(336e) Fast CFD Based Optimization of Coal Moving Bed Gasifier

Yu, J., National Energy Technology Laboratory
Lu, L., National Energy Technology Laboratory
Shahnam, M., National Energy Technology Laboratory
Rogers, W. A., National Energy Technology Laboratory
A coal gasification model has been developed, based on Coarse Grained Discrete Element Model in MFiX. The gasification model has been validated with data from a 200 KWh moving bed gasifier. The validated CFD model is used to optimize the syngas composition of the gasifier for use in a Combined Heat and Power (CHP) process and for use in a Fischer-Tropsch (F-T) process. To accelerate the time to solution of the simulations, a 1-dimensional gasification model was developed to model the transient start up process of the moving bed gasifier. The 1-dimensional model accounts for the drying, pyrolysis, gasification and char combustion during the startup period. Once the gasifier has reached its operating temperature, the results from the 1-dimensional model is used as initial conditions to the 3-dimensional CFD model. This workflow led to achieving the steady state operating condition within 10 minutes of simulation time, using 3-dimensional MFiX-CGDEM.