METHOD FOR CONTROLLING INHIBITOR CONCENTRATION BY FREE ACID CONCENTRATION OF HYDROCHLORIC ACID IN ACID WASH EQUIPMENT

摘要

PURPOSE: A method for controlling the inhibitor concentration in accordance with the free acid concentration of hydrochloric acid in acid pickling equipment for reducing under acid pickling and over acid pickling by supplying an inhibitor in proportion to the free acid concentration calculated on-line is provided, which has the advantage of improving quality of hot rolled steel sheet. CONSTITUTION: The method for controlling the inhibitor concentration comprises the steps of: calculating the free acid concentration by measuring specific gravity and electric conductivity; calculating the input amount of free acid with the amount of hydrochloric acid to be supplied to a hydrochloric acid circulation tank and the free acid concentration; setting the input amount of an inhibitor in proportion to the input amount of free acid; and controlling an inhibitor flow controller, control valve and flow meter to introduce the input amount of the set inhibitor into an acid tank.