Mid-Evaporation Insoluble Solids Removal in Corn Dry Milling
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Solution Overview
Problem
Dry milling plants face inefficiencies in evaporator operations due to viscosity issues and fouling caused by insoluble solids, limiting the concentration of dry solids that can be achieved and reducing the evaporative load, which results in a substantial portion being handled by less efficient DDGS dryers.
Innovation Solution
A method and system that involves separating whole stillage into insoluble and soluble portions, followed by multiple evaporation stages to concentrate the solubles and remove residual insoluble solids mid-evaporation, reducing the load on DDGS dryers and increasing evaporator efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If insoluble solids are removed from thin stillage prior to evaporation, then evaporator fouling is reduced, but equipment complexity and processing burden increase due to high flow rates and low solid concentrations
Solution Approach 1:
The patent applies preliminary action by performing a first evaporation step before solids removal. The thin stillage is concentrated to 15-30% total solids in evaporators before the insoluble solids are removed by a solids removal device. This preliminary concentration increases the solids content to a level where removal equipment operates more effectively, avoiding the burden of handling low-concentration solids at high flow rates.
Solution Approach 2:
The patent segments the evaporation and solids removal process into distinct stages. The first evaporation step concentrates the thin stillage, then a separate solids removal step removes insoluble solids, followed by a second evaporation step to reach final concentration. This segmentation allows each unit operation to function optimally without the compromises required by a single integrated process.
2Productivity
If insoluble solids are removed prior to evaporation, then evaporator efficiency is improved, but oil recovery is reduced due to loss of oil in the insoluble solids
Solution Approach 1:
The patent performs preliminary evaporation to concentrate the thin stillage to 15-30% total solids before removing insoluble solids. This preliminary concentration step allows oil to be recovered in the liquid phase before solids removal, preventing oil loss that would occur if solids were removed from dilute thin stillage where oil is dispersed and difficult to separate.
3Reliability
If evaporation is limited to 35% dry solids due to viscosity and fouling issues, then evaporator operation is maintained, but evaporative load on evaporators is reduced and DDGS dryer capacity becomes limiting
Solution Approach 1:
The patent extracts insoluble solids from the thin stillage stream after preliminary evaporation but before final concentration. By removing these solids at the intermediate concentration stage, the patent eliminates the source of fouling and viscosity problems that would limit final evaporation, allowing the evaporators to operate reliably at higher than 35% dry solids concentrations.
Solution Approach 2:
The patent performs preliminary evaporation to reach 15-30% total solids before solids removal, then performs a second evaporation step after solids removal to achieve final high concentration. This two-stage evaporation with intermediate solids removal allows the evaporators to handle the full evaporative load and achieve higher final concentrations than would be possible in a single continuous evaporation process.
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 allows for higher syrup solids concentrations, shifts the evaporative load from DDGS dryers to more efficient evaporators, reduces fouling, and enhances overall process efficiency by removing insoluble solids after initial evaporation, thereby improving oil recovery and energy benefits.
Implementation Method 1
the solubles portion is subjected to a first evaporation, via one or more evaporators, to remove liquid from the solubles portion
Implementation Method 2
it is generally subjected to a decanter centrifuge to separate insoluble solids or wet cake, from the liquid or thin stillage
Data Source
AI summary
The present invention relates generally to corn dry-milling, and more specifically, to a method and system for removing insoluble solids mid-evaporation in a corn (or similar carbohydrate-containing grain) dry milling process for making alcohol, such as ethanol, and/or other biofuels/biochemicals. In one example, the method for removing residual insoluble solids in a grain dry milling process includes separating a whole stillage byproduct into an insoluble solids portion and a solubles portion, which includes residual insoluble solids. Then, the solubles portion is subjected to a first evaporation, via one or more evaporators, to remove liquid from the solubles portion to define a concentrated solubles portion. After the first evaporation, the residual insoluble solids are separated from the concentrated solubles portion. And thereafter, the concentrated solubles portion is subjected to a second evaporation, via one or more evaporators, to remove additional liquid from the concentrated solubles portion.