Technology of production of fuel pellets from sawdust with their own hands and in factory conditions

The importance of efficiently and sustainably heating our homes has increased. A growing number of homeowners are looking to alternative heating solutions due to rising energy costs and growing environmental concerns. The usage of fuel pellets manufactured from sawdust is one of the innovative solutions that has gained popularity.

One excellent way to recycle wood waste and turn it into a useful heating source is to turn sawdust into fuel pellets. The technology underlying pellet production is quite simple and adaptable to various operating scales, so it’s worth a try to do it yourself or investigate factory production.

Making fuel pellets from sawdust can be a satisfying experience for individuals who prefer do-it-yourself projects and are hands-on. It lets you be environmentally conscious and in charge of your heating needs. However, in larger-scale production, factories have optimized their processes to generate high-quality pellets quickly.

Comprehending the technology involved in converting sawdust into fuel pellets can be advantageous for anyone interested in the pellet production business or as a homeowner trying to heat their home. This post will explore the procedures and techniques used to make these environmentally friendly heating pellets in both factory and domestic settings.

Production Method	Description
DIY at Home	For DIY fuel pellets, start by collecting dry sawdust. Mix the sawdust with a binding agent like vegetable oil or water to form a paste. Then, feed this mixture into a homemade pellet press to shape them into pellets. Allow them to dry thoroughly before use.
Factory Production	In factory conditions, the process is more automated. Raw sawdust undergoes a drying process to reduce moisture content. Then, it"s fed into a large pellet mill where high pressure and heat compress the sawdust into pellets. Quality control checks ensure the pellets meet standards before packaging.

Producing fuel pellets from sawdust can be done both at home and in factory settings, offering an eco-friendly and cost-effective heating solution for homes. The process involves compressing sawdust under high pressure to form small pellets, which burn efficiently and produce less smoke than traditional wood fuels. At home, you can use a pellet mill to make pellets from collected sawdust, ensuring you have a consistent and renewable heat source. On an industrial scale, specialized machinery and processes are employed to produce large quantities of pellets for commercial distribution. Whether DIY or factory-made, fuel pellets from sawdust provide a sustainable heating option that helps in reducing carbon footprint and energy costs for heating and insulating your home.

Production technology

The coarse crushing of raw materials, which calls for the use of specialized equipment, is the initial step in the production of this kind of fuel. Its weight and composition can change based on the grade. The volume of the final particles can’t be greater than 1.25 cm3. The next step is drying (the truth is that, in terms of technology, raw materials should not have more than 12 percent humidity prior to pressing).

Additionally, the final product is crushed to the point where the first-grade particles are no larger than 1.5 millimeters and the industrial type can have particles as large as 4 millimeters. Following that, raw material water treatment is carried out. Its fundamental idea is that the desiccated particles must be restored to the necessary state. This is because, when raw materials have less than 8% moisture content, the particles under the press’s action essentially do not stick together.

Pressing is a crucial step in the manufacturing process for granulated fuel. Different pressing machines with flat or cylindrical matrices are used for this process. The pellets are cooled at the end of the process in order to dry them out. The final steps in the production of this kind of fuel are packing and sieving, which is required to keep the pellets from sticking. Because all waste that is received is merely recycled, this type of production is very profitable.

Raw materials for pellet production

The raw material used to make pellets is wood chips, roughly 1 mm thick and up to 3–4 mm long. The benefit of producing pellets is that they don’t need to be specially prepared, unlike chipboard, for example. Metal inclusions and mineral impurities are prohibited in raw materials. The color of finished pellets is influenced by the raw materials used in their production:

Bark-covered and possibly rotted wood yields black pellets.

The lowest-grade pellet on the picture is the black pellet. Black pellets are made by drying inferior chips that contain dirt, bark, and other impurities without following technological guidelines.

Unbarked wood is used to make gray pellets. The pellets have bark inclusions, as the picture demonstrates. Inclusions might not be seen if the chip size is smaller, but the pellet will still have a dark color.

The gray pellet in the picture.

Fine debarked wood is used to make light-colored pellets. Pale-colored pellets are more costly than gray and black pellets because they produce more heat and crumble less.

The best possible pale-colored pellet.

The raw material has an impact on the quality of pellet gluing in addition to pellet color. The natural lignin found in wood is used as a binder during the pellet-pressing process. However, each species has a different amount of lignin, so the higher the lignin content in the wood, the higher the quality of the pellet. Click this link to read more.

The hardness of the wood is a significant technological factor in the pellet-making process. The truth is that the harder the wood, the more the punch, matrix, and cutting tool wear.

Basic requirements for raw materials for pellets

Moisture

For industrial pellet pellet pelletizers, the raw material moisture content should range from 8% to 15%. In other situations, the raw material needs to be dried or, conversely, steam treated.

Ash content

The percentage of non-flammable residue remaining after burning the batch is known as the pellet ash content. This indicator is up to 1% in premium pellets, per EN Plus A-2, and 0.5-0.7% in premium pellets, per EN Plus A-1. Over time, a fuel with a high ash content can clog the chimney and combustion chamber.

The EU is currently tightening laws governing the atmospheric release of combustion products. Chemicals like azor, chlorine, and sulfur should be present in minimum amounts in raw materials for pellets.

High energy value of the material

The primary use value of pellets is determined by the raw material’s calorific value, or the amount of heat that can be produced through combustion. Good raw materials have a high nutritional content. The material’s freshness is one factor that affects this parameter. Wood that has decayed loses some of its potential energy.

Suitability for pelletizing

Certain materials can press and prepare more easily or more difficultly. Furthermore, the difficult-to-granulate raw material may result in pellets that are less dense and durable. The strength of the pellets is increased by adding different additives.

Raw material costs

These expenses raise the price of raw materials, which already includes the price of purchasing and shipping. Production might not be financially feasible if the total cost of raw materials is excessively high.

Advantages and disadvantages of fuel pellets

Pellets are a natural fuel with an ash content of no more than 3% that is environmentally friendly. Most often, waste from the woodworking and agricultural industries is used as an initial material for the production of fuel pellets. These waste materials were previously just dumped in landfills, where they would eventually rot and, at some point, catch fire or, at most, start to simmer.

Fuel pellets do not contain dust and spores, are less prone to spontaneous combustion and do not cause allergic reactions in people during combustion. The main difference of fuel pellets from wood is a higher level of dryness, as the moisture level of pellets, unlike wood, is only 8-11% compared to 30-50% for dry firewood. In addition, the density of fuel pellets is more than twice as high as that of wood. As a result, these qualities provide fuel pellets with a higher level of thermal conductivity in contrast to firewood or wood chips, because in the process of combustion of one ton of fuel pellets more than 3.5 thousand kilowatt/hours of heat is released, which is more than 1.5 times more than traditional firewood can provide.

Among other benefits, fuel pellets offer the most convenient long-distance transportation of this material due to their high and consistent bulk density. Fuel pellets’ uniform consistency, small size, and regular shape make it easy to pour the material through specialized hoses, opening the door to complete automation of the fuel’s loading, unloading, and burning processes.

Raw materials

• Sawdust and shavings. Pellets from sawdust are considered to be pellets of the first category and are characterized by the lowest ash content combined with a high specific heat of combustion. They can be used in any heating boilers, including low-power installations. Wholesale cost of sawdust starts from 100-150 rubles./м³;
• Wood chips. For the production of fuel pellets, sawmill waste, as well as crushed residues of substandard wood are often used. Due to the presence of bark and roots, this raw material is less valuable, since the content of such impurities leads to an increase in ash content. Average cost of wood chips – from 150-200 rubles./м³;
• Peat. Top peat is used not only to produce pellets but also peat briquettes, which can be burned both in boilers designed for this purpose and in conventional fireplaces. The ash content of peat pellets is within 3%, which allows to classify them into the second category and successfully use them in industrial plants. Average cost of peat – 290 rubles./м³;
• Straw. This raw material for pellet production has the highest calorific value combined with an ash content of 4-10%. Therefore, straw pellets serve as fuel mainly in large CHP plants equipped with boilers of special design. The cost of straw – from 340 rubles./м³;
• Agricultural waste. Pellets can also be made from crop waste – sunflower, buckwheat, corn, flax. With ash content of 2.5-7%, this type of fuel requires installation of an automatic boiler cleaning system. The cost of sunflower husk – 180 rubles./м³.

When assessing raw materials’ quality, it’s important to consider a few fundamental factors that establish whether or not they are suitable for additional processing:

• The source material should not contain any solid impurities (stones, sand, metal), garbage and non-combustible mineral residues;
• The composition of raw materials must necessarily include lignin and organic resins;
• Humidity of the material should not exceed 35-40% (otherwise the production process slows down and drying costs increase).

Equipment

If you know how to make pellets yourself, you can solve the issue of having a reliable source of energy for your house or other location. Generally speaking, there are two primary categories of equipment used in their manufacture: mini-gradulators and industrial lines.

The second variety can be further classified into multiple subspecies based on how the drive is used. In this situation, a tractor power take-off shaft unit, an electric motor, or a diesel engine may be employed. The availability of raw materials and the circumstances surrounding the equipment’s continued use determine which type is selected.

Installation costs vary according to technical specifications. Specifically, the cost of a unit capable of producing 200–250 kilograms of pelletized fuel per hour will be slightly more than $6,000. Concurrently, the estimated cost of a robust industrial line that can simultaneously produce approximately one ton of solid fuel is $132,000. Experience has shown that the installations listed first are the most effective.

Pellet production as a business

It is evident that the process of producing pellet fuel pellets is centered on raw materials.

And the continuous supply of raw materials for processing is a crucial component of it. Pellets come in a variety of materials.

You can obtain the best-quality pellets by producing them from sawdust. They burn for the longest time and produce the most heat when they do so. They are the priciest kind of fuel pellets due to their superior qualities and features. Producing straw pellets yields the least expensive kind of biofuel. These pellets burn quickly and produce very little heat. In actuality, mixed pellets—which are made up of various waste materials—are produced very frequently.

One extremely promising business venture is the production of biofuel. Numerous businesses and utilities in Europe have already stated their intention to convert to fuel pellets. As a result, there will be a yearly increase in the demand for pellets, making high profits consistently possible. Researching the market is a prerequisite for starting a fuel pellet production company. After identifying possible clients, the next step is to look for raw material suppliers. The logistics phase will help select a location for the plant that has easy access to transportation interchanges, thereby reducing the cost of transportation.

It is not necessary to build technological facilities from scratch. You can rent a suitable room and equip it for production. This will save a lot of time and effort. Mini production of pellets can be established directly at the sawmill. You just need to agree with its management and equip the workplace. Such a neighborhood will allow to avoid transportation costs for delivery of raw materials at all. There will also be no problems with supply disruptions due to weather conditions, such as heavy snowfall or icy roads, which can interfere with long-distance transportation. Well, when all the issues of suppliers and customers will be settled, you need to get start-up capital, obtain the necessary licenses and you can safely start your own business.

5 Production technology

Generally speaking, the location of pellet production is close to the raw material source. Large woodworking companies frequently organize biomass pelletizing as a means of making waste materials more marketable. This method is also used in the process of making pellets from whole wood. Although most businesses concentrate on large-scale production, compact pelletizers designed for use in homes and small businesses have grown in popularity recently.

The stages of the technological process used by businesses to produce pellets can vary. The type of raw material used and its moisture content are the primary causes of this. Nonetheless, the following processes are present in every biomass pelletizing facility:

• pre-treatment;
• the actual pelletizing;
• post-processing of the obtained granules.

Pellet production technology

This is how the traditional manufacturing process appears:

• crushing into large pieces;
• drying;
• second crushing into small pieces;
• Mixing and water treatment;
• pressing;
• cooling and drying;
• packing;

The wood is first crushed and then shred for additional drying. No more than 25 millimeters in length, width, and thickness should be present in the crushed raw material. In addition to drying the materials and getting them ready for the second crushing process, this will make the drying process quick and high-quality.

The wet raw material is typically kept on the concrete surface to prevent it from combining with other materials (sand, stones). A scraper is used to feed the material into the drying machine. It is gathered by the operator and fed into the drying system.

It is worse to be pressed if the humidity is more than 15%. Additionally, pellets are not suited for boilers due to their high moisture content. As a result, before pressing, the raw material needs to be dried to a moisture content of eight to twelve percent. The ultimate moisture content ought to be approximately 10% +/- 1%. The most energy is used in drying out of all the processes. The combustion heat from one cubic meter of dense wood is required to dry one ton of pellets. Burning the bark would be best.

A product that has been thoroughly crushed emerges, with a maximum size of 1.5 millimeters.

The process of water treatment involves adjusting the raw material’s moisture content to the proper level. Pellets are less securely glued in the press if the humidity level is less than 8%. It is essential to dose the moisture in the mixing tank for this purpose. It is necessary to add hot steam when processing hard wood, such as oak or beech.

Following the press, the pellets have a size of six millimeters for individual consumers and ten millimeters for businesses. The press has a temperature range of seventy to ninety degrees Celsius.

The final product’s quality is guaranteed by the cooling process. After pressing, the product must be cooled. The pellets are then prepared for packaging.

Pellets are frequently transported and kept in placers. However, it is feasible to offer packaging in sizable bags. Pellets are purchased by individual customers in 20 kg bags.

Equipment

Pellet production lines can be completed in a variety of ways. Equipment suppliers give business owners the option of fully functional mini-plants that can produce dozens of tons of wood pellets per shift, or small standalone units with a capacity of 50–150 kg/h.

A pelletizer is the fundamental component of any complex; models with diesel engines, electric drives, and PTO drives are available on the market. Although it requires the tractor itself, the last option is thought to be the most cost-effective. Furthermore, all other things being equal, it is more practical for a budding entrepreneur to choose the second option over purchasing additional equipment because the remaining production equipment needs to be connected to electrical networks.

The technological line is only one part of the equipment needed for pellet production. In addition, the business owner will need to purchase a truck to deliver completed goods, a forklift to move raw materials, and office supplies for the director and accountant’s offices.

Equipping of the shop with 500 kg/h capacity

Name	Price, rub.	Packs	Amount, rub.
Shop (3001000 rubles.)
Hopper for raw materials	15000	1	15000
Shredder	140000	1	140000
Screw conveyor	58000	2	116000
Drum dryer	550000	1	550000
Hammer mill	132000	1	132000
Sawdust hopper	39000	1	39000
Mixer	80000	1	80000
Granulator	1212000	1	1212000
Scraper conveyor	57000	2	114000
Cooler	365000	1	365000
Pellet hopper	15000	1	15000
Weighing system	98000	1	98000
Pipelines	–	–	15000
Lighting fixtures	1000	10	10000
Installation of equipment	–	–	100000
Office (RUR 65800.)
Table	2500	2	5000
Chair	2000	2	4000
Chair	1200	4	4800
Computer	18000	2	36000
Telephone set	1000	2	2000
MFP	9000	1	9000
Light fixture	1000	4	4000
Router	1000	1	1000
Other equipment (616000 rubles.)
Truck loader	285000	1	285000
Hydraulic cart	9000	1	9000
Pallets	120	50	6000
Raw material moisture meter	26000	1	26000
Truck	290000	1	290000
Total:	3682800

Income and profitability

Eight tons of completed goods can be produced each day when two shifts of workers use the 500 kg/h line. When sold in small quantities, the first category pellets’ wholesale price is between 5800 and 6500 rubles per ton. Using these figures, the enterprise’s monthly revenue is calculated:

Calculation of profit

Name	Value
Shift duration, hours	8
Number of shifts per day	2
Working month, days	22
Working month, hours	352
Line capacity, kg/h	500
Volume of production per month, tons	176
Wholesale price, rub./т	6500
Monthly income, rubles.	1144000

Thus, an entrepreneur can make up to 1.14 million from the fuel pellet production business. each month in rubles

The amount of initial capital investments and ongoing costs must be considered when determining profitability and payback period:

Economic indicators

Name	Value
Income per month, rub.	1144000
Expenses per month, rubles.	756466
Gross profit, rubles.	387534
Tax USN 15%, rubles.	58130
Net profit, rubles.	329404
Profitability, %	43,5
Capital investments, rubles.	3856100
Payback period, months.	11,7

Principle of operation of the pellet production line

The pellet production line consists of several installations that need to be examined in detail. It starts with the vehicle that transports the waste from the production site to the recycling site. The brought raw materials are poured into a warehouse with a specially equipped "moving" floor. The movable surface of the floors allows the sawdust to be fed to the crushing machine at an adjustable speed. The feeding time is calculated taking into account the cycles of the crusher so that the device is not overfilled, but also does not stand idle. After the crusher, the raw material is sent to the drying chamber. After the relative humidity is brought to the required level, the raw material is sent for final crushing.

Here, waste materials like sawdust and others are ground into tiny sand-sized particles. The "wood flour" then begins to move in the direction of the pressing chamber. It travels through filters along the way to prevent particles that haven’t been crushed from entering. The raw material is treated with steam in the mixer prior to pressing. After everything is ready, the material goes into the pelletizer to be formed and compressed into pellets. The pellets that have been compressed land on a conveyor belt that transports them to a cooling room. Pellets that have cooled down gain hardness, and this is where technology stops. Only the final product’s packing and packaging in different containers comes next.

Multiple devices are included in the installation for the pellet production process. The first apparatus are the hydraulically powered "movable floors." They contain no particularly interesting devices; their sole purpose is transportation. The hammer crusher is the next. Grinding is done with a hammer, which works well with large sawdust and shavings but misses many small elements, as one can infer from the name. The pre-crushed raw material is put into the dryer, which removes extra moisture from the wood by keeping a high temperature.

Then follows the second pulverizer of the mill type, which allows to bring the material to the size of flour. It operates on the principle of millstones, so that all waste is simply grinded into a homogeneous mass. In the mixer, the raw material is treated with steam, which is supplied from special boilers with water, preheated to boiling point. Granulators for pellet production work on the principle of a centrifuge. They draw the "wood flour" inside, then press it under high pressure and extrude it through a special stencil, which gives the finished product the shape of pellets. At the outlet there is a special knife, which cuts the pellets to a set length. The cooling chamber is fed with cold air, which gives the pellets the necessary hardness.

Technological stages of pellet production

Pellet production technology involves multiple stages of production. The initial stage involves the delivery of small wood waste, such as sawdust and shavings, via a conveyor belt and pouring them into a designated warehouse featuring a movable floor. Sawdust is fed to the chain and scraper conveyor belt at a constant speed thanks to the hydraulic drive that powers the wedge-shaped stockers of the movable floor as they reciprocate.

The scraper conveyor’s primary function is to feed sawdust and wood chips into a specialized mixing apparatus and drying drum. A second fuel conveyor in the production line extracts sawdust to a partially finished product, which is then fed into the heat generator’s fuel hopper.

An auger is used to feed sawdust from the fuel hopper into the heat generator’s combustion chamber. Raw materials are transported to drying via the smoke pump’s discharge, which is formed by the movement of cold atmospheric air. Cold air is combined with combustion products, and the ratio of the mixture is automatically adjusted to keep the coolant at the proper temperature. Subsequently, the wet raw material and the heat transfer medium are combined and introduced into the drum dryer.

Due to a lack of a sorting process for incoming raw materials, raw material from the dryer’s drum is captured by special blades and fed upward through the coolant flow to the outlet, where a special stone catcher collects stones that fall into the raw material from the dumps. After the drying process is finished, the sawdust is fed into a large cyclone using a smoke pump-created discharge method. There, it precipitates and descends due to centrifugal force, and the waste heat carrier is released through a designated chimney.

Necessary equipment

Both industrial and domestic equipment is used in the production of pellets, with the latter being utilized to produce mini-pellets for home consumption. Electric and diesel motors power the production line. Also utilized are tractor shafts. This is the most typical choice. Up to 250 kg/h of pellet equipment can be produced by it.

Equipment required to set up a production line:

1. Shearer. It is designed to pulverize raw materials.
2. Drying drum.
3. Cooler. The apparatus is used at the final stages of production.
4. Press.
5. Mill and screw mixer.

You will need a drying drum at the very least.

The entire equipment acquisition will set you back about 2 million rubles. An electrically powered biofuel production machine can only be stationary. This significantly limits the equipment’s mobility and adds to the expense. It also necessitates outfitting a dedicated space, which raises the cost.

The tractor shaft and diesel engine installations are highly mobile. Its proximity to the woodworking facility is made possible by this. Because there is no need to pay for the transportation of raw materials to the location where pellets are produced, this option is far more profitable.

Other materials

There are large peat deposits in Russia that are good for pelletizing. The technology used to make wood pellets and briquettes is essentially the same for peat pellets and briquettes. Peat has a high calorific value of up to 21 MJ/kg, but these pellets also have a higher ash content of up to 5%. Boilers in municipal and industrial settings can use this type of fuel. Pelletizing and briquetting peat in Russia primarily has two benefits: exporting pellets to Scandinavian nations and supplying heat and electricity to non-gasified areas. Peat is acknowledged as a partially renewable raw material in Northern Europe, and its use in the energy sector is supported at the highest levels.

The waste paper pelletizing industry is relatively new, but it shows promise because this kind of raw material doesn’t need costly drying facilities. Pellets made of paper and cardboard produce a lot of heat and contain a negligible amount of non-combustible residues (although in some countries, it has also been established to pelletize old banknotes).

The cost of pellets made from horse and chicken manure is higher than that of pellets made from wood. It is an important and nourishing soil fertilizer. The price per kilogram of horse manure pellets is approximately 1.25 euros. Not only is it advantageous to recycle manure and droppings into fertilizers, but it’s also a necessary step because storing such waste poses a direct environmental risk.

The hydrolyzed lignin processing, which is a by-product of hydrolysis plants, is comparable. Despite having lignin reserves in the tens of millions of tons, Russia only has one lignin pelletizing plant, located in the Arkhangelsk region. Lignin is a great raw material for pellet production because of its high calorific value (more than 21 MJ/kg) and low ash content (less than 3%).

Growing the raw material base for fuel pellet production allows for the efficient use of massive amounts of biological waste and the resolution of environmental issues related to its storage. When fossil fuels are replaced with environmentally friendly fuels, fewer dangerous substances are released into the atmosphere. The construction of new facilities for the production of briquettes and pellets boosts employment in the agriculture sector and advances it as a whole.

Features and disadvantages of husk pellets

Based on our experience, not all pelletizers are appropriate for pelletizing sunflower husks due to their lower quality compared to sawdust, which has a higher oil content. Even though high-quality wood pellets can be produced on the pelletizer, husk pellets made from the same matrix may not have the same density and may have an uneven surface. A high compression matrix is needed for this material.

Compared to wood, pellets made from seed husks contain more ash. The majority of pellet boiler forum users are concerned about this drawback. Husk’s ash content is typically estimated to be between 1% and 3%, however some reviews claim it can reach up to 7%. Remarkably, due to variations in the mineral composition of the soil, sunflower seed husks grown on different soils can leave varying amounts of unburnable residues.

Even sunflower husk ash is not a waste product in this instance because it can be effectively applied to the soil to fertilize it. In rural areas, homeowners gather it to use for summer gardening.

Making fuel pellets out of sawdust is an economical and environmentally friendly method of heating your house. The technology involved is simple, regardless of whether you choose to produce it in-house or through a factory. Often regarded as waste, sawdust can be converted into a valuable fuel that burns cleanly and efficiently, making

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