Biofuel and green chemicals created from close-to-source agroforest residue
Existing forestry resources in Europe are insufficient to meet the demands of the bioenergy market. However, there are abundant unexploited biomass resources across Europe that are not yet in a form that can be readily collated and used by a large-scale bioeconomy. There is an urgent need to cost effectively collate and present this biomass in an efficiently usable and transportable form. The EU-funded Horizon 2020 project SteamBio addressed this challenge by developing a mobile processing concept for the efficient pre-treatment of agroforestry residues. The goal is their use as feedstock in chemical and process industries. Better fuel properties Project partners used superheated steam processing (SHS) as the core technology. Utilised in diverse drying applications at the industrial scale, SHS has superior heat transfer properties. “It has been proven at pilot scales to torrefy assorted biomass materials into hydrophobic and grindable solids with value-added volatile compounds as a sidestream,” says project coordinator Siegfried Egner. “The continuous SHS processing technology platform in SteamBio is scalable and has been proven technically at industrial scales with temperatures up to 300 C.” Torrefaction changes the properties of lignocellulose material e.g. agricultural and forestry residue, to provide a better fuel quality for combustion and gasification applications. It is a thermal process that converts biomass into a coal-like material, which has better fuel characteristics than the original biomass. This includes brittleness, making grinding easier and less energy intensive. Furthermore, torrefaction produces a dry product with no biological activity such as rotting. “The efficiency of our process is based on working in a controlled atmosphere of steam, which is generated from the moisture in the materials and therefore inert due to absence of oxygen,” Egner explains. The project overcomes many of the limitations found in existing torrefaction processes to enable maximum value recovery and minimal environmental impacts. “Unlike conventional torrefaction techniques, which employ flue gases as a heating medium, SteamBio does not contaminate the torrefied biomass and volatile fractions, enabling the economic recovery of chemicals. Moreover, it is also readily scalable for continuous operation,” claims Egner. Useful biochemicals Researchers also deployed a demonstration unit with a throughput of 150 kg/hr in different rural locations. According to Egner: “Recovered condensate from the superheated steam process has already been shown to contain commercially relevant quantities of biochemicals in addition to the torrefied biocarbon mass that can be used as a biofuel and in biochemicals.” The torrefied biomass fractions (solid and liberated volatiles) will be validated as green building blocks in commercially relevant chemical production and in bioenergy use. Life cycle experts will also confirm the project’s positive environmental impacts. SteamBio will help create local jobs, generating wealth in the local economy as well as making a significant contribution to the sustainability of supply chains for energy and chemicals. “The project benefits the agriculture industry by valorising waste streams, the chemical industry by giving platform chemicals, and energy providers by supplying highly efficient feedstock for burning,” Egner concludes.
Keywords
SteamBio, biomass, superheated steam processing (SHS), torrefaction, biofuel
