Research On Heating Refrom Scheme Of N330 MW Unit

With the rapid development of the economy,people's demand for electricity and heat load has increased year by year.To this end,this paper takes a power plant N330 MW unit as an example,according to the idea of equivalent enthalpy drop,establishes a matrix model and calculates the variable working condition of the steam turbine.There is no complete model for the heating reforming scheme of adding the temperature reducing pressure reducer or the pressure matching device to the current unit,and the calculation formula of the steaming heating is given,which further improves the equivalent enthalpy of the steaming heating.The matrix model is applied to economic calculation of different electrical loads and different thermal load conditions,and the different transformation schemes are quantitatively studied.At the same time,considering the change of the working condition of the unit will lead to the change of the heater end difference and the exhaust steam pressure,and quantitatively analyze the change of the end difference of each heater and the change law of the condenser pressure after the working condition is changed.Based on the idea of equivalent enthalpy drop,according to the heating characteristics,the corresponding mathematical model is established to study the influence of the change of heater end difference and the change of exhaust steam pressure on the economics of the two heating reform schemes.The calculation results show that after the heat supply reform,the thermal performance of the unit changes,the heater end difference and the exhaust steam pressure are reduced correspondingly,the cold source loss is reduced,and the energy utilization rate is improved.However,the heating scheme with pressure matching device can fully consider the quality of steam,and realize the rational utilization of low-grade steam,and the standard coal consumption rate of power generation drops more.Moreover,under the condition of constant electric load,with the gradual increase of the amount of steam extraction,the trend of reducing the coal consumption rate of the power generation standard with the installation of the pressure matcher becomes more and more obvious.Under the condition of 100% THA,when the external steam supply heat is 75 t/h,the power consumption standard coal consumption rate of the retrofit scheme with the pressure matcher the standard coalconsumption rate of the installed temperature reducer is 5.6 g/(k W·h).Taking into account the economic changes caused by the change in heater end and exhaust pressure,the corresponding reduction is 0.1243 g/(k W·h)and 0.123 g/(k W·h).When the external steam extraction heat supply is 100 t/h,the power generation standard coal consumption rate of the retrofit scheme with the pressure matching device is 7.4 g/(k W·h)less than the standard coal consumption rate of the installed temperature reduction and pressure reducer,and will be heated.Considering the economic changes caused by the change of the end difference and the exhaust pressure,the corresponding reduction is 0.356 g/(k W·h)and 0.232 g/(k W·h).In addition,under the same working conditions,the total influence of the change of the end difference of each heater on the thermal economy of the unit is greater than the influence of the change of the exhaust pressure.This topic has certain guiding significance for the heating reform design of the same type of unit.