System for utilizing flue gas waste heat of coal-fired boiler

Abstract

The invention discloses a system for utilizing flue gas waste heat of a coal-fired boiler. The system comprises a boiler, an air preheater, a first-stage low-temperature economizer, an electric dust remover, an induced draft fan, a second-stage low-temperature economizer, a desulfurizing tower and a chimney, wherein the boiler, the air preheater, the first-stage low-temperature economizer, the electric dust remover, the induced draft fan, the second-stage low-temperature economizer, the desulfurizing tower and the chimney are sequentially connected; the two-stage low-temperature economizer andthe one-stage low-temperature economizer both communicate with a side water supply system; the side water supply system comprises a water supply port and a water outlet; a water inlet of the two-stage low-temperature economizer communicates with the water supply port of the side water supply system; a water outlet of the two-stage low-temperature economizer communicates with a water inlet of theone-stage low-temperature economizer through a pipeline; and a water outlet of the one-stage low-temperature economizer communicates with the water outlet of the side water supply system. By means ofthe system, space is saved, a large amount of fuel gas waste heat at the tail of the boiler is recovered, and the dust removal rate of the dust remover and the efficiency of the desulfurizing tower are improved.

Description

technical field [0001] The invention relates to the technical field of industrial flue gas purification and waste heat recovery, in particular to a coal-fired boiler flue gas waste heat utilization system. Background technique [0002] With the rapid growth of China's national economy, the requirements for waste heat recovery of flue gas at the tail of industrial boilers in various regions are also growing rapidly. At the same time, the waste heat recovery equipment of flue gas is also being further improved. The development of waste heat recovery plays a vital role. [0003] Under the current form of energy saving and emission reduction, the secondary reheating technology of coal-fired units and the near-zero emission standard of flue gas have emerged as the times require. The standard stipulates that the emission concentration of smoke and dust should be less than 5-10 mg / Nm3. In order to meet this standard, low-temperature Electrostatic precipitator technology, that is, ...

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Problems solved by technology

[0004] The currently used low-temperature economizers are arranged between the air preheater and the ESP or after the induced draft fan. These two arrangements have high requirements on the size of the low-temperature economizer and have great limitations. For some boiler tail flue gas For those with higher temperature, due to the size limitation of the low-temperature economizer, it cannot meet the cooling requirements at all, and the cooling range is relatively low

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