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- 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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- Bengtsson, Cecilia, 1974, et al.
(författare)
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Utilization of excess heat in the pulp and paper industry - a case study of technical and economic opportunities
- 2002
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Ingår i: Applied Thermal Engineering. - 1359-4311. ; 22:9, s. 1069-1081
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Tidskriftsartikel (refereegranskat)abstract
- Newly developed methods and tools based on pinch technology are used in a case study to investigate the potential and economy of using excess heat for pre-evaporation of chemo thermo mechanical pulp effluent and heat pumping in an integrated pulp and paper mill. The new tools give information about the system that traditional pinch tools such as the grand composite curve or the composite curves would not reveal. For example, the highest temperature levels possible where excess heat can be released are identified together with the amount of excess heat at each temperature level. The new curves are also able to provide information about where heaters and coolers are placed in an existing system. The matrix method has been used successfully in order to find an economically feasible heat exchanger network retrofit for the release of the excess heat found with the curves.The results of the case study show that a pre-evaporation plant can be integrated with the overall process with just a few modifications in the existing process. There are also opportunities for heat pumping in the system. Both projects have a pay-back period shorter than required for implementation.
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- Björk, Kaj-Mikael, et al.
(författare)
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Solving large-scale retrofit heat exchanger network synthesis problems with mathematical optimization methods
- 2005
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Ingår i: Chemical Engineering and Processing: Process Intensification. - : Elsevier BV. - 0255-2701. ; 44:8, s. 869-876
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Tidskriftsartikel (refereegranskat)abstract
- Heat exchanger network optimization is a standard problem in process design. Various mathematical models and heuristics have beendeveloped to help the designer in constructing the network. Different target procedures, like the pinch analysis, are widely used both inacademia and industry. Another approach to find cost optimal network structures is to use mathematical programming methods. The advantagewith mathematical programming methods is that a rigorous optimization of the structure, sizes of heat exchangers and utility usage can becarried out, whereas the designer makes these decisions if purely pinch-based tools are used.Even if much effort has been put on research within this area, many of the mathematical models consider only grassroot design, whereasmost practical cases today seem to be retrofit situations. In addition, these models are likely to be either rigorous but not solvable for bigger(large-scale, real life examples) or deficient and solvable for large-scale problems. This paper takes an attempt to address these problemssimultaneously and to develop a rigorous optimization framework based on both a genetic algorithm and a deterministic MINLP-approachand to present an extended model for large-scale retrofit heat exchanger network design problems.
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| 10. |
- Boss, Annika, et al.
(författare)
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Uppvärmning och kylning av lokaler ur energi- och miljömässigt samt ekonomiskt perspektiv
- 2009
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Rapport (refereegranskat)abstract
- Demand for cooling of commercial buildings is increasing and there is a potential for expanding district cooling systems, especially in district heating areas. Using district heating and district cooling has been compared to heat pump techniques. Primary energy, environmental influence and economy have been evaluated. Four buildings in Gothenburg have been included in the study and certain differences have been found depending on demands of heating and cooling, which vary according to design and activity. The results are specific for Gothenburg due to the combination of production methods for district heating and cooling and the pricing, which differ compared to other places. Different perspectives on production of electricity, district heating and district cooling, e.g. average or marginal production, is of vital importance when comparing environmental influence. In most of the case studies the demand of primary energy is lower for district heating and cooling compared to heat pump systems. With a marginal perspective district heating and cooling will lead to lower emissions of greenhouse gases. Using the perspective of average production will on the other hand rate heat pump systems to have a lower influence on the greenhouse effect in most of the cases. Which technique is the most cost efficient depends mainly upon relation of heating and cooling demands. Where there is a greater demand for cooling than for heating, district heating and cooling is more advantageous. It is a need for improved data in commercial buildings from reliable field measurements. The quality of the evaluation is very much dependent on reliable measured data from real installations.
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