Autothermal reforming of palm empty fruit bunch bio-oil: thermodynamic modelling

This work focuses on thermodynamic analysis of the autothermal reforming of palm empty fruit bunch (PEFB) bio-oil for the production of hydrogen and syngas. PEFB bio-oil composition was simulated using bio-oil surrogates generated from a mixture of acetic acid, phenol, levoglucosan, palmitic acid and furfural. A sensitivity analysis revealed that the hydrogen and syngas yields were not sensitive to actual bio-oil composition, but were determined by a good match of molar elemental composition between real bio-oil and surrogate mixture. The maximum hydrogen yield obtained under constant reaction enthalpy and pressure was about 12 wt% at S/C = 1 and increased to about 18 wt% at S/C = 4; both yields occurring at equivalence ratio Φ of 0.31. The possibility of generating syngas with varying H2 and CO content using autothermal reforming was analysed and application of this process to fuel cells and Fischer-Tropsch synthesis is discussed. Using a novel simple modelling methodology, reaction mechanisms were proposed which were able to account for equilibrium product distribution. It was evident that different combinations of reactions could be used to obtain the same equilibrium product concentrations. One proposed reaction mechanism, referred to as the ‘partial oxidation based mechanism’ involved the partial oxidation reaction of the bio-oil to produce hydrogen, with the extent of steam reforming and water gas shift reactions varying depending on the amount of oxygen used. Another proposed mechanism, referred to as the ‘complete oxidation based mechanism’ was represented by thermal decomposition of about 30% of bio-oil and hydrogen production obtained by decomposition, steam reforming, water gas shift and carbon gasification reactions. The importance of these mechanisms in assisting in the eventual choice of catalyst to be used in a real ATR of PEFB bio-oil process was discussed

Conversion of levulinic acid to valuable chemicals: a review

Levulinic acid (LA), a class of important chemical intermediates and new energy chemicals, has been considered one of the top-12 platform compounds that can be converted from biomass resources. Substantial progress on the conversion of lignocellulose biomass to LA and the further conversion of LA to high value downstream chemicals have been achieved recently. This review summarizes the preparation and separation processes of LA firstly, and then, emphatically discusses the catalytic system for LA conversion to valuable downstream products, including levulinate esters, 2-methyl tetrahydrofuran (MTHF), Gamma-valerolactone (GVL), 5-aminolevulinic acid (DALA), and diphenolic acid (DPA). An outlook is provided at the end of this paper to highlight the challenges and opportunities for the comprehensive utilization of lignocellulose biomass. (c) 2021 Society of Chemical Industry (SCI)