Wood Pellet
Wood pellet line is the process of making wood waste into solid fuels
which are used for burning purposes. Wood Pellet is generally made
from compacted sawdust and related industrial wastes from the milling
of lumber, manufacture of wood products and furniture, and
construction.
IDAH offers complete process solutions and consultancy that will help
you integrate smoothly into the wood pellet business. In producing
wood pellets, there are some important variables that we need to pay
attention to, such as raw material purity, moisture content, particle
size, and pellet strength.
Raw Material
The raw material for wood pellets may differ according to the
source. It may come in a log shape, board shape, sawdust, and many
other. A pre-crushing may be needed to reduce particle material size
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Pre-grinding
Optional step for coarse material.
Pre-grinding will lower the
energy needed for post-grinding.
Daily Tank Storage
Daily tank storage will contain the material needed for production
that day.
Dosing and Weighing
The material will be dosed based on the formula.
Post-grinding (optional)
Post-grinding is the final size reduction in the system.
This step can be omitted if not necessary.
Mixing
In this step, some water, oil, or other liquid may be added to help
the pelleting process.
Pelleting
Pelleting starts with pre-conditioning, adding steam to further
hydrate, and cook the material before entering the pelleting chamber
to be formed into pellets.
Cooling
Cooling utilizes ambient air to cool down the hot pellet from the
pellet mill.
Thorough cooling is needed to prevent condensation inside the
packaging.
Packing
Packing gives protection to the pellets and also give easiness to
handle and transport to customer's hand
Pelleting process description for wood pellet
Pre-crusher system Some
materials will have big dimensions, so this pre-crushing is needed to
reduce the size.
Raw material intake system Consisting of tip hopper, mechanical conveyors, and elevators into
storage bins. For wood pellet, the material can be sawdust, straw meal,
and other biomass sources.
Grinding system
A size reduction process for raw materials that contain large
particulates. The ground material is conveyed to storage bins. (Location
for this grinding system can be designed to suit the process flow that
follows).
Mixing system
Other sources like liquid and oil are now added and mixed with raw
material in batches. After mixing the material is ready for pelleting.
Pelleting with Pre-conditioning
The mixer feeds down through a feed hopper into the feed screws which
meter the ingredients into the conditioner. Due to its nature, biomass
material will have low flowability. A force feeder is needed to feed the
material to the pelleting chamber. IDAH's pellet mill produces pellets
at high capacity, low energy consumption, and high pellets quality. With
a special die and rolls design, the production cost can be reduced to a
minimum. Rolls combination is designed for easy adjusting the clearance
between the rolls and the die. With different raw materials, appropriate
clearance will help rolls work and achieve the maximum capacity. Sizes
of pellets are controlled by hole diameters of pellet dies and the
compression ratio of the die is crucial to the high quality of pellets
and production throughput.
Cooling
After the pelletizing process, the wood pellet is hot. Cooler lowers the
temperature of the hot pellets to ±5 °C of room temperature and reduces
the moisture by using ambient air. Cooling would extend the shelf life
of the wood pellet.
Impurity and dust sieve
All pellets will go through a vibration sieve to remove any irregular
pellets or dust.
Bagging and sealing system
Weighing cell and bagging machines put pellets into bags with chosen
quantity and seal the bags for storage. Finished products can also be
loaded by trucks or in container bags.
Features and Benefits of IDAH Process Design and Equipment
IDAH firmly believes in a strategy of design fit for purpose. We
recognize the constraints our customers face with rising ingredient
costs, energy costs, and overheads costs, yet in the face of these
challenges, it is still expected that high-quality products be supplied
into a very competitive market. Our design philosophy is to work
continuously to refine and improve processes and equipment to maximize
the success of our customers. The following describes some of the
features and benefits resulting from this philosophy.
Rugged 24/7 Design
We design our equipment for continuous operations and fulfill the
expectation for minimal downtime. Our mission is to see our equipment
still working years after installation, with only maintenance required
being routine maintenance caused by normal fair wear and tear.
Formulation
Two perspectives are influencing the formulation: culturing performances
and efficiency of the machinery. For example, choose the right wood
source is essential. Inappropriate wood sources will lower the steam
incorporation level and causes jams at the pellet mills. Fat and
moisture content play inseparable roles in the hammer mill throughput.
Pre-conditioning
The independent drive on each shaft of the IDAH twin shaft lowers power
consumption and noise. The paddles' reverse rotation allows completely
emptying the chamber. The misting steam and water injectors further
improve conditioner performance. The following conditioner system used
steam jacketed (or heat jacketed) to create a homogenous mix with little
to no free water. Insufficient pre-conditioning will cause cracks on the
pellet surface and creating dust fines.
Cooling
The counterflow cooler is used for cooling pellet and extrudate. Warm
(hot) pellets get into the cooling chamber, the suction fan will
transport out the air inside the chamber, and fresh ambient air will
enter the chamber from the bottom, promoting pellet cooling action. When
pellets are accumulated and touch the high-level limit sensor, a
pneumatic discharge swivel valve will operate immediately to discharge
the products. Counterflow air heat exchange ensures to achieve high
cooling efficiency.
Specification of Pellet Mills (for Wood Pellets)
| Model |
PM-42RB |
PM-53RB |
PM-635RB |
| Main Motor (HP) |
150 |
250 |
350 |
| Operation Capacity1 (t/h) |
0.4-0.6 |
1.3-1.5 |
1.8-2.0 |
Note:
1) Wood Pellets, pellet die hole size Ø 8.0 mm, moisture content
< 12%, oil content <7%