Aqueous-Alkaline/Carbonate Biocarbon Fuel Cell Development

CBET-0828006 Antal该项目的目的是开发一种碱性水/碳酸盐生物碳燃料电池，该电池通过利用在300 °C附近的温度下有利的电化学反应实现电解质不变性，同时表现良好。更广泛的影响。在生产生物乙醇和生物柴油燃料的过程中，会产生大量的木质纤维素残留物（如玉米芯、椰子壳）。这些残留物可以有效和快速地转化为生物碳。碳燃料电池可以从这些生物碳以及煤和其他化石碳中发电，理论热力学效率为100%。EPRI最近的一项研究表明，碳燃料电池具有将生物碳转化为电能的潜力，系统级效率约为60%，比目前最先进的整体气化联合循环（IGCC）或先进的粉煤发电系统实现的效率高出20%以上。因此，生物碳的生产可以补充生物质炼油厂中生物乙醇和生物柴油的生产，该炼油厂也以非常高的效率发电。其他影响包括两个BS和两个MS学生的培训，夏威夷太平洋大学（HPU）教师的参与，以及新的电化学工程课程材料的开发和纳入UH和HPU课程。鉴于夏威夷州不提供化学工程大学学位，这些影响具有特殊意义。智力上的优点。这个项目基于两个假设。1)在接近300 °C的温度下，碱性水溶液/碳酸盐生物碳燃料电池将提供约1 V的开路电压（OCV）和超过100 mW/cm 2的稳定最大功率密度。2)在操作期间，电解质的组成将朝向氢氧根离子和碳酸根离子的平衡混合物演变，该平衡混合物之后将是不变的（即稳定的）。这种电池的阴极类似于培根燃料电池的阴极，空气中的氧气在银催化剂上被还原为氢氧离子。热力学分析表明，阴极在接近300 °C的温度下应该表现良好。同样，热力学分析表明，在这些温度下，氢氧离子和碳酸根离子（由CO2与氢氧离子反应形成）都应该剧烈氧化碳阳极并释放电子;从而以高效率发电。该项目有三个目标：1）表征阳极炭在接近300 °C的燃料电池水-碱/碳酸盐环境中的氧化行为; 2）表征电解质的稳定性，以及不同电解质在接近300 °C的温度下对阳极和阴极反应的催化作用;以及3）表征生物碳阳极在包括反电极的装置中作为工作电极的性能，以及电解质通过热交换器桥流到保持在系统压力但在低得多的温度下的参比电极。

CBET-0828006AntalThe aim of this project is the development of an aqueous-alkaline/carbonate biocarbon fuel cell which performs well while realizing electrolyte invariance by exploiting electrochemical reactions that are favored at temperatures near 300 °C. Broader impacts. Very large quantities of lignocellulosic residues (e.g. corncobs, coconut shells) accompany the production of bioethanol and biodiesel fuels. These residues can be efficiently and quickly converted into biocarbons. Carbon fuel cells can generate electricity from these biocarbons -as well as from coal, and other fossil carbons-with a theoretical thermodynamic efficiency of 100%. A recent EPRI study indicates that carbon fuel cells have the potential to convert biocarbons into electrical power at a system level efficiency of about 60%, which is over 20% higher than the efficiencies realized by current state-of-the-art integrated gasification combined cycle (IGCC) or advanced pulverized coal power generation systems. Thus the production of biocarbon can complement the production of bioethanol and biodiesel in a biomass refinery that also produces electricity at a very high efficiency. Other impacts include the training of two BS and two MS students, the involvement of Hawaii Pacific University (HPU) faculty, and the development and inclusion of new electrochemical engineering course material in the UH and HPU curricula. In view of the fact that a college degree in chemical engineering is not offered in the State of Hawaii, these impacts have special significance. Intellectual merit. This project is based on two hypotheses. 1) At temperatures approaching 300 °C the aqueous-alkaline/carbonate biocarbon fuel cell will offer an open circuit voltage (OCV) of about 1 V and a steady, maximum power density that exceeds 100 mW/cm2. 2) During operation the composition of the electrolyte will evolve towards an equilibrium mixture of hydroxide and carbonate ions that afterwards will be invariant (i.e. stable). The cathode of this cell resembles that of a Bacon fuel cell, where oxygen in air is reduced to hydroxide ion over a silver catalyst. Thermodynamic analyses indicate that the cathode should perform well at temperatures approaching 300 °C. Likewise, thermodynamic analyses indicate that at these temperatures both the hydroxide ion and the carbonate ion (formed by the reaction of CO2 with hydroxide ion) should vigorously oxidize the carbon anode and release electrons; thereby generating power at high efficiency. This project has three objectives: 1) to characterize the oxidation behavior of anodic char-coal in the aqueous-alkaline/carbonate environment of the fuel cell at temperatures near 300 °C; 2) to characterize the stability of the electrolyte, together with the catalytic effects of differing electrolytes on the anodic and cathodic reactions at temperatures near 300 °C; and 3) to characterize the performance of the biocarbon anode as a working electrode in a setup that includes a counter electrode, and flow of the electrolyte through a heat exchanger bridge to a reference electrode maintained at system pressure but at a much lower temperature.