College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China.
College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China.
Environ Res. 2023 Nov 1;236(Pt 2):116806. doi: 10.1016/j.envres.2023.116806. Epub 2023 Aug 1.
To address the issues of high oxygen content and energy consumption in the microwave-assisted pyrolysis of biomass for biofuel production, this study used high-temperature pretreated red mud (RM) as an additive. The pretreated RM exhibited dual functionalities, namely microwave absorption and catalytic properties, during the microwave-assisted pyrolysis of cow dung (CD). This study also evaluated the optimization potential of energy recovery efficiency. The results showed that the addition of pretreated RM significantly increased the oil yield during the microwave-assisted pyrolysis of CD. The highest oil yield (59.63%) was obtained via the microwave-assisted pyrolysis of CD over catalysis with RM pretreated at 750 °C (RM750). Through the optimization of the RM750-to-CD mixing ratio, optimal oil quality and energy recovery efficiency were achieved. At a mixing ratio of 1:1, the pyrolysis oil featured the highest aromatic hydrocarbon content and lowest acid content. The high-temperature pretreatment of RM increased the FeO content, which enhanced the dielectric properties and magnetic loss ability of the reactants. This resulted in localized high temperatures and the formation of "hot spots," which can promote the deoxygenation and hydrogenation reactions of oil. Consequently, the lower heating rate of oil increased from 35.12 to 40.11 MJ kg. The released oxygen escaped in the form of CO. In addition, pyrolytic char was used as an in situ microwave absorbing material owing to its increased FeO content and graphitization degree, leading to an increase in energy recovery efficiency from 4.71% to 9.98%. This study provides valuable guidance for the efficient utilization of diversified solid wastes and demonstrates the potential application of microwave-assisted pyrolysis technology in the resource utilization of solid wastes.
为了解决生物质微波热解制备生物燃料过程中氧气含量高和能耗大的问题，本研究使用高温预处理赤泥（RM）作为添加剂。预处理 RM 在牛粪（CD）的微波辅助热解过程中表现出双重功能，即微波吸收和催化性能。本研究还评估了能量回收效率的优化潜力。结果表明，添加预处理 RM 可显著提高 CD 的微波辅助热解过程中的油产率。通过 RM750 催化 CD 的微波辅助热解获得了最高的油产率（59.63%），其中 RM750 的预处理温度为 750°C。通过优化 RM750 与 CD 的混合比例，实现了最佳的油质量和能量回收效率。在混合比例为 1:1 时，热解油具有最高的芳烃含量和最低的酸含量。RM 的高温预处理增加了 FeO 含量，增强了反应物的介电性能和磁损耗能力。这导致局部高温和“热点”的形成，从而促进油的脱氧和加氢反应。因此，油的升温速率从 35.12 增加到 40.11 MJ kg。释放的氧气以 CO 的形式逸出。此外，由于 FeO 含量和石墨化程度的增加，热解炭被用作原位微波吸收材料，导致能量回收效率从 4.71%增加到 9.98%。本研究为有效利用多样化的固体废物提供了有价值的指导，并展示了微波辅助热解技术在固体废物资源利用方面的潜在应用。
