Apparatus and methods for producing hydrogen

• US 20080005963A1
• Filed: 12/17/2004
• Published: 01/10/2008
• Est. Priority Date: 12/17/2004
• Status: Active Grant

• Current Assignee: Texaco Incorporated (Chevron Corp.)
• Original Assignee: Texaco Incorporated (Chevron Corp.)
• Inventors: Wheat, W., Sun, Hongqiao, Balasubramanian, Bhaskar, Mirkovic, Vesna
• Granted Patent: US 7,402,287 B2
• Time in Patent Office: Days
• US Class Current: 048/061
• CPC Class Codes: B01D 2256/16 Hydrogen
• CPC Class Codes: B01D 2259/403 using three beds
• CPC Class Codes: B01D 53/0446 Means for feeding or distributing gases
• CPC Class Codes: B01D 53/047 Pressure swing adsorption
• CPC Class Codes: B01J 2208/00637 Means for stopping or slowing down the reaction
• CPC Class Codes: B01J 2208/00646 Means for starting up the reaction
• CPC Class Codes: B01J 2219/00006 Large-scale industrial plants
• CPC Class Codes: B01J 2219/0004 Processes in series
• CPC Class Codes: B01J 2219/00202 at the reactor outlet
• CPC Class Codes: B01J 2219/00216 Parameter value calculated by equations
• CPC Class Codes: B01J 2219/00231 at the reactor inlet
• CPC Class Codes: C01B 2203/0244 the reforming step being an autothermal reforming step, e.g. secondary reforming processes
• 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 2203/0465 Composition of the impurity
• CPC Class Codes: C01B 2203/047 the impurity being carbon monoxide
• CPC Class Codes: C01B 2203/0475 the impurity being carbon dioxide
• CPC Class Codes: C01B 2203/048 the impurity being an organic compound
• CPC Class Codes: C01B 2203/0485 the impurity being a sulfur compound
• CPC Class Codes: C01B 2203/0495 the impurity being water
• CPC Class Codes: C01B 2203/1642 Controlling the product
• CPC Class Codes: C01B 2203/169 : Controlling the feed
• CPC Class Codes: C01B 3/382 : Multi-step processes
• CPC Class Codes: C01B 3/56 : by contacting with solids; Regeneration of used solids C01B3/508 takes precedence

Abstract

An apparatus and method for producing hydrogen. The apparatus includes a fuel processor, a purification unit and a system controller. The controller determines a calculated flow of reformate from the fuel processor and operates the purification unit based on the calculated flow. The calculated flow is derived from a process model of the fuel processor and known feed(s) to the fuel processor. The calculated flow of reformate is used to control the flow of reformate to adsorbent beds within the purification unit and can be used to control other materials flows within the apparatus. Means for reducing fluctuations in the pressure and/or flow rate of reformate flowing from the fuel processor to the purification unit are also disclosed. The purity of the hydrogen produced can be maintained by adjusting the operation of the purification unit in response to changes in reformate composition, pressure and/or flow rate.

Claims

1. An apparatus for producing hydrogen comprising:

a fuel processor capable of producing a flow of intermediate reformate comprising hydrogen and an impurity;

a purification unit disposed downstream of the fuel processor capable of removing impurity from the flow of intermediate reformate to produce a flow of hydrogen-enriched reformate;

a controller capable of determining a calculated flow of intermediate reformate from a process model of the fuel processor and operating the purification unit in part in response to the calculated flow of intermediate reformate.

2. The apparatus of claim 1, wherein the fuel processor comprises an oxidizer and a reformer.

3. The apparatus of claim 1, wherein the purification unit comprises a plurality of adsorbent beds and a valve assembly capable of selectively controlling the flow of intermediate reformate to one or more of the plurality of adsorbent beds.

4. The apparatus of claim 3, wherein the plurality of adsorbent beds comprises an adsorbent material for selectively adsorbing impurity from the flow of intermediate reformate.

5. The apparatus of claim 3, wherein the purification unit comprises a variable-speed motor capable of creating rotation between the valve assembly and the plurality of adsorbent beds

6. The apparatus of claim 1, further comprising a product sensor disposed downstream of the purification unit for sensing the hydrogen-enriched reformate and/or a hydrogen-depleted reformate to generate sensed product data, and wherein the controller operates the purification unit in part in response to the sensed product data.

7. The apparatus of claim 1, further comprising a product valve downstream of the purification unit for controlling the flow of hydrogen-enriched reformate out of the purification unit, the product valve comprising a variable opening valve operated in part in response to the calculated flow of intermediate reformate.

8. The apparatus of claim 1, further comprising a compression unit disposed downstream from the fuel processor, the compression unit capable of receiving the flow of intermediate reformate and producing a flow of compressed intermediate reformate for delivery to the purification unit.

9. The apparatus of claim 8, wherein the compression unit comprises a variable or fixed speed compressor and wherein the controller operates the purification unit independent of the speed of the compressor.

10. The apparatus of claim 8, further comprising a conduit having a variable opening valve capable of controlling a flow of supplemental fluid through the conduit to an inlet of the compression unit and wherein the controller operates the variable opening valve in part in response to the calculated flow of intermediate reformate.

11. The apparatus of claim 8, further comprising a sensor disposed upstream of the compression unit capable of sensing the pressure and/or flow rate of the intermediate reformate, and wherein the variable opening valve is operated in response to a sensed pressure and/or flow rate.

12. The apparatus of claim 11, and wherein the controller operates the purification unit in part in response to the sensed pressure and/or flow rate.

13. The apparatus of claim 1, further comprising a buffer disposed intermediate the fuel processor and purification unit for buffering the flow of intermediate reformate.

14. The apparatus of claim 1, further comprising a tank disposed downstream from the purification unit capable of receiving and storing the hydrogen-enriched reformate.

15. The apparatus of claim 1, further comprising a feed to the fuel processor comprising a fuel, air, water and mixtures thereof, and a feed sensor for sensing the feed and relaying feed data to the controller.

16. A method for producing hydrogen-enriched reformate, the method comprising the steps of:

producing a flow of intermediate reformate comprising hydrogen and an impurity in a fuel processor;

removing impurity from the intermediate reformate to produce a flow of hydrogen-enriched reformate;

determining a calculated flow of intermediate reformate to be produced by the fuel processor from a process model of the fuel processor; and

operating the purification unit in part in response to the calculated flow of intermediate reformate.

17. The method of claim 16, wherein the purification unit comprises a plurality of adsorbent beds comprising an adsorbent material capable of selectively adsorbing the impurity, and wherein impurity is removed from the flow of intermediate reformate by directing the flow through one or more of the plurality of adsorbent beds for an adsorption period.

18. The method of claim 17, wherein the purification unit is operated in response to the calculated flow of intermediate reformate by adjusting the adsorption period in response to the calculated flow of intermediate reformate.

19. The method of claim 17, wherein the purification unit further comprises a valve assembly capable of selectively controlling the flow of intermediate reformate to one or more of the plurality of adsorbent beds.

20. The method of claim 18, wherein the purification further comprises a variable speed motor capable of creating rotation between the valve assembly and the plurality of adsorbent beds, and wherein the adsorption period is adjusted by changing the speed of the motor.

21. The method of claim 16, further comprising compressing the intermediate reformate in a compression unit to produce a flow of compressed intermediate reformate prior to removing impurity therefrom.

22. The method of claim 21, wherein the intermediate reformate is compressed in a compressor driven by a fixed or variable speed motor and wherein the purification unit is operated independent of the speed of the compressor.

23. The method of claim 16, further comprising buffering the flow of intermediate reformate prior to removing impurity from the intermediate reformate.

24. The method of claim 16, further comprising sensing the hydrogen-enriched reformate to produce sensed product data and operating the purification unit in response to the sensed product data.

25. The method of claim 16, further comprising controlling the flow of hydrogen-enriched reformate out of the purification unit in response to the calculated flow of intermediate reformate.

26. The method of claim 24, further comprising sensing the hydrogen-enriched reformate to produce sensed product data and controlling the flow of hydrogen-enriched reformate out of the purification unit in response to sensed product data.

27. The method of claim 16, further comprising selecting a hydrogen-enriched reformate output and determining the calculated flow of intermediate reformate based on the selected hydrogen-enriched reformate output.

28. The method of claim 27, wherein the calculated flow of intermediate reformate is determined from a look-up table.

29. The method of claim 28, further comprising controlling a feed to the fuel processor in response to the calculated flow of intermediate reformate.

30. The method of claim 16, further comprising selecting one or more feeds to the fuel processor and wherein the calculated flow of intermediate reformate is determined in part from the selected feed(s).