Introduction to Carbon Capture

Abstract

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.