Carbon Dioxide Post-Combustion Capture: Solvent Technologies Overview, Status and Future Directions

One of the most promising approaches to tackle the high emission rate of carbon dioxide is the use of Carbon Capture and Storage (CCS) technology. This technology aims at capturing carbon dioxide from power stations and other industrial facilities, compressing, and then transporting it to underground storage locations. Three technological routes for carbon capture from power plants exist: pre-combustion, post-combustion and oxycombustion. Pre-combustion is the removal of the carbon element from fuel gas prior to combustion [1]. This process takes place in Integrated Gasification Combined Cycle (IGCC) plants and operates at high pressures for high concentrations of CO2. IGCC plants still face several obstacles to commercialization. For instance, only two IGCC demonstration plants are in operation in the power sector in the United States. The second option is oxy-fuel combustion, which involves the use of high purity oxygen (instead of air) for fuel combustion and produces a CO2/H2O stream from which water is easily condensed [2]. However, the air (or nitrogen-oxygen) separation step is considered a bottle-neck for this process due to its energy intensiveness and high capital and operational costs. Finally, postcombustion capture involves a highly energy intensive nitrogen-carbon dioxide separation step [3]. As an end-of-pipe technology, this process is easier to implement compared to the other capture routes. In this chapter, the focus will be placed on post-combustion capture technology due to its high maturity, ability to be retrofitted to existing power plants and operational flexibility in switching between capture and no-capture modes [4].