Cenosphere formation from heavy fuel oil: a numerical analysis accounting for the balance between porous shells and internal pressure

Handle URI:
http://hdl.handle.net/10754/596924
Title:
Cenosphere formation from heavy fuel oil: a numerical analysis accounting for the balance between porous shells and internal pressure
Authors:
Vanteru, Mahendra Reddy ( 0000-0002-1651-6357 ) ; Rahman, Mustafa M.; Gandi, Appala; Elbaz, Ayman M.; Schrecengost, Robert A.; Roberts, William L. ( 0000-0003-1999-2831 )
Abstract:
Heavy fuel oil (HFO) as a fuel in industrial and power generation plants ensures the availability of energy at economy. Coke and cenosphere emissions from HFO combustion need to be controlled by particulate control equipment such as electrostatic precipitators, and collection effectiveness is impacted by the properties of these particulates. The cenosphere formation is a function of HFO composition, which varies depending on the source of the HFO. Numerical modelling of the cenosphere formation mechanism presented in this paper is an economical method of characterising cenosphere formation potential for HFO in comparison to experimental analysis of individual HFO samples, leading to better control and collection. In the present work, a novel numerical model is developed for understanding the global cenosphere formation mechanism. The critical diameter of the cenosphere is modelled based on the balance between two pressures developed in an HFO droplet. First is the pressure (Prpf) developed at the interface of the liquid surface and the inner surface of the accumulated coke due to the flow restriction of volatile components from the interior of the droplet. Second is the pressure due to the outer shell strength (PrC) gained from van der Walls energy of the coke layers and surface energy. In this present study it is considered that when PrC ≥ Prpf the outer shell starts to harden. The internal motion in the shell layer ceases and the outer diameter (DSOut) of the shell is then fixed. The entire process of cenosphere formation in this study is analysed in three phases: regression, shell formation and hardening, and post shell hardening. Variations in pressures during shell formation are analysed. Shell (cenosphere) dimensions are evaluated at the completion of droplet evaporation. The rate of fuel evaporation, rate of coke formation and coke accumulation are analysed. The model predicts shell outer diameters of 650, 860 and 1040 µm, and inner diameters are 360, 410 and 430 µm respectively, for 700, 900 and 1100 µm HFO droplets. The present numerical model is validated with experimental results available from the literature. Total variation between computational and experimental results is in the range of 3–7%.
KAUST Department:
Clean Combustion Research Center; Mechanical Engineering Program; Physical Sciences and Engineering (PSE) Division; Computational Physics and Materials Science (CPMS)
Citation:
Cenosphere formation from heavy fuel oil: a numerical analysis accounting for the balance between porous shells and internal pressure 2016, 20 (1):154 Combustion Theory and Modelling
Publisher:
Informa UK Limited
Journal:
Combustion Theory and Modelling
Issue Date:
18-Jan-2016
DOI:
10.1080/13647830.2015.1118556
Type:
Article
ISSN:
1364-7830; 1741-3559
Sponsors:
The authors gratefully acknowledge that this article is based upon research supported by Alstom (Switzerland) Ltd. and Alstom Power Inc. in collaboration with KAUST's Clean Combustion Research Center.
Additional Links:
http://www.tandfonline.com/doi/full/10.1080/13647830.2015.1118556
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Mechanical Engineering Program; Computational Physics and Materials Science (CPMS); Clean Combustion Research Center

Full metadata record

DC FieldValue Language
dc.contributor.authorVanteru, Mahendra Reddyen
dc.contributor.authorRahman, Mustafa M.en
dc.contributor.authorGandi, Appalaen
dc.contributor.authorElbaz, Ayman M.en
dc.contributor.authorSchrecengost, Robert A.en
dc.contributor.authorRoberts, William L.en
dc.date.accessioned2016-02-22T14:09:53Zen
dc.date.available2016-02-22T14:09:53Zen
dc.date.issued2016-01-18en
dc.identifier.citationCenosphere formation from heavy fuel oil: a numerical analysis accounting for the balance between porous shells and internal pressure 2016, 20 (1):154 Combustion Theory and Modellingen
dc.identifier.issn1364-7830en
dc.identifier.issn1741-3559en
dc.identifier.doi10.1080/13647830.2015.1118556en
dc.identifier.urihttp://hdl.handle.net/10754/596924en
dc.description.abstractHeavy fuel oil (HFO) as a fuel in industrial and power generation plants ensures the availability of energy at economy. Coke and cenosphere emissions from HFO combustion need to be controlled by particulate control equipment such as electrostatic precipitators, and collection effectiveness is impacted by the properties of these particulates. The cenosphere formation is a function of HFO composition, which varies depending on the source of the HFO. Numerical modelling of the cenosphere formation mechanism presented in this paper is an economical method of characterising cenosphere formation potential for HFO in comparison to experimental analysis of individual HFO samples, leading to better control and collection. In the present work, a novel numerical model is developed for understanding the global cenosphere formation mechanism. The critical diameter of the cenosphere is modelled based on the balance between two pressures developed in an HFO droplet. First is the pressure (Prpf) developed at the interface of the liquid surface and the inner surface of the accumulated coke due to the flow restriction of volatile components from the interior of the droplet. Second is the pressure due to the outer shell strength (PrC) gained from van der Walls energy of the coke layers and surface energy. In this present study it is considered that when PrC ≥ Prpf the outer shell starts to harden. The internal motion in the shell layer ceases and the outer diameter (DSOut) of the shell is then fixed. The entire process of cenosphere formation in this study is analysed in three phases: regression, shell formation and hardening, and post shell hardening. Variations in pressures during shell formation are analysed. Shell (cenosphere) dimensions are evaluated at the completion of droplet evaporation. The rate of fuel evaporation, rate of coke formation and coke accumulation are analysed. The model predicts shell outer diameters of 650, 860 and 1040 µm, and inner diameters are 360, 410 and 430 µm respectively, for 700, 900 and 1100 µm HFO droplets. The present numerical model is validated with experimental results available from the literature. Total variation between computational and experimental results is in the range of 3–7%.en
dc.description.sponsorshipThe authors gratefully acknowledge that this article is based upon research supported by Alstom (Switzerland) Ltd. and Alstom Power Inc. in collaboration with KAUST's Clean Combustion Research Center.en
dc.language.isoenen
dc.publisherInforma UK Limiteden
dc.relation.urlhttp://www.tandfonline.com/doi/full/10.1080/13647830.2015.1118556en
dc.rightsThis is an Accepted Manuscript of an article published by Taylor & Francis in Combustion Theory and Modelling on 18 Jan 2016, available online: http://wwww.tandfonline.com/10.1080/13647830.2015.1118556.en
dc.subjectheavy fuel oilen
dc.subjectcenosphereen
dc.subjectnumerical modellingen
dc.subjectpressure balanceen
dc.subjectasphalteneen
dc.titleCenosphere formation from heavy fuel oil: a numerical analysis accounting for the balance between porous shells and internal pressureen
dc.typeArticleen
dc.contributor.departmentClean Combustion Research Centeren
dc.contributor.departmentMechanical Engineering Programen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentComputational Physics and Materials Science (CPMS)en
dc.identifier.journalCombustion Theory and Modellingen
dc.eprint.versionPost-printen
dc.contributor.institutionMechanical Power Department, Faculty of Engineering Material, Helwan University, Cairo, Egypten
dc.contributor.institutionAlstom Power, Inc., Windsor, CT, USAen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorVanteru, Mahendra Reddyen
kaust.authorRahman, Mustafa M.en
kaust.authorGandi, Appalaen
kaust.authorElbaz, Ayman M.en
kaust.authorRoberts, William L.en
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