Desenvolvimento de um sistema de secagem para beneficiamento de caulim usando energia solar.

Abstract

The motivation of this work was the study of energy efficiency in companies that work in the area of kaolin processing in the region of the Pegmatitic Province of Borborema (PPB), the diagnosis pointed out that firewood was the most used energy source during the kaolin drying process. . The objective of this thesis was to develop a drying system for the processing of kaolin, using solar energy as the predominant energy source to minimize the use of firewood during the drying process. The methodology used consisted of carrying out the diagnosis from visits to the main kaolin processing companies in the PPB region, followed by the characterization of data on the solar resource and ambient air available in the region, in this case, the energy source and the working fluid, used in the drying process. A partnership was carried out with a company in the region, INCOMGEL, located in the city of Assunção - PB, where several experiments were carried out, and which welcomed the proposals for modifications, aiming to increase the efficiency of the kaolin drying process. At the same time, experiments were carried out at the Experimental Laboratory of Thermal Machines (LEMT) of the Federal University of Campina Grande (UFCG). In this work, the results of four experiments were presented, testing three different solar drying systems: the first, with a polycarbonate cover; the second, with a polypropylene covering and the third, a natural solar drying system, without covering, which allowed to observe which was the most suitable for drying kaolin and also to obtain the kaolin drying kinetics curve, as well as the thermal efficiency of each system. The results obtained showed that the system with the polycarbonate cover was the most efficient, with an average yield of 30.87%. As for the incidence of solar irradiation, the average recorded in the summer period was 974.01 W/m2, and in winter it was 604.51 W/m2. For ambient air, the average temperature recorded in the summer was 33ºC, the average relative humidity was 56%, the average air speed was 2.0 m/s. This information was used to propose changes in the architecture, positioning and layout of the new sheds, including height, positioning and type of coverage. An electric power generation system was proposed and dimensioned, using photovoltaic solar panels to be used to drive industrial fans and blowers that contributed, through forced convection of drying air, to reduce the drying time of kaolin. The main conclusions showed that the combination of solar thermal and photovoltaic energy contributed to make the kaolin drying process more efficient. The company object of the study installed 750 m2 of solar panels, making it self-sufficient in the production of electrical energy used in its production process, becoming a management model in the area of energy efficiency in the region