Compression Kiln Research &amp; Development FOR: Forest Enterprises Australia Ltd.
Creators: name: Fairclough, Duncan T.
Publisher: name: The University of British Columbia
Year: 2011

description: With growing competition in the timber processing industry in Australia, forestry companies are forced to look for new and innovative technologies to remain competitive. Forest Enterprises Australia (FEA) is dedicated to sourcing new equipment and technologies that can improve their various product lines whether it is in their plantations or their timber processing facilities. FEA’s timber division is specifically committed to always improving their product line with their in-house research and development department. Attempting to utilize the TeknoComp compression kiln is just another example of FEA’s commitment to finding innovative ways to produce timber. The focus of this study was to determine the feasibility of using the compression kiln. Prior to this study there had been some drying tests done on E. nitens in the compression kiln. The bulk of these tests were done at lower temperature ranging from 60°C to 100°C. The overall results from the testing were not very promising as much of the timber was not dry. When the timber was dry it usually contained severe collapse and checking both on the surface and internally. During these tests there was no way of tracking the drying conditions inside the kiln due to the software not allowing for data to be downloaded. For this study the bulk of the E. nitens timber was dried at higher temperatures than that of the previous trials, temperatures ranged from 70°C to 140°C. For the study the software was changed so the data for the various kiln parameters could be downloaded. This allowed for kiln parameters such as dry bulb, wet bulb, dew point, and relative humidity to be tracked. From this it was determined that the kiln was capable of recreating similar drying conditions for charges with the same schedule. During the study it was possible to obtain acceptable values for moisture content in the timber however, the timber was still prone to many defects mostly collapse and checking. It was often found that even timber that had excellent surface quality still contained internal checking when the timber was cross sectioned. Overall the results for drying E. nitens from green were not promising. Three mainland species were also selected for drying in the compression kiln E. dunnii, E. saligna, and E. sieberi. The species were selected based on the hopes that their natural properties would achieve a better result. Drying schedules used for these species were very similar to those of E. nitens. When compared to the E. nitens boards there was some improvement in quality however E. dunnii and E. saligna were both prone to surface and internal checking as well as collapse. E. sieberi did show some very promising results even though it was only done in small quantities. It appeared that the species was much less prone to surface and internal checking as very little of these defects appeared in any of the test samples. Collapse in E. sieberi was almost nonexistent. The final species to be tested was pine. The results from this trial were promising as the final dried quality of the timber was quite good. Drying temperatures ranged from 100°C to 140°C with drying times of 15 to 24 hours. The main problem came from the cost of drying the pine in the compression kiln versus the value of the timber as the pine that was dried was a low valued product (100x38mm heartwood). Unfortunately due to time restrictions it was not possible to test larger section pine that could be sold as a high value product. This would be a good starting point if further trials of drying pine in the compression kiln were to be done. Throughout the study there were various difficulties running the kiln mainly due to equipment failure. Building the timber stacks proved to be quite difficult due to the Joulin stacking machine often dropping the timber. Also the hydraulic systems inside the kiln used to compress the stacks and drive the conveyors were in desperate need of maintenance causing difficulties during the study. There was also the issue of the kiln constantly tripping breakers causing the kiln to shutdown in the middle of a drying charge. If the kiln were to be put back into production thorough maintenance would need to be completed.