Submitted to: Applied Engineering in Agriculture
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/16/2008
Publication Date: 9/1/2008
Publication URL: naldc.nal.usda.gov/download/23292/PDF
Citation: Mina-Boac, J., Maghirang, R.G., Casada, M. 2008. Feed Pellet and Corn Durability and Breakage During Repeated Elevator Handling. Applied Engineering in Agriculture. 24(5):637-643 Interpretive Summary: An estimated 80% of non-ruminant animal feed in the U.S. is pelleted — a form that improves the efficiency of feeding and the convenience of feed handling. Feed pellets need to be durable and of high quality to withstand the handling and transportation process after production. To evaluate breakage and durability of corn-meal-type feed pellets, the pellets were repeatedly transferred between two storage bins in the USDA-ARS, Grain Marketing and Production Research Center research elevator at Manhattan, Kansas and results were compared with that of shelled corn. The apparent size of feed pellets decreased with repeated transfers, whereas the amount of broken pellets increased, but by significantly different amounts than with shelled corn. Both feed pellets and shelled corn withstood eight repeated elevator handlings without a significant change in durability as measured by the standard tumbling box test, although the accumulated breakage of feed pellets was 50% after eight transfers as compared to 6.2% for shelled corn. Analysis of dust removed by the cyclone separators showed that these feed pellets generated less dust emissions per unit mass of pellet handled than did shelled corn. These results will be valuable for feed and grain handlers for evaluating and improving their handling and transportation procedures.
Technical Abstract: Pelleting of animal feeds is important for improved feeding efficiency and for convenience of handling. Pellet quality impacts the feeding benefits for the animals and pellet integrity during handling. To determine the effect of repeated handling on feed pellet breakage and durability, a 22.6-t (1000-bu) lot of feed pellets made from corn meal was transferred alternately between two storage bins in the USDA-ARS, Grain Marketing and Production Research Center research elevator at Manhattan, Kansas, at an average flow rate of 62.2 t/h. To compare the effect of repeated handling on feed pellets with that of corn, a lot of 25.4 t (1000-bu) of shelled corn was also tested. Samples from a diverter-type sampler were analyzed for particle size distribution (by sieving) and durability (by the tumbling box method). The apparent geometric mean diameter of pellet samples decreased with repeated transfers, whereas the mass of accumulated broken pellets increased with repeated transfers. The percentage of broken pellets increased by an average of 3.83% with each transfer from an initial value of 17.5%, which was significantly different from the values obtained from shelled corn (p>0.05) with an average increase of 0.38% per transfer. The durability index of feed pellets averaged 92.9% (standard deviation=0.6%) and did not change significantly (p>0.05) during the transfers. The durability index of shelled corn was also not significantly different. Analysis of dust removed by the cyclone separators showed that the mass of dust <0.125 mm was significantly less for feed pellets (0.337 kg/t of pellet mass) than for shelled corn (0.403 kg/t of corn mass).