Pyrolysis oils produced from municipal solid wastes (MSW) are promising candidates for renewable sources of fuels and solvents. It has been shown that feedstock composition plays a significant role in the quality of pyrolysis oils, and municipal solid waste streams result in pyrolysis oils with greater hydrocarbon content compared to traditional biomass feedstocks that produce oxygen-rich pyrolysis oils. This outcome is not terribly surprising; and MSW components, such as plastics, have previously been mixed with biomass feedstocks to increase hydrocarbon content. However, the composition of hydrocarbons produced from pyrolysis of heavily mixed municipal wastes has not been studied in great detail. Here, we present the analysis of the saturated (sats) and aromatic (aro) hydrocarbons isolated by silica gel fractionation from two pyrolysis oils produced from unsorted landfill waste and mixed recycled plastics by comprehensive 2-dimensional gas chromatography with mass spectrometric detection (GCxGC MS) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). GCxGC analysis of the sats showed a range of paraffins and iso-paraffins for both pyrolysis oils; however, the landfill pyrolysis oil also contained olefins. FT-ICR MS confirmed the GCxGC results and showed the double bond equivalents ranged from 0~4 for plastic and 0~7 for landfill. Analysis of the aro showed a wide range of aromatic components, with the landfill pyrolysis oil containing a greater concentration of condensed ring structures compared to the more alkylated ring structures seen in the plastic pyrolysis oil. This finding was confirmed with structural assignments made by GCxGC. Insight into the structure and composition of hydrocarbon compounds provides useful information regarding the potential uses of MSW-derived bio-oils and may provide key information to better understand decomposition and condensation reactions that occur during pyrolysis.

Analysis of hydrocarbons from municipal waste pyrolysis oils by gas chromatography and Fourier transform ion cyclotron resonance mass spectrometry

254th National Meeting (2017)

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