Converting Waste Agricultural Biomass into a Resource - UNEP

Soundproofing and Insulating Materials 178
Italy, Commercial
Crop
Residue
Auxiliary materials
Process
Equipment
Main Product
Kenaf
Kenaf fibers
Hemp
Pulping
Separator, Scutching units
Soundproofing systems, thermal insulation of
walls, floors and roofs, automotive components,
and ecological building
Technical Description of Technology
Kenaf fibers can be pulped either in whole stalk or separated forms. Although
various pulping technologies have been tested with kenaf, the only
commercial operations presently using kenaf are kraft (sulfate) mills in
Thailand using whole stalk and in North Carolina using bast fiber. Kenaf is not
the principal fiber source for either mill. Most of the work to date on kenaf for
newsprint and other printing and writing grades has focused on a modified
thermo-mechanical process, which is energy intensive.
Detailed Process Description 179
- Roundbales: after preparing the ground, seeding and cutting with special
mechanical equipment, they harvest with a roundbaler and transport the bales
to the first processing system, preferably located within a radius of 40-50 km,
for transport requirements; usually, for the system to be able to work at full
pace, it needs at least 1000 hectares of cultivation and roughly fifteen skilled
workers.
- At the plant: it is designed according to the technologies for flax, modified
down to the definition of blades and mechanisms suited to cope with the
extraordinary strength of hemp fiber; the material of the bales is analyzed
(quality, weight, moisture, impurities, state of maceration) and stored.
- Separating machine: after removing the bale rings manually, a special belt
transports the bales to the aforesaid machine, which supplies the scutching
units with prearranged quantities of material.
- Scutching units: the stems are stripped of their cortical and woody parts
without being torn; these parts are collected on a second belt and sent to
another processing sector.
178 http://www.hort.purdue.edu/newcrop/cropfactsheets/kenaf.html
179 http://www.kenaf-fiber.com/en/prima-lavorazione.asp
330