Ponencia
Alternating Field Electronanofluidization
Autor/es | Espin, M. J.
Valverde Millán, José Manuel Sánchez Quintanilla, Miguel Angel Castellanos, Antonio |
Departamento | Universidad de Sevilla. Departamento de Electrónica y Electromagnetismo |
Fecha de publicación | 2009 |
Fecha de depósito | 2020-12-01 |
Publicado en |
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ISBN/ISSN | 0094-243X (impreso) 1551-7616 (electrónico) |
Resumen | The use of fluidized beds to remove submicron particles from gases has been investigated since 1949. High efficiency removal was achieved in the 1970’s by imposing an electric field on a fluidized bed of semi-insulating ... The use of fluidized beds to remove submicron particles from gases has been investigated since 1949. High efficiency removal was achieved in the 1970’s by imposing an electric field on a fluidized bed of semi-insulating granules that were able to collect the charged pollutant entrained in the fluidizing gas. In spite of their extended use nowadays, the collection efficiency of electrofluidized beds (EFB) is still hindered by gas bypassing associated to gas bubbling and the consequent requirement of too high gas flow and pressure drop. In this paper we report on the electromechanical behavior of an EFB of insulating nanoparticles. When fluidized by gas, these nanoparticles form extremely porous light agglomerates of size of the order of hundreds of microns that allow for a highly expanded nonbubbling fluidized state at reduced gas flow. It is found that fluidization uniformity and bed expansion are additionally enhanced by an imposed AC electric field for field oscillation frequencies of several tens of hertzs and field strengths of the order of 1 kV/cm. For oscillation frequencies of the order of hertzs, or smaller, bed expansion is hindered due to electrophoretic deposition of the agglomerates onto the vessel walls, whereas for oscillation frequencies of the order of kilohertzs, or larger, electrophoresis is nullified and bed expansion is not affected. According to a proposed model, the size of nanoparticle agglomerates stems from the balance between shear, which depends on field strength, and van der Waals forces. The optimum field strength for enhancing bed expansion produces an electric force on the agglomerates similar to their weight force, while the oscillation velocity of the agglomerates is similar to the gas velocity. |
Agencias financiadoras | Ministerio de Ciencia y Tecnología (MCYT). España Junta de Andalucía |
Identificador del proyecto | FIS2006-03645
FQM 421 |
Cita | Espin, M.J., Valverde Millán, J.M., Sánchez Quintanilla, M.A. y Castellanos, A. (2009). Alternating Field Electronanofluidization. En 6th International Conference on the Micromechanics of Granular Media (97-100), Golden, Colorado, (Estados Unidos): American Institute of Physics. |
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