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- Sehlstedt-Persson, Margot, 1957-, et al.
(författare)
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Virkestorkning Sammanfattande projektrapport : IPOS –Svenskt trä-Innovationspotential för det biobaserade samhället Delprojekt 2 – Behovsstyrd förädling av Svenskt Trä Delområde Torkning
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Projektet som helhet har bidragit till att steg har tagits mot målet att uppnå en snabbare och mer energieffektiv torkningsprocess som är mer självstyrande och automatiserad med bättre och jämnare torkningskvalitet, vilket sammantaget minskar torkkostnaderna.Projektet har behandlat ett antal delstudier kopplat till industriell virkestorkning. I projektet har studier utförts i såväl i tomograf (CT) i labskala som i industriella fullskaleförsök. I samråd med den industriella arbetsgrupp, som förutom utförare från LTU och RISE har ingått i projektet, beslöts vid det uppstartsmöte som hölls i november 2018 att prioritera ett antal delstudier att ingå i projektet. Efterhand har mindre arbetsgrupper med deltagare från industrin knutits till de olika delstudierna beroende på företagens specifika intresseområden. De delstudier som ingått i projektet är följande:1) Uppvärmningsfasen vid torkning av granbräder. Inledande studier i CT med uppföljning i industriell fullskala.2) Optimering av reverseringsintervall i kammare. Uppföljning av torkkvalitet i justerverksdata som feedback till torkprocessen. Studie i industriell fullskala.3) Tid I diffusionsfas efter effektras vid kammartorkning av granbräder. Uppföljning av torkkvalitet i justerverksdata som feedback till torkprocessen. Studie i industriell fullskala med uppföljning i labskala i CT.4) CT-studier av konditioneringssteget efter värmebehandling enligt ThermoWood processen. 5) CT-studier av fuktdynamik vid oscillerande torkningsklimat.6) Analys av CT-data vid konditionering av virke. Beräkning av fuktgradient från två tidigare projekt. Separata arbetsrapporter från delstudier 1,2,4.5 och 6 finns som bilagor till denna sammanfattande projektrapport.
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| 4. |
- Grönlund, Anders, et al.
(författare)
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Adaptive control of green target sizes
- 2009
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Ingår i: Proceedings of the 19th International Wood Maching Seminar. - Nanjing : Nanjing Forestry University. - 9787502362249 ; , s. 87-94
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Konferensbidrag (refereegranskat)abstract
- In Swedish sawmills, about 70% of the total costs can be derived from raw-material costs. Hence, it is very important for sawmills to obtain the highest possible yield. The green target size is an important parameter that affects the yield. The nominal size, sawing allowance, shrinkage allowance and planer allowance add up to the green target size that is needed when sawing lumber. We have, in this work, studied whether it is possible to adaptively control the green target size by measuring log density and annual ring width with an X-ray Log Scanner online. Our hypothesis was that density and growth speed will affect how much every single piece of lumber will shrink.The results show that both density and annual ring width are rather weak variables for prediction of lumber shrinkage. The variable "distance to pith", i.e., where in the log cross-section a piece of lumber has been cut, has proved to be a significant variable for prediction of lumber shrinkage. The results show that the yield can be considerably improved by adapting the green target size to how far from the pith every piece of lumber is cut.
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| 5. |
- Grönlund, Anders, et al.
(författare)
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Adaptive control of green target sizes
- 2009
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Ingår i: Proceedings of 19th International Wood Machining Seminar.. - : Nanjing Forestry University the IWMS-19 Organizing.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Johansson, Pernilla, et al.
(författare)
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Mould growth on kiln-dried and air-dried timber
- 2013
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Ingår i: European Journal of Wood & Wood Products. - : Springer Science and Business Media LLC. - 0018-3768 .- 1436-736X. ; 71:4, s. 473-481
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Tidskriftsartikel (refereegranskat)abstract
- The problem with discoloration, due to fungal growth, of wooden outdoor constructions seems to have increased in recent years. One reason for this increase might be an impact of new drying methods of timber. Modern kiln drying methods use high temperatures in an effort to shorten the drying process, which leads to fast capillary water transport and subsequently redistribution and accumulation of dissolved substances at the surface. These can then be used as nutrients by fungi. In this study, wood was dried according to different simulated drying schedules. The mould resistance of the timber was then tested. Wood dried at room temperature was used as a reference. No differences could be confirmed at the end of the test; mould growth was extensive on all the samples. However, mould growth started earlier on the kiln-dried samples than on air-dried timber. As for the discolouring fungus, there was a clear difference between wood dried at room temperature and kiln-dried wood, though no difference could be established between the two artificial methods.
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- Salin, Jarl-Gunnar, et al.
(författare)
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Drying of timber in progressive kilns : Simulation, quality, energy consumption and drying cost considerations
- 2008
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Ingår i: Wood Material Science & Engineering. - 1748-0272 .- 1748-0280. ; 3:1-2, s. 12-20
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Tidskriftsartikel (refereegranskat)abstract
- Progressive (semi-continuous) kilns for softwood drying are very common in Finland and Sweden and are used in some other countries too. A simulation program has been developed that covers all three types of this kiln. The program calculates the climate in the length direction of the kiln and moisture content, moisture profile, wood temperature, slicing test gap and stress development. Energy consumption and drying costs may also be determined. The temperature level is the most important parameter regarding kiln efficiency. Two-zone progressive kilns are found to be more efficient than single-zone kilns. Progressive kilns have lower energy consumption and drying costs than batch kilns. Experimental full-scale tests show that the timber quality from a progressive kiln is comparable to, or in some cases even better than, timber dried in batch kilns
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