DEVELOPMENT OF A LABORATORY MODEL MECHANICAL

Abstract

In the laboratory, small quantities of freshly expelled oil are often required for on-the-spot analysis. This small quantity of oil can be obtained from oil bearing seeds or nuts like palm kernel at an affordable price using a model mechanical rig coupled to a Universal Testing Machine (UTM) or any suitable press. In this study, a model mechanical expression rig with a heater band was designed fabricated and tested using ground palm kernel. In the design, the size of the cylinder (diameter and length), the size of the piston, the maximum pressure desired, the maximum load available from the universal Testing Machine, the maximum cross-head travel from the load frame of the UTM, and the temperature controller were considered and determined. A travel or loading speed of 2.5mm/min suitable for agricultural materials was adopted during the testing of the model.

Results from the tests carried out showed that an average value of 38.32% oil yield corresponding to 76.63% oil recovery was obtained for pre-heated grounded palm kernel sample. while oil yield of 20.41% corresponding to 40.83% oil recovery efficiency was obtained for grounded palm  kernel samples not heated before oil expression. These values compares favourably with values obtained from literature. Statistical analysis using t-test also revealed that there was significant difference between the values of oil yield and oil recovery efficiency respectively obtained from the pre-heated and the non pre-heated samples at 5% confidence level.

Quality evaluation of the crude palm kernel oil expressed using the model showed that the free fatty acids, iodine value and the solid fat content values of the oil obtained from pre-heated samples were lower than that obtained from samples not pre-heated, implying that oil expressed from pre-heated palm kernels is of better quality when compared to the oil obtained from palm kernel not pre-heated. Also the characterization values obtained from the oil expressed using the model compares favourably to values obtained from literature.