Discharged smoke afterheat recycling and emission reduction comprehensive application system for coal-fired boiler in thermal power plant

The utility model discloses a discharged smoke afterheat recycling and emission reduction comprehensive application system for a coal-fired boiler in a thermal power plant. Along a flow direction of smoke, an air preheater, a first low-temperature economizer, a low-temperature dust remover, a draught fan, a second low-temperature economizer and a desulfuration island are arranged on a pipeline between the boiler to a chimney sequentially; the inlet of the air preheater is communicated with a primary cold air pipeline and a secondary cold air pipeline respectively; a secondary air warmer is arranged on the secondary cold air pipeline; the secondary air warmer is communicated with the second low-temperature economizer through a water medium pipeline; and an expanded water tank and a water pump are arranged on the water medium pipeline. The low-temperature economizers are arranged into two sections; and one section is used for heating condensed water and the other section heats the secondary cold air at the inlet of the air preheater through a water medium. By the discharged smoke afterheat recycling and emission reduction comprehensive application system, the smoke afterheat can be used fully, so that the heat loss of the set is reduced, the energy consumption of equipment, such as the dust remover, the draught fan, an air feeder and the like is reduced, the power consumption rate of a factory is reduced, the economy of a power plant is improved, the energy consumption can be saved more efficiently, and construction for a low-carbon society is facilitated.