Simulation of a supercritical once-through boiler

Abstract

The problem addressed is that of improving the control system of an existing supercritical once-through boiler. To do this, it was necessary to construct a dynamic mathematical model of it. This paper describes the model that was developed; it is based on the nonlinear partial differential equations which describe the physical phenomena in the boiler. These equations involve transfer functions that cannot be obtained directly; they were found by linearizing the equations and estimating the values of unknown parameters from the boiler's input-output operational records. The model includes both forward and back ward causalities in determining the water and steam flow. Simulation results indicate that the model is valid and that the control system requires modifica tion. The investigated boiler has a capacity of 450 MW and is presently operating at Kainan Thermal Power Station of Kansai Electric Power Company.