Fluidization of biomass: a correlation to assess the minimum fluidization velocity considering the influence of the sphericity factor

SAFFE, ALEJANDRA; SUÁREZ, SERGIO; REYES URRUTIA, ANDRÉS; ZAMBON, MARIANA ; RODRIGUEZ, ROSA; SORIA, JOSÉ; ECHEGARAY, MARCELO; MAZZA, GERMAN

PARTICULATE SCIENCE AND TECHNOLOGY

TAYLOR & FRANCIS INC

Lugar: Londres; Año: 2021 vol. 39 p. 1020 - 1040

0272-6351

Thispaper deals with the influence of different definitions for evaluating thesphericity factor on the prediction of minimum fluidization velocity (Umf)of different agro-industrial/forestry biomass residues and sand. Three biowastes(sawdust, grape marc, and grape stalk) and sand were characterized by sieving,and sphericity was calculated using images obtained by scanning electronmicroscopy (SEM). Two particle size populations (with mean diameters anddensity corresponding to B and D Geldart groups) were adopted for each biomass.As for sand, particles with a mean diameter of 0.33 mm were used. Tests werecarried out in a lab-scale fluidized bed. Bed pressure drop was measured as afunction of the superficial velocity of air at two different initial bedheights, for each type of biomass and mixtures with sand. Ratios of 0.50 and 0.75 (v/v) were used for mixtures.  For allcases, Umf values werecalculated experimentally and were compared against predicted values obtainedfrom Ergun´s equation and other correlations. It was found that the methodologyadopted for determining sphericity significantly influences the obtained valueof Umf. The lowest relative error between predicted andexperimental Umf values was obtained using Riley?s sphericitymethod. Finally, a new correlation for Umf was proposed.