Degree Type


Date of Award


Degree Name

Master of Science


Agricultural and Biosystems Engineering

First Advisor

Matthew J Darr


The main objective for this thesis was to develop a self selection torrefaction system based on an integrated torrefaction and ball milling reactor system. A lab scale torrefaction system has been developed in order to heat biomass material to a temperature of 260-280°C in an inert environment. This process of torrefaction, or mild pyrolysis, is used to break down hemicellulosic biomass in order to produce a material with increased brittleness, hydrophobicity, and resistance to microbial degradation. A limitation of this process is achieving a uniform degree of torrefaction. Heat transfer is reduced as the particle size increases in diameter. The self selection process seeks to remove torrefied material from non-torrefied material in order to improve material uniformity. The ball milling action will separate the biomass based upon degree of torrefaction.

Ball milling of separate raw corn stover and torrefied corn stover samples were compared by means of particle size distribution. The torrefied material was found to be more brittle and reduce in particle size more easily than the non-torrefied material. Results from the testing support the concept of a self selection process where torrefied biomass is separated from non-torrefied biomass. The data from the ball milling testing was used to design a self selection torrefaction system.


Copyright Owner

Jeremy Brue



Date Available


File Format


File Size

76 pages