Patent ID: 7435400
Filing Date: 2008-10-14
Classification: B01D,F23C,F23J,F23N,Y02A,Y02E

Abstract:
1. A method for complete combustion of a carbonaceous fuel, low volatile matter, low sulfur coal, in a primary combustion zone of a boiler or furnace operating at about 3000° F. gas temperature and near to or at stoichiometric condition of unity in order to increase combustion efficiency and nitrogen oxide, NO x , concentrations, while reducing carbon dioxide, CO 2 , and sulfur dioxide, SO 2 , concentrations in the primary combustion zone below levels attainable with more fuel rich combustion and higher sulfur coal, comprising: identifying a post-primary combustion zone within the boiler or furnace having gas temperatures between about 1700° F. to 2500° F.; injecting an aqueous urea or ammonia solution as dispersed air atomized droplets of varying diameters across a planar spray pattern perpendicular to gas flow direction for reducing NO if required to augment the aqueous urea or ammonia solution to achieve the reduction of the NO adjusting water concentration in the aqueous urea or ammonia solution to levels that are high enough to cool the gases to about 2100° F. to 2200° F. or below in order to enable urea or ammonia-NO