Estudos fluidodinâmicos e de secagem de fertilizantes em diferentes tipos de secadores rotatórios

Abstract

Drying is an important process that a lot of products were submitted. However, this process is usually very energy-intense and has a large commercial impact on the cost of the final product. The conventional direct rotary dryer consists of equipment widely used in industrial area due to advantages such as, a high processing capacity of a wide variety of materials. This dryer is commonly used to dry and process granular materials, and has application across a wide range of industries like the fertilizer industry. In the Triangulo Mineiro region and Alto Paranaiba, where is also located the city of Uberlândia - MG, the fertilizer industry exemplifies the use this equipment for removing moisture from the final product. The drum of the rotary cascade dryer is equipped with lifting flights. Many potential benefits can be obtained through a greater understanding of the rotary drying process. One such benefit could be energy savings, whose magnitude can be determined by estimating the energy cost of drying in the particleboard industry. In order to improve drying efficacy, another version of the rotary dryer, known as the ―rotoaerated‖ dryer, was evaluated by Lisboa (2007) and Arruda (2008). the roto-aerated version provides better mass and energy transfer between the hot air and the solids than the conventional countercurrent rotary dryer. The main characteristic of the rotoaerated dryer is its aerated system, which consists of a central pipe (encased in the drum), from which a series of mini-pipes carry hot air directly to the particle bed flowing at the bottom of the drum (without flights). The present work analyzes the drying of granulated fertilizers in a rotoaerated dryer. This work has tested several positions and different diameters of mini pipes. Due to finding the optimum drying performance presented by rotoaerado dryer, the present work aims to study the drying of SSPG fertilizer granules in rotoaerated dryers with different configurations that have not studied, varying the diameter, the provision and quantity of mini pipes. The performance of rotary dryers configurations, were compared based on experimental results. The results of this study have values of loading, residence time, drying rate, and the difference between rotoaerated dryer and concurrent and countercurrent rotary dryers, working under the same operating conditions. It was also found that while the configurations evaluated in previous studies showed results of the drying rate four times higher compared to conventional version, in this work it was possible to find configurations with superior results reaching a drying rate up to 18 times higher compared the conventional version. This study also study different parameters in a Discret Element Method (DEM) simulation method with a linear model.