Wood Torrefaction Utilizing Rotary CalcinerDr. Donald Fosnacht, director of the NRRI Center for Research and Technology Development, will present "Manufacture of Moisture Resistant Torrified Biomass Agglomerates" at the International Biomass Conference on March 26. The paper is part of a panel discussion on "Drop-in Biomass: Using Torrefaction to Produce a Fuel that More Seamlessly Integrates with Coal Combustion Infrastructure."

During the presentation, Dr. Fosnacht describe an upcoming torrefaction project at NRRI's Coleraine, Minn.-based facility that is the result of six years of research involving a Heyl & Patterson torrefaction unit and other components. The project is expected to produce approximately 28,800 lb of biocoal per day. According to Heyl & Patterson, the project will focus on the cost and thermal effectiveness of the value-added conversion of wood biomass into biocoal.

In the process, low moisture wood chips enter the torrefaction unit — also called a rotary calciner — and indirect heat is applied to roast the wood without burning it. This produces torrified wood chips that then can be pelletized for commercial and residential use. The heat and gases that are generated can also be returned to the unit to lessen the amount of new energy needed to generate heat, or redirected to help heat a rotary dryer, which can be used to dry more wood chips that, in turn, are fed into the calciner. In addition to its uses as a coal additive, torrefied wood also can be used as activated carbon for filtration and purification applications.

To learn more about torrefaction, download a white paper from Heyl & Patterson.