| 摘要 |
The proposed process for the thermal treatment of fine granular material, especially for producing cement clinker from raw material is carried out in stages, by means of a preheating stage, a calcining stage, a sintering stage and a cooling stage, heat being supplied from any type of fuel, i.e. heat is supplied from gaseous, liquid or solid fuels both in the calcining stage and in the sintering stage. In a process of this type it is proposed to subdivide the calcining stage into a precalcining stage and into an after-calcining stage, the precalcining stage being heated by the off-gases of the sintering stage and the after-calcining stage being heated by fuel combustion of the gaseous, liquid or solid fuels by means of air. The hot off-gases of the sintering stage are admixed with a reductant and/or a catalyst for the thermal-chemical reaction with nitrose constituents contained in the off-gases, the admixture of the reductant and/or the catalyst being effected between the sintering stage and the precalcining stage. By means of thermal equilibrium decomposition, the nitrogen oxides contained in the off-gases of the sintering stage are considerably reduced, and at the same time said off-gases can be employed, in order to utilise their full exergy, in the preheating and precalcination of the finely granular material employed, for example of the cement raw materials.
|
