Compaction and relaxation characteristics of single compacts produced from distiller’s spent grain Original Research Article

Compaction and relaxation characteristics of densified distiller’s spent grain compacts produced at different levels of compressive pressure (60.3–135.7 MPa), initial moisture content (15%, 20% and 25% wb) and soluble content (15% and 30%) were analyzed during the study. The compaction levels used in this study caused up to a 4% wb reduction in the moisture of compacts in comparison to their initial moisture. The density of compacts was analyzed to determine the compaction characteristics of distiller’s spent grain using Jones model. Analysis of the Jones model showed that there was a significant (P = 0.004) decrease in compressibility with an increase in soluble content from 0% to 30%. The distiller’s spent grain compacts were subjected to relaxation tests and the relaxation data obtained were normalized and analyzed to determine the asymptotic modulus (EA) of the compacts. The asymptotic modulus was used as a measure of rigidity of the compacts. Distiller’s spent grain compact produced with a compressive force of 135.7 MPa and initial moisture of 25% wb possessed the highest EA value.