Complementary analysis of the water-soluble and water-insoluble fraction of catalytic fast pyrolysis biocrudes by two-dimensional gas chromatography

Abstract

Catalytic fast pyrolysis (CFP) biocrudes are of interest in the search for renewable energy and fuel. Depending on the process conditions, the produced biocrude can contain low to high percentage of oxygenates such as polyphenols, aldehydes/ketones, furan derivatives, acids, and sugars. The presence of these oxygenates leads to difficulties in handling, storage, and downstream processing. A better understanding of the chemical composition of biocrudes produced under different conditions, and their reactivity in the hydrotreatment process, is required to optimize the CFP process. In this study, we perform a comprehensive characterization of five biocrude samples from loblolly pine (pinus taeda), produced under different CFP conditions, by fractionation, automatic precolumn derivatization, and comprehensive two-dimensional gas chromatography (GC X GC). The findings show that sample fractionation simplifies the chromatograms by separating the biocrudes into fractions based on polarity. Additionally, fractionation and derivatization enable the analysis of polar oxygenates (e.g., acids and sugars) that are present in low relative amounts in the biocrudes. In general, the use of complementary GC X GC methods resulted in separation and detection of compounds in a wide polarity range and enabled the detection of polar oxygenates in the biocrude samples.