Study on Energy Requirement of Wood Chip Compaction

In order to utilize waste products such as sawdust and chips in the wood industry, pellets are made using compaction pressures in the range of 100 MPa or higher. During the compaction process, the density and the modulus of elasticity of the material rapidly increase. Wood materials generally show non-linear viscoelasticplastic behavior and, therefore, the pressure-deformation relationship is dependent on the loading velocity and on the time during which the material is subjected to constant deformation or load. The energy requirement of pellet production depends on many influencing factors and in such cases the use of dimensionless numbers in the form of similarity equation facilitates the processing of experimental results and the obtained similarity relationship has a more general validity for the users. Various fractions of different wood species were used in these experiments, and the pressure, pellet diameter, temperature were also varied. The proposed similarity equation shows a good correlation with the experimental results.