From the NCSU Bulletin – by David Hunt
The mound of woodchips piled up behind an old barn in Raleigh, N.C.,
could fuel a pretty spectacular bonfire. But as Chris Hopkins surveys
the mound, he has a better idea. Hopkins, a doctoral student in
forestry at NC State University, is part of a team of researchers
working to turn woodchips into a substitute for coal.
Nearby
the team members have set up a tall metal machine called a torrefier
that performs modern-day alchemy. Woodchips go into a large funnel at
the top of the machine and come out as hard, dry, black pellets at the
bottom. In the process, they've changed more than just their
appearance. They've been physically and chemically altered – through
heat and pressure – to make them denser, drier and easier to crush. more…