电站锅炉新型烟气余热回收技术及经济性分析

New Type of Technology of Flue Gas Waste Heat Recovery and Economy Analysis in Utility Boiler

为解决某300 MW火力发电厂循环流化床锅炉排烟温度偏高的问题,提出将传统低压省煤器与卧式相变换热器相结合的新型烟气余热回收技术。该技术不仅能预防换热设备酸腐蚀,还能实现电厂烟气深度余热回收节能。给出了系统的具体布置方案和设计参数,分析了系统对凝汽器真空以及引风机性能的影响,并应用等效焓降理论及节能定量分析理论进行理论计算。计算结果表明,采用该系统后,锅炉排烟温度降低45℃,降低标准煤耗近3.5 g/(kW·h)。

Considering the excessively high temperature of exhaust gas from CFB boiler in a 300 MW coal-fired power plant,a new type of technology of flue gas waste heat recovery was put forward,which was combination of traditional low pressure economizer and horizontal phase-changing heat exchanger.The technology not only can prevent acid corrosion of heat exchange equipment,but also can achieve energy saving deeply.The specific layout scheme and design parameters were given,the effect on condenser vacuum and the properties of induced draft fan were analyzed,and theoretical calculation were given using the equivalent enthalpy method and the theory of energy conservation.The results showed that by using this system the temperature of exhaust gas from boiler was lowered by 45℃,the consumption of standard coal was reduced by up to 3.5 g/（kW · h）.