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Waste timber pyrolysis in a medium-scale unit: Emission budgets and biochar quality.
Sci Total Environ. 2020 May 20; 718:137335.ST

Abstract

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 <0.1% of total contents. Still, use of the WT-biochar without further improvement or investigation would be limited to ex situ use, not improving soil fertility or in situ remediation.

Authors+Show Affiliations

Norwegian Geotechnical Institute (NGI), Sognsveien 72, 0855 Oslo, Norway. Electronic address: ers@ngi.no.Norwegian Geotechnical Institute (NGI), Sognsveien 72, 0855 Oslo, Norway.Lindum AS, Lerpeveien 155, 3036 Drammen, Norway.Pyreg GmbH, Trinkbornstrasse 15-17, 56281 Dörth, Germany.Ithaka Institute for Carbon Strategies, Ancienne Eglise 9, 1974 Arbaz, Switzerland.Norwegian Geotechnical Institute (NGI), Sognsveien 72, 0855 Oslo, Norway.Norwegian Geotechnical Institute (NGI), Sognsveien 72, 0855 Oslo, Norway; Faculty of Environmental Science and Natural Resource Management (MINA), University of Life Sciences (NMBU), Universitetstunet 3, 1433 Ås, Norway. Electronic address: gco@ngi.no.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

32092519

Citation

Sørmo, Erlend, et al. "Waste Timber Pyrolysis in a Medium-scale Unit: Emission Budgets and Biochar Quality." The Science of the Total Environment, vol. 718, 2020, p. 137335.
Sørmo E, Silvani L, Thune G, et al. Waste timber pyrolysis in a medium-scale unit: Emission budgets and biochar quality. Sci Total Environ. 2020;718:137335.
Sørmo, E., Silvani, L., Thune, G., Gerber, H., Schmidt, H. P., Smebye, A. B., & Cornelissen, G. (2020). Waste timber pyrolysis in a medium-scale unit: Emission budgets and biochar quality. The Science of the Total Environment, 718, 137335. https://doi.org/10.1016/j.scitotenv.2020.137335
Sørmo E, et al. Waste Timber Pyrolysis in a Medium-scale Unit: Emission Budgets and Biochar Quality. Sci Total Environ. 2020 May 20;718:137335. PubMed PMID: 32092519.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Waste timber pyrolysis in a medium-scale unit: Emission budgets and biochar quality. AU - Sørmo,Erlend, AU - Silvani,Ludovica, AU - Thune,Gorm, AU - Gerber,Helmut, AU - Schmidt,Hans Peter, AU - Smebye,Andreas Botnen, AU - Cornelissen,Gerard, Y1 - 2020/02/14/ PY - 2019/12/09/received PY - 2020/02/11/revised PY - 2020/02/13/accepted PY - 2020/2/25/pubmed PY - 2020/6/4/medline PY - 2020/2/25/entrez KW - Biochar quality KW - Contaminated organic waste KW - Emissions KW - Leaching KW - Pyrolysis KW - Waste timber SP - 137335 EP - 137335 JF - The Science of the total environment JO - Sci. Total Environ. VL - 718 N2 - 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 <0.1% of total contents. Still, use of the WT-biochar without further improvement or investigation would be limited to ex situ use, not improving soil fertility or in situ remediation. SN - 1879-1026 UR - https://www.unboundmedicine.com/medline/citation/32092519/Waste_timber_pyrolysis_in_a_medium-scale_unit:_Emission_budgets_and_biochar_quality L2 - https://linkinghub.elsevier.com/retrieve/pii/S0048-9697(20)30845-7 DB - PRIME DP - Unbound Medicine ER -