Lignocellulosic Ethanol Membrane Separation With Controlled Suspended Solids
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Solution Overview
Problem
The production of ethanol from lignocellulosic raw materials is hindered by high costs, primarily due to the inefficiency of enzyme utilization and membrane clogging during solid-liquid separation, which reduces the flow rate of permeation and enzyme recovery.
Innovation Solution
A method involving saccharification and fermentation in a reaction system with controlled suspended solids concentration (4 to 9.5% by mass) followed by membrane separation using organic membranes, particularly ultrafiltration, to enhance permeation flow rates and enzyme recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If membrane separation is performed to recover enzyme from fermentation mixture, then enzyme recovery is improved, but membrane pore blockage and surface deposition occur due to suspended solids, reducing permeation flow rate
Solution Approach 1:
The patent applies preliminary action by performing solid-liquid separation before membrane separation to remove suspended solids that would cause pore blockage. This pre-treatment step prepares the fermentation mixture by removing problematic solids before the mixture contacts the membrane, preventing the worsening of membrane performance while still enabling effective enzyme recovery through the subsequent membrane separation step.
Solution Approach 2:
The patent uses an intermediary approach by introducing a solid-liquid separation step as a mediator between the fermentation process and membrane separation. This intermediary step handles the suspended solids problem, allowing the membrane separation to proceed efficiently without direct exposure to solids that would cause blockage, thus maintaining both high enzyme recovery and membrane reliability.
2Productivity
If suspended solids concentration is increased to maintain enzyme activity, then enzyme performance is improved, but membrane pore blockage increases, reducing permeation flow rate
Solution Approach 1:
The patent applies segmentation by dividing the processing sequence into distinct stages: first maintaining high suspended solids concentration during fermentation to preserve enzyme activity, then separating solids from liquid before membrane filtration. This segmentation allows the system to benefit from high enzyme activity during the fermentation phase while avoiding membrane blockage during the separation phase, as the solids are removed before contacting the membrane.
Solution Approach 2:
The patent uses preliminary action by performing solid-liquid separation before membrane filtration to remove suspended solids that would block membrane pores. This pre-treatment allows the system to maintain high suspended solids concentration during fermentation for optimal enzyme activity, while preventing permeation flow rate reduction during the subsequent membrane separation step.
3Reliability
If multiple solid-liquid separation steps are performed to remove suspended solids, then membrane performance is maintained, but process complexity and production cost increase
Solution Approach 1:
The patent applies the taking out principle by extracting and removing suspended solids from the fermentation mixture through solid-liquid separation before membrane filtration. This extraction of problematic solids in a single dedicated step protects the membrane from blockage while avoiding the need for multiple separation steps, thus maintaining membrane performance without excessive process complexity.
Solution Approach 2:
The patent uses parameter changes by optimizing the suspended solids concentration to be within a specific range (1-10% by mass, preferably 3-8%) during fermentation. This parameter optimization allows sufficient enzyme activity while limiting the amount of solids that would cause membrane blockage, reducing the need for multiple separation steps and simplifying the overall process while maintaining membrane performance.
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
Improves the permeation flow rate through separation membranes, increasing enzyme recovery and reducing production costs by maintaining a specified range of suspended solids concentration.
Implementation Method 1
membrane separation using organic membranes, particularly ultrafiltration
Implementation Method 2
an ethanol-fermenting microorganism is added into the same reaction tank, and the enzymatic saccharification reaction and ethanol fermentation are performed therein
Implementation Method 3
an enzymatic saccharification methods using saccharification enzymes such as cellulolytic enzymes
Data Source
Figure 1
AI summary
The present invention provides a method for producing ethanol with an improved flow rate of permeation in membrane separation. More specifically, the present invention provides a method for producing ethanol from a lignocellulosic raw material, comprising a first step of performing saccharification and fermentation in a reaction system containing a lignocellulosic raw material, a saccharification enzyme, a yeast, and water, thereby producing ethanol; and a second step of treating, with a separation membrane, a first mixture containing the ethanol, water, the yeast, the saccharification enzyme, and a reaction residue of the lignocellulosic raw material, obtained in the first step, thereby obtaining a mixture containing the ethanol and water, and a second mixture containing the yeast, the saccharification enzyme, water, and the reaction residue of the lignocellulosic raw material; wherein the concentration of suspended solids in the first mixture is from 4 to 9.5% by mass.