title: PCDDs, PCDFs and PCNs in products of microwave-assisted pyrolysis of woody biomass--Distribution among solid, liquid and gaseous phases and effects of material composition.
abstract: Microwave-assisted pyrolysis (MAP) of lignocellulosic biomass is a technique that could potentially be used to produce and upgrade renewable energy carriers. However, there is no available information about the formation of dioxins and other organic pollutants in MAP treatment of woody biomass. In this study, MAP experiments were conducted in lab-scale using virgin softwood, bark, and impregnated wood as feedstocks. The non-condensable gas, liquid (fractionated into aqueous and oil phases), and char fractions generated during pyrolysis were collected and analysed for polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and naphthalenes (PCNs). The concentrations of PCDDs, PCDFs and PCNs in the pyrolysis products ranged from 0.52 to 43.7 ng kg(-1). All investigated compound groups were most abundant in the oil fraction, accounting for up to 68% (w/w) of the total concentrations. The highest PCDD, PCDF and PCN concentrations were found from the pyrolysis of bark, which has relatively high contents of chlorine and mineral matter, followed by impregnated wood, which contains organic and metal-based preservatives. The homologue profiles of all three compound groups were dominated by the less chlorinated homologues. The homologue abundance decreased as the degree of chlorination increased. This trend was observed for all three feedstocks.
authors.affiliation: Umeå University, Department of Chemistry, SE -901 87, Sweden.
authors.forename: Qiuju
authors.initials: Q
authors.lastname: Gao
authors.affiliation: University of York, Green Chemistry Centre of Excellence, Department of Chemistry, YO10 5DD, UK.
authors.forename: Vitaliy L
authors.initials: VL
authors.lastname: Budarin
authors.affiliation: Energy Research Centre of the Netherlands, ECN Biomass and Energy Efficiency, 1755 ZG, Petten, The Netherlands.
authors.forename: Mariusz
authors.initials: M
authors.lastname: Cieplik
authors.affiliation: York Science Park, Biorenewables Development Centre, York, YO10 5NY, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Gronnow
authors.affiliation: Umeå University, Department of Chemistry, SE -901 87, Sweden. Electronic address: stina.jansson@umu.se.
authors.forename: Stina
authors.initials: S
authors.lastname: Jansson
mesh_terms: D001572:Benzofurans / Q000032:analysis*; D018533:Biomass; D000072338:Dibenzofurans, Polychlorinated; D005740:Gases / Q000032:analysis; D008872:Microwaves; D009281:Naphthalenes / Q000032:analysis*; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis; D014934:Wood / Q000737:chemistry*
chemical_list: D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D005740:Gases; D009281:Naphthalenes; D000072317:Polychlorinated Dibenzodioxins
keywords: Lignocellulosic biomass; Persistent organic pollutants; Polychlorinated dibenzo-p-dioxins; Polychlorinated dibenzofurans; Polychlorinated naphthalenes; Thermochemical conversion