CO₂ can be captured using algae which then off-sets the capital investment and on-going expenses of the CO₂ capture technology by creating high value products from algae (i.e. bio-diesel, livestock feed and purified water). This process aims to be independently profitable regardless of future carbon taxes or carbon trading systems.
As part of the project aim to develop process engineering strategies for the capture of CO₂ using algae with the subsequent creation of high value products, a wide ranging research study has been instigated and the initial results include:
- Energy balance study for the removal of water from the algae cell culture. The algae culture is extremely dilute (< 0.2 % w/v), hence a great deal of energy is required to purify the algae. Tangential flow filtration, centrifugation, and evaporation are compared with other available methods.
- The lipids need to be extracted from the algae for the creation of the bio-diesel. A range of extraction methods are considered and compared including novel extraction solvents and processes.
- Selection of the most suitable algae species in terms of robustness, lipid production, CO₂ sequestration, growth rates and growth requirements (medium, macro and micro nutrient requirements).
- Bioreactors harnessing green algae can absorb huge amounts of CO₂ and NO₂ emissions however high CO₂ may not result in a feedstock suited to diesel production. The effect that the algae feedstock has on further downstream unit operations is considered in order to create a cohesive, integrated process.