Boiler flue gas waste heat recycling system

Abstract

The invention discloses a boiler flue gas waste heat recycling system. The boiler flue gas waste heat recycling system comprises a flue gas cooler high-temperature section device (3) and a flue gas cooler low-temperature section device (5). Flue gas exhausted from the boiler (1) sequentially passes through an air preheater (2), the flue gas cooler high-temperature section device (3) and a desulfurization system (6) and then enters a chimney (7) for being discharged; the flue gas cooler high-temperature section device (3) and the flue gas cooler low-temperature section device can reduce the temperature of the flue gas. According to the boiler flue gas waste heat recycling system, By means of a two-stage flue gas cooler, the waste heat of the flue gas of the boiler can be utilized in a staged mode, so that full energy saving can be achieve, and the problem of corrosion to flue gas coolers in the prior art can be solved, safety and reliability of a waste heat recycling system can be enhanced, the cost can be solved, and the working efficiency of the desulfurization system can be improved.

Description

technical field [0001] The invention relates to the technical field of boiler waste heat recovery, in particular to a boiler flue gas waste heat utilization system. Background technique [0002] The two major losses in thermal power plants are cold source loss and exhaust heat loss. The loss of cold source directly affects the heat efficiency of the cycle. For ordinary generator sets, the loss of cold source depends on the design parameters of the unit. The exhaust heat loss is the largest among all heat losses of power plant boilers. The exhaust heat loss of modern power plant boilers is generally about 4% to 8%. An important factor affecting the heat loss of exhaust gas is the exhaust gas temperature. According to statistics, in thermal power plants, the heat loss of boiler exhaust smoke accounts for 60% to 70% of the total heat loss of boilers. Every time the exhaust gas temperature rises by 10°C, the boiler efficiency will decrease by 0.6-1.0%, and the standard coal c...

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Problems solved by technology

Therefore, the design of the flue gas cooler needs to consider the prevention of low-temperature corrosion. However, the existing system has a low heat transfer temperature difference and does not recover much heat, resulting in a certain amount of energy waste.

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