A Review of Pellets from Different Sources

Area of Science:

• Biomass energy
• Materials science
• Waste valorization

Background:

• Growing pellet consumption drives demand for diverse raw materials, including agricultural and forestry wastes.
• The EN ISO 17225 standard governs biomass pellet quality for industrial and household use.
• Increased availability of waste materials suitable for biomass conversion necessitates quality assessment.

Purpose of the Study:

• To analyze the characteristics of laboratory-made pellets from ten different raw materials.
• To identify key quality factors limiting the market suitability of these pellets according to EN ISO 17225.
• To assess the potential of densified wastes for higher-value biomass markets.

Main Methods:

• Preparation of ten distinct types of laboratory-made pellets.
• Analysis of pellet characteristics, focusing on parameters critical to EN ISO 17225.
• Comparison of analyzed pellet properties against established quality standard limits.

Main Results:

• Significant variations in pellet quality were observed across the different raw material types.
• Nearly all analyzed pellets exceeded the EN ISO 17225 standard limits for several parameters.
• Ash content, nitrogen (N), and sulfur (S) composition were particularly problematic, frequently exceeding acceptable thresholds.

Conclusions:

• The stringent requirements of the EN ISO 17225 standard hinder the market entry of many densified waste materials.
• Current waste-derived pellets often fail to meet quality benchmarks, restricting their use in higher-value applications.
• Further research and potential standard adjustments may be needed to facilitate the broader utilization of biomass waste pellets.