熔融碳酸盐直接碳燃料电池的机理模拟及性能多目标优化

Molten carbonate direct carbon fuel cell (MC-DCFC) has attracted extensive interests because it has the potential to achieve the efficient and clean applications of coal. The previously studies have showed that the anodic polarization loss is closely related to the carbon oxidation mechanism and that some of the performance parameters for evaluating the performance of MC-DCFC are restricted each another. Combined with the current experimental data observed, the present project will establish a new mechanism model for MC-DCFC by considering the anodic intermediate reactions such as elementary reactions of carbon (electro-) chemical oxidation, reversible Boudouard reaction, and CO electrochemical oxidation reaction. The multi-step reaction mechanism of oxidation anode into CO and CO2 will be clarified, the output performance of MC-DCFC will be quantitatively predicted, the influences of designing parameters and operating conditions on the performance of MC-DCFC will be revealed, and some new methods to effectively reduce the anodic polarization losses will be explored. Furthermore, a multi-objective optimization mathematical model which can make a compromise between more than one performance parameter will be established. By using the improved differential evolution algorithm, the optimum choices with a set of Pareto solutions will be provided for decision makers. According to the practical requirement of design, the personal optimum trade-off solution can be determined, and therefore, the designing parameters, operating conditions and load matching can be determined to make the MC-DCFC be globally optimized. The present project can provide some theoretical basis for prototype design and performance synthesis optimization of MC-DCFC.

熔融碳酸盐直接碳燃料电池（MC-DCFC）有望实现煤炭的高效清洁利用而得到广泛关注。既往研究表明：MC-DCFC的阳极极化损耗与碳氧化机制密切相关，评价其性能的某些参数相互制约。结合现有实验观测结果，本项目拟建立包含碳（电）化学氧化过程中的基元反应、逆Boudouard反应和CO电化学氧化反应等中间反应过程的MC-DCFC新机理模型，阐明碳多步骤（电）化学氧化成CO和CO2的反应机制，量化预测其输出性能，揭示各设计参数和工作条件对其性能的影响，探索有效降低阳极极化损耗的新方法。在此基础上，建立权衡兼顾多项性能指标的多目标优化数学模型，采用改进的多目标差分进化算法对MC-DCFC性能进行协同优化，获取多套优化方案供决策者选择。根据实际设计需要，从中选取个性化最优折中方案并确定MC-DCFC的设计参数、工作条件及负载的优化匹配。本项目可为MC-DCFC的原型化设计及性能综合优化提供理论依据。

熔融碳酸盐直接碳燃料电池（MC-DCFC）有望实现煤炭的高效清洁利用而得到广泛关注。既往研究表明：MC-DCFC的阳极极化损耗与碳氧化机制密切相关，评价其性能的某些参数相互制约。结合现有实验结果，从反应动力学出发，建立了阳极混合产物为CO/CO2的熔融碳酸盐直接碳燃料电池（MC-DCFC）新机理模型。模拟了工作条件及设计参数对碳燃料的（电）化学氧化行为的影响，弄清了阳极端Boudouard反应和物质间中间反应所扮演的角色。充分考虑电池内部各组件内微观传热传质过程中的不可逆损耗机制，获得了MC-DCFC多项性能参数的数学表式，模拟了主要工作参数和设计参数如工作温度、电流密度、固体碳颗粒尺寸等对电池各输出性能的影响。将模拟结果与结果进行对比，找出二者差异的原因，进一步完善了所建立的模型。通过推理阳极端碳燃料的反应机理，优化了阳极的几何构形和阴极微观结构，确定出不同性能指标下的最佳工况和合理工作区域，并找出制约MC-DCFC性能的因素，加深了对MC-DCFC阳极反应机理的认识。采用多目标优化方法，协同优化了MC-DCFC的整体输出性能。此外，理论推导了MC-DCFC内部释放的废热量，根据能量梯级利用的准则构建了以Stirling热机，二级半导体热电器等新颖废热回收利用耦合系统。数值计算表明所构建的新型耦合系统能有效地回收利用MC-DCFC内部释放的废热。上述研究成果发表于国际SCI期刊《Energy》、《International Journal of Hydrogen Energy》、《Energy Conversion and Management》上。所得成果可为实际MC-DCFC的优化设计和运行提供理论支持。