Optimization Design Of Dynamic Parameter Monitoring For Direct Air Condensing Steam Unit

Under the new situation of national energy conservation and emission reduction and China’s special energy distribution,use of direct air cooling system in coal-fired power plants is an effective measure to resolve the contradiction between water and coal.However,in the long-term operation of the direct air-cooling unit,the hot air recirculation,the freezing of the winter tube bundle and the uneven heat transfer also affect the economic efficiency and safe operation of the coal-fired power plant.Therefore,this paper optimizes the dynamic parameter monitoring of the direct air condensing steam unit as the entry point,and conducts in-depth research by analyzing factors affecting the air temperature at the outlet of the air condenser and the development of the dynamic parameter monitoring device from the boiler side and the air side.1.The dynamic parameter monitoring technology of direct air-cooling system is currently relatively weak.Aiming at the study of outlet wind temperature characteristics,this paper proposes a BP air network based direct air condensing unit exit wind temperature prediction model.Taking the exhaust steam temperature,ambient temperature,unit load,condensate temperature,exhaust steam pressure and axial fan speed as model input,the outlet air temperature is used as the model output to study dynamic parameters of the direct air-cooling unit.Historical data of each factor is collected from the onsite DCS system.After the data is preprocessed,the BP neural network was used to establish the air temperature prediction model of the air condenser.Finally,verify the validity of the model by actually running the data.The model can predict the outlet air temperature of the air condenser under different working conditions,and provide the basis for the next step of developing the dynamic parameter monitoring technology,so as to arrange the position and quantity of the air condenser temperature measurement point reasonably,and the air condensation steam.The cleaning cycle of the device is a reference.2.According to the following theoretical research combined with professional learning,a set of devices for dynamic parameter monitoring of direct air condensation unit is designed and developed.Firstly,through the Solidworks software,a three-dimensional mechanical structure design with a ratio of 1:1 which includes the design of the shape and the drawing of the nonstandard parts is carried out,and the three-dimensional motion simulation is carried out to demonstrate the reliability of the mechanical structure.After a series of hardware selection,the SIEMENS SIMOTION D435 hardware platform is finally used to drive the servo motor via SINAMICS S120 as a drive for the measuring device.Sensors such as KIMO and SICK are used to monitor for temperature,wind speed,displacement,etc.In the host computer configuration,the development of the monitoring screen is mainly completed by GE’s Proficy HMI / SCADA-IFIX Chinese version software.And the communication between i FIX software and control software SIMOTION SCOUT is realized by OPC communication technology.Based on the historical data of 2×300MW direct air-cooling unit of a ameteorite power plant in Shanxi and combined with theoretical research and professional learning,this paper establishes a direct air-cooling condenser outlet wind temperature prediction model,and designs direct air condensation steam optimized.The unit dynamic parameter monitoring device provides a reference for the heat exchange performance of the same type of direct aircooling system,the optimization of dynamic parameters,and monitoring means.