Arraste de partículas finas em um leito fluidizado e eficiência de coleta de um ciclone dipleg

Abstract

The system with a fluidized bed and a cyclone dipleg as gas-solid separator is used in industry in unities of circulating fluidization. Some applications are: the fluid catalytic cracking, to produce gasoline and heating oil and the beds of combustion. The principal variables to be identified in the cited system are the flux of entrained particles in the bed and the collection efficiency of the cyclone. The present work had the objectives of studying the entrainment flux of seven fine particles (Geldart A and C) with three different superficial gas velocities in the bed and analyse the collection efficiency of the cyclone dipleg for all the conditions of operation. The experimental results of the two cases were compared to the predicted for models. Three kinds of glass spheres, three kinds os FCC (catalyst used in the fluid catalytic cracking) and one kind os phosphate powder were the used particles. The gas velocities in the bed were 0, 26, 0, 31 and 0, 36m/s, in these velocities the bed worked in the regime of fast fluidization, that is the one used in circulating systems. The particles were characterized and their minimum fluidization velocities were inferred. It was possible to observe that with the increasing of the gas velocity in the bed, the entrainment flux increases; for Geldart A particles, when the fraction of Geldart C solids is higher, the entrainment flux increases and for Geldart C materials, when there is a decrease in mean diameter, the entrainment flux is smaller. The cyclone is well dimensioned for the unit and presented maximum values of efficiencies for all the analysed cases.