Raw Material Supply and its Influence on Profitability and Life-Cycle Assessment of Torrefied Pellet Production in Finland – Experiences from Pilot-Scale Production
Föhr, Jarno (2021-11-05)
Väitöskirja
Föhr, Jarno
05.11.2021
Lappeenranta-Lahti University of Technology LUT
Acta Universitatis Lappeenrantaensis
School of Energy Systems
School of Energy Systems, Energiatekniikka
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Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-335-726-6
https://urn.fi/URN:ISBN:978-952-335-726-6
Tiivistelmä
The European climate policy aims to move toward an environmentally friendly world, and it has been awakened by a strong will to find replacement fuel alternatives to fossil fuels, especially for coal. Torrefied pellets have emerged as a noteworthy alternative because their properties are more similar to coal. Because of this, it can be used in large quantities for co-combustion in coal-fired boilers. In this case, existing coal boilers do not need to be replaced by the new boilers. However, there have been problems with moving the technology of torrefaction forward and this dissertation has wanted to address this.
The purpose of this dissertation was to investigate the process technology and production costs of torrefied pellets, and the emissions of the supply chain in terms of research. The other purpose was to investigate the raw material differences in terms of heating value and to determine their effects on the profitability of a theoretical large-scale bio-coal pellet plant, and therefore on the production economy. The research environment was the region of South Savo, in Finland. At first, the focus of the studies was on the test runs in the pilot plant and base data for the dissertation was produced on these tests. At a later stage, the studies were expanded to the theoretical examinations dealing with the largescale bio-coal pellet plant, and greenhouse gas emissions of the torrefied pellet supply chain.
The dissertation achieved the stated research objectives and provided accurate research information on the material properties of manufactured torrefied pellets. The work also achieved results on the costs of manufacturing the torrefied pellets and the cost of the entire supply chain. The total supply cost was €31.03–33.12/MWh for all pellet types in the large-scale plant. In addition, the work achieved economic calculations for the regional economy and determined the selling prices for the pellets. The highest final price (€37.02–42.92/MWh) was obtained for spruce pellets, but it caused the lowest annual economic impact for the region (€35.41–41.05 million). Finally, this work clarified the potential for reducing GHG emissions from the torrefied pellet supply chain. The GHG emissions were estimated by using a life cycle assessment. The reduction potential occurred in different sections of life cycle phases like using different chipping or crushing methods, using alternative supply chain paths, or using different materials like larger stems.
Based on the studies of this dissertation, more research is needed to explore differences in heating value between wood materials and the resulting economic impact. The supplementary research is also needed on the emission footprint of torrefied pellets over their entire life cycle. In addition, more research is needed for the technology aspect of the torrefaction and especially for solution based on a vertical reactor. This way ensures a smooth passage from the pilot phase to the launch of the continuously operated plant.
The purpose of this dissertation was to investigate the process technology and production costs of torrefied pellets, and the emissions of the supply chain in terms of research. The other purpose was to investigate the raw material differences in terms of heating value and to determine their effects on the profitability of a theoretical large-scale bio-coal pellet plant, and therefore on the production economy. The research environment was the region of South Savo, in Finland. At first, the focus of the studies was on the test runs in the pilot plant and base data for the dissertation was produced on these tests. At a later stage, the studies were expanded to the theoretical examinations dealing with the largescale bio-coal pellet plant, and greenhouse gas emissions of the torrefied pellet supply chain.
The dissertation achieved the stated research objectives and provided accurate research information on the material properties of manufactured torrefied pellets. The work also achieved results on the costs of manufacturing the torrefied pellets and the cost of the entire supply chain. The total supply cost was €31.03–33.12/MWh for all pellet types in the large-scale plant. In addition, the work achieved economic calculations for the regional economy and determined the selling prices for the pellets. The highest final price (€37.02–42.92/MWh) was obtained for spruce pellets, but it caused the lowest annual economic impact for the region (€35.41–41.05 million). Finally, this work clarified the potential for reducing GHG emissions from the torrefied pellet supply chain. The GHG emissions were estimated by using a life cycle assessment. The reduction potential occurred in different sections of life cycle phases like using different chipping or crushing methods, using alternative supply chain paths, or using different materials like larger stems.
Based on the studies of this dissertation, more research is needed to explore differences in heating value between wood materials and the resulting economic impact. The supplementary research is also needed on the emission footprint of torrefied pellets over their entire life cycle. In addition, more research is needed for the technology aspect of the torrefaction and especially for solution based on a vertical reactor. This way ensures a smooth passage from the pilot phase to the launch of the continuously operated plant.
Kokoelmat
- Väitöskirjat [1099]