Industrial furnace and process for controlling the combustion inside

An industrial furnace used for treating semi-finished and siderurgical products, metal and inorganic materials, the industrial furnace comprising:

• a hot chamber in which a combustion takes place and hot gases generated by the combustion come in direct contact with the materials to be treated (p) in the industrial furnace itself;
• and
• a combustion stabilising system comprising:
• an injection system comprising at least a mixer configured to mix a fuel and a diluent before injecting them into the hot chamber;
• wherein the diluent has an effect of reducing an amount of nitrogen oxides in combustion products;
• and
• a control system including a vibration detector configured to detect any of optical electromagnetical, acoustic and mechanical vibrations in the hot chamber, the control system being configured to control the injection system according to a signal output by vibration detector to eliminate or reduce a formation of flames or other hot spots during the combustion in the hot chamber, where the hot spots indicate that the combustion is taking place in presence of flame, wherein
• the control system controls the injection system according to detections of the vibration detector by:
• comparing a frequency spectrum of the signal output by the vibration detector with a target frequency spectrum of target combustion conditions of the hot chamber;
• and
• adjusting a flow rate of the fuel or the diluent fed into the hot chamber so that the frequency spectrum becomes the target frequency spectrum.