Increasing energy efficiency and substitution rates in the clinker burning process by drying and grinding alternative fuels

Increasing energy efficiency and substitution rates in the clinker burning process by drying and grinding alternative fuels

When producing cement, a considerable amount of the thermal energy is required for burn-ing the cement clinker in rotary kilns. Today, alternative fuels are being used alongside fossil fuels as a substitute for the latter. Cement manufacturers are striving to increase the propor-tion of alternative fuels in order to stabilise and improve their competition situation. However, increasing use of alternative fuels means that the fuels must be of uniform quality; for exam-ple, the moisture content and particle size may only vary within certain limits. This is even more important, when the fuels are used in the main fining.

This research project aimed to first investigate the extent to which relatively inhomogeneous moist and coarse alternative fuels can be added into the kiln unprocessed. In the following the focus was on studying in what way it is technically and financially feasible to render these fuels usable by means of external drying, comminution and homogenization in the cement works, to increase the substitution rate. The benefit of the respective drying and grinding systems needs to be determined and then compared with the expense and effort involved. In order to achive this several operational trials in cement works have been conducted and a cost-effectiveness study has been prepared.

Supported by

The IGF project 18589 N of VDZ gGmbH was supported by the AiF within the framework of Industrial Collective Research (IGF) of the Federal Ministry of Economic Affairs and Energy on the basis of a decision of the German Bundestag.