Fermentation Process Yield Enhancement via Stillage Recycling
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Solution Overview
Problem
Existing processes for producing ethanol and biogas from starch-containing materials are energy and water intensive, and they often result in low ethanol yields and inefficient biogas production.
Innovation Solution
A process that involves forming a slurry with milled starch-containing material, water, whole stillage, and outflow from a biogas unit, followed by liquefaction, saccharification, and fermentation to produce ethanol, with a yield enhancing composition of enzymes and microorganisms added at various stages to enhance ethanol and biogas yields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional ethanol production processes are used, then ethanol can be produced from starch-containing materials, but energy and water consumption are high
Solution Approach 1:
The patent recovers and recycles stillage and biogas unit outflow back to the slurrying step, transforming waste streams into valuable process liquids that provide water, nutrients, and residual starch for further ethanol production. This closed-loop approach reduces fresh water consumption and energy input while enhancing ethanol yield through multiple fermentations.
Solution Approach 2:
The patent implements continuous recycling of process liquids and materials through the biogas unit and back to the slurrying step, maintaining continuous useful action rather than discrete batch operations. This ensures sustained ethanol production while minimizing energy and water waste through repeated utilization of process streams.
2Productivity
If conventional biogas production is used, then biogas can be produced from stillage, but ammonium concentration exceeds acceptable levels
Solution Approach 1:
The patent employs feedback control by monitoring ammonium concentration in the biogas unit and adjusting process parameters accordingly. The outflow from the biogas unit is recycled back to the slurrying step where ammonium can be assimilated by microorganisms, preventing harmful accumulation while maintaining biogas production efficiency.
Solution Approach 2:
The patent changes operational parameters of the biogas unit, specifically controlling ammonium concentration to remain below 6000 ppm NH4-N through optimized digestion conditions and recycling rates. This parameter control enables simultaneous achievement of high biogas yield and prevention of ammonium-related harmful effects.
3Productivity
If yield enhancing composition is added to enhance ethanol yield, then ethanol production increases, but process complexity increases
Solution Approach 1:
The patent uses self-service by employing native microorganisms present in the stillage and biogas unit outflow to perform saccharification and fermentation. This eliminates the need for adding external enzymes or microbial cultures, thereby enhancing ethanol yield through efficient biological conversion while avoiding the complexity associated with enzyme addition, sterilization, and process control.
Solution Approach 2:
The patent implements multi-functionality by using the same biogas unit and recycling system to simultaneously produce biogas, treat stillage, and provide nutrient-rich process liquids that enhance subsequent ethanol fermentation. This universal approach achieves multiple objectives including waste reduction, energy production, and ethanol yield enhancement without requiring separate dedicated systems for each function.
Data Source
AI summary
The present invention concerns a process for producing fermentation products, such as ethanol, and a biogas unit, wherein a yield enhancing composition comprising at least one, at least two, at least three, at least four, or at least five different types of enzymes and/or at least one, at least two, at least three, at least four, or at least five different microorganisms is added to the whole stillage that is fed to the slurrying step and/or the biogas unit, outflow of the biogas unit before being mashed in the slurrying step; thin stillage that is fed to the slurrying step, residual materials resulting from purification of the oil and/or of the protein product that are fed to the biogas unit, wet cake that is fed to the slurrying step and/or fed to the biogas unit, added to the biogas unit, and/or biomass added to any one of the preceding steps.