Estudo experimental da fluidização gasosa de leito de partículas de sílica e casca de castanha de caju

Abstract

The use of solid biomass (shell) arising from the agriprocessing of cashew nut is still something to be solved due to the non-availability of appropriate technologies for heat or energy generation in environmentally sustainable manner. The practice of the direct burning on boilers and industrial furnaces has resulted in pollutant emissions, among them: particulate matter, carbon monoxide, nitrogen oxides, and others. Therefore, an experimental study of gaseous fluidization of binary mixtures, constituted of pellets of crushed biomass (cashew nut) and an inert porous material (silicon), was carried out to adequately interpret fluidynamic phenomena present in the bed. The goal was to identify the influence factors and design parameters for the development of high-efficiency low-emission fluidized bed burners. The experimental apparatus employed in this study consists of a research setup constituted of 3 acrylic tubes with different diameters, filled with sand and cashew nut particles, in averaged concentration ratios of 2.9 and 3.9, respectively, with granulometries specified according to the Geldart’s standard. The fluidynamic performance of the bed was analyzed, featuring the fenomena present in the process through pressure measurement at points uniformly distributed along the entire bed. The influence of the main operation parameters: equivalence ratio; minimum fluidization velocity; bubbling bed velocity and biomass diffusion velocity; were the study object. The experimental results have pointed out some design relations between the length and the cross section of bed at the approximate ratio of 65:1; and between the minimum biomass diffusion velocity and the air flow rate in this condition at the ratio of 1: 134, approximately.