A model of the combustion of a porous carbon particle in oxygen

Gremyachkin, V. M.; Förtsch, Dieter; Schnell, Uwe; Hein, K. R. G.

doi:10.1016/s0010-2180(02)00349-8

Cited by 24 publications

(11 citation statements)

References 6 publications

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“…For all the cases considered, the ambient temperature, T ∞ is set to 300 K while the pressure is assumed to be constant at 1 atm across the entire computational domain as a result of the incompressible flow assumption. For the diffusion limited combustion of a 1 mm sized particle, increasing the porosity or the ambient oxygen mole fraction is seen to yield an increased burning rate constant, K. These predicted trends are consistent with previous analytical and computational studies [4,21,42] and experiments [14,16]. As porosity increases, the ratio of internal surface area to volume (A s ) increases allowing additional surface reaction to occur, and thereby increasing K. Similarly, as the ambient oxygen concentration is increased, the corresponding increase in oxygen flux for the present diffusion limited case leads to almost a linear increase in K, as seen in Figure 8.…”

Section: Parametric Investigation Of Porosity Oxygen Concentration supporting

confidence: 87%

“…Only a handful of investigations have considered full transport and reaction within the pore structure [6,7,20,21], however with highly simplified heterogeneous and homogeneous kinetic models. In contrast, the present effort includes not only the reaction of carbon with O 2 , H 2 O, and CO 2 , but also reactions of carbon with radical species.…”

Section: Introductionmentioning

confidence: 99%

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Oxidation of isolated porous carbon particles: Comprehensive numerical model

Kassebaum

Chelliah

2009

Combustion Theory and Modelling

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A general mathematical formulation and a numerical solution approach are developed to model the oxidation of an isolated porous carbon particle in a quiescent atmosphere under quasi-steady conditions. A key element of the approach developed is the ability to decouple the internal surface area effects from the surface kinetic rates. The governing equations are integrated numerically from the centre of the particle to the edge of the gas-phase thermal mixing layer, with a novel transition layer introduced at the particle external surface. The numerical approach developed is then applied to a range of particle sizes and porosities in an enriched oxidizing environment. The existence of limiting combustion regime as a function of particle size, porosity, and ambient oxygen mole fraction is explored based on the model developed. Comparisons of the predicted particle mass burning rate and surface temperature with recent experiments, as well as the limiting or extinction conditions, are also presented.

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Section: Parametric Investigation Of Porosity Oxygen Concentration supporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Oxidation of isolated porous carbon particles: Comprehensive numerical model

Kassebaum

Chelliah

2009

Combustion Theory and Modelling

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“…Thermal emission as a result of the exothermic oxidation reaction leads to the rising of temperature on the coke surface. According to provisions of [8][9][10] it was considered that the coke part of coal particle consists of carbon after completion of thermal decomposition process. Heterogeneous ignition of carbon occurs at the achievement of critical temperature [9] on particle surface.…”

Section: Problem Formulationmentioning

confidence: 99%

Numerical research of heat and mass transfer during low-temperature ignition of a coal particle

2015

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Numerical researches have been carried out to study the influence of air flow temperature and a fossil fuel particle rate on sufficient conditions of ignition in a "coal particle -air" system. Developed mathematical model takes into account interconnected processes of heat transfer in a coal particle and gas area, thermal decomposition of organic material, diffusion and gas-phase oxidation of volatiles, heating of a coke (carbon) and its heterogeneous ignition. The effect of low-temperature (about 600 K) ignition for a single coal particle is impossible even at variation of its rate (radius) from 0.05 mm to 0.5 mm. Nevertheless this process is possible for group of particles (two, three, et al.) situated at close-range from each other. The physical aspects of the problem are discussed.

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“…Because a theoretical model of the combustion of a porous carbon particle has to include the kinetics of the chemical reactions of carbon with oxygen as an essential part of the model, and the kinetics of this reaction are not suf ciently known at this time, no model of porous carbon combustion exists that describes all features of this process. Only a handful of investigations have considered full transport and reaction within the pores, however with highly simpli ed heterogeneous and homogeneous kinetic models [40][41][42][43]. The developed in [40] model for the combustion of a porous carbon particle considers the equations of heat and mass transfer, both in the gas phase around the particle and inside the pores.…”

Section: Tablementioning

confidence: 99%

“…Only a handful of investigations have considered full transport and reaction within the pores, however with highly simpli ed heterogeneous and homogeneous kinetic models [40][41][42][43]. The developed in [40] model for the combustion of a porous carbon particle considers the equations of heat and mass transfer, both in the gas phase around the particle and inside the pores.…”

Section: Tablementioning

confidence: 99%

Chemical Kinetic Modeling in Coal Gasification Processes: an Overview

et al. 2012

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<p>Coal is the fuel most able to cover world deficiencies in oil and natural gas. This motivates the development of new and more effective technologies for coal conversion into other fuels. Such technologies are focused on coal gasification with production of syngas or gaseous hydrocarbon fuels, as well as on direct coal liquefaction with production of liquid fuels. The benefits of plasma application in these technologies is based on the high selectivity of the plasma chemical processes, the high efficiency of conversion of different types of coal including those of low quality, relative simplicity of the process control, and significant reduction in the production of ashes, sulphur, and nitrogen oxides. In the coal gasifier, two-phase turbulent flow is coupled with heating and evaporation of coal particles, devolatilization of volatile material, the char combustion (heterogeneous/porous oxidation) or gasification, the gas phase reaction/oxidation (homogeneous oxidation) of gaseous products from coal particles. The present work reviews literature data concerning reaction kinetic modelling in coal gasification. Current state of related kinetic models for heterogeneous/homogeneous oxidation of coal particles, included plasma assisted, is reviewed.</p>

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A model of the combustion of a porous carbon particle in oxygen

Cited by 24 publications

References 6 publications

Oxidation of isolated porous carbon particles: Comprehensive numerical model

Oxidation of isolated porous carbon particles: Comprehensive numerical model

Numerical research of heat and mass transfer during low-temperature ignition of a coal particle

Chemical Kinetic Modeling in Coal Gasification Processes: an Overview

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