Selective catalytic reduction of NOx enabled by urea decomposition heat-exchanger bypass
US7815881B2 · kind B2 · utility
11Cited by
15References
8Claims
0Family size
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Key dates
| Filing date | Nov 10, 2009 |
| Grant date | Oct 19, 2010 |
| Priority date | — |
| Expiry date | Nov 10, 2029 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S423/05
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Disclosed are a process and apparatus for selective catalytic reduction of NOx. The process is enabled by bypassing a heat exchanger section, such as an economizer, of the boiler in advance of an SCR unit at low load conditions to enable NOx reduction even at low loads using urea instead of ammonia. In a preferred form, under high load conditions, the bypass can be almost fully closed and the economizer can be operated normally without excessively cooling the combustion gases, using only a portion of bypassed gases which are hot enough to decompose the urea into its active components including ammonia.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.