Temperature conditions in a 150 kW pilot rotary kiln: Impact of heating system and bed material

Other conference contribution, 2024

In an effort to address the significant greenhouse gas emissions from the cement industry, which constitutes 8% of global emissions, this research focuses on the temperature conditions in a 150 kW pilot rotary kiln, examining the impact of different heating systems and bed materials through an in-depth study of Kiln Zero. The investigation focuses on the thermal dynamics and efficiency of a prototype rotary kiln, examining the impact of alternative heat transfer systems and varying raw material mixes on kiln performance. Detailed empirical measurements, including wall temperatures, and radiative intensity, were obtained. A key aspect of this research is the characterization of an insulating coating layer within the kiln's interior. The thickness of this coating layer was challenging to measure directly due to high temperatures, so it was calculated theoretically. Estimations of the buildup layer's thickness were consistent with theoretical calculations, indicating its significant insulating effect. The inner and outer wall temperatures and radiative intensities of the kiln were measured for both heating settings for calcination, which increased when the heat source shifted from propane to electricity. To reach the clinkerization temperature, the propane setting had to be combined with pure oxygen, which resulted in an increased wall temperature and radiative intensity.