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.
|Conference||Risø International Energy Conference 2009|
|Period||14/09/2009 → 16/09/2009|
|Series||Denmark. Forskningscenter Risoe. Risoe-R|
- Bio energy
- Biomass gasification