DEVELOPMENT AND APPLICATIONS OF THE THERMODYNAMIC AND VISCOSITY MODELS FOR COMPLEX COAL ASH SLAG SYSTEMS

摘要

One of the key issues in the operation of entrained flow slagging gasifiers (e.g. IGCC) is the complex behaviour of coal ash slags. For successful prediction and modelling of the various processes taking place in slagging gasifiers it is necessary to understand and evaluate such fundamental aspects of the chemistry and physico-chemical properties of coal ash slag systems as phase equilibria and viscosity. Following systematic studies of slag behaviour, accurate thermodynamic and viscosity models have been developed. Recently, a modified high temperature viscometer has been developed that enables slag samples to be quenched after viscosity measurements; thereby allowing direct information on the structure, phase assemblage and composition of heterogeneous slags to be obtained. Examples illustrating application of the thermodynamic and viscosity models to complex industrial issues, such as coal ash slag deposit formation and ash adhesion, are presented in the paper.