FLUIDIZATION OF BINARY MIXTURES OF COAL WITH SAND AND BIOMASS IN A BENCH SCALE REACTOR
Enzo S. Ocanha1; Hartur Kunzler Mainardi1; Fernando Almeida Santos2; Flávia Schwarz Franceschini Zinani1
1 Universidade do Vale do Rio dos Sinos; 2 Universidade Estadual do Rio Grande do Sul
Baixar PDF doi:10.20906/CPS/CBCM2017-0107
Resumo
Thermal energy conversion industries have been increasingly employing fluidized bed combustion technology. Fluidized beds are a good choice to burn low rank coals, biomass and fuels of high humidity, such as industrial and urban waste. The fluid dynamics of a fluidized bed provides valuable information for the design and operation of such system. However, the mathematical modeling of fluidization, even for homogeneous particles, is a complex subject. It comprises modeling the gas flow, the solids flow and the interaction of them. In the case of mixtures of particles with different physical properties, predicting fluid dynamics is a major challenge. It is common to rely on empirical correlations in order to obtain design parameters such as fluidization velocity and bed expansion rate. The objective of the present work is to investigate the fluidization behavior of blends of coal with two lignocellulosic biomasses and with an inert material. The fluidization velocities obtained experimentally were compared with predictions using correlations, and features such as segregation and agglomeration of clusters during the experiments have been studied. The materials employed in the blends with coal were sand and sugarcane bagasse and straw, in the following proportions: 20, 40, 60 and 80 percent in volume. Coal, sand and biomasses were analyzed for their particle size, mass density and apparent mass density, and biomasses for their proximate and ultimate elemental composition, heating value and thermogravimetric behavior (TGA). A bench scale reactor was employed to fluidize coal, sand, and blends of coal-sand and coal-biomasses. The fluidized bed was a cylindrical tube of 94 mm ID. The fluidization agent was compressed air at room temperature, injected through a mesh distributor at the bottom of the reactor. A differential pressure transmitter (Novus Huba 699) was employed to measure pressure drop along the fluidized bed, while the air flow rate was measured by a flow rate meter (IFM SD6050). The characterization showed t
Palavras-chave: Fluidization; Binary Mixtures; Biomass; Sand