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Slag Behavior in Gasifiers. Part II: Constitutive Modeling of Slag
U.S. Department of Energy (DOE), National Energy Technology Laboratory (NETL), 626 Cochrans Mill Road, P.O. Box 10940, Pittsburgh, PA 15236-0940, USA
* Author to whom correspondence should be addressed.
Received: 30 October 2012; in revised form: 8 January 2013 / Accepted: 22 January 2013 / Published: 7 February 2013
Abstract: The viscosity of slag and the thermal conductivity of ash deposits are among two of the most important constitutive parameters that need to be studied. The accurate formulation or representations of the (transport) properties of coal present a special challenge of modeling efforts in computational fluid dynamics applications. Studies have indicated that slag viscosity must be within a certain range of temperatures for tapping and the membrane wall to be accessible, for example, between 1,300 °C and 1,500 °C, the viscosity is approximately 25 Pa·s. As the operating temperature decreases, the slag cools and solid crystals begin to form. Since slag behaves as a non-linear fluid, we discuss the constitutive modeling of slag and the important parameters that must be studied. We propose a new constitutive model, where the stress tensor not only has a yield stress part, but it also has a viscous part with a shear rate dependency of the viscosity, along with temperature and concentration dependency, while allowing for the possibility of the normal stress effects. In Part I, we reviewed, identify and discuss the key coal ash properties and the operating conditions impacting slag behavior.
Keywords: slag; gasification; viscosity; non-Newtonian fluids; rheology; constitutive relations; coal
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Massoudi, M.; Wang, P. Slag Behavior in Gasifiers. Part II: Constitutive Modeling of Slag. Energies 2013, 6, 807-838.
Massoudi M, Wang P. Slag Behavior in Gasifiers. Part II: Constitutive Modeling of Slag. Energies. 2013; 6(2):807-838.
Massoudi, Mehrdad; Wang, Ping. 2013. "Slag Behavior in Gasifiers. Part II: Constitutive Modeling of Slag." Energies 6, no. 2: 807-838.