Waste timber pyrolysis in a medium-scale unit: Emission budgets and biochar quality
| Autor: | Ludovica Silvani, Andreas Botnen Smebye, Gerard Cornelissen, Erlend Sørmo, Helmut Dipl.-Ing. Gerber, Hans-Peter Schmidt, Gorm Thune |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Environmental Engineering
010504 meteorology & atmospheric sciences Biodegradable waste 010501 environmental sciences Contamination Combustion 01 natural sciences Pollution Aerosol Soil chemistry.chemical_compound chemistry Charcoal Environmental chemistry Biochar Environmental Chemistry Environmental science Polycyclic Aromatic Hydrocarbons Leaching (agriculture) Waste Management and Disposal Pyrolysis 0105 earth and related environmental sciences Carbon monoxide |
| Zdroj: | Science of the Total Environment |
| Popis: | Pyrolysis of organic waste or woody materials yields a stable carbonaceous product that can be mixed into soil and is often termed “biochar”. During pyrolysis carbon-containing gases are emitted, mainly volatile organic carbon species, carbon monoxide and aerosols. In modern pyrolysis units, gases are after-combusted, which reduces emissions substantially. However, emission data for medium- to large-scale pyrolysis units are scant, both regarding gases, aerosols, heavy metals and polycyclic aromatic hydrocarbons (PAH). Making biochar from lightly contaminated waste timber (WT) is a promising waste handling option as it results in the potential valorization of such residues into e.g. sorbents for contaminant stabilization. For this process to be environmentally sustainable, emissions during the process need to be low and the resulting biochar of sufficient quality. To investigate both issues, we pyrolyzed three batches of WT and one reference batch of clean wood/leaves in a representative medium-scale pyrolysis unit (Pyreg-500, 750 t/year) with after-combustion of the pyrolysis gases, and measured the gas, aerosol, metal and PAH emissions, as well as the characteristics and contamination levels of the resulting biochar, including contaminant leaching. Mean emission factors for the WT were (g/kg biochar); CO = 7 ± 2, non-methane volatile organic compounds (NMVOC) = 0.86 ± 0.14, CH4 = 0, aerosols (PM10) = 0.6 ± 0.3, total products of incomplete combustion (PIC) = 9 ± 3, PAH-16 = (2.0 ± 0.2) · 10−5, As (most abundant metal) = (2.3 ± 1.9) · 10−3 and NOX = 0.65 ± 0.10. There were no significant differences in emission factors between the pyrolysis of WT and the reference respectively, except for PM10, NMVOC, and PAH-16, which were significantly lower for WT than for the clean wood/leaves. The WT biochar did not satisfy premium or basic European Biochar Certificate criteria due to high levels of zinc and PAH. However, leachable metal contents were |
| Databáze: | OpenAIRE |
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