Identifying the primary reactions and products of fast pyrolysis of alkali lignin
•Fast pyrolysis of alkali lignin promoted primary reactions.•The yield of pyrolysis of products increased with temperature and residence time.•Competitive reactions took place to form the products.•The main products were guaiacyl type compounds and acetaldehyde. This study focused on the effect of t...
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Veröffentlicht in: | Journal of Analytical and Applied Pyrolysis 2020-10, Vol.151, p.104917, Article 104917 |
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Sprache: | eng |
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Zusammenfassung: | •Fast pyrolysis of alkali lignin promoted primary reactions.•The yield of pyrolysis of products increased with temperature and residence time.•Competitive reactions took place to form the products.•The main products were guaiacyl type compounds and acetaldehyde.
This study focused on the effect of temperature and residence time on the primary thermal decomposition reactions during a fast pyrolysis of softwood alkali lignin. The use of Py-GC/MS/FID (Micropyrolyser-Gas Chromatography/Mass Spectrometry/Flame Ionization Detector) allowed for rapid heating of the sample and detailed identification and quantification of the pyrolysis products at a temperature range of 400–600 °C, with residence times from 0.5–5 s. The identified primary pyrolysis products were mainly volatile guaiacyl-type compounds. There was a general increase in yield for the majority of the volatile compounds with increased temperature and time. The cleavage of the lignin polymer to linear carbonyl (acetaldehyde) and guaiacyl-type aromatic compounds increased with temperature, while that of catechol and cresol type was mainly favoured at 500 and 600 °C. Based on these results, a mechanistic pathway for the pyrolytic process was proposed, drawing a linkage from structural units of lignin to the formed primary products. In summary, our findings suggest that the primary decomposition reactions that occur under the fast pyrolysis conditions can be controlled by varying the process temperature and residence time, and deliver mechanistic insight into the product distribution from structurally complex lignin material. |
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ISSN: | 0165-2370 1873-250X 1873-250X |
DOI: | 10.1016/j.jaap.2020.104917 |