1. Present yourself and your organization.
My name is Muhammad Nauman Saeed. I completed my bachelor’s in mechanical engineering from NUST, Islamabad, and later pursued a Master’s in Sustainable Energy Systems at Chalmers University of Technology. I did my master's thesis at the Energy Technology Division, where I now work as a doctoral student in the Passive DAC project. The research group I’m part of was previously called the Chemical Looping Group, with a strong focus on chemical looping technologies such as chemical looping combustion (CLC) and chemical looping gasification (CLG). However, following the approval of the Passive DAC project and my induction into the group, the focus expanded, and we are now known as the Carbon Capture Group to reflect our broader scope in negative emissions research.
2. Describe your role in the project and the expertise you contribute.
In the Passive DAC project, I currently focus on the carbonation of slaked lime (Ca(OH)₂). My role involves designing and conducting lab-scale experiments to study how environmental parameters such as temperature, relative humidity, CO₂ concentration, and airflow affect the carbonation rate. I also work with CFD modelling to simulate airflow over the slaked lime plates and predict carbonation rates. These simulations will later be validated against the experimental results. My background in process modeling and sustainability provides the basis for understanding and optimizing the system.
3. What are you currently working on within the project?
I am currently focused on conducting a series of lab-scale experiments to investigate the carbonation behavior of slaked lime under controlled conditions. The custom-built experimental setup allows me to vary parameters such as temperature, CO₂ concentration, relative humidity, and airflow to observe their impact on carbonation rates. I am also preparing and testing different types of slaked lime plates, exploring how factors like material composition and plate thickness influence performance. Alongside the experiments, I am working with CFD modelling to simulate airflow over the plates and predict carbonation behavior, which will later be validated using the experimental results.
Additionally, I am supervising a master’s thesis on the life cycle assessment of slaked lime production from calcium-rich industrial byproducts. The process involves acid leaching, impurity removal, and Ca(OH)₂ precipitation using the pH swing method.
4. Project progress/milestones. What would you consider your biggest achievement or success in the project so far? What aspects do you find most exciting or valuable?
The biggest milestone so far has been the successful design and commissioning of a lab-scale experimental setup capable of varying key environmental parameters such as temperature, CO₂ concentration, relative humidity, and airflow to study their impact on slaked lime carbonation.
Unlike most previous studies, which focus on high-temperature conditions and limited parameter ranges, this setup allows us to explore carbonation at ambient conditions with a wide combination of variables. This opens the door to building an extensive experimental matrix and gaining deeper insight into the carbonation mechanisms.
What I find most exciting is the iterative nature of the work. While running experiments, I’m constantly identifying ways to refine and improve the setup. It’s both challenging and rewarding to face unexpected problems and find creative, hands-on solutions.
5. What are the next steps for you or your wp/team in the project?
The next step is to conduct a full series of experiments using the setup to evaluate how different parameters affect the carbonation of Ca(OH)₂. These experiments will be followed by sample analysis and characterization to improve our understanding of the carbonation process. Alongside the experimental work, I will continue refining the CFD modelling to improve the accuracy of air flow simulations and better predict carbonation rates under varying conditions. Once we have enough experimental data, the CFD results will be validated and fine-tuned.
Additionally, I will continue working with the team on the LCA of slaked lime production, specifically focusing on the environmental impacts of producing slaked lime from industrial byproducts using the pH swing method, and how these can be minimized in the broader context of carbon capture.
6. Looking ahead, what role do you think Passive DAC systems could play in the future of carbon management? Why is this project important?
Passive DAC systems offer a promising, low-cost, and low-energy approach to carbon removal especially when combined with materials like slaked lime that can be produced from industrial waste. This project is important because it connects negative emissions with resource circularity, helping to address both climate and waste challenges in a sustainable way.
7. Recent activities
Last summer, I presented a poster at the 3rd International Conference on Negative CO₂ Emissions in Oxford. The work focused on extracting calcium from industrial byproducts and producing Ca(OH)₂ via the pH swing method. The concept was well received and generated interest for its innovative approach to negative emissions and circular material use.