Patent ID: 6296820
Filing Date: 2001-10-02
Classification: B01D,B04C

Abstract:
In a combustion process, a method of reducing NO.sub.x emissions from plants, by providing a dwell chamber in which NO.sub.x decomposition occurs substantially solely as a result of the time the emissions dwell in the dwell chamber in a temperature range from about 450 degrees Celsius to 790 degrees Celsius, said method comprising the steps of:forming NO.sub.x in a combustion process to form an exhaust gas;transferring exhaust gas from the combustion process to a dwell chamber to increase the dwell time of the exhaust gas;at least partially decomposing the NO.sub.x in the exhaust gas in the dwell chamber substantially solely as a result of the time the emissions dwell in the dwell chamber in a temperature range from about 450 degrees Celsius to 790 degrees Celsius in an oxidizing atmosphere;expelling the exhaust gas from the dwell chamber;wherein said step of at least partially decomposing the NO.sub.x in the exhaust gas in the dwell chamber in a temperature range from about 450 degrees Celsius and 790 degrees Celsius in an oxidizing atmosphere further comprises maintaining the temperature of the exhaust gas in the dwell chamber between about 450 degrees Celsius and 790 degrees Celsius to permit the NO.sub.x to decompose;wherein said step of forming NO.sub.x in a combustion process to form an exhaust gas further comprises forming NO.sub.x with a fuel-air ratio (Lambda) greater than about 1; anddecreasing the flow velocity between an entry to the dwell chamber and an exit of the dwell chamber to increase the dwell time of the exhaust gas in the dwell chamber.