Investigation into the Energy Demand for Palm Nut Cracking Using the Static Impact Method

Investigation into the energy demand for cracking of palm nuts using static impact method was carried out. A nut cracking energy equipment was designed and constructed for the analysis. Fresh palm kernel nuts already dried to a moisture content of 10.42%wb ready for cracking were obtained from an oil mill and characterized into five categories based on their nominal diameter as follows d<12mm; 12mm≤d<15mm; 15mm≤d<17mm; 17mm≤d<19mm; 19mm≤d20mm. The nuts were subjected to cracking using the equipment developed and visual observation was used to assess the level of cracking as follows; completely cracked (CC), completely cracked with slight damage (CCD), cracked without nut separation (CWS), unable to crack (UC) and smashed (SM). The results show that efficiency for complete cracking of nuts without defects increased with increase in drop height to a peak (80 – 100%) and then decreased. Statistical analysis show that the cracking energy determined and cracking percentage have high linear correlation at (0.91, 0.82, 0.94, 0.81 and 0.74) and corresponding high coefficient of determination (0.836, 0.671, 0.889, 0.659, 0.5407) for the various size ranges with their t test showing high significance at 5% level of probability. It was also observed that cracking energies of 0.514; 0.709; 0.904; 1.294 and 1.787 J respectively were adequate to sufficiently crack palm nuts of the five size ranges respectively and release whole kernel. The results suggests the need to grade palm kernel nuts before cracking and the design of a nut cracker with a grading component before cracking to actualize minimal breakage of kernels.