This paper examines thermochemical biomass conversion plants that produce synthesis gas that can be
converted into synthetic fuels. Biomass requires forced drying before torrefaction or gasification to increase
the heating value of the feed, an energy consuming step that weighs heavy in the energy balance
of the plant. This paper shows that decreasing the humidity of the admitted drying air greatly improves
the efficiency of the biomass drying. It is possible to reduce the humidity of the air by passing the air on a
water adsorbent solid such as activated alumina. The alumina loaded with water can then be regenerated
with waste heat, but more efficiently by using synthesis gas and convert the adsorbed water to hydrogen
in the water gas shift section. The energy saved in the improved drying step amounts to 2e8% of the total
fuel consumption of the plant, depending on the ambient conditions.