Co-pyrolysis of softwood with waste mussel shells: Liquid analysis

Abstract

Fast pyrolysis bio-oil (FPBO) from lignocellulosic feedstocks can be limited to applications such as heating due in part to the high oxygen and resulting acid content of the oil which complicates storage, handling, and use in traditional petroleum-based systems. Research has been carried out to enhance the oil quality, both catalytically and non-catalytically. This work focuses on utilizing by-product from the fisheries industry as a co-pyrolysis additive to enhance oil quality. Mussel shells (MS) were co-pyrolyzed with softwood forestry residues in a lab-scale, tube furnace reactor. The pyrolysis temperature (400–525 °C), nitrogen flow rate (50–300 mL/min), wood-to-MS ratio (0–50 wt% MS), and operational mode (in-situ and ex-situ) were varied in a designed experiment. The produced pyrolysis oils were analyzed for water content (Karl-Fischer titration), high heating value (HHV), total acid number (TAN), pH, density, volatility and ash content via thermogravimetric analysis (TGA), and chemical composition via gas chromatography-flame ionization detector (GC-FID) and C/H/N(O) elemental analysis. Co-pyrolysis with MS in-situ decreased the TAN of FPBO from 68 to 48mgNaOH/gOil), while the water content increased from 29 wt% to 39 wt%. However, the HHV of the water free oil increased from 22.4 to 23.6 MJ/kg indicating a reduction in oxygenated compounds, and therefore, an improvement in fuel quality of FPBO.