Preliminary findings for the production of water repellent torrefied wood pellets with pyrolysis oil



Torrefaction of biomass has attracted considerable attention as a means to reduce biomass weight by 70% through removal of water and the hemicellulosic fractions while retaining most of the original high-energy cellulose and lignin content. Current torrefied wood pellets or briquettes cannot be shipped in open containers exposed to precipitation because they are not highly water resistant. A highly water repellent pelletized product is required to allow bulk shipping of torrefied wood pellets or briquettes via open railcar or by barge. We have recently developed a binder produced from biomass components that imparts the water repellent quality required to produce a torrefied product that is able to be shipped in open containers. Crushing strength of the pellets produced with this binder are high at between approximately 700 and 1100 psi. Water repellency tests indicate that upon total immersion the pellets absorb water into available pores up to 2–5%. The pellets can then be dried without unacceptable loss of strength. © 2012 American Institute of Chemical Engineers Environ Prog, 2012