Pacific Northwest National Laboratory (PNNL) has taken an integrated approach to address major technical issues in conversion of coal into clean-burning liquid fuel. The approach includes: 1) modeling of gasifier and slag flow, 2) experimental characterization of slag viscoelastic behavior as a function of temperature for representative slags and refractory-slag interactions, and 3) interplay of the modeling and experimental measurements to identify critical conditions beyond which refractory corrosion tends to increase sharply. Basic heat and mass balances were considered in the gasifier and flow models. Two new refractory spalling models were developed. An experimental design that encompassed the broad range of slag chemistries that were of interest to coal gasification was developed and implemented. Selected gasifier refractories were tested in a simulated gasifier environment in our laboratory to identify refractory degradation mechanisms. Preliminary results of the effort are summarized.