高分散ZrMg双组分钙基吸附剂的可控构筑及其生物质化学链气化制氢构效关系研究

Biomass-based calcium looping gasification (BCaLG) for hydrogen production has become a pioneering technology in the clean energy as the advantages of highly efficient hydrogen production, CO2 capture in situ, and highly intensive costs. However, during the process of the circulating fluidization and the high-temperature regeneration, the calcium-based sorbent is prone to structural collapse and sintering, which limits the development of BCaLG. This project will improve the performance of calcium-based sorbent by uniformly mixing the stabilizers and active components at the atomic scale and obtaining the best micro-morphology. Metal organic frameworks (MOFs) is used as precursor, and silica colloidal crystals are used as the template to construct ZrMg doped calcium-based adsorbent, which has advantages of the doped metals with the atomic scale dispersion, silica nanosphere supporting the pore structure, and having three-dimensional ordered mesoporous-macrostructure. Through advanced characterization technologies (EXAFS, XANES, et. al.), the relationships between calcium-based sorbent properties and atomic composition, electronic configuration, and pore structure will be revealed, and the active center strengthening mechanism and anti-sintering mechanism will be obtained by the theoretical calculation. Based on this, the structure-activity relationships between the calcium-based sorbent and the hydrogen production from the chemical looping gasification of biomass is also studied. Specifically, the catalytic cracking mechanism of the associated tar in BCaLG by calcium-based sorbent will be revealed. As well as, the glutinous bonding mechanism of alkali metals on the micro/nano scale structure of calcium-based sorbent will be studied. The effects of acid gas on the absorbing sites of calcium-based sorbent will also be discussed. These researches will provide some theoretical supports for the large-scale application of BCaLG.

生物质钙基化学链气化制氢技术因具有高效制氢、原位碳捕集及成本高度集约化等优点而成为清洁能源领域的先驱技术，然而在循环流化、高温再生等过程中钙基吸附剂易出现磨损及烧结等失活现象，这极大限制了该技术发展。本项目拟通过提高稳定剂与活性组分原子尺度的均匀混合及获取最佳微观形貌来提高钙基吸附剂的抗磨损及抗烧结性能。采用金属有机框架为前驱体，二氧化硅纳米球胶体晶体为模板，构筑具有掺杂金属原子级分散、二氧化硅纳米球支撑及三维有序介孔-大孔结构的ZrMg双组分钙基吸附剂。通过EXAFS、XANES等先进表征技术，揭示钙基吸附剂性能与原子组成、电子构型及孔结构之间的关系，并结合理论计算得到活性中心强化机理及抗烧结机制。基于此，研究钙基吸附剂与生物质化学链气化制氢之间的构效关系，明晰其对伴生焦油的催化裂解机理、碱金属粘结对其微纳结构的影响机制、酸性气体对其吸附位点的覆盖机制，为该技术规模化应用提供理论支撑。

生物质钙基化学链气化制氢技术因具有高效制氢、在线碳捕集及成本高度集约化等优点，而成为清洁能源领域的先驱技术。然而，在循环流化、高温再生等过程中钙基吸附剂易出现结构坍塌及烧结失活，这极大限制了该技术发展。依托本课题资助，开发了一套可快速切换碳酸化、煅烧温度及反应气氛、可自动记录的具有双温区的滑轨热天平系统，并在此系统上完成系列研究。除此之外，制备了10种新型钙基MOF衍生钙基吸附剂，通过实验研究，得到了一种高分散ZrMg双组分钙基吸附剂（Ca0.85Mg0.125Zr0.025-MOF-O），该吸附剂具有良好的初始吸附容量及循环稳定性，并从微纳层面、电子结构角度揭示高分散ZrMg双组分钙基吸附剂活性中心的强化机理及抗烧结机制，获得了高分散ZrMg双组分钙基吸附剂可控构筑原则和普适性制备策略；进一步，基于该钙基吸附剂，研究了其与生物质化学链气化制氢的构效关系，明晰了其对伴生焦油的催化裂解机理、碱金属粘结对其微纳结构的影响机制、酸性气体对其吸附位点的覆盖机制，为生物质钙基化学链气化制氢技术商业化应用提供了理论支撑。.通过本项目的资助，共计发表SCI论文16篇，申请发明专利1项。并通过与西安交通大学博导课题组合作辅助培养博士研究生1名，以及基于南方科技大学辅助培养硕士研究2名。本项目的研究为项目负责人后续科学研究打下了坚实的基础。