ABSTRACT
Only about 7% of total global energy demands are met by industrial processes for renewable energy conversion. If traditional and small-scale usage of renewables (mostly biomass) is included, this figure rises to about 16% (REN21, 2011). Industrial consumption of bioenergy has increased substantially over the last few decades, and is still increasing. Solid biomass is often densified to produce more uniform and standardized bioenergy commodities such as pellets or briquettes, and a variety of systems for achieving such densification have been developed. The most established of these are pellet presses, briquette presses, cuber presses and screw extruders. In addition, there are some newer systems that are still under development, such as the roller press, the tablet press and agglomerator techniques. This area has been reviewed by Tumuluru et al. (2011) and Stelte et al. (2012). The most widely used technique at present is pelleting in rotating die presses, see Figure 13.1. The market for pellets is much larger than that for briquettes and a book has recently been published describing their production and use (Obernberger and Thek, 2010).
