全回热超临界二氧化碳布雷顿联合循环特性及㶲经济性分析

Study on characteristics and exergo-economic analysis of completely recuperative supercritical carbon dioxide Brayton combined cycle

大量的废热损失和在中低热源应用下的低效率是影响超临界二氧化碳(supercritical carbon dioxide,S-CO_(2))布雷顿循环在可再生能源应用的重大挑战。为实现能量的高效利用,提出并分析了一种具有较好热源适应性的布雷顿联合循环系统。该系统通过集成预冷-锅炉耦合模块和吸收式发电/制冷耦合模块代替常规预冷器,可以完全回收预冷器的余热,通过多种工作模式,保证系统性能不受环境温度和季节变化的影响。研究结果表明:透平2入口温度、余热回热器1出口过热度和热端温差对系统分流比、能量输出和模块间耦合关系有显著影响;此外,由于不可逆性的改善和㶲损失的减少,中间换热器、透平1和发生器(含精馏塔)的㶲损失分别占比56.1%、6.9%和5.2%;优化后的热效率、㶲效率、产品㶲流成本和净输出功分别达到84.2%、74.1%、9.48美元/GJ和397.4 MW。

The exhausted heat losses in the PRC and inefficiency in medium and low heat source applications are significant challenges affecting the application of supercritical carbon dioxide Brayton cycle for renewable energy sources.To achieve efficient utilization,a precooler-free power/cooling combined system with superior heat source adaptability is proposed and analyzed.Integrating with the precooling-heating coupled module and the absorption power/cooling module instead of the PRC,the waste heat from the LTR is completely recovered,moreover,multiple operating modes ensure that the system performance unaffected by ambient temperature and seasonal changes.Parametric studies indicate that the TUR2 inlet temperature,the WHE1 outflow overheat degree,and the hot end temperature difference have significant effects on the Split Ratio,energy outputs,and the coupling relations among modules.Moreover,due to the improvement of irreversibility and the decrease of exergy losses,the three-largest exergy destructions occur in the IHE,the TUR1,and the RET+GEN,which account for 56.1%,6.9%,and 5.2%respectively.Furthermore,the optimized cases exhibit optimalηthermal,ηexergy,cP,total,and Wnet of 84.2%,74.1%,9.48 dollars/GJ,and 397.4 MW respectively.