Carbon capture, utilization, and storage has emerged as a critical pathway in nearly every credible scenario for achieving net-zero emissions. The challenge is immense. Global emissions remain in the tens of gigatonnes each year, and future projections suggest that several gigatonnes of carbon dioxide will need to be captured annually by mid-century. This is not simply a scientific challenge. It is an engineering challenge of scale, reliability, and speed.

Within this broader effort, one part of the system stands out as both a bottleneck and an opportunity. That part is the absorber, where carbon dioxide is physically or chemically removed from industrial gas streams. The effectiveness of this step determines not only how much carbon can be captured, but also how much energy is required and how large and complex the equipment must be. Improving this stage could unlock faster and more cost-effective deployment across industries.

This is where the work of Dr. Ali Najarnezhadmashhadi and his colleagues at Grimaldi Development, in collaboration with KTH Royal Institute of Technology, becomes especially significant. Through a combination of experimental studies and advanced modeling, his research traces a path from laboratory exploration to real-world industrial application, offering insight into how carbon capture technologies can evolve from promising concepts into scalable solutions.

At its core, carbon capture often relies on a deceptively simple principle. A gas containing carbon dioxide is brought into contact with a liquid solvent that absorbs the gas. This interaction occurs inside a device known as a gas–liquid contactor, often referred to as an absorber. The efficiency of this interaction depends on how effectively the gas and liquid phases mix, how large the contact surface is, and how long they remain in contact.

Traditional systems, such as packed columns, have been widely used for decades. These often rely on structured materials that increase the surface area between gas and liquid. While effective, they come with drawbacks. They can be large, complex, and sensitive to fouling, pressure drop, and changes in operational conditions. In industrial environments where space is limited and conditions vary, these drawbacks can become serious barriers to deployment.

Spray towers offer an alternative approach. Instead of relying on internal structures, they disperse the liquid into fine droplets that interact directly with the gas. This simplicity gives them advantages in terms of lower pressure drop and a larger surface for gas–liquid interaction. However, their performance depends heavily on factors such as droplet size, flow configuration, and mixing dynamics.

Early research into spray towers has shown that smaller droplets can significantly improve carbon capture efficiency by increasing the surface area available for absorption. In laboratory experiments, systems using potassium carbonate as a solvent demonstrated how variations in flow configuration can dramatically influence performance. For example, configurations that enhance turbulence and mixing can lead to higher capture efficiency by improving contact between phases.

These findings highlight an important shift in thinking. Instead of focusing solely on the chemistry of the solvent, researchers are increasingly examining the physical dynamics of the system. How fluids move, mix, and interact within the reactor becomes just as important as the chemical reactions themselves.

This perspective is central to the work carried out by Dr. Ali Najarnezhadmashhadi and his colleagues, including Professors Lars Pettersson, Christophe Duwig, and Henrik Kusar. Their research at KTH and in partnership with industrial stakeholders explores how spray-based systems can be optimized through both experimentation and computational modeling. In one study, a lab-scale spray tower was used to investigate how different flow configurations affect carbon dioxide absorption. The results revealed that design choices at even a small scale can have a significant impact on efficiency.

Building on this foundation, the research progressed to pilot-scale experiments under industrial conditions in collaboration with the Swedish company Grimaldi Development. A modular spray tower system was deployed at a waste-to-energy facility in Sweden, allowing researchers to observe how the technology performs in a realistic setting. This step is crucial, as many technologies that perform well in the laboratory struggle when exposed to the complexities of real-world operations.

The pilot-scale study combined experimental data with computational fluid dynamics modeling to provide a detailed picture of how gas and liquid interact within the tower. The results showed that factors such as droplet size, liquid-to-gas ratio, and gas inlet configuration all play critical roles in determining performance. Smaller droplets were found to enhance dispersion and increase residence time, both of which improve carbon dioxide absorption.

One particularly important insight was the identification of distinct flow regions within the tower. These regions, characterized by varying levels of turbulence and mixing, influence how effectively the gas and liquid interact. By understanding these dynamics, engineers can design systems that maximize beneficial interactions while minimizing inefficiencies.

This integration of experimental observation and numerical modeling represents a powerful approach to technology development. It allows researchers to move beyond trial and error, using detailed simulations to predict how changes in design will affect performance. In doing so, it accelerates the process of optimization and reduces the risks associated with scaling up new technologies.

Scaling up is, in many ways, the defining challenge of carbon capture. It is not enough to demonstrate that a system works in a controlled environment. It must also be shown that it can be manufactured, installed, and operated reliably across a wide range of industrial settings. This requires a focus not only on efficiency, but also on simplicity, robustness, and adaptability.

A white technical paper written by Najarnezhadmashhadi and colleagues at Grimaldi Development emphasizes this point clearly. Industrial environments are highly variable, with differences in gas composition, temperature, and operational constraints. A solution that works well in one context may not perform as effectively in another. As a result, flexibility and modularity become key design criteria.

Spray-based systems, particularly those that incorporate process intensification strategies, offer a promising pathway forward. By increasing the effectiveness of gas–liquid interaction without introducing complex internal structures, these systems aim to combine high performance with mechanical simplicity, with the potential to reduce both capital and operating costs. This balance is essential for achieving widespread adoption.

Another important consideration is energy consumption. Carbon capture processes can be energy-intensive, particularly during solvent regeneration. Improving the efficiency of the absorption step can reduce solvent consumption and, as a result, the overall energy demand of the system, making it more economically viable. This, in turn, can accelerate deployment by lowering the cost barrier for industrial operators.

The broader implications of this research extend beyond any single technology. They reflect a shift in how we approach the challenge of decarbonization. Rather than seeking a one-size-fits-all solution, there is a growing recognition that different industries and applications will require tailored approaches. Technologies must be designed with real-world constraints in mind, balancing performance with practicality.

This shift also underscores the importance of collaboration between academia and industry. The journey from laboratory experiments to pilot-scale testing and eventual deployment requires expertise from multiple disciplines. It involves not only scientific discovery, but also engineering design, manufacturing, and operational experience.

The work of KTH and Grimaldi Development exemplifies this collaborative approach. By connecting fundamental research with industrial application, it provides a roadmap for how innovative ideas can be translated into practical solutions. It also highlights the value of iterative development, where insights gained at each stage inform the next.

Looking ahead, the challenge is not only to refine these technologies, but also to deploy them at the scale required to make a meaningful impact. This will require coordinated efforts across sectors, supported by policy frameworks and investment in infrastructure. It will also require continued innovation, as researchers seek to improve performance and reduce costs.

In this context, the evolution of gas–liquid contactor design represents a critical frontier. By rethinking how gases and liquids interact within these systems, it is possible to unlock new levels of efficiency and scalability. Spray-based technologies, with their combination of simplicity and adaptability, are well positioned to play a significant role in this transformation.

Ultimately, the success of carbon capture will depend on our ability to bridge the gap between theory and practice. It will depend on whether we can take promising concepts and turn them into reliable, deployable systems. The research described here offers a glimpse of how this can be achieved, combining rigorous scientific analysis with a clear focus on real-world application.

As the world moves toward a low-carbon future, innovations like these will be essential. They remind us that progress is not only about new discoveries, but also about reimagining existing systems in ways that make them more effective and more accessible. In the case of carbon capture, this reimagining may well determine how quickly and how successfully we can reduce emissions at the scale required.