Vehicle powertrain with on-board catalytic reformer

Patent metadata

Field	Value
Publication number	US-11215148-B2
Application number	US-201916502275-A
Country	US
Kind code	B2
Filing date	Jul 3, 2019
Priority date	Jul 12, 2018
Publication date	Jan 4, 2022
Grant date	Jan 4, 2022

Abstract

A power system comprises an engine configured to combust an air/fuel mixture and produce a flow of exhaust gas; an exhaust passageway fluidly connected to the engine to receive the flow of exhaust gas; an exhaust gas recirculation loop fluidly connecting the exhaust passageway to a fuel intake for the engine; a first conversion zone containing a fuel reforming catalyst located within the exhaust gas recirculation loop; and a second conversion zone located within the exhaust gas recirculation loop separate from and downstream of the first conversion zone stream, the second conversion zone containing a fuel cracking catalyst.

First claim

We claim:

1. A method of operating a power system comprising,
an engine configured to combust an air/fuel mixture and produce a flow of exhaust gas;
an exhaust passageway fluidly connected to the engine to receive the flow of exhaust gas;
an exhaust gas recirculation loop fluidly connecting the exhaust passageway to a fuel intake for the engine;
a first conversion zone containing a fuel reforming catalyst located within the exhaust gas recirculation loop; and
a second conversion zone located within the exhaust gas recirculation loop separate from and downstream of the first conversion zone stream, the second conversion zone containing a fuel cracking catalyst,
the method comprising:
(a) supplying a mixture comprising exhaust gas and a first hydrocarbon-containing fuel to an inlet of the first conversion zone at a first temperature to convert a portion of the fuel in the presence of the reforming catalyst into CO and H 2 to produce a reformed gaseous mixture, wherein the first temperature, as measured at the inlet to the first conversion zone, is in a range from greater than 550° C. to about 700° C.;
(b) supplying the reformed gaseous mixture to the second conversion zone at a second temperature lower than the first temperature to convert paraffins in a further portion of the fuel in the presence of the cracking catalyst into olefins to produce a reformed and cracked gaseous mixture;
(c) introducing at least a portion of the reformed and cracked gaseous mixture and a second hydrocarbon-containing fuel into the engine, wherein said second hydrocarbon-containing fuel may be the same or different from the first hydrocarbon-containing fuel;
(d) combusting the at least a portion of the reformed and cracked gaseous mixture and second hydrocarbon-containing fuel in the engine to form an exhaust gas; and
(e) recycling part of the exhaust gas to step (a).

2. The method of claim 1 , wherein the mixture supplied to the first conversion zone in (a) further comprises air.

3. The method of claim 2 and further comprising adjusting the amount of air supplied to the first conversion zone in (a) according to the first temperature.

4. The method of claim 1 , wherein the second temperature, as measured at the inlet to the second conversion zone, is from 500 to 550° C. in (b).

5. The method of claim 1 , wherein the fuel to air ratio in the mixture supplied to the first conversion zone is controlled at a first value during step (a) wherein the mixture is fuel-rich with respect to combustion stoichiometry.

6. The method of claim 5 and further comprising:
(f) periodically adjusting the fuel to air ratio in the mixture supplied to the first conversion zone to a second value wherein the mixture is air-rich with respect to combustion stoichiometry to effect regeneration of the reforming catalyst.

7. The method of claim 6 , wherein air is also supplied to the second conversion zone during step (f).

8. The method of claim 6 , wherein the mixture supplied to the first conversion zone is at the first value for a time t1 and is at the second value for a time t2, wherein the ratio of t1:t2 is at least 5.

9. The method of claim 8 , wherein time t2 is less than or equal to 10 minutes.

10. The method of claim 1 , wherein the reformed and cracked gaseous mixture produced in (b) has a higher octane number and LHV than the mixture supplied to the first conversion zone in (a).

11. The method of claim 1 , wherein the fuel reforming catalyst comprises rhodium on a refractory support.

12. The method of claim 11 , wherein the refractory support comprises a metal oxide and/or a molecular sieve.

13. The method of claim 11 , wherein the refractory support comprises a metal oxide selected from the group consisting of alumina, silica, silica-alumina, lanthana, ceria, zirconia and mixtures thereof.

14. The method of claim 11 , wherein the refractory support comprises a molecular sieve having the CHA structure type.

15. The method of claim 1 , wherein the fuel cracking catalyst comprises metal-promoted MCM-68.

16. The method of claim 15 , wherein the metal is selected from the group consisting of platinum, zinc, gallium and mixtures thereof.

17. The method of claim 11 , wherein the weight ratio of the fuel cracking catalyst to the rhodium on the fuel reforming catalyst is at least 20.

18. The method of claim 1 , wherein the power system further comprises:
a first injector for supplying air to the first conversion zone;
a second injector operable independently of the first injector for supplying air to the second conversion zone.

19. The method of claim 1 , wherein the power system further comprises:
a pre-combustion catalyst located within the exhaust gas recirculation loop upstream of the fuel reforming catalyst for raising the temperature of the exhaust gas by catalytic partial oxidation of fuel.

Assignees

• Exxonmobil Res & Eng Co
• Toyota Chuo Kenkyusho Kk

Inventors

• MERCHANT Shamel
• Choi Eugine
• Weissman Walter
• Beutel Tilman W
• Brody John F
• Majano Gerardo
• Strohmaier Karl G
• Weiss Brian
• Colby Robert J
• Koike Makoto
• Miyagawa Hiroshi
• Yamamoto Seiji

Classifications

• C10G47/14

  the catalyst containing platinum group metals or compounds thereof · CPC title

• B01J29/7476

  MWW-type, e.g. MCM-22, ERB-1, ITQ-1, PSH-3 or SSZ-25 · CPC title

• F02M26/35 Primary

  with means for cleaning or treating the recirculated gases, e.g. catalysts, condensate traps, particle filters or heaters · CPC title

• B01J29/7088

  MWW-type, e.g. MCM-22, ERB-1, ITQ-1, PSH-3 or SSZ-25 · CPC title

• F02M26/36 Primary

  with means for adding fluids other than exhaust gas to the recirculation passage; with reformers · CPC title