Performance Monitoring And Optimization Of The Steam-Driven Induced Draft Fan Of Large Thermal Power Unit

Induced draft fan is one of the most important auxiliaries of coal-fired boiler of large power station, as well as one of the biggest consumers of auxiliary power. The steam-driven induced draft fan which uses steam turbine as driving mechanism of induced draft fan instead of high power electric motor, can reduce auxiliary power ratio significantly. The variable speed adjustment of the small steam turbine makes the induced draft fan work in the high efficient area all the time, which reduces the energy consumption further. However, due to the short operation time and insufficient accumulation of technologies, some problems such as energy saving effect, running characteristics and the way of regulating of the steam-driven induced draft fan, have not been solved. So, some researches based on a steam induced draft fan system of 600 MW unit in Shanxi Province are maken in this paper, which can be listed below:According to the theory of energy value and the analysis method of the power supply coal consumption, the economic efficiency and energy saving effect of the steam-driven induced draft fan are evaluated in this paper.In order to explore the operating characteristics of steam-driven induced draft fan system, a calculation model of the steam-driven induced draft fan which can calculate the characteristics of all the working conditon is established, including the characteristics model of induced draft fan based on the LS-SVM algorithm, the pipeline resistance model based on data fitting method and steam consumption calculation model of the small steam turbine.Based on the operating characteristics, the optimal operation which can make the steam-driven induced draft fan run both safely and efficiently is sdutied in this paper. An optimization control strategy that the blade angel and rotation speed of the induced draft fan should be changed coordinately and the blade angle should be changed over load is put forward, according to the actual situation of target power plant.In order to guide the operation of the power plant specificly, all the research achievements of this paper are integrated to develop the optimal operation software system, which includes four function modules, online monitoring, optimizing operation, safety warning and offline guide. The software system can make comprehensive guidance to the operation of steam-driven induced draft fan.