Simulation-based State Monitoring And Operation Optimization Of Thermal Power Units

With the increasing requirements for energy conservation and emission reduction,real-time monitoring and operation optimization of thermal power units have become the key to improving the operating efficiency of thermal power units.It is of great engineering value to carry out relevant research.In this paper,taking 600 MW subcritical thermal power unit as the object,both static and dynamic simulation models are built including the boiler side(including furnace,water wall,superheater,reheater,primary air system,secondary air system,economizer,etc.)and steam turbine side(including steam turbine body,Condenser system,feed water heater system,deaerator system,etc.).The dynamic simulation model of the unit is established by APROS,and the static simulation model of the unit is established by EBSILON.Based on this,the following research work is carried out:1.Firstly,the constant pressure operation model and sliding pressure operation model of the unit are established on the basis of the EBSILON static model,and the exergy analysis of the steam turbine is carried out according to the two models,the overall exergy efficiency and exergy loss of the steam turbine are calculated,and the exergy loss and exergy efficiency of each single cylinder are calculated.Comparing the exergy analysis of the steam turbine under two different operating modes of constant pressure operation and sliding pressure operation,the exergy efficiency of the steam turbine in the sliding pressure operation mode is higher than that in the constant pressure operation mode.2.Among the many operating control parameters,the initial operating pressure(main steam pressure)of the unit is one of the key factors affecting the heat consumption rate of the steam turbine,and it is also one of the most important operating parameters in the steam turbine.Therefore,the optimization of the initial pressure parameters of the steam turbine unit operation is a main content of the steam turbine operation optimization.In this paper,the initial pressure is optimized with the minimum heat consumption rate as the goal.After optimization,the heat consumption rate is reduced accordingly,and the overall exergy efficiency of the steam turbine is improved under different working conditions.Among them,the overall exergy efficiency of the steam turbine increased by 0.4175%,0.3677%,0.4475%,and 0.5527% under the working conditions of 90% THA,75% THA,50% THA,and 40% THA,respectively,and the exergy loss of each single cylinder was reduced.The exergy loss of the high-pressure cylinder is reduced to the greatest extent,and the reductions are 9721.91MJ/h,6905.006 MJ/h,4090.148 MJ/h,and 6219.181 MJ/h under the conditions of 90%THA,75% THA,50% THA,and 40% THA,respectively.3.On the basis of the static model,by determining the linear relationship between the pressure drop of the steam extraction pipeline and the mass flow rate and volume flow rate,and correcting the EBSILON model by fitting the heat transfer characteristic curve KA-M of each heater,the operation of the steam turbine side is carried out.The calculation of the parameter target value mainly includes the target value of the steam extraction pipeline pressure loss,the target value of the heater end difference,and the target value of the feed water temperature.Comparing the calculation results with the design data confirms that the calculation results of the simulation model are true and reliable.The EBSILON static model is used to analyze the consumption difference of the unit,and analyze the change of the heat consumption rate when each single thermal parameter changes.4.In this paper,a coordinated control system model with the strategy of boiler following steam turbine is established,and simulation experiments of constant pressure operation and sliding pressure operation are carried out.The dynamic model established by APROS is used to simulate the actual unit operation on site,and MATLAB is developed as a data interaction tool.The data interaction between the APROS model and the EBSILON static model is realized by using the OPC technology and the dynamic link library technology(calling the dll file)respectively.The static model of the unit established by EBSILON is used as the condition monitoring and performance index calculation platform of the unit to realize the co-simulation of the APROS model and the EBSILON model.5.Finally,the APROS simulation model conducts simulation experiments according to the sliding pressure curve before optimization and the sliding pressure curve after optimization of the EBSILON model,and compares the heat consumption rate of the two processes.The test results show that the optimized sliding pressure operation has a lower heat consumption rate,which verifies the reliability of the optimized results and provides a reference and support for guiding the actual operation in the field.