Method for the reduction of NOx and NH3 emissions
US7485273B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 9, 2007 |
| Grant date | Feb 3, 2009 |
| Priority date | — |
| Expiry date | Jun 6, 2027 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/12
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
This catalyst system simultaneously removes ammonia and enhances net NOx conversion by placing an NH3—SCR catalyst formulation downstream of a lean NOx trap. By doing so, the NH3—SCR catalyst adsorbs the ammonia from the upstream lean NOx trap generated during the rich pulses. The stored ammonia then reacts with the NOx emitted from the upstream lean NOx trap—enhancing the net NOx conversion rate significantly, while depleting the stored ammonia. By combining the lean NOx trap with the NH3—SCR catalyst, the system allows for the reduction or elimination of NH3 and NOx slip, reduction in NOx spikes and thus an improved net NOx conversion during lean and rich operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.