燃煤发电机组烟气余热回收系统优化与经济性分析

Optimization and Economic Analysis of Flue Gas Waste Heat Recovery System of Coal-Fired Power Plants

燃煤发电机组普遍存在着排烟温度过高的问题,为了降低排烟温度,回收烟气余热,烟气余热回收系统得到了广泛应用。以某国产典型660 MW机组为案例,设计了采用旁路烟道的烟气余热回收系统,建立了系统的热经济性与技术经济性分析模型,并针对系统的主要参数进行了优化。分析了不同参数下系统的热经济性指标,并对系统的技术经济性进行了计算。计算结果表明:采用旁路烟道的烟气余热回收系统的标准煤耗率降低了2.98 g/(kW·h),当机组在50%热耗率验收(THA)工况下运行时,系统的标准煤耗率降低了2.06 g/(kW·h)。系统总投资为981.8万元,年节煤净收益为812.7万元,系统投资回收期为1.21 a,在工程上具有可行性。

Coal-fired power plants generally have the issue of high exhaust flue gas temperature.In order to reduce the flue gas temperature and recover the flue gas waste heat,the flue gas waste heat recovery system has been widely applied in coal-fired power plants.With a 660 MW power plant as the reference case,the flue gas waste heat recovery system was designed with flue gas bypass,the thermal and technical economic analysis models of the system were developed,and main parameters of the system was optimized.The thermal economy indictors of the system under different parameters were analyzed,and the technical economy of the system was obtained.The calculation results showed that the standard coal consumption rate of the coal-fired utility using the flue gas waste heat recovery system was reduced by 2.98 g/(kW·h).When the unit is operated under 50%THA conditions,the standard coal consumption rate of the coal-fired utility using the flue gas waste heat recovery system was reduced by 2.06 g/(kW·h).The total investment of the system was 9.818 million yuan,the annual net income of coal saving is 8.127 million yuan,and the payback period of the system investment is 1.21 a,which showed that this system was feasible.