External Heat Transfer Coefficient in Agitated Vessels Using a Radial Impeller and Vertical Tube Baffles

Abstract

There are several correlations used to predict the external heat transfer coefficient in tanks equipped with vertical tube baffles in batch operations, but little information concerning the external heat transfer coefficient in steady state operations. The objective of the present article is to experimentally determine a correlation of the external heat transfer coefficient based on the model proposed by Sieder and Tate (Ind. Eng. Chem. 1936, 1429–1435) in a steady flow rate in a vessel equipped with a radial impeller, turbine type, with six flat blades. The study was carried out in a 50 dm3 working capacity acrylic vessel, fitted with vertical tube baffles made of copper, in which water and sucrose solutions at mass concentrations of 20% and 50% were heated. Heating temperatures varied from 28 to 45 °C, whereas the rotations varied from 90 to 330 rpm. From the Nusselt, Reynolds, and Prandtl similarity parameters, a correlation was obtained which yielded excellent results of the observed data–a maximum deviation of 21% between the observed and predicted data for the external heat transfer coefficient. In addition, one could also observe that the radial impeller raises the heat transfer to as much as 70% compared to the axial impeller for the same study conditions.

Reaction Calorimetry and Scale-Up Considerations of Bromo- and Chloro-Boron Subphthalocyanine

“…For the large size, a 10× factor is used, resulting in a reactor size of 2000 L, and 1800 L fill for the reaction. An estimated heat transfer coefficient of 200 W/(m 2 K) and 600 W/(m 2 K) was assumed for the 200 and 2000 L, respectively, using values previously established for similar jacketed reactors. − It was also assumed that the only source of energy generation in the reactor was due to the reaction exotherm (e.g., no mixing driven temperature rise). Expected mass yields for the Br-BsubPc process at both reactor sizes were calculated assuming a 50% yield, which is consistent with the baseline process run at room temperature (25 °C).…”

Roteiro de projeto de chicana tubular vertical em tanques agitados com turbina Rushton / Project roadmap for vertical tubular baffle in agitated tanks with Rushton turbine

“…6 . O coeficiente de convecção interno é corrigido (ℎ 𝑖𝑜 ) em relação a área externa, pois o fenômeno de troca térmica ocorre entre a parede do tubo e o líquido agitado (Eq.…”