To determine whether the process developed using the
synthetic high FFA feedstock could be extended to actual
feedstocks, methyl esters of yellow and brown grease were
prepared. The yellow grease was obtained from the Simonsen
rendering plant in Quimby, Iowa. Rendering plant greases
typically have a FFA level between 5% and 25% depending
on the time of year. The specific fat analyzed for this project
had an acid value of 25.15 mg KOH/g, which corresponds to
a FFA level of about 12%. The fatty acid distribution of the
yellow grease is shown in table 4 compared to soybean oil.
As would be expected from yellow grease derived primarily
from animal fat, the fat was solid at room temperature.