A kind of thermal power plant small turbine cascaded utilization of energy system and method

The present invention relates to a kind of thermal power plant small turbine cascaded utilization of energy system and method.There is shortcomings in steam feed pump system and steam-driven induced draft fan system at present.The system of the present invention includes that main steam turbine, main steam inlet tube, master enter steam control valve door, drive feed pump small turbine, feed pump connecting shaft and feed pump, it is characterized in: also include a steam inlet pipe, a regulation valve, a driving air-introduced machine small turbine, an air-introduced machine connecting shaft and an air-introduced machine, one end of a number steam inlet pipe is connected to drive on feed pump small turbine, the other end of this steam inlet pipe is connected on a driving air-introduced machine small turbine, and a regulation valve is arranged on a steam inlet pipe.The method comprise the steps that main steam turbine, only directly to driving feed pump small turbine to provide steam, drives the steam after part acting in feed pump small turbine, is more directly evacuated to air-introduced machine small turbine to drive small turbine to do work.The present invention can facilitate, effectively realize cascaded utilization of energy.