Impact of thermal coatings on the optimization of an industrial furnace

Reference	Presenter	Authors (Institution)	Abstract
14-065	Pedro Ivo Batistel Galiote Brossi Pelissari	de Meo, C.E.(Universidade Federal de São Carlos); Pandolfelli, V.C.(Universidade Federal de São Carlos); Sako, E.Y.(Federal University of Sao Carlos); Pelissari, P.B.(Universidade Federal de São Carlos); Béttega, R.(Universidade Federal de São Carlos);	Industrial furnaces for sintering refractories operates at temperatures where thermal radiation reaches 95% of the entire heat exchanged. Controlling thermal radiation can be done through tailoring a refractory surface thermotical properties with specific coatings that are able to extinguish incoming radiation. This process is controlled by absorption and scattering coefficients used on, respectively, high emissivity and high reflectance coatings. Choosing between both possibilities is complex and not intuitive as industrial furnaces present many features. One possibility to overcome this issue is through numerical simulation where different physical phenomena can be considered while evaluating the thermal state of a furnace with complex geometry. Several published works in latest years attempted to evaluate energy gains in industrial furnaces due to introduction of high emissivity coatings, but a few have been published on the high reflectance possibility. In the present research, a case study of an industrial furnace was computationally simulated using a commercial software (Ansys Fluent) coupling the radiative transfer equation, Navier-Stokes and energy equation. The focus is understanding how different thermotical properties of materials impact the thermal state of the industrial furnace under consideration. The burners combustion was simulated using eddy dissipation model to obtain the reaction rates, a standart k-? model for the turbulent flow and discrete ordinate method to discretize the radiative transfer equation into a set of differentials equations considering 32 nonoverlapping directions. A series of simulations were performed testing distinct positions where thermal coatings can be applied. The maximum fuel economy was possible when both high emissivity and high reflectivity were used in strategic positions. The experimental results will be shown to corroborate the predictions provided by the numerical simulation tool.
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