LOW PRESSURE DROP REFORMING EXCHANGER

• US 20050086864A1
• Filed: 01/05/2005
• Published: 04/28/2005
• Est. Priority Date: 07/18/2001
• Status: Active Grant

• Current Assignee: Kellogg Brown & Root LLC (KBR Incorporated)
• Original Assignee: Kellogg Brown & Root LLC (KBR Incorporated)
• Inventors: Burlingame, Robert, Hackemesser, Larry G., Czuppon, Thomas
• Granted Patent: US 8,216,531 B2
• Time in Patent Office: Days
• US Class Current: 48/127.900
• CPC Class Codes: B01J 19/30 Loose or shaped packing elements, e.g. Raschig rings or Berl saddles, for pouring into the apparatus for mass or heat transfer
• CPC Class Codes: B01J 2208/00221 comprising baffles for guiding the flow of the heat exchange medium
• CPC Class Codes: B01J 2208/00309 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 2208/00495 using insulating materials or refractories
• CPC Class Codes: B01J 2208/0053 Controlling multiple zones along the direction of flow, e.g. pre-heating and after-cooling
• CPC Class Codes: B01J 2219/30223 Cylinder
• CPC Class Codes: B01J 2219/30242 Star
• CPC Class Codes: B01J 2219/32296 Honeycombs
• CPC Class Codes: B01J 23/755 Nickel
• CPC Class Codes: B01J 35/026 Form of the solid particles B01J35/08 takes precedence
• CPC Class Codes: B01J 35/50 characterised by their shape or configuration
• CPC Class Codes: B01J 8/008 Details of the reactor or of the particulate material; Processes to increase or to retard the rate of reaction B01J8/0285, B01J8/067, B01J8/087, B01J8/1836 take precedence
• CPC Class Codes: B01J 8/0292 with stationary packing material in the bed, e.g. bricks, wire rings, baffles
• CPC Class Codes: B01J 8/067 Heating or cooling the reactor B01J8/062 takes precedence
• CPC Class Codes: C01B 2203/0844 the non-combustive exothermic reaction being another reforming reaction as defined in groups C01B2203/02 - C01B2203/0294
• CPC Class Codes: C01B 2203/141 At least two reforming, decomposition or partial oxidation steps in parallel
• CPC Class Codes: C01B 2203/142 At least two reforming, decomposition or partial oxidation steps in series
• CPC Class Codes: C01B 2203/82 Several process steps of C01B2203/02 - C01B2203/08 integrated into a single apparatus
• CPC Class Codes: C01B 3/382 Multi-step processes
• CPC Class Codes: C01B 3/384 the catalyst being continuously externally heated
• CPC Class Codes: Y02P 20/52 : using catalysts, e.g. selective catalysts

Abstract

Disclosed are a syngas production process and a reforming exchanger 100. The process involves passing a first portion of hydrocarbon feed mixed with steam and oxidant through an autothermal catalytic steam reforming zone to form a first reformed gas of reduced hydrocarbon content, passing a second portion of the hydrocarbon feed mixed with steam through an endothermic catalytic steam reforming zone to form a second reformed gas of reduced hydrocarbon content, and mixing the first and second reformed gases and passing the resulting gas mixture through a heat exchange zone for cooling the gas mixture and thereby supplying heat to the endothermic catalytic steam reforming zone. The endothermic catalytic steam reforming zone and the heat exchange zone are respectively disposed tube side and shell side within a shell-and-tube reforming exchanger 100. The reforming exchanger 100 comprises a plurality of tubes 118 packed with low pressure drop catalyst-bearing monolithic structures 200 wherein an inside diameter of the tubes 118 is less than 4 times a maximum edge dimension of the catalyst structures 200.

Claims

1. A syngas reforming exchanger, comprising:

an elongated shell having relatively high and low temperature ends;

a shell side fluid inlet adjacent the high temperature end for receiving a hot gas feed;

a tube side fluid inlet adjacent the low temperature end for receiving a feed mixture of hydrocarbon and steam;

a shell side fluid outlet fluidly isolated from the tube side fluid inlet by a tube sheet adjacent the low temperature end for discharging cooled gas;

a tube bundle comprising a plurality of tubes and one or more longitudinally-spaced transverse baffle plates, wherein the tubes have an inlet end secured to the tube sheet for receiving the feed mixture and an outlet end adjacent the shell side fluid inlet for discharging reformed gas into the hot gas feed;

catalyst-bearing monolithic structures disposed within the tubes for converting the gas feed mixture to reformed gas, wherein the tubes have an inside diameter that is not more than 4 times a maximum edge dimension of the catalyst structures.

2. The apparatus of claim 1 wherein the tubes have an L_t/D_t ratio of at least 300 wherein L_t is taken as the length of the catalyst bearing extent of the tubes and D_t is the inside diameter of the tubes.

3. The apparatus of claim 2 wherein an overall heat transfer rate is at least 5 percent greater for a given pressure drop than Raschig rings measuring 0.31-in. long by 0.31-in. outside diameter by 0.125-in. inside diameter in tubes having an inside diameter of 2-in.

4. The apparatus of claim 1 wherein the catalyst-bearing monolithic structures comprise a twisted tape insert.

5. The apparatus of claim 2 wherein the catalyst-bearing monolithic structures comprise a twisted tape insert with a wash-coated surface impregnated with a nickel-containing catalyst.

6. The apparatus of claim 1 wherein the catalyst-bearing monolithic structures comprise a central longitudinal runner and a plurality of bristles extending transversely therefrom.

7. The apparatus of claim 2 wherein the catalyst-bearing monolithic structures comprise a central longitudinal runner, a plurality of bristles extending transversely therefrom and the bristles are wash-coated and impregnated with a nickel-containing catalyst.

8. The apparatus of claim 1 wherein the catalyst-bearing monolithic structures comprise ceramic foam.

9. The invention of claim 2 wherein the catalyst-bearing monolithic structures comprise ceramic foam made by filling voids in a sponge substrate with a fluidized ceramic and burning the substrate away to form the ceramic foam.

10. The apparatus of claim 9 wherein the ceramic foam is made in sheets, plugs are cut from the sheet having a diameter less than a thickness, and a plurality of the plugs are stacked end-to-end in each tube.

11. The apparatus of claim 1 wherein the catalyst-bearing monolithic structures comprise Raschig rings.

12. The apparatus of claim 1 wherein the inside diameter of the tubes is from 19 to 39 mm (0.75 to 1.55 inches).

13. The apparatus of claim 3 wherein a surface area of the catalyst-bearing monolithic structures for a given capacity is less than the Raschig rings in the 2-in. inside diameter tubes.

14. The apparatus of claim 13 wherein a catalyst volume of the catalyst-bearing monolithic structures for the given capacity is less than the Raschig rings in the 2-in. inside diameter tubes.