The most energy demanding process in the cement industry is clinker production, carried out in a rotary kiln. Thus, rotary kiln energetic and exergetic analyses are useful tools to reach cement production process improvements. Energetic analysis is based on the first law of thermodynamics and allows one to calculate the heat uses and losses. On the other hand, exergetic analysis is based on a combination of the First and Second Laws of Thermodynamics and allows quantifying process irreversibilities. Some rotary kiln exergy analyses neglect the mass flows chemical exergy in the exergetic analysis, considering only the fuel chemical exergy. In this work, chemical exergy impact on this analysis was evaluated. Pre-calcination effect was also studied. Rotary kiln classical and modern exergetic efficiency considering all the chemical exergy contributions were 55.5% and 41.8%, respectively, while considering just the fuel chemical exergy were 38.2% and 22.6%, respectively. The results showed that it is inadequate to neglect the mass flows chemical exergy, since their contribution in the exergetic analysis was relevant. Furthermore, it was observed that the method adopted in the process efficiency evaluation affects the system interpretation. Considering the modern exergetic efficiency, results showed that, the higher the pre-calcination, the higher rotary kiln efficiency.

中文翻译：

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实际熟料回转窑火用分析中的化学火用影响

水泥工业中能耗最高的过程是在回转窑中进行的熟料生产。因此，回转窑能量和火用分析是实现水泥生产过程改进的有用工具。能量分析基于热力学第一定律，可以计算热量的使用和损失。另一方面，热力学分析基于热力学第一定律和第二定律的结合，可以量化过程的不可逆性。一些回转窑火用分析在火用分析中忽略了质量流化学火用，只考虑了燃料化学火用。在这项工作中，评估了化学火用对该分析的影响。还研究了预煅烧效果。考虑所有化学火用贡献的回转窑经典和现代火用效率分别为 55.5% 和 41.8%，而仅考虑燃料化学火用的分别为 38.2% 和 22.6%。结果表明，忽略质量流化学火用是不够的，因为它们在火用分析中的贡献是相关的。此外，据观察，在过程效率评估中采用的方法会影响系统解释。考虑到现代火用效率，结果表明，预煅烧越高，回转窑效率越高。因为他们在有效分析中的贡献是相关的。此外，据观察，在过程效率评估中采用的方法会影响系统解释。考虑到现代火用效率，结果表明，预煅烧越高，回转窑效率越高。因为他们在有效分析中的贡献是相关的。此外，据观察，在过程效率评估中采用的方法会影响系统解释。考虑到现代火用效率，结果表明，预煅烧越高，回转窑效率越高。