Biomass gasification and more precisely Biomass to Liquids (BtL)
plants have been described in a large number of publications
together with estimations for investment and fuel production costs
[1,2]. The various BtL plants that are currently being designed are
mostly demonstration projects to test and validate the technology
chain. Commercial BtL plants are not yet in operation, all studies
presenting production economics should be considered prospective.
The predicted cost of biofuels is higher than fossil fuels [2] and
economies of scale are difficult to realise. The competitiveness of
BtL plants should, at least partly, come from technology
improvements.
The BtL process is built up from a large number of steps as
described by Refs. [2], these include drying, grinding, gasification
and fuel synthesis. After gasification, the synthesis gas is made up
to specification in the water gas shift section and in the purification
section. The fuel synthesis section produces the desired final
product (diesel, gasoline, methanol or others). In this paper we
concentrate on the biomass dryer and the water gas shift section.
Forced biomass drying is deemed unavoidable in most BtL
plants designs. Drying of woodchips is slow and generally