Anionic Flocculant for Ethanol Stillage Phase Separation
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Solution Overview
Problem
The dry milling ethanol process requires significant energy to separate and recover valuable components from stillage due to high energy inputs and mechanical separation efforts, particularly due to the presence of suspended solids which increase energy requirements in separation steps.
Innovation Solution
The method involves adding an anionic flocculant to the stillage, inducing the formation of three phases (water, particle, and oil phases), allowing for the recovery of oil and subsequent processing with reduced energy consumption, and using GRAS-certified flocculants to facilitate the separation and recycling of solids and oils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If heat and centrifuge pressures are applied to whole stillage to recover components, then separation and recovery of solids, fats, and oils is achieved, but energy consumption increases significantly
Solution Approach 1:
The flocculant is added to the stillage before centrifugation to pre-condition the suspended solids, causing them to aggregate into larger flocs that separate more easily during centrifugation. This preliminary chemical action reduces the mechanical energy needed in subsequent separation steps while improving recovery efficiency.
Solution Approach 2:
The invention changes the physical-chemical parameters of the stillage by adding flocculants that alter the surface properties and aggregation state of suspended solids. This transformation modifies the rheological properties and separation characteristics of the material, enabling more energy-efficient separation with reduced centrifuge pressures and heat requirements.
2Manufacturing precision
If centrifuging is used to separate water from whole stillage, then concentrated solids wet cake and low solids thin stillage streams are formed, but significant mechanical separation efforts and energy are utilized
Solution Approach 1:
The flocculant acts as an intermediary substance that facilitates the separation process by bridging between suspended solid particles and the liquid phase. It promotes selective aggregation of solids while leaving the liquid phase relatively unaffected, thereby simplifying the mechanical separation task and reducing the complexity of equipment requirements.
Solution Approach 2:
The invention partially replaces mechanical separation efforts with chemical flocculation. Instead of relying solely on high-energy mechanical centrifugation to separate all components, the chemical action of the flocculant performs the preliminary separation work, reducing the burden on mechanical separation devices and lowering overall system complexity.
3Quantity of substance
If thin stillage undergoes drying or evaporation to form viscous syrup, then concentrated product is obtained, but energy consumption increases
Solution Approach 1:
The flocculant is applied beforehand to remove a significant portion of suspended solids and water through enhanced settling and centrifugation. This preliminary concentration step reduces the volume and solids content that subsequently require energy-intensive drying and evaporation, thereby lowering the total energy demand while achieving the same final concentration.
Solution Approach 2:
The flocculation process extracts and removes suspended solids and associated water from the stillage stream before the evaporation stage. By taking out this material earlier in the process, the remaining liquid requires less energy for concentration, as the bulk of the separation has already been accomplished through the chemical flocculation step.
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 reduces the energy needed to process stillage, enhances oil recovery, and improves the efficiency of ethanol production by reducing shear energy requirements and improving unit operations, allowing for more efficient processing and water savings.
Implementation Method 1
adding to stillage an effective amount of at least one anionic flocculant... The flocculant induces the formation of three phases, a water phase, a particle phase, and an oil phase
Data Source
AI summary
A method of processing thin stillage in an ethanol refining operation is provided. The method comprises treating thin stillage upstream of a concentration or evaporation step with an aid comprising a sorbitan ester of a fatty acid, an ethoxylated sorbitan ester of a fatty acid, or a combination thereof, thereby forming treated thin stillage. The aid may include at least one of sorbitan monooleate, polyoxyethylene sorbitan monostearate, and polyoxyethylene sorbitan monolaurate.