A plate heat exchanger is a high-efficiency heat exchanger assembled from a series of metal plates with a certain corrugated shape. The plate heat exchanger is composed of a group of metal plates, and there are four corner holes on the plate for the cooling and heating media to pass through.The hot and cold fluids flow in the channels at intervals, and the hot and cold fluids exchange heat through the panel walls to achieve the desired effect during the flow.Printing and dyeing plants also use titanium plate and plate heat exchangers to recover waste heat from dyeing wastewater. The hot water in the hot water tank supplies water to the dyeing tank, and the dyed waste water is directly discharged into the waste water tank.At this time, the temperature of the wastewater in the tank is about 80 ° C. Then pressurized by the waste water pump and sent to the titanium plate and plate heat exchanger for cooling, and then released after releasing heat.The cold water in the cooling water tank is pressurized and sent to the titanium plate heat exchanger through the water pump to cool the dyed wastewater. It absorbs heat and its temperature rises from 20 ° C to 70 ° C, then it is poured into a hot water tank, mixed with the hot water supplied from the boiler, and used as the supply water for the dyed drainage in the dyeing tank. The waste heat recovery device can recover waste heat up to 6.9GJ per hour, and its energy saving benefit is extremely significant.