Daniel Valdez, G.; Valois, F.P.; Bremer, S.J.; Bezerra, K.C.A.; Hamoy Guerreiro, L.H.; Santos, M.C.; Bernar, L.P.; Feio, W.P.; Moreira, L.G.S.; Mendonça, N.M.; de Castro, D.A.R.; Duvoisin, S., Jr.; Borges, L.E.P.; Machado, N.T. Improving the Bio-Oil Quality of Residual Biomass Pyrolysis by Chemical Activation: Effect of Alkalis and Acid Pre-Treatment. Energies2023, 16, 3162.
Daniel Valdez, G.; Valois, F.P.; Bremer, S.J.; Bezerra, K.C.A.; Hamoy Guerreiro, L.H.; Santos, M.C.; Bernar, L.P.; Feio, W.P.; Moreira, L.G.S.; Mendonça, N.M.; de Castro, D.A.R.; Duvoisin, S., Jr.; Borges, L.E.P.; Machado, N.T. Improving the Bio-Oil Quality of Residual Biomass Pyrolysis by Chemical Activation: Effect of Alkalis and Acid Pre-Treatment. Energies 2023, 16, 3162.
Daniel Valdez, G.; Valois, F.P.; Bremer, S.J.; Bezerra, K.C.A.; Hamoy Guerreiro, L.H.; Santos, M.C.; Bernar, L.P.; Feio, W.P.; Moreira, L.G.S.; Mendonça, N.M.; de Castro, D.A.R.; Duvoisin, S., Jr.; Borges, L.E.P.; Machado, N.T. Improving the Bio-Oil Quality of Residual Biomass Pyrolysis by Chemical Activation: Effect of Alkalis and Acid Pre-Treatment. Energies2023, 16, 3162.
Daniel Valdez, G.; Valois, F.P.; Bremer, S.J.; Bezerra, K.C.A.; Hamoy Guerreiro, L.H.; Santos, M.C.; Bernar, L.P.; Feio, W.P.; Moreira, L.G.S.; Mendonça, N.M.; de Castro, D.A.R.; Duvoisin, S., Jr.; Borges, L.E.P.; Machado, N.T. Improving the Bio-Oil Quality of Residual Biomass Pyrolysis by Chemical Activation: Effect of Alkalis and Acid Pre-Treatment. Energies 2023, 16, 3162.
Abstract
This work investigated the effect of temperature and acid or alkalis chemical activation by pyrolysis of Açaí seeds (Euterpe Oleraceae, Mart.) on the yield of bio-oil, hydrocarbon content of bio-oil, and chemical composition of aqueous phase. The experiments were carried out at 350, 400, and 450 °C and 1.0 atmosphere, KOH and HCl activation, in laboratory scale. The acidity of bio-oils and aqueous phases determined by AOCS methods, while the chemical composition of bio-oils and aqueous phase by GC-MS and FT-IR. The bio-char characterized by XRD. For the activation with KOH, the XRD analysis identified the presence of Kalicinite (KHCO3), the dominant crystalline phase in bio-char, while an amorphous phase was identified in bio-chars for the activation with HCl. The yield of bio-oil, for the pyrolysis of Açaí seeds activated with KOH, varied between 3.19 and 6.79 (wt.%), showing a smooth exponential increase with temperature. The acidity of bio-oil varied between 12.3 and 257.6 mgKOH/g, decreasing exponentially with temperature, while the acidity of aqueous phase lies between 17.9 and 118.9 mgKOH/g, showing and exponential decay behavior with temperature, demonstrating that higher temperatures favor not only the yield of bio-oil but also bio-oils with lower acidity. For the pyrolysis experiments activated with HCl, the yield of bio-oil varied between 2.13 and 3.37 (wt.%), decreasing linearly with temperature, while that of gas phase varied between 17.91 and 37.94 (wt.%), increasing linearly with temperature. The acidity of bio-oil varied between 127.1 and 218.5 mgKOH/g, increasing with temperature, showing that higher temperatures did not favor the yield of bio-oil and bio-oils acidity. For the chemical activation with KOH, the FT-IR analysis of bio-oils identified the presence of chemical groups characteristics of hydrocarbons and oxygenates, while that of aqueous phase only groups characteristics of oxygenates. For the chemical activation with HCl, the FT-IR analysis of bio-oil and aqueous phases identified only the presence of groups characteristics of oxygenates. For the experiments with KOH activation, the GC-MS of bio-oil identified the presence of hydrocarbons (alkanes, alkenes, cycloalkanes, cycloalkenes, and aromatics) and oxygenates (carboxylic acids, phenols, ketones, and esters). The concentration of hydrocarbons varied between 10.19 to 25.71 (area.%), increasing with temperature, while that of oxygenates from 52.69 to 72.15 (area.%), decreasing with temperature. For the experiments with HCl activation, the GC-MS of bio-oil identified only the presence of oxygenates. Finally, it can be concluded that chemical activation of Açaí seeds with KOH favors the not only the yield of bio-oil but also the content of hydrocarbons while activation with HCl produced bio-oils with only oxygen compounds.
Keywords
Açaí seeds; Chemical activation; Pyrolysis; Acidity; Liquid hydrocarbons
Subject
Engineering, Energy and Fuel Technology
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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