Counter Current Wash for Reducing Unfermentable Solids in Corn Milling
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Solution Overview
Problem
The corn dry milling process for producing biofuels and biochemicals faces inefficiencies due to high unfermentable solids content in the protein portion, which inhibits fermentation and reduces corn starch availability, leading to decreased throughput and protein yield.
Innovation Solution
Implementing a counter current wash system at the back end of the process to separate and reduce unfermentable solids in the protein portion, utilizing a series of centrifuges and washes to enhance separation and recycling of centrate back into the process, thereby increasing protein purity and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the protein portion is separated from stillage using conventional decanter centrifuge, then the protein is recovered for high protein corn meal production, but unfermentable solids remain in the protein portion which inhibits fermentation and reduces throughput
Solution Approach 1:
The process segments the stillage separation into multiple stages: first separating insoluble solids (wet cake) from liquid stillage, then separating the protein portion from water-soluble solids portion. This multi-stage segmentation allows each separation step to target specific components, improving protein purity while managing unfermentable solids effectively.
Solution Approach 2:
The invention extracts and removes unfermentable solids from the protein portion through the counter current wash system. By introducing wash water that flows counter to the protein stream, unfermentable solids are washed out and separated, leaving a cleaner protein portion suitable for fermentation without compromising throughput.
2Ease of repair
If unfermentable solids are present in the recycled centrate, then the centrate can be reused as backset in the front end process, but fermentation is inhibited and corn starch solids are decreased
Solution Approach 1:
The counter current wash system performs preliminary cleaning of the centrate before it is recycled as backset. By washing out unfermentable solids in advance, the system ensures that the recycled centrate does not contain inhibitors that would affect fermentation performance, thus maintaining both recyclability and reliability.
Solution Approach 2:
The system implements a feedback loop where the washed centrate is recycled back to the front end process. The counter current wash continuously removes unfermentable solids from the recycling stream, ensuring that the feedback loop maintains fermentation performance while enabling continuous reuse of the centrate.
3Manufacturing precision
If a counter current wash system is implemented to reduce unfermentable solids, then protein purity and yield are improved, but the device complexity increases
Solution Approach 1:
The counter current wash system introduces wash water as an intermediary medium to facilitate the removal of unfermentable solids. This intermediary fluid enables separation without requiring complex mechanical intervention, achieving high protein purity through a relatively simple wash-and-separate mechanism.
Solution Approach 2:
The system uses hydraulic principles through the counter current wash, where water flow is directed opposite to the protein stream to mechanically wash out unfermentable solids. This hydraulic approach achieves effective separation using fluid dynamics rather than complex mechanical separation devices.
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
The counter current wash system effectively reduces unfermentable solids in the protein portion, improving corn processing throughput and achieving a higher protein yield with a purer protein product, allowing for increased corn processing capacity and enhanced protein recovery.
Implementation Method 1
when the whole stillage leaves the distillation column, it is generally subjected at the back end of the process to a decanter centrifuge to separate insoluble solids or 'wet cake'
Implementation Method 2
counter current wash water that is received from a later step in the method is added to the stillage portion and the stillage portion is separated, via weights, into a water soluble solids portion and a protein portion
Data Source
AI summary
A method and system for reducing the unfermentable solids content in a protein portion, via a counter current wash, at the back end of a corn dry milling process for making alcohol is disclosed. The method can include separating the whole stillage byproduct into an insoluble solids portion and a stillage (centrate) portion, which includes protein. Thereafter, the stillage portion can be separated into a water soluble solids portion and a protein portion. The protein portion may be mixed with clean water to wash and dilute the protein portion. The diluted protein portion may be dewatered to form a dewatered protein portion and a centrate. A portion of the centrate may be used as a protein counter current wash when the protein portion is being separated from the stillage portion. The protein counter current wash reduces the amount of unfermentable solids in the protein portion and the centrate.