It is a tendency in the whole civilized world for heating the traditional fuels to be replaced by renewed power sources, which are more available and more ecological like wood and other plant materials, processed as biofuels. In contrast to the usual wood material for burning, for the production of wood briquettes or peat briquettes are used contemporary technologies, based on breaking to pieces of the material up to homogeneous mass and its pressing at high pressure, as a result of which there are obtained granules (pellets), which are called biofuel. The process is called pelleting.
The heating granules, popular as pellets, are a biofuel, obtained from wood products, peat and agricultural wastes. They are small cylindrical granules with high density and low moisture, which guarantees their high efficiency at burning. Their small sizes and their regular form are facilitation at feed in the heating bodies and at storage.
They are characterized by low content of ash (below 3%) and high calorie level. They are produced through compressing of wood wastes. Initially the by-products, obtained after processing of wood – wood chips, dry sticks, wood dust from turning – are ground into a dense homogenous mass. This mass passes through a press with high pressure, at the end of which there is put a matrix with the respective opening – usually 6 mm, although there are and bigger ones. The high pressure of the press increases the temperature significantly and besides it is drying additionally the wood mass it creates natural glue in the lignin fibres, which preserves the integrity of the pellets after there comes cooling.
The qualitative wood pellets have low content of dust and ash, low water content (less than 10 percents), they sink in water, they do not decompose at pressure by hand. There is not a visible difference between the pellets of different types of wood, since they all pass through grounding and turn into a homogenous wood mass. The biofuel of this type cannot contain residia from recycled wood or chemical pollutants. Melamine particles, painted wood, covered with resin boards are unsuitable for production of wood pellets, since at their burning are released noxious chemical substances or are observed diversions from the norms for burning of pellets.
The power content of the wood pellets is around 5500 kcal/kg – one and a half time more than the normal wood. The pellets for usage of life are distinguished with their light cream-colour and sweetish scent. Besides as a fuel they can be used as an absorber in the chemical production, as a pad for cat toilets or for covering of cattle-sheds and stables.
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Wood pellets for heating
The wood pellets are with cylindrical form and with size 6 mm in diameter and up to 30 mm length. At the pressing is used the substance lignin (natural glue, which is contained in the wood) without agglutinant additions. The pellets of wood mass are an ecologicaland very perspective fuel, which is used for creation of heat. The usage of boilers and stoves with wood pellets is a real alternative of the familiar to us heating – the fir.
The heating with wood pellets suggests number of advantages before the conventional fossil fuels for heating:
The caloricity of the wood pellets is 4300 – 5100 kcal/kg. The Efficiency of the heating systems is 85% – 95% (Efficiency of fireplaces with wood is 70%) and because of their qualities the pellets burn almost completely. Thus the time between two consecutive refueling of the fireplace is between two and five days. For comparison the caloricity of the fir is 3440 kcal/kg.
Low content of ash
A big advantage of the wood pellets is in low content of ash after their burning in boilers for pellets or in fireplaces and stoves. The opportunity the ash to be used as compost in the garden, at which the soil restores its equilibrium, is also important.
Comfort comparable with the heating with gas
At burning the wood pellets do not release black smoke, which makes them ideal for fireplaces with a glass opening. The usage of pellets provides comfort comparable with the heating with gas, because of the almost complete burning (around 98,5%), besides the boilers and the stoves for heating with pellets almost do not produce any creosote. This also allows the instalment of boilers and stoves with pellets with a direct air vent… without a chimney!
Low content of water
The pellets are exceptionally compact and they have low content of moisture (within the boundaries 8 % – 10 %), which allows them to burn with very high efficiency.
A cheaper source of power
One ton of wood pellets has heating value of 6 cubic meters wood material and it is contained easily in one third of the space! This makes it possible easily to be stored fuel for the whole season. An important factor is and the relative stability of the prices of the pellets in comparison with the prices of the fossil power sources.
Automatization of the process of burning at heating with pellets
The pellets can burn as in ordinary stoves and fireplaces for solid fuel, as well as in special boilers for pellets with high efficiency and big degree of automatization, approaching to the boilers with gas and electricity. Boilers with pellets dose on their own the necessary for them quantity of pellets for burning.
Protection of the environment
It is of great importance the decrease of the dependency on petroleum, natural gas and propane – all non-renewable fossil fuels, used for heating. The wood pellets are renewable fuel, which is obtained of permanent sources – the pure wood mass. Replacement of the fossil fuels as petroleum, natural gas or propane by heating with pellets decreases the emissions of greenhouse gases, as this way it facilitates for decrease of the change of the climate and protection of the environment.
Do you know for the pellets that …
– The pellets are one of the most used biomasses. They are obtained through mechanical processing, which puts the wood chips, obtained by cutting, under high pressure.
– The pellets are produced on the base of wood chips, residia from processing of wood, suitably dried and pressed under high pressure thus so to be obtained small cylinders with different size. Thanks to the binding possibility of the lignin, a natural substance, which is found in the firewood, it is not necessary the adding of any type of addition, in order to be obtained a natural fuel, ecological and with high efficiency.
– They are perfect for supply of devices for heating , the pellets are highly calorie (5kW) , clean and not polluting. They burn completely with minimum residual ashes (0,4%/1kg.), which can be used as a precious material for fertilizing of the garden. Having in mind the pressure in the production stage, the power density of the pellet is approximately double to the one of the wood.
– The pellets supply fireplaces with water and air jacket, as well as boilers for central heating with big capacity.
WHAT ARE THE WOOD PELLETS
The wood pellets are with a cylindrical form, with diameter 6-10mm and with length between 10 and 30 mm. They are produced of sawdust and wastes, pressed under high pressure, without a glue or other additions. As a result of this the product is with a small volume, which allows lowering of the expenses for transport. They can be transported in bags or directly with tanks and they are appropriate for usage at automatically feeding systems, which makes them suitable for processing and they save time.
Types of pellets
The pellets as per their nature actually are a biofuel, obtained from wood products, peat and agricultural wastes. They are small cylindrical granules with high compactness and low moisture, which guarantees their high efficiency at burning. Their small sizes and their regular form are facilitation at feed in the heating bodies and at storage.
They are produced through compressing of wood wastes. Initially the by-products, obtained after processing of wood – wood chips, dry sticks, wood dust of turning – are ground into compact homogenous mass. This mass passes through a press with high pressure, at the end of which is put a matrix with the respective opening – usually 6 mm, although there are and bigger ones. The high pressure of the press increases significantly the temperature and except that it dries additionally the wood mass, creates a natural glue in the lignin fibres, which preserves the integrity of the pellets after cooling occurs.
The qualitative wood pellets have low content of ash and dust, low water content (less than 10 percents), they sink in water, they do not decompose at pressure by hand. There is not a visible difference between the pellets from the different type of wood, since they all pass through grinding and they transform into homogenous wood mass.
The biofuel of this type cannot contain residua of recycled wood or chemical pollutants. Melamine particles, painted wood, covered with resin boards are unsuitable for production of wood pellets, since at their burning there are released noxious chemical substances or there are observed diversions from the norms for burning of pellets.
The power content of the wood pellets is around 5500 kcal/kg – one and a half time more than the ordinary wood. The pellets for everyday usage are also distinguished by their light cream colour and sweetish scent. Besides as a fuel, they can be used as an absorber in the chemical production, as a pad for cat toilets or for covering of cattle-sheds and stables.
Pellets of chicken excrements
One of the latest technologies for production of pellets includes the usage of chicken excrements as a basic raw material. The granules of this type are an excellent substitute of the wood pellets. They can be used and as improvers of the soil and fodder. They contain important microelements as cobalt, copper, manganese, zinc and iron. They are rich in carotin, riboflavin and of mineral substances like nitrogen, potassium and phosphorus. In its capacity as a fodder are special protein additions, which can be used up to 40% from the total quantity of the concentrated fodder. As per chemical content they are close to the sunflower groats, out of which also are produced fuel pellets.
The process of production of this type of pellets is similar to the production of wood coals. They are obtained through slow heating of the biomass in conditions of deficiency of oxygen. The process is known as „scorching”. When the wood is heated up to 160 degrees, it dries, but it preserves its ability to absorb water. If the heating continues, the wood starts to darken, there are released acetic acid and phenol. In such conditions it darkens, it changes its chemical properties, it increases its hydrophobia, it starts to crumble. The elimination of the acetic acid from the wood is of use for the pellet boiler – there are slowed down the corrosion processes in its metal parts. If the heating of the wood continues, the carbon dioxide in it strongly decreases, but the content of methane, hydrogen, hydrocarbon and carbon is increased.
The process of scorching is carried out at temperatures between 200 and 270 degrees as per centigrade. The raw material, processes in this way, has significant advantages to the ordinary wood.
The most essential advantage of this process is that through it practically every wood can be transformed into a uniform raw material for preparing of pellets. The produced by it granules are with saturated black colour, they have high power efficiency and are suitable for transportation. The burning of these pellets is done practically without no smoke.
There are two methods of scorching :
- permanent – the raw material is scorched in process of transporting over an elevator. In this case it is obligatory to be preliminary dried and the wood to have uniform shape. The scorching is done through a direct contact of the wood with the surface of the heating elements.
- The method of the immovable layer – it is carried out with the assistance of an inert gas, which temperature is changed during the process. Thus the scorching is carried out through a convection, but the processes of drying and scorchingshould be divided in time. The obtained raw material is put into a granulator for production of pellets. They have characteristics, similar to the coals, but they are fed in the zone of burning with much fewer losses and practically they do not contain ash.
Pellets of peat
The technology for production of peat pellets almost does not distinguish from the one for the wood pellets. The qualities of the peat as a fuel are known for centuries. Nowadays this exceptionally ecological renewable fuel is one of the basic raw materials for production of pellets. For the first time peat pellets were produced in 1947, when their usage for everyday heating started.
After the production the peat is purified from admixtures it is drieduntil its humidity reaches 15 percents. Subsequently it is broken to pieces and is pressed in granules. Since it contains in itself natural sticking substances, it is not necessary to be added additional ingredients. Before it is fed in the machine for pressing the peat is processed by dry steam, which activates the sticking substances.
The peat pellets have a little bit higher content of ash than the wood pellets. At the burning of one ton peat pellets they release heat power, equal to the heat power of a ton and a half wood, almost 500 cubic meter gas, a half ton diesel and around 700 litres of fuel oil.
The pellets of peat are used in the production as industrial fuel. They are used rarer in the everyday heating of homes, villas and offices, because of the higher content of ash. Besides the peat pellets find application in the gardening as a soil dresser. Their high hydroscopic capacity and environmental friendliness make them a beneficial element at the breeding of domestic animals and aquarium fish. The fruit and vegetablesare preserved in peat pellets for continued transportation.
Pellets of straw and peculiarities at their burning.
On the market frequently are met pellets, produced of straw, sunflower and rice husks. These materials have very low temperature of melting of the ash, which automatically takes out of operation the adjusted boilers and stoves, intended for wood or coals. There should not be burnt pellets of straw or sunflower in not well adjusted boilers.
If you have not rendered an account of this information preliminarily, this may lead to losses, and to refuse you to use ecofuel in the future, despite its indisputable qualities.
If you have decided yet to use the produced of straw, sunflower and rice husks, the best variant is they to be used in specially adjusted stoves and boilers. The best choice are these produced in Denmark, since the Scandinavian country is a world leader in usage of the straw as a fuel. In these installations is introduced a contemporary technology of burning – a moving two-wheel grid, which maintains the regime of burning, so that the ash not to succeed to melt itself. This makes the Danish stoves irreplaceable for pellets of straw.
Confirmed facts for the pellets
- The pellets are considered for a completely ecologically clean fuel.
- The carbon emissions from the burning of the wood granules do not change the content of С02 in the atmosphere. The companies, which use heating granules do not need buying of quotas for greenhouse gases.
- At burning the pellets release exactly as much as С02, as there is obtained at the decay of the wood. This increases their ecological value.
- The pellets release exceptionally little ash – around 1 – 2 percents. Practically there is not sulphur in their content.
- The ashes can be preserved in proximity of residential premises, since they are biologically not active after the passed thermal processing. There are not contained spores, which can provoke an allergic reaction.
What else can pellets be used for
Because of their specific qualities the pellets have and other applications.
One of the conveniences of the pellets is that they can be used as filler for the toilets of the domestic animals. The cat toilets are a mass product, which requires a frequent change of the filling, because of the high degree of contamination. The same is referred and to the litter of the cages of hamsters, guinea-pigs, even birds. The standardly used until now chips do not provide sufficiently good level of hygiene. In contrast to them the pellets, because of their high hygroscopic capacity, possess number of advantages. In the first place, they impede the typical scent of cat toilet. They absorb liquids three times more than their weight and they remain dry long time. They do not disperse dust or small particles. The animals feel comfortable, because on their fur do not stick irritating chips. The pellets are hypoallergenic and sufficiently ecological, in order not to create a problem at accidental getting into the stomach of the animal. If there are used pellets, the change of the filler of the cage or the toilet is not daily. The pellets do not allow to be spread and developed bacteria, they do not decay and do not decompose. Besides they are the most economical choice.
Often the pellets are used as an absorbent in different cases – in car repair shops for absorption of liquids, at water-main repairs as a basic hygroscopic material and so on.
The pellets are a wonderful choice also for barbeque.One of their basic advantages is the fact that they are cheaper than the charcoal. Besides the cancerogenic effect of the coals is completely eliminated at the processed pellets. For their kindling is necessary ordinary paper, without additional kindling liquid or spirit. The pellets burn without smoke so there shall not be contamination over the meat or the barbeque itself. The little released ash facilitates the cleaning.