The optimised pellet and briquette - a systems study looking forward

Use of processed biofuels (pellets, briquettes) has greatly increased in Sweden in recent decades, mainly to replace fossil fuels in large boilers, e.g. in coal powder boilers. More recently, the demand from private households and residential heating systems has also increased, mainly due to conversion from fossil heating oil. This increased interest in pellets and briquettes for heating is beginning to cause a shortage of the traditional raw materials, sawdust and wood shavings, and therefore attention is turning to using a variety of agricultural products as raw material. Such raw materials include cultivated energy crops and wastes and by-products from agriculture.

The objectives of this study were to:

• Describe typical systems currently used for production of pellets and briquettes
• Investigate the possibility of using energy crops (Salix, reed canary-grass and hemp) and various wastes and by-products from processing of farm products (straw, cereal screenings, rapeseed meal and distiller’s waste) as raw materials
• Investigate previous experiences of pelleting and briquetting of these raw materials
• Comprehensively identify possible combustion problems that may occur
• Suggest scenarios for possible production systems in a five-year perspective and calculate the costs and energy demands for these systems.

These future scenarios included large-scale plants and micro-scale plants, as well as static and mobile equipment.

Publications:

Nilsson, D., Bernesson, S. 2008. Pelletering och brikettering av jordbruksråvaror - En systemstudie. Processing biofuels from farm raw materials - A systems study. SLU, Institutionen för energi och teknik, Rapport 001, Uppsala.