Experimental investigation on biomass shrinking and swelling behaviour: Particles pyrolysis and wood logs combustion

Gianluca Caposciutti, Hernán Almuina-Villar, Alba Dieguez-Alonso, Thomas Gruber, Joachim Kelz, Umberto Desideri, Christoph Hochenauer, Robert Scharler, Andres Anca-Couce

Research output: Contribution to journalArticlepeer-review


Biomass is a suitable energy source to reduce the carbon footprint and increase the use of renewable energy. However, the biomass exploitation is still slowed by many technical issues. In most practical applications, such as gasification or combustion devices, it is important to predict the fuel physical behavior in order to determine the emissions and heat release profile as well as for modeling and design purposes. Within this paper, the study of the dimensional evolution of a biomass fuel (beech wood) in pyrolysis and combustion processes were carried out with the use of the image analysis tool. Sizes from 15 mm to 300 mm characteristic length range were employed in the experiments and the collected data were related to the mass loss and temperature evolution of the biomass particle. It was found that for all the fuel sizes employed a similar volume reduction (60%–66%) was obtained at the end of pyrolysis. However, for the small particles with minor intra-particle gradients shrinkage took place mainly at the end of conversion, while for bigger particles the size variation patter was more linear. Furthermore, swelling was detected in the pyrolysis experiments, and it was higher for a bigger particle size, while cracking and fragmentation phenomena was observed for large wood logs combustion in the stove.

Original languageEnglish
Pages (from-to)1-13
Number of pages13
JournalBiomass & Bioenergy
Issue numberApril 2019
Publication statusPublished - 2019


  • Biomass
  • Image analysis
  • Particle shrinking/swelling
  • Thermochemical conversion

ASJC Scopus subject areas

  • Forestry
  • Waste Management and Disposal
  • Agronomy and Crop Science
  • Renewable Energy, Sustainability and the Environment

Cite this