Two-Step Liquefaction Process for Corn Dry Milling
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Solution Overview
Problem
Current dry milling processes for alcohol production face inefficiencies in liquefying starch and releasing oil from corn components, resulting in lower alcohol and oil yields due to the hardness of germ and grit particles protected by protein cell walls, and incomplete separation of solids and liquids.
Innovation Solution
A two-step liquefaction process using high and low Balling (Be) liquid media, combined with a novel design of a three/four section paddle screen for high-rate replacement washing, and a power-saving nozzle centrifuge to break down and separate germ and grit particles, releasing starch and oil, and producing pure fiber for secondary alcohol production or animal feed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single-step liquefaction process is used in dry milling, then the process is simple and fast, but starch and oil extraction efficiency is low due to incomplete breakdown of germ and grit particles protected by protein cell walls
Solution Approach 1:
The liquefaction process is divided into two distinct steps: first liquefaction (30-60 minutes) and second liquefaction (1-3 hours). This segmentation allows the first step to handle easily accessible starch while the second step focuses on breaking down protected starch and oil in germ and grit particles, thereby increasing overall alcohol and oil yield without requiring complete process redesign
Solution Approach 2:
The first liquefaction step performs preliminary breakdown of accessible starch before the second step addresses the more difficult protected starch. This preliminary action prepares the material for more effective secondary processing, allowing the second liquefaction to focus specifically on breaking down protein cell wall protections
2Productivity
If traditional oil recovery systems are used, then the system is simple, but oil recovery efficiency is low with less than 50% of corn oil being recovered
Solution Approach 1:
The second liquefaction step performs preliminary breakdown of germ and grit particles to release trapped oil before the oil recovery process. This preliminary action makes oil accessible to traditional recovery systems, increasing recovery efficiency from less than 50% to over 75% without requiring complex new equipment
Solution Approach 2:
The patent changes the liquefaction parameters (time, temperature, enzyme dosage) in the second step to optimize starch and oil release from germ particles. These parameter changes enhance the effectiveness of subsequent oil recovery operations using existing equipment
3Productivity
If germ particles are not broken up in hammer mill, then the milling process is efficient and fast, but germ particles remain intact protecting starch and oil from liquefaction
Solution Approach 1:
The liquefaction process is segmented into two steps with different time allocations: first liquefaction (30-60 minutes) for accessible starch and second liquefaction (1-3 hours) for protected starch in germ particles. This segmentation efficiently utilizes time by addressing different starch populations in sequence rather than requiring extended single-step processing
Solution Approach 2:
The two-step liquefaction process maintains continuous useful action by immediately following the first liquefaction with the second liquefaction step. This continuous approach ensures that as soon as accessible starch is liquefied, the process transitions to breaking down protected starch, maximizing utilization of processing time
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach increases alcohol yield by up to 3% and oil yield by 75% of the corn's oil, producing pure fiber with reduced protein, oil, and starch content, enhancing fermenter capacity and efficiency while reducing energy consumption.
Implementation Method 1
Corn flour is mixed with cook water and a backset stream from a backend (e.g., after fermentation) to a slurry tank at a Step 102 to liquefy the starch by GA enzyme at a temperature of 190 to 200 F
Implementation Method 2
The mash from liquefication tank at the Step 103 goes through heat exchanger to cool off
Implementation Method 3
The whole stillage from bottom of the distillation column is sent to a whole stillage solid/liquid separation centrifuge (decanter) at a Step 106 to separate the solid (DDG) from liquid (thin stillage)
Implementation Method 4
The thin stillage from a decanter centrifuge as an overflow stream is sent to an evaporator at a Step 107 to boil off water and to be concentrated to about 35% of DS (dry material) syrup
Implementation Method 5
In the fermenter at the Step 104, the liquefied starch is converted to glucose then to alcohol by a simultaneous saccharification and fermentation
Data Source
AI summary
The present disclosure provides a two-step liquefication (e.g., using a high (>23 Be) and a low Be (<5 Be) liquid media) process in a dry milling process/plant. The dry milling process comprises liquifying starch from milled corns making a liquefied starch slurry in a first liquefication tank having a slurry >23 Be, performing a first solid/liquid separation using a first paddle screen after the liquifying starch, soaking, cooking, or degrading protein in a second liquefication tank with a slurry <5 Be, and performing a second solid/liquid separation using a second paddle screen after the soaking, cooking, or degrading protein in a second liquefication tank.