Changes in the mechanical properties of biomass wood pellets during artificial degradation in a laboratory environment

Graham, Shalini L.; Ogunfayo, Ibrahim; Hall, Matthew R.; Snape, Colin; Quick, Will; Weatherstone, Susan; Eastwick, Carol

Abstract

In stockpiles exposed to high relative humidity (RH) and rainfall, woody biomass pellets lose structural integrity, often assumed to be due to the uptake of moisture from the environment. In this study three different types of biomass pellet were artificially degraded in a laboratory environment under controlled exposure to RH (10% and 90% RH ) and temperature (range of 10 to 30°C). White, torrefied and steam-exploded wood pellets were investigated. Daily shear tests were conducted with durability and moisture content measured. The exposure of all three pellet types to high RH coupled with elevated temperatures caused a substantial decrease of shear modulus with values of 50% to 92% decrease compared to fresh pellets after 4 days exposure. The steam exploded pellets saw the lowest drop in mechanical durability (5%) but saw the largest decrease in shear modulus, whilst the white wood pellets disintegrated in situ after 4 days. In contrast storage at 10% RH did not cause any observable degradation, with mechanical behaviour of steam exploded and torrefied pellets showing an improvement. This paper presents both testing methodology as well as clear indication of the behaviour of three woody biomass pellets on exposure to high relative humidity.

Citation

Graham, S. L., Ogunfayo, I., Hall, M. R., Snape, C., Quick, W., Weatherstone, S., & Eastwick, C. (2016). Changes in the mechanical properties of biomass wood pellets during artificial degradation in a laboratory environment. Fuel Processing Technology, https://doi.org/10.1016/j.fuproc.2016.03.020

• Journal Article Type: Article
• Acceptance Date: Mar 18, 2016
• Online Publication Date: Apr 8, 2016
• Publication Date: Jul 1, 2016
• Deposit Date: Apr 20, 2016
• Publicly Available Date: Apr 20, 2016
• Journal: Fuel Processing Technology
• Print ISSN: 0378-3820
• Electronic ISSN: 0378-3820
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1016/j.fuproc.2016.03.020
• Keywords: wood; pellet; storage; degradation; torrefied; steam exploded; biomass; fuel; power plant
• Public URL: https://nottingham-repository.worktribe.com/output/792015
• Publisher URL: http://www.sciencedirect.com/science/article/pii/S0378382016301217
• Related Public URLs: http://www.sciencedirect.com/science/article/pii/S0378382016301217