Drying performance of a direct-fired kiln developed in Mongolia
Smoke drying by means of a direct-fired kiln is considered to be one of the most cost-effective methods of drying lumber. In the present study, Siberian larch (Larix sibirica) lumber was dried using a direct-fired kiln developed in Mongolia. When approximately 500 kg of sawdust was used as fuel, the maximum and mean temperatures in the kiln were 78.2°C and 54.2°C for the lower side, respectively, while they were 70.4°C and 50.1°C for the upper side, respectively. The temperature inside the kiln was above 60°C for a duration of about 40 to 50 hours. The moisture content of the lumber decreased from 56.4% to 23.2%. No significant differences in terms of the mechanical properties were found between air- and smoke-dried wood. Based on these results it appears that the direct-fired kiln developed in Mongolia is useful for the low-cost drying of Siberian larch lumber, although improvements to the kiln and a prolonged drying schedule are needed in order to obtain more dried lumber.