Abstract
The physical and combustion properties of roller-milled and hammer-milled wood pellets for suspension-firing are characterized both experimentally and numerically. The particle size and shape distribution is measured based on dynamical digital image processing. The traditional coal roller mills produce larger biomass particles than hammer mills do. The true density of the particles, measured by ethanol displacement method, does not remarkably vary with the different mills. Combustion tests of the milled biomass particles are performed in a single particle combustion reactor under conditions close to suspension-fired boilers. The ignition, devolatilization and burnout times of the milled particles under different combustion conditions are analysed. A one-dimensional transient model, properly accounting for the particle-ambient flow interaction and appropriately addressing the key sub-processes within the particle, is also developed to predict the combustion behaviours. The good agreement between the model predictions and the experimental results serves as a cross validation of both the tests and the model. Without changes in the infrastructure, biomass pelletizing may not be a viable pre-treatment for large-scale biomass combustion in the existing pulverized coal-fired utility boilers.
Original language | English |
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Title of host publication | Proceedings of 9th International Conference on Multiphase Flow, May 22-27, 2016, Firenze, Italy |
Number of pages | 5 |
Publisher | International Conference on Multiphase Flow |
Publication date | May 2016 |
Publication status | Published - May 2016 |
Event | The 9th International Conference on Multiphase Flow - Firenze, Italy Duration: 22 May 2016 → 27 May 2016 http://www.aidic.it/icmf2016/ |
Conference
Conference | The 9th International Conference on Multiphase Flow |
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Country/Territory | Italy |
City | Firenze |
Period | 22/05/2016 → 27/05/2016 |
Internet address |
Keywords
- Biomass pellet
- Suspension combustion
- Roller mill
- Hammer mill
- Pulverized fuel boiler