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Optimization of Bio-oil Production from Pyrolysis of Whole Algal Biomass
Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.orgCitation: Paper number 131594738, 2013 Kansas City, Missouri, July 21 - July 24, 2013. (doi: http://dx.doi.org/10.13031/aim.20131594738) @2013
Authors: Monet Concepcion Cadavillo Maguyon, Sergio C Capareda
Keywords: pyrolysis Nannochloropsis oculata microalgae bio-oil char.
Abstract. The extent of bio-oil production from pyrolysis of Nannochloropsis oculata was investigated at varying temperatures (400, 500, 6000C) and pressures (0, 50, 100 psig) to establish operating conditions that optimizes bio-oil yield. The effects of temperature and pressure on bio-oil, biochar and gas yields were also evaluated. The pyrolysis products obtained at optimum temperature and pressure were characterized to determine their potential usages. Results showed that lower temperatures (4000C) maximizes biochar production (56% wt), whereas, high temperatures (6000C) and pressures (100 psig) increase gas yield (20% wt). Maximum liquid production (43% wt) was obtained at 5400C and 0 psig. The liquid product consisted of two immiscible fractions: (1) yellowish aqueous fraction (20% wt), and (2) dark-brown organic bio-oil fraction (23% wt). At 5400C and 0 psig, biochar and syngas yields were approximately equal to 32% wt and 12% wt , respectively. The bio-oil obtained at optimum conditions has high carbon (72% wt) and hydrogen (10% wt) contents which contributed to its high energy content (36 MJ/kg). Chemical characterization using GC-MS showed that algal bio-oil contains alkanes (35.22%), alkenes (38.17%), alkynes (0.61%), alcohols (4.47%), acids (4.93%), benzenes and aromatic compounds (6.01%), esters (0.56%), amides (0.35%) and nitriles (9.68%) which indicates that algal bio-oil could be a potential replacement for crude oil after further processing. Biochar and syngas, on the other hand, also contain considerable energy contents of about 20 MJ/kg and 21MJ/m3, respectively which indicate that these products can also be used as alternative energy sources.