Exergy analysis of a gas-turbine combined-cycle power plant with precombustion CO2 capture
Exergy analysis of a gas-turbine combined-cycle power plant with precombustion CO2 capture
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DOI：
10.1016/j.energy.2004.05.029
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发表时间：
2005
期刊：
影响因子：
9
通讯作者：
I. S. Ertesvåg;H. Kvamsdal;O. Bolland
中科院分区：
文献类型：
--
作者：
I. S. Ertesvåg;H. Kvamsdal;O. Bolland
采用（火用）分析方法研究了天然气电厂CO2捕集的概念。天然气在自热重整器（ATR）中重整，分离出CO2后用于常规联合循环（CC）工艺。研究的主要目的是探讨重整过程和联合循环的集成。模拟了一个相应的传统CC电厂，没有CO2捕获的比较。带有CO2捕集的基本情况规定涡轮入口温度（TIT）为1250 °C，空气压缩机出口压力为15.6 bar。在这种情况下，净发电量为天然气低热值（LHV）的48.9%或其化学火用的46.9%。捕获和压缩的CO2（200巴）代表NG化学有效能的3.1%，而NG由于其压力（50巴）而具有等于其化学有效能的1.0%的物理有效能。研究了改变天然气组成和环境温度对天然气产率的影响。气体涡轮机和重整器中的较高压力增加了ATR中的燃烧并降低了总效率。研究了补充燃烧（SF）作为ATR加热的替代手段。这也降低了效率。用ATR的产物流加热ATR的进料被证明可以减少不可逆性并提高工厂的效率。研究了这两者以及将TIT增加到1450 °C的效果。结合这两种措施，净发电量增加到53.3%的NG LHV或51.1%的NG化学火用。另一方面，增加的TIT和ATR产物-进料热交换减少了烃向CO2的转化。
A concept for natural-gas (NG) fired power plants with CO2capture was investigated using exergy analysis. NG was reformed in an auto-thermal reformer (ATR), and the CO2was separated before the hydrogen-rich fuel was used in a conventional combined-cycle (CC) process. The main purpose of the study was to investigate the integration of the reforming process and the combined cycle. A corresponding conventional CC power plant with no CO2capture was simulated for comparison. A base case with CO2capture was specified with turbine-inlet temperature (TIT) of 1250 °C and an air-compressor outlet pressure of 15.6 bar. In this case, the net electric-power production was 48.9% of the lower heating value (LHV) of the NG or 46.9% of its chemical exergy. The captured and compressed CO2(200 bar) represented 3.1% of the NG chemical exergy, while the NG, due to its pressure (50 bar), had a physical exergy equal to 1.0% of its chemical exergy. The effects of the changed NG composition and environmental temperature were investigated. Higher pressure in the gas turbine and reformer increased the combustion in the ATR and reduced the overall efficiency. Supplementary firing (SF) was investigated as an alternative means of heating the ATR. This also reduced the efficiency. Heating the feeds of the ATR with its product stream was shown to reduce the irreversibility and improve the efficiency of the plant. Both this, and the effect of increased TIT to 1450 °C were investigated. Combining both measures, the net electric-power production was increased to 53.3% of the NG LHV or 51.1% of the NG chemical exergy. On the other hand, both increased TIT and the ATR product-feed heat exchange reduced the conversion of hydrocarbons to CO2.