Análise exergética avançada e otimização do processo de produção de clínquer em uma unidade de piroprocessamento

Abstract

Due to the high energy demand related to its production, and the global importance of this material, the study of the optimization of the cement production process is greatly relevant. The clinker production process has undergone important evolutions over the years to allow greater operational efficiency and the use of alternative fuel. This study intends to continue the work of reference developed in the same department and evaluate, through a thermodynamic analysis of exergy, advanced exergy and cost, the real impact of the use of these materials and the balance point between an efficient process and low production cost. To this end, the algorithm developed in the previous study was adapted to a new pyroprocessing unit. Real process data was collected in a plant during a 48h interval of stable operation and used for the analysis. The exergy efficiency of the analyzed operation was found to be 38,8%. The avoidable exergy destruction corresponded to 29,0% of the process destroyed exergy and it was possible to verify that the combustion temperature, excess air, gas and solid streams separation efficiency at the cyclones and the efficiency of the heat exchange in the cooler were important sources of exergy destruction that van be improved by means of process adjustments and technology improvements. The optimization allowed the identification of the operation with 65% thermal split to the calciner, 60% thermal substitution by alternative fuels, which consists fully of blended residue, and the exclusive use of petcoke as a conventional fuel as the optimal point regarding exergy efficiency. Cost optimization results in the same conditions for thermal split and alternative fuel usage but prioritizes the exclusive use of coal as conventional fuel. While the gain on exergy efficiency is lower compared to the optimization of this parameter, the cost optimization still resulted in an operation with higher exergy efficiency compared to the actual operation conditions.