Title: Unit 4 Readings and Lecture
Course: BFM 201 Ethanol Production > Section: BFM 201 Ethanol Production

Unit 4 Readings and Lecture

To Do:
Read Textbook: Ethanol Process Fundamentals
Chapter 3 Milling & Mixing, pages 3.8 - 3.11 AND Chapter 4 Cooking & Liquefaction, pages 4.1 – 4.4
This unit shows us the milling and cooking processes of ethanol production from corn. After the corn is ground to a fine meal it is mixed with water in the slurry tank. The water used is backset stillage (from the distillation system) and recycled water. The goal of the facility is to have zero discharge of water. The starch granules are impervious to water or enzymes so the corn meal is cooked at a temperature high enough to break down the granular structure of the starch and cause it to gelatinize (swell up). The granular structures swell up and with agitation break apart exposing more surface area for the enzyme alpha amylase to convert the starch to dextrin. It is important to understand that there are four key factors for success of the cook process. Monitor closely the temperature, pH, agitation and dosage. The temperature must be high enough to gelatinize so the starch granules absorb water. The high temperatures also help control bacteria.  However, the temperature cannot be so high that the enzyme will not function. The pH must be monitored closely such that it stays in the range that the enzymes like for maximum activity. The agitation is important to help break apart the swelled starch granules and to keep the mash flow able in the system. The correct dosage of enzyme to add is important because enzymes are expensive and the high heat will put to much stress on them and they will unravel. Only 1/3 of the enzyme needed will be added in the slurry tank. The rest will be added during the liquefaction stage.
References:

Chapter 3 and Chapter 4. (2006). In Ethanol process fundamentals: An introduction to ethanol processing. Granite Falls, MN: Minnesota Energy Enterprise Center.

Jacques, Kathryn Ann., T. P. Lyons, and D. R. Kelsall. "Chapter 2." The Alcohol Textbook: A Reference for the Beverage, Fuel and Industrial Alcohol Industries. Nottingham: Nottingham UP, 2003. N. pag. Print.