This work deals with the power consumption and the fluid dynamics features of a model digester for biogas production by agricultural scraps fermentation. A combination of experimental techniques is adopted in order to obtain the full characterization of an industrial digester stirred by multiple impellers, which is scaled-down following the geometrical similarity criterion, under various impeller speeds and three liquid heights. A number of critical fluid dynamics characteristics of the reactor are identified: the velocity field is strongly dampened far from the impellers region, thus leading to wide stagnant zones; the shape of the discharge flows of the impellers and their interaction are significantly affected by the Reynolds number; under specific conditions, flow instabilities of wide amplitude take place; the power consumption is different from that of standard configurations and depends on the liquid level. Geometrical modifications are suggested for achieving better mixing and enhancing the overall process performances.

Fluid dynamics characterization of a stirred model bio-methanation digester

MONTANTE, GIUSEPPINA MARIA ROSA;PAGLIANTI, ALESSANDRO
2015

Abstract

This work deals with the power consumption and the fluid dynamics features of a model digester for biogas production by agricultural scraps fermentation. A combination of experimental techniques is adopted in order to obtain the full characterization of an industrial digester stirred by multiple impellers, which is scaled-down following the geometrical similarity criterion, under various impeller speeds and three liquid heights. A number of critical fluid dynamics characteristics of the reactor are identified: the velocity field is strongly dampened far from the impellers region, thus leading to wide stagnant zones; the shape of the discharge flows of the impellers and their interaction are significantly affected by the Reynolds number; under specific conditions, flow instabilities of wide amplitude take place; the power consumption is different from that of standard configurations and depends on the liquid level. Geometrical modifications are suggested for achieving better mixing and enhancing the overall process performances.
Giuseppina Montante;Alessandro Paglianti
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/430686
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