Algae Raceway Cultivation Using Bore Waves for Direct Air Capture
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Solution Overview
Problem
Existing algae cultivation systems face high operational costs and location limitations due to the need for concentrated CO2 and N2 supplementation, with spontaneous diffusion of atmospheric gases being insufficient for large-scale biomass productivity.
Innovation Solution
The system employs sloped channels with bore waves and air-liquid mixing devices to disrupt the air-liquid interface, directly capturing atmospheric CO2 and N2 into the algae cultivation fluid, maintaining sufficient nutrient concentrations for high biomass productivity without external supplementation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pure CO2 is bubbled into the raceways to support high rates of photosynthesis, then biomass productivity is improved, but operational cost increases significantly
Solution Approach 1:
The patent changes the concentration parameter of CO2 from pure (100%) to atmospheric levels (~0.04%), and adjusts the pH parameter to alkaline conditions (pH 9-11) to enhance the driving force for CO2 absorption from air, thereby reducing operational costs while maintaining productivity
Solution Approach 2:
The system uses atmospheric air as a free source of CO2, eliminating the need to purchase expensive pure CO2. The alkaline pH conditions create a self-driven absorption mechanism where CO2 naturally dissolves into the cultivation fluid without requiring external pressurization or concentrated sources
2Quantity of substance
If flue gas is used as a CO2 source to reduce cost, then operational cost is reduced, but location flexibility is lost
Solution Approach 1:
The system uses atmospheric air, which is universally available everywhere, as the CO2 source. This eliminates the dependency on specific industrial facilities like flue gas sources, making the algae farm universally locatable anywhere with sufficient land area
3Quantity of substance
If N2 absorption from atmosphere is used in raceway cultivation, then operational cost is reduced, but productivity is insufficient due to lack of intense air mixing
Solution Approach 1:
The patent applies periodic wave action (bore waves) to the cultivation fluid surface, creating intermittent intense mixing events that periodically replenish dissolved N2 and CO2 throughout the water column, maintaining high productivity without continuous energy input for aeration
4Quantity of substance
If atmospheric CO2 absorption is used without wave action, then operational cost is reduced, but biomass productivity is insufficient
Solution Approach 1:
Periodic bore waves are applied to create intermittent intense mixing that periodically replenishes atmospheric CO2 throughout the cultivation fluid, achieving high productivity with minimal operational cost by using natural atmospheric CO2 rather than purchased pure CO2
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 enhances biomass productivity to at least 8 g/m2d, reduces energy consumption, and allows for flexible farm location by utilizing atmospheric nutrients, improving resilience to process perturbations.
Implementation Method 1
Algae utilize photosynthesis to fix CO2 for growth
Implementation Method 2
applying bore waves through the algae cultivation fluid at a bore wave frequency sufficient to disrupt an air-liquid interface of the algae cultivation fluid to induce direct absorption of atmospheric carbon dioxide or atmospheric nitrogen from air into the algae cultivation fluid
Implementation Method 3
Some blue-green algae or cyanobacteria can fix N2 directly from the atmosphere
Data Source
AI summary
Embodiments of the disclosure provide systems and methods for supplying an algae cultivation fluid with nutrients (e.g., carbon dioxide and nitrogen) directly from the atmosphere. Supplying nutrients directly from the atmosphere reduces operational costs and environmental impacts, as well as provides greater flexibility in locating algae farms.