Laminar oxy-fuel diffusion flame supported by an oxygen-permeable-ion-transport membrane

Handle URI:
http://hdl.handle.net/10754/598691
Title:
Laminar oxy-fuel diffusion flame supported by an oxygen-permeable-ion-transport membrane
Authors:
Hong, Jongsup; Kirchen, Patrick; Ghoniem, Ahmed F.
Abstract:
A numerical model with detailed gas-phase chemistry and transport was used to predict homogeneous fuel conversion processes and to capture the important features (e.g., the location, temperature, thickness and structure of a flame) of laminar oxy-fuel diffusion flames stabilized on the sweep side of an oxygen permeable ion transport membrane (ITM). We assume that the membrane surface is not catalytic to hydrocarbon or syngas oxidation. It has been demonstrated that an ITM can be used for hydrocarbon conversion with enhanced reaction selectivity such as oxy-fuel combustion for carbon capture technologies and syngas production. Within an ITM unit, the oxidizer flow rate, i.e., the oxygen permeation flux, is not a pre-determined quantity, since it depends on the oxygen partial pressures on the feed and sweep sides and the membrane temperature. Instead, it is influenced by the oxidation reactions that are also dependent on the oxygen permeation rate, the initial conditions of the sweep gas, i.e., the fuel concentration, flow rate and temperature, and the diluent. In oxy-fuel combustion applications, the sweep side is fuel-diluted with CO2, and the entire unit is preheated to achieve a high oxygen permeation flux. This study focuses on the flame structure under these conditions and specifically on the chemical effect of CO2 dilution. Results show that, when the fuel diluent is CO2, a diffusion flame with a lower temperature and a larger thickness is established in the vicinity of the membrane, in comparison with the case in which N2 is used as a diluent. Enhanced OH-driven reactions and suppressed H radical chemistry result in the formation of products with larger CO and H2O and smaller H2 concentrations. Moreover, radical concentrations are reduced due to the high CO2 fraction in the sweep gas. CO2 dilution reduces CH3 formation and slows down the formation of soot precursors, C2H2 and C2H4. The flame location impacts the species diffusion and heat transfer from the reaction zone towards the membrane, which affects the oxygen permeation rate and the flame temperature. © 2012 The Combustion Institute.
Citation:
Hong J, Kirchen P, Ghoniem AF (2013) Laminar oxy-fuel diffusion flame supported by an oxygen-permeable-ion-transport membrane. Combustion and Flame 160: 704–717. Available: http://dx.doi.org/10.1016/j.combustflame.2012.11.014.
Publisher:
Elsevier BV
Journal:
Combustion and Flame
KAUST Grant Number:
KSU-I1-010-01
Issue Date:
Mar-2013
DOI:
10.1016/j.combustflame.2012.11.014
Type:
Article
ISSN:
0010-2180
Sponsors:
The authors would like to thank the King Fahd University of Petroleum and Minerals (KFUPM) in Dhahran, Saudi Arabia, for funding the research reported in this paper through the Center of Clean Water and Clean Energy at Massachusetts Institute of Technology and KFUPM under the Project No. R2-CE-08. This work is also supported by King Abdullah University of Science and Technology Grant No. KSU-I1-010-01.
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DC FieldValue Language
dc.contributor.authorHong, Jongsupen
dc.contributor.authorKirchen, Patricken
dc.contributor.authorGhoniem, Ahmed F.en
dc.date.accessioned2016-02-25T13:34:31Zen
dc.date.available2016-02-25T13:34:31Zen
dc.date.issued2013-03en
dc.identifier.citationHong J, Kirchen P, Ghoniem AF (2013) Laminar oxy-fuel diffusion flame supported by an oxygen-permeable-ion-transport membrane. Combustion and Flame 160: 704–717. Available: http://dx.doi.org/10.1016/j.combustflame.2012.11.014.en
dc.identifier.issn0010-2180en
dc.identifier.doi10.1016/j.combustflame.2012.11.014en
dc.identifier.urihttp://hdl.handle.net/10754/598691en
dc.description.abstractA numerical model with detailed gas-phase chemistry and transport was used to predict homogeneous fuel conversion processes and to capture the important features (e.g., the location, temperature, thickness and structure of a flame) of laminar oxy-fuel diffusion flames stabilized on the sweep side of an oxygen permeable ion transport membrane (ITM). We assume that the membrane surface is not catalytic to hydrocarbon or syngas oxidation. It has been demonstrated that an ITM can be used for hydrocarbon conversion with enhanced reaction selectivity such as oxy-fuel combustion for carbon capture technologies and syngas production. Within an ITM unit, the oxidizer flow rate, i.e., the oxygen permeation flux, is not a pre-determined quantity, since it depends on the oxygen partial pressures on the feed and sweep sides and the membrane temperature. Instead, it is influenced by the oxidation reactions that are also dependent on the oxygen permeation rate, the initial conditions of the sweep gas, i.e., the fuel concentration, flow rate and temperature, and the diluent. In oxy-fuel combustion applications, the sweep side is fuel-diluted with CO2, and the entire unit is preheated to achieve a high oxygen permeation flux. This study focuses on the flame structure under these conditions and specifically on the chemical effect of CO2 dilution. Results show that, when the fuel diluent is CO2, a diffusion flame with a lower temperature and a larger thickness is established in the vicinity of the membrane, in comparison with the case in which N2 is used as a diluent. Enhanced OH-driven reactions and suppressed H radical chemistry result in the formation of products with larger CO and H2O and smaller H2 concentrations. Moreover, radical concentrations are reduced due to the high CO2 fraction in the sweep gas. CO2 dilution reduces CH3 formation and slows down the formation of soot precursors, C2H2 and C2H4. The flame location impacts the species diffusion and heat transfer from the reaction zone towards the membrane, which affects the oxygen permeation rate and the flame temperature. © 2012 The Combustion Institute.en
dc.description.sponsorshipThe authors would like to thank the King Fahd University of Petroleum and Minerals (KFUPM) in Dhahran, Saudi Arabia, for funding the research reported in this paper through the Center of Clean Water and Clean Energy at Massachusetts Institute of Technology and KFUPM under the Project No. R2-CE-08. This work is also supported by King Abdullah University of Science and Technology Grant No. KSU-I1-010-01.en
dc.publisherElsevier BVen
dc.subjectCO2 dilutionen
dc.subjectDiffusion flameen
dc.subjectIon transport membrane reactoren
dc.subjectOxy-fuel combustionen
dc.subjectOxygen permeationen
dc.subjectSyngas productionen
dc.titleLaminar oxy-fuel diffusion flame supported by an oxygen-permeable-ion-transport membraneen
dc.typeArticleen
dc.identifier.journalCombustion and Flameen
dc.contributor.institutionMassachusetts Institute of Technology, Cambridge, United Statesen
dc.contributor.institutionThe University of British Columbia, Vancouver, Canadaen
kaust.grant.numberKSU-I1-010-01en
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