Biomass Membrane Contactor with Integrated Recirculation
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Solution Overview
Problem
Conventional membrane bioreactors face inefficiencies when handling feed streams with high concentrations of inhibitory compounds and suspended solids, as they struggle with compound exchange and separation, leading to suboptimal bioconversion efficiency.
Innovation Solution
A membrane cartridge assembly with a semi-permeable membrane and integrated recirculation and gas bubbling systems, allowing for controlled diffusion and refreshment of fluids on both sides of the membrane, enhancing compound exchange and operational control in reverse membrane bioreactors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional membrane bioreactors are used for handling feed streams with high concentrations of inhibitory compounds and suspended solids, then the system structure is simple, but the bioconversion efficiency is suboptimal due to poor compound exchange and separation
Solution Approach 1:
The system is segmented into multiple functional modules: membrane pockets for cell encapsulation, recirculation loops for fluid exchange, and gas bubbling systems for mass transfer enhancement. This modular segmentation allows each component to perform its function optimally, improving overall bioconversion efficiency while maintaining manageable system complexity through functional decomposition
Solution Approach 2:
Cells are nested within membrane pockets, which are in turn placed within the bioreactor vessel. This nested configuration allows high local cell concentration inside the membrane pockets while keeping the cells separated from the main bioreactor medium, enabling efficient compound exchange through the membrane barrier and improving bioconversion efficiency
2Reliability
If membranes are used to encapsulate cells in membrane pockets for reverse MBR applications, then compound exchange and separation improve, but the device complexity increases due to additional membrane structures and recirculation systems
Solution Approach 1:
The membrane pockets serve multiple functions simultaneously: they provide physical containment for cells, act as semi-permeable barriers for selective compound exchange, and create defined microenvironments for enhanced bioconversion. This multi-functionality reduces the need for separate components, thereby improving reliability without proportionally increasing complexity
Solution Approach 2:
The recirculation system maintains continuous fluid flow across the membrane surfaces, ensuring sustained compound exchange and preventing stagnation. This continuous action enhances mass transfer efficiency and separation performance, improving reliability through consistent operational performance rather than intermittent processing
3Productivity
If diffusion-based compound exchange through the membrane is used, then the system operation is simple, but the compound exchange efficiency is limited by passive diffusion rates
Solution Approach 1:
The system transitions from static passive diffusion to dynamic active refreshment of fluids on both sides of the membrane. The recirculation system continuously renews the feed solution contacting the membrane exterior and the internal medium contacting the membrane interior, maintaining high concentration gradients that drive faster compound exchange and improving productivity
Solution Approach 2:
Gas bubbling is introduced on the exterior side of the membrane to enhance mass transfer through hydraulic action. The rising gas bubbles create turbulence and reduce boundary layer thickness, significantly improving compound exchange efficiency beyond what passive diffusion alone can achieve, while the hydraulic recirculation system provides additional forced convection
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 configuration improves bioconversion efficiency by facilitating uniform diffusion and product harvesting, reduces bioreactor complexity, and allows independent control of operational conditions for the feed and encapsulated biomass.
Implementation Method 1
The semi-permeable membrane forms a barrier allowing for exchange of compounds across the semi-permeable membrane, such as between a fluid comprised in the interior space and a fluid at the exterior side of the membrane. Since the exchange of compounds through the membrane is principally diffusion-based
Implementation Method 2
The first means for (re)circulating a first fluid between the first outlet port and the first inlet port
Implementation Method 3
The second means for circulating a second fluid along a surface of the semi-permeable membrane opposite the interior space
Data Source
AI summary
An assembly includes a housing with opposite first and second layers. The first and second layers are spaced apart to define a confined interior space. A semi-permeable membrane is attached to the first layer, the semi-permeable membrane covering a porous area portion of the first layer. An outlet port and an inlet port are in fluid communication with the interior space. The assembly includes a first circulator for circulating a first fluid between the outlet port and the inlet port, and a second circulator for circulating a second fluid along an exterior surface of the semi-permeable membrane. The second circulator includes a fluid duct attached to or integrated within the housing. The fluid duct is isolated from the interior space and is porous to provide fluid access to an exterior surface of the semi-permeable membrane. The semi-permeable membrane forms a barrier allowing exchange of compounds across the membrane.