Study Of High Back Pressure Heat Supply Of 300MW Cold Draw Condensing Unit In Jinqiao Power Plant

Under the new normal state of our country ‘s current economic development,the demond for electricity load of Inner Mongolia's Mengxi power grid is slowing down,the new situation of supply exceeds demand appears and it will be difficult to ease in the short time.In order to release the thermoelectric contradiction,it is urgent to explore the maximum heating capacity of the existing heating unit to become the top priority of the cogeneration unit.at the same time,the state vigorously advocates energy saving and emission reduction.The thermal power plant is listed as the key targetof energy conservation and emission reduction.so,it is necessary to heat up the steam turbine units with high back pressure,improve thermal efficiency,reducing coal consumption.This topic mainly studies the high back pressure heatingtransformation technology of the 300 MW cold draw condensing unitand the optimization selection of theoperation modeof the unit after the high back pressure heating transformation of the unit.and analyses the date of the unit test and operation combined with the reconstruction example of Jinqiao thermal power plant before and after the transformation and obtains the main data of the unit after the transformation.High back pressure heating is to reduce the vacuum degree of condenser,raise the pressure of exhausted gas,raise the temperature of cooling water,and make condenser become the heater of heat network.In this way,the latent heat of vaporization is fully utilized and the cooling water is heated directly to make it the circulating water of the heat network,thus reducing the loss of the cold source to zero,and improving the circulation heat efficiency.The Jinqiao thermal power plant is transformed into a "double back pressure double rotor exchange transformation".The double back pressure means that the condenser runs at different backpressure during heating and non heating periods,and the purpose of heating the circulating water of heating network is achieved by raising the back pressure.The dual rotor interchangeability is the high back pressure rotor after the last stage of the low pressure cylinder during the heating period.The pure condensing high efficiency rotor is used in the pure condensing condition.In the heating period,the circulating water medium of the condenser is used to run the four process of hot net circulating water,and the condenser is used as the first stage heater of the heat net circulating water,and the heat net circulating water is heated by the low pressure cylinder to supply the heating user for the heater of the first station.This paper takes the high back pressure of 300 MW unit of Jinqiao thermal power plant as the research object,first introduces the heating load and research background of Hohhot City,and then makes a comprehensive tracking to the normal operation of the high back pressure reconstruction design scheme of the #2 unit in Jinqiao thermal power plant,and makes a comprehensive observation and Analysis on the operation of the heating unit,and introduces the high level of the heating unit.The process of back pressure heating transformation is compared.The thermal economy before and after the transformation is compared,and the main economic indicators are listed.The economic operation plan of heating period after unit retrofitting is demonstrated,and reasonable economic operation mode is put forward.The cost and profit of project transformation are calculated.The high back pressure heating transformation of Jinqiao thermal power plant changed the original operation mode of the power plant,and realized a new heating mode combined with the wholesale and self-management,and put forward the reform of the high back pressure of the circulating water in the future thermal power plant.It provides reference and operation adjustment experience for actual transformation projects,and explores more economical heating and transformation methods based on actual operation test.