| 1. |
- Andersson, Jan-Erik, et al.
(författare)
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Energy mapping in the sawmill industry with focus on drying kilns
- 2013
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Konferensbidrag (refereegranskat)abstract
- The forest industry stands for approximately 11 % of Sweden’s total export. However, the forest industry is energy intensive. In 2008, sawmill industry alone consumed almost 8,7 TWh of energy, corresponding to 5 % of the Swedish industries total energy consumption. Out of their total consumption, 2200 GWh was electric power, 194 GWh heating oil , 4229 GWh bio-fuel, 574 GWh district heating, and other fuels such as diesel 1503 GWh [1].The project ”EESI- Energy Efficiency in the Sawmill Industry” was started in the spring of 2010 with the aim of demonstrating the possibilities to reduce the energy consumption in the sawmill industry with 20 % by 2020. 16 sawmill corporations and 14 equipment suppliers has joined the project which is carried out in two phases of which the first phase was carried out during 2010 and 2011. EESI has now reached half time and the first energy-saving implementations have been completed at the participating sawmills.This paper presents the energy-mapping, measurements and modelling performed by the participating sawmills during the first phase of the project [2, 3]. The average energy consumption per sawn cubic metre of boards varied between approximately 300 to 500 kWh/m3. Out of this, the electricity consumption was on average 85 kWh/m3, bio-fuel 290 kWh/m3 and diesel 1.8 l/m3.However, the main concern from sawmills regarding energy consumption was the wood drying process. The striking results from the preliminary measurements were the large variation in energy consumption even with similar drying kilns. This was especially apparent for the heat consumption in kiln dryers which could vary as much as 50 % for the same dimension of spruce planks.The results from the first phase of the project resulted in a large number of actions in order to reduce the energy consumption which are now being implemented or have already been completed. Examples of those actions are: simplified management system adapted to sawmills, weighing of packages for more accurate wood drying, reduced speed or intermittent operation of the air circulating fans in batch kilns and moisture content measurements of bio-fuel.References[1] Statistiska centralbyrån (SCB), 2013, Industrins årliga energianvändning 2011, Slutliga uppgifter, EN23SM1301, ISSN 1654-367X. (In Swedish). [2] Andersson, J-E., Lycken, A., Nordman, R., Olsson, M., Räftegård, O., and Wamming, T. State of the art – Energianvändning i den svenska sågverksindustrin. SP Rapport 2011:42, ISBN 978-91-86622-72-5. (In Swedish).[3] Andersson, J-E., Räftegård, O., Lycken, A., Olsson, M., Wamming, T., and Nordman, R. Sammanställning av energimätningar från EESI fas 1. SP Rapport 2011:41, ISBN 978-91-86622-71-8. (In Swedish).
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| 2. |
- Couceiro, José, 1983-, et al.
(författare)
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In Situ CT-Scanning of Checking and Collapse Behaviour of Eucalyptus nitens During Drying
- 2016
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Ingår i: Proceedings of the 59th International Convention of Society of Wood Science and Technology March 6-10, 2016 – Curitiba, Brazil.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Eucalyptus nitens has become a commercially important species in Chile and it isrepresenting one of the fastest growing wood-stock in the country. Today, it is widelyused for pulp and paper production, but the interest in using the solid wood has increasedin recent years. Before the sawn timber can be utilized, its moisture content must bereduced. Often during drying, hydrostatic tension forces within the cell exceed thecompressive strength of the thin cell wall of Eucalyptus nitens and the cell collapses. Thisphenomenon usually leads to severe surface deformation and both surface and internalcracks (honeycombing). Yield and quality of the final product, and thereby sawmills’profitability, are decreased by these cracks and deformations. The aim of this study wasto investigate, by CT-scanning samples throughout the drying process, if it is possible todetect when and how cracking and deformation occurs and develops in specimens ofEucalyptus nitens from Chile. Based on this knowledge, better drying schedules canhopefully be developed to improve the yield and provide a higher end-quality of the sawntimber.
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| 3. |
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| 4. |
- Couceiro, José, 1983-, et al.
(författare)
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The conditioning regime in industrial drying of Scots pine sawn timber studied by X-ray computed tomography : a case-study
- 2020
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Ingår i: European Journal of Wood and Wood Products. - : Springer. - 0018-3768 .- 1436-736X. ; 78:4, s. 673-682
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Tidskriftsartikel (refereegranskat)abstract
- Industrial drying of sawn timber is a process driven by a difference in moisture content (MC) between the core and the surface as moisture moves from the wet inner region towards the drier surface. After drying, the timber surface is always drier than its core, and stresses have developed within the wood volume. If the timber is to be further processed, these stresses and the moisture gradient need to be reduced to avoid unwanted distortion, i.e. the timber needs to be conditioned. Conditioning is usually accomplished by exposing the timber to a hot and humid climate after the drying regime. The conditioning regime is essential for timber quality, and it is energy and time consuming; therefore of interest for optimisation. This research was a case study where for the first time the MC during conditioning was studied in an X-ray computed tomography (CT) scanner. The aim was to test a previously developed algorithm and investigate the influence of MC and heartwood-sapwood proportion on the effectivity of the moisture equalisation in 30 mm thick Scots pine boards. The MC was estimated from CT data acquired during the drying and conditioning of the boards in a lab-scale kiln adapted to a medical CT scanner. Results show that the algorithm can provide relevant data of internal MC distribution of sawn timber at the pixel level. Furthermore, for the drying schedules studied, the conditioning at low MC (8%) does not need to be longer than 3 h, while higher MC (18%) requires a longer conditioning.
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| 5. |
- Eriksson, Joakim, et al.
(författare)
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5G i träindustrin
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Privata 5G nätverk – antingen som en del av ett publikt eller som ett helt eget mobilnät erbjuder möjliga lösningar på ett antal av de utmaningar som finns kring WiFi och trådlösa uppkopplingar i logistik och produktion. Tekniken börjar bli väletablerad och antalet leverantörer ökar snabbt samtidigt som priser för infrastrukturen sjunker i pris. Förutom att femte generationens mobilnät löser problem kring mobilitet och uppkoppling så finns ett antal intressanta funktioner såsom positionering och standardiserad edge computing för lokala digitala tjänster. Dessa funktioner bör dock ses som en del av en framtida uppgradering snarare än något som finns tillgängligt idag (dock inte så långt bort in i framtiden). Alla de besökta sågverken hade liknande utmaningar kring trådlös uppkoppling och i vissa fall har även 4G-baserade lösningar börjat användas – med gott resultat.Tyvärr fick vi inte konkreta priser från de operatörer och leverantörer som dialog fördes med men via vissa leverantörer kan man ändå få en viss indikation (se t ex AWS erbjudande där det för ett privat nät med två radioaccespunkter ligger på ca 140 KSEK / månad totalt).
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| 6. |
- Granlund, Alexander, et al.
(författare)
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Evaluation of Snow Removal Methods for Rooftop Photovoltaics
- 2022
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Konferensbidrag (refereegranskat)abstract
- Avoiding snow on photovoltaic (PV) installations is motivated for two reasons: to decrease power losses from shading, or to decrease mechanical loads to avoid damage to the PV-installation and the underlying construction. We experimentally investigated the effectiveness and suitability of four different snow removal methods at our facility in the north of Sweden (Piteå, 65°N), throughout three winters. The layout of a PV installation and the underlying roof, together with meteorological conditions and snow characteristics, impact which methods are best suited for snow removal. A simple roof rake with a rectangular toolhead works well when the snowpack is compact and not too thick, whereas a roof rake with a slide works better when the snow is dry and packed. Neither the investigated passive hydrophobic surface coatings, nor the active forward bias electrical heating methods induced shedding of the accumulated snowpack in our experiments without additional intervention. At our test facility in Piteå, the roof rake with a slide was the most effective and user-friendly snow removal. Despite maximum snow loads of approximately 1 kPa, far below the modules’ rating, cell damage was observed for both snow removal groups (except for the slide roof rake group) and the control group.
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| 7. |
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| 8. |
- Grönlund, Anders, et al.
(författare)
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Monitoring lumber size, shape and mismatch in double-arbour saws-Development and validation of scanning equipment
- 2009
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Ingår i: Proceedings of the 19th International Wood Machining Seminar. - Nanjing : Nanjing Forestry University. - 9787502362249 ; , s. 222-227
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Konferensbidrag (refereegranskat)abstract
- The costs for raw material amount to about 70% of the total costs for most sawmills. Consequently, it is very important to improve the saw yield for the economy and competitiveness of sawmills. The aim of an ongoing project in Sweden is to build knowledge and develop methods and techniques that enable an increase of the sawing yield. The idea is that the yield increase will be achieved through thinner kerfs, adapted shrinkage allowance and lower sawing allowance. One key parameter in the sawing process is sawing accuracy. We have as a part of the ongoing project developed scanning equipment with which we can measure the size and geometry of the produced lumber. The equipment is an off line research apparatus based on two laser triangulation devices.The industrial partners on the project have especially pointed out that a method is needed for measurement and evaluation of the mismatch on sawn surfaces produced by double arbour saw machines. The equipment has a measurement resolution that is better than 0.1 mm in the thickness direction and can measure thickness and width with a repeatability of 0.1 mm and bow, crook, twist and cup with a repeatability of < 1 mm. As there is no standard for measurement and evaluation of mismatch, a special algorithm for this parameter has been developed and correlated against subjective judgements of skilled personnel from the sawmill industry. The correlation between manually judged mismatch and mismatch measured by the scanner was 0.76.
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| 9. |
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| 10. |
- Hägg, Linus, et al.
(författare)
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Influence of Fan Speed on Airflow distribution in a Scandinavian Drying Kiln
- 2012
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Konferensbidrag (refereegranskat)abstract
- From the beginning of the 90’s the development of drying kilns in Scandinavia has been focusing on increased drying capacity and also making the kilns more flexible in terms of handling differences in dimensions and initial moisture content. In order to facilitate the demand of higher airflows there has been an increase in circulation fan capacity. In a sawmill with modern kilns the fan capacity in a single batch kiln can be over 90 kW, making the drying kiln fans the single biggest consumer of electric power.Today, more and more sawmills are reviewing their consumption of electric power due to increasing prices. One way of reducing the consumption is to reduce the fan speed when the moisture content is so low that the drying rate is mainly limited by the diffusion properties of the wood and not the airflow. Since modern kilns are designed for high capacity fans there is a lack of knowledge of how a reduced fan speed affects the airflow distribution. This poses a risk of getting reduced quality of the final product due to increased moisture content variation in a batch.In this study the airflow has been measured inside an industrial drying kiln. For this study two experiments were done with 20 airflow gauges placed inside a kiln. During both experiments the kiln was fully loaded with pre dried Scotts pine (Pinus sylvestris) boards with a thickness of 50 mm. The reason for using pre-dried boards was simply that the gauge was not able to withstand the climate produced during a real process. In order to cover as much of the kiln as possible the gauges were distributed differently for the two experiments.The results show that about 30 % of the total airflow passes through the bolster spaces which are only about 20 % of the total flow area. This means that a notable volume of air might not be participating in drying of the boards.The results show also that the relative airflow distribution between the middle and the side of board stacks becomes more heterogeneous at a low fan speed. This trend is also seen for the relative distribution of airflow between bolster and sticker spaces.
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