基于实时稳态模型的汽轮机冷端系统闭环优化控制

摘要

汽轮机冷端系统是火电机组的重要辅助系统,其运行状态的好坏直接关系到机组的安全、经济运行.通过分析汽轮机冷端系统的换热机理,对汽轮机末级变工况计算模型、凝汽器换热变工况计算模型以及变频循环水泵变工况特性分析,建立汽轮机冷端系统最佳真空稳态计算模型,分析了机组在不同边界条件下的最佳运行真空,进而利用稳态计算模型构建最佳真空闭环优化实时控制系统,实现对机组循环冷却水流量的连续调节,提高了机组的运行经济性.%Cold-end system is an important auxiliary system of coal-fired power plant,which is directly effect on the safety and economic operation of the unit. In order to improve the operation economy,through the derivation of calculation model of turbine last stage,condenser and variable frequency circulating pump in the variation condition,the optimal vacuum calculation model is established. On basis of the steady state model,the optimal vacuum is calculated in the different unit load and ambient temperature,and then the closed-loop optimal control system of condenser vacuum is established,which can achieve continuous adjustment of the circulating cooling water flow and improve the operation economy of the unit.