Vertical Photobioreactor Counterflow Mixing for Algae Growth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing algal cultivation systems, such as open raceway ponds and enclosed photobioreactors, face inefficiencies in mixing and light distribution, leading to low productivity and high costs due to self-shading, contamination, and energy-intensive processes, making large-scale algae production economically unviable.
Innovation Solution
The implementation of vertical photobioreactors with counterflow dynamics using carbon dioxide buoyancy and spiral impressions to enhance mixing, combined with modular designs and advanced filtration systems, allows for efficient carbon dioxide utilization and algae growth, enabling scalable and cost-effective production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If open raceway ponds are used for algal cultivation, then capital costs are low, but productivity is low due to self-shading and contamination
Solution Approach 1:
The patent transitions from two-dimensional surface cultivation in open ponds to three-dimensional vertical tubular photobioreactors. This dimensional change allows light to penetrate through the transparent tubes from multiple directions, eliminating self-shading while maintaining high cell densities. The vertical configuration increases cultivation volume per unit footprint, thereby improving productivity without proportionally increasing capital costs.
Solution Approach 2:
The patent employs flexible transparent tubing as the photobioreactor medium. These thin-walled tubes allow maximum light transmission while containing the algal culture. The flexibility enables the tubes to be coiled or arranged in space-efficient configurations, and the thin walls minimize light absorption, ensuring adequate light penetration to all algal cells regardless of their position within the tube.
2Productivity
If enclosed photobioreactors are used to prevent contamination, then productivity increases, but energy consumption increases due to mixing requirements
Solution Approach 1:
The patent utilizes the algal culture's own photosynthetic activity and gas production to drive circulation. Oxygen and carbon dioxide bubbles generated during photosynthesis provide natural buoyancy forces that circulate the culture through the vertical tubes, eliminating the need for external mixing energy input. The system is self-sustaining, using its own metabolic byproducts to maintain uniform cell distribution and prevent settling.
Solution Approach 2:
The patent employs gas lift principles where carbon dioxide and oxygen gas flows injected at the bottom of vertical tubes create upward buoyancy currents. These pneumatic forces drive hydraulic circulation of the algal culture through the photobioreactor system, achieving effective mixing and distribution without mechanical agitators or energy-intensive pumping.
3Productivity
If vertical photobioreactors with counterflow dynamics are used, then carbon dioxide utilization efficiency increases, but device complexity increases
Solution Approach 1:
The patent implements dynamic counterflow circulation where algal culture flows downward through vertical tubes while carbon dioxide gas flows upward through the same tubes. This dynamic opposing flow pattern maximizes contact time and mass transfer efficiency between carbon dioxide and algae. The system adapts flow rates based on operational conditions, optimizing carbon dioxide utilization without requiring complex control mechanisms.
Solution Approach 2:
The vertical tubes serve multiple functions simultaneously: they contain the algal culture, transmit light to the algae, provide pathways for both downward liquid flow and upward gas flow, and facilitate heat exchange. This multi-functionality reduces the number of separate components needed, thereby limiting the increase in device complexity despite the advanced counterflow dynamics.
4Productivity
If large-scale algae production is implemented, then biofuel output increases, but harvesting costs increase
Solution Approach 1:
The patent's vertical tubular configuration concentrates the algal culture in a compact vertical space, making it easier to access and harvest compared to large horizontal ponds. The modular nature of the vertical tubes allows for staged harvesting where sections can be processed independently, reducing overall harvesting costs at scale.
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 approach optimizes algae growth by ensuring uniform light exposure and prolonged carbon dioxide interaction, enhancing productivity and reducing operational costs through improved mixing and harvesting efficiency.
Implementation Method 1
carbon dioxide buoyancy to drive counterflow mixing
Implementation Method 2
spiral impressions to enhance mixing
Implementation Method 3
photosynthesis is nature's way of recycling carbon that is in the biosphere. In this process, organisms performing photosynthesis, such as plants, may synthesize carbohydrates, proteins, oils, and other cellular materials using sunlight and carbon dioxide
Implementation Method 4
efficient harvesting methods, such as Coanda screens and electrostatic waves
Data Source
AI summary
Embodiments may provide photobioreactor system such as a vertical growth enhancing mixing spectrum photobioreactor (1) including but not limited to at least one downcomer tower (22) having spiral impressions (211), an upcomer tower (21), an algae-fluid input (10), an algae downward fluid flow (25) in a downcomer tower; a gas input (18) to drive a system flow (250), a gas upward flow (20) in a upcomer tower; a carbon dioxide gas input (27) having a lower mass flow of carbon dioxide than a mass flow in an upcomer tower, a carbon dioxide gas upward flow (26) in a downcomer tower; a counterflow (230) created with the algae downward fluid flow and carbon dioxide gas upward flow; and perhaps even a collection tank (64) for dewatered algae. Each photobioreactor system may be connected to provide a plurality of photobioreactor systems of which can be automatically controlled.