- Pyrolysis oil
Pyrolysis oil is under investigation as substitute for
petroleum . It is extracted bydestructive distillation from driedbiomass in a reactor at temperature of about 500°C with subsequent cooling. Pyrolytic oil is a kind oftar and normally contains too high levels of oxygen to be ahydrocarbon . As such it is distinctly different from similar petroleum products.Process
The biomass is split into solid, liquid, and gaseous components under the influence of heat only (
anhydrous pyrolysis ). The producedcharcoal may be used for heating the process, used as a soil additive asbiochar , or asactivated carbon in absorption processes. The gas, consisting ofhydrogen (H2),carbon monoxide (CO),carbon dioxide (CO2) andmethane (CH4), may be burned but the condensible gases have to be kept gaseous until thecombustion . The heating value is 15-22 MJ/m3, which is much lower thannatural gas .Fuel oil characteristics
The produced oil is sour with a
pH of 1.5-3.8 (2.8) and has an elevated water content 8-20% wt. This leads tocorrosion problems especially at higher temperatures. The density is approximately 1.2-1.3 (1.22) kg/l or 10.01-10.85 (10.18) lbs/gallon, which is much higher compared todiesel . The oxygen content is 40-50%, mostly from the water content, and nosulfur may be detected normally. The lower heating value is approximately 16-21 (17.5) MJ/kg. The pour point is -12°C to -33°C, nocloud point could be observed until -21°C. The carbon residue is 17-23 % wt (0.13%ash ). The flash point is 40-100°C, the pyrolysis oil is not auto-igniting in adiesel engine . Thecetane number is only minus 10. Theviscosity increases to a maximum in period of 12 months due topolymerization . The pyrolysis oil is not stable reacting with air and degasing. Pyrolysis oil cannot be blended with diesel [ [http://www.de.unifi.it/Macchine/Martelli/CORSI-MARTELLI/ENERGIE-RINNOVABILI/Dispense/ER_Pyro%201.0.pdf] Dead link|date=March 2008] .It may be very attractive, from an economic standpoint, to first recover valuable bio-chemicals from the bio-oil. The remainder of the bio-oil can then be combusted to generate electricity or converted to a
syngas from which chemicals and clean fuels can be synthesized [http://www.geagroup.com/imperia/md/content/presse/2005.11.30_presentation_dr_plass_e.pdf] .ee also
*
Biodiesel References
External links
* [http://www.agri-therm.com/index.html Agri-Therm technology for conversion of agricultural waste to bio-oil]
* [http://www.btgworld.com/2005/pdf/technologies/leaflet-fast-pyrolysis.pdf download leaflet]
* [http://www.combio-project.com/download/PDF/Presentation_Chile_Nov2004.pdf download COMBIO project]
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