Ambus, Per

Bruun, Esben

Egsgaard, Helge

Hauggaard-Nielsen, Henrik

Jensen, Peter Arendt

Production of energy carriers (oil, gas) and biochar from pyrolysis of biomass is by many considered a promising technology for combined production of bioenergy and recalcitrant C suitable for sequestration in soil. The mechanism behind biochar-C sequestration is straightforward: Due to its recalcitrant characteristics the microbial decomposition of biochar is much slower in comparison to the mineralization of the original feedstock. Conversion of organic residues like household waste or cereal straw to biochar is hence proposed a way to withdraw CO2 from the atmosphere and sequester it on a long term basis in the soil. The experiments presented here illustrate the C sequestration potentials of biochar originating from fast pyrolysis of wheat straw. It is documented that after 47 days in soil 95 % of the added biochar-C is still present in the soil as compared to only 56 % if straw is applied untreated to the soil. The type and settings of pyrolysis influence the chemical quality of the biochar produced significantly. Biochar chemical analysis revealed that the degradation of biochar in soil appears to be proportional with the biochar cellulosic and hemicellulosic fraction. Furthermore, the pyrolyzer temperature settings strongly influence the proportion of cellulose and hemicellulose remaining in the biochar. As these biochar fractions relatively rapidly are mineralized to CO2 by microbial respiration they are – in climate mitigation perspective - unwanted. At the upcoming Climate Conference in Copenhagen (COP15) December 2009, the use of biochar as a mitigation tool will be on the agenda and for the time being (July 2009) 20 countries and Parties to the United Nations Framework Convention on Climate Change (UNFCCC) have made submissions to the UNFCCC seeking the inclusion of biochar as a climate mitigation and adaptation tool

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Downloaded from orbit.dtu.dk on: Dec 18, 2017Biochar soil application to mitigate climate changeBruun, Esben; Hauggaard-Nielsen, Henrik; Ambus, Per; Egsgaard, Helge; Jensen, Peter ArendtPublished in:Energy solutions for CO2 emission peak and subsequent declinePublication date:2009Link back to DTU OrbitCitation (APA):Bruun, E., Hauggaard-Nielsen, H., Ambus, P., Egsgaard, H., & Jensen, P. A. (2009). Biochar soil application tomitigate climate change. In Energy solutions for CO2 emission peak and subsequent decline: Proceedings (pp.86-96). Roskilde: Danmarks Tekniske Universitet, Risø Nationallaboratoriet for Bæredygtig Energi.  (Denmark.Forskningscenter Risoe. Risoe-R; No. 1712(EN)).Biochar soil application to mitigate global changeEsben Bruun, PhD candidate RISØ DTU1Bruun  E W  (esbr@risoe dtu dk); 1Hauggaard-Nielsen  H ; , . . . . , .1Ambus P.; 1Egsgaard, H.; 2Jensen P. A. 1Biosystems Division, Risø National Laboratory for Sustainable fEnergy, Technical University o  Denmark, DK-4000 Roskilde, Denmark; 2Division of Chemical Engineering Competences. Technical University of Denmark, DK-2800 Lyngby, DenmarkIntroduction to biocharWhat is biochar? • Biochar is just another word for charcoalHow is biochar made?• Biochar is produced through the heating of biomass under air-deprived conditions. A process called pyrolysis. I  th  l i   bi il d   What are the benefits of biochar?• n e pyro ys s process o-o an gas areproduced as well• Biochar can be used for carbon (C) sequestration (storage) and GHG inhibition in soil. Bio-oil can f fsubsidize ossil uels• Biochar enhances soil fertilityand crop yieldsRisø DTU, Technical University of Denmark2Soils are very important sinks for carbon!• The application of biochar to agricultural lands is one way to increase soil CSource: Mike FowkesRisø DTU, Technical University of Denmark3The mechanism behind C sequestrationFrom Lehmann 2007, Nature.Risø DTU, Technical University of Denmark4The stability of biochar in soil• The stability of biochar is of fundamental importance as it determines how long biochar-C applied to soil will remain sequestered • Biochar typically has the greatest average age of any C fraction• Biochar from wildfires is frequently found to be more than 10 000 years ,oldRisø DTU, Technical University of Denmark5Is biochar to be taken seriously?G i  i tifi  d bli   N t 2  S i 3  ll  • row ng sc en c an pu c awareness: a ure , c ence as we asBBC, Times and CNN have all published papers/information about biochar • Dr. Johannes Lehmann has given testimony about biochar before the House of representatives (US) Select Committee on Energy Independence and Global Warming• Companies already with pyrolysis production facilities are rising in numbers (e.g. Best Energies, Eprida, Dynamotive)1) http://news.bbc.co.uk/2/hi/science/nature/7924373.stm ; 2) Lehmann J. (2007) 3) Wardle et al (2008). 4) Gaunt d hRisø DTU, Technical University of Denmarkan  Le mann 20086My research• Incubation studies with focus on short term degradation of different types of biochars in a temperate loam soilRisø DTU, Technical University of Denmark7Mineralization of fast and slow pyrolysis biochar compared to strawSlow pyrolysisfast pyrolysis+2g fast pyrolysis biochar+2g straw (feedstock for biochar)+2g slow pyrolysis biochar40g soil REFMineralization of biochars made at different  pyrolysis temperatures40g soil REF+2g fast pyrolysis biochar500°C 525°C 550°C 575°CRisø DTU, Technical University of Denmark8feedstock straw475°CMineralization of fast and slow pyrolysis biochar compared to strawRisø DTU, Technical University of Denmark9Cumulated C-lossRisø DTU, Technical University of Denmark10Mineralization of biochars made at different  pyrolysis temperaturesRisø DTU, Technical University of Denmark11Cumulated biochar C loss (%)Risø DTU, Technical University of Denmark12Biochar cellulosic and hemicellulosic C fractions3540ose-C2530micelluloR² = 0 986101520e-C + hem(%)  ,05Cellulose450 475 500 525 550 575 600CPyrolysis temp. (C )°Risø DTU, Technical University of Denmark13Cellulosic and hemicellulosic fraction correlated with biochar-C decayC)of initial Coss (% oC lRisø DTU, Technical University of Denmark14Conclusions• biochar soil application can be used to store carbon in soil• biochar carbon loss is correlated with the specific pyrolysis technology and production temperature• short-term degradation of fast pyrolysis biochar is proportional to the content of cellulosic and hemicellulosic carbon in the biochar• A holistic approach is recommended when managing the pyrolysis process, so both the produced bio-oil (and hence avoided use of fossil fuel) and biochar C-sequestration is optimized to give the overall largest net avoidance of CO2 emissions  Risø DTU, Technical University of Denmark15Thank you for your attention• More information about biochar on: www.biochar-international.org/ • Special thank to Henrik Hauggaard-Nielsen, Per Ambus, Helge Egsgaard and Hanne Wojtaszewski and Tobias ThomsenRisø DTU, Technical University of Denmark16AppendixBiochar has been used before:Dark soils of AmazonasRisø DTU, Technical University of Denmark17AppendixBiochar has been used before:Dark soils of AmazonasRisø DTU, Technical University of Denmark18Biochar increases crop yieldsRisø DTU, Technical University of DenmarkRisø DTU, Technical University of Denmarkwww.biochar.info/Physical properties• Particle sizes in the range of 1µm to 1mm• The porosity is large! 1g biochar typically has a surface area of 300-400m2FigureSEM-images of caseinRisø DTU, Technical University of Denmark  biocharCellulosic and hemicellulosic fraction Biochar Biochar Biochar Biochar BiocharTable 1. Average particle sizes of the added biochars.correlated with biochar-C decay475°C 500°C 525°C 550°C 575°CAverage size (µm ±SE) 70.9±6 49.7±4.5 17.1±1.4 12±0.9 11.5±0.8Min-max size 18.8-489.7 10.7-223.3 2.9-100.5 2.2-55.8 2.1-59.7Risø DTU, Technical University of Denmark22Optimal pyrolysis temperatureOverall mass balances for feedstock strawRisø DTU, Technical University of Denmark23From Ibrahim et al., unpublished data) Critical reflections• Are there any health risk with biochar? • how do we amend biochar with the soil? • How do we avoid deforestation of primary forest (jungle) for biochar and biooil production?Risø DTU, Technical University of Denmark24

Biochar soil application to mitigate climate change

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Biochar soil application to mitigate climate change

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