ENERGY BALANCE AND EFFICIENCY IN WOOD SAWDUST BRIQUETTES PRODUCTION

The industrial wood briquette making process is an alternative to add value to forestry waste and involves the compaction of sawdust at high pressure and temperature. The present study was performed in an industry in the state of Goias, Brazil. All kinds of energy involved in the wood briquette manufacturing process were qualified and quantified, in all stages of the process. The methodology used was based on Cotrim (1992), Silva (2001), (BEN, 2007), Inconprera (2008) and NBR 8633. The total energy demand to produce one ton of Pinus wood briquettes using sawdust at 43.8% moisture was 435 kWh. When producing the same amount of briquettes at 11% humidity, this value fell to 101.66 kWh per ton. Thus, drying process of sawdust consumes 76.63% of all the energy used for manufacturing. The amount of energy required for the production of 1 ton of briquettes corresponds to 10.8% (wet sawdust) and 4.37% (dry sawdust) of the energy contained in this one ton of briquettes. Keywords: Wood densification; industry of briquette; energy.