Simulation of a membrane unit for oxyfuel power plants under consideration of realistic BSCF membrane properties

Engels, Stefan; Beggel, Franz Jakob; Modigell, Michael; Stadler, Hannes

doi:10.1016/j.memsci.2010.01.048

Cited by 107 publications

(46 citation statements)

References 28 publications

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“…On the sweep side of the ITM, the sweep gas stream, i.e., the fuel stream, tends to be preheated and to require diluents such as CO2 and H2O along with the fuel in order to control the flow rate and the flame temperature [7,15]. In addition, the oxygen permeation flux, i.e., the oxidizer stream, is influenced by oxygen consumption and heat released from the oxidation reactions, which affect the oxygen concentration in the immediate vicinity of the membrane and the membrane temperature [16].…”

Section: Introductionmentioning

confidence: 99%

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

Hong

Kirchen

Ghoniem

2013

Combustion and Flame

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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 * Corresponding author. Tel.: +1 617 253 2295; Fax: +1 617 253 5981 Email address: ghoniem@mit.edu (Ahmed F. Ghoniem) 2 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.

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Section: Introductionmentioning

confidence: 99%

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

Hong

Kirchen

Ghoniem

2013

Combustion and Flame

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“…The complete conversion of fuel with pure oxygen yields only carbon dioxide and water [20,21]. By condensing water, the exhaust stream contains high purity carbon dioxide.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of ion transport membrane reactors: Oxygen permeation and transport and fuel conversion

Hong

Kirchen

Ghoniem

2012

Journal of Membrane Science

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Ion transport membrane (ITM) based reactors have been suggested as a novel technology for several applications including fuel reforming and oxy-fuel combustion, which integrates air separation and fuel conversion while reducing complexity and the associated energy penalty. To utilize this technology more effectively, it is necessary to develop a better understanding of the fundamental processes of oxygen transport and fuel conversion in the immediate vicinity of the membrane. In this paper, a numerical model that spatially resolves the gas flow, transport and reactions is presented. The model incorporates detailed gas phase chemistry and transport. The model is used to express the oxygen permeation flux in terms of the oxygen concentrations at the membrane surface given data on the bulk concentration, which is necessary for cases when mass transfer limitations on the permeate side are important and for reactive flow modeling. The simulation results show the dependence of oxygen transport and fuel conversion on the geometry and flow parameters including the membrane temperature, feed and sweep gas flow, oxygen concentration in the feed and fuel concentration in the sweep gas.

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“…Energy losses in a range of 6 to 10% points seem to be possible. 64,[72][73][74] Chemical looping research is actually focusing on investigating suitable materials. Efficiency losses are estimated to be approximately 8% points.…”

mentioning

confidence: 99%

Worldwide innovations in the development of carbon capture technologies and the utilization of CO2

Markewitz

Kuckshinrichs

Leitner

et al. 2012

Energy Environ. Sci.

1,054

652

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Simulation of a membrane unit for oxyfuel power plants under consideration of realistic BSCF membrane properties

Cited by 107 publications

References 28 publications

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

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

Numerical simulation of ion transport membrane reactors: Oxygen permeation and transport and fuel conversion

Worldwide innovations in the development of carbon capture technologies and the utilization of CO2

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