In production processes such as steel and non-ferrous metal smelting, a large amount of high-temperature flue gas is generated. These fumes not only carry dust and harmful gases, but also contain considerable waste heat. Installing plate heat exchangers at the flue gas emission channel can preheat the fresh air with the help of high-temperature flue gas, achieving the effect of heat recovery. Taking the blast furnace ironmaking workshop as an example, with the help of plate heat exchangers, the heat of high-temperature flue gas can be transferred to the cold air sent into the workshop. On the one hand, this measure can reduce the temperature of flue gas emissions and alleviate the load on subsequent environmental treatment equipment; On the other hand, preheated fresh air can optimize the working environment in the workshop and reduce heating energy consumption. In addition, in the local ventilation system of the metallurgical workshop, plate heat exchangers can also carry out heat recovery work for exhaust containing oil stains or metal dust, achieving energy-saving goals while preventing the spread of pollutants.