| 摘要 |
A process and system for low NOx cogeneration to produce electricity and useful heat. Fuel (12) and oxygen (14) are provided to an internal combustion engine (10) connected to drive an electric generator (9), to thereby generate electricity. An exhaust stream is recovered from the engine at a temperature of about 500 DEG to 1000 DEG F which includes from about 6 to 15 percent oxygen. Fuel is added to the exhaust stream to create a fuel-rich mixture, the quantity of fuel being sufficient to react with the oxygen and reduce the NOx in said exhaust stream. The fuel-enriched stream is provided to an afterburner (18), and the fuel, NOx and available oxygen are reacted to provide a heated oxygen-depleted stream (20). The oxygen-depleted stream (20) is cooled in a heat exchanger (22). Conversion oxygen (29) is admixed with the cooled stream which is then passed over a catalyst bed (25) under overall reducing conditions. NO is converted to NO2 at the forward end of the bed, and the NO2 then reacts on the remainder of the bed with excess combustibles. Air is added to the resulting stream from the catalyst bed (25) to produce a cooled stream (24) having a stoichiometric excess of oxygen, and the cooled stream is passed over an oxidizing catalyst bed (26) to oxidize remaining combustibles. The resultant low NOx stream can then be provided for venting. |
