수소경제 주목되는 기술·제품 69. 카본밸류의 ‘RPB 기반 CO2 포집 시스템’
Notable Technologies and Products in the Hydrogen Economy: Carbon Value’s RPB-Based CO2 Capture System
Development of Rotating RPB-Type Absorption and Regeneration Towers
Processing Capacity: The RPB-based system processes ten times the capacity compared to conventional column scrubbing systems.
Compact Size: It has been significantly downsized, making it possible to integrate as a carbon capture system on ships.
Joint Research with UNIST: Currently developing a pilot-scale capture device.
Simultaneous Development of Solvenmt: Alongside, the development of absorbents for carbon capture is underway.
At UNIST, Carbon Dioxide is Being Captured in a New Way
[UNIST Featuring Carbon Value's RPB-Based CO2 Capture System]
Currently, the most commercialized carbon capture technology is the tower-type carbon capture system. This method typically adopts a "scrubber" approach, which has a very large volume and cannot meet the requirements of the industrial sector. This highlights the need for smaller capture devices, contrasting with current trends.
As a result, attention is being drawn to compact carbon dioxide capture systems. Leading the charge in this area is Carbon Value. The company was born out of a thirst for "core design capabilities."
In South Korea, policies to foster heavy and chemical industries for rapid commercialization have led to the import and utilization of related technologies from abroad. Consequently, while the manufacturing capacity for delivery, quality, and cost is excellent, there is a weakness in core design capabilities.
[CARBON value & UNIST : Carbon Neutrality Demonstration and Research Center Joint Research Laboratory for Next-generation Technologies for Carbon Neutrality]
In contrast, overseas companies are operating in high-value sectors based on their core design capabilities. A representative company is Linde. Currently, Linde has accumulated extensive research experience in the energy sector, including hydrogen and carbon. Director Hankwon Lim of the Carbon Neutral Demonstration Research Center at UNIST, a founding member of Carbon Value, also developed core technologies as a development specialist at Praxair (now Linde) for about six years.
Since taking up his position as a professor, he has constantly thought about the need for core process design technology development in South Korea. Under the vision of forming a team similar to the development specialists at Praxair, Carbon Value was born.
UNIST focuses on research and projects, while Carbon Value concentrates on developing related core technologies. Sunbo Industries, a shipbuilding and marine equipment company in Busan, focuses on scaling these technologies.
Since the goal is to develop core technologies, expertise is crucial; thus, the team is made up of 20 individuals with master's and doctoral degrees, rather than undergraduates. Currently, they are working on the development of a carbon dioxide capture device based on core design.
Instead of simply purchasing foreign technology, they are committed to research based on a structure that includes software-based process simulations → lab-scale equipment manufacturing → validation through experiments → scaling-up design.
Director Lim expressed, “There is a company in Denmark called Haldor Topsoe that produces reformers. The people working there typically engage in company-related projects during their undergraduate or graduate studies before joining the company. This creates a strong connection between their work and studies, providing significant benefits to both the company and individuals. I hope that UNIST, Carbon Value, and Sunbo Industries can also become such a precedent.”
RPB-Based Carbon Dioxide Capture
[RPB Type CO2 Capture System]
The first talent following the UNIST-Carbon Value route is Dr. Byun Man-hee, who is currently serving as the Chief Technology Officer (CTO) at Carbon Value.
Dr. Byun stated, “Carbon Value's role is to scale up the core technologies discovered at the school level. We primarily act as a bridge to commercialize these technologies in a form that the industry can understand. Professor Hankwon Lim oversees the development of core technologies in the joint research lab. You can think of it as taking well-refined technologies and turning them into products. Our current technology theme focuses on carbon dioxide capture, and in the long term, on the utilization of carbon dioxide.”
Carbon Value is currently focusing on the ‘Rotating Packed-Bed (RPB) Type Carbon Dioxide Capture System.’ The capture of carbon dioxide relies on detailed technologies, such as the absorbent material and the key component known as packing material. The RPB system can be understood as a technology that applies low-energy rotational force to the packing material, significantly reducing the overall reactor size while maximizing carbon dioxide capture efficiency.
This technology can be widely applied not only to existing large-scale power plants but also to emerging energy production sectors such as fuel cell power sources and distributed hydrogen production technologies. Additionally, it is optimized for environments with severe space constraints, such as on ships, allowing shipowners to minimize opportunity costs while enabling environmentally friendly vessel operations.
Innovative Approaches to Absorption Tower and Regeneration Tower
[RPB's Absorption Tower]
“What you see here is the absorption tower. When the flue gas enters from this side, the absorbent is sprayed. Due to the rotation of the RPB, the carbon dioxide contained in the flue gas is captured more efficiently by the liquid absorbent. We can say that this liquid absorbent holds the carbon dioxide.”
This is Dr. Byun's explanation of the RPB system process. In reality, the packing material inside the RPB reactor can be seen continuously rotating.
“The absorbent passes through a heat exchanger before heading to the regeneration tower. Similarly, carbon dioxide is desorbed from the RPB reactor in the regeneration tower. The captured carbon dioxide transforms back into a gas and is released, while the absorbent is regenerated. The absorbent is then cycled back to the absorption tower to be sprayed again, continuing its circulation within the system.”
[RPB's Regeneration Tower]
Dr. Byun also added that a heat exchanger is necessary for more efficient process operation because each device within the system operates at different temperatures. For instance, the regeneration tower operates at 80 to 110°C, while the absorption tower operates at around 40°C, making it essential to recover heat for the heating process.
Between the absorption tower and the regeneration tower, there is an absorbent tank. Its purpose is to adjust the pump intensity to ensure the absorbent does not get blocked in the middle. If the absorbent supply is interrupted, it not only reduces efficiency but can also lead to safety accidents. This small RPB-type carbon dioxide capture system, about 0.5 meters in height, captures approximately 200 to 300 kg of CO2 per day.
The factory in Busan is currently working on scaling up the system to handle over 10 times this capacity. A pilot-scale demonstration is scheduled to take place within this year.
Securing Core Technology Through Hands-On Research
[Column Type CO2 Capture System]
The RPB system is being explored not only by Carbon Value but also by several companies worldwide, including the UK's Carbon Clean and Baker Hughes. However, what sets Carbon Value apart from these companies is its collaboration with academia and its joint research lab. This setup allows them to take technologies developed in school labs and apply them in the industry.
This means they can focus on core design technologies, such as the development of CO2 capture absorbents, optimized designs, and process engineering.
“I use the expression ‘kneading.’ Since the equipment is right next to us, we can come in and make adjustments and identify issues immediately. The know-how accumulated during the research process becomes the foundation for building larger equipment. All of this becomes assets that are reflected in design elements,”
said Director Hankwon Lim, who oversees the joint research lab.
Dr. Byun also agreed. The RPB system’s performance depends on many process variables, and even a slight change can alter the balance and performance, leading to different results.
The joint research lab also has a traditional tower-type CO2 capture system. This is a more conventional carbon capture technology that uses a vertically long reactor, and there are places where this technology is already in operation after successful demonstration. The issue, however, is its large size, which does not align with the demand for more compact CO2 capture systems. In operational environments, such as power generation using fuel cells or on ships, where space directly impacts profitability, there is a trend to minimize system volume.
“Don’t we need to verify that the RPB system outperforms the traditional tower-type system? Some suggested that we could just compare it to existing data. However, since we don’t know the exact conditions under which that data was obtained, we decided to build two devices ourselves to compare their performance under the same conditions,” explained Director Lim.
Director Hankwon Lim explained why the tower-type CO2 capture system was brought into the lab.
The approximately 2-meter high tower-type CO2 capture system in the lab captures about 20 kg per day, which is only one-tenth of the capture volume of the 0.5-meter high RPB type placed next to it. In other words, for the tower type to match the capture volume of the RPB, its size would need to be ten times larger.
The key to reducing the size of the RPB-type CO2 capture system lies in the RPB reactor itself. While the tower type captures CO2 by allowing the absorbent to flow and rely solely on gravity, the RPB reduces the size of the reactor by continuously rotating internal components to capture CO2.
[Container-Type Carbon Capture Systems Optimized for Ships]
Carbon Value aims to introduce this compact CO2 capture system to ships. As mentioned earlier, the tower type uses gravity, which necessitates a fixed height. Simply put, this means the capture unit would be exposed within the ship’s space. However, due to the nature of cargo ships, such large equipment is generally not welcomed.
Thus, Carbon Value has set the goal of placing the RPB system inside a container on the ship, thereby reducing wasted space. The RPB system to be installed will capture 2 to 10 tons of CO2 per day, and stacking multiple containers on a ship could potentially reduce around 10 to 50 tons. The technology readiness level (TRL) is currently at 6, and since the first stage of commercialization is TRL 7, it is expected to be on the market soon.
While the RPB reactor is essential, there have been many trials and errors in constructing the entire system. Each component, such as pipe thickness, tank size, pressure gauges, pump types, and CO2 meters, had to be individually designed.
Dr. Manhee Byun, the Chief Technology Officer and a key figure in the development of the RPB system, said
“To be honest, there are so many factors to consider that it’s difficult for a company to handle everything. Companies can’t afford to set aside commercialization projects. We managed to achieve this result because we could handle the equipment independently through the joint research lab. We are continuously communicating with the lab about how different process parameters, such as pressure, can affect the results and what design approach we should take.”
The Importance of Solvent
[Solvent Screening System]
Alongside RPB technology, there is another crucial factor: the solvent used for carbon dioxide capture. The performance of the RPB system varies depending on the solvent utilized. While there are commercially available solvents, they have certain drawbacks, which is why solvent development is also a key focus.
Current solvents require significant energy for regeneration and pose issues with the emission of other harmful byproducts. Additionally, the oxidation, degradation, and corrosion caused by the solvent's properties lead to maintenance concerns for the equipment, which needs improvement.
“One of the most common solvents is the primary amine group. However, when using amines in metal-based reactors, issues such as oxidation, degradation, and corrosion cause the equipment to wear down by a few millimeters each year. This can be a significant concern for businesses making substantial investments,” said Dr. Byun, highlighting the importance of solvent.
Carbon Value aims to develop a complete solution solvent that addresses technical issues such as oxidation, degradation, and corrosion. They plan to improve carbon dioxide capture performance while reducing the energy required for regeneration.
[CV-S3]
Currently, they have developed a solvent called ‘CV-S3.’ Compared to existing solvents, it not only enhances carbon capture efficiency but also reduces the energy required for regeneration by about 73%. Corrosion resistance has improved over tenfold. Carbon Value plans to send this solvent to a pilot testing facility in Denmark in the fourth quarter of this year to verify its performance on a larger scale. The test in Denmark will be ten times the scale of the current lab setup.
Dr. Byun explained, “The optimal product for solvents varies depending on the industry it is applied to. Carbon Value is diversifying its solvent portfolio to supply a total solution of RPB systems and solvents across various industries.”
A Hub of Industry-Academia Collaboration
[RPB Pilot-Scale System]
Developing the current RPB system was a process marked by extensive trial and error, involving over 100 revisions. The system was refined by continuously analyzing data from operational processes and making repeated adjustments.
“The biggest challenge was that no domestic companies were manufacturing RPBs, so we had to carve out our own path,” said Dr. Byun. The process involved designing the system on a computer, conducting fluid analysis, and completing process design. However, turning those designs into a physical product proved difficult, as there were hardly any companies in Korea that had the experience of developing products from basic design.
Despite these challenges, industry support helped fill the gaps. Sunbo Industries, in particular, played a crucial role. As a marine equipment company, it has the manufacturing capabilities to produce compact modules and units. Additionally, through a demonstration project to capture CO2 from fuel cell exhaust gas, conducted in collaboration with SK Eco Plant, Korea Southern Power, and Sunbo Unitech, scale-up is currently underway.
Dr. Byun expressed his gratitude, saying, “From basic design to turning new technology into a practical product, there are numerous challenges, and I’m thankful to the companies that supported us. The synergy between UNIST, our joint research lab, and Sunbo Industries, alongside the existing industry partners, was key to developing the RPB system we have today.”
For those interested in reading the original article, please refer to the source : (https://www.h2news.kr/news/articleView.html?idxno=12960)