Development and Performance Evaluation of a Motorized Jatropha curcas Seed Cracker-Winnower

摘要

Jatropha curcas L. is a multipurpose drought-resistant plant with numerous attributes and considerable potentials. The oil content of the kernels in the seeds is very important to the biodiesel industry. Manual cracking of the seeds for the oil extraction is labour intensive and time consuming. The objective of the study was to develop a cracker with winnower for cracking Jatropha curcas seeds and to evaluate it. Physical properties of Jatropha curcas seeds and kernels were determined for development of the cracker. The cracker was developed using locally available materials. It has four main components being the hopper, cracking, blower and power transmission units. The hopper unit holds and introduces the seeds into the cracking unit which consists of a pneumatic tyre and a concave sieve made from a perforated metal sheet. The seeds are cracked by a combination of friction and compression forces of the rotating tyre on the seeds working against the stationary concave sieve. Air from the blower separates the kernels and the husks through the kernel and husk spouts, respectively. The cracker was evaluated at cracking drum speeds of 140, 150, 160, 170 and 180 rpm and feed gate openings of 32, 48 and 64 mm. At the recommended 140 rpm speed and 48 mm feed gate opening, the cracker had a capacity of 1037.90 kg/h, blower loss of 2.76%, cleaning efficiency of 88.65%, cracking efficiency of 96.68% and machine efficiency of 90.84%.