Ohra-Aho Taina, Rohrbach Léon, Winkelman Jozef G M, Heeres Hero J, Mikkelson Atte, Oasmaa Anja, van de Beld Bert, Leijenhorst Evert J, Heeres Hans
VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 Espoo, Finland.
Department of Chemical Engineering (ENTEG), University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Energy Fuels. 2021 Nov 18;35(22):18583-18591. doi: 10.1021/acs.energyfuels.1c02208. Epub 2021 Oct 29.
Fast pyrolysis bio-oil (FPBO), a second-generation liquid bioenergy carrier, is currently entering the market. FPBO is produced from biomass through the fast pyrolysis process and contains a large number of constituents, of which a significant part is still unknown. Various analytical methods have been systematically developed and validated for FPBO in the past; however, reliable methods for characterization of acetaldehyde, formaldehyde, and furfural are still lacking. In this work, different analysis methods with (HS-GC/ECD, HPLC, UV/Vis) and without derivatization (GC/MSD, HPLC) for the characterization of these components were evaluated. Five FPBO samples were used, covering a range of biomass materials (pine wood, miscanthus, and bark), storage conditions (freezer and room temperature), and after treatments (none, filtration, and vacuum evaporation). There was no difference among the methods for the acetaldehyde analysis. A significant difference among the methods for the determination of formaldehyde and furfural was observed. Thus, more data on the accuracy of the methods are required. The precision of all methods was below 10% with the exception of the HPLC analysis of acetaldehyde with an RSD of 14%. The concentration of acetaldehyde in the FPBO produced from the three different biomasses and stored in a freezer after production ranged from 0.24 to 0.60 wt %. Storage at room temperature and vacuum evaporation both decreased significantly the acetaldehyde concentration. Furfural concentrations ranged from 0.11 to 0.36 wt % for the five samples. Storage and after treatment affected the furfural concentration but to a lesser extent than for acetaldehyde. Storage at room temperature decreased formaldehyde similarly to acetaldehyde; however, after vacuum-evaporation the concentration of formaldehyde did not change. Thus, the analysis results indicated that in FPBO the equilibrium of formaldehyde and methylene glycol is almost completely on the methylene glycol side, as in aqueous solutions. All three methods employed here actually measure the sum of free formaldehyde and methylene glycol (FAMG).
快速热解生物油（FPBO）作为第二代液体生物能源载体，目前正在进入市场。FPBO是通过快速热解过程由生物质生产的，含有大量成分，其中很大一部分仍然未知。过去已经系统地开发并验证了各种用于FPBO的分析方法；然而，仍然缺乏用于表征乙醛、甲醛和糠醛的可靠方法。在这项工作中，评估了用于表征这些成分的不同分析方法，包括有衍生化（HS-GC/ECD、HPLC、UV/Vis）和无衍生化（GC/MSD、HPLC）的方法。使用了五个FPBO样品，涵盖了一系列生物质材料（松木、芒草和树皮）、储存条件（冷冻和室温）以及后处理（无、过滤和真空蒸发）。在乙醛分析方法之间没有差异。在甲醛和糠醛的测定方法之间观察到显著差异。因此，需要更多关于这些方法准确性的数据。除了乙醛的HPLC分析RSD为14%外，所有方法的精密度均低于10%。由三种不同生物质生产并在生产后储存在冷冻室中的FPBO中乙醛浓度范围为0.24至0.60 wt%。室温储存和真空蒸发均显著降低了乙醛浓度。五个样品的糠醛浓度范围为0.11至0.36 wt%。储存和后处理影响糠醛浓度，但程度小于乙醛。室温储存对甲醛的影响与乙醛类似；然而，真空蒸发后甲醛浓度没有变化。因此，分析结果表明，在FPBO中，甲醛和亚甲基二醇的平衡几乎完全在亚甲基二醇一侧，与水溶液中一样。这里使用的所有三种方法实际上测量的是游离甲醛和亚甲基二醇（FAMG）的总和。
