Sawdust briquettes: how to make “euro-wood” for fuel assemblies with your own hands
Firewood that would burn for a long time, give a lot of heat and little ash, do not throw sparks and soot - the dream of the owner of a country house with stove heating or a fireplace. It is these properties that sawdust briquettes possess, which you can not only purchase, but also make with your own hands. You should familiarize yourself with the manufacturing process. It is so?
We will talk about how to make fuel briquettes for use in heating a country house or cottage. In our article, we describe in detail the technology for the production of logs from pressed sawdust. Independent home masters with us will find brief instructions on how to assemble a press machine.
The content of the article:
Advantages of Sawdust Logs
In favor of briquettes pressed from sawdust, the following arguments can be given:
- Long burning - 4 hours.
- Minimal smoke generation.
- Environmental friendliness. The feedstock is natural materials, so the beds can be fertilized with ash.
- High energy efficiency. Far exceeds the energy capabilities of firewood, comparable only with high-quality coal.
- Constant combustion temperature.
- Profitability. The cost of 1 ton of such fuel will be cheaper than the corresponding amount of firewood or coal.
- The possibility of self-manufacturing.
Deficiencies are also present. The main one is the fear of moisture. You can’t store them in the open air, because they quickly absorb moisture, therefore, they will burn badly. Therefore, for storage it is necessary to allocate a dry room.
Any significant mechanical effects on sawdust briquettes are contraindicated. If you buy special equipment for their manufacture, the cost will be high and not always justified.
It is advantageous to establish handicraft production if sawdust is free, and existing equipment can be used as an installation.
Types of fuel briquettes
Briquettes are divided into types depending on their shape. The main types of products that can be found on the market are:
- RUF. These are pressed rectangles measuring 15 x 9.5 x 6.5 cm. They are made from sawdust of natural wood with the addition of special components.
- Nestro. Visually, these are cylinders with a diameter of 6 to 9 cm and a length of 5 to 35 cm, with no holes. The material for production is pressed wood pulp. It is dried, placed in a loading container, then fed through a screw for pressing. Dispensers distribute the mass under pressure forms.
- Pini kay. In shape, these are polyhedrons with the number of faces from 4 to 6. In the production process, they are subjected to high temperature processing and pressing under high, up to 1100 bar, pressure. As a result, combustion efficiency, moisture resistance, and density increase.
The chemical composition and heat transfer of all these species pressed sawdust identical, they differ only in density. This fuel is not characterized by sparks flying in different directions. High density and low hygroscopicity allow you to store this fuel in a small pantry next to the stove.
If for the formation of briquettes there is the necessary raw materials, they can be made independently.
Equipment for the production of briquettes
In industrial conditions, the grinding of wood waste is performed on special mechanisms - crushers. Such an important part of the technological process as drying is performed using drying machines, which are of two types - drum and aerodynamic.
The products are formed on hydraulic press. With a minimum force of 30 MPa, it compacts the mass. At the same time, no raw materials need to be added to the feed, since Under these conditions, wood glue - lignin - is released due to compression and high temperature.
Any form of briquettes can be obtained on a shock-mechanical press, but their density is not very high.
There is another method for obtaining "Eurodro" - extrusion. It is based on the fact that with a force of about 40 MPa, the mass is pushed through the calibrated holes by means of a screw, thus forming products in the form of cylinders or hexagons. At the exit, they are cut with special knives.
The performance of screw extruders is higher than that of mechanical or hydraulic presses.
Buying such plants for the manufacture of their own hands and the procurement of fuel briquettes is irrational, for this there are other options.
The main supplier of sawdust is a sawmill. It doesn’t matter what kind of wood, the main criterion is humidity. It should not go beyond 12%. In the total mass, the amount of spoiled wood should not exceed 5%.
This process does not differ in great complexity and, in general terms, consists of five stages:
- Raw material cleaning. It is necessary to remove dirt, excess impurities.
- Shredding. The size of the sawdust matters - a maximum of 0.6 cm.
After the first preparatory stage, the mass is mixed with dry, powdered clay, a proportion of 10: 1. Then, adding a little water, begin to mix. It should be noted that the density of the mixture should be medium. The ability to maintain its shape, the duration of drying, and the final density of products depends on this indicator.
The next step is to ship the resulting mixture to the briquette of the briquetting equipment. Then the actual pressing in the molds. After all, it remains only to dry the finished briquettes well. Cardboard soaked in water is sometimes added to clay in a mixture. In this case, the combustibility of the fuel increases.
At home, you can make equipment in three versions:
- with hydraulic drive;
- with a manual drive;
- with jacks.
Manual adaptation is the simplest. It can be attached to the wall. The frame for it is made of a steel pipe or corner by welding.
We must not miss the moment that when the sawdust is large, they must be crushed before pressing. The simplest cutter is also suitable for this, but it is better to mechanize this process. Well, if the house has a machine for grinding grass, it will cope with the crushing of sawdust.
Some craftsmen fit outdated washing machines for this purpose. To do this, the activator is supplemented with knives.
Manual Drive Machine
The press for the production of sawdust briquettes at home is fixed on the wall with dowels. In the lower part of the structure, a stationary form is fixed.
Its geometry can be any. To control the mechanism, a lever is needed, therefore, a hinge is mounted on the upper crossbar, by means of which a pipe segment or a long metal stud is fixed.
The fixed form will serve as a matrix, and the punch is attached to the lever. It is important to correctly calculate the length of the pipe so that the punch fits freely into the die.
The second version of the hand press is the floor mechanism. Its design is identical to the wall fixture, the only difference is that the welded bed, to which the main parts are attached, is installed on a flat horizontal surface.
Another type of manual equipment is a screw press. It is very easy to use. The lower part is a perforated molding container placed under the bed.
When tightening the screw, create the pressure necessary for pressing. The performance of such a device is very low. It takes a lot of time to load, tighten the screw, remove the finished product. Lever models have more potential.
Improved homemade option
Manual equipment can be improved by supplementing it with a jack or hydraulic press. The shape is made square or round. The base is welded from the channel. Racks - corner 100 x 100.
Round shapes are made from pipes with thick walls. The matrix is perforated to leave the water released during compression. For the extraction of finished products, the bottom is made removable.
It is possible for this purpose to install a spring inside the matrix by attaching it to the bottom, but then it must be welded tightly. A disk is attached to the spring. When the product is formed, it is compressed, and when the rod makes a reverse stroke, it straightens and pushes the finished briquette out of the mold with a disk.
The stem is made of a pipe with a diameter of about 3 cm. A punch, which enters the matrix with a small gap, is fastened to one end by welding. The opposite end of the rod is fixed to the hydraulic jack or press.
Before loading the raw materials, it must be mixed well. This requires a special container. Make it out of sheet steel or fit a drum from an old washing machine and install it on racks.Mixing can be done with a mixer or in a concrete mixer.
From the drum, the pulp enters for pressing into molds on a tray made of sheet steel. It is best to dry briquettes in the oven, but it is also possible in the sun. The main thing is that the humidity is minimal. Only a dry type of fuel will give such an amount of thermal energy, which is enough to heat the premises.
Stationary briquetting press
For the manufacture of such a press, a 2.5 kW engine will be required if work is to be done from a 220 V network. If a three-phase voltage is supplied, a 9 kW motor will do. In addition, you need a gearbox, shaft, bearing, screw, heating elements, relays for temperature control.
The engine, gearbox and other components are mounted on a welded frame from a corner. It is installed on racks made of pipes. The screw in this design consists of the spirit of the parts. One of the bottom transforms the sawdust into a loading tank, the second - acts as a punch. The role of the matrix is performed by the pipe.
Before starting the press, the pipe is heated by heating elements up to 260⁰. The heating is controlled by a relay. The briquette seal adjusts the square welded to the pipe. As a design flaw, large heat losses to the environment can be noted. But at the same time, the quality of briquettes is significantly increased.
How to calculate the need for fuel briquettes?
Having decided to transfer the heating of your home to sawdust briquettes, it is better to immediately calculate how much of them will be needed to last for the entire period. Here you need to take into account the temperature that must be maintained, the area of the room, the thickness of the walls and other factors.
Ecological fuel quality also plays an important role. The heat transfer of 1 kg of high-quality briquettes can reach up to 4, 4 kW. From products manufactured at home to use in brick kilns or metal bath units, such a result will not be.
Suppose a house with an area of 100 m² is well insulated, the heating period lasts 190 days, the coefficient of operation of the boiler is 0.7. Then 100 x 190 x 24 x 0.7 x 70 = 22 344 kW. If we take into account that the furnace efficiency is 86%, the heat transfer will decrease to 3.9 kW. Investigator, you need a stock of briquettes 22 344: 3.9 = 5.7 tons.
Conclusions and useful video on the topic
Video # 1. An interesting version of a homemade machine for the production of briquettes from sawdust:
Video # 2. Preparation of the working mixture for briquettes:
Video # 3. Burning fuel briquettes in a boiler:
Self-made briquettes are within the power of everyone. This requires both physical and material costs, plus time. It is also necessary to take into account the moment that it is unlikely to be at home to achieve high quality at the level of Eurodroves.
Nevertheless, in the presence of raw materials, briquettes can be made, at least not for a full heating cycle, but for igniting firewood.
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