Cereal Chem 39:381 - 388.  |  VIEW ARTICLE

Corn Dry-Milling: Influence of Feed Rate and Tail-Gate Loading upon Beall Degerminator Performance.

O. L. Brekke, L. A. Weinecke, and E. L. Griffin, Jr. Copyright 1962 by the American Association of Cereal Chemists, Inc. 

In degerminating corn with a No. 0 Beall degerminator in a series of short experimental tests, the germ recovery was excellent at the lowest feed rate. As the net throughput (gross less +3-1/2 mesh recycle stock) was increased from 8.4 to 17.9 bu. per hour (degerminator is rated by the manufacturer at 10 to 20 bushels hourly capacity), the germ recovery fell off sharply, then more slowly, and finally leveled off. The potential oil yield varied accordingly from 1.56 to 0.92 lb. per bu. Oil content of the -4+6 and -6+8 grit fractions increased steadily to levels more than double the initial values of 0.44 and 0.83%, respectively. The finer fractions are not analyzed for oil content. The yield of -4+6 grits rose steadily, and the -6+8 grits reached a maximum at 12 bu. per hour (i.e., about 80% of the normal feed rate) while yields of the recycle and -3- 1/2+4 mesh stocks increased in an exponential manner. The best recovery of hull and minimum amount of - 4+6 grits with attached hulls were obtained at 11-12 bu. per hour. Power requirement decreased from 0.8 to 0.6 kw.-hr. per bu. with increasing feed rate. These results were obtained with fixed degerminator settings on corn of 13% initial moisture content tempered for 3 to 4 hours to 23% moisture. While the net hourly throughput decreased 20% with the degerminator tailgate loading almost doubled, a smaller yield of -4+6 grits and a better yield of -6+8 grits, germ, and hull were obtained. Reductions were noted simultaneously in attached hulls and in oil content of the -4+6 and -6+8 grits. However, the germ recovery and oil content of the coarse grits were not equal to those obtained at the lowest feed rate. Improved germ and oil recovery and grits of lower oil content are obtainable by operating Beall degerminators at much less than usual throughput rates (i.e., ca. 0.8 of manufacturer's minimum rating or 0.3 of present commercial rates) and with a minimum to moderate tail-gate loading.