Sealed Vertical Photobioreactor for Microalgae Culture
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Solution Overview
Problem
Current microalgae culture methods face challenges such as high initial costs, low yields, and environmental concerns due to the use of chemical coagulants and limited productivity, especially in small-scale raceway ponds and photobioreactors, which restrict carbon dioxide introduction and oxygen release, leading to oxygen poisoning and contamination issues.
Innovation Solution
A microalgae culture system incorporating a sealed vertical photobioreactor with a micro bubble generator for sterilization, an air compression and pressure equalization device for CO2 and O2 injection, and a high-efficiency harvesting system using hollow fiber membranes, along with ozone-based sterilization to replace chlorine-based oxidizers, allowing for continuous daily harvesting and optimal growth conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional raceway pond culture system is used, then initial facility costs are low, but productivity is low due to biofilm formation and long culturing periods
Solution Approach 1:
The system divides the culture process into separate functional modules: photobioreactor for high-density culture, sterile filtration system for harvest, and biofilm reactor for wastewater treatment. This segmentation allows each component to be optimized independently, achieving high productivity without requiring expensive integrated facilities.
Solution Approach 2:
A sterile filtration system using sterile filters serves as an intermediary between the photobioreactor and the environment, enabling harvest without chemical coagulants. This intermediary component resolves the contradiction by providing a low-cost, high-efficiency harvest mechanism that maintains productivity.
2Productivity
If chemical coagulants are used for harvesting, then harvesting efficiency is improved, but secondary water pollution problems occur
Solution Approach 1:
The system replaces chemical harvesting methods with a mechanical/physical filtration system using sterile filters. This substitution eliminates chemical coagulants entirely, achieving high harvesting efficiency without generating secondary water pollution.
Solution Approach 2:
Ozone is used as a strong oxidant for sterilization and wastewater treatment instead of chlorine-based chemicals. This provides effective harvesting and treatment without the harmful byproducts associated with traditional chemical methods.
3Stability of the object's composition
If horizontal photobioreactor structure is used to prevent algae attachment, then flow is induced, but carbon dioxide introduction and oxygen release are restricted
Solution Approach 1:
The system transitions from horizontal to vertical photobioreactor configuration. This dimensional change allows gravity-assisted flow that prevents algae attachment while simultaneously enabling efficient gas exchange through the water column, resolving the contradiction between uniform distribution and productivity.
Solution Approach 2:
The system implements dynamic flow control through pumped circulation and aeration systems that adapt to cultivation needs. This dynamic approach maintains algae suspension and prevents wall attachment while optimizing carbon dioxide introduction and oxygen release throughout the culture volume.
4Ease of manufacture
If small raceway ponds are used to reduce initial costs, then facility investment is lowered, but culturing period increases due to biofilm formation
Solution Approach 1:
The system extracts and eliminates the biofilm formation problem by using sterile filtration to prevent contamination in the first place. This extraction of the contamination source allows continuous operation without the extended culturing periods required to wait for biofilm development and subsequent cleaning.
Solution Approach 2:
The system performs preliminary sterilization of the culture medium and environment before inoculation using ozone and sterile filters. This preliminary action prevents biofilm formation from the outset, enabling rapid cultivation cycles without the time losses associated with contamination and system cleaning.
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 system enables high-density, year-round microalgae production with reduced costs and environmental impact by utilizing waste CO2 and nutrients from sewage, minimizing contamination, and promoting eco-friendly growth conditions, while reusing purified water and reducing production costs.
Implementation Method 1
a device for culture broth sterilization using a micro bubble generator
Implementation Method 2
an air compression and pressure equalization device for the injection of carbon dioxide and oxygen from the atmosphere into the culture broth
Implementation Method 3
an air cooling device to cool the compressed air and condense the water contained in the compressed air
Implementation Method 4
condense the water contained in the compressed air
Implementation Method 5
a sealed vertical photobioreactor to contain a culture medium inoculated with a microalgae, the vertical photobioreactor being configured to allow light into the culture medium
Implementation Method 6
a high-efficiency harvesting device using hollow fiber membranes
Implementation Method 7
ozone-based sterilization to replace chlorine-based oxidizers
Data Source
AI summary
A microalgae culture broth producing system includes a device for culture broth sterilization using a micro bubble generator, an air compression and pressure equalization device for the injection of carbon dioxide and oxygen in the atmosphere into the culture broth. The system also includes an air chilling device to maintain suitable culture broth temperature when water temperature is too high, an automatic carbon dioxide supply device to promote photosynthesis, and a sealed vertical photobioreactor to block out pollutants and increase dissolved carbon dioxide and oxygen concentration. The system further includes a high-efficiency harvesting device using hollow fiber membranes, and a hot air drying device using the waste heat generated by air compression.