Ex situ catalytic fast pyrolysis (ex-CFP) of biomass applying ZSM-5 catalysts is an effective method for deoxygenating the pyrolysis vapour, thus producing low-oxygen bio-oil in a single step. The catalysts deactivate after reactions but can be regenerated to recover their performance. Most of the previous studies on catalyst regeneration applied modified ZSM-5 catalysts to produce partially deoxygenated bio-oil with an oxygen content of around 10–25 wt%. In the deep deoxygenation region with bio-oil oxygen content below 5 wt%, the regeneration of pristine HZSM-5 catalyst used in ex-CFP where filtered pyrolysis vapour is upgraded has not been elucidated. Therefore, it is the main purpose of the current study to demonstrate the deep-deoxygenation capability of an unmodified HZSM-5 catalyst that has been previously depreciated. In this work, eucalyptus wood was pyrolysed in a bench-scale bubbling fluidised-bed reactor close-coupled with a separate catalytic reactor containing a fixed bed of pristine HZSM-5 extrudates. The produced catalytic bio-oil appears in 3 phases: light bio-oil, medium aqueous phase and heavy bio-oil. The light bio-oil has a very low oxygen content of ∼1 wt%, containing mainly monocyclic aromatic hydrocarbons, especially benzene, toluene and xylene. The heavy liquid had an oxygen content of 5–8 wt%, containing mainly naphthalene derivatives. The average degree of deoxygenation achieved in this work was 91% throughout the 10 experiments using fresh and regenerated catalysts. The unmodified HZSM-5 extrudates can be considered regenerable for up to 9 cycles with minor catalyst deactivation. The yields of main products including total bio-oil, char and gas were unaffected by the catalyst regeneration. However, the yield of light bio-oil appeared to gradually decrease with regeneration cycles. The regenerated catalyst could retain its surface area, morphology and structural framework to a great extent, albeit with small changes occurring on the surface area and volume of the micropores as well as its crystallinity and crystalline size.

中文翻译：

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在台式流化床反应器中通过生物质的异位催化快速热解生产深度脱氧生物油期间原始 HZSM-5 挤出物的再生

异地应用 ZSM-5 催化剂对生物质进行催化快速热解 (ex-CFP) 是一种有效的方法，可对热解蒸汽进行脱氧，从而一步生产低氧生物油。催化剂在反应后失活，但可以再生以恢复其性能。之前关于催化剂再生的大多数研究都应用改性 ZSM-5 催化剂来生产氧含量约为 10-25 wt% 的部分脱氧生物油。在生物油含氧量低于 5 wt% 的深度脱氧区，用于过滤热解蒸汽升级的 ex-CFP 中使用的原始 HZSM-5 催化剂的再生尚未阐明。因此，本研究的主要目的是证明先前已折旧的未改性 HZSM-5 催化剂的深度脱氧能力。在这项工作中，桉木在实验室规模的鼓泡流化床反应器中热解，该反应器与单独的催化反应器紧密耦合，该反应器包含原始 HZSM-5 挤出物的固定床。产生的催化生物油分三相：轻生物油、中水相和重生物油。轻质生物油的含氧量非常低，约为 1 wt%，主要包含单环芳烃，尤其是苯、甲苯和二甲苯。重质液体的氧含量为 5-8 wt%，主要含有萘衍生物。在使用新鲜和再生催化剂的 10 次实验中，这项工作中实现的平均脱氧程度为 91%。未改性的 HZSM-5 挤出物可被视为可再生多达 9 个循环，且催化剂轻微失活。包括总生物油在内的主要产品的产量，炭和气体不受催化剂再生的影响。然而，随着再生循环，轻质生物油的产量似乎逐渐下降。再生后的催化剂可以在很大程度上保持其表面积、形态和结构骨架，尽管微孔的表面积和体积以及结晶度和结晶尺寸发生了很小的变化。