Production Process Wood Pellet From Wood Biomass. Indonesia is the highest biomass potential in ASEAN countries so that the chances of developing wood pellet industry is huge.

1. Wood Pellet
Production Process of
From Wood Biomass
Eko SB Setyawan

2. Overview Pellet
Various types of pellets (wood pellet, torrefied
wood pellet & charcoal pellet) Biomass decomposition regimes
-White pellet = wood pellet are made of sawdust or planer shavings without bark
-Brown pellet = wood pellet are made of bark containing raw materials
-Black pellet = torrefied wood pellet
Wood pellet : Property class A1 represents the highest quality level that is particularly relevant for private end
users. In property class A2, the limiting values for the ash content, the NCV, the nitrogen and chlorine content and
the ash melting behaviour are less strict. This property class is mainly relevant for commercial users operating
pellet boilers with higher nominal capacity. Pellets according to property class B are relevant as industrial Pellets.
The main factors distinguishing : calorific value, ash content and ash chemistry
Pellets made from bark containing wood fractions such as forest wood chips, industrial wood chips with bark
and short rotation coppice (SRC) would comply with A2 pellet class. That’s mean Calliandra Pellet is A2 Pellet.

3. Overview Pellet
Usually brightly colored pellets from softwood and the dark one
from hardwood. But pellets are made of soft wood from all
parts of the tree ("whole tree") including bark will make darker
pellets. So it is difficult to determine the quality of wood pellets
of color alone.
The length of pellets on the market varies from different manufacturers.
Production of wood pellets requires consistent length and minimize the
variation.
Wood pellet diameter varies from 6 mm to 20 mm. Diameter of 6 mm is
commonly used for home heating, whereas the 8 mm diameter upwards
commonly used by industry and power plants.
Generally hardwood pellets are preferred, especially for the stove
and fireplace because it naturally has a lower water content,
denser, longer burning and heat such as coal.
Standard grade fuel is usually up to 3% ash content, while premium grade is less than 1
percent. Premium pellets are usually produced from hardwood or softwood sawdust
containing no tree bark.

4. Overview Pellet
Wood
* Proksimate and ultimate analysis to determine the compounds and chemical elementsof
wood pellets can also be done to complete product knowledge and commercialization

5. A. Process Technology of WoodA. Process Technology of Wood
Pellet Production

6. Essence of Wood Pellet Making Process
• Essence / Philosophy of wood pellet manufacturing process is
compaction (densification) of biomass to facilitate handling,
transportation and utilization such as combustion, pyrolysistransportation and utilization such as combustion, pyrolysis
and gasification. In order produced a quality product
(standard and stable) it is necessary to the selection of raw
materials, preparation of raw materials such as particle size
uniformity and the dryness, conditioning, add adhesive and
so on before compacted (pelletizing). Raw materials are
categorized wood waste or woody biomass that worth as
wood waste.

7. Process Variables
• Raw Material Type
• Size of Raw Material
• Moisture Content• Moisture Content
• Hardness
• Density
• Product Size (Wood Pellet)
• Ash Content
• Raw material chemistry
• Ash Chemistry
• Contaminant etc..
These variables have tended to make pelleting
more of an “art” than a “science”, through
significant strides are being made in the
sophistication of this process, bringing these
variables under more control.

8. Process Technology of Wood Pellet Production Plant
• Standard Process of Large-Scale Wood Pellet Plant
*Optional
• The highest cost components at:
-RawMaterial-RawMaterial
-Drying

9. Comparison of Wood Pellet Plant
A typical of large scale wood pellet plant. Left: 750rb TPY-Georgia, U.S.; Right: 5 TPH - Tenesse, U.S.
A typical of small scale wood pellet plant. Left : 500kg/h- China; Central: 500kg / h - Argentina; Left: 350kg / h; China

10. Statistic of World Wood Pellet Production
• Russia's total production 3,093 million tonnes /
year by the largest plant in Leningrad capacity
of 900,000 tonnes / year, the smallest in
Galway 2500 tons / year (2011).
• Total U.S. production of 5.481 million tons /
year, with the largest plant in Georgia a
capacity of 750,000 tonnes / year, the smallest
of 10,000 tons / year is found in many places
(2011).
• The total production of Canada 2.958 million• The total production of Canada 2.958 million
tons / year; China's total production of 792 000
tonnes / year; Japan's total production of
110,000 tons / year; total Indonesian
production of 80,000 tons / year (2012).
• Prediction of wood pellet demand continues to
increase. In 2010 the global consumption of 16
million tons / year; 2015 predicted 37 million
tons / year and in 2020 predicted 59 million
tons / year.

11. Wood Pellets Export Ports

12. Logistic of Large-Scale Wood Pellets Marketing
(Reference of Canada)

13. Biomass Potential of Southeast Asia
Indonesia is the highest biomass potential in ASEAN countries so that the chances
of developing wood pellet industry is huge.

14. Raw Material
The level of dryness (MC) holds a vital role in the production process of wood pellets. Waste from
processed wood such as furniture industry in general is dry, while the forest or plantation is still wet,
so it needs drying before being processed into wood pellets.

15. Drying Process The Raw Material
• Judging from its use; timber can be divided into: 1. carpentry and wood
crafts; 2. timber industry; 3. firewood. All require drying before use.
• Wood holds moisture in two ways: as free water in the cell cavities and
bound water in cellwalls. The definition of free water is water that is
contained within the cell cavity, which is easily in and out of the water,
(hygroscopic). While water is bound water contained in the cell wall,
where the water is rather slow exit and entry.
• The variables that affect the wood drying process: 1. Wood, 2. moisture
content, 3. heat, 4. carrier medium heat, 5. air circulation, 6. air
temperature, 7. humidity, 8. dryer equipment (machine) , 9. drying
technique and 10.time.
•Wood drying process will run faster if the air temperature is higher, the lower theair
humidity and velocity of air circulation around the surface of the wood morequickly.
•Lighter wood in general will dry faster than heavier wood, because light woodporosity
higher than the heavy woodporosity.
•Drying techniques are used to optimize the process variables, such as: raising the air
temperature, the humidity of air (using dry air), increase the velocity of circulation of dry air,
extending the contact between the wood dried with dry air, in order to get dry wood withthe
times relatively fast.
•Drying by the sun with a relatively low temperature (40-60 C) also minimizes emissionsof
organic compounds (VOC = Volatile Organic Compound) smelled of wood.

16. B. Effects of Moisture Content in
Wood Pellet Production Process

17. Size Reduction Stage

18. Size Reduction Stage
• Woodcrusher (sawdust maker) hammer mill type
are generally only able to work on the moisture
content max. 20%.
• Timber harvest generally have a high moisture
content of about 50% that need drying prior to
being fed into a hammer mill.
content of about 50% that need drying prior to
being fed into a hammer mill.
• Calliandra or gliricidia rod size can be fed is small
average only 5-10 cm enough with 1-step process
type hammer mill. However if the size is more
than it can use a combination of wood chipper
crusher and hammer mill or drum-type cutter.

19. Illustration of Wood Crusher Equipment
Hammer Mill
Wood chipper and hammer mill
Hammer Mill

20. Pelletizing Stage

21. Various Types of Pelletiser
For pelletizing highly fibrous biomass L/D = 8,5-9 : 1
For pelletizing wood L/D = 8-10 :1
For small
capacity
<500kg/hour
For medium and large
capacity; the most
popular
rarely used, laboratory
scale application
For flat die machine the length of of hole is shorter than ring die machine, that’s mean
durability of pellets from ring die machine is better than flat die machine
rarely used, laboratory
scale application

22. Commercial Pelletiser
Commercial Pelletiser:
there are two kinds, namely
the flat die and ring die. Flat
die: high operational cost
(rapid equipment wear and
more maintenance), used
for animal feed wood
pellets or small-scale
(<500kg/day), the price of
FlatDie Ring Die
(<500kg/day), the price of
equipment is cheap . Ring
die: low operational cost,
the equipment (not quickly
wear out and a bit of care),
a popular and widely used
wood pellet production
capacity for medium to
large (> 500kg/hour), the
price is expensive.

23. Analogy Flat Die Vs Ring Die = Motorcycle Vs Car
Vs
xxIn the context of a conveyance with a particular load: Motorcycle engines are generally
small cc (100-500 cc) so that the payload capacity is also small, whereas when a large
engine capacity 1500 cc and above example, it is more suitable to be installed or
made cars for effectiveness the transport efficiency, aesthetics, handling, safety and so on
rather than made a big motorcycle.

24. - Carbon steel alloy: strongest die, cheapest price, not
corrosion resistant, rugged die surface friction and
thus greater compression so that the wood
pelletsproduced harder.
Material Die Almost all manufacturers of wood pellet line
also ring die and roller production, and there
are also that specifically sell as below :
-Stainless steel alloy: corrosion resistant, the price is-Stainless steel alloy: corrosion resistant, the price is
more expensive, because the die surface is more
smooth, then the depth of the die takes longer to
produce hard wood pellet.
- High chrome alloy: highest corrosion resistance, start-
ups easier, because the die is smoother, then the
depth of the die tajes longer to produce hard woor
wood pellet, the price is the most expensive.

25. Characteristics Raw Materials
Requires Different Shapes and
Sizes of Die
Each die (mold) suitable
for one type of raw
material !!!
Die can not "generic" for all biomass

26. Pelleting Stage
• Too high or too low levels of moisture in the wood in pelleting process will cause• Too high or too low levels of moisture in the wood in pelleting process will cause
the failure of this process.
• Toget good quality pellets, the average temperature on the die 125 C; Canada
requires maintaining a temperature of 85 C for a minimum temperature of the die.
The higher the temperature the better the quality of the pellets.
• Efficiency wood pellet plant that can be accepted is 130-200 kWh / ton, without
drying system.
• Fuels that are used during pellet production may produce a maximum greenhouse
gas (GHG) emission of 100 kg CO2 per tonne of pellets. This value can be achieved
as long as biomass fuels are used for raw material drying and can be lower if use
sun drying.

27. Pelletisation Process # 1
Phenomena in Ring Die Pelletiser Close up at Die Channel, Pelletiser

28. Pelletisation Process # 2
Thermographic View in Die Pelletiser
Source : Serrano et al 2011 Elsevier

29. When Raw Material Too Wet
• Too high moisture content (too wet) will cause the
pressure (compression) is very high on the die. This
makes the temperature rise and produce steam in large
quantities. The high pressure will make the motor work
too heavy and also potential to make die clogged. This
condition also affects the bearing in the roller. Thecondition also affects the bearing in the roller. The
resulting pellets will also be very soft and easily
broken. Despite high compression but adequate
temperature which makes the lignin out as the
adhesive is not reached. Because of the high moisture
content, the pellets will expand and release moisture,
consequently pellet surface is not smooth and
cylindrical as it should.

30. When Raw Material Too Wet
Wood pellets are soft and easily broken when using raw
materials too wet (high moisture content).
Wood Pellet will be damaged or destroyed on Cooling stage
when the moisture level is too high (too wet).
Scheme wood pellet
cooling with aircounter
flow

31. When Raw Material Too Dry
• Because the raw material has a low
density and lack of moisture
content (too dry) then the roller is
not able to perform an adequate
compression in the die. The lack of
pressure also resulted in a lack of
heat and lignin are not able toheat and lignin are not able to
come out as an adhesive in the
pellet. Because the raw materials
can not generate enough friction
and tension / compression of the
material will be slide freely inside
the die and consequently does not
form pellet.
Pellet was not formed when using raw material
is too dry (low moisture content)

32. Cooling Mechanism
When wood pellets out of pelletiser then the temperature is very hot,
soft and generate steam. Before pellets can be stored and used then the
condition to be cool and dry. The simplest way of cooling of wood pellets
is so cold in the room laid it by itself at room temperature. Counter flow
cooler is cooling type that common used in wood pellet industry
currently with use the direction of the air and product of wood pellets in
opposing directions. Cooling gradually will improve quality, reduce cracks
in the surface and "fine". Wood pellet out of the cooler with moisture
content to about 8% at temperatures ranging 5-10 C from room
temperature. Almost all coolers fitted screen to filter "fine" / "powder" of
wood pellets. "Fine" / "Powder" is then returned to the pelletiser to bewood pellets. "Fine" / "Powder" is then returned to the pelletiser to be
used as raw material again.
Left: Schematic of the
equipment counter
flow cooler; Middle:
photo commercial
cooler; Right: the
fancy wood pellets
cooled sufficiently
smooth and shiny
surface.

33. C. Pelletiser Characteristics and Maintenance
The Equipment Including Pelletiser

34. 6 Considerations as a Success Key of Pelleting
Success Pelleting = Quality Pellet
1. The relationship between the quality of raw material,
capacity of machines and pelleting processes(pelleting
operating conditions) must be synchronized.
2. Capacity friction on the die. The greater the friction the
higher the density of the pellets.
3. Material and surface of the die and roller. Die of stainless
steel has a smooth surface and corrosion resistance so that
the start up easier than die from carbon steel, but increase
friction then deepened the depth of the hole (die hole).friction then deepened the depth of the hole (die hole).
4.The ratio of length and diameter of the holes inthe
die.
5.The thickness of raw material layer on the die and
thus the thickness of the material is pressed into thedie.
The optimum thickness is generally 1 mm
6. Compression frequency (rotationalspeed).

35. The Height of Roller and Carpet
Carpet is a thin layer of material that is pressed, which is located at the top surface of the die. When the
incoming raw materials to pelletiser it will be driven by the roller and forming carpet. The more materials
put into pelletiser it will further add to the carpet. Carpet is then pressed into die hole and produce
pellets. So for material that can form a pellet, initially to be able to form a carpet.
1 mmGap
Generally carpet with a thickness of 1 mm is the optimum condition between pellet
quality, energy consumption and equipment wear rates.
>1mmGap
Enlarge the gap between the roller and die, will increase the energy requirements
needed. If the roller is set above 1 mm, then it is likely that the pressure generated
will not be sufficient between the die and roller. Without enough pressure thenwill not be sufficient between the die and roller. Without enough pressure then
there is no heat, so no adhesive is removed and the carpet is not formed, so that
the pellet is not formed. Only in very special conditions so it is rarely applied to> 1
mm gap in the production of pellets.
< 1mmGap
When the roller and the die contact means no space to form a carpet, so the
material is pressed directly into the luabng die, resulting in pellet quality will
decline. More importantly, when the inter-metal contact occurs it will significantly
reduce the life of the roller and die.
Tip: When setting up the roller gap, the characteristics of raw materials need to be considered, for example the
density of the material and gluing capabilities. 1mm gap is recommended for almost all the materials but try
variations of the gap would be beneficial. All pellet production is a matter of reducing the need for energy and
equipment wear rates while simultaneously improving quality and productivity pellets. This is why the quality of
production of pellets requires special skills.

36. Gluing Characteristic In Wood Pellet
Production
• Variables including raw materials and moisture content, particle
size, shape, and distribution, hardness and lignin content has a
major influence on pellet quality and selection of adequate
process conditions. The presence of a liquid such as moisture for
generating pelleting style interface (interfacial forces) and
capillary pressure, thereby increasing the bonding of particles.capillary pressure, thereby increasing the bonding of particles.
• There are 3 stages in the compaction of biomass, including
pellets. Stage 1: formation of particles arrange themselves to
form a solid enough. Stage 2: particles push each other and form
properties such as plastic and elastic deformation, thus
enhancing the contact between the particles significantly;
particles become bound by van der Waal's electrostatic force.
Stage 3: a significant decline in volume due to the high pressure
/ compression so that the density pellets can be achieved.

37. Deformation Mechanisms of Biomass Powder Particles Under
Compression #1

38. Deformation Mechanisms of Biomass Powder Particles Under
Compression #2
Compression curve of biomass powder particles. Compaction process can be
separated into several stages: particle rearrangement, elastic and plastic
deformation, and hardening.

39. Susunan Cellulose, Hemicelullose
dan Lignin Pada Biomasa

40. Gluing Characteristic In Wood Pellet Production #1
Compaction of biomass such
as pellets with a pressure /
high compression will increase
the mechanical interlocking
and adhesion between
particles, thus forming bondsparticles, thus forming bonds
between the molecules in the
contact area. On raw materials
such as wood biomass
adhesion mechanisms can be
divided into styles adhesion
and cohesion, attractive forces
between the particles and
bonds interlocking.

41. Gluing Characteristic In Wood Pellet Production #2
Display of broken surfaces on pellets with a scanning microscope electrone (SEM)
a. Typical surface fractures on the pellet, which indicates strong adhesion
b. Typical surface fractures on the pellet which indicates a weak adhesion

42. Gluing Characteristic In Wood Pellet Production #3
Display light microscopy which showed the polymer melting and interlocking the fibers
(biomass)

43. Gluing and Quality of Wood Pellet
Particles "Fines" (Powder) formed due to the lack of adhesion during pellet
formation So that the performance of pelletiser and the finished product affect to
the percent fines. Pellet very strong when pressed vertically but easily broken when
pressed horizontally. Poor quality pellets made crushed / broken into pieces and
generate a lot of powder. Depending on the target market, the percentage of "fine"
that forms need to be declared or not. Premium quality wood pellets at a target of
fines should be less than 1%. CEN European standard specifications of the
percentage of "fines" that is allowed and in many cases a percentage of the fine
should be stated when sold. Packaging capacity also affects the occurrence
percentage of the fine, the smaller the container will create a smaller percentage of
fine.

44. Characteristic of Pelletiser
• Each material has different qualities and characteristics. The
parameter is the moisture content, density and quality of the gluing.
• When the quality of the raw material for wood pellets has the
appropriate quality, then after entering pelletiser and contact with
the roller and get the appropriate heat and pressure then the pellets
will exit. The blades can be added to set the length of pellets. And
after cooled pellets will be hard and ready for use.

45. Characteristic of Pelletiser
• Selection of quality raw materials greatly affect the quality of
wood pellet, and setting pelletiser include material thickness
and die, pressing time, pressing temperature and pressure
also helps improve the quality of wood pellet. Pressure can be
set by selecting the die, the die material and the distance by
roller. So for the production of wood pellet from many variety
of raw materials need to change feed speed to pelletiser andof raw materials need to change feed speed to pelletiser and
selection the pelletiser die. Ideally, the selection is also
related die compression ratio, for example, processing of raw
materials of softwood requires die thicker than hardwood
processing, for the same quality results pelleting.
• There is a difference between just making wood pellets with
making a quality wood pellet with minimum energy
consumption and maximum roller and die life.

46. Maintenance Equipment Including Pelletiser
Equipment used for wood pellet production exposed high
temperature and pressure, so that adequate
maintenance be essential to maximize the life of
equipment and reduce energy consumption.
A. Bearing maintenance
Particular equipment such as crusher type hammer millParticular equipment such as crusher type hammer mill
and pelletiser have much bearing, which reach high
temperatures during operation. Periodically check the
bearings needed to maintain the performance and life
of the equipment. Some equipment are equipped
with automatic lubrication for bearings.

47. Maintenance Equipment Including Pelletiser
B. Maintain Minimum Energy Consumption
Check the hammer mill and pelletiser can operate without
resistance will keep the energy needs minimum. For
example checking that there is no material cause additional
friction around pelletiser and roller.
C. What to Do At the End of Production
When the end of the production is very important to include
oily materials to pelletiser so production will be started
When the end of the production is very important to include
oily materials to pelletiser so production will be started
easily again for example bran with cooking oil. If the raw
materials are processed left in the die, then die cold so the
raw material in the die cold too and will harden. If it
happens then it is very difficult to start up production again
and may need to be drilled the clogged die.

48. Photos Some Equipments that Need Maintenance Includes Pelletiser

49. Receiving Station
• The raw material is received at the plant will calculated by :
1. Volume. Calculate the volume of wood in a car or truck tub
then multiplied by average density wood (100-150 kg/m3)
2. Weighing. Wood can be put in a sack and weighed with scales
or wood with truck minus weight of the truck with a truck
load scales. Estimated price of 10 thousand dollars.
Method 1 is cheaper and practical, but accuracy is not as good as
the method 2.

50. Packing Wood Pellet
• It is advisable to pack wood pellets to the large size, so if it does not use
packing machine-for example, directly from the cooler is not a problem,
because small amounts.
• Jumbo bag packing models with capacity 1 ton or 500 kg can be applied.
Generally, small scale of wood
pellet plant in Indonesia use
direct packing from cooler.
500 kg jumbo bag for
wood pellet
Jumbo bag for 1 ton
wood pellet

51. Packing / Bagging
A. Semi-Manual
B. Full Automatic

52. D. Wood Pellet Plant ConfigurationD. Wood Pellet Plant Configuration

53. Product Storage
• Wood pellet product storage in a dry air-vents.
Highly recommended to use a pallet to keep the
product dry. Some other guidelines such as the
adjacent column.

54. Safety in Wood Pellet Plant
• The things that need to be considered in the area
of plant :
Based on USData
- Wearing masks, boots, gloves and helmets.
- Avoid burning trash and the like that cause fire.
- No smoking.
- The electric motor and relay equipment must
be protected.
- Be careful when welding and cutting metal in
many areas of dry sawdust potentiallymany areas of dry sawdust potentially
dangerous.
- Avoid contact hot surfaces with dry sawdust, as
it could potentially cause a spark.
- Wood pellets should not be stored longer without
an adequate temperature monitoring*
- Beware against friction, collision and sparks
arising from hot bearings, moving parts, etc.
that cause accidents with dry sawdust.
* microbial activity will raise the temperature to 90 C of wood pellets which then could
cause a fire when oxidized. High moisture content and production process so that the
raw materials are not exposed to temperatures> 100 C will stimulate microbial activity.

55. E. Promotional Use of Wood Pellet for
Indonesia and AsiaIndonesia and Asia

56. Affecting Factors

57. Comparison of Wood Pellet With Coal
No. Factors WoodPellet Coal
1. CalorificValue 4000 kcal/kg andup 5000-5500kcal/kg
2. AshContent <4% 20 to40%
3. Pollution/Poisonous effluentSmoke No Smoke NoSulphur Sulphur,
phosphorousfumes
4. Moisture 8 %(max) 20 to35%
5. Efficiency ofboiler 75% 75%
6. Wastages/Loss 8-10% 15-20%
7. Labourusage Single person isenough Require two persons7. Labourusage Single person isenough Require two persons
8. Boilerefficiency Normal Fly ash deposit ontubes High wear &tear
9. Handling Easy because of packedmaterial Toughmaterial
10. Type ofFuel CarbonNeutral CarbonPositive
-Various advantages of wood pellets can be used as a bargaining postion sale price of wood pellets for coal
substitution in industry.
-For comparison: in the U.S. almost all the wood pellets used for household heating with pellet stove, while
the majority of wood pellets in Asia are used for co-firing with in coal powerplant.
-Most wood pellet production process also with debarking (remove the bark from the wood) for reducing
the ash content. Because consumers of wood pellets in Indonesia and Asia is an industry that is generally
more tolerant to higher ash content then there is not a problem without debarking.

58. F. How to Get Raw Material Supply
with large volumeswith large volumes

59. Cultivation of Short Rotation Coppice (SRC)
with Energy Forests / Plantations

60. Comparison the SRC Productivity Between
Indonesia and Europe / America
Productivity of woody biomass for 1 year Calliandra in Indonesia (tropical
countries) = 4 years Willow in sub-tropical countries.
(Calliandra)

61. Availability of Land in Indonesia
Source : YETTI RUSLI PRESENTATION

62. International Price of Wood Pellet

63. Thank you
Eko SB Setyawan Mobile :+62 8132 884 1805
Biomass to EnergyEntrepreneur
eko.sbs@gmail.comeko.sbs@gmail.com
@ekosbs http://biomassproject.blogspot.com/