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Making
Pellets
Making pellets is a skilled process, and even more so with
the PelHeat unit. To offer a affordable pellet production
unit to the small-scale producer, the user needs to prepare
the raw material themselves. Thus, more education and skill
is required, to know if a material is suitable, and if not
how to prepare it. Use the information below to learn more.
 
Principle
Principle
Once the material has been reduced to a uniform size through
the hammer mill, the material is then placed into the pellet
mill. The pellet mill comprises of a roller and die plate,
which either has 6mm or 8mm holes. The roller compresses the
material into a carpet, between the roller and die plate. As
more material is added, this is then added to the carpet, so
the bottom of the carpet is forced through the die holes. As
this process continues this will result in a pellet been
produced.
Pressure
For a carpet, then pellet to be produced pressure is
required. Pressure is acquired by using material that will
give resistance between the roller and die. This is why
the qualities of the material need to be correct, see the
Raw
Material page for more information.
Heat
Heat is produced as a result of pressure. Heat is required
to release moisture, and binding agents within the material,
so the material can be compressed into a carpet, then a
pellet.
Binder
Binder is required so the material can be compressed
together. Many biomass materials like Wood, have enough of
their own natural binder, lignin. Pressure causes heat,
which cause moisture to evaporate, which releases lignin to
bind the material together. Some materials require more
moisture than others to release lignin. Some materials
do not contain enough lignin, here extra binder is required.
Used cooking oil and vegetable oil can be added to the raw
material as an extra binder.
Power
Sufficient power is required to produce the required
pressure. This is why the PelHeat unit uses a Perkins 4
cylinder engine, with 50bhp. This engine is not only
powerful, but very efficient, meets the latest European
emissions regulations, and can run on 20% bio diesel. Visit
the Products
page to find out more.
More on Pellet Production
Check
the
Resources
page
for websites, and for more information.
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Pellets Index
Testing
Material Test
To test, place some of your milled raw material in the
pellet mill. If smooth, compact pellets are the result then
the raw material is suitable. This means a continuous
process can take place, with the raw material going into the
hammer mill, and straight into the pellet mill.
Conclusions
If smooth, compact pellets are not produced, what did happen
will indicate how the material needs to be prepared, before
it can make quality pellets. Please read the
Making Pellets guide for
more information.
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Pellets Index
Cooling
Why Cool
When the pellets exit the pellet mill they are very hot,
soft, and still releasing moisture. When the pellets cool,
the binder begins to stiffen the pellet. After a few minutes
the pellets are hard, and can be used in your boiler or
stove.
How to Cool
If the hot pellets are kept in a heaped mass straight out of
the pellet mill, they will take quite a long time to cool.
Spread the pellets out, so air can circulate around them,
this will dramatically speed up the cooling process. For a
cost, there are pellet coolers in the market.
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Pellets Index
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