How does Carbon Capture work?
Carbon capture refers to the process of capturing carbon dioxide (CO2) emissions from various sources, such as power plants and industrial facilities, in order to prevent them from being released into the atmosphere. This technology primarily involves three main steps: capturing CO2, transporting it to a storage location, and storing it underground or utilizing it in different ways.
Long answer
Carbon capture works through a series of processes aimed at capturing and managing CO2 emissions. The first step is the capture phase, which can be achieved using three different methods: post-combustion, pre-combustion, and oxy-fuel combustion.
In post-combustion capture, CO2 is removed from flue gases after the fossil fuels have been burnt and energy has been generated. Various techniques such as absorption using chemical solvents or adsorption using solid materials are employed.
In pre-combustion capture, fuel is converted into a mixture of hydrogen (H2) and carbon monoxide (CO), commonly called syngas. The CO is then reacted with steam via a process called steam reforming to generate H2 for energy production while simultaneously producing a concentrated stream of CO2 that can be captured more easily.
Oxy-fuel combustion involves burning fossil fuels with pure oxygen instead of air. As a result, the flue gas predominantly consists of CO2 and water vapor. The water vapor is condensed out to yield concentrated CO2 that can be captured.
After capturing the CO2 through one of these methods, the next step is transportation. Typically, pipelines are used to transport the captured CO2 away from its source to dedicated storage locations. This transportation may involve compressing or liquefying the captured gas for efficient movement over longer distances.
The final step in carbon capture is the storage or utilization of the captured CO2. Geological storage involves injecting compressed CO2 into deep underground rock formations such as depleted oil or gas fields, saline aquifers, or coal beds. The formations act as secure storage sites where the CO2 can be stored for long periods, minimizing its release into the atmosphere.
Additionally, carbon capture and utilization (CCU) methods explore ways to convert CO2 into valuable products, such as chemicals and building materials. CCU techniques include using CO2 as a raw material in industrial processes or converting it into synthetic fuels, plastics, or concrete. These approaches not only mitigate emissions but also provide opportunities to commercialize the captured CO2.
While carbon capture technology holds the potential to reduce greenhouse gas emissions significantly, there are challenges to address regarding cost-effectiveness, energy requirements of the capture processes, and ensuring long-term storage integrity. Nonetheless, ongoing research strives to improve efficiency and optimize these techniques for widespread implementation in mitigating climate change.