Patent ID: 6210154
Filing Date: 2001-04-03
Classification: F27B,F27D,Y02P

Abstract:
A method of reducing the emission of nitrogen oxides from a mineral-burning process, which process comprises the steps of feeding mineral raw material into a rotary kiln where it is burnt, the rotary kiln being fired by the combustion therein of a first fuel in the presence of a first combustion-supporting gas, the method being characterised by the steps of passing the exhaust gas from the rotary kiln through a combustion zone and of introducing a second fuel, in the form of solid fuel elements, into the said combustion zone, the solid fuel elements being maintained with the said zone until at least 30% by weight of the volatile combustible content thereof has been removed from said fuel elements, the said combustion zone containing at least one region in which combustion of at least part of the volatile combustible component(s) of the second fuel occurs under sub-stoichiometric conditions.