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An improved supercritical coal-fired power generation system incorporating a supplementary supercritical CO2 cycle
Applied Energy ( IF 11.2 ) Pub Date : 2018-09-18 , DOI: 10.1016/j.apenergy.2018.09.122
Cheng Xu , Qiang Zhang , Zhiping Yang , Xiaosa Li , Gang Xu , Yongping Yang

Large superheat degree of the steam bleeds from regenerative heaters as well as the large heat transfer temperature difference during the air preheating process is not thermodynamically satisfactory in advanced supercritical power plants with the aim of high power generation efficiency. In this study, an improved supercritical coal-fired power generation system, which integrates a supercritical CO2 (S-CO2) power cycle to utilize the superheat of the steam bleeds as well as to heat the combustion air, was proposed. In the proposed system, the heat transfer temperature difference within the steam regenerative trains and air preheating process could be reduced, leading to less exergy destructions. Moreover, less required heat for flue gas air heaters makes it possible to adopt a low-temperature economizer (LTE) between the arranged two-stage flue gas air heaters, saving part of the steam bleeds, even if the exhaust flue gas temperature is kept constant. The detailed exergy distributions within the regenerative heaters and air pre-heating process were discussed using the graphical exergy analysis. The mass and energy balance of the proposed system and the overall system performance were determined using the process simulation. The economic viability and the implementation feasibility of the proposed system was also analyzed. Results showed that the exergy destruction of the regenerative heaters and air preheating process could be reduced by 4.47 MW and 11.95 MW, respectively. The gross electric power output from the proposed system was 1007.79 MW with a satisfactory energy efficiency at 46.0%, 0.4 percentage point higher than the reference power plant. The payback period of the proposed system is slightly longer than that of the reference plant at the current market condition and it will be more profitable as the S-CO2 cycle becomes more commercially mature.



中文翻译:

一种改进的超临界燃煤发电系统,结合了辅助超临界CO 2循环

在先进的超临界发电厂中,以高发电效率为目标,在热力学上不能令人满意地从再生加热器中排出的蒸汽的过热度大,以及空气预热过程中的传热温差大。在这项研究中,改进的超临界燃煤发电系统集成了超临界CO 2(S-CO 2提出了利用蒸汽放气的过热以及加热燃烧空气的动力循环。在所提出的系统中,蒸汽再生列车和空气预热过程中的传热温差可以减小,从而减少了火用的破坏。此外,烟气空气加热器所需的热量更少,因此即使在保持烟气温度不变的情况下,也可以在布置的两级烟气空气加热器之间采用低温节能器(LTE),从而节省一部分蒸汽排放持续的。使用图形的火用分析讨论了蓄热式加热器和空气预热过程中的详细火用分布。使用过程仿真确定了拟议系统的质量和能量平衡以及整个系统的性能。还分析了该系统的经济可行性和实施可行性。结果表明,再生加热器的火用破坏和空气预热过程分别可以减少4.47兆瓦和11.95兆瓦。拟议系统的总电力输出为1007.79兆瓦,能源效率达到46.0%,比参考发电厂高0.4个百分点。在目前的市场条件下,拟议系统的投资回收期比参考工厂的投资回收期略长,并且作为S-CO可以更有利可图 拟议系统的总电力输出为1007.79 MW,能源效率为46.0%,比参考发电厂高0.4个百分点。在目前的市场条件下,拟议系统的投资回收期比参考工厂的投资回收期略长,并且作为S-CO可以更有利可图 拟议系统的总电力输出为1007.79 MW,能源效率为46.0%,比参考发电厂高0.4个百分点。在目前的市场条件下,拟议系统的投资回收期比参考工厂的投资回收期略长,并且作为S-CO可以更有利可图2个周期变得更加商业化。

更新日期:2018-09-18
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