at a purity of over 99% from a feed gas comprising hydrogen and one or more impurities, wherein the process uses a two bed pressure swing adsorption system and comprises: a. passing the feed gas through a first adsorption bed to remove one or more impurities; b. separately passing effluent gases from the first bed into at least two separate tanks for subsequent purging and pressurization of the two beds; c. storing a gas mixture in the first of the tanks containing hydrogen in a concentration that is at least 10% higher than the concentration of hydrogen in the gas mixture in the second of the tanks; d. refluxing the mixture of hydrogen from the second tank in the first adsorption bed during regeneration and depressurization steps therein; e. refluxing the mixture of hydrogen from the first tank in the first adsorption bed during said regeneration and depressurization steps therein; f. simultaneously and non-concurrently performing steps (a) to (e) in a second bed; and g. recovering hydrogen as a product gas stream.",
    "2. The process of claim 1, wherein the feed gas contains H 2, CO, CO 2, CH 4, N 2, and H 2 O.",
    "3. The process of claim 1, wherein the feed gas is continuously fed into the pressure swing adsorption system.",
    "4. The process of claim 1, wherein the time for one full cycle is between about 100 and about 400 seconds.",
    "5. The process of claim 1, further comprising at least one bed to bed equalization step.",
    "6. The process of claim 1, wherein the pressurization comprises, in sequence: i. equalization up; ii. equalization up and feed pressurization; iii. product pressurization using hydrogen gas having a purity of over 99% and feed pressurization; and iv. feed pressurization.",
    "7. The process of claim 1, wherein the depressurization comprises, in sequence: i. equalization down to said second bed; ii. equalization down to the first tank, iii. equalization down to the second tank; and iv blowdown.",
    "8. The process of claim 1, wherein the first and second beds each comprises an alumina layer at the feed end of the bed, a zeolite layer at the product end of the bed, and a carbon layer between the alumina layer and the zeolite layer.",
    "9. The process of claim 8, wherein the zeolite layer comprises a CaX zeolite or a VSA6 zeolite.",
    "10. A pressure swing adsorption process for recovering hydrogen at a purity of over 99% from a feed gas comprising hydrogen and one or more impurities, wherein the process uses a pressure swing adsorption system having two or more adsorption beds and comprises: a. passing the feed gas through an adsorption bed to remove one or more impurities; b. collecting effluent gases from the beds in at least two different storage tanks resulting in at least one storage tank having a hydrogen concentration that is at least 10% higher than the hydrogen concentration of at least one of the other storage tanks; c. refluxing a gas mixture containing increasing purities of hydrogen from the different storage tanks in an adsorption bed during regeneration steps therein; d. recovering hydrogen having a purity of over 99%.",
    "11. The process of claim 10, wherein the feed gas is continuously fed into the pressure swing adsorption system.",
    "12. The process of claim 10, wherein the time for one adsorption and desorption full cycle is between about 100 and about 400 seconds.",
    "13. The process of claim 10, further comprising at least one bed to bed equalization step.",
    "14. The process of claim 10, wherein the process includes pressurization steps which comprise, in sequence: i. equalization up; ii. equalization up and feed pressurization; iii. product pressurization using hydrogen gas having a purity of over 99.5% and feed pressurization; and iv. feed pressurization.",
    "15. The process of claim 10, wherein the process includes depressurization steps which comprise in order: i. equalization down; ii. equalization down to the first storage tank; iii. equalization down to the second storage tank; and iv. blowdown.",
    "16. The process of claim 10, wherein the process results in a hydrogen recovery of over 75% when said over 99.99%. 17.The process of claim 10, wherein the first and second beds each comprises an alumina layer at the feed end of the bed, a zeolite layer at the product end of the bed, and a carbon layer between the alumina layer and the zeolite layer.",
    "18. The process of claim 17, wherein the zeolite layer comprises a CaX zeolite or a VSA6 zeolite.",
    "19. The process of claim 10, wherein the feed gas impurities comprise nitrogen, carbon monoxide, carbon dioxide, methane and water."
  ],
  "cpc": [
    "B01D 53/047",
    "B01D 2253/102",
    "B01D 2253/104",
    "B01D 2253/108",
    "B01D 2259/40016",
    "B01D 2259/40024",
    "B01D 2259/40037",
    "B01D 2259/40052",
    "B01D 2259/402",
    "B01D 2259/4146",
    "B01D 53/02",
    "B01D 53/053",
    "C01B 2203/043",
    "C01B 2203/0465",
    "C01B 2203/047",
    "C01B 2203/0475",
    "C01B 2203/048",
    "C01B 2203/0495",
    "C01B 3/56",
    "Y02P 30/00"
  ],
  "assignees": [
    "PRAXAIR TECHNOLOGY INC"
  ],
  "filing_date": "1999-11-03",
  "publication_date": "2003-01-07",
  "grant_date": "2003-01-07",
  "priority_date": "1999-11-03",
  "application_number": "US-43221599-A",
  "family_id": "23715230",
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}