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Ethanol From Corn Process. Dry Mill Ethanol Process Lina M Rueda. 1 bushel of corn (56 lbs). Ethanol (17.6 lbs) + DDGS (17 lbs) + Heat (7450 BTU) + CO2 (18.4 lbs). Milling. Starch (32 lbs). Liquefaction Saccharification. Fermentable sugar (36 lbs).
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Ethanol From Corn Process Dry Mill Ethanol Process Lina M Rueda
1 bushel of corn (56 lbs) Ethanol (17.6 lbs) + DDGS (17 lbs) + Heat (7450 BTU) + CO2 (18.4 lbs) Milling Starch (32 lbs) Liquefaction Saccharification Fermentable sugar (36 lbs) Fermentation Recovery Dryhouse The Distillery Flow Diagram: From Corn to Ethanol Plus Co-products 3
Fermentation Fundamentals • Key Ingredients • Starch (sugar source) • Enzymes (breakdown of starches) • Yeast (conversion of sugar to ethanol) • Key Process Components • Enzyme addition • Yeast propagation • Fermentation cycle • Cooling system 4
Process Description • Milling • Cooking and mixing • Milled corn and cook water • a-Amylase to break down long polymer chains (starch), reduce solids • Solubilization of sugars • Release of bound sugars: starch is bound to protein and fiber which is released during cooking • Gelatinization: absorb water so enzymes can react with molecules • Liquefaction • Using a-Amylase to break down starches to shorter chain molecules • Saccharification and Fermentation • Batch processs (~ 50-60 hours) • Exothermic • Glucoamylase is used to break down short chained molecules to glucose • Yeast is added to convert glucose to ethanol 5
8 8 Methanator Water Balance Milling Process Water Beer Feed Slurry Tank Liquefaction Backset 6
8 Fermentation Yeast Propagation Fermenter Beer Feed Enzymes Slurry Tank Liquefaction Backset 7
Process Description • Distillation • Separate Ethanol from non-fermentable components • Dehydration • Azeotropic Distillation • Molecular Sieves • Non-Fermentables • Centrifugation • Evaporation • Drying 8
Distillation Vaporizer Temperature Rectifier Reflux Sieve Feed Sieve Back Pressure Beer Feed Evap. Steam Steam Flow 9
Dryer, Evaporator and TO Wet Cake Pad Whole Stillage Centrifuge Feed Dryers Thin Stillage Syrup Tank Steam Flow Evaporators 10
Control Strategy $ costs Ethanol Plant-Wide Optimizer Energy, feedstock, Product Values Slurry/Waterbalance APC Dryer Evap TOAPC & Distill/Sieve APC Fermentation APC Plant and constraint Measurements (CV) Mv setpoints 11