Slow pyrolysis experimental investigation on the tar formation and its pyrolysis behavior characteristics

The problems of safety, environment and cost caused by biomass tar hinder the development of biomass-tosyngas technology. In this paper, the characteristics of biomass tar formation and pyrolysis behavior were studied by using a tubular furnace and a thermogravimetric analyzer. The activation energy and pyrolysis mechanism function of different pyrolysis tar samples were determined. Results indicated that phenols, furancontaining structures, ketones and other oxygen-containing organic compounds were the main components. The tar yield reached its maximum at 700 degrees C. Before 500 degrees C, the change of tar composition was mainly related to the decomposition of biomass structure. After 500 degrees C, the tar underwent homogeneous transformation, and after 700 degrees C, the secondary reaction of tar intensified. Among the three stages of tar pyrolysis, the first stage had the largest mass loss. And the pyrolysis mechanism functions followed by first stage of the two different tar were obviously different. 600 degrees C pyrolysis tar followed the Diffusion model, while 800 degrees C pyrolysis tar followed the Order of reaction model.