Pyrolysis of Small Size Fuel Particles

In order to predict the pyrolysis of small size fuel particles, experiments are carried out in a thermogravimetric analyser (TGA). The product gases (CO, CO2, CH4, H2,...) are simultaneously determined by means of different gas analysers. Using the results of such experiments, kinetic parameters for primary pyrolysis reactions are calculated. The kinetic parameters are used in the computer program PARSIM which was developed at the institute. Until now different types of coal (Göttelborn, Ibbenbüren, Illinois, ...), different types of biomass (spruce wood, spruce bark, beech wood, cellulose, lignin) and plastics (PE, PP) have been analysed. Applying a combination of the TGA described above and a tubular reactor (quartz glass) it is possible to investigate cracking reactions of primary pyrolysis tar. By varying the temperature of the tubular reactor and the average residence time of the primary volatiles in the hot zone of the reactor, kinetic parameters for tar cracking are determined. This cracking of tar is particularly important for the thermochemical conversion of biomass because there "tar" is often undesirable since it can cause problems (e.g. gasification of biomass for the operation of gas engines). Up to now spruce wood, spruce bark, beech wood and birch wood have been investigated. Another research work is the investigation of the heat of pyrolysis of wood (in co-operation with the University of Pisa).