CO₂ capture
Australia currently generates 75 per cent of its electricity from coal, resulting in high levels of CO2 emissions and increasing concerns about climate change. Our multi-disciplinary team have developed cost-effective methods for capturing and storing CO2 by building and operating capture pilot plants. This illustrates that coal-fired power plants, smelters, kilns and steel works can be retrofitted using our technology.
By reducing the cost of the capture process, our technology can be widely adopted, not just in Australia, but in developing countries which depend on coal for their energy supply. This will help meet the world’s energy needs while reducing CO2 emissions.
Absorbent development
The development of aqueous amine based absorbent technology has progressed from early-stage bench research to large scale and long-term pilot testing and commercial viability. Its lineage can be traced back to the work started in 2004 and is tightly entwined with numerous pilot plant campaigns that have both validated the research and presented new unexpected challenges.
CSIRO Energy has narrowed its research focus from an initial broad research program to the areas shown.
The rationale was to develop absorbents of improved performance that could be used in existing carbon capture processes. Initially, our research strategy involved developing and using a differential scanning calorimetry to rapidly determine the absorption capacity and rate of CO2 absorption from a large range of amines, using very small samples at fixed conditions. After evaluating over 100 commercially available amines, our data analysis indicated heterocyclic amines as a class with appealing performance. As a result, we identified heterocyclic amines as the focus for further research both for commercially available amines and as the structural blueprint for synthesising novel amines.
Cyclic capacity as the difference in equilibrium liquid CO2 loading (mol CO2 / mol amine) between rich conditions (40°C, 15 kPa CO2 partial pressure) and lean conditions (120°C, 15 kPa CO2 partial pressure) for MEA and aromatic amines BZA and CAL007 all at 5 mol/L total amine concentration.
Heavy industry and other hard-to-abate emissions
The main component of CSIRO’s CAL absorbent technology has been demonstrated at scale for 5000 hours and is now included as a proprietary component in the ProTreat® processing modelling package from Optimized Gas Treating, Inc. This provides a platform for absorbent formulation, process design, simulation and optimisation that the team is undertaking for emissions from industrial gas streams such as those from cement manufacturing, aluminium smelting and biogas upgrading.
Looking into the future
Closing the carbon cycle with direct air capture (DAC) and utilisation
Using the successful development of amine-based post-combustion capture technologies as a template, the team is now addressing the challenging field of direct air capture (DAC). The low concentrations of CO2 in the air require much larger gas-liquid contactors and more energy-intensive regeneration processes compared to more concentrated point sources. Our initial techno-economic analysis revealed the potential to reduce direct air capture costs to levels below $100 per tonne of CO2. This can be achieved through the use of cheaper equipment materials, process and equipment innovation and modular scale-up. Cost-effective direct air capture processes have considerable potential to contribute to negative emission and net zero emission fuels and can be readily added to existing CCUS hubs. In combination with utilisation, DAC closes the carbon cycle.
