Research On Feed Water System Optimization Design Of 350MW Upercritical Thermal Power Unit

With the advantages of supercritical power plant over conventional subcritical drum plant, such as higher efficiency, lower emissions, the supercritical units are becoming the major part in thermal power plant. However, the characters of strong multivariable coupling, highly nonlinearity and uncertainty make it difficult to operation and control, so it is meaningful and necessary to study the model and control algorithm of the supercritical power plant. Feed water system of supercritical thermal power unit is mainly studied in the paper, including process analysis、project improvement、modeling、parameter optimization and so on.The present paper took ChangChun 350 MW supercritical thermal power plant as an example to analyse the feed water process seriously. At present the feed water control strategy is mainly revised by intermediate point temperature and enthalpy, but the single control strategy exists drawbacks, so this artical proposed two improved feed water control system: one is combining the intermediate point temperature with enthalpy, the other is optimizing the spray desuperheating system. And they provided references for the field operation.Studying the supercritical power plant’s mathematical model is significant for better control of the thermal process. The model of feed water system was build under different load conditions based on modified partical swarm algorithm, then the author devised an adaptive PID controller based on formulas, and used the method to describe the load increasing of the supercritical unit.From the simulation results we can conclude that the adaptive PID algorithm based on formulas in this paper has better control quality and good robustness, and the method has a better control effect for the feed water system.