Cement applications
Concepts for calciners.
Task
The calciner is installed under the lowest cyclone stage. In this plant section, the raw meal is calcined (deacidified) by up to about 95 %. The energy input required by this stage (about 60 % of the plantʻs overall heating demand) is provided by means of special calciner burners, which can be operated with primary as well as secondary fuels.
The tertiary air duct is connected to the calciner.
By supplying the tertiary air in a special manner, it is possible to achieve a partially staged combustion that helps to reduce nitrogen oxide emission.
Demands (hot section):
Due to the varying use of alternative and regular fuels in the calciner burners, higher demands are placed on the installed refractory materials. High refractoriness and thermochemical resistance are the main requirements placed on the selected refractory wear linings. Hereby, the addition of SiC as well as zirconium oxide in the refractory materials increases the liningʻs wear resistance.
Demands (upper section):
In the upper calciner stages, the process temperatures drop to 850 ... 900 °C. The corresponding regions are divided into the upflow part of the calciner, the hot gas deflection, and the downflow part.
The thermochemical conditions in these regions are the basis for selecting refractory materials with specifically adapted alumina contents.
The calciner is installed under the lowest cyclone stage. In this plant section, the raw meal is calcined (deacidified) by up to about 95 %. The energy input required by this stage (about 60 % of the plantʻs overall heating demand) is provided by means of special calciner burners, which can be operated with primary as well as secondary fuels.
The tertiary air duct is connected to the calciner.
By supplying the tertiary air in a special manner, it is possible to achieve a partially staged combustion that helps to reduce nitrogen oxide emission.
Demands (hot section):
Due to the varying use of alternative and regular fuels in the calciner burners, higher demands are placed on the installed refractory materials. High refractoriness and thermochemical resistance are the main requirements placed on the selected refractory wear linings. Hereby, the addition of SiC as well as zirconium oxide in the refractory materials increases the liningʻs wear resistance.
Demands (upper section):
In the upper calciner stages, the process temperatures drop to 850 ... 900 °C. The corresponding regions are divided into the upflow part of the calciner, the hot gas deflection, and the downflow part.
The thermochemical conditions in these regions are the basis for selecting refractory materials with specifically adapted alumina contents.
