A furnace that combusts fuel, such as coal, of a given minimum energy content to obtain a stated minimum amount of energy per unit of time is enabled to combust fuel having a lower energy content, while still obtaining at least the stated minimum energy generation rate, by replacing a small amount of the combustion air fed to the furnace by oxygen. The replacement of oxygen for combustion air also provides reduction in the generation of NOx.
This invention was made with United States Government support under Cooperative Agreement No. DE-FC26-00NT40756 awarded by the Department of Energy. The United States Government has certain rights in the invention.