Oxy-fuel combustion of Refuse Derived Fuels (RDF) under cement kiln conditions

The objective of the Oxyflame project T1 is to transfer and extend the knowledge gained in the CRC Transregio 129 Oxyflame for power plants to the cement production process. In modern cement plants, pulverized coal is more and more replaced by low-cost waste-based refuse-derived fuel (RDF). The particles in this fuel are in the centimetre-range and their physical and chemical properties are very heterogeneous. In addition, oxygen concentrations in future oxy-fuel cement plants are significantly higher than in power plants. Therefore, the required extension of the models and experimental database already generated within the Oxyflame project is tackled by the three project partners, WSA, LEAT (Ruhr-Universität Bochum) and thyssenkrupp Industrial Solutions.

At the WSA, the modelling of the reaction kinetics as well as the radiative heat transfer are addressed. The fluidized bed reactor developed in the Oxyflame project A1 is used to derive data for the development of kinetic models for pyrolysis, gasification and char burnout. For the description of particle radiation, the models derived by the Oxyflame project C4 serve as a starting point. In order to account for the different sizes and compositions of RDF fractions compared to coal or biomass, the particle radiation is studied with numerical simulations to expand the current model to the new fuel.