Economic Analysis And Realization Scheme Research Of Feed Water Pump Coaxially Driven By Turbine

With the development of industrial technology,the air cooling unit develops towards the supercritical and ultra-supercritical direction,which also promotes the development of boiler feed water pump technology.As the circulating flow equipment of driving working medium,the power of feed water pump increases with the increase of unit capacity.Because the energy consumption of electric driven feed water pump is huge,in addition,the back pressure of steam driven feed water pump is affected by external conditions,and the system is complex,the investment is large,so it is imperative to study a new feed water pump technology.Therefore,the configuration of feed water pump coaxially driven by turbine receives widespread attention.Firstly,based on equivalent heat drop method,the economic analysis model of steam driven feed water pump,electric driven feed water pump,as well as feed water pump coaxially driven by turbine configuration scheme is established,which including the internal power of steam turbine,electrical efficiency,heat consumption,coal consumption and auxiliary power consumption.Besides,the economic evaluation standard of boiler feed water pump system is established,and the standard mainly includes initial investment,annual power supply,auxiliary power consumption,coal consumption,annual profit and payback period of investment.Secondly,under the Turbine Heat Acceptance condition(THA),Turbine Rated load condition(TRL),Turbine Maximum Continuous Rating(TMCR)and the Valve Whole Open condition(VWO),the economic benefits of different boiler feed water pump configuration scheme are analyzed under 350MW,600MW and 1000MW unit.Compared with electric driven feed water pump configuration scheme,the initial investment of steam driven feed water pump and feed water pump coaxially driven by turbine are much higher,for the 350MW unit,under THA condition,the annual power supply of steam driven feed water pump and feed water pump coaxially driven by turbine increases by 0.42%and 0.31%,and the auxiliary power consumption decreases by 3.144%and 3.139%,in addition,the coal consumption decreases by 1.32g/(kW·h)and 0.98g/(kW·h),what's more,the annual profit increases by 5.082 million and 3.773 million yuan,respectively,which means that the economic benefits of steam driven feed water pump under 350MW is higher than other configuration scheme.And for 600MW unit,the annual power supply of steam driven feed water pump and feed water pump coaxially driven by turbine increases by 0.11%and 0.3%,and the auxiliary power consumption decreases by 3.18%and 3.19%,meanwhile,the coal consumption decreases by 0.36g/(kW·h)and 0.94g/(kW·h),and the annual profit increases by 2.376 million and 6.204 million yuan,respectively.For 1000MW unit,the annual power supply of steam driven feed water pump and feed water pump coaxially driven by turbine increases by 0.01%and 0.32%,and the auxiliary power consumption decreases by 3.12%and 3.14%,meanwhile,the coal consumption decreases by 0.03g/(kW·h)and 0.95g/(kW·h),and the annual profit increases by 33 thousand and 10.45 million yuan,respectively,which could conclude that every index of configuration scheme of feed water pump coaxially driven by turbine is better than that of steam driven feed water pump under 600MW and 1000MW unit.Afterwards,to analyze the implementation scheme of transmissions device for feed water pump coaxially driven by turbine,taking the speed control drive system of a typical 600MW/1000MW grade unit as an example,then the implementation of gearbox,coupling and speed control device,as well as the equipment selection of speed control system are discussed.The gearbox adopts the Forit BHS conventional parallel shaft gearbox to transmit power,and the coupling could use the membrane disk type and gear type to transmit torque,additionally,the speed regulating system is equipped with the star of speed control with better energy saving effect,and then the Programmable Logic Controller(PLC)control system is adopted to realize the control of the whole system.Finally,the installation of feed water pump coaxially driven by turbine is studied.And the difficulties in installation process,which including the overall arrangement structure,operating and monitoring system,the protection and adjustment system,as well as the effect of different equipment are mainly analyzed.This paper could provide theoretical guidance for the implementation of feed water pump coaxially driven by turbine in power plant.