1. Introduction to Carbon Capture

The capture of CO₂ is motivated by the forecasted change in climate as a result of the world’s dependence on fossil fuels for energy generation. Mitigation of CO₂ emissions is the challenge of the future for stabilizing global warming. The separation of CO₂ from gas mixtures is a commercial activity today in hydrogen, ammonia, and natural gas purification plants. Typically, the CO₂ is vented to the atmosphere, but in some cases, it is captured and used. The current primary uses of CO₂ include enhanced oil recovery (EOR) and the food industry (carbonated beverages). The traditional approach for CO₂ capture for these uses is solvent-based absorption. It is unclear whether this technology will be the optimal choice to tackle the scale of CO₂ emitted on an annual basis (~ 30 Gt worldwide). A new global interest in extending CO₂ capture to power plants is producing a dramatic expansion in R&D and many new concepts associated with clean energy conversion processes. The application of CO₂ capture technologies beyond concentrated sources is in view, but less tractable. The first and second laws of thermodynamics set boundaries on the minimum work required for CO₂ separation. Real separation processes will come with irreversibilities and subsequent inefficiencies taking us further from best-case scenarios. The inefficiency of a given process reveals itself in the form of operating and maintenance, and capital costs.