When planning a heating system in a private house, it must be considered that not every building can connect a central gas supply, and electric heating is often prohibitively expensive. In such cases, pellets are the best alternative.
So, what is it? Pellets are the most environmentally friendly fuel that is known to man now. During their manufacture and use, no harmful substances are emitted into the atmosphere at all. Pellets are small, compressed granules in the form of a cylinder. For their manufacture, the most common sawdust and other wood waste are used, although now there are more and more different alternative materials. You need a wood pellet mill on a large or small scale depending on your production requirement.
Like any other business, pellet production begins with equipment. In this article, we will take a closer look at their varieties and features, the specifics of production, and give advice on choosing.
Before wood or other waste is turned into pellets, the raw material must go through the first and very important stage in the production of pellets – the preparation of raw materials. To do this, at the beginning, with the help of special equipment, the material is crushed. The need for pre-crushing exists most often only in cases where dimensional material is taken as raw material. The result of this stage are very small particles, the size of which does not exceed 4 ml.
Next, the raw materials are dried in a special chamber. The temperature inside reaches 400 degrees, while the humidity does not exceed 10%. So that the raw material does not lose its ability to stick together, it is very important not to over dry it during the process. Otherwise, it will not work to compress all this into granules.
In the production of pellet fuel, aspiration is important – the process of cleaning the air from dust. The main purpose of aspiration is to eliminate the spread of harmful emissions during production into the airspace. Such a device is more often needed in light and heavy industries, the technological process in which occurs with the release of harmful substances. The main difference between such ventilation is the large angle of inclination of the air ducts and the high speed of the air flow.
After air purification, all raw materials enter a special bunker. In its shape, it resembles a cylinder. In this chamber, at the very bottom, there is a continuously rotating mechanism, the operation of which prevents the mass from caking. Thus, the crushed sawdust evenly enters the granulator for the next stage – pressing.
Granulation or shaping takes place by a special machine called a granulator. It is the main element of the entire production line.
In production conditions where there is a need for equipment with high productivity, a press with a cylindrical die is often used. This is a metal perforated ring, inside which several rollers go. With the help of a special screw, the raw material is fed directly to them, after which the sawdust is pressed by rollers into the holes of the matrix. At the exit, the resulting “sausages” are cut with a special knife.
In order to form pellets, a prerequisite is the presence of high temperatures. At the outlet of the press, their temperature varies from 70 to 110 °C. Therefore, there is a need for cooling or conditioning to ambient temperature. For this, special blocks for cooling are used.
The completion of the pellet production process is the packaging of the finished fuel. The final product is sorted into so-called big bags, with a capacity of one kg, or special bags (tare for the consumer), capable of holding from 5 to 15 kg. In the future, until they are used for their intended purpose, the pellets are stored in well-ventilated and dry rooms. In addition, it is important to place the bags on pallets.
To select equipment, you need to understand the scope of work that is expected to be performed. Large-sized machines are quite expensive and always turn out to be costly in terms of the amount of electricity consumed. If you need to produce a small volume of pellets, then small and low-productivity machines will be more profitable. We recommend that you look at existing pellet manufacturers and conduct competitive intelligence.