Membrane Washing for Sugar Purification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nanofiltration and reverse osmosis membranes used in producing sugar liquids from cellulose-containing biomass suffer from fouling due to organic substances and inorganic ions, leading to decreased washing effectiveness and membrane degradation, especially when attempting to remove fermentation-inhibiting substances, which hampers repeated use and efficiency.
Innovation Solution
A two-step washing method involving acid washing followed by alkali washing, with specific pH ranges for the washing solutions, is employed to remove fouling from nanofiltration and reverse osmosis membranes, utilizing acids like nitric acid and alkalis like sodium hydroxide, and including a preliminary water washing step to prevent further fouling and enhance membrane recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If nanofiltration and reverse osmosis membranes are used to remove fermentation-inhibiting substances from saccharified liquid, then the purity of sugar liquid is improved, but fouling of membranes occurs due to organic substances and inorganic ions
Solution Approach 1:
The patent applies preliminary action by performing water washing before the main filtration process. This preliminary step removes part of the organic substances and inorganic ions from the saccharified liquid, reducing the fouling load on the nanofiltration and reverse osmosis membranes during the subsequent purification process.
Solution Approach 2:
The patent uses an intermediary approach by introducing a water washing step as a mediator between the saccharified liquid and the membrane filtration process. This intermediary step prepares the feed liquid by removing excess fouling substances, allowing the main filtration process to focus on removing fermentation-inhibiting substances while minimizing membrane fouling.
2Reliability
If membranes are washed repeatedly to remove fouling, then membrane performance is restored, but washing effectiveness decreases over time
Solution Approach 1:
The patent applies preliminary action in the washing process by performing water washing before chemical washing. This preliminary water washing step removes loose fouling substances and inorganic ions, preparing the membrane surface for more effective chemical washing and reducing the time needed for subsequent chemical treatment steps.
Solution Approach 2:
The patent segments the washing process into distinct stages: water washing followed by chemical washing with specific pH solutions. This segmentation allows each step to target different types of fouling substances efficiently, restoring membrane performance more effectively than a single-step washing approach.
3Manufacturing precision
If acid washing is performed to remove inorganic ion fouling, then membrane permeability is improved, but organic substance fouling remains
Solution Approach 1:
The patent segments the fouling removal process by separating acid washing and alkali washing into distinct sequential steps. Acid washing targets inorganic ion fouling and restores membrane permeability, while the subsequent alkali washing step addresses organic substance fouling, ensuring comprehensive fouling removal.
Solution Approach 2:
The patent maintains continuity of useful action by immediately following acid washing with alkali washing without significant interruption. This continuous multi-step washing approach ensures that as one type of fouling is removed, the next washing step addresses the remaining fouling substances, maintaining overall washing effectiveness.
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 method effectively removes fouling from membranes, allowing for repeated use and maintaining high washing effectiveness, as evidenced by pure water flux ratios exceeding 80%, thereby ensuring efficient production of purified sugar liquids.
Implementation Method 1
a method in which a nanofiltration membrane and/or reverse osmosis membrane is/are used
Implementation Method 2
a method in which a nanofiltration membrane and/or reverse osmosis membrane is/are used
Implementation Method 3
fouling of the membrane(s) caused by the influence of organic substances and inorganic ions is removed by washing
Implementation Method 4
a two-step washing step, wherein in a first washing step an organic acid, e.g. citric acid is used and in a second washing step, an alkaline washing liquid is used
Data Source
Figure 1~2
Figure 3~4
AI summary
A method for producing a sugar liquid, the method comprising: a step of filtering a saccharified liquid derived from cellulose-containing biomass, through a nanofiltration membrane and/or reverse osmosis membrane; and a two-step washing step of washing the nanofiltration membrane and/or reverse osmosis membrane after the filtration, with an acid washing liquid and then with an alkali washing liquid; is provided. A method for producing a sugar liquid in which a cellulose-derived sugar liquid is processed through a nanofiltration membrane and/or reverse osmosis membrane, wherein a contaminated separation membrane(s) is/are effectively washed, is provided.