| 1. |
- Anderson, Johan, 1973-, et al.
(författare)
-
Assessment of Self-Heating in Wood Pellets by FE Modelling
- 2017
-
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.
|
|
| 2. |
|
|
| 3. |
- Koppejan, Japp, et al.
(författare)
-
Health and safety Aspects of Solid Biomass Storage, Transportation and Feeding
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This publication focuses on the health and safety issues of the supply chain of solid biofuels with the objective to highlight commonly used mitigation methodologies to promote a better working environment when dealing with solid biofuels. It has been compiled as a joint effort by experts active in Tasks 32, 36, 37 and 40 of the IEA Bioenergy Agreement, with their own specific fields of expertise. Only through this cooperation, it was possible to touch upon the full range of issues in one publication that one may come across when developing projects in which solid biomass fuels are produced, traded or used. The properties of a biomass material and the intended use determine how the material should be safely transported and stored. Self-heating, off-gassing and dust explosions are significant challenges for the industry that have already resulted in significant losses of capital investments and even tragic loss of life. Likewise, exposure to biologically active material, such as moulds and spores may form a serious hazard for the health of workers involved. With the growth of the bioenergy sector, it is important not only that opportunities for bioenergy are implemented in an efficient economic manner, but also safely.
|
|
| 4. |
|
|
| 5. |
- Larsson, Ida, et al.
(författare)
-
Assessment of the Self-heating Potential of Wood Pellets
- 2012
-
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.
|
|
| 6. |
|
|
| 7. |
- Larsson, Ida, 1978-, et al.
(författare)
-
Development of a screening test based on isothermal calorimetry for determination of self-heating potential of biomass pellets
- 2017
-
Ingår i: Fire and Materials. - : John Wiley & Sons. - 0308-0501 .- 1099-1018. ; 41:8, s. 940-952
-
Tidskriftsartikel (refereegranskat)abstract
- For the risk for spontaneous combustion in storage of biomass pellets to be assessed, it is important to know how prone the fuel is to self-heating. There are traditional methods that are used to determine self-heating characteristics of fuels, eg, basket heating tests. The results from basket heating tests indirectly give the reactivity from a series of tests at high temperatures. This paper presents a sensitive screening test procedure for biomass pellets using isothermal calorimetry for direct measurement of the heat production rate at typical bulk storage temperatures. This method can be used to directly compare the reactivity of different batches of biomass pellets. The results could be used, eg, by storage security managers to gain better knowledge of their fuels propensity for self-heating and thereby for safer storage. A large number of tests have been performed to develop the test procedure presented. Different parameters, such as temperature, type of the test sample (powder/crushed or pellets), mass of test sample, and preheating time, have been varied. Furthermore, gas concentrations in the sample ampoule have been measured before and after some tests to study the oxygen consumption and the formation of CO and CO2. Three different types of pellets with different characteristics were tested to assess the variation in behaviour. Based on these tests, a screening test procedure is presented with a test temperature of 60°C, a sample size of 4 g, a 15-minute preheating period at the test temperature, and 24-hour test duration.
|
|
| 8. |
- Larsson, Ida, et al.
(författare)
-
Measurement of self‐heating potential of biomass pellets with isothermal calorimetry
- 2017
-
Ingår i: Fire and Materials. - : John Wiley & Sons. - 0308-0501 .- 1099-1018. ; 41:8, s. 1007-1015
-
Tidskriftsartikel (refereegranskat)abstract
- In order to assess the risk for spontaneous combustion of biomass pellets during storage it is important to know how prone the fuel is to self-heating, i.e. to determine the reactivity. This article presents the results from isothermal calorimetry tests performed on 31 different biomass pellet batches. The purpose of the tests has been to characterize pellets by measuring the reactivity and investigate how the pellet composition influences the heat release rate and thereby the self-heating potential of pellets. The results from the tests clearly indicate that there is a significant difference in reactivity between different types of pellets. The tested high reactive pellet batches reached maximum specific heat release rates (HRRmax) of 0.61-1.06 mW/g while pellet batches with low reactivity showed HRRmax of 0.05-0.18 mW/g. The tested batches were primarily ranked based on HRRmax but an alternative ranking based on specific total heat release rate during the test period was also used for comparison. The test results also indicate that pine/spruce mix pellets are significantly more reactive than all other types of pellets tested and that pellets consisting of 100 % pine are more reactive than pellets consisting of 100 % spruce. Pellets produced from wine pruning/grape pomace (winery wastes), straw or eucalyptus are not very reactive compared to pellets consisting of pine/spruce. The results also show that the reactivity of the pellets can be reduced by either introducing certain kinds of anti-oxidants into the pellets or by extracting lipids from the raw material of pellets.
|
|
| 9. |
- Larsson, Ida, et al.
(författare)
-
Medium-scale reference tests and calculations of spontaneous ignition in wood pellets - the LUBA project
- 2012
-
Rapport (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 present work is to provide methods for estimating risks for self-heating from pellets stored in bulk quantities. This report compares medium scale tests of pellets in bulk with smaller screening test; micro calorimeter and crossing point. Two types of pellets; one “reactive” and one “less reactive” were compared. Kinetic parameters from the crossing point and micro calorimeter tests was used as input data for Frank-Kamenetskii calculations and compared with the medium scale test results. Calculations of the critical ambient temperature and time to self-ignition have also been preformed on four different types of representative types of full scale storages that either exist today or might be possible in the future. The results clearly reveal that results in medium scale can be predicted by using results from small scale screening methods like isothermal calorimetry or crossing point. The small scale test methods show the same indications as medium scale when comparing reactive and less active pellet types. The medium-scale tests were effective in separating the self-heating activity of the two types of pellets investigated.
|
|
| 10. |
|
|
