The Landscape of Solid Sorbents in CCUS

As the urgency to decarbonize our society accelerates, the scientific community is navigating a complex landscape of materials that have potential in addressing the challenges of carbon capture. From metal-organic frameworks (MOFs) to zeolites and activated carbons, researchers are exploring diverse avenues to find materials that can efficiently and sustainably capture CO₂. The efficacy of these materials, however, hinges not only on their capacity to absorb CO₂ but also on their performance under realistic and dynamic process conditions.

Challenges in Material Evaluation

Effectively evaluating materials for CCUS demands a multifaceted approach. Beyond assessing the quantity of CO₂ a material can absorb, researchers must consider a spectrum of factors such as working capacity, kinetics, selectivity, stability, thermal properties, and cost considerations. A recent collaboration between researchers at Imperial College in London and industry experts resulted in the formulation of best practices, emphasizing the need for complete characterization metrics and in-process relevant conditions.

Gravimetric Precision and Real-Time Monitoring

At the heart of the DVS Carbon lies its gravimetric basis, leveraging a highly sensitive symmetric SMS Ultrabalance. This microbalance facilitates direct measurements of changes in sample mass with unparalleled precision, reaching down to the microgram level. This real-time monitoring capability with sub-second resolution is foundational in understanding the dynamic nature of material interactions with CO₂ under varying conditions.

Dynamic Flow System for Realistic Conditions

The DVS Carbon’s dynamic flow system is a cornerstone of its capability to simulate realistic process conditions. By precisely controlling CO₂ concentration, flow rates, temperature and humidity, researchers can mimic diverse scenarios, from Direct Air Capture with low CO₂ concentrations to post-combustion conditions with high temperature and CO₂ gas concentrations. This flexibility is instrumental in obtaining insights into material performance that align with real-world applications.

Innovation in Sensor Technology

To enhance its performance, the DVS Carbon incorporates patented speed-of-sound sensors. This sensor technology, specially redesigned for this purpose, enables the high-accuracy measurement of carbon dioxide concentrations in the gas phase. Operating within a range of up to 100 percent CO₂ by volume, these sensors contribute to the instrument’s ability to capture nuanced changes during absorption and desorption processes.

In the following sections, we will delve into case studies that exemplify the DVS Carbon’s capabilities in evaluating materials under realistic conditions, as well as exploring other novel instrumentations pioneering new capabilities in this space, offering a glimpse into their potential impact on advancing carbon capture technologies.

Hydration and Carbonation Kinetics:

The experiments revealed that the hydration and carbonation kinetics of CaO are highly influenced by the level of humidity. The higher the humidity, the faster the reactions, showcasing the material’s sensitivity to water content. This insight is critical for assessing the material’s performance in realistic flue gas conditions where varying humidity levels are encountered.

Water Uptake and Thermal Regeneration:

The recorded water isotherms provided valuable data on the material’s affinity for water. The subsequent thermal regeneration step demonstrated the feasibility of completely transforming CaO to calcium hydroxide, confirming the full extent of the process.

Real-World Implications:

Understanding the kinetics and dependencies on humidity allows researchers to tailor the use of CaO in direct air capture scenarios. The ability to control and optimize the carbonation process is crucial for the material’s practical application in industrial settings.

Understanding how 13X zeolite interacts with these gases informs the design of CO2 capture systems tailored for post-combustion settings, thereby contributing to more sustainable and environmentally friendly energy production. In essence, the study of 13X zeolite underscores the tangible contributions of materials science in the global endeavor to reduce carbon emissions and transition toward cleaner energy sources.

Competitive Adsorption of CO₂ and Water

Single-Component Isotherms:

The isotherms revealed that 13x exhibits a high uptake for both CO₂ and water. However, even at low concentrations, water seems to saturate the material more rapidly than CO₂. This highlights the competitive nature of water and its potential to impact the material’s performance in post-combustion scenarios.

Multi-Component Breakthrough Experiments:

The breakthrough experiments provided a dynamic perspective, showing that water and CO₂ compete for adsorption sites. The total uptake of CO₂ was significantly reduced when introduced simultaneously with water, emphasizing the need to consider water’s impact in practical flue gas conditions.

Real-World Implications:

These findings underscore the importance of understanding the water-CO₂ competition when evaluating materials like 13x for post-combustion CO₂ capture. The DVS Carbon and BTA Frontier tandem offers a holistic view, enabling researchers to gauge the material’s performance in complex industrial settings.

Simultaneous Gas Introduction:

Like the DVS Carbon, the BTA Frontier allows the introduction of multiple gases simultaneously, mimicking real-world conditions where various gases compete for adsorption sites.

Dynamic Breakthrough Curves:

By continuously monitoring the mass balance over a packed bed, researchers gain insights into how different gases interact with the material over time.

Integration of Breakthrough Curves:

The breakthrough curves obtained can be integrated to quantitatively determine the total and individual uptakes of each gas.

Realistic Industrial Conditions:

The instrument enables experiments under conditions representative of industrial settings, providing actionable data for material evaluation.

Customizable Experimental Parameters:

Researchers can tailor experiments to specific industrial scenarios by adjusting parameters such as gas concentrations, flow rates, and temperature.

Complementary to Gravimetric Analysis:

When coupled with gravimetric instruments like the DVS Carbon, the BTA Frontier offers a holistic approach to understanding material behavior.

Whether it’s elucidating the interplay between CO2 and water vapor in post-combustion flue gas or exploring the dynamics of other gas mixtures, the BTA Frontier adds a layer of depth to the understanding of material performance under complex industrial conditions.