Dynamic simulation and phase plane analysis of entrained coal gasification

Abstract

Dynamic simulation and phase plane analysis techniques were used to examine the stability of an entrained coal gasifier. The mathematical model consists of a set of algebraic and ordinary differential equations which represent the time-dependent in terrelationships among reaction kinetics, heat transfers and mass transports; and the variable physical properties of both gaseous mixture and coal particles. For simplicity, the shift-reaction and volatilization were not considered in the study. This model is expected to be valid for dynamic simulation of gasification of char with low iron content and negligible shift reaction.

During simulation the coupled differential equations are solved by the Adams-Moulton numerical integration technique.

After the simulation is run to a steady state, the temperatures and composition of this system were perturbed in many com binations. The trajectories of variable changes were plotted in phase planes. It was noted that the system was stable for all the variable combinations tested.

The effects of pure proportional control on the dynamics of the gasifier were examined. Such control resulted in a faster return to the steady-state conditions.

Keywords

Adams-Moulton coal gasification dynamic en trainment phase plane analysis stability

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