Process and apparatus for steam-methane reforming

• US 7,087,651 B2
• Filed: 12/02/2002
• Issued: 08/08/2006
• Est. Priority Date: 12/05/2001
• Status: Expired due to Term

• Current Assignee: CompactGTL PLC
• Original Assignee: GTL Microsystems AG
• Inventors: Lee-Tuffnell, Clive Derek, Bowe, Michael Joseph, Zimmerman, Ian Frederick, Maude, Jason Andrew
• Primary Examiner(s): PARSA, JAFAR F
• Application Number:
  US10/497,235
• Publication Number:
  US 20050054737A1
• Time in Patent Office: 1,345 Days
• Field of Search: 518/700, 518/702, 518/704, 518/705
• US Class Current: 518/700
• CPC Class Codes: B01J 19/249 Plate-type reactors
• CPC Class Codes: B01J 19/2495 Net-type reactors
• CPC Class Codes: B01J 2219/00117 with two or more reactions in heat exchange with each other, such as an endothermic reaction in heat exchange with an exothermic reaction
• CPC Class Codes: B01J 2219/00135 Electric resistance heaters
• CPC Class Codes: B01J 2219/2453 Plates arranged in parallel
• CPC Class Codes: B01J 2219/2459 Corrugated plates
• CPC Class Codes: B01J 2219/2465 Two reactions in indirect heat exchange with each other
• CPC Class Codes: B01J 2219/2466 The same reactant stream undergoing different reactions, endothermic or exothermic
• CPC Class Codes: B01J 2219/2479 Catalysts coated on the surface of plates or inserts
• CPC Class Codes: B01J 2219/2482 Catalytically active foils; Plates having catalytically activity on their own
• CPC Class Codes: B01J 2219/2485 Metals or alloys
• CPC Class Codes: B01J 2219/2493 Means for assembling plates together, e.g. sealing means, screws, bolts
• CPC Class Codes: B01J 2219/2497 Size aspects, i.e. concrete sizes are being mentioned in the classified document
• CPC Class Codes: B01J 2219/2498 Additional structures inserted in the channels, e.g. plates, catalyst holding meshes
• CPC Class Codes: B01J 2219/3221 Corrugated sheets
• CPC Class Codes: B01J 2219/32408 Metal
• CPC Class Codes: B01J 2219/32466 comprising catalytically active material
• CPC Class Codes: B01J 2219/32475 involving heat exchange
• CPC Class Codes: C01B 2203/0233 the reforming step being a steam reforming step
• CPC Class Codes: C01B 2203/062 Hydrocarbon production, e.g. Fischer-Tropsch process
• CPC Class Codes: C01B 2203/0811 : by combustion of fuel
• CPC Class Codes: C01B 2203/0827 : at least part of the fuel being a recycle stream
• CPC Class Codes: C01B 2203/0883 : by indirect heat exchange
• CPC Class Codes: C01B 2203/1035 : Catalyst coated on equipment surfaces, e.g. reactor walls
• CPC Class Codes: C01B 2203/1052 : Nickel or cobalt catalysts
• CPC Class Codes: C01B 2203/1064 : Platinum group metal catalysts
• CPC Class Codes: C01B 2203/107 : Platinum catalysts
• CPC Class Codes: C01B 2203/1241 : Natural gas or methane
• CPC Class Codes: C01B 2203/142 : At least two reforming, decomposition or partial oxidation steps in series
• CPC Class Codes: C01B 2203/148 : involving a recycle stream to the feed of the process for making hydrogen or synthesis gas
• CPC Class Codes: C01B 2203/82 : Several process steps of C01B2203/02 - C01B2203/08 integrated into a single apparatus
• CPC Class Codes: C01B 2203/84 : Energy production
• CPC Class Codes: C01B 3/384 : the catalyst being continuously externally heated
• CPC Class Codes: C10G 2/32 : with the use of catalysts

Abstract

Methane is reacted with steam, to generate carbon monoxide and hydrogen in a first catalytic reactor; the resulting gas mixture can then be used to perform Fischer-Tropsch synthesis in a second catalytic reactor. In performing the steam/methane reforming, the gas mixture is passed through a narrow flow channel containing a catalyst structure on a metal substrate, and adjacent to a source of heat, in a time less than 0.5 s, so that only those reactions that have comparatively rapid kinetics will occur. Both the average temperature and the exit temperature of the channel are in the range 750° to 900° C. The ratio of steam to methane should preferably be 1.4 to 1.6, for example about 1.5. Almost all the methane will undergo the reforming reaction, almost entirely forming carbon monoxide. After performing Fischer-Tropsch synthesis, the remaining hydrogen is preferably used to provide heat for the reforming reaction.

Claims

1. A process for converting methane to longer chain hydrocarbons, the process comprising the steps of:

(a) mixing a feed gas comprising methane with steam for forming a gas mixture in which the ratio of steam to methane is in the range 1.2 to 2.0;

(b) subjecting the gas mixture to reforming for generating carbon monoxide and hydrogen in a catalytic reactor comprising several narrow flow channels between metal sheets, the flow channels being arranged alternately with channels for an exothermic reaction to provide a source of heat, so that the sheets separate the flow channels from the source of heat, the flow channel containing a fluid-permeable catalyst structure with a metal substrate to enhance heat transfer, and each flow channel being of length at 100 mm, causing the gas mixture to flow through the flow channels, wherein the residence time in the flow channels is less than 500 ms but at least 20 ms, and both the average temperature along the flow channels and the exit temperature of the flow channels are in the range 750°

C. to 900°

C.;

(c) subjecting the carbon monoxide and hydrogen from the reforming step to a subsequent Fischer-Tropsch synthesis;

(d) separating a gas stream including hydrogen from the resulting longer chain hydrocarbons; and

(e) subjecting the hydrogen-including gas stream to combustion in the channels for the exothermic reaction for providing at least part of the heat source for the reforming step.

2. A process as claimed in claim 1 wherein the reforming reaction step is carried out at atmospheric pressure.

3. A process as claimed in claim 1 wherein the reforming reaction step is carried out at an elevated pressure in the range 0 to 200 kPa above atmospheric pressure.

4. A process as claimed in claim 1 wherein the said ratio is in the range 1.4 to 1.6.

5. A process as claimed in claim 1 including carrying out the Fischer-Tropsch synthesis at a temperature of about 230°

C.

6. A process as claimed in claim 1 including the step of compressing the carbon monoxide and hydrogen from the reforming step to a higher pressure before being subjected to the subsequent Fischer-Tropsch synthesis.

7. A process as claimed in claim 1 wherein the residence time of the gas mixture in the reforming reactor is less than 100 ms.