LIMA — Each day, Guardian Lima grinds roughly 420 acres of corn. The ethanol plant is known for its production of fuel-grade ethanol, an alternative, corn-based fuel mixed with gasoline in fuels like E15 and E85. But the plant also produces dry distiller’s grain and distiller’s corn oil, lesser known products used in animal feed, biodiesel and other oil-based products.
A single bushel of corn is turned into three gallons of ethanol, 15 pounds of distiller’s grain and one pound of distiller’s corn oil, Guardian Plant Manager Jack Wolfcale told the Lima Rotary Club on Monday.
Ethanol is a product of fermentation, Wolfcale said, during which corn is broken down into glucose and fed into yeast to ferment.
It all starts with corn: the bushels are pulverized into flour, which is then mixed with recycled water to produce enzymes. Those enzymes, Wolfcale said, are used to speed up the breakdown of carbohydrates into small enough sugars that the plant can process.
Next is the fermentation process, which takes place in giant fermenter tanks visible from the road that must be cooled year-round to keep the yeast inside from overheating the tanks.
The process is much like home brewing on an industrial scale, Wolfcale said, accelerating fermentation so that it is complete in three days rather than taking several weeks.
Once the yeast is fermented, Wolfcale said, the plant distills or separates the water from the ethanol, which is then blended with gasoline and a corrosion inhibitor to protect fuel tanks from corroding, while the grains for the distiller’s grain are separated from the ethanol and dried.
Fuel-based ethanol is often touted as a cleaner fuel alternative and a path for energy independence in the U.S.
Wolfcale said roughly 15.8 billion gallons of ethanol go into the fuel market each year, offsetting the amount of foreign oil consumed here and reducing vehicle-produced greenhouse gas emissions by 54.1 million metric tons in 2019.