Characteristics Research Of Water Coal Ratio In Supercritical Unit

With the deepening of power industry reform power generation enterprises are facing unprecedented opportunities and challenges. Supercritical unit continues to show its advantages, it not only has the incomparable efficiency, at the same time due to its minimum thermal inertia, boiler start-up time is short, variable load faster, it can meet the requirements of peak load regulation of power grid. So it Is the future development direction of large unit.Characteristics of The Once-through Unit are introduced, focuses on the working mechanism of once-through boiler water system, as well as the once-through boiler main steam temperature and water supply control mode, emphasize the importance of water coal ratio in once-through unit By analyzing the energy balance and material balance relationship of water system, then with a method which is being proposed for calculating the heat release concerned, by means of a boiler’s known amount of air flow, together with the oxygen content in the flue gas, the steady state water coal ratio model is developed. And according to the data of ZouXian 1000MW supercritical power plant unit under various loads verify the model.Through the mechanism analysis, divided the Once-through unit into three parts, Establish a simplified model of the unit, and according to field data to identify various parameters of the model, builds a simulation model in simulink components, do the open-loop step disturbance experiment of the model, according to the coal pulverizing system and system dynamic characteristics, Analysis water coal ratio dynamic characteristics when the unit load changes. Through analysising the mechanism of the pulverizing system, combined with the unit model, derived the unit dynamic compensation link, Artificially slow down the feed speed of the water, to achieve a dynamic stabilization of the unit coal-water ratio, Thus ensuring the separator outlet steam enthalpy stability.