Oxy-fuel combustion of pulverized coal: Characterization, fundamentals, stabilization and CFD modeling

Chen, Lei; Yong, Sze Zheng; Ghoniem, Ahmed F.

doi:10.1016/j.pecs.2011.09.003

Cited by 859 publications

(451 citation statements)

References 163 publications

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“…Matching the combustion temperature requires the introduction of a substantial amount of an other diluent such as CO2 in the sweep gas stream [37]. In typical oxy-fuel combustion reactors, a fraction of the flue gas stream is recirculated back to the reactor in the form of wet or dry CO2 to control the flame structure and its temperature.…”

Section: Reaction Environment Supported By An Itmmentioning

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: Reaction Environment Supported By An Itmmentioning

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 structure of the char plays a determinant role in its reactivity during combustion. In the case of oxy-fuel combustion technology, the substitution of an inert (N 2 ) for a reactive (CO 2 ) gas in the devolatilization atmosphere could affect the morphology, porosity and surface area of the resultant char and in turn its reactivity [5]. H 2 O is also present in the RFG at a considerably lower concentration (up to ~10%) than that of CO 2 , so its effect on the devolatilization step is expected to be low.…”

Section: Introductionmentioning

confidence: 99%

Biomass devolatilization at high temperature under N2 and CO2: Char morphology and reactivity

Gil

Riaza

Álvarez

et al. 2015

Energy

116

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“…Therefore, we can say with confidence that in the near future (according to forecasts [8]), coal will remain the main energy resources. However, traditional methods of burning coal (e.g., a torch [5] or layers [6]) do not provide satisfactory indicators emissions of oxides of nitrogen and sulfur. Recent ones stimulate the creation and implementation of new (ecological and energy perspective), the so-called "clean" coal technologies.…”

Section: Introductionmentioning

confidence: 99%

Ignition of Water Coal Particles Coated with a Waterfilm in the Stream of High-Temperature Environment

Кузнецов

Gutareva

Bugaeva

et al. 2015

MATEC Web of Conferences

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The characteristics and conditions of the ignition of coal-water fuel droplets (WCF) in a surface coating with a thin layer of water last film have been determined experimentally. A significant impact on the dynamics of the water layer of the thermal preparation and ignition of the fuel particles has been established. It has been shown that the time of evaporation of water of the surface layer can take up to 50% of all of the induction period. The latter indicates the need to consider the existence of the surface of the film during the process modeling of ignition of coal-water particles.

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Oxy-fuel combustion of pulverized coal: Characterization, fundamentals, stabilization and CFD modeling

Cited by 859 publications

References 163 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

Biomass devolatilization at high temperature under N2 and CO2: Char morphology and reactivity

Ignition of Water Coal Particles Coated with a Waterfilm in the Stream of High-Temperature Environment

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