给水加热型联合循环系统(火用)分析研究

根据我国传统火电厂的实际情况，研究探讨给水加热型联合循环更新技术对火电厂进行系统升级改造问题，该文在ASPEN PLUS模拟给水加热型联合循环系统基础上，采用图像Yong分析方法对给水加热型联合循环系统进行了深入的研究，揭示出引起循环系统Yong损失的内部现象，并提出了系统进一步改进的建设性方案，为传统火电厂的系统升级改造、方案设计提供了理论依据。

STUDY ON EXERGY EVALUTION FOR FEEDWATER HEATING COMBINED CYCLE SYSTEM

Based on repowering the existing coal - fired steam power plants in China, this paper investigates feed water heating combined cycle. Feedwater heating combined cycle system is simulated by using ASPEN PLUS software and its thermodynamic performance is evaluated and studied on the basis of graphical exergy analysis methodology. The exergy losses of heat transfer process and power process are mainly studied for feed water heating combined cycle system, and the distributions of exergy loss in those thermal processes are clearly identified. Some key points are found out to reduce exergy loss of internal system. As a result, the absolute thermal efficiency after repowering can be increased by 6.2 percentage points. Furthermore, we provide several feasible schemes for further system integration to improve the thermal efficiency of the combined cycle system. The results obtained here will provide theoretical basis for designing of repowering existing steam power plant from the viewpoint of system synthesis.