Microalgae Culture Control Using pH and Bicarbonate Balance
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Solution Overview
Problem
Existing culturing devices struggle to accurately control the concentration of carbon dioxide in the culturing solution using factory exhaust gas, leading to potential deficiencies or excesses that hinder satisfactory microalgae cultivation.
Innovation Solution
A culturing method and device that adjusts the temperature and pH of the culturing solution to maintain the concentration of hydrogen carbonate ions within a set range by using sensors and control units to monitor and adjust the ion concentration, temperature, and pH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If factory exhaust gas is supplied to the culturing solution to provide carbon dioxide for microalgae cultivation, then the carbon dioxide source becomes more available and cost-effective, but the concentration of carbon dioxide in the exhaust gas varies with factory operating conditions, making it difficult to accurately control the carbon dioxide concentration in the culturing solution
Solution Approach 1:
The patent introduces pH as an intermediary parameter to indirectly control carbon dioxide concentration. Instead of directly measuring and controlling CO2 concentration which is difficult with variable exhaust gas, the system measures pH (which responds to CO2 levels through carbonic acid formation) and uses pH control to achieve CO2 concentration control. The pH measurement serves as a mediator between the variable CO2 input and the desired stable CO2 concentration in the culturing solution.
2Ease of operation
If the amount of exhaust gas supplied to the culturing solution is controlled based on pH measurement values, then supply control is implemented, but it is difficult to accurately control the amount of carbon dioxide in the culturing solution due to variable CO2 concentration in exhaust gas
Solution Approach 1:
The patent implements a feedback control system where pH is continuously measured and used to adjust the exhaust gas supply rate. The pH measurement provides real-time feedback about the carbon dioxide concentration status in the culturing solution, and this feedback drives adjustments to the gas supply to maintain optimal conditions for microalgae cultivation.
3Measurement precision
If pure carbon dioxide gas is supplied to maintain hydrogen carbonate ion concentration, then carbon dioxide supply can be precisely controlled, but the system cannot utilize factory exhaust gas which contains variable concentrations of carbon dioxide
Solution Approach 1:
The patent changes the control parameter from direct CO2 concentration measurement/control to pH measurement/control. This parameter change allows the system to work with variable composition exhaust gas by controlling a different parameter (pH) that reflects the actual carbon dioxide levels in the culturing solution, thereby achieving both adaptability to exhaust gas and precise control of hydrogen carbonate ion concentration.
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 method and device ensure that the concentration of hydrogen carbonate ions remains within an appropriate range, enabling effective microalgae cultivation regardless of the amount of carbon dioxide supplied, thus promoting satisfactory growth.
Implementation Method 1
A portion of the carbon dioxide (CO2) that is dissolved in the culturing solution containing water becomes carbonic acid (H2CO3)
Implementation Method 2
Such carbonic acid is ionized in a stepwise manner into hydrogen carbonate ions (bicarbonate ions, HCO3−) and carbonic acid ions (CO32−)
Implementation Method 3
Microalgae that are cultured in a culturing solution grow and propagate due to photosynthesis using light energy, carbon dioxide, and water
Data Source
AI summary
In a culturing method, microalgae are cultured in a culturing solution while a gas containing carbon dioxide is supplied to the culturing solution. In an ion concentration acquisition step, an acquired value of a concentration of hydrogen carbonate ions in the culturing solution is obtained. In an ion concentration adjustment step, in the case that the acquired value does not reside within a set concentration range that is set beforehand, at least one of a temperature or a pH of the culturing solution is adjusted, whereby the concentration of hydrogen carbonate ions in the culturing solution is adjusted to reside within the set concentration range.