Denitrification of flue gas from catalytic cracking
US5173278A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 15, 1991 |
| Grant date | Dec 22, 1992 |
| Priority date | — |
| Expiry date | Mar 15, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P30/40
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A flue gas that contains small amounts of both HCN and NO.sub.x, produced, for example, by catalyst regeneration in the fluid catalytic cracking of a petroleum gas oil, is readily denitrified by the catalyzed reaction that proceeds approximately according to: EQU HCN+NO.fwdarw.N.sub.2 (gas)+CO+CO.sub.2 +H.sub.2 O If the molar ratio of HCN to NO in the flue gas is about 1.0, e.g. in the range of about 0.8 to 1.2, effective denitrification is achieved without first changing the composition of the flue gas by contacting it with catalyst under conversion conditions including elevated temperature. If the molar ratio of HCN to NO exceeds 1.2, the ratio may be adjusted to about 1.0 to 1.1 by thermal or catalytic oxidation in the presence of oxygen gas, followed by catalytic denitrification. If the molar ratio is less than about 0.8, the effective molar ratio is adjusted to about 1.0 to 1.1 by adding NH.sub.3 gas, followed by denitirification. In all three instances an excessive content of carbon monoxide in the flue gas may be corrected by passing the denitrified flue gas to a CO-boiler. Catalysts for the denitrification reaction are described and exemplified by crystalline zeolites of th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.