Primary hot air heating system of secondary reheated fired coal power generation set

Abstract

The invention relates to a primary hot air heating system of a secondary reheated fired coal power generation set. The system comprises a second-stage extraction steam system of a steam turbine, wherein the second-stage extraction steam system of the steam turbine is connected to an external steam cooler and a primary hot air heater, separately, and extracted steam through the external steam cooler and the primary hot air heater is in joint connection to a second high pressure heater; four-stage extracted steam of the steam turbine is connected to the external steam cooler and the primary hotair heater, separately, and is in joint connection to a fourth high pressure heater through the external steam cooler and the primary hot air heater; a primary hot air inlet air duct is connected to an air pre-heater, and the primary hot air inlet air duct is connected to a primary hot air outlet air duct through two primary hot air heaters arranged in parallel; and a flow regulating valve on a water supply bypass of the external steam cooler can adjust the flow of water flowing through the external steam cooler. The system can improve the blending combustion proportion of a secondary reheatedfired coal boiler on high water and low heating value coal types, so that the variable load operating performance of the secondary reheating boiler is improved.

Description

technical field [0001] The invention relates to the technical field of coal-fired power generation, in particular to a secondary-reheat coal-fired generating set hot primary air heating system. Background technique [0002] At present, coal-fired generating units are still the main body of my country's power production and the basic guarantee for the long-term and stable development of my country's national economy. In recent years, double reheat technology has been gradually applied in the field of coal-fired power generation because of its cleanliness and high efficiency. However, in the thermal system of the double-reheat unit, the superheat of the extraction steam at each stage is relatively large, especially after the two-stage reheat, the superheat of the extraction steam is the largest, as high as about 300°C. In order to make full use of the superheat of the extraction steam and realize the cascaded utilization of the heat of the extraction steam, an external steam ...

AI Technical Summary

Problems solved by technology

However, when the primary air temperature is low and the output of the pulverizing system is to be ensured, it is necessary to increase the primary air rate, which will increase the resistance of the primary air system and easily cause overheating of the steam temperature.

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