Boiler continuous drainage waste heat recovery device

The utility model relates to a waste heat recovery device for boiler continuous drainage water. The waste heat recovery device comprises a periodic blowdown flash tank, a waste heat recovery device and a waste heat recovery device, a first pipeline is arranged between the periodic blowdown flash tank and the heat exchanger; the raw water heating system is provided with a raw water input pipe and a raw water output pipe, a water diversion pipeline is arranged between the raw water input pipe and the cold water inlet of the heat exchanger, one end of the water diversion pipeline is connected with the raw water input pipe, and the other end of the water diversion pipeline is connected with the cold water inlet of the heat exchanger; a drainage pipeline is arranged between the raw water output pipe and the cold water outlet of the heat exchanger, one end of the drainage pipeline is connected with the raw water output pipe, and the other end of the drainage pipeline is connected with the cold water outlet of the h