Method of denitrating exhaust gas
US6479026B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 1999 |
| Grant date | Nov 12, 2002 |
| Priority date | — |
| Expiry date | Sep 24, 2019 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D53/8634
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The present invention provides a method of denitrating exhaust gas, which can control the NOx removal efficiency of exhaust gas at 90% or higher while suppressing the release of unreacted ammonia to 0.1 ppm or less. The method carries out denitration of exhaust gas for removing nitrogen oxides with catalytic reduction by introducing a nitrogen-oxide-containing gas into a catalyst-filled reaction chamber and adding ammonia as reducing agent in an excessive amount to the same chamber. The method comprises the steps of: introducing exhaust gas and ammonia into a first denitrating catalyst layer disposed on the most upstream side in the gas stream to remove nitrogen oxides; supplying the gas into a first ammonia decomposing catalyst layer disposed on the downstream side of the first denitrating catalyst layer to control the ammonia content to be suitable for the subsequent denitrating process, the first ammonia decomposing catalyst layer having ability to oxidatively decompose unreacted ammonia into nitrogen and nitrogen oxides; then supplying the gas into a second denitrating catalyst layer disposed on the downstream side of the first ammonia decomposing catalyst layer; thereafter sup…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.