Pellets are cheap solid fuel and are made by pressing dry crushed wood waste into cylindrical granules. The main advantage of pellet heating systems is the automatic fuel supply.
Fuel pellets also have many other positive characteristics that set them apart from other types of fuel. For example, pellets are high-quality, are environmentally-friendly, biological fuel. The pellets manufacture is one of the priority areas for many companies that are connected with fuel production. Wood pellets are very profitable, convenient, and safe which makes them the best option to solve heating problems. This type of fuel is affordable. The pellets price is less than the electricity, gas, diesel fuel prices. Moreover, pellets create very little waste during combustion. What’s more, the efficiency of boilers running on pellets is 90-95%.
ADVANTAGES OF PELLETS
Let’s consider the main advantages of pellets:
- Greenhouse gas reduction. When fuel pellets are burned the same amount of carbon dioxide is emitted into the air as the tree has absorbed during growth, the so-called closed carbon cycle.
2) The length of wood pellets is about 20-50 mm, the diameter is approximately 4-10 mm. It makes the process of packing more convenient.
3) The heating value of wood pellets is 5 kWh per kilogram.
4) It should be noted, the energy content of one kilogram of wood pellets is equal to 500 ml of liquid fuel (diesel fuel).
5) The ash mass is only 0.4% of the fuel mass. It means that there will be only four liters of ash after burning one cubic meter of pellets. Therefore, frequent cleaning of boilers is not required.
6) To produce the pellets, it is needed to spend only 3% of the amount of energy that pellets generate during combustion. For comparison, it is needed about 10% of energy to produce oil fuel and 60% for electricity.
All these mentioned advantages make pellets an extremely forward-looking fuel. The price of pellets does not depend on world oil price fluctuations and remains constant.
Wood pellets also have a relatively high bulk density (also called apparent density or volumetric density). It makes pellet transportation and pellet storage more optimal than transportation and storage of traditional types of fuel. The production of pellets is gaining momentum every year. Factories that are engaged in the pellet production pack them in convenient packaging. It makes loading and unloading easier and more efficient. Pellets can be stored in bulk or bags.
Pellets are packed only in two types of containers:
- Big Bag (polypropylene containers);
- plastic bags.
Big Bag is polypropylene containers that are recognized as universal packaging worldwide. Big Bag is used to pack the pellets for industrial heating boilers. Plastic bags are usually good to pack the pellets for home-usage.
Pellets can be stored in any dry room. They are not easy to ignite and do not pose a significant fire hazard. Such fuels as fuel oil, gas, diesel fuel, and coal are easily flammable. Also, they all have harmful odors. If used incorrectly, they pollute the atmosphere. Therefore, they require careful handling while used. Pellets are much safer for people who use them as fuel. Most importantly, the safety of a pellet boiler is much higher than the safety of similar gas or diesel boiler.
There is a significant difference between wholesale and retail pellet prices. Of course, it is much more profitable to buy pellets in bulk especially when preparing for the heating season in winter.
The price of pellets can be checked on the Internet at any time. Also, there is a special chat on web sites where you can ask any questions to the online assistant. The online assistant will tell clients how to choose the right fuel that can heat your home at the lowest cost.
PELLET MANUFACTURING PROCESS
The pressing process consists of forcing small sawdust through a press matrix. First of all, sawdust is poured onto the press matrix. Then special rollers begin to roll over the matrix and press the sawdust into the holes in the matrix. The number of rollers may differ. It depends on press productivity.
The rollers are set with a certain gap. Let’s look at the principle of pressing:
1) the first roller rolls the sawdust;
2) the second roller presses it down;
3) the third roller just presses it;
4) the fourth one pushes sawdust into the holes:
5) the fifth roller cleans up the press matrix.
It boils down to this: the gap between the second roller and matrix is less than the gap between the first roller and matrix. The gap between the third roller and matrix is less than the gap between the second roller and matrix and so on. The pressing process is a cyclical one and, therefore, is repeated in a certain interval of time.
Only the dried wood chips can be taken for pressing. The moisture of wood chips varies from 6% to 15%. The certain value is selected individually for each type of raw material and press. But anyway, the dried wood chips are used only what means that it is harder than the raw chips. That is why the rollers and the press matrix wear out very quickly and they should be looked after.
Pellets can be used both in furnaces and in solid fuel boilersю. They are poured onto the furnace grates manually. Where else can pellets be used? Let’s find out about it together.
Did you know that pellets can be used during camping? Let’s consider pellet use in field conditions. If you carefully unpack the pellets, you can put them in a smaller bag and take them on hikes. When you need to start a fire pit, you certainly can use pellets. It is very convenient and practical to use them in field conditions. Moreover, pellets will burn for one and a half to two hours.
Also, pellets can be used in a completely different area of life. Any guesses? They become part of the pet toilet. Yes, pellets are used as toilet filler. For example, cats, various rodents like chinchillas, hamsters, and other pets simply really like to relieve themselves inside the toilets filled with pellets.
Why are pets so crazy about it? Let’s look at some benefits of this filler. Pellets as filler:
1) create no dust;
2) prevent the growth of bacteria;
3) absorb the nasty smell;
4) perfectly absorb moisture;
5) smell as a pleasant pine scent;
6) do not stick to paws and wool;
7) are natural and environmentally-friendly;
8) cause no allergies;
9) do not decompose;
10) are safe when ingested in a pet’s stomach;
11) are cost-effective.
Would you be surprised to find out that wood pellets are used in renovation work? I think after you learned that wood pellets are used as fillers for pet toilets, you will be not much surprised to hear it. So, when there is some repair work, you can see wood pellets used as an absorbent material. There is no fundamental difference between wood shavings and pellets. They both can be used as an absorbent material and also for cleaning various technical fluids such as engine oil.
There are a lot of myths and legends associated with the pellet quality. The reason is the lack of information about pellets. Let’s summarize all knowledge related to this topic. We will talk about how to tell a good quality wood pellet from a bad one. Clients often ask this very question that is why we will consider it.
The best option to check pellet quality is to burn one pellet bag in a boiler, stove, or furnace. Before carrying out this pellet quality test, it is recommended to use pellets that were released by one manufacturer and preferably at the same time from the same materials.
The quality of pellets is determined according to the following criteria:
- visual assessment of pellets;
- how easy pellets crumble;
- the pellet diameter;
- pellet color;
- the solubility of pellets.
How can we visually evaluate the pellets? If the pellet surface is smooth and shining and there are no cracks on them, it is pellets of good quality. The smooth and shining surface indicates that the pellets were pelletized at the correct temperature. It also means that lignin, which is present in the wood, has glued the pellets as needed.
Another way to evaluate the pellet quality is to determine how the pellets crumble.
If the pellets are too soft, they will crumble during loading into the bunker and during subsequent feeding into the combustion zone. Therefore, solid pellets are more preferable to buy. The abrasiveness of the pellets, also called mechanical resistance, can be measured by special instruments.
Let’s look at the technology of these instruments. A weight of 100 kg is applied to the samples within a minute. Then the pellets are blown with compressed air. Then the pellet quality is measured by the number of particles of a certain size. If there are few particles, it confirms high quality of pellets. If there are many particles, the quality of the pellets leaves much to be desired.
It is important to note that there always a small number of particles and dust after unloading. So you can determine the number of overloads of these pellets by the number of particles and dust in the package. Moreover, it is usually less dust and particles among pellets that were packed in bags and more “waste” among pellets that were shipped in bulk.
What can we say by pellet diameter? Some people think that the pellet diameter should be 6 mm, some people believe that the perfect value of diameter is 8mm. However, they all are right because the pellet diameter depends on the equipment that they are made of.
Does pellet color mean something? Yes! The most common pellets are white-yellow, which are made from waste remaining. This waste is usually obtained from furniture production. If the pellet contains brown blotches, this indicates that bark has been added to the raw material.
What do pellets smell like? The pellets usually have the smell of the wood they are made from. There may be no smell at all. By the way, if the pellets are stored for a long time in a damp room, they will absorb all odors.
However, neither the color nor the smell can indicate pellet quality. We only can speak about the raw materials which the pellets were made from, as well as about the conditions for its storage.
What can we learn about pellets by their solubility? When the pellets are put into water, they turn into a wet mass after a certain amount of time. Otherwise, some chemical was used as a binder.
Also, there is a simple test to check pellet quality. You need to take a glass of water and throw a few pellets into it. They have to drown immediately because their density is 1.1 g/cm3 while water density is about 1 g/cm3. Besides, if pellets retain their shape for approximately 20 minutes, it indicates the high quality of their pressing.
So, pellet production determines the pellet quality. That is why you’d better buy pellets by yourself to check their surface, solubility, smell, and even diameter.
So to sum it up, the pellets constitute an alternative fuel that can be used for heating country houses and cottages or in field conditions. This fuel is very convenient in use and meets all environmental requirements. The pellets can also be used as absorbent material during different repair work or filler for pet toilets.