Influence of gas and solid phase thermo-physical and transport properties on the thermo-chemical conversion of char in reacting media: intra-particle, microscopic and temporal mass loss-based sensitivity analysis

Mohammed Asheruddin, N and Shivapuji, AM and Srinivasaiah, D (2021) Influence of gas and solid phase thermo-physical and transport properties on the thermo-chemical conversion of char in reacting media: intra-particle, microscopic and temporal mass loss-based sensitivity analysis. In: Combustion Theory and Modelling, 25 (4). pp. 589-630.

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Abstract

The article addresses the implications of adopting (a) non-kinetic theory-based correlations for the estimation of thermodynamic and transport properties and (b) over-simplifying assumptions, as reported in literature, in the numerical simulation of thermo-chemical conversion of char. A one-dimensional char thermo-chemical conversion model with discretisation to capture intra-particle gradients of temperature and species is developed. Species and mixture property estimations are based on kinetic theory approaches, and all extraneous assumptions are eliminated. Simulation results indicate char conversion in air and (Formula presented.) to be near diffusion (Formula presented.) and near kinetic (Formula presented.) limit, respectively, while char conversion in (Formula presented.) has a competitive influence of both diffusion and kinetics (Formula presented.). Literature-specific correlations yield an order of magnitude deviation (up to 800) in the properties (thermal conductivity, specific heat, mass diffusivity). Adopting mole/mass fraction weighted averaging for mixture transport properties results in variations to the extent of 85. Unity Lewis number assumption introduces one order magnitude deviation in presence of (Formula presented.). It is observed that the deviations introduced in conversion process can be surmounted by using correction factor in the kinetic rate parameters, a prevalent practice. Such an approach is however thermodynamically untenable. © 2021 Informa UK Limited, trading as Taylor & Francis Group.

Item Type:	Journal Article
Publication:	Combustion Theory and Modelling
Publisher:	Taylor and Francis Ltd.
Additional Information:	The copyright for this article belongs to Taylor and Francis Ltd.
Keywords:	Chemical analysis; Kinetic theory; Kinetics; Mixtures; Sensitivity analysis; Specific heat, Correction factors; Diffusion and kinetics; Kinetic rate parameters; Mixture properties; Simplifying assumptions; Thermochemical Conversion; Thermodynamic and transport properties; Weighted averaging, Thermal conductivity
Department/Centre:	Division of Mechanical Sciences > Centre for Sustainable Technologies (formerly ASTRA)
Date Deposited:	16 Aug 2021 10:46
Last Modified:	17 Aug 2021 06:40
URI:	http://eprints.iisc.ac.in/id/eprint/69190

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