Abstract The present work focuses on the sampling procedure and quantification of the PAH yield from the fast pyrolysis of waste softwood. In particular, fast pyrolysis experiments were conducted using a CDS Pyroprobe 5200 at temperatures between 500 °C and 1000 °C, at a heating rate of 600 °C/s for a sample size of 30 mg. High performance liquid chromatography (HPLC) was used for the determination of the PAH compounds present in the liquid sample fraction, while a micro – GC was employed for the analysis of the main gaseous products (CO, CO2, CH4 and H2). An alternative tar sampling protocol was proposed, which employed the use of a cold trap (50 °C) and an isopropanol filled impinger bottle for the collection of the condensable products. The experiments were compared to heated foil reactor based pyrolysis tests within the same temperature range and heating rate, except for a slightly lower sample size (10 mg). The Pyroprobe and adapted sampling system proved to be more efficient regarding PAH capture and quantification compared to the heated foil reactor. Naphthalene, acenaphthylene and phenanthrene were the main PAH compounds detected. The PAH yields increased with pyrolysis temperature, up to values corresponding to roughly 0.2 wt% of the overall yield at 1000 °C. From the results it was derived that PAH evolution is mainly a product of secondary decomposition of primary tar, since the char yield stabilized for higher temperatures and the yields of CO, H2 and CH4 increased. Overall mass balance closure values were around 80 wt% on average. Char and gas yields were determined with high reproducibility, however gravimetric liquid analysis lacked due to the inability to gravimetrically measure the yield condensing in the impinger bottle. Future work is aimed on improving on this particular aspect. Overall, the alternative tar sampling system proposed was successful in the quantification of PAH from biomass fast pyrolysis experiments offering increased flexibility, accuracy and practicality of use.

中文翻译：

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木本生物质快速热解中多环芳烃的采样和量化在带有改进焦油采样系统的热探针反应器中

摘要 目前的工作重点是废针叶木快速热解过程中 PAH 产量的采样程序和量化。特别是，使用 CDS Pyroprobe 5200 在 500 °C 和 1000 °C 之间的温度下进行快速热解实验，加热速率为 600 °C/s，样品大小为 30 mg。高效液相色谱 (HPLC) 用于测定液体样品部分中存在的 PAH 化合物，而微型 GC 用于分析主要气态产物（CO、CO2、CH4 和 H2）。提出了另一种焦油采样协议，该协议采用冷阱 (50 °C) 和填充异丙醇的撞击瓶来收集可冷凝产品。在相同的温度范围和加热速率下，将实验与基于加热箔反应器的热解测试进行比较，只是样品尺寸略小（10 毫克）。事实证明，与加热的箔式反应器相比，Pyroprobe 和适配的采样系统在 PAH 捕获和量化方面更有效。萘、苊和菲是检测到的主要多环芳烃化合物。PAH 的产率随着热解温度的增加而增加，在 1000 °C 时达到相当于总产率的大约 0.2 wt% 的值。结果表明，PAH 的析出主要是初级焦油二次分解的产物，因为炭产量在较高温度下稳定，并且 CO、H2 和 CH4 的产量增加。总体质量平衡闭合值平均约为 80 重量％。炭和气体产量的测定具有很高的重现性，但是由于无法通过重量法测量冲击瓶中冷凝的产量，因此缺乏重量法液体分析。未来的工作旨在改进这一特定方面。总体而言，所提出的替代焦油采样系统成功地从生物质快速热解实验中定量 PAH，从而提高了使用的灵活性、准确性和实用性。