Abstract
With increasing political and environmental concerns, it becomes imperative to develop efficient processes in economic and energy terms for the sustainable production of fuels and chemical products. Hydrothermal liquefaction (HTL) is a process for the transformation of organic materials such as bio-waste or biomass into crude oil at temperatures usually below 400°C under moderate to high pressures (5–25 MPa) in the presence of water and, depending on the process, of a catalyst. In this context, it is important to understand the behavior under thermal degradation of the material of interest under inert atmosphere, in order to investigate the possibility of breaking the initial polymer chains into smaller molecules during heating. In under high pressures, this small molecules can be converted into new products of higher molecular weight. In the present work the thermogravimetric (TG) behavior under inert atmosphere of pure green coconut fiber and mixtures thereof with a spinel phase (Fe2CoO4) as catalyst (50% w/w) has been studied. The spinel phase has been produced at 1000°C and different calcination times (3h, 6h and 9h). The materials involved in the present research were characterized through different techniques, such as scanning electron microscopy, X-ray diffraction and Infrared Absorption Spectroscopy. According to the TG data, the catalyst produced for a calcination time of 9h showed a superior behavior regarding the full thermal degradation of the lignine present, which developed through a new mechanism, without the formation of fixed carbon. The results further suggest that the mixing process has a significant effect over the measured degradation kinetics. The kinetic modelling applied to the dynamic TG signal allowed a quantitative representation of the experimental data. The activation energy obtained was 85.291 kJ / mol and the order of the reaction was 0.1227.
