| 摘要 |
The invention relates to a method for reducing the NOx emission from a kiln plant for heat treatment of raw materials, in which kiln plant fuel can be fired in at least three different zones. In one of these at least three zones an amount c of fuel is burned, in a second of these zones an amount b of fuel is burned and to this second zone the NO containing exhaust gases from the other at least two zones are also fed. In the rest of these at least three zones an amount a of fuel is burned and at least a part of the raw materials are fed to these zones together with an oxygen containing gas. The total amount of fuel, b + a, burned in the second and in the last zones is determined by the need for treatment of the raw materials. When the kiln plant is used for manufacturing cement clinker, the heat treatment consists of preheating, calcining, sintering and cooling of the mineral raw materials. The invention seeks to provide a method by means of which a reduced NOx emission from a kiln plant is obtained, allowing, at the same time, utilization of fuels of low reactivity, such as petroleum coke, anthracite and other coals with a low gas content, in zones at a relatively low temperature. In accordance with the invention, this objective is accomplished in that the amounts of fuel, b and a, are adjusted in upward and downward direction until a minimum NO content is achieved in the exhaust gases from the zone to which the NO containing exhaust gases from all other firing zones are fed.
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