Waste heat recycling air preheating bypass coal saving system and application thereof

The invention discloses a waste heat recycling air preheating bypass coal saving system and application thereof. A waste gas outlet of a boiler is connected with a gas inlet of a cyclone dust collector, a gas outlet of the cyclone dust collector is connected with a heat pipe of a heat exchanger, a branch is arranged at an opening of the cyclone dust collector and connected with a decompressor, and the decompressor is connected with the heat pipe of the heat exchanger in series. A heat pipe outlet of the heat exchanger is connected with a gas inlet of an electrostatic dust collector. A gas outlet of the electrostatic dust collector is provided with a second draught fan. A gas outlet of the second draught fan is connected with a waste gas cooler. The upper end of the waste gas cooler is provided with two circular ventilation holes. A circular gas outlet is provided with a sucking pump. The other end of the sucking pump is connected with a second preheater. A gas outlet of the second preheater is connected with a gas inlet of a first preheater. A gas outlet of the first preheater is connected with a circular gas inlet of the waste gas cooler to form a loop. The waste heat recycling air preheating bypass coal saving system is reasonable in design, easy and convenient to operate, high in preheat recycling rate, low in operation cost, capable of saving energy and protecting the environment and free of pollution to the air.