Torrefaction is a promising biomass upgrading method, offering advantages in logistics and handling. Gasification is an attractive thermochemical conversion technology due to its flexibility in the product gas end-use. The aim of this paper is to investigate the impact of torrefaction on the gasification performance of a softwood (spruce) and a hardwood (ash). Spruce and ash were torrefied at 260 and 280 °C, and at 250 and 265 °C, respectively, and pelletized. All feedstocks were gasified at 850 °C and atmospheric pressure under oxygen-steam circulating fluidized bed gasification conditions, with magnesite as bed material and with an equivalence ratio (ER) of 0.3 and a steam-to-biomass mass ratio (SBR) of 1.0. Only the torrefied feedstocks were gasified varying ER and SBR values. The results show that torrefaction affected the gasification performance of both feedstocks leading to decreasing the cold gas and carbon conversion efficiencies. For spruce, torrefaction did not affect the permanent gas composition but led to a decrease of the total tar content for both spruce 260 and spruce 280. For ash, torrefaction resulted in decreasing the CH4 volume fraction, and increasing the H2 volume fraction and the total tar content for both torrefaction temperatures. Varying the ER and SBR affected only the Class 3 tars of ash 250. Conclusively, torrefaction of spruce and ash did not offer substantial benefits on the gasification performance under the investigated conditions. It is suggested that research of torrefied wood gasification includes feedstock's chemical analysis and characterization of products obtained under fast devolatilization conditions.@en

Torrefaction is a promising biomass upgrading technology as it makes biomass more coal alike and offers benefits in logistics and handling operations. Gasification is an attractive thermochemical conversion technology due to its flexibility in the product gas end-uses. Therefore, it is valuable to investigate whether additional benefits are foreseen when torrefaction is coupled with gasification. Therefore, two commercial torrefied wood fuels and their parent materials are gasified at 800–850 °C under atmospheric steam-oxygen circulating fluidized bed gasification conditions and magnesite as bed material. The torrefied feedstocks consisted of wood residues torrefied by Topell at 250 °C (Topell black), and mixed wood and wood residues torrefied by Torrcoal at 300 °C (Torrcoal black). The gasification results show that torrefaction resulted in an increased gas quality, as it yielded higher H2 and CO contents, a decrease of the CO2 content, increased gas yield and a significant decrease of the total tar content for both feedstocks. For the Torrcoal samples, torrefaction resulted in a decrease in the carbon conversion efficiency (CCE). In addition, the cold gas efficiency (CGE) remained approximately the same due to the increase in the H2 and CO contents. The Topell samples showed an increase in the CCE and CGE upon torrefaction, but this could be attributed to a significant grinding in the screw feeder. It is generally concluded that both torrefied fuels may offer benefits as a feedstock for steam-oxygen blown circulating fluidized bed gasification, in particular in terms of gas quality and yield.@en

This study evaluates whether a transition of large ports facilities to biofuel production for mobility improves the environmental performance and satisfies the renewable energy directive (RED) and it is the first LCA study that considers biofuel production from torrefied wood. The systems studied are wood, torrefied wood, and straw pellets circulating fluidized bed gasification for H2, synthetic natural gas, or Fischer–Tropsch (FT) diesel production and use. These systems are evaluated for their global warming, acidification, eutrophication and particulate matter potentials, as well as, for their aggregated environmental performance. The effects of the electricity mix selection and ecoinvent database’s economic allocation are also analyzed. All biomass systems result in a better aggregated environmental performance and benefits for the global warming potential. However, regarding the acidification, particulate matter, and eutrophication potentials, most biomass systems are inferior to the reference systems. Switching to a zero-emission electricity mix offers benefits for all the biomass and fossil-H2 systems and researchers should use databases cautiously. The bio-H2 and FT diesel of wood-based systems show the best environmental performance and satisfy the current and future RED targets. On one hand, the bio-H2 systems result in the largest benefits regarding the global warming potential, and on the other hand, both wood-based FT diesel systems offer overall benefits which concern not only the sustainable target of CO2 emissions reduction, but also the air quality improvement of the broader area as well.@en