| 1. |
- Anderson, Johan, 1973-, et al.
(författare)
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Assessment of Self-Heating in Wood Pellets by FE Modelling
- 2017
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Konferensbidrag (refereegranskat)abstract
- The self-heating process in a laboratory scale experiment has been modelled using the Comsol Multiphysics software. In the simulations the gas flow and air movement in the volume and heat diffusion in the bulk were taken into account however only one reaction in the pellets bulk is considered. The input data is found from measurements of the reaction chemistry and the heat transfer properties. It is found that all relevant physics is needed in order to obtain reasonable predictions in particular the heat transfer between the bulk and the gas is important but also condensation and evaporation of moisture.
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| 2. |
- Larsson, Ida, et al.
(författare)
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Assessment of the Self-heating Potential of Wood Pellets
- 2012
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The use of biomass pellets is increasing. As a consequence, large indoor storage facilities are needed along the transportation chain. The increased production volumes, transportation, handling and storage of pellets result in increased risks. A number of fire incidents due to spontaneous ignition in wood pellets have been reported. Increased efforts concerning safety and quality assurance are, therefore, important. The aim of the present work is to provide methods for estimating risks for self-heating from pellets stored in bulk quantities. The experimental work ranges from small-scale characterizations to medium-scale storage tests and includes several different types of pellets. One aim has been to develop small scale screening methods to assess the propensity for self-heating, thereby trying to define the specific type of “activity” occurring in the pellets as well as characterising it. Isothermal calorimetry (micro calorimeter) has been used as small scale screening test method and the results has then been validated with crossing point tests and in medium scale tests (1 m3). Thirteen samples from different types of pellets have been ranked relative to each other in micro calorimeter tests and two pellet types; one “reactive” and one “less reactive” were also tested for validation in crossing point and medium scale. The results clearly reveal that different activity levels of the pellets can be measured using small scale screening methods.
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| 3. |
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| 4. |
- Larsson, Ida, et al.
(författare)
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Small scale screening tests to assess the self-heating potential of wood pellets
- 2013
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Ingår i: Interflam 2013. - London, UK : Interscience Communications. ; , s. 623-628
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The use of biomass pellets is increasing. As a consequence, large indoor storage facilities are needed along the transportation chain. A number of fire incidents due to spontaneous ignition in wood pellets have been reported. The aim of the present work is to provide methods for estimating risks for self-heating from pellets stored in bulk quantities. The experimental work ranges from small-scale characterizations to medium-scale storage tests and includes different types of pellets. One aim has been to develop small scale screening methods to assess the propensity for self-heating, thereby trying to define the specific type of “activity” occurring in the pellets as well as characterising it. Isothermal calorimetry (micro calorimeter) has been used as small scale screening test method and the results has then been validated with crossing point tests and in medium scale tests (1 m3). Thirteen samples from different types of pellets have been ranked relative to each other in micro calorimeter tests and two pellet types; one “reactive” and one “less reactive” were also tested for validation in crossing point and medium scale. The results clearly reveal that different activity levels of the pellets can be measured using small scale screening methods.
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| 5. |
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| 6. |
- Larsson, Ida, et al.
(författare)
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Temperature Measurements and Examination of Self-heating in Large Scale storage of Wood Pellets
- 2014
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Ingår i: World Bioenergy 2014. - Jönköping, Sweden.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper summarizes the experimental data from a large-scale storage test performed within the European project called SafePellets. Temperature measurements were made inside a silo with a capacity of storing 3000 ton of wood pellets, from August to October in 2013. The purpose of the test was to examine the self-heating of the wood pellets, where and when it occurs, how it spreads and if it could be connected to certain events. For temperature measurements, both the temperature cables belonging to the silo temperature surveillance system and thermocouples mounted by SP at the cables and on the in/out-side walls of the silo were used. The results clearly reveal that self-heating occurs almost instantly after start of filling the silo and temperatures above 40 °C inside the pellets bulk is regular. The temperature surveillance system, which was set to give an alarm signal for high temperatures, was activated several times during the test period and temperatures exceeding 60 °C were registered at several occasions. Measurements above the pellet surface also show that this headspace temperature varies much with the outside ambient temperature and the sunlight radiation. A sunny summer’s day, the headspace temperature could easily reach above 40 °C, which will influence the pellet bulk. The project also emphasized an important problem when it comes to silo storage. The problem of temperature sensor cables inside the silo not always hanging where they are supposed to be was observed in the test and dealt with.
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| 7. |
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| 8. |
- Lönnermark, Anders, 1968-, et al.
(författare)
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Self-heating and Off-gassing from Biomass Pellets during Storage
- 2012
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The use of biomass pellets is increasing. As a consequence,large indoor storage facilities are needed along the transportation line. Theincreased production volumes, transportation, handling and storage of pellets resultin increased risks. A number of fire incidents due to spontaneous ignition inwood pellets storages and accidents due to CO intoxication have been reported.Increased efforts concerning safety and quality assurance are, therefore,important. The aim of the present work is to provide methods for estimatingrisks for self-heating of and off-gassing from pellets stored in bulk. Theexperimental work ranges from small-scale characterizations to large-scalestorage tests and includes several different types of pellets. One aim has been to develop smallscale screening methods to assess the propensity for self-heating andoff-gassing, thereby trying to define the specific type of “activity” occurringin the pellets as well as characterising it. In addition to using said methods,isothermal calorimetry (micro calorimeter) and Oxipres (oxygen depletion), theformation of different gases (e.g. aldehydes) was analyzed. Thirteen samples from different types of pellets havebeen ranked relative to each other. Effects of processes like aging can also beseen in the results. The results clearly reveal that different activity levelsof the pellets can be measured using small scale screening methods and thatthere are certain correlations between off-gassing and heat development, althoughthese are not yet fully understood.
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| 9. |
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