Full process control strategy of fuel based on water-coal ratio of ultra supercritical units

In order to realize the full process control of fuel in ultra supercritical units, fuel control strategy of feeders in start-up stage to guarantee the stability of coal-burning is proposed firstly. The control strategy of coal feeder which can make the bias trend to zero automatically is discussed. Control strategy of base amount of fuel is presented. The base amount of fuel in start-up phase is determined by states of units: cold state, warm state, hot state and extreme hot state. Water-coal ratio controls separator inlet temperature, outlet flue temperature, main steam pressure or separator inlet superheat in different start-up stages. The control strategy has been successfully applied to 1036MW ultra-supercritical units. It is a valuable reference for the design of similar control system.