基于酮类平台化合物的生物质定向热解-集成缩合加氢制备航空燃油的机理研究

Jet fuel production from biomass has been one of hot research directions in energy field. Considering that the objective products of several current technologies of jet fuel production from biomass were only linear alkane , this project proposes a new idea that takes ketones from biomass directional pyrolysis as platform chemicals and then ketones are converted into linear and cyclo alkane mixtures by integrated adol condensation and hydogenation. Based on this idea, in-situ DRIFTS and quantum chemistry calculation are firstly combined to reveal the directional conversion mechanism of several components of biomass pyrolysis vapor, and the structure-activity relationship of catalysts in biomass directional pyrolysis is studied. Then the reaction mechanism of carbon chain growing and cyclization is investigated in the integrated reaction, and compound compatibility between metal for hydrogenation and acid/alkaline metal oxide for condensation of bifunctional catalysts is explored. Finally, the synergistic mechanism between dictional pyrolysis and integrated adol condensation and hydrogenation is revealed, and also a neural network model is built between characteristic parameters of jet fuel and biomass types, reaction condition and catalysts, which realizes macro regulation of jet fuel property. By this study, theoretical foundation will be formed for jet fuel production by biomass directional pyrolysis followed by integrated condensation and hydrogenation with ketones as platform chemicals.

利用生物质制备航空燃油已成为能源领域的热点研究方向之一。针对目前诸多生物质制备航空燃油技术目标产物仅为链烷烃这一问题，本项目提出一条以生物质定向热解所得酮类作为平台化合物，经羟醛缩合加氢集成反应转化为链烷烃和环烷烃混合物的新思路。基于此思路，首先采用原位红外试验与量化计算相结合的方法，揭示生物质热解气多组分的定向转化机理，探索生物质定向热解中催化剂构效关系；然后研究集成反应中碳链增长和环化过程的反应机制，探索双功能催化剂中加氢金属与缩合酸/碱性金属氧化物的复方配伍关系；最后揭示定向热解与羟醛缩合-加氢集成反应的协同作用机理，建立生物质类型、反应工况、催化剂等与航空燃油特性参数之间的神经网络模型，实现航空燃油性质的宏观调控。通过研究，基本形成基于酮类平台化合物的生物质定向热解-集成缩合加氢制备航空燃油的理论基础。

利用生物质制备航空燃油已成为能源领域的热点研究方向之一。针对目前诸多生物质制备航空燃油技术目标产物仅为链烷烃这一问题，本项目提出一条以生物质定向热解所得酮类作为平台化合物，经羟醛缩合和加氢集成反应转化为链烷烃和环烷烃混合物的新思路。.生物质定向热解制备酮类平台化合物方面。探究了生物质热解气多组分定向催化转化为酮类的反应机理。生物质热解气模化物在酮化过程中整体呈现出一条链状路径，即醇→醛→酸→酮；发现乙酸的存在会促进正丁醛的酮化，而糠醛的存在会抑制乙酸的酮化。通过TG-GC/MS分析发现，甘蔗渣在热解过程中产生了最多的酮类物质（33.68%）和可酮化物质；通过海水浸泡引入适量的金属元素可以有效地提高酮的产率。使用原始赤泥为催化剂，对热解温度和酮化温度合理匹配；赤泥催化剂上负载金属氧化物二氧化铈，酮类总产率得到有效提高；为了控制催化剂的氧化性，赤泥负载两种金属氧化物CeO2和MnO2，酮类总产率达到30.12%。.酮类平台化合物缩合加氢集成反应方面。以生物质定向热解产生的环戊酮作为平台化合物，Mg/Al比为3:1的Mg-Al-O作为缩合反应催化剂，Ni/γ-Al2O3作为加氢催化剂，目标烷烃的产率最高达到83.79%。然后探索双功能催化剂中加氢金属与缩合酸/碱性金属氧化物的复方配伍关系，Mg-Al-O由于具有较多的弱、中等碱性位点被选为缩合催化剂，Ni是加氢催化剂的最佳选择，采用活性炭共沉淀法制备了Ni/Mg-Al-O/AC，优化Ni负载量20wt %、煅烧温度500 °C和活化温度500 °C，目标烷烃的最大产率可达81.1%。为优化一锅制备航空燃油体系，在有机溶剂体系下设计双功能催化剂及采取一步法低温缩合-高温加氢策略，催化剂经5次使用后催化性能良好，环戊酮转化率和目标烷烃的产率稳定在94.7%和70.7%左右。.通过以上研究，基本形成基于酮类平台化合物的生物质定向热解-集成缩合加氢制备航空燃油的理论基础。