Esposito, Martina (2018) ELECTROSTATIC SCRUBBING OF SUBMICRON PARTICLES: EXPERIMENTAL AND MODELING. [Tesi di dottorato]

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Item Type: Tesi di dottorato
Lingua: English
Title: ELECTROSTATIC SCRUBBING OF SUBMICRON PARTICLES: EXPERIMENTAL AND MODELING
Creators:
CreatorsEmail
Esposito, Martinamartina.esposito@unina.it
Date: 11 December 2018
Number of Pages: 108
Institution: Università degli Studi di Napoli Federico II
Department: Ingegneria Chimica, dei Materiali e della Produzione Industriale
Dottorato: Ingegneria dei prodotti e dei processi industriali
Ciclo di dottorato: 31
Coordinatore del Corso di dottorato:
nomeemail
Mensitieri, Giuseppemensitie@unina.it
Tutor:
nomeemail
Lancia, AmedeoUNSPECIFIED
Di Natale, FrancescoUNSPECIFIED
Giavazzi, MatteoUNSPECIFIED
Date: 11 December 2018
Number of Pages: 108
Uncontrolled Keywords: Wet Electrostatic Scrubber, particle charging model, submicron particle capture
Settori scientifico-disciplinari del MIUR: Area 09 - Ingegneria industriale e dell'informazione > ING-IND/25 - Impianti chimici
Date Deposited: 07 Jan 2019 23:44
Last Modified: 18 Jun 2020 05:15
URI: http://www.fedoa.unina.it/id/eprint/12629

Abstract

This work contributes to the development of the technology of Wet Electrostatic Scrubbing (WES) at industrial scale by improving the current knowledge on corona charger unit design and designing, by building and setting up a pilot scale WES for specific industrial applications. This work was developed jointly by the Department of Chemical, Material and Industrial Production Engineering of the University of Naples Federico II” and the Ecology Division of the Boldrocchi s.r.l. . The Wet Electrostatic Scrubber is an upgrade of a conventional wet scrubber: it was proved that the electric forces are the main responsible for particle capture, more than the other physical phenomena that might be present in the scrubber. Therefore, the first topic covered by the study was the assessment of design criteria to scale up corona charger for particle charging. To understand the actual particle charge distribution of an ensemble of particles entering a corona device, several parameters have to be defined: particles residence time, local electric field and ion concentration, particle shape and composition. These parameters are generally considered on their mean value, but this approach is not adequate for predicting particle charges for a more complex system. For this reason, using the simulation program Ansys Fluent to gain some information concerning particle behavior in the reactor, two different particle charging models will be compared to experimental data. To provide a reliable assessment of particle charge, we developed a particle capture model in a WES unit coupling the particle capture model with the results of a dedicated computational Fluid dynamic analysis performed using Ansys Fluent. The model was used to describe the experimental data obtained by our research group in a smaller WES pilot tested in several conditions during the EFP7 DEECON project. In particular, this model includes a dedicated assessment of droplets size and charge distribution, which can be achieved properly only by experimental data and the relevant fluid dynamic parameters as gas residence time distribution, droplets spatial distribution and gas-droplets relative velocities, which are evaluated through the computational program Ansys Fluent (explained in Chapter 3 in detail). Averaged values of particle charges were determined using theoretical models and mean values of electric field, ion concentration and residence time in the pilot scale corona charger. This predictive model was applied to the case study and compared with the experimental data. In order to overcome the limited knowledge on particle charging, a reversed approach to data analysis was proposed. In this case, the data on particle capture in the WES were used to calculate the charge deposited on the particles and the achieved data were considered in terms of total aerosol current, applied voltage and particle size. These information were used to define design and operating conditions for the pilot WES system (operating at gas flow rates ranging from 5500 to 10.000 Nm3/h) build and operated at the Boldrocchi factory in Biassono (MB, Italy). The pilot scale system was operated in several conditions using reference Arizona test dust particles. The experimental data demonstrated that the WES units are able to achieve particle removal efficiencies higher than 90% in number, for particles from 150 to 800 nm, with results consistent with the design specifications.

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