A boiler apparatus having a furnace and a plurality of heat exchanger stages disposed in a channel for the combustion gas discharged from the furnace. The boiler apparatus is equipped with a denitrator which utilizes a catalyst and which is disposed in the optimum reaction temperature region for the...http://www.google.es/patents/US4160009?utm_source=gb-gplus-sharePatente US4160009 - Boiler apparatus containing denitrator
