Ni、Ce、Zn和Cu修饰Fe_(2)O_(3)/Al_(2)O_(3)载氧体的甲烷化学链制氢特性

Evaluation of Ni,Ce,Zn and Cu modified Fe_(2)O_(3)/Al_(2)O_(3)oxygen carriers for methane-fueled chemical looping hydrogen generation process

以甲烷为燃料的化学链制氢是一种耦合CO_(2)捕集的高效制氢技术。在Fe_(2)O_(3)/Al_(2)O_(3)载氧体的基础上,通过浸渍法分别添加Ni、Ce、Zn和Cu形成双金属载氧体,以提高其晶格氧传递性能、制氢性能和抗积炭性能。本文通过热力学计算、材料表征和实验研究,研究了不同双金属载氧体还原阶段和制氢阶段的反应性能,获得了不同双金属载氧体晶相结构与反应活性、制氢性能间的构效关系;并针对筛选出的最佳载氧体,进一步研究了其循环反应稳定性。研究表明,Cu是最合适的金属添加剂。Cu在Fe_(2)O_(3)/Al_(2)O_(3)双金属载氧体中形成了结构稳定的尖晶石相CuFe_(2)O_(4),提高了晶格氧活性,促进了载氧体中Fe_(2)O_(3)的深度还原,同时有效抑制积炭的生成,显著提高氢气产量和纯度,其中氢气产量由245mmol/100g载氧体提高到288mmol/100g载氧体,氢气纯度由88.3%提高到95.7%。Cu修饰Fe_(2)O_(3)/Al_(2)O_(3)载氧体在循环中表现出良好的稳定性,Fe^(3+)和Cu^(2+)的迁移使其微观结构得到改善,循环反应性能得到提高。研究验证了双金属载氧体在甲烷化学链制氢反应中的可行性,研究结果为铁基载氧体的设计和筛选提供了理论和实验依据。

Methane-fueled chemical looping hydrogen generation is an efficient hydrogen production technology coupled with CO_(2)capture.On the basis of Fe_(2)O_(3)/Al_(2)O_(3)oxygen carrier,Ni,Ce,Zn and Cu were added to form bimetallic oxygen carriers by impregnation method to improve the oxygen transfer performance,hydrogen production performance and carbon deposition resistance.Through thermodynamic calculation,material characterization and experimental study,the reaction properties of different bimetallic oxygen carriers in reduction stage and hydrogen production stage were studied,and the structure-activity relationship between crystal phase structure,reaction activity and hydrogen production performance of different bimetallic oxygen carriers was obtained.The stability of the cyclic reaction was further studied for the optimal oxygen carrier.Studies showed that Cu was the most suitable metal additive.CuFe_(2)O_(4),a spinel phase with stable structure,was formed in Cu-modified Fe_(2)O_(3)/Al_(2)O_(3)oxygen carriers,improving lattice oxygen activity,promoting the deep reduction of Fe_(2)O_(3),and effectively inhibiting carbon deposition.The yield of hydrogen increased from 245mmol/100g oxygen carriers to 288mmol/100g oxygen carriers,and the purity of hydrogen increased from 88.3%to 95.7%.The migration of Fe^(3+)and Cu^(2+)ions improved the microstructure and cyclic reaction performance.The feasibility of bimetallic oxygen carriers in methane-fueled chemical looping hydrogen generation was verified.The results provided theoretical and experimental basis for the design and screening of iron-based oxygen carriers.