Flagiello, Domenico (2020) Enhanced Seawater Scrubbing for flue-gas Cleaning. [Tesi di dottorato]


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Item Type: Tesi di dottorato
Lingua: English
Title: Enhanced Seawater Scrubbing for flue-gas Cleaning
Flagiello, Domenicodomenico.flagiello@unina.it
Date: 13 March 2020
Number of Pages: 226
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: 32
Coordinatore del Corso di dottorato:
Mensitieri, Giuseppegiuseppe.mensitieri@unina.it
Di Natale, FrancescoUNSPECIFIED
Erto, AlessandroUNSPECIFIED
Date: 13 March 2020
Number of Pages: 226
Uncontrolled Keywords: Flue-gas Cleaning; Seawater Scrubbers; Wet-Oxidative Scrubbing
Settori scientifico-disciplinari del MIUR: Area 09 - Ingegneria industriale e dell'informazione > ING-IND/25 - Impianti chimici
Additional Information: The Ph.D. thesis has been revised by: -Alessandro Paglianti, Professor at University of Bologna “ALMA MATER STUDIORUM”, Italy - Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali; -Dino Musmarra, Professor at University of Campania “Luigi Vanvitelli”, Italy - Dipartimento di Ingegneria Civile, Design, Edilizia e Ambiente; -Kent Salo, Senior Lecturer at Chalmers University of Technology, Göteborg, Sweden - Department of Mechanics and Maritime Sciences.
Date Deposited: 22 Mar 2020 23:38
Last Modified: 10 Nov 2021 10:00
URI: http://www.fedoa.unina.it/id/eprint/13064


This thesis work is focused on the development of new seawater-based scrubbing process for flue-gas cleaning, to be applied to both land-based industrial and power generation plants and to maritime shipping. Seawater scrubbing is receiving a growing attention mostly thanks to the diffusion of marine scrubbers for desulphurization of IFO fueled Marine Diesel Engines exhaust. The process is a viable option also for coastal infrastructures where seawater is abundant and it is funded on the exploitation of seawater alkalinity, which provides a valid and cost-effective sorbent for SO2. Seawater scrubbing can be improved by using caustic soda or other less common additives. Among them, oxidative reactants such as sodium chlorite (NaClO2), hydrogen peroxide (H2O2), ferrous-EDTA (Fe(II)-EDTA), sodium persulfate (Na2S2O8) or potassium ferrate (K2FeO4) have been suggested. This work adopts experimental and modelling methodologies to investigate the seawater scrubbing with caustic soda and sodium chlorite addition for the treatment of model flue gases as those coming from real marine diesel engines and coal/oil combustion plants. The work provides an analysis of SO2 solubility in the different water-based absorbing solutions and the estimation of the absorption efficiency of SO2 in packed and spray columns. The experiments are ruled out to define the optimal operating conditions for industrial and marine applications and to interpret how chemical reactions improve the mass transfer rate. The experimental campaign is supported by a dedicated modelling analysis accounting for equilibria, mass transfer and pressure drops in a unique framework, which is a valuable tool for the design of large scales applications. As a real case application, a comparison between spray and packed towers for a realistic marine engines is carried out, demonstrating that the packed tower can be a valid and cost effective solution, thanks to the far lower size and weight, which overcome the additional cost of packing. Finally, the effects of seawater-based scrubbing on the quality of the exhaust scrubbing solution are analyzed, for the possible capture of other gas pollutants. To this aim, a critical analysis of the properties of scrubber wash water in terms of heavy metals and organics is carried out. Test on real marine diesel engines shows that the emissions of heavy metals and organic compounds are in line with the current EU regulations on wash water discharge in natural water bodies and mostly of the analytes comply with the 2016/39/EU amendment of the Water Framework Directive. Finally, in order to further extend the field of investigation, the effect on other gaseous pollutants such as NOx of sodium chlorite seawater scrubbing is analyzed. Experimental evidences shows that sodium chlorite solutions provides a valuable removal of NOx compounds, opening to the possibility of a joint de-SOx/de-NOx process that is particularly advantageous for marine applications. In particular, the capture of NOx was promoted by the presence of SO2 in the exhausted gas and a complete removal can be achieved without any competitive effect. This was due to particular oxidation mechanisms occurring under acidic conditions arising during the absorption process.


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