Closed-steam-loop drying system clears up stack exhaust, cuts fuel costs
To beat EPA air emissions limits and cut energy and maintenance costs, an ethanol producer replaces an aging, inefficient rotary drum dryer with a closed-steam-loop drying system for processing spent-grain by-product.
Each year, the Pekin, Ill., plant of MGP Ingredients of Illinois (MGPI) turns out more than 70,000,000 gallons of ethanol, an increasingly popular clean-burning alternative to oil-based fuels. Annually, the plant uses 70,000 tons of wheat-processing residue combined with about 670,000 tons of ground corn to produce the ethanol and other alcohol products. But producing ethanol leaves behind large quantities of a by-product called whole stillage, a soup of grain solids and solubles. To recover some value from the whole stillage, the plant further processes it to produce feed additives for cattle, hogs, and chickens.