Exhaust gas waste heat recovery and emission reduction comprehensive application system for coal-fired boiler in thermal power plant

The invention discloses an exhaust gas waste heat recovery and emission reduction comprehensive application system for a coal-fired boiler in a thermal power plant. In the invention, along the flow direction of flue gas, an air preheater, a first low temperature economizer, a low temperature dust collector, a draught fan, a second low temperature economizer and a desulfuration island are sequentially arranged on a pipe between the boiler and a chimney, wherein, the inlet of the air preheater is respectively communicated with a cold primary air pipe and a cold secondary air pipe; the cold secondary air pipe is provided with a secondary air heater; the secondary air heater is communicated with the second low temperature economizer via a coal-water pipe; the coal-water pipe is provided with an expansion tank and a water pump; and the low temperature economizer is divided into two segments, wherein, one segment is used for heating condensed water, and the other section is used for heating the cold secondary air at the inlet of the air preheater by virtue of a water medium. The exhaust gas waste heat recovery and emission reduction comprehensive application system has the beneficial effects of maximally utilizing the gas waste heat, reducing heat consumption of a machine set, lowering energy consumption of equipment such as the dust collector, the draught fan, a blower and the like, reducing the power consumption rate of the thermal power plant, improving the economical efficiency of the thermal power plant, more efficiently saving the energy consumption, and benefiting construction of the lowcarbon society.