A generalised dynamic model for char particle gasification with structure evolution and peripheral fragmentation

Wang, Fu Yang and Bhatia, Suresh K. (2001) A generalised dynamic model for char particle gasification with structure evolution and peripheral fragmentation. Chemical Engineering Science, 56 12: 3683-3697. doi:10.1016/S0009-2509(01)00060-4


Author Wang, Fu Yang
Bhatia, Suresh K.
Title A generalised dynamic model for char particle gasification with structure evolution and peripheral fragmentation
Journal name Chemical Engineering Science   Check publisher's open access policy
ISSN 0009-2509
Publication date 2001-01-01
Sub-type Article (original research)
DOI 10.1016/S0009-2509(01)00060-4
Volume 56
Issue 12
Start page 3683
End page 3697
Total pages 15
Place of publication Amsterdam
Publisher Elsevier
Collection year 2001
Language eng
Subject C1
290601 Chemical Engineering Design
660101 Coal-electricity
Abstract A generalised model for the prediction of single char particle gasification dynamics, accounting for multi-component mass transfer with chemical reaction, heat transfer, as well as structure evolution and peripheral fragmentation is developed in this paper. Maxwell-Stefan analysis is uniquely applied to both micro and macropores within the framework of the dusty-gas model to account for the bidisperse nature of the char, which differs significantly from the conventional models that are based on a single pore type. The peripheral fragmentation and random-pore correlation incorporated into the model enable prediction of structure/reactivity relationships. The occurrence of chemical reaction within the boundary layer reported by Biggs and Agarwal (Chem. Eng. Sci. 52 (1997) 941) has been confirmed through an analysis of CO/CO2 product ratio obtained from model simulations. However, it is also quantitatively observed that the significance of boundary layer reaction reduces notably with the reduction of oxygen concentration in the flue gas, operational pressure and film thickness. Computations have also shown that in the presence of diffusional gradients peripheral fragmentation occurs in the early stages on the surface, after which conversion quickens significantly due to small particle size. Results of the early commencement of peripheral fragmentation at relatively low overall conversion obtained from a large number of simulations agree well with experimental observations reported by Feng and Bhatia (Energy & Fuels 14 (2000) 297). Comprehensive analysis of simulation results is carried out based on well accepted physical principles to rationalise model prediction. (C) 2001 Elsevier Science Ltd. AH rights reserved.
Keyword Engineering, Chemical
Char Gasification
Fragmentation
Micro-structure
Modelling
Porous Media
Reaction Engineering
Incipiently Fluidized-bed
Co/co2 Product Ratio
Coal Char
Combustion
Heat
Mass
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Chemical Engineering Publications
 
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Created: Wed, 15 Aug 2007, 01:58:16 EST