双功能炭基催化剂催化木塑定向热解制取富烃燃油的机理研究

Wood plastic composite (WPC) with interesting mechanical and physical properties together with their sustainable character has been widely used in building & construction products, automotive components, interior decoration, and others in recent years. However, serious deteriorations resulting from its macromolecular degradation make WPC unsuitable to use as a material after times of recycling and reuse. WPC becomes a new solid waste which needs to be disposed harmlessly. This project proposed to prepare bifunctional carbon base catalyst with acidulated activated carbon as carrier and metal as active component, and realize the efficient transformation of WPC waste via catalytic fast pyrolysis. The effects of pore structure, acidic properties and metal loading factors on the catalyst reactivity are studied, and the structure-activity relationship of catalyst in WPC waste directional pyrolysis is established. Variable work condition tests and studies on the evolution of functional groups are conducted to reveal the directional conversion mechanism of several components of WPC waste pyrolysis vapors. Pyrolytic products difference analysis, the evolution of functional groups and carbon sharing mechanism are investigated to illuminate the synergistic effects between biomass and plastic in WPC waste, and the mechanism of hydrocarbons formation promoted by this synergistic effects is revealed. This research results will provide theoretical support for the efficient conversion of WPC waste into hydrocarbon-rich bio-oil.

近年来，木塑复合材料（WPC）凭借优异的物理、力学性能和环境友好性等特点在建筑用材、汽车零部件和室内装饰等领域得到广泛应用。然而，经多次循环利用后的WPC由于大分子降解导致力学性能降低而不适于继续用作材料，作为一种新型的固体废弃物必须对其进行无害化处理。本项目提出构建以酸化活性炭为载体、以金属为活性组分的双功能炭基催化剂，通过催化快速热解实现WPC废弃物的高效转化。首先研究催化剂的孔道结构、表面酸性及金属负载等因素对其反应活性的影响规律，明确WPC定向热解中催化剂构效关系，结合工况实验和官能团演变规律研究，深入解析WPC热解气多组分定向催化转化为轻质烃类的反应机理。通过产物差异性分析、官能团演变规律和碳元素共用机制研究，阐明WPC中生物质与塑料之间的协同作用机制，揭示该协同效应促进烃类生成的机理。项目研究将为WPC废弃物高效转化为富烃燃油提供理论支持。

木塑复合材料（主要由生物质与塑料组成）凭借优异的物理力学性能和环境友好性等特点得到了广泛的应用。针对木塑废弃物资源化处理这一问题，本项目提出构建双功能型炭基催化剂，通过快速热解实现木塑废弃物高效转化为富烃燃油的思路。项目取得的主要研究成果如下：（1）催化剂构效关系方面：研究了制备参数与改性方法等对炭基催化剂的比表面积、孔容、酸强度、表面形貌和官能团等性质的影响规律，炭化温度和活化剂浓度对催化剂的孔道结构有重要影响，磷酸活化炭基催化剂成功引入了-P=O、-C-O-P、-PO等含磷弱酸性官能团，Fe和B掺杂进一步增加了炭基催化剂的活性位点，改善了其催化性能；（2）木塑催化热解方面：研究了热解温度、不同炭基催化剂及用量等因素对生物质与塑料共热解产物产率与分布变化的影响规律，解析了共热解中间体在炭基催化剂作用下的反应路径与机理，当热解温度为500℃，10Fe/PAC催化剂与原料质量比为2:1时，目标产物芳烃的含量高达77.14%；（3）催化剂催化寿命方面：探索了炭基催化剂的抗积碳失活性能与催化寿命，对使用前后炭基催化剂的孔结构和表面性质等进行表征分析，发现炭基催化剂循环利用三次后基本失去催化活性，而Fe负载炭基催化剂可有效延长其催化寿命；（4）生物质与塑料催化协同作用方面：系统研究了生物质及其主要组分（纤维素、半纤维素、木质素）与塑料共热解中间产物在炭基催化剂活性位点上的相互作用机制，二者的相互作用促进了芳烃和氢气的生成，芳烃含量增加了136%~173.79%，气体含量增加了30.29%~85.41%。以上研究为木塑废弃物资源化转化为富烃燃料奠定了理论基础。