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Energy Transition
Carbon capture methods and their heat transfer challenges
As the world intensifies its efforts to combat climate change, carbon capture and storage( CCS) technologies have become crucial in reducing greenhouse gas emissions. This article delves into the heat transfer challenges associated with three prominent CCS methods: amine-based absorption, cryogenic carbon capture, and direct air capture and Kelvion’ s heat exchange solutions. Each of these methods presents unique engineering hurdles that must be overcome to enhance their efficiency and effectiveness. By exploring the latest advancements and solutions in heat exchanger technology, we aim to shed light on how these challenges are being addressed, paving the way for more sustainable and scalable carbon capture solutions.
By Roy Niekerk, Global Director Application Engineering, Kelvion
Post-combustion The amine wash process is one of the most established and commercially available carbon capture technologies, widely used in industries. Several companies and research institutes offer aminebased carbon capture solutions, for example:
• Mitsubishi Heavy Industries,‘ KM CDR’ process
• Aker Solutions, Aker CO 2 capture process
• Shell, Cansolv CO 2 capture technology
• Fluor, Econamine FG + ™ process
Most amine-based carbon capture technologies follow similar underlying principles of chemical absorption, though the solvents although proprietary names might vary( e. g., MEA, DEA, proprietary blends). They all rely on the same core concept of using amines to absorb CO 2 from gas streams. All absorption-based carbon capture systems, including those using amines, require multiple heat exchangers for the regeneration of the solvent, energy optimisation, and maintaining system efficiency. The captured CO 2 must be desorbed from the solvent using heat, which necessitates an efficient heat exchange process.
Flue gas heat recovery When amine systems are used after a gas or coal fired power plant, the flue gas must first be cooled before it can enter the amine system. Because of Henry’ s Law, absorption of gases into a liquid works better at lower temperatures. And amine solutions would degrade if temperatures get too high, which leads to fouling and corrosion in the amine system. The flue gas should typically enter the absorption column at 40 ° C to 60 ° C( 104 ° F to 140 ° F) [ 1 ]. The flue gas coming from a normal coal or gas fired power plant is at close to atmospheric pressure. One heat exchanger type that can be used here is tube bundles in rectangular flue gas duct as can be seen in Figure 1 below. There is a lot of freedom in the type of tube used. These can be any diameter, pitch and material suitable for the process. For instance, when it is expected that the cooling of the flue gas passes through the acid dew point, high allow materials can be applied to avoid corrosion issues. A technology that offers maximum efficiency is Kelvion’ s Rekuluvo / Rekugavo, which is a welded plate type. This
Figure 1: Process diagram amine system.
24 Heat Exchanger World April 2025 www. heat-exchanger-world. com