Catalytic pyrolysis of forest thinnings with ZSM-5 catalysts: Effect of reaction temperature on bio-oil physical properties and chemical composition

Ville Paasikallio, Foster Agblevor, Anja Oasmaa, Jani Lehto, Juha Lehtonen

Research output: Contribution to journalArticleScientificpeer-review

15 Citations (Scopus)

Abstract

In this study, noncatalytic and catalytic fast pyrolysis of forest thinnings was carried out in a bench-scale bubbling fluidized bed reactor using two commercial ZSM-5 catalysts. After the initial comparison experiments at 475 C, the catalyst which showed a clearly higher activity was further tested at reaction temperatures of 400 and 550 C. The yield of organic liquids, which was 39 wt % in the noncatalytic experiment, decreased to 14-24 wt % depending on the reaction temperature. Varying the reaction temperature while using the ZSM-5 catalyst also caused significant changes in the elemental composition, viscosity, and pH, as well as the chemical composition of bio-oil. In general, the use of the catalyst resulted in a less viscous bio-oil with an oxygen content as low as 19 wt %. The catalytically produced bio-oil contained less carbohydrate degradation products and more aromatic compounds. Based on the chemical characterization results (13C nuclear magnetic resonance spectroscopy, gas chromatography-flame ionization detector, gas chromatography-mass spectrometry, and solvent fractionation) obtained in this study, a new supplementary procedure for the existing solvent fractionation method was suggested to be used as an initial screening tool for aromatic hydrocarbon content in bio-oil samples. In this procedure, a water-insoluble, dichloromethane-soluble fraction containing low molecular mass lignin compounds and aromatic hydrocarbons is first isolated using solvent fractionation. When the dichloromethane is allowed to evaporate at room temperature, the consequent mass loss of the pyrolysis products exhibits a linear correlation with the content of aromatic hydrocarbons in bio-oil, as quantified by gas chromatographic methods.

Original languageEnglish
Pages (from-to)7587-7601
JournalEnergy & Fuels
Volume27
Issue number12
DOIs
Publication statusPublished - 19 Dec 2013
MoE publication typeA1 Journal article-refereed

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