| 摘要 |
A process for treating an exhaust stream which includes high levels of noxious compounds containing chemically bound nitrogen, to produce an effluent stream that is low in oxides of nitrogen. A source of oxygen and fuel is added to the exhaust gas stream to create a fuel-rich mixture (16). The fuel-enriched stream is provided to a thermal reactor (18) and reacted to provide a heated oxygen-depleted stream which includes quantities of by-product NOx, which stream is then cooled (22). Oxygen is added to the cooled stream (19) which is passed over a first catalyst (25) under overall reducing conditions, whereby the NOx is first oxidized to NO2 , and then the NO2 is reduced by excess combustibles. The stream is cooled (40) and air is added to produce a further cooled stream (42) having a stoichiometric excess of oxygen. This is passed over an oxidizing catalyst (26) to oxidize remaining excess combustibles. |
