77 Functional performance of a vertical-shaft centrifugal palm nut cracker M.C. Ndukwu 1 , S.N. Asoegwu 2 1 Department of Agricultural Engineering, Michael Okpara University of Agriculture, Umuahia, Nigeria 2 Department of Agricultural Engineering, Federal University of Technology, Owerri, Nigeria Abstract Ndukwu M.C., Asoegwu S.N, 2010. Functional performance of a vertical-shaft centrifugal palm nut cracker. Res. Agr. Eng., 56: 77–83. A vertical-shaft centrifugal palm nut cracker was presented and evaluated. he cracker eiciency and kernel breakage ratio are some of the most important parameters for evaluating the cracker performance. From the result of this work, the two parameters are function of cracking speed, moisture content and feed rate. he result showed that for the lowest speed of 1,650 r/min, and the highest feed rate of 880 kg/h and for all moisture contents, the cracking eiciency was not up to 65%, therefore the eiciency increases with an increase in machine speed and a decrease in feed rate. he kernel breakage ratio ranged from 0–0.18 (0–18%) for all feed rates and moisture contents. It increased with moisture content and cracking speed, but decreased with feed rate. All the parameters determined have a linear relationship with moisture content. Keywords: kernel; cracking eiciency; feed rate; throughput capacity; shaft speed; kernel breakage Res. Agr. Eng. Vol. 56, 2010, No. 2: 77–83 he oil palm (Elaeis guineensis Jacq.) is a great economic asset. It is acclaimed to be the richest vegetable oil plant (Kheiri 1985). According to this author many products can be derived from the oil palm; this includes palm oil, palm kernel oil, palm kernel cake, ibre, palm wine, fatty alcohol, broom, and wood plank. Harvested palm bunches undergo processing stages of sterilization, stripping, diges- tion, and palm oil extraction. Palm nuts and ibres are left as residues. he nuts are dried and cracked into palm kernel and shell. It is separated into palm kernel oil (PKO), palm kernel meal (PKM), and water (Akinoso et al. 2009). he world production of oil palm products has always been impossible to access accurately due to the recorded quantity produced in grooves and outlaying groups as semi-wild palm, for domestic use and for sale. Estimate made by the FAO (1996) suggested a rise from 3.6 billion kg of palm kernel and 11.3 billion kg of palm oil in 1989–1991 to 5.08 billion kg of palm kernel and 17.04 billion kg palm oil in 1996–1997. However, according to the FAO (1996) the palm kernel pro- duction potential of several countries was not fully exploited, which may be attributed to poor extrac- tion methods. However global output forecast for oil palm production according to FAO (2005, 2006) will reach 42 billion kg. According to Anonymous (2004–2006) the world palm oil production during 2005–2006 stood at 39.86 billion kg of which 4.36 billion kg is palm kernel oil. he rate of vegetable oil consumption is increasing compared to animal fat due to its health implication (Akinoso et al. 2009). he industry is challenged by demands for high quality products at reduced prices. Importance of oil crops as a vital part of the world’s food supply was evidenced in world agricultural trade statistics.