催化学报

催化学报 ›› 2011, Vol. 32 ›› Issue (8): 1411-1417.DOI: 10.3724/SP.J.1088.2011.10416

• 研究论文 • 上一篇    下一篇

LaMO3 纳米复合钙钛矿氧载体化学循环重整甲烷制合成气

代小平*, 余长春   

  1. 中国石油大学 (北京), 中国石油天然气集团公司催化重点实验室, 北京 102249
  • 收稿日期:2011-04-12 修回日期:2011-05-16 出版日期:2011-08-05 发布日期:2014-12-26

Nano-Perovskite-Based (LaMO3) Oxygen Carrier for Syngas Generation by Chemical-Looping Reforming of Methane

DAI Xiaoping*, YU Changchun   

  1. Key Laboratory of Catalysis, China National Petroleum Corporation, China University of Petroleum, Beijing 102249, China
  • Received:2011-04-12 Revised:2011-05-16 Online:2011-08-05 Published:2014-12-26

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摘要： 采用溶胶-凝胶法制备了不同 B 位可变价离子的 LaMO3 (M = Cr, Mn, Fe, Co) 复合氧化物氧载体, 采用 X 射线衍射、N2 吸附-脱附、扫描电镜及 CH4 程序升温表面反应等手段对氧载体进行了表征, 并用于直接选择氧化 CH4 的反应中. 结果表明, Cr, Mn, Fe 和 Co 均能形成 LaMO3 纳米复合钙钛矿结构, 其氧物种氧化能力大小顺序为 LaCoO3 > LaMnO3 > LaFeO3 > LaCrO3. 在连续流动化学循环甲烷重整反应中, LaFeO3 中的氧物种具有更好的选择氧化性能 (H2/CO = 2.06), 其 CH4 转化率和 CO 选择性分别达到 89.6% 和 98.9%. 10 个连续顺序氧化-还原化学循环重整反应中, CH4 转化率约为 60%~70%, CO 选择性达 98% 以上; 且其结构保持了较高的稳定性.

关键词: 甲烷, 化学循环重整, 钙钛矿, B 位离子, 氧载体, 合成气

Abstract: Catalytic reforming of natural gas is a commercial process to produce syngas, which is the main source for the production of ammonia, methanol, hydrogen, and many other important products. This method produces also large amounts of CO2 as by-product. Chemical-looping reforming (CLR) is a novel technology that can be used for syngas production by partial oxidation and steam reforming of hydrocarbon fuels. One key issue with the CLR concept that is being widely studied is the oxidation and reduction behavior of potential oxygen-carrier materials. Four perovskite-based nano-composite oxides were prepared by the sol-gel method and characterized by X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy (SEM), and CH4 temperature-programmed surface reaction. The catalytic performance of the prepared samples for CLR of CH4 to syngas was investigated. The results showed that the LaMO3 (B = Cr, Mn, Fe, and Co) oxides possess perovskite-type nano-composite structure. The oxidizing ability of these four perovskite oxides follows the order of LaCoO3 > LaMnO3 > LaFeO3 > LaCrO3. Among them, LaFeO3 oxide has higher activity for CLR of CH4 to syngas. The CH4 conversion and CO selectivity are 89.6% and 98.9%, respectively. Especially, the sequential redox reaction revealed that the LaFeO3 oxide exhibits high stability with CH4 conversion of 60%~70% and CO selectivity of ~98% after 10 redox cycles. The SEM analysis revealed that the structure of the LaFeO3 oxide was not dramatically changed before and after 10 cyclic reactions.

Key words: methane, chemical-looping reforming, perovskite, B-site cation, oxygen carrier, syngas