THE PELLETS - A NEW, ECONOMICAL AND ECOLOGICAL COMBUSTION MATERIAL Technical Report

Radu SEBASTIAN
Eng. - Director SEBA Industrial S.R.L. Bucuresti
Address: Bd. Iuliu Maniu nr. 562, Sector 6, 061129 Bucuresti
Tel. +4021 3183669. Fax. +4021 3183675. E-mail: seba-industrial@seba.ro

Pellets are a new combustion material, which meets the actual requirements of using "clean" and regenerative energy and which represents the alternative for domestic and industrial heating and also the cleanest one. In Romania, in the conditions of aligning the costs of the classical combustibles to the European ones, this alternative will become soon the more economic and comfortable in the same time.

By definition, the pellet is a small briquette obtained by pressing the wood dust resulted from logs cutting and from the primary and secondary processing of wood and also from the wood flakes resulted from the wood waste and tree falls or other vegetal materials.

The history of the pellets production is as follows:
- 1970 - the first pellets production unit is built in Brownsville, USA.
- 1983 - the first residential thermal station which uses pellets as combustible is sold in USA.
- 1990 - the industrial manufacturing of pellets as combustibles begins in Sweden.
- 1996 - there were more than 20 manufacturers of thermal stations and more than 80 pellets producers.

More than one million tons of pellets are heating houses from North America.
- 1997 - there were more than 500 000 thermal power stations using pellets in North America.

The wooden pellets production and the rapid development of the market for this product is due to the following reasons:
- it is an efficient way of using the local resources of the community in order to produce thermal energy at low costs;
- pellets are easy to use in automatic feeding installations unlike the classical briquettes with big sizes, which generally are used to replace the firewood;
- it doesn't release noxa through burning process and it doesn't influence the global warming of the planet, releasing as much carbon dioxide as the vegetation consumes.

The fabrication process for these small briquettes is the extrusion in special equipment, and it doesn't need additives and binding materials because of the resins contained by wood as basic raw material. The main component equipment of an installation which produces pellets are:
- raw material warehouse
- wood primary reduction equipment
- transportation and feeding system
- sawdust dryer
- hammer mill for grinding
- system for fiber conditioning
- extruder for pellets
- pellets cooler
- pellets packing machine
- conditioning areas
- finished product warehouse.

According to the statistical data published in 2004, the utilization of pellets for the big consumers in Europe is as follows:

In Germany, the sales movement in the last 3 years for stoves and boilers using wooden pellets is as follows:
- 2003 - 11000 units;
- 2004 - 23000 units;
- 2005 - 38000 units.

The main characteristics of the wooden pellets are:
- Size: diameter 6 - 8mm, maximum length is five times the diameter.
-Calorific power: 16,9 -18MJ/kg ( 4,7 - 5 Kwh/kg )
- Moisture content: 8 - 12%
- Ash content: 0,5%
- Raw material: wood sawdust, wood flakes
- Density: 650 - 700kg / cbm
- Deposit area: 1,5cbm / ton
- Equivalence:1000 liters fuel = 2,1 tons pellets; 1 ton fuel = 2,5 tons pellets.

In the countries from Western Europe there are pellets norms in force. Thus, in Germany the pellets must be produced according to DIN 51731 which specify the following characteristics:
- Diameters - there are 5 classes from 4 to 10mm
- Length - smaller or equal to 50mm
- Density - 1 - 1.4 g/cm3.
- Moisture content - smaller or equal to 12%
- Ash content - smaller or equal to 1.5%
- Calorific power 17.5 - 19.5MJ/kg
- Sulphur content - smaller than 0.08%
- Nitrogène content - smaller than 0.3%
- Chlorine content - smaller than 0.03%.

Speaking about noxa emission, the studies show that the pellet has the lower emission comparing it with the emissions from other combustibles such as firewood, sawdust or oil.

We are presenting you below the carbon monoxide emissions for the thermal power stations with the power between 15 and 50kW:
- firewood ……………….. 310mg/Nmc
- sawdust …………….…. 120mg/Nmc
- pellet ……………………103mg/Nmc

The emission of particles experimentally determined for the same types of thermal power stations, are as follows:
- firewood …………………...23mg/Nmc
- sawdust ……………………34mg/Nmc
- pellet ……………………….19mg/Nmc

Pellets cost
There is a study made in 2003 and published in January 2004 by a group of researchers from the research institutes for secondary energy resources named: WIP - Munich; ETA - Renewable Energies; EUBIA; CARTIF; CRES. The study was done on a group of 5 countries where the pellets are produced, namely Austria, France, Germany, Portugal and Switzerland. The five countries have produced in 2004 a total amount of approx. 128 millions tons of pellets. The production cost to produce 1 ton of pellets in the studied countries is as follows:

COSTURI / COSTS	MINIM Euro	MAXIM Euro	MEDIU/ AVERAGE Euro
Materie prima / Raw material	25	50	37.5
Paletare / Palleting	20	30	25
Amortizari si diverse / Ammortissement and other	49	84	66.5
COSTURI TOTALE / TOTAL COSTS	94	164	129

There are no statistical data for Romania, because the pellets production is just at the beginning, at this time being only two companies with an important pellets production and they don't make public the fabrication cost. Anyhow, if we consider that in January 2006 the companies in Romania were selling one ton of pellets with 100 - 120 euro, we can figure that the production cost is lower that the minimum one in Europe. A relevant index of the fabrication cost in Romania is the cost of one ton of sawdust in 2006, which vary between 1 and 3 euro representing a 10 times lower price that in European countries. In the first 8 months of year 2006 one ton of pellets has been exported by the Romanian companies at EXW prices of 120 euro in January 2006, going to 180 euro in August 2006, and the production costs hadn't increased so much, for sure. A theoretical calculus of the production costs in Romania based on the actual prices for electric energy, transport and wood dust goes to a medium pellets cost of 70 euro/ton which can vary depending on the fabrication line capacity and the distance to the raw material source. The forecasts show that even the price will be 10 times more than the acquisition cost of the sawdust, the pellets fabrication cost Romania can not be more than 80 euro/ton in 2007. The conclusion is that pellets business is a profitable one.

Speaking about the raw materials for pellets, we must say that it is not limited only to wood, the research work from the more developed countries went in finding plants having a great regenerative power after genetic mutations. Thus, in Sweden there is already a land of approx. 50.000 ha which is cultivated with a plant named "energetic willow" producing in the first year approx. 10 tons of vegetal material at one hectare and beginning with the second year the production goes to 40 tons/ha. In Hungary have been cultivated 2000 hectares with this plant, and the production was higher than in Sweden, because of o higher temperature and it went to 60 tons / ha. The European Community has released already a legislation for this, and countries belonging to the community, including Hungary, have adopted this legislation, through which the state finance the economical agents who want to cultivate these energetic plants. In Romania there are economical agents who have license agreements to cultivate bulbs of these energetic plants in nurseries, and they wait the moment when legislation will come into force. The solution of using these plants to obtain energy has the great advantage that the raw material is a regenerative one and not limited like the actual fuels.