Effect of particle size and temperature on woody biomass fast pyrolysis at high temperature (1000-1400 degrees C). Fuel, Elsevier, 2012, 97, pp.

Solid char is a product of biomass pyrolysis. It contains a high proportion of carbon, and lower contents of H, O and minerals. This char can have different valorization pathways such as combustion for heat and power, gasification for Syngas production, activation for adsorption applications, or use as a soil amendment. The optimal recovery pathway of the char depends highly on its physical and chemical characteristics. In this study, different chars were prepared from beech wood particles under various pyrolysis operating conditions in an entrained flow reactor (500-1400 • C). Their structural, morphological, surface chemistry properties, as well as their chemical compositions, were determined using different analytical techniques, including elementary analysis, Scanning Electronic Microscopy (SEM) coupled with an energy dispersive X-ray spectrometer (EDX), Fourier Transform Infra-Red spectroscopy (FTIR), and Raman Spectroscopy. The biomass char reactivity was evaluated in air using thermogravimetric analysis (TGA). The yield, chemical composition, surface chemistry, structure, morphology and reactivity of the chars were highly affected by the pyrolysis temperature. In addition, some of these properties related to the char structure and chemical composition were found to be correlated to the char reactivity.

International audienceThere are many different ways to convert biomass into liquid fuels, mostly referred to as bio-oils. This paper presents the analysis of bio-oils produced by hydrothermal liquefaction and fast pyrolysis of beech wood. Both processes have a wide panel of parameters that can be optimised influencing the oil quality. Results of the analysis show that both oils have high acidities. Iodine values indicate a high degree of unsaturations. These two qualities seem to be inversely proportional in the case of pyrolysis oils. In the case of hydrothermal conversion, additives to adjust the pH such as sodium hydroxide increase oil yields, lower its viscosity but do little to further improve the quality of the oils. For pyrolysis oils, increasing the severity does reduce acidity but at the expense of more unsaturations and a loss in yield. The results show that without extensive upgrading or refining, commercial fuel standards cannot be met. Specific norms and standards are being elaborated for pyrolysis used in specific installations. This paper shows how detailed analysis can help to optimise process parameters with an objective that goes beyond the mass or energy yield. (c) 2016 Elsevier Ltd. All rights reserved