Measurements of the dependence of wood’spermeability to air on the temperature of the pyrolysis

The paper deals with the wood’s (in this case pine) longitudinal permeability to air and its possible dependence on the temperature of the pyrolysis. The measurement of permeability was indirect and conducted on the original stand constructed solely for this purpose. Before every measurement a special sample preparation procedure was conducted for each sample group. Every group of samples was preheated up to the temperature previously set in the oxygen-less environment. After that, samples were cooled down to the room temperature. The following parameters were measured directly: sample length and diameter, pressure difference, and time. After numerous measurements of the mentioned values, the permeability of wood to air was calculated using the Darcy’s law for a given pyrolysis temperature. The results show a distinct dependence between the wood’s permeability to air and the pyrolysis temperature. The minimum value of the permeability is on the level of 0.56 D for temperature of 50 ◦C and is growing up to the value of 5.8 D (over ten times of the initial value) for the temperature of 350 ◦C.