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United States Department of Agriculture

Agricultural Research Service

Research Project: DISTRIBUTED-SCALE PYROLYSIS OF AGRICULTURAL BIOMASS FOR PRODUCTION OF REFINABLE CRUDE BIO-OIL AND VALUABLE COPRODUCTS

Location: Sustainable Biofuels and Co-Products

Title: Evaluation of Brazilian biomasses as potential feedstocks for fuel production via fast pyrolysis

Authors
item Pighinelli, Anna -
item Boateng, Akwasi
item Mullen, Charles
item Elkasabi, Yaseen

Submitted to: Energy for Sustainable Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 18, 2014
Publication Date: June 10, 2014
Citation: Pighinelli, A.L., Boateng, A.A., Mullen, C.A., Elkasabi, Y.M. 2014. Evaluation of Brazilian biomasses as potential feedstocks for fuel production via fast pyrolysis. Energy for Sustainable Development,21:p.42-50.

Interpretive Summary: Brazil has a large availability of wood and agricultural residues that can be exploited as potential pyrolysis feedstocks. Pyrolysis, the thermal decomposition of biomass in the absence of oxygen, can produce bio-oil, biochar or gaseous fuels. In this research, residue from sugarcane harvesting (named trash) and eucalyptus Benthamii were evaluated as potential feedstocks for bio-oil and biochar production by fast pyrolysis. For that, we tested two different sets of process conditions. In the first, an inert gas (nitrogen) was used as a fluidizing agent while in the second, a USDA process which employs a mixture of nitrogen and recycled pyrolysis effluent gas was used. By comparing both processes, it was evident that partial use of the effluent gas dramatically improved the quality and stability of the liquid fuels by reducing water, oxygen, acidity, viscosity and increasing the heating value of the liquid product. However, there was a yield penalty in bio-oil production when a reactive atmosphere was used. Pyrolysis of the trash under the recycled atmosphere produced more gases than bio-oil. With regards to eucalyptus biochars obtained under both atmospheres, their similarity with bituminous coal favors the application of these residues as a solid fuel, while for the sugarcane trash the higher ash content in the biochars could make their utilization as soil amendment more favorable.

Technical Abstract: The utilization of lignocellulosic materials to generate energy is constantly expanding around the world. In addition to the well-known biofuels such as ethanol and biodiesel, advanced biofuels obtained by thermochemical conversion routes have been explored, including pyrolysis oil, biochar and syngas. Brazil has a large availability of biomass such as wood and agricultural residues that can be exploited as potential pyrolysis feedstocks. The objective of this work was to evaluate sugarcane trash (Saccharum) and eucalyptus Benthamii (E.benthamii) as potential feedstocks for liquid and solid fuels production by fast pyrolysis. This particular species of eucalyptus was chosen among others available in Brazil including E. urograndis, E. grandis and E. urophylla. Fast pyrolysis of the E.benthamii and sugarcane trash was conducted in a fluidized bed reactor using two different sets of process conditions. In the first, an inert gas (nitrogen) was used as a fluidizing agent while in the second, a USDA process which employs a reactive atmosphere by a mixture of nitrogen and recycled pyrolysis effluent gas was used. By comparing both processes, it was evident that partial use of the effluent gas dramatically improved the quality and stability of the liquid fuels by reducing water, oxygen, TAN, viscosity and increasing the higher heating value (HHV) of the liquid product. Concentrations of highly oxygenated compounds such as acetic acid, acetol and levoglucosan in the liquid product decreased under the reactive atmosphere. Simultaneously, some aromatic hydrocarbons not initially observed in the traditional bio-oil were found. However, there was a yield penalty of about 13.5 wt% (db) in bio-oil production when a reactive atmosphere was used. The recycled process made it possible to successfully pyrolyze sugarcane trash, a process that was difficult to accomplish in the traditional fluidized-bed pyrolysis under inert atmosphere. Pyrolysis of the trash under the recycled atmosphere produced more non-condensable gases than liquid fuel, leading to about 18 wt% less oil than the eucalyptus. The biochar compositions resembled that of bituminous coal, with the exception of sugarcane trash char because of its high ash content.

Last Modified: 11/23/2014
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