JPS6454101A - Automatic controller for boiler - Google Patents

Abstract

PURPOSE: To prevent an accident of a plant in a boiler of power generating plant by a method wherein an amount of feeding water, an amount of fuel to be fed and an amount of air are controlled by a boiler master signal corrected in response to an increased amount of water contained in the boiler under abnormal states such as FCB and occurrence of load run-back state. CONSTITUTION: A drum type power generating plant is comprised of a boiler main body 20, a high pressure turbine 2, a middle pressure turbine 31 and a power generator 3. This plant is controlled by a boiler automatic control device 302. That is, a boiler master signal is corrected in response to a variation in amount of water in a boiler drum 10, a downcomer 41 of the boiler drum 10 and a water wall tube 40, thereby a flow rate of fuel, a flow rate of combustion air and a flow rate of feedwater are controlled and a drum level is controlled within a lower limit and an upper limit even in the case of abnormal state. In addition, in the case of an once-through boiler having no boiler drum, the boiler master signal is corrected in response to a variation of an amount of water in the furnace wall water tube 40, a flow rate of fuel, a flow rate of combustion air and a flow rate of feedwater are controlled and a waterwall metal temperature of the furnace is controlled within a predetermined value even in the case of abnormal condition.