Biofuels in Perspective

106 Biofuels
Figure 6.5 Schematic line-up of the optimum syngas/FT biodiesel production process. Reproduced by
permission of ECN.
6.3.4 Biomass Feeding and Pre-treatment
Biomass is different from coal in many respects; the most relevant relates to feeding.
Biomass requires significant pre-treatment to allow stable feeding into the gasifier without
excessive inert gas consumption. In addition to the requirement to pre-treat the biomass
for feeding, it may also be desired for purpose of densification of the material. Due to the
smaller volume transport costs are reduced and the stability of the gasifier operation is
increased, due to the higher energy density of the feed.
The development of new approaches to biomass feeding and pre-treatment is necessary to
reach high biomass-to-biosyngas and overall system efficiencies in biomass-fired entrained
flow gasifier systems.
In Figure 6.6 four possible specific pre-treatment and feeding options are shown for
different biomass streams. A fifth feeding option, not presented in this figure, is feeding a
residual product, e.g. black liquor from pulp and paper industry, and hence integrate the
Figure 6.6 Different biomass pre-treatment and feeding option. Reproduced by permission of ECN.