Biyokütlenin Bor Katalizörleri Varlığında Hidrotermal Dönüşümü

Abstract

The conversion of biomass into liquid fuels and/or valuable products via hydrothermal processing is an important thermochemical process. The advantages of this process are its applicability for high-moisture-content bio-mass, ability to co-process the biomass with waste materials, use of lower temperatures than processes such as pyrolysis, and high energy efficiency. Hydrothermal conversion of biomass has been the objective of extensive research in recent years. Especially, there has been a continuing increase in the number of researches concerning the use of catalysts in the hydrothermal processing of biomass. In this study, we report the results of the conversion of woody biomass (Scotch pine and Oriental beech) using colemanite (CaB3O4(OH)3·H2O), sodium perborate monohydrate (NaBO3.H2O), disodium octaborate tetrahydrate (Na2B8O13.4H2O) and boric acid (H3BO3) as catalysts. The experiments were carried out under sub-critical water conditions at 250, 300, and 350°C and the corresponding pressures of these temperatures (4.0, 8.5, 16.5 MPa). To compare and evaluate the catalytic performance of the boron compounds, the experiments were also performed under identical conditions without any catalysts. The effect of catalysts on the product distributions and bio-oil compositions were investigated. The bio-oils obtained by hydrothermal process were analyzed by a gas chromatograph-mass spectrometer (GC-MS). Characterization of the catalysts were done by Brunauer-Emmett-Teller (BET) surface area and X-ray diffraction (XRD) analysis. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) analysis of the bio-oils obtained using colemanite, which showed a high catalytic activity in terms of bio-oil yield, were also carried out. The bio-chars obtained at 300°C with colemanite were characterized by scanning electron microscopy (SEM).