(598t) A Semi-Empirical Approach to Modeling and Simulation of Gasification Process

There has been growing interest in understanding the coal gasification processes as a means of producing gaseous fuel. The inherent characteristics of coal gasification are complex and due to the high costs associated with the experimental investigations, modeling and simulation tools are becoming increasingly popular to assist with the design, analysis and optimization of this complex process. Most of the efforts to implement a gasifier model have been focused on two different approaches of euilibrium modeling and kinetic modeling.

The chemical equilibrium hypothesis assumes the gasification reactions have sufficiently fast kinetics to reach chemical reaction equilibria, which leads to over-prediction of the extent of the gasification reactions [1, 2, 3]. On the other hand, the kinetic based models taking into account transport and diffusion phenomena occurring in the reactor, which need detailed hydrodynamic and reaction kinetics for the heterogeneous and homogeneous chemical reactions [4, 5].

In this study, a versatile and user friendly gasifier simulation model was developed which incorporates a MS Excel interface aiming to provide a guide to gasification process analysis, evaluation and improvement.  The model uses a set of semi-empirical correlations for the reaction conversions, which are based on experimental data, to predict the syngas composition, flow rate, and performance of the gasifier.  The results of the parametric studies performed for the assessment of the effect of operating conditions, a parametric study are discussed and presented.

References:

1- Li, X., Grace, J.R., Watkinson, A.P., Lim, C.J., Ergudenler , A., “Equilibrium modeling of gasification: a free energy minimization approach and its application to a circulating fluidized bed coal gasifier”, Fuel 80 (2001): 195-207

2- Huang, H.J., Ramaswamy, S., “Modeling Biomass Gasification Using Thermodynamic Equilibrium Approach”, Appl Biochem Biotechnol 154 (2009):14-25             

3- Emuna, F., Gadallaa, M., Majozib, T., Boer, D., “Integrated gasification combined cycle (IGCC) process simulation and optimization”, Computers and Chemical Engineering 34 (2010) 331–338

4- Monaghan R.F.D, Ghoniem, A.F., “A dynamic reduced order model for simulating entrained flow gasifiers: Part I: Model development and description”, Fuel 91 (2012) 61–80

5- Kim, Y.J., Lee, J.M., Kim, S.D., “Modeling of coal gasification in an internally circulating fluidized bed reactor with draught tube”, Fuel 79 (2000) 69–77