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Improving the sustainability of cement clinker calcination process by assessing the heat loss through kiln shell and its influencing factors: A case study in China

Wu, Wei-Ning, Liu, Xiao-Yan, Hu, Zhou, Zhang, Rong, Lu, Xin-Yue
Journal of cleaner production 2019 v.224 pp. 132-141
case studies, cement, convection, energy efficiency, heat recovery, kilns, recycling, temperature, thermography, China
Cement clinker calcination in rotary kiln is an energy intensive process. Heat recovery from the kiln shell surface is a potential way to improve energy efficiency to make cement production cleaner and more sustainable. In this work, methods were proposed to assess the heat loss through the kiln shell and its influencing factors, using an industrial cement kiln in China as study case. By use of infrared thermography, the shell temperature and the heat loss through kiln shell were monitored for 19 days. Calculation shows that the daily heat loss through kiln shell in the calcination zone of the investigated kiln is about 140 GJ, and the heat losses by radiation and convection are comparable, accounting for 54% and 46%, respectively. Five main operating variables that greatly affect the heat loss are identified jointly by Random Forest and Pearson correlation coefficient. Results of this work will help company administrators create a strong awareness about improving energy efficiency of the kiln system, so that appropriate strategies are designed to reduce the heat loss through kiln shell. The work can also contribute to a better understanding of rotary kiln operation to reduce the heat loss. The work makes the cement clinker calcination process more sustainable by laying the foundation for recycling or reducing the waste heat loss through kiln shell.