Estudo numérico (via CFX) e experimental da secagem de blocos cerâmicos

Abstract

Bearing in mind that Brazil, in addition to having an important industrial park in the ceramic sector, raw materials in abundance, a stable growth rate in the civil construction sector and also being one of the largest consumers of ceramic material in the world, leads us to realizing that this sector only depends on the quality of its product and the cost of its production, which directly depend on an efficient drying stage. Stage in which the energy demand is high and, generally, met by non-renewable energy sources, causing environmental impact through the emission of CO2. The present thesis aims at both the development of a numerical model for drying brick in an oven (via CFX) and the development of an ecological brick for industrial production. The experimental work from Nascimento (2002) was used to validate the numerical model developed in this thesis, which adopted the liquid diffusion model as mass transport between domains, as used by Araújo (2019) and Santos (2019). Thus, the determination by numerical model of the diffusivity in the brick at temperatures 60, 80 and 110°C was sought, as well as the determination of the parameters of the Arrhenius equation for the brickgreenhouse system. In this way, the mass and thermal behaviors are presented in graphic images, through numerical simulation, through their gradient fields and their kinetic curves in different drying times and temperatures. It is worth mentioning that the present model also portrayed the behavior of variables external to the brick, such as temperature and velocity of the hot air current that surrounds it, and when taking into account the surrounding conditions, the model makes the results closer to the real. The experimental part of the ecological brick production work was carried out in the laboratory of the Water Treatment Station (ETA), located in Piranhas (AL), which is operated by Companhia de Saneamento de Alagoas (CASAL). Aiming at greater sustainability in the production processes, not only of the industrial brick, but also of water treatment, an attempt was made to develop an ecological brick through the use of ETA sludge in the composition of the clayey mass, since this residue is rich in aluminum, capable of adding greater resistance to the brick, allowing it to meet NBR 16814, which stipulates the minimum resistance for an ecological brick. Thus, in an unprecedented way, a clean destination for this waste was made possible in the backlands of Alagoas, as well as the production of an ecological brick without the burning stage, thus reconciling the sustainable interests in common of the industrial sectors: sanitation and ceramics.