Method for improving temperature of smoke discharged by chimney of thermal power plant, smoke heating system and thermal power generation unit

Abstract

The invention discloses a method for improving temperature of smoke discharged by a thermal power plant, a smoke heating system and a thermal power generation unit adopting the system. The method utilizes waste steam of a driving steam turbine to heat the smoke passing through and flowing out of a desulfurizing absorption tower, and then heated smoke is discharged into a chimney. The smoke heating system comprises a smoke heating device which is arranged between the desulfurizing absorption tower and the chimney and used for utilizing the waste steam of the driving steam turbine to heat the smoke. The smoke heating system fully utilizes the waste steam energy of the driving steam turbine, especially latent heat of vaporization in the waste steam, the overall efficiency of the thermal power plant is improved, meanwhile the smoke rising height is increased, the pollutant falling concentration is reduced, and environmental protection is facilitated.

Description

technical field [0001] The invention relates to thermal power generation, in particular to a flue gas heating system in power generation equipment. Background technique [0002] After a thermal power plant is equipped with a wet desulfurization system, the temperature of the flue gas passing through the desulfurization device is generally 50°C. Some desulfurization systems are equipped with a flue gas-flue gas heat exchanger (GGH), which can increase the temperature of the flue gas to about 80°C, and then discharge it to the atmosphere through the chimney. Without the GGH desulfurization system, the temperature of the chimney discharge is only about 50°C. After wet desulfurization, the flue gas at 50°C contains more water, which will cause the following problems: (1) The corrosiveness of the flue gas at 50°C is much higher than that at 80°C, so that the chimney must use expensive corrosion-resistant materials; (2) The high water content of the flue gas will cause the gypsu...

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Problems solved by technology

After wet desulfurization, the flue gas at 50°C contains more water, which will cause the following problems: (1) The corrosiveness of the flue gas at 50°C is much higher than that at 80°C, so that the chimney must use expensive corrosion-resistant materials; (2) The high water content of the flue gas will cause the gypsum particles to be discharged from the chimney and fall in the area around the chimney, causing "gypsum rain" and affecting the environment of the power plant

However, since both auxiliary steam and hot secondary air can be used for power generation, the energy is high-quality energy. Consuming auxiliary steam and hot secondary air will consume a lot of energy and reduce the overall thermal efficiency of the power plant

[0004] At present, in the power plant, the exhaust steam driving the steam turbine is discharged into the condenser, and most of its energy is taken away by the circulating water, which cannot be utilized by the power plant.

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