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

Abstract

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.

Description

technical field [0001] The invention relates to a comprehensive application system for waste heat recovery and emission reduction of coal-fired boilers in thermal power plants. Background technique [0002] Smoke loss is the most important heat loss in boiler operation, accounting for about 60%-70% of boiler heat loss. The design value of the exhaust gas temperature of boilers burning anthracite, lean coal, and bituminous coal is usually 120°C-130°C, and the design value of exhaust gas temperature of boilers burning lignite is usually around 155°C, and the actual operating exhaust temperature of boilers in thermal power plants in my country is mostly higher than the design value. In order to reduce the loss of exhaust gas, reduce the temperature of exhaust gas and improve the economy of power plants, some projects currently use low-temperature economizers to utilize the waste heat of flue gas. figure 1 It is a schematic diagram of the connection of the existing traditional ...

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Problems solved by technology

[0003] A typical low-temperature economizer system uses flue gas to heat condensate water to improve the efficiency of the heat recovery system, but this system cannot integrate other technologies to maximize the use of flue gas waste heat

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