Catalyst system for lean NOx reduction with hydrocarbons

Patent metadata

Field	Value
Publication number	US-9808763-B2
Application number	US-201514962385-A
Country	US
Kind code	B2
Filing date	Dec 8, 2015
Priority date	Dec 8, 2015
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

A NOx control system includes a lean NOx catalyst and an alcohol generator. The lean NOx catalyst includes a substrate and a hydrocarbon selective catalytic reduction (HC-SCR) catalyst disposed on the substrate. The HC-SCR catalyst catalyzes a reduction of NOx with an alcohol. The alcohol generator generates the alcohol.

First claim

We claim:

1. A NOx control system to selectively reduce NOx present in an exhaust, the NOx control system comprising:
a lean NOx catalyst including:
a substrate; and
a hydrocarbon selective catalytic reduction (HC-SCR) catalyst disposed on the substrate, wherein the HC-SCR catalyst catalyzes a reduction of NOx with an alcohol; and

an alcohol generator to generate the alcohol;
wherein the alcohol generator is a superacid catalyst disposed on the substrate and the superacid catalyst catalyzes a reaction to convert an exhaust constituent into the alcohol.

2. The NOx control system according to claim 1 , wherein the superacid catalyst catalyzes a hydration of an alkene present in the exhaust into the alcohol.

3. The NOx control system according to claim 2 , wherein the superacid catalyst catalyzes a cracking of an alkane present in the exhaust into the alkene.

4. The NOx control system according to claim 1 , wherein the superacid catalyst is sulfated zirconia.

5. The NOx control system according to claim 1 , wherein the alcohol generator includes a reductant injection system configured to synthesize the alcohol and inject the alcohol into the exhaust.

6. The NOx control system according to claim 5 , wherein the reductant injection system includes an autothermal reformer to generate a syngas from methane and the reductant injection system is configured to synthesize the alcohol from the syngas.

7. The NOx control system according to claim 5 , wherein the reductant injection system is configured to generate hydrogen gas from an electrolysis of water and react the hydrogen gas with carbon dioxide to synthesize the alcohol.

8. The NOx control system according to claim 5 , further comprising:
a controller configured to control the reductant injection system to inject the alcohol into the exhaust.

9. The NOx control system according to claim 8 , further comprising:
a sensor configured to send a signal to the controller, wherein the controller is configured to determine an amount of the alcohol to add to the exhaust in response to the signal and the controller is configured to control the reductant injection system to inject the alcohol into the exhaust based on the determined amount of the alcohol to add to the exhaust.

Assignees

• Caterpillar Inc

Inventors

• Ginter David
• Deng Ling
• Park Paul
• Fiveland Scott B

Classifications

• B01D53/9431

  Processes characterised by a specific device · CPC title

• B01D53/9495

  Controlling the catalytic process · CPC title

• B01D2251/21

  Organic compounds not provided for in groups B01D2251/206 or B01D2251/208 · CPC title

• B01D2255/904

  Multiple catalysts · CPC title

• B01D53/9459

  Removing one or more of nitrogen oxides, carbon monoxide, or hydrocarbons by multiple successive catalytic functions; systems with more than one different function, e.g. zone coated catalysts (layered catalysts with only one function B01D53/9413, B01D53/944 or B01D53/945) · CPC title