Pilot testing and numerical simulations of the multifuel burner for the cement kiln

Rotatory kilns fed with fossil fuels, which are widely used in cement industry, are responsible for significant CO2 emissions to atmosphere, increasing the stress on the environment. Substantial energy consumption, associated with the cement production process, leads to significant environmental and economical footprint in Europe and beyond, thus measures for reducing fossil fuel usage and decreasing an environmental impact are sought. One of the implemented measures is the substitution of the typical fossil fuels used in the kilns (coal or petcoke) by alternative fuels, such as biomass, RDF (refuse-derived fuel), sewage sludge or MSW (municipal solid waste). The objective is to reduce the greenhouse gas emissions, achieve the circular economy goals and decrease the production costs. This study presents the results of the pilot-scale tests (conducted in the 1 MW combustion facility at the Institute of Power Engineering), CFD simulations of both pilot-scale and full-scale burner for the cement rotary kiln. On the basis of the experimental data, a numerical investigations of the 1 MW pilot facility was made and validated. The numerical modelling, in a pilot-scale burner, was also intended to check the possibility to co-fire petcoke (as a base fuel) with alternative fuels such as MSW, biomass and hydrogen. Finally, the combustion in the industrial scale 75 MW cement rotary kiln burner was numerically analysed to analyse the conditions inside the reference cement installation and to propose a possible solutions to allow substitution of fossil fuels with RDF. The results showed that it is possible to co-fire a high shares of the alternative fuels in the rotary kiln without the negative effects on the combustion performance. It was also found, that the base fuel (petcoke) can be almost completely replaced with the alternative fuels such as RDF or biomass, while addition of the hydrogen to the fuel mixture can even improve the combustion characteristics.