Author
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Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/13/2016 Publication Date: 4/26/2016 Citation: Butts, C.L., Sorensen, R.B., Lamb, M.C. 2016. Evaluation of a small-scale peanut sheller. Peanut Science. 43(1):67-73. Interpretive Summary: Commercial peanut shelling equipment is designed to shell peanuts at a rate of 20 metric tons/hr. Smaller shelling equipment intended for evaluating samples has a throughput ranging from 6 to 50 kg/h. There is a need for intermediately sized peanut shelling equipment for small peanut processors, particularly in developing countries. A prototype peanut sheller was fabricated with a target shelling capacity of 500 to 1000 kg/h to meet the needs of a peanut processor in Haiti making Ready to Use Therapeutic Food (RUTF) from peanut paste. The sheller consists of four major components: 1)the surge hopper, 2)the 3-stage shelling chamber, 3) the hull aspiration system, and 4)shaker/sizing screens. The purpose of these tests were to: 1) determine the proper damper position on the aspiration system to separate the peanut hulls from the kernels, 2)determine the optimum shelling cylinder speed (rpm), and 3) determine the shelling capacity (kg/h). The air velocity in the aspiration chamber ranged from 4 m/s with the damper fully closed to 13 m/s with the damper fully open. Approximately 65% of the hulls were removed at the lowest air velocity. The maximum amount of hulls (> 95%) were removed when the aspiration air velocity reached 9 m/s. Increasing the air velocity increased the amount of peanut kernels that were aspirated into the waste stream with the hulls. At the maximum air velocity of 13 m/s, approximately 0.6% of the peanut kernels were aspirated into the waste stream. The maximum hull removal with minimal kernel loss occurred with an aspiration air velocity of 9 m/s and the damper positioned approximately 50% open. The shelling cylinder speed (rpm) was varied from 215 to 340 rpm. The first stage had the highest shelling capacity ranging from 823 to 1048 kg/h depending on the cylinder speed. Shelling capacity was 957 kg/h using a cylinder speed of 215 rpm. The maximum shelling capacity of 1048 kg/h occurred when the cylinder was turning at 248 rpm. The shelling capacity decreased as the cylinder speed increased above 248 rpm. There were no statistically significant differences in the percent split kernels due to sheller speed, but the minimum number of split kernels (18%) occurred when the sheller speed was 300 rpm. Based on these tests, this sheller can be used to shell peanuts at an average rate of 1 metric ton/hr and should be operated at 250 rpm and the damper for the hull aspiration system should be positioned 50% open. Technical Abstract: Commercial peanut shelling equipment is designed to shell peanuts at a rate of 20 metric tons/hr. Smaller shelling equipment intended for evaluating samples has a throughput ranging from 6 to 50 kg/h. There is a need for intermediately sized peanut shelling equipment for small peanut processors, particularly in developing countries. A prototype peanut sheller was fabricated with a target shelling capacity of 500 to 1000 kg/h to meet the needs of a peanut processor in Haiti making Ready to Use Therapeutic Food (RUTF) from peanut paste. The sheller consists of four major components: 1)the surge hopper, 2)the 3-stage shelling chamber, 3) the hull aspiration system, and 4)shaker/sizing screens. The purpose of these tests were to: 1) determine the proper damper position on the aspiration system to separate the peanut hulls from the kernels, 2)determine the optimum shelling cylinder speed (rpm), and 3) determine the shelling capacity (kg/h). The air velocity in the aspiration chamber ranged from 4 m/s with the damper fully closed to 13 m/s with the damper fully open. Approximately 65% of the hulls were removed at the lowest air velocity. The maximum amount of hulls (> 95%) were removed when the aspiration air velocity reached 9 m/s. Increasing the air velocity increased the amount of peanut kernels that were aspirated into the waste stream with the hulls. At the maximum air velocity of 13 m/s, approximately 0.6% of the peanut kernels were aspirated into the waste stream. The maximum hull removal with minimal kernel loss occurred with an aspiration air velocity of 9 m/s and the damper positioned approximately 50% open. The shelling cylinder speed (rpm) was varied from 215 to 340 rpm. The first stage had the highest shelling capacity ranging from 823 to 1048 kg/h depending on the cylinder speed. Shelling capacity was 957 kg/h using a cylinder speed of 215 rpm. The maximum shelling capacity of 1048 kg/h occurred when the cylinder was turning at 248 rpm. The shelling capacity decreased as the cylinder speed increased above 248 rpm. There were no statistically significant differences in the percent split kernels due to sheller speed, but the minimum number of split kernels (18%) occurred when the sheller speed was 300 rpm. Based on these tests, this sheller can be used to shell peanuts at an average rate of 1 metric ton/hr and should be operated at 250 rpm and the damper for the hull aspiration system should be positioned 50% open. |
