Performance of Equipment for In-field Peanut Shelling

Authors: Butts, Christopher - Chris; Sorensen, Ronald - Ron; Nuti, Russell; Lamb, Marshall

Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: 7/11/2009
Publication Date: 7/11/2009
Citation: Butts, C.L., Sorensen, R.B., Nuti, R.C., Lamb, M.C. 2009. Performance of Equipment for In-field Peanut Shelling. Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE Paper No. 095838)

Interpretive Summary: Peanuts can potentially produce in excess of 100 gallon of peanut oil per acre for use in the production of biodiesel. However, producing, harvesting, and processing peanuts in the conventional manner can cost the equivalent of $6.00 per gallon with about 1/3 of that cost incurred to harvest, dry, and shell the peanuts. A conventional peanut combine was modified to harvest and shell peanuts that had been allowed to completely dry in the windrow. Tests were conducted to compare the amount of peanut kernels harvested and shelled using a conventional peanut combine, the modified peanut combine, and a grain combine. The modified peanut combine harvested, shelled, and captured an average of 93% of the peanut kernels harvested using a conventional peanut combine. The grain combine only captured about 62% of the peanuts. The modified peanut combine shelled nearly all of the peanuts it harvested with very few remaining unshelled. These tests showed that peanuts could remain in the windrow until completely dry, then harvested and shelled. This would reduce the post harvest processing costs in preparation of producing biodiesel from peanuts from about $2.00 to about $0.50 per gallon of biodiesel.

Technical Abstract: Drying, cleaning, and shelling peanuts represents approximately one-third of the costs included in growing, harvesting, and processing peanuts for the edible market. These processes are cost-prohibitive when producing peanuts for biodiesel. Shelling peanuts during harvest would significantly reduce production costs. A conventional two-row peanut combine normally used to thresh windrowed peanuts was modified to shell the peanuts as they were harvested. Peanuts were dug, windrowed, and allowed to partially dry in the windrow. They were then harvested using the modified peanut harvester and a conventional grain combine. Conventional peanut harvest was approximated by harvesting with the shelling grates removed from the modified peanut harvester. Total peanut kernels harvested, foreign material, and shelling efficiency were compared among the three harvesting techniques. The peanut combine with the shelling grates successfully captured 93% of the peanut kernels harvested conventionally. The grain combine captured only 62% of the peanut kernels. Both the grain combine and the modified peanut harvester shelled in excess of 93% of the peanuts harvested. Peanuts harvested with the grain combine had 30% foreign material compared to 11% harvested with the peanut combine with or without the shelling grates.