Decarbonisation Technology February 2026 Issue

fouling and corrosion across the system. With lower wall temperatures on the solvent side and shorter residence times, K°Flex enables more reliable, cleaner, and longer-lasting operation. Further heat exchangers needed in CCS process Further important heat exchangers are needed in the absorption CCS plant, including the overhead condenser, the water cooler for the direct contact cooler, and downstream compressor coolers. Additional heat

Kettle-type reboiler

KºF lex reboiler

Up to 75% weight & footprint saving

Figure 4 Comparison of Kelvion K°Flex vs kettle-type reboiler

The common heat exchanger type for reboilers in industry is shell and tube. In solvent-based systems, the kettle-type shell and tube heat exchanger is often seen. It is reliable and well- known, but is also big and heavy (see Figure 4 ). When developing large-scale CCS projects, project developers face several challenges. First, the number of reboilers needed to be put around the column can be impractically high. When more than four units are required, the space around the column becomes congested, and the vapour return piping becomes complex. Second, more project developers are seeking modularisation of their systems, which requires more compact, lower-weight heat exchangers. The answer is a fully welded PHE, such as the Kelvion K°Flex, which combines the advantages of shell and tube and PHE technologies in a single device, making it an excellent solution as a solvent reboiler. Its modular design is based on embossed stainless-steel plates, welded together in pairs to form flow channels. On the tube side of the plate pair, straight, tube-like channels are formed, allowing high flow rates with minimal pressure drop. The opposite side, or wave side, features a wave-shaped embossing that induces turbulence and enhances heat transfer efficiency. Beyond the benefits of saved space and weight, K°Flex’s advanced design minimises solvent degradation, significantly reducing

exchangers may be needed, depending on the specific plant arrangement. Typical types in these positions are shell and tube heat exchangers, PHEs, and air coolers. Central air-based cooling systems In most CCS plants, the thermal energy from the flue gases is not completely reused for other purposes. Often, an air-based central cooling system is installed on site, and an ambient air- based cooling system is generally a dry, adiabatic or wet type. In a dry cooling system, air coolers are used. The cooling media, mostly water or a water-glycol mixture, flow within the tubes and are cooled by the ambient air. There should be a temperature offset of at least 5K in relation to the dry bulb temperature for a dry cooling system. In cases where ambient air conditions are high and pure dry cooling cannot be realised, air coolers can be equipped with an adiabatic system, such as a spray, pad, or hybrid system. Depending on the size of the plant, the amount of waste heat, and other relevant factors, there are two directions to consider. The first option is dry, adiabatic, or hybrid cooling based on V-type standard coolers. The second is to use ACHE, which are by nature more customised, feature larger fans, and meet higher requirements, such as API 661, if needed. If sufficient water for cooling purposes is available, a purely wet cooling system using a