title: Thermolysis of microalgae and duckweed in a CO₂-swept fixed-bed reactor: bio-oil yield and compositional effects.
abstract: Microalgae and duckweed were grown and harvested over a three-month period in CO(2)-sparged helioreactors and open earthen ponds, respectively. The biomass feedstocks were thermolyzed in a thermogravimetric analyzer (TGA) and fixed-bed reactor to produce a fuel precursor coined "bioleum". Analysis of the thermolysis kinetics revealed an increase in the activation energy with heating rate for both aquatic species. Activation energies were lower than literature-reported values for lignocellulosics, corroborated by TGA thermolysis of pinewood. Thermolysis of microalgae resulted in higher bioleum and energy yields than for duckweed, reflecting differences in the biomass composition. The algal bioleum properties resemble those of crude petroleum except for higher nitrogen and oxygen content and acid number. Speciation identified 300+ compounds in the oil phase, with similar amounts of hydrocarbons and oxygenates, while acetic acid was the major species in the aqueous phase. The compounds were classified according to their degree of aromaticity, oxygenation, and nitrogenation.
authors.affiliation: Department of Chemical & Biomolecular Engineering, University of Houston, Houston, TX 77204-4004, United States.
authors.forename: Alejandrina
authors.initials: A
authors.lastname: Campanella
authors.forename: Rachel
authors.initials: R
authors.lastname: Muncrief
authors.forename: Michael P
authors.initials: MP
authors.lastname: Harold
authors.forename: David C
authors.initials: DC
authors.lastname: Griffith
authors.forename: Norman M
authors.initials: NM
authors.lastname: Whitton
authors.forename: Robert S
authors.initials: RS
authors.lastname: Weber
mesh_terms: D029064:Araceae / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D056804:Biofuels / Q000032:analysis*; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D001709:Biotechnology / Q000379:methods*; D002245:Carbon Dioxide / Q000494:pharmacology*; D004055:Differential Thermal Analysis; D007700:Kinetics; D008031:Lignin / Q000737:chemistry; D058086:Microalgae / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D009821:Oils / Q000032:analysis; D010578:Petroleum / Q000032:analysis; D013696:Temperature; D013818:Thermogravimetry; D013997:Time Factors
chemical_list: D056804:Biofuels; D009821:Oils; D010578:Petroleum; C036909:lignocellulose; D002245:Carbon Dioxide; D008031:Lignin