The present paper deals with the pyrolysis of Finnish milled peat with different residence times in the laboratory-scale drop tube reactor. Based on the experimental results, the kinetic parameters for Finnish milled peat are determined and some important properties of the reactor and peat are identified using optical measurement techniques. Furthermore, it is demonstrated that in drop tube reactors the drag coefficient of the fuel particle might be a major source of error. (c) 2007 Elsevier Ltd. All rights reserved.