postforbrænding

Postforbrænding, or post-combustion capture, is a set of techniques used to remove carbon dioxide from exhaust gases after combustion has occurred. The term is used in Danish and other languages to describe the capture stage in carbon capture and storage (CCS) systems that treat flue gas from power plants and various industrial processes.

In a typical postforbrænding system, flue gas is cooled and cleaned, then passed through an absorber where CO2 chemically binds to solvents or is captured by solid sorbents. The most common approach uses amine-based solvents (for example monoethanolamine) to form a CO2-rich solution; CO2 is later released from the solvent by heating (regeneration) and compressed for transport to storage or utilization. Alternative approaches use solid sorbents such as zeolites, activated carbons, or other materials. The remaining gas has a substantially reduced CO2 concentration before release to the atmosphere.

Technologies employed include chemical absorption with liquids, physical solvent methods, and solid sorbent processes. Postforbrænding is particularly relevant for retrofitting existing plants, since it can treat high-volume flue gas without requiring major changes to combustion conditions. It is also compatible with a range of fuels and industrial processes that operate at atmospheric or near-atmospheric pressure.

Advantages of postforbrænding include the potential to retrofit current facilities and the ability to treat flue gas without changing the combustion process. Disadvantages focus on energy penalties associated with solvent regeneration, higher capital and operating costs, material degradation, and the need for transport and storage infrastructure for captured CO2.

Historically, postforbrænding has been a central focus of CCS research and pilot projects for several decades, with ongoing efforts to reduce costs and improve efficiency for broader commercial deployment. See also carbon capture and storage and related CCS technologies.