Continuous Fermentation Membrane Backwashing with High-Temperature Water
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Solution Overview
Problem
Conventional membrane separation techniques for microbe culture in continuous fermentation face challenges with membrane fouling, microbe proliferation control, and complex washing processes, which affect filter performance and increase costs.
Innovation Solution
A method involving continuous fermentation using a separation membrane, where high-temperature water is used for backwashing from the permeate side to control microbe concentrations and maintain filter performance, potentially containing oxidizing agents like hypochlorite or pH adjusters, and using fermentation feedstock in the washing liquid to prevent waste generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If membrane separation is used to maintain high microbe concentrations in continuous fermentation, then productivity is improved, but membrane fouling occurs quickly deteriorating permeation flux
Solution Approach 1:
The patent applies preliminary action by performing backwashing before the membrane is completely fouled. The system continuously or periodically reverses the permeate flow to prevent foulant accumulation, thereby maintaining membrane permeability and avoiding the need for frequent chemical cleanings that would interrupt production.
Solution Approach 2:
The patent implements periodic action through cyclic backwashing operations. The system alternates between normal filtration mode and backwashing mode, creating a periodic cycle that continuously cleans the membrane surface. This periodic reversal of flow prevents permanent fouling while maintaining high productivity throughout the fermentation process.
2Productivity
If fermentation time is extended to increase product yield, then productivity improves, but microbe concentration excessively increases thereby increasing transmembrane pressure
Solution Approach 1:
The patent applies feedback control by monitoring transmembrane pressure and microbe concentration continuously. When pressure exceeds a predetermined threshold or microbe concentration reaches optimal levels, the system automatically initiates backwashing or adjusts fermentation parameters, preventing excessive pressure buildup while maximizing product yield.
Solution Approach 2:
The system dynamically adjusts operating conditions based on real-time measurements. The backwashing frequency and intensity are varied according to the current state of the membrane and culture, allowing the system to maintain optimal performance throughout extended fermentation periods without excessive pressure accumulation.
3Reliability
If membrane surface is washed by chemical cleaning to remove adhered materials, then filter performance is retained, but fermentation product is adversely affected and membrane lifetime is shortened
Solution Approach 1:
The patent converts the potentially harmful chemical cleaning process into a beneficial periodic backwashing operation using the permeate itself. By reversing the flow of the fermented liquid, the system cleans the membrane of organic foulants without introducing harsh chemicals that would damage the membrane or contaminate the product, thereby extending membrane lifetime while maintaining filter performance.
Solution Approach 2:
The system performs self-service cleaning by using its own permeate flow to wash the membrane surface during backwashing. The fermented liquid, which is already part of the process, serves as the cleaning agent, eliminating the need for external chemical cleaners and reducing both membrane degradation and product contamination risks.
4Reliability
If backwashing is performed to wash membrane surface, then filter performance is maintained, but microbe concentration cannot be controlled
Solution Approach 1:
The patent applies universality by designing the backwashing system to perform multiple functions simultaneously. The same backwashing operation that cleans the membrane surface also controls microbe concentration by preventing excessive proliferation. This multi-functional approach integrates filtration maintenance with culture management into a single versatile process.
Solution Approach 2:
The system performs preliminary action by initiating backwashing before microbe concentration becomes problematic. Through continuous monitoring and proactive backwashing, the system prevents excessive microbe growth while maintaining filter performance, addressing both issues before they become critical problems.
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 washes membrane foulants, controls microbe concentrations, and improves fermentation efficiency and cost-effectiveness by reducing waste and treatment costs, enabling stable production of fermentation products.
Implementation Method 1
filtering the culture medium through a separation membrane
Implementation Method 2
washing the separation membrane with a washing liquid... which has a temperature at least 5 °C higher than the temperature of the culture medium... up to a maximum temperature of the washing water of 100 °C
Implementation Method 3
the washing liquid contains an oxidizing agent
Data Source
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AI summary
In the production and collection of a product through fermentation using a separation membrane, it becomes possible to retain filter performance for the high-concentration culturing of a microbe mixture, and at the same time control microbe concentrations, by a method for producing chemicals through continuous fermentation, including washing a membrane with a washing liquid supplied from a permeate side of a membrane unit in a continuous fermentation including: filtering a culture medium containing a fermentation feedstock, a chemical and a microbe or a cultured cell through a separation membrane; collecting the chemical from a filtrate; retaining or refluxing unfiltered remains in the culture medium; and adding a fermentation feedstock to the culture medium, in which the washing liquid is high-temperature water having a temperature higher than a temperature of the culture medium and of 150°C or less, and a concentration of the microbe in a fermenter is controlled by supplying the washing liquid.