An Integrated Approach to Coal Gasifier Testing, Modeling, and Process Optimization

Gasification is an important method of converting coal into clean burning fuels and high-value industrial chemicals. However, gasifier reliability can be severely limited by rapid degradation of the refractory lining in hot-wall gasifiers. The Pacific Northwest National Laboratory (PNNL) is performing multidisciplinary research to provide the experimental data and the engineering models needed to control gasifier operation for extended refractory life. Our experimental program includes prediction of slag viscosity using empirical viscosity models encompassing US coals, characterization of selected slag-refractory interaction including transport of slag/refractory components at the slag-refractory interface, and measurement of slag penetration into refractories as a function of time and temperature. The experimental data is used in slag flow, slag penetration, and refractory damage models to predict the operating temperature limits for increased refractory life. A simplified entrained flow gasifier model is also being developed to simulate one-dimensional axial flow with average axial velocity, coal devolatilization, and combustion kinetics. Combining the slag flow, refractory degradation, and gasifier models will provide a powerful tool to predict the coal and oxidant feed rates and control the gasifier operation to balance coal conversion efficiency with increased refractory life. A research scale gasifier has also been constructed at PNNL to providemore » syngas for coal conversion and carbon sequestration research, and also valuable datasets on operating conditions for validating the modeling results.« less