Dynamic Modeling and Control of Integrated Coal Gasification Combined Cycle Units

摘要

This thesis investigates the dynamic behavior and control of integrated coal gasification combined cycle units, operating in a load-following mode on the national grid. Startup, shutdown and accident related behavior are not considered. A conceptual 250 MW unit featuring an oxygen-blown pulverized coal gasifier according to the Shell Coal Gasification Process (SCGP) has been taken as the subject of a simulation study. An attempt at model validation has been made using experimental data from the SCGP demonstration unit in Deer Park, Texas. Using the concept of Model Predictive Control, sample constraints on gasifier conditions and syngas pressure profile were explicitly accounted for in the control algorithm. Whereas the former are found to be easily accommodated without any significant impact on load-following control, the latter inevitably lead to a deterioration in performance. Conclusions and recommendations on dynamic modeling and unit power control are provided.