Arid Zone Journal of Engineering, Technology and Environment, December, 2018; Vol. 14(4): 614-628 Copyright © Faculty of Engineering, University of Maiduguri, Maiduguri, Nigeria. Print ISSN: 1596-2490, Electronic ISSN: 2545-5818, www.azojete.com.ng 614 CONCEPTUAL DESIGN AND SIMULATION OF AFRICAN OIL BEAN SEED DEHULLER A. Fadeyibi 1* , M. G. Yisa 1 and O. S. Oladeji 1 (Department of Food and Agricultural Engineering, Kwara State University, Malete, P.M.B. 1530, Ilorin, Kwara State, Nigeria) *Corresponding Author’s Email: adeshina.fadeyibi@kwasu.edu.ng Abstract Dehulling is a unit operation preceding oil extraction of most agricultural products. While it is common to dehull the African oil bean seed manually, the mechanical operation of the process has not been reported. Thus, this study was undertaken to design and simulate African oil bean seed dehulling machine. The design was based on previous investigation of the physical and mechanical properties of the seed at 15 % moisture content (db), including average breaking force of the seed (1.12 kN). Computational fluid dynamic method was used to carry out machine simulation and the effect of time of machine operation on motor torque; angular velocity and linear displacement were investigated. The design results show that a 3 HP, single phase electric motor was required to power 25 mm shaft diameter of the machine. The simulation results show that the angular velocity was high as soon as the machine commences operation, but this progressively decreases with an increase in the time of operation. The reason for this may be due to a decrease in the viscous effect of the internal wall which causes the air stream flow to slow down with a resultant drop in the relative angular velocity to the surface. This implies that the machine is practicable with performance likely to decrease with time of machine operation. Keyword: African oil bean seed, Design, Simulation, Dehuller 1. Introduction African oil bean (Pentaclethra macrophylla) is a tropical tree belonging to the family of Leguminosae minosoadeae and is popularly grown in Nigeria. The tree grows to a height of 21 m and is well branched and forms a crown like canopy. Flowering is by cross pollination, which is normally between March and November. The flowers produced by the plant are yellow and pinkish white in color, sweet smelling and attract myriads of insects including the honeybee. The plant bears fruit in the form of green pods which slowly darken with maturity and is 0.36 to 0.46 m long and 0.05 to 0.10 m broad. Each pod contains up to 10 seeds, and the pods split open to scatter the seeds up to a distance 20 m from the tree at maturity after harvest (Akindahunsi et al., 2004). The seeds are flat in shape, hard, but smooth in texture, brown in color and about 0.06 m long, as shown Figure 1 (Adekunle et al., 2008). Also, fermented product of the seeds is good delicacy in Nigeria due to its high nutritional composition (Akindahunsi et al., 2004; Kar and Okechukwu, 1990). For instance, it is an important and cheap source of protein for people whose staple foods are deficient in protein and can be used as a flavor in soup. Figure 1: Ruptured pod and seeds of African oil bean