Over the past decades, a great deal of experimental work has been carried out on the development of pyrolysis processes for wood and waste materials. Pyrolysis is an important phenomenon in thermal treatment of wood, therefore, the successful modelling of pyrolysis to predict the rate of volatile evolution is also of great importance. Pyrolysis experiments of waste spruce sawdust were carried out. During the experiment, gaseous products were analysed to determine a change in the gas composition with increasing temperature. Furthermore, the model of pyrolysis was created using Aspen Plus software. Aspects of pyrolysis are discussed with a description of how various temperatures affect the overall reaction rate and the yield of volatile components. The pyrolysis Aspen plus model was compared with the experimental data. It was discovered that the Aspen Plus model, being used by several authors, is not good enough for pyrolysis process description, but it can be used for gasification modelling.

Effect of geometrical parameters on two phase hydrodynamics of airlift reactor is the main topic of present paper. Laboratory scale apparatus with internal circulation loop consists of concentric draft tube, in which a gas bubbles rising. Setup of draft tube inside of reactor is important geometry parameter and has big influence on two phase hydrodynamics. In experiment was studied influence of changes diameter of draft tube to hydrodynamics in airlift reactor. Results of experiments (liquid velocity and gas hold-up) were compared with the simple CFD simulations performed in COMSOL Multiphysics 3.5a. For each point of gas volumetric flow in simulation, were determined conditions of bubble diameter and bubble drag coefficient. Although bubble break-up and coalescence were neglected, the results of numerical simulation are in pretty good agreement with experimental data.Peer reviewe