Modelling and measurements of radiation in a 400kWth rotary kiln test furnace

Other conference contribution, 2015

This work is focused on the radiative heat transfer in rotary kilns used for iron ore production with the aim to obtain a better understanding of the radiation and peak flame temperatures. This was done by performing measurements in a cylindrical, refractory lined, 400 kWth down scaled model of a rotary kiln and evaluating the results with a detailed radiation model. A mixture of coal and torrefied biomass was used as fuel in the experiments. Radiative intensity, gas composition, temperature and particle concentration were measured along the diameter in the flame. The radiation model treats the furnace as an axisymmetric and infinitely long cylinder. The gas properties are calculated with a statistical narrow-band model while the particle properties are calculated with Mie theory. The radiative heat transfer, peak flame temperatures and the influence from different parameters using sensitivity analyses are studied. It is shown that the total radiation is dominated by the contribution of particles, hence the total radiation is sensitive to changes in the particle concentration and size distribution. It was also possible to estimate the peak flame temperatures, and conclude that more accurate temperature and particle measurements are needed in future work.