摘要
根据分析理论,把锅炉、汽轮机及发电厂热力系统作为一个整体,通过对发电厂各环节进行分析找到具体损失环节并对具体位置提出改造方案,是发电厂改造的一种新方法。以某超超临界机组为例,运用分析理论找到损失环节,找到二次风温及给水温度对锅炉系统及电厂热力系统影响的关系,通过增加一级高压加热器提高给水温度,同时在保证锅炉排烟温度不变的前提下适当地提高二次风温,分析在给水温度及二次风温的双重作用下,锅炉乃至整个机组性能的变化。结果表明,当给水温度由299.5℃升高至322℃时,二次风温由327.8℃升高至360℃,锅炉系统传热损失由3 443 kJ/kg降低至3 254 kJ/kg,燃烧环节损失由6 204 kJ/kg降低至6 158 kJ/kg,锅炉效率由54.15%升高至54.45%,机组目的效率由42%升高至46.7%。
To perform an exergy analysis of various links in a power plant to find out a concrete loss link and to present a scheme for modifying a concrete position according to the exergy analysis theory with boilers,steam turbines and the thermal system of a power plant taken as a whole represents a new method for modifying power plants.With an ultra-supercritical unit serving as an example,the exergy analysis theory was used to find out the exergy loss link and the influence of the secondary air temperature and feedwater temperature on the boiler system and power plant thermal system.By adding a stage of HP heaters,the feedwater temperature was enhanced and in the meantime,by properly increasing the secondary air temperature under the precondition of maintaining the flue gas temperature of the boiler unchanged,analyzed was a change in the performance of the boiler and the whole unit under the dual action of the feedwater and secondary air temperature.The research results show that when the feedwater temperature increases from 299.5 ℃ to 322 ℃ and the secondary air temperature goes up from 327.8 ℃ to 360 ℃,the exergy loss of the heat conduction in the boiler system will go down from 3 443 kJ/kg to 3 254 kJ/kg,the exergy loss in the combustion link,drop from 6 204 kJ/kg to 6 158 kJ/kg,the exergy efficiency of the boiler,rise from 54.15% to 54.45% and the target exergy efficiency of the unit,increase from 42% to 47.7%.
出处
《热能动力工程》
CAS
CSCD
北大核心
2011年第3期310-314,372,共5页
Journal of Engineering for Thermal Energy and Power
关键词
分析
损失
目的效率
发电厂
锅炉
exergy analysis,exergy loss,target exergy efficiency,power plant,boiler
