Influência da altura de um secador tipo leito fixo de alumina com reversão de escoamento do ar

Abstract

The drying process in industrial scale is a unit operation that demands large amounts of thermal energy. This process always needs to be done in an optimized way. Fixed beds are commonly found in the chemical industry as packed columns and have lots of practical applications. Even though the fixed bed drying process is used only in minor scales, knowing the mechanisms of this process could be useful to understand and extend the knowledge in other applications, such as solid drying in treadmill and prevent the dynamic behavior in storage silos, for example. In a way, thick fixed beds prevent mechanic shocks, because the particulate material don’t move, but can cause significative temperature and moisture gradients during the process. In the drying process, the products that are closer of the hot air entrance dry faster than the products that are on the top. This kind of unevenness can be a problem, depending on the application. An alternative to overcome this situation is to reverse the hot air flow in time to time, sometimes ascending, sometimes descending. The objective of this work was to show de influence of the dimensions of the fixed bed in the homogenous drying process of alumina using the air flow reversal technique. Numerical tests were made using a program in Matlab software, developed in the Particulate Systems area of the Chemical Engineering Department of UFSCar. By the analysis of the results of the simulations, this study intends to analyze what happens with the fixed bed when it gains or loses volume, changing the bed height.