Influence of temperature on products from fluidized bed pyrolysis of wood and solid recovered fuel

Abstract The fluidized bed fast pyrolysis of two different kinds of fuels, namely, wood pellets (WP) and solid recovered fuel (SRF) pellets made up of a municipal solid waste by ECONWARD TECH, S.L. (EP) has been carried out. Thus, the analysis of the influence of pyrolysis reactor temperature (600–800 °C) and fuel type in terms of product distribution, e.g. gases, char and tar has been performed. The conditions used in this work are of special interest for the gasification in fluidized beds, in which fast pyrolysis plays a relevant role as it is the first step of fuel conversion. The gas composition was continuously recorded and the tar samples collected during the experiments were analyzed by GC technique. The higher ash content in the EP enhanced charring and decarboxylation reactions, which greatly influenced the distribution of the gaseous products leading to a high CO2 yield. Tar composition was also affected by the constituents of the fuels used, with the content of phenolic compounds in the EP tar obtained at 650 °C being particularly low at the expense of a higher light aromatic content. The rise in temperature decreased the fraction of phenolic compounds and led to a gradual formation of light and heavy polycyclic aromatic hydrocarbons (PAHs), with naphthalene being the major compound in tars of both fuels, WP and EP, at high temperature. The results can be used to derive pyrolysis sub-models for fluidized bed gasification modeling.