燃煤机组烟气余热及水协同回收系统结构参数优化研究

Optimization on Structural Parameters of Fluegas Waste Heat and Water Recovery System in Coal-fired Power Plants

为了提高燃煤发电机组效率、降低机组水耗,本文针对烟气余热及水协同回收系统展开研究。该系统通过烟气换热器降低烟气温度至95℃,回收低温烟气余热的同时降低脱硫塔耗水量,并通过烟气冷凝器回收烟气中的水分,实现节能与节水的协同。本文研究了系统的运行特性,发现其有良好的节能节水潜力,同时研究了系统换热器面积及冷凝水质量流量对系统运行参数及性能的影响,发现低温省煤器、烟气冷却器、烟气再热器面积和低温省煤器冷凝水质量流量降低可以提高进入电除尘器烟气温度,为系统变工况运行调控、防止低温腐蚀提供指导。

To enhance the efficiency and reduce the water consumption of coal-fired power plants,the fluegas waste heat and water cooperative recovery system was studied in this paper.The system uses fluegas heat exchangers to reduce the fluegas temperature to 95℃,which can recover low temperature fluegas waste heat.Moreover,the water consumption of the desulfurization tower can be reduced,and the moisture in the fluegas can be recovered with the fluegas condenser.The system may achieve the synergy of energy and water saving.The operating characteristics of the system were studied,and results show that the system has a good potential for energy and water saving.Moreover,effects of the heat exchanger areas and the condensate mass flow rate on the operating parameters and performances of the system were studied.It is found that the decrease of area of low-temperature economizer,fluegas cooler,fluegas reheater and condensate water mass flow of low-temperature economizer can increase the temperature of the fluegas entering the electrostatic precipitator.The aim of this study is to provide some guidance for the control of system operation under off design condition and the prevention of low temperature corrosion.