A system that uses the low-temperature waste heat of the flue gas of the generator set to generate electricity

Abstract

The invention provides a system utilizing low-temperature smoke residual heat of a generator unit to generate power. The system comprises a first steam power generation system, a condensing water pipeline, a low pressure heater and a steam condenser, wherein the low pressure heater and the steam condenser are arranged on the condensing water pipeline, the first steam power generation system comprises a low pressure cylinder, a smoke residual heat recycling device and a second steam power generation system, the low pressure heater is connected with the low pressure cylinder, the smoke residual heat recycling device comprises a heat absorbing section and a heat releasing section, the heat absorbing section is arranged in a boiler flue, the heat releasing section is arranged on a condensing water branch pipe which is parallelly connected with the condensing water pipeline, the second steam power generation system comprises a second steam turbine and a second generator which are connected, the second steam turbine is connected with the low pressure cylinder through a steam suction pipe, and the low pressure cylinder and the second steam turbine are connected with the condenser through steam exhaust pipes. The system has the advantages that the low-temperature smoke residual heat can be safely recovered, the recovered residual heat is used for generating power again by the cascade utilization method, the traditional problem of inaccurate metering of the power generation by recovered residual heat is solved, the problem of low-efficiency utilization of low-temperature residual heat of large power plants is also solved, and the power plant can reach the energy-saving and environment-protection purposes.

Description

technical field [0001] The invention relates to the technical field of thermal power generation, in particular to a system for generating electricity by utilizing the low-temperature waste heat of flue gas from a generator set. Background technique [0002] Under the situation that the country vigorously advocates energy conservation and environmental protection and enterprises are developing themselves, the efficiency of boilers is getting higher and higher. Smoke temperature is one of the important indicators to measure boiler efficiency. The higher the exhaust gas temperature, the greater the exhaust gas loss and the lower the boiler efficiency. Therefore, the current exhaust gas temperature of boilers is lower. Now the exhaust gas temperature of large and medium-sized boilers is generally around 135 ° C, especially for large boilers. The air preheater is generally a rotary air preheater, so its exhaust gas temperature may be lower. [0003] Although the exhaust gas tem...

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Problems solved by technology

Due to the low exhaust gas temperature of the boiler, the grade of waste heat recovered by general waste heat recovery technology is low. In large-scale generating units, there is no suitable and effective utilization method. As a result, waste heat recovery projects cannot be used on large-scale generating units. This is also One of the main problems encountered in the low temperature waste heat energy saving of large generating units at present

Moreover, on large-scale generator sets, low-grade heat energy is relatively abundant. Therefore, can a large amount of low-grade heat energy be utilized through some technical solutions, and quantitative changes can cause qualitative changes, so that some higher-grade heat energy can be obtained. of heat energy, and effectively utilize this part of high-grade heat energy? This is the bottleneck encountered by the low-temperature flue gas waste heat energy saving of large-scale generating units. The main problem is not how to recover waste heat, but how to effectively use the recovered waste heat

[0004] The current general flue gas waste heat recovery technology uses waste heat to heat desalted water to reduce the extraction steam consumption of the low-pressure heater, so that the steam that does work in the steam turbine will increase, but due to the low grade of this part of steam, for large units The power generation efficiency of the steam turbine is low, and it affects the steam extraction balance of the boiler system. The saved steam extraction cannot be used efficiently, and the effective use of this part cannot be effectively measured, resulting in inaccurate energy saving. measurement

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