Analyse des Einflusses von Feinanteil und Feuchtigkeit auf Förderung und Lagerung in Holzpellets in häuslichen Lagerstätten

Project Title
Influence of moisture and fine particles on the conveying and storage stability of wood pellets
Funding Code
62402/005-04#565 - 20565 N / 2 - N08586/18
Principal Investigator
Project Abstract
Constantly rising prices for heating oil and natural gas in households and the environmental impact lead to a rising interest in renewable raw materials. Wood pellets are small cylindrical compacts from natural wood, primarily from sawdust and wood shavings. They are used as a versatile biofuel with a lower emission of the climate-relevant carbon dioxide. These pellets can be burned using a variety of technologies, such as home heating stoves or institutional boiler systems. It is therefore important to look on the overall risks involved in handling these pellets. Mechanical forces during transportation cause fractures and breakage of pellets, resulting in fines and dust. A high content of fine particles can block the conveyor systems. In addition to the fine content, increased moisture due to storage under conditions with high humidity can also lead to a reduction in quality, e.g. by decreasing the flowability of the wood pellets and thus their ability to be conveyed.

The aim of this research is to investigate the formation of fines and dust as well as the influence on the flow behavior of wood pellets during the entire storage and drain process. In addition, the influence of the pellets’ moisture content on their mechanical stability will be quantified. Therefore, the relevant material parameters (e.g. Young’s modulus, coefficient of restitution) will be determined after storage under defined temperature and humidity conditions. The obtained correlations will then be used to simulate the storage and transport as well as local segregation, moisture migration into the bulk and the diffusive moisture transport. The findings from the numerical investigations will be validated by experimental investigations with a lab-scale silo.