METHOD FOR AUTOMATICALLY CONTROLLING BY-PASS VALVE OF HEAT EXCHANGER OF BLAST AIR HEATING FURNACE

摘要

PURPOSE: A method for automatically controlling a by-pass valve of a heat exchanger of a blast air heating furnace is provided to automatically control the by-pass valve for maintaining a temperature of a heat exchanging equipment to reduce an energy by pre-heating an air for burning and a BFG using a waste heat of exhaust gas generated during a burning process of air heating furnace. CONSTITUTION: Each measured value is calculated by measuring a coke gas, a blast furnace gas, air for burning, a temperature of exhaust gas, a flux and a temperature of a thermal media inlet supplied into a blast furnace. A coefficient of gas electric heat and a coefficient of thermal media electric heat are calculated based on each measured value. An electric heat coefficient of film outside a tube and an electric heat coefficient of film inside the tube are yielded by using the coefficient of gas electric heat, the coefficient of thermal media electric heat and each measured value. A temperature of tube is yielded by using the electric heat coefficient of film outside the tube and the electric heat coefficient of film inside the tube. A point generated by an acid is yielded by measuring a signal of oxide. The temperature of tube is inputted as a measured value and the point generated by the acid is inputted as a set value. A compensated value of valve output is converted to a signal by using a shifting signal of burning furnace to prevent a falling of temperature when the burning furnace is shifted. And a by-pass valve is operated by the signal.