Eventos Anais de eventos
ENCIT 2020
18th Brazilian Congress of Thermal Sciences and Engineering
STUDY OF ZEOTROPIC MIXTURES FOR COGENERATION IN THE CEMENT INDUSTRY
Submission Author:
Thais Assis , MG
Co-Authors:
Thais Assis, Felipe Raul Ponce Arrieta
Presenter: Felipe Raul Ponce Arrieta
doi://10.26678/ABCM.ENCIT2020.CIT20-0005
Abstract
This work aimed to study energy cogeneration through the Regenerative Organic Rankine Cycle (ORC) for waste heat recovery in cement industry using zeotropic mixtures as working fluid. In addition, an ideal simple ORC was also modeled in order to choose the molar fraction of each mixture and their performance in the cycle. After modeling the cycles, some operating parameters of the ORCs were optimized with the maximization of the net power as an objective function. The zeotropic mixtures properties were used from the REFPROP software database, the models were calculated using the Engineering Equation Solver (EES) software and the optimizations, performed in the same program, employed the conjugated direction method. The results of the ideal ORC showed that the MM/MDM mixture, at a molar fraction of 0,1/0,9, obtained the greatest power production. However, this mixture had a lower pressure at the condenser outlet than the atmospheric pressure, so it would be necessary to make a vacuum in the condenser and the total cost of the system would increase, therefore, this mixture was rejected from the study. The mixtures selected for the study were R227ea/R245fa, MDM/R134a, MD2M/R134a and D4/R134a, the molar fraction proportions chosen were 0,1/0,9, 0,44/0,56, 0,345/0,655 and 0,378/0,622, respectively. In the optimizations results, it was found that the average superiority of the regenerative cycle operating with the R227ea/R245fa mixture, in terms of net power, was around 31.9%, 31.8% and 49.0% when comparing with the other mixtures MDM/R134a, MD2M/R134a and D4/R134a, in that order. From an economic perspective, the highest cost for the production of electricity among the mixtures studied was 41.32% lower than the electricity sale price practiced by the local energy concessionaire.
Keywords
Regenerative Organic Rankine cycle, zeotropic mixtures, conjugate direction method
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