基于熔融盐重整的有机固废电化学转化利用研究

The formation route and composition of organic solid waste (OSW) are quite complicated. It is essential to select the appropriate treatment technology for the utilization of OSW according to the actual situation. The electrochemical conversion and utilization of OSW was proposed based on the molten salt pre-reforming. The efficient and clean reuse of OSW was realized by using direct carbon fuel cell (DCFC) systems coupled with pyrolysis and molten salt reforming treatment. In detail, the reforming of components in the pyrolysis volatiles as well as the removal of contaminants were performed by means of molten salt pretreatment. Then, the chemical energy of the reformed volatiles was converted into electrical energy by using a direct carbon fuel cell. . This project is launched to illuminate the reaction mechanisms between the molten salts and the volatiles from the pyrolysis of OSW. And the removal efficiency of contaminants in the high-temperature molten salts is to be further investigated. Meanwhile, the thermochemical and electrochemical behaviors of volatiles’ containing components will be estimated in DCFC. And the anode reactions in DCFC will be described with the addition of tin (Sn), and the key influence factors of the electrochemical performance will be clarified. At last, efficient and clean conversion methods of OSW pyrolysis volatiles in DCFC will be established by molten salts reforming and Sn addition in the anode. The successful implementation of this project will provide fundamental support for the electrochemical utilization of OSW in DCFC, and also help to develop a new way to the efficient and clean utilization of MSW.

有机固体废弃物生成途径及组分复杂，根据现实情况选择合适的处理处置技术尤为重要。本项目提出的基于熔融盐重整的有机固废电化学转化利用新思路，耦合热解、熔盐重整及直接碳燃料电池多系统，借助熔盐预处理促进热解挥发份中污染物脱除与组分重整，利用直接碳燃料电池将重整后挥发份的化学能转化为电能，实现有机固废的高效清洁利用。本项目的研究旨在揭示有机固废热解挥发份熔盐热处理过程中的重整特性，阐释熔盐环境下多污染物的脱除作用机理；探讨典型挥发份组分直接碳燃料电池中的热化学和电化学转化行为，明晰阳极熔融锡的添加对改善燃料电池电化学性能及抗结焦性能的作用机制。最终，基于熔盐重整及阳极熔融锡的添加提升有机固废挥发份直接碳燃料电池电化学转化的利用效率。本项目的实施将为有机固废的直接电化学转化提供理论依据，为城市固体废弃物的高效资源化利用开辟新的途径。

我国有机固体废弃物能源化利用因成分复杂导致热利用技术复制性和规模化困难。本研究旨在探究有机固废挥发分与熔融盐的交互作用机理和关键影响因素、熔盐重整产物在Sn-SOFC阳极中的电化学转化机理、熔融金属阳极积碳生成机理及控制方法等。项目研究得主要结论如下：.本研究揭示了温度和不同熔盐体系对有机固废热转化的影响。相较于传统热解，通过K+的催化作用，以及NO3-参与到热反应之中，并通过熔盐较高的传热速率，一定程度上提高热反应速率，且随着熔盐的成分变化，生物质固废的热转化温度点也会发生变化；另外，NO2-的高反应活性显著促进了转化反应速率，并降低了固废热转化的反应温度，实验结果表明有机固废熔盐热处理是一种高效的资源化手段。.流量对热解气在Sn-SOFC中电化学转化性能影响十分有限，且流量进一步升高时，性能反而略有下降，这是由于在高流量下，热解气在Sn-SOFC阳极停留时间过短，热解气来不及电化学转化就被吹扫排出，进而导致峰值功率密度略有下降；当温度升高后，热解气、热解气及甲苯混合样品在Sn-SOFC中的极化性能会明显下降，这是由于高温下锡被氧化的速率明显提高，熔融锡阳极在电化学转化过程中会产生SnO2；此外，这些产生的SnO2不能被及时还原，导致了阳极SnO2聚集，覆盖了阳极表面活性位点，会显著限制燃料在阳极氧化的电子传输，导致转化性能下降。.另外，电池阳极中熔融锡对热解焦的C-CO2气化反应有着良好的催化作用，能从这一途径有效提高电池的电化学性能。引入了NO后，SOFC的极化阻抗下降，NO通过与模拟气的主要还原组分及沉积碳发生化学反应，影响阳极附近的电化学反应物浓度、阳极导电性能及气体扩散能力，综合效果是既提升了恒电压放电的电流输出，也保障了电池放电的稳定性。