Preförbränningsinfångning

Preförbränningsinfångning, often abbreviated as PCC, is a process used in some combustion systems to capture carbon dioxide (CO2) before it is released into the atmosphere. This technology is a form of post-combustion capture but is applied to the fuel itself or the process gases prior to full combustion. The core idea is to separate CO2 from the fuel or the flue gas stream at an earlier stage, which can potentially lead to lower energy penalties and higher capture efficiencies compared to traditional post-combustion methods.

There are several approaches to PCC. One method involves gasifying the fuel, such as coal or biomass, into a synthesis gas (syngas) composed primarily of carbon monoxide (CO) and hydrogen (H2). The CO is then reacted with steam in a water-gas shift reaction to produce more H2 and CO2. The CO2 can then be separated from the syngas, often through methods like amine scrubbing or physical absorption. The remaining hydrogen-rich gas is then used as fuel for combustion, producing predominantly water vapor and significantly reducing CO2 emissions.

Another variant of PCC involves using oxygen instead of air for combustion, a process known as oxy-fuel combustion. This produces a flue gas with a much higher concentration of CO2 and water vapor, making the separation of CO2 more straightforward and energy-efficient. However, the requirement for an air separation unit to produce oxygen adds to the overall cost and complexity of the system. PCC technologies are being developed and demonstrated as a means to mitigate greenhouse gas emissions from industrial sources and power plants.