Six bed pressure swing adsorption process operating in normal and turndown modes

• US 8,491,704 B2
• Filed: 01/11/2011
• Issued: 07/23/2013
• Est. Priority Date: 01/11/2011
• Status: Active Grant

• Current Assignee: Praxair Technology Incorporated (Linde Plc)
• Original Assignee: Praxair Technology Incorporated (Linde Plc)
• Inventors: Baksh, Mohamed S. A., Simo, Marian
• Primary Examiner(s): LAWRENCE JR, FRANK M
• Application Number:
  US13/004,706
• Publication Number:
  US 20120174776A1
• Time in Patent Office: 924 Days
• Field of Search: 95/96, 951/17, 951/30, 951/27, 951/39, 951/40, 951/43
• US Class Current: 95/96
• CPC Class Codes: B01D 2253/102 Carbon
• CPC Class Codes: B01D 2253/104 Alumina
• CPC Class Codes: B01D 2253/108 Zeolites
• CPC Class Codes: B01D 2253/304 Linear dimensions, e.g. particle shape, diameter
• CPC Class Codes: B01D 2256/16 Hydrogen
• CPC Class Codes: B01D 2257/102 Nitrogen
• CPC Class Codes: B01D 2257/11 Noble gases
• CPC Class Codes: B01D 2257/502 Carbon monoxide
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2257/7022 Aliphatic hydrocarbons
• CPC Class Codes: B01D 2257/7025 Methane
• CPC Class Codes: B01D 2257/80 Water
• CPC Class Codes: B01D 2259/40039 with three sub-steps
• CPC Class Codes: B01D 2259/40041 with more than three sub-steps
• CPC Class Codes: B01D 2259/40075 More than ten
• CPC Class Codes: B01D 2259/4061 using five beds
• CPC Class Codes: B01D 2259/4062 using six beds
• CPC Class Codes: B01D 2259/4145 arranged in series
• CPC Class Codes: B01D 53/047 Pressure swing adsorption
• CPC Class Codes: C01B 2203/0233 the reforming step being a steam reforming step
• CPC Class Codes: C01B 2203/043 : Regenerative adsorption process in two or more beds, one for adsorption, the other for regeneration
• CPC Class Codes: C01B 2203/1241 : Natural gas or methane
• CPC Class Codes: C01B 3/56 : by contacting with solids; Regeneration of used solids C01B3/508 takes precedence
• CPC Class Codes: Y02C 20/20 : of methane
• CPC Class Codes: Y02C 20/40 : of CO2
• CPC Class Codes: Y02P 20/151 : Reduction of greenhouse gas [GHG] emissions, e.g. CO2
• CPC Class Codes: Y02P 20/156 : Methane [CH4]

Abstract

The present invention relates to a six bed pressure swing adsorption (PSA) system utilizing new and advanced cycles to obtain enhanced hydrogen recovery from a hydrogen containing feed gas (i.e., synthesis gas). In one such cycle each of the six beds has four pressure equalization steps, and at least one of the beds is receiving and processing said feed gas to obtain a hydrogen product gas (i.e., a 6-1-4 cycle).

Claims

1. A pressure swing adsorption process for separating a pressurized supply feed gas containing one or more strongly adsorbable component from at least one less strongly adsorbable product gas component in a six bed adsorbent system to produce a continuous stream of product gas enriched in the less strongly adsorbable component and a continuous stream of offgas that is enriched in the strongly adsorbable components;

wherein, the process cycle has eighteen steps including four bed-to-bed equalization steps, in accordance to following cycle chart;

2. The pressure swing adsorption process of claim 1, wherein the six bed system is in turndown mode with five beds online, where the process cycle has fifteen steps including three bed-to-bed equalizations steps, while one of the beds is in production.

3. The pressure swing adsorption process of claim 1, wherein said less strongly adsorbable product gas is hydrogen.

4. The pressure swing adsorption process of claim 1, wherein the supply feed gas contains one or more strongly adsorbable component selected from the group consisting of hydrocarbons, carbon dioxide, carbon monoxide, argon, nitrogen and water vapor.

5. The pressure swing adsorption process of claim 1, wherein each adsorbent bed contains alumina, carbon and zeolite material configured in layers in this particular order.

6. The pressure swing adsorption process of claim 5, where the carbon and zeolite layers are each subdivided into two layers with different particle size.

7. The pressure swing adsorption process of claim 6, where the first of the subdivided carbon layers encountered by the supply feed gas has a particle size of about 0.5 to 1.5 mm and an affinity for the carbon dioxide impurity.

8. The pressure swing adsorption process of claim 6, where the second of the subdivided carbon layers encountered by the supply feed gas has a particle size of about 2.0 to 3.0 mm and an affinity for the methane impurities.

9. The pressure swing adsorption process of claim 6, where the first of the subdivided zeolite layers encountered by the supply feed gas has a particle size of about 0.5 to 2.0 mm and an affinity for the carbon monoxide impurity.

10. The pressure swing adsorption process of claim 6, where the second of the subdivided zeolite layers encountered by the supply feed gas has a particle size of about 2.0 to 3.0 mm and an affinity for the nitrogen impurity.

11. A pressure swing adsorption process for separating a pressurized supply feed gas containing one or more strongly adsorbable component from at least one less strongly adsorbable product gas component in a five bed adsorbent system to produce a continuous stream of product gas enriched in the less strongly adsorbable component and a continuous stream of offgas that is enriched in the strongly adsorbable components;

wherein, the process cycle has fifteen steps including three bed-to-bed equalization steps, in accordance with the following cycle chart;

12. A pressure swing adsorption process for separating a pressurized supply feed gas containing one or more strongly adsorbable component from at least one less strongly adsorbable product gas in a six bed adsorbent system where the process cycle has eighteen steps including three bed-to-bed equalizations steps, while two of the beds are in production, in accordance to following cycle chart: