Research On Economic Operation For USC1000MW Turbine Unit

This study is for air-cooling ultra-supercritical1000MW steam turbine, it is currently the world’s largest-capacity air-cooling unit. Under variable conditions of condensing steam turbine, the control stage enthalpy drop, the speed ratio and stage efficiency parameters change. This paper analyzes variable conditions theory of the control stage, the control stage characteristic curve calculating method and its application in variable working conditions in the practical is studied. After depth study of the variable conditions theory for steam turbine control stage, it simplifies the calculation of control stage efficiency on variable conditions of different turbine load. According to the characteristics of1000MW direct air-cooling unit, variable conditions characteristics of the condenser was analyzed. Using the mathematical model influence of the exhaust heat load, condenser inlet air temperature, wind speed and other factors to the condenser pressure was studied. Calculated and plot of various parameters-condenser pressure curves on different conditions. Humidifying spray device can obviously decrease the back pressure. In this paper the calculation of economic water amount for air cooling spray humidification system was carried out. Considering the variable conditions of the heater in heat recovery system, established the terminal temperature calculation model on variable conditions, calculated the influence of the changes of the heater terminal temperature difference to the economic operation of the unit. It provided the basis on further optimization for the same type of unit. With the help basic thermodynamic state of water and steam function, using MATLAB software, the calculation program for variable conditions is finished. On comparison of the heat loss correction curve divided by turbine manufacturer, on one same condition this calculated value can meet actual project demand, and then the accuracy of the calculation model in this paper is verified, so quick reference on heat consumption of the unit for local workers was provided.