用于固体氧化物燃料电池的煤基碳燃料研究

发布时间：2018-07-05 09:33

  本文选题：固体氧化物碳燃料电池 + 煤基碳燃料　； 参考：《山西大学》2015年硕士论文

【摘要】：煤是地球上储量最丰富、最廉价的化石能源,主要用于火力发电。传统的燃煤火力发电技术能量转换效率低,污染物排放量大,对环境造成了严重影响。固体氧化物燃料电池(SOFCs)能将煤高效、清洁地直接转换为电能,是新一代发电技术,对解决我国能源短缺和化石能源带来的环境污染问题具有重大的现实意义。适用于固体氧化物燃料电池的煤基碳燃料的制备技术是煤基燃料电池发电技术的重要组成部分,现阶段是制约其应用进程的重要因素之一。研究并阐明碳燃料的理化性质及其对燃料电池电化学性能的影响,对煤基碳燃料的制备具有重要的指导意义。物质的结构决定其性能。为了研究煤基碳燃料结构与其电化学性能之间的关系,本论文采用KOH化学活化法对煤基碳燃料的结构进行修饰,研究碳燃料的理化性质对其Boudouard反应性的影响,进而研究煤基碳燃料电池的电化学性能。本论文采用KOH法制备出三种不同比表面积的活性煤。研究发现,具有较大比表面积的碳燃料,一般有较高的Boudouard反应性,同时,碳燃料的微孔比表面积、孔径分布、表面含氧官能团、石墨化度等都是制约Boudouard反应性的重要因素。以2067m2g-1活性煤为燃料时,电池的开路电压(OCV)为0.877V,最大功率密度51 mW cm-2,碳利用率约是以煤为燃料时的6倍。本论文利用KOH法对冶金焦碳进行结构修饰,其碳微晶结构、微孔比表面积和含氧官能团等理化性质都得到显著改善,较大幅度地提高了Boudouard反应活性。以活性焦炭为燃料的OCV为0.97V,最大功率密度155 mW cm-2,碳利用率约是焦炭的6倍。结果表明,焦炭结构的改善对其电化学性能的提高起着重要作用。本论文在600℃左右热解煤制得半焦,并对半焦进行KOH法处理得到活性半焦。结果表明,半焦的电化学性能优于煤和焦炭。当以半焦为燃料时,电池的最大功率密度为43.5 mW cm-2,碳的利用率约是煤的2.4倍。因此,热解条件的优化是提高煤基碳燃料性能的一种重要手段。总之,研究表明,KOH法处理和结构修饰、热解处理条件的优化,对煤基碳燃料的理化性质和电化学性能具有显著的调控作用。具有较小的碳微晶结构、较大的微孔比表面积和较多的含氧官能团的碳燃料,表现出较高的Boudouard反应性和电化学性能。
[Abstract]:Coal is the earth's richest and cheapest fossil energy, mainly for thermal power generation. Traditional coal-fired thermal power generation technology has low energy conversion efficiency and large pollutant emission, which has a serious impact on the environment. Solid oxide fuel cell (SOFCs) is a new generation of power generation technology, which can convert coal into electricity directly and efficiently. It is of great practical significance to solve the problem of energy shortage and environmental pollution caused by fossil energy in China. The preparation of coal-based carbon fuel for solid oxide fuel cells (SOFC) is an important part of coal-based fuel cell (CFC) power generation technology, and it is one of the most important factors restricting its application at this stage. The physical and chemical properties of carbon fuel and its influence on the electrochemical performance of fuel cell are studied and expounded, which is of great significance for the preparation of coal based carbon fuel. The structure of matter determines its performance. In order to study the relationship between the structure of coal based carbon fuel and its electrochemical performance, the structure of coal based carbon fuel was modified by Koh chemical activation method, and the effect of physical and chemical properties of carbon fuel on its Boudouard reactivity was studied. Then the electrochemical performance of coal-based carbon fuel cells was studied. In this paper, three kinds of activated coal with different specific surface area were prepared by Koh method. It is found that carbon fuels with large specific surface area generally have high Boudouard reactivity. At the same time, the micropore specific surface area, pore size distribution, surface oxygen functional groups and graphitization degree of carbon fuels are all important factors that restrict Boudouard reactivity. When 2067m2g-1 active coal is used as fuel, the open circuit voltage (OCV) of the battery is 0.877 V, the maximum power density is 51 MW / cm ~ (-2), and the carbon utilization ratio is about 6 times higher than that of coal as fuel. In this paper, the structure of metallurgical coke was modified by Koh method. The structure of carbon microcrystal, the specific surface area of micropores and the oxygen functional groups were improved significantly, and the Boudouard reaction activity was greatly improved. The OCV of active coke as fuel is 0.97 V, the maximum power density is 155 MW cm-2, and the carbon utilization ratio is about 6 times of that of coke. The results show that the improvement of coke structure plays an important role in improving the electrochemical performance of coke. In this paper, char was prepared by pyrolysis of coal at about 600 鈩，

本文编号：2099765