Why is this research needed?

Effective CO2 capture and storage (CCS) techniques are urgently needed to limit global warming to 1.5°C and mitigate the adverse effects of climate change. The UK aims to capture over 50 million tonnes of CO2 per year by 2035 to meet its 2050 net-zero goal. Among the various methods, direct air capture (DAC) is particularly promising because it removes CO2 directly from the atmosphere, offering a highly flexible solution.

According to the IEA DAC (2022) report, 18 DAC plants worldwide capture almost 0.01 million tonnes of CO2 annually. To reach gigatonne levels by 2050, DAC deployment needs to grow rapidly, by about 50% annually. However, current DAC technology is expensive due to the low concentration of CO2 (0.04%) in the atmosphere and the limited development of efficient adsorbents. Therefore, maximizing DAC’s viability relies on overcoming the critical challenge of developing the most cost-effective adsorption materials. Our research aims to advance the development of the cost-effective solid adsorbent, silica-alkoxylated polyethyleneimine (APEI), specifically for DAC, tailored for efficient fixed-bed operation.

This involves two key novel steps: 1) optimizing APEIs for specific DAC conditions using a new mathematical model, to balance CO2 adsorption efficiency at ambient temperatures and long-term stability; and 2) developing silicas with optimized pore structures for APEI loading and suitable particle sizes for fixed-bed operation. Inspired by our successful ACT3 project (ABSALT – Accelerating Basic Solid Adsorbent Looping Technology, http://www.act-ccs.eu/act3), this research builds upon an advanced method we developed for producing silica-APEI for industrial CO2 capture. This innovation resulted in reduced costs and superior performance. Notably, the patented production method from ABSALT can also be applied to silica-APEI for DAC applications, promising cost savings in overall material production. This collaborative multidisciplinary project, led by the University of Nottingham (UoN), will be working closely with industry and international partners: PQ Corporation and BASF (Germany) – global manufacturers of silicas and PEI. Additionally, the project includes the Woodside Monash Energy Partnership between Monash University and Woodside in Australia, a university-industry research initiative focused on decarbonization and developing fixed-bed DAC technology. We will test the optimized APEI loaded on larger particle-sized silicas on a 2 kg scale at Monash in this project. This will pave the way for further scale-up to facilitate testing in their demonstration plants, each requiring 100 kg of absorbent. Our work not only delivers affordable, optimized adsorbents but also promises scalability, revolutionizing DAC technology and contributing to global net-zero efforts.

What is this research investigating?

O1) To unravel the impact of alkoxylation degree on alkoxylated polyethyleneimine (APEI) on CO2 adsorption efficiency (CO2 adsorption capacity and kinetics) and thermal stability under air conditions (based on existing ABSALT results); Then building a mathematical model for APEI optimization for different direct air capture (DAC) application conditions (temperature and moisture).

O2) To select the suitable silica with sufficient porosity (pore volumes around 1.6 ml/g) to maintain PEI loadings and adsorption capacity for DAC, with larger particle sizes (ca. 0. 5 mm) for fixed bed operation.

O3) To compare the CO2 adsorption efficiency and thermal stability of optimized silica-APEI to Lewatit ion-exchange resin, which is commercially available and has been widely trialled for DAC.

O4) To further develop the optimized silica-APEI for scaling up to 2 kg testing at the Woodside Monash Energy Partnership at Monash University.

What does the research hope to achieve?

This project will act as a catalyst for encouraging allied research and scale-up of adsorbents not only for DAC but also to accelerate other CCS technologies. The successful outcome will directly contribute to the UK’s net zero targets and achieve broader impacts on the environment, society and economy by being:

• Cost-effective: The silica-APEI developed in this research will have low production costs through an organic-free production procedure while maintaining high CO2 adsorption efficiency and stability, leading to lower CO2 capture costs compared to other DAC materials.
• Environmentally beneficial: High CO2 capture rates under ambient conditions make it an excellent material to meet the urgent need for annual growth rates of nearly 50%, rapidly scaling DAC deployment to gigatonne levels by 2050 to achieve net-zero targets.
• Accelerating demonstration-level DAC: The proposed project will implement a high-level design and demonstrate the silica-APEI concepts at a 2kg scale initially, with plans for the 100 kg scale for future testing at Monash.
• The multidisciplinary and international value of this project comes from solid collaboration among partners from three countries, combining expertise in materials and adsorbent preparation (PQ Corporation, BASF, and the University of Nottingham) and laboratory and pilot-scale testing (Woodside Monash Energy Partnership). Additionally, the Korea Institute of Energy Research (KIER)’s interest in the DAC material, and experience in testing silica-APEI on a large scale, positions us well to advance further to full-scale demonstrations in the future.

After the successful completion of the proposed project, we will be in a position to make the unique, cost-effective adsorbents available for DAC to maximize the impact. Therefore, it can significantly benefit for a wide range of stakeholders, including:

• The researchers trained through the project will provide high-quality expertise for the UK CCS research community and energy industry, and contribute to the further development of CCS technologies in the UK.
• Environmental and Climate Organizations: Developing cost-effective DAC technologies will accelerate carbon capture and storage (CCS) initiatives, directly contributing to the UK’s net zero target. By lowering CO2 capture costs and improving efficiency, this research supports global efforts to combat climate change.
• Industry and Businesses: Companies (including but not limited to PQ Corporation and BASF) involved in carbon-intensive industries will benefit from more affordable and efficient DAC technologies, helping them meet regulatory requirements and reduce their carbon footprints.
• Government and Policymakers: Governments and policymakers aiming to achieve national and international climate goals will find this research invaluable. The ability to scale DAC deployment rapidly to gigatonne levels by 2050 will be crucial for meeting net-zero targets.
• Academic and Research Institutions: The multidisciplinary collaboration between PQ Corporation, BASF, the University of Nottingham, Monash University and Woodside, fosters knowledge exchange and innovation. Researchers and students will gain access to cutting-edge technologies and methodologies, enhancing their educational and professional development. This will also inspire researchers to devote themselves to CCS research.
• Global Communities: Society at large will benefit from the environmental improvements brought about by reduced CO2 levels. A more stable climate will contribute to public health and overall well-being.
• Economic Stakeholders: The research promises broader economic impacts by lowering the costs of DAC technologies, which can lead to new business opportunities, job creation, and sustainable economic growth.