Abstract (EN):
Many European countries are developing the use of pellets or wood briquettes for the
supplying of local energy. Many industries are being forced to replace fossil fuels by
biomass because of its neutrality in relation to CO2 emissions, thus creating an
interesting market for pellets. In Portugal, the most common undergrowth includes:
esteva (Cistus Ladanifer), tojo (Ulex Europaeus), giesta (Sarothamus Scoparius), feto
(Pteridium aquilium) and silva (Rubus ulmifolius). These undergrowth specimen are
attractive due to the large volume available, but are not usually used for making pellets.
It is possible to prevent large fires cleaning the forests, but this is an expensive task that
could be compensated if the undergrowth can have some commercial value. The aim of
this work is to obtain pellets with standard properties and evaluate the parameters that
can qualify the performance of these pellets: moisture content, particle size distribution,
high heating value, height of flame and burning time, pressure and temperature of the
pelletizing process and mechanical durability. The results showed that the apparent
density varies around 1260 kg/m3. The moisture content of different pellet varied
between 2.79 and 7.46%, ash content was less than 3%, the calorific value is between
16-18kJ/kg, the durability results respect the values recommended by standards. After
ignition the flame increases to an average height of 25 mm. The total burning time was in
all cases dominated by the cinder combustion without visible flame and the total complete
burning time varied between 400 and 600 s.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
6