Closed Algae Photobioreactor Control for Stable CO2 Capture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for capturing carbon dioxide using algae are challenged by variable growth rates and life cycles due to factors like nutrient content, temperature, light intensity, and carbon dioxide content, which can lead to algae starvation or death.
Innovation Solution
A system and method utilizing a closed photobioreactor with a dewatering unit, cooling unit, and treatment unit, combined with a machine learning algorithm to optimize algae growth variables, including temperature and carbon dioxide levels, to produce oxygen and biomass efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high carbon dioxide content is provided to algae, then carbon capture efficiency is improved, but excess carbonic acid decreases pH and reduces enzyme activity, slowing algae growth
Solution Approach 1:
A pH control system acts as an intermediary between carbon dioxide input and algae growth. The system continuously monitors pH levels and automatically adjusts carbon dioxide flow or adds alkaline substances to maintain optimal pH range, preventing carbonic acid accumulation while preserving carbon capture efficiency.
Solution Approach 2:
The system implements feedback control by continuously measuring pH levels in the photobioreactor and using this information to adjust carbon dioxide supply rates. When pH drops below optimal levels, the system reduces carbon dioxide input or triggers alkaline addition, creating a self-regulating mechanism that maintains enzyme activity while capturing carbon.
2Productivity
If high light intensity is provided to algae, then photosynthesis efficiency is improved, but excessive light intensity induces photoinhibition and kills algae bacteria/enzymes
Solution Approach 1:
The lighting system transitions from static to dynamic control, continuously adjusting light intensity based on real-time monitoring of algae health indicators and photosynthesis rates. The system increases light intensity during optimal growth phases and reduces it when photoinhibition signs appear, maintaining high productivity while protecting enzymes.
Solution Approach 2:
The system implements periodic light cycling with varying intensities, alternating between high-intensity photosynthetic phases and lower-intensity recovery phases. This periodic action allows algae to accumulate energy during high light periods while preventing cumulative photodamage to enzymes and bacteria.
3Productivity
If high temperature is provided to algae, then metabolic rate is improved, but excessive temperature kills algae bacteria/enzymes
Solution Approach 1:
The temperature control system uses feedback from real-time temperature sensors and algae health monitoring to dynamically adjust heating and cooling rates. The system maintains temperature in the optimal range for metabolic activity while preventing thermal damage to enzymes through continuous regulation.
4Productivity
If nutrient content is increased to support algae growth, then growth rate is improved, but system complexity and cost increase
Solution Approach 1:
The system implements self-service nutrient management where algae metabolically process and recycle nutrients within the closed photobioreactor system. Nutrient solution is continuously circulated and reused, with automatic supplementation only when levels drop below thresholds, reducing the need for complex external nutrient management infrastructure.
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
The system effectively captures carbon dioxide, producing oxygen and biomass while maintaining optimal algae growth conditions, enabling the biomass to be used as biofuel, food, or fertilizer.
Implementation Method 1
algae grown from water, carbon dioxide, and light in a closed photobioreactor, producing primarily oxygen and wet biomass as products
Implementation Method 2
The hot exhaust gas stream may operate to dewater the wet biomass stream by vaporizing water in the wet biomass stream and forming steam
Implementation Method 3
introducing at least a portion of the steam to a cooling unit, thereby condensing the steam and forming the recycle water stream
Data Source
AI summary
A process for capturing greenhouse gas emissions utilizing algae may comprise feeding a carbon dioxide feed stream, a recycle water stream, and light to a closed photobioreactor, thereby forming oxygen and the algae; extracting the oxygen and at least a portion of the algae from the closed photobioreactor, the algae extracted as a wet biomass stream; introducing the wet biomass stream to a dewatering unit along with an exhaust gas stream comprising carbon dioxide, thereby forming steam, a reduced temperature exhaust gas stream, and a dehydrated biomass product; introducing at least a portion of the steam to a cooling unit, thereby condensing the steam and forming the recycle water stream; and introducing the reduced temperature exhaust gas stream to a treatment unit, thereby forming the carbon dioxide feed stream.