Preheating system for preheating slab crystallizer based on waste flue gas and control method of preheating system

The invention discloses a preheating system for preheating a slab crystallizer based on waste flue gas and a control method of the preheating system. The preheating system for preheating the slab crystallizer based on the waste smoke comprises a heating cover arranged above the crystallizer in a covering mode and an air inducing pipeline connected with the heating cover and a hot air supply system, an air inlet pipe is installed on the heating cover, one end of the air inlet pipe extends into the heating cover and is located above a dummy bar head, and the other end of the air inlet pipe is communicated with the air inducing pipeline. A stop valve and a regulating valve are mounted on the air inducing pipeline; and hot air of the hot air supply system is baking flue gas in the intermediate tank. According to the preheating system for preheating the slab crystallizer based on the waste flue gas, the copper plate of the crystallizer is heated through the high-temperature flue gas, the temperature of the copper