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

Wang, Fu Yang ; Bhatia, Suresh K. (2001) A generalised dynamic model for char particle gasification with structure evolution and peripheral fragmentation Chemical Engineering Science, 56 (12). pp. 3683-3697. ISSN 0009-2509

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Official URL: http://linkinghub.elsevier.com/retrieve/pii/S00092...

Related URL: http://dx.doi.org/10.1016/S0009-2509(01)00060-4


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 large a 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.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Char Gasification; Fragmentation; Micro-structure; Modelling; Porous Media; Reaction Engineering
ID Code:2871
Deposited On:09 Oct 2010 05:39
Last Modified:17 May 2011 06:55

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