论文部分内容阅读
联合应用空气预热器旁通烟道与暖风器回收电站锅炉排烟余热,可使锅炉尾部烟气热能与汽轮机回热系统间的交叉梯级利用更优,获得更高的电厂效率.以某600 MW超超临界燃烟煤机组为例,对旁通烟道与暖风器联合系统进行了热经济性与技术经济性分析,作为比较对常规旁通烟道系统也进行了计算.结果表明,由联合系统回收锅炉排烟从122℃降温至90℃的余热,使机组供电标准煤耗减小4.26g/(kW·h),需投资1500万元,动态投资回收期1.73年;而应用常规系统时上述结果分别为:2.63g/(kW·h)、1685万元和3.56年.可见联合系统具有明显的热经济性和技术经济性优势,建议对其进行工程化应用研究.提高暖风器出口温风温度可提高联合系统热经济性,但技术经济性结果变化很小,故温风温度不宜过高.“,”For a more efficient power generation of thermal power plants,an improved bypass flue process was proposed in this paper to recover the exhaust gas heat at the boiler cold-end.In comparison with the conventional bypass flue process,the improved process,which integrates a condensate air heater into the bypass flue process,achieves a better crosswise and stepwise utilization of the flue gas heat via the heat regenerative system of steam turbines.To demonstrate the thermal economy and techno-economic performances of the proposed process,an in-service 600MW hard-coal-fired ultra-supercritical power unit was used as the reference unit for analyses;meanwhile,the corresponding performances of the conventional process were also calculated for comparison.The results show that,with the recovery of boiler exhaust heat from 122℃ to 90℃,the improved process can make the net standard coal consumption rate of the unit reduced by 4.26 g/(kW.h) in comparison with the reference unit,with the capital cost of 15 million CNY for the heat recovery project and the dynamic investment payoff period of 1.73 years.Correspondingly,the results of the conventional process are 2.63 g/(kW·h),16.85 million CNY and 3.56 years.It indicates that the improved process has an obvious thermal economy and techno-economic advantage over the conventional process,thus this paper recommends it for a preferential application.In addition,for the improved bypass flue process,increasing the air temperature at the condensate air heater outlet can better the thermal economy,while it shows a neglectable effect on the techno-economic results.Therefor,e,it is not necessary to select an excessively high warm air temperature for engineering application.