Experiments on torrefied wood pellet: study by gasification and characterization for waste biomass to energy applications

Rollinson, Andrew; Williams, Orla

Abstract

Samples of torrefied wood pellet produced by low-temperature microwave pyrolysis were tested through a series of experiments relevant to present and near future waste to energy conversion technologies. Operational performance was assessed using a modern small-scale downdraft gasifier. Owing to the pellet's shape and surface hardness, excellent flow characteristics were observed. The torrefied pellet had a high energy density, and although a beneficial property, this highlighted the present inflexibility of downdraft gasifiers in respect of feedstock tolerance due to the inability to contain very high temperatures inside the reactor during operation. Analyses indicated that the torrefaction process had not significantly altered inherent kinetic properties to a great extent; however, both activation energy and pre-exponential factor were slightly higher than virgin biomass from which the pellet was derived. Thermogravimetric analysis-derived reaction kinetics (CO2 gasification), bomb calorimetry, proximate and ultimate analyses, and the Bond Work Index grindability test provided a more comprehensive characterization of the torrefied pellet's suitability as a fuel for gasification and also other combustion applications. It exhibited significant improvements in grindability energy demand and particle size control compared to other non-treated and thermally treated biomass pellets, along with a high calorific value, and excellent resistance to water.

Citation

Rollinson, A., & Williams, O. (2016). Experiments on torrefied wood pellet: study by gasification and characterization for waste biomass to energy applications. Royal Society Open Science, 3, Article 150578. https://doi.org/10.1098/rsos.150578

• Journal Article Type: Article
• Acceptance Date: Apr 26, 2016
• Publication Date: May 25, 2016
• Deposit Date: May 25, 2016
• Publicly Available Date: May 25, 2016
• Journal: Royal Society Open Science
• Electronic ISSN: 2054-5703
• Publisher: The Royal Society
• Peer Reviewed: Peer Reviewed
• Volume: 3
• Article Number: 150578
• DOI: https://doi.org/10.1098/rsos.150578
• Keywords: gasification, biomass, torrefaction,; waste to energy, kinetics, grindability
• Public URL: https://nottingham-repository.worktribe.com/output/788687
• Publisher URL: http://rsos.royalsocietypublishing.org/content/3/5/150578
• Contract Date: May 25, 2016