25 Izgrev Str., Dunavtsi 6145, Bulgaria,
tel.: +359 4348 2424; mob: +359 888 567549 Е-mail: office@tronpellets.eu
BIO-FUELS AND THE USE OF WOOD PELLETS
Wood pellets are pure, neutral in terms of carbon dioxide emissions and convenient fuel which is produced primarily from sawdust and wood waste molded under high pressure without glue or other additives. Wood pellets are cylinder-shaped, usually 10-30 mm long with diameter 6-10 mm. This makes wood pellets highly standardized and compact material allowing for lower cost of transport; in addition, wood pellets enable to automate the exploitation of heat and electrical power installations as easily in one-family houses as in large-scale energy plants. Expanding their market share at a fast pace, wood pellets has become a significant resource for increasing the utilization of biomass in Europe and other regions of the world. They are also the perfect means of utilizing local resources because, in material aspect, they are giving their share to environment protection and control of climate changes. European Union has set a series of aims intended to increase the share of recycled energy sources capable of generating heat and electrical power. Biomass has a strategic importance for the realization of these aims; in particular, wood pellets are the key technology having some specific advantages. Wood pellets are cheaper and more compact for transportation purposes as compared to other forms of biomass, while on the other hand the high percentage of their standardization provides for very low emissions from combustion, even at smallest applications. Wood pellets are also very convenient fuel for end users – they are equally fit for delivery by tank trucks or in bags and are convenient for use in automatic feeding systems, because they are easy for handling and time-saving just like the systems working with gas and liquid fuels.
Pellet heaters are used for handling larger loads, which may be either houses or industrial buildings, and should be connected to a heating system. Their rated capacity ranges from 5 to 2.500 kW at 85-95 % energy conversion efficiency). To compare, a residence with 80-90 m2 or 200-225 m3 heatable area will need minimum 4.5 - 5 kWt installed capacity to compensate for the demanded heat load. The heater is fully automated and equipped with a special pellet burner. The installation may be complemented with small fuel tank and special purpose hopper to store larger amount of pellets (for instance the amount needed for the entire heating season), which can be built on site.
It is possible to redesign an existing conventional heater (functioning on liquid fuel, gas) by replacing its burner with a pellet and/or wood splinters (chips) burner. In this case, the cost of investment will be much lower, because the required heating installation and infrastructure are already on place, ready to be used. The price of pellet heaters varies depending on the type and capacity, but considering the existing ratio of the prices of different fuels at the moment (for example, provided all conditions are the same, pellet heating will be 40% cheaper than heating by liquid fuel, and at the same time it has all the advantages such as automated fuel feeding and small amount of ash/waste from combustion), the difference in purchase prices of liquid fuel heaters and pellet heaters will be neutralized within a year.
