Effect of slag viscosity model on transient simulations of wall slag flow in an entrained coal gasifier
The viscosity-temperature relation of slag determines its behavior inside an entrained flow coal gasifier. However, existing prediction models give results with large variations among them. We investigated the influence of different viscosity models in the prediction of the steady and transient behaviors of slag flow on the wall of a gasifier undergoing gas temperature changes. Five viscosity models adopted showed differences in the temperature (T250) at 25 Pa∙s as large as 97 K for the selected slag composition, which was used as the interface temperature between the solid and liquid slag. When the predicted viscosity and corresponding T250 increased, the solid slag became thicker and the dynamic response of the slag became slower. In contrast, the differences in the liquid slag thickness were small. The influence of T250 predicted was dominant, compared to that of different viscosity curves of the liquid slag.
KeywordsAsh Deposition Coal Gasification Entrained Gasifier Numerical Model Slag Layer
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- 1.L.D. Smoot and P. J. Smith, Coal combustion and gasification, Springer Science & Business Media (2013).Google Scholar
- 8.S. Vargas, Straw and coal ash rheology, Department of Chemical Engineering, Technical University of Denmark (2001).Google Scholar
- 10.K.C. Mills, L. Yuan and R.T. Jones, J. South. Afr. Inst. Min. Metall., 111, 649 (2011).Google Scholar
- 15.G. Urbain, Trans. J. Br. Ceram. Soc., 80, 139 (1981).Google Scholar
- 16.W.T. Reid, External corrosion and deposits: Boilers and gas turbines, Fuel and Energy Science Series; American Elsevier Publishing Co., New York (1971).Google Scholar
- 17.J. Watt and F. Fereday, J. Inst. Fuel, 42, 99 (1969).Google Scholar
- 19.D. P. Kalmanovitch and M. Frank, An effective model of viscosity for ash deposition phenomena, Proceedings of mineral matter and ash deposition from coal, 22 (1988).Google Scholar
- 21.S. Vargas, F. Frandsen and K. Dam-Johansen, Elsam-idemitsu kosan cooperative research project: Performance of viscosity models for hightemperature coal ashes, Department of Chemical Engineer-ing, Technical University of Denmark, CHEC Report (1997).Google Scholar
- 23.H. Saxén and X. Zhang, Neural-network based model of blast furnace slag viscosity, Proceedings of the International Conference on Engineering Application of Neural Networks, 167 (1997).Google Scholar