Drying is a major and challenging step in the pre-treatment of biomass for production of second generation synfuels for transport. The biomass feedstocks are mostly wet and need to be dried from 30 to 60 wt% moisture content to about 10-15 wt%. The present survey aims to define and evaluate a few of the most promising optimised concepts for biomass pre-treatment scheme in the production of second generation synfuels for transport. The most promising commercially available drying processes were reviewed, focusing on the applications, operational factors and emissions of dryers. The most common dryers applied now for biomass in bio-energy plants are direct rotary dryers, but the use of steam drying techniques is increasing. Steam drying systems enable the integration of the dryer to existing energy sources. In addition to integration, emissions and fire or explosion risks have to be considered when selecting a dryer for the plant. In steam drying there will be no gaseous emissions, but the aqueous effluents need often treatment. Concepts for biomass pre-treatment were defined for two different cases including a large-scale wood-based gasification synfuel production and a small-scale pyrolysis process based on wood chips and miscanthus bundles. For the first case a pneumatic conveying steam dryer was suggested. In the second case the flue gas will be used as drying medium in a direct or indirect rotary dryer. (C) 2010 Elsevier Ltd. All rights reserved.

Bio-oil (biomass fast pyrolysis) systems for heat, power or CHP production are nearing demonstration status. Their commercial attractiveness will depend on many factors, and will vary with the application, the scale, and importantly the location and its associated economic and logistical factors. The objective of this work, carried out as part of an EC-ALTENER project, was to evaluate the opportunities for bio-oil in the heat and power markets of Europe. Bio-oil applications were compared with conventional (fossil) alternatives for the same heat and power duty. The evaluation was carried out by a quantitative assessment of the economic competitiveness of standard applications in 14 European countries. Location-specific data were collected, and combined with technology-specific data obtained from earlier work. A competitiveness factor (cF) was derived which represents the total annual cost of a conventional alternative relative to a bio-oil application. The results showed a wide variation across Europe. A total of six countries had at least one bio-oil application which was economically competitive. Heat-only applications were found to be the most economically competitive, followed by CHP applications, with electricity-only applications only very rarely competitive. For a given technology, the larger the scale, the better the competitiveness.