PARTICULATE MATTER EMISSIONS FROM COMBUSTION OF DIFFERENT TYPES OF WOOD PELLET

摘要

The aim of this work is to investigate the emissions of particulate matter (PM_(10)) from the combustion of specific types of wood pellets used for domestic heating. Wood pellets as: mix "pine-beech-oak", "olive pellets", mix "spruce-pine-oak", "pellets from the olive core" and "100 % spruce" used recently for domestic heating were tested with respect to their PM_(10) emissions regarding concentration and composition. A combusting- sampling device was developed in order to burn the pellets and collect directly their PM_(10) emissions in a filter holder system. The water content, calorific value, ash content, C, H, N and S were determined according to the standard ELOT EN 303.05. Average PM_(10) emissions from the investigated wood pellets ranged from about 80-190 mg/m~3, exceeding some of them the maximum permitted emission limits of particles of 150 mg/m~3. Around 40% of total particle mass account for total organic carbon and 35 % for elemental carbon, while non inorganic carbon was found for all types of pellets. On average around 0.5 % of PM_(10) emissions was consisted of heavy metals and water soluble ions. Metals like: Fe, Mg, Zn, Al, Ba, Cu, Cd were determined by inductively coupled plasma -optical emission spectrometry (ICP-OES) and K, Ca, Na were determined by atomic absorption spectrometry (AAS) and their percentage of PM_(10) emissions was around 0.3%. Water soluble ions like: Cl~-, NO_3~- PO_4~(3-) SO_4~(2-), Br~-were determined by ion chromatography and their percentage was 0.2 %. The results are in accordance with previous studies using similar types of pellets as concerns the fuel's chemical characteristics. Pellets originated from olive trees were found to emit the lowest PM_(10) emissions that are not exceed the permissible limit values so are considered healthiest and suitable for domestic heating reasons.