Hideo Uemoto

Novel CO2 Absorbents Using Lithium-Containing Oxides

Publisher Summary Lithium-containing oxides have been developed for application as a series of novel CO 2 absorbents. The absorption is ascribed to the mechanism whereby lithium oxide in the crystal structure reacts reversibly with CO 2 . Among these absorbents, lithium orthosilicate (Li 4 SiO 4 ) reacts with CO 2 at higher reaction rate at around 500°C. Furthermore, the emission was performed at a much lower temperature than that of CaO. This temperature enables Li 4 SiO 4 to be used repeatedly in pure CO 2 . Moreover, the absorption also proceeds at ambient temperature in an atmospheric environment. This characteristic suggests numerous possible applications such as air cleaners or cartridges. In this study, CO 2 absorption properties of lithium orthosilicate and its contemplated applications were investigated. From the viewpoint of preventing global warming, there is a growing need to reduce the amount of emission of carbon dioxide (CO 2 ). For that purpose, saving of energy, improvement of conversion efficiency, and development of alternative energy sources and separation of CO 2 are promising countermeasures. Regarding separation of CO 2 , it is thought to be effective to remove CO 2 from the high-temperature fuel gas of power plants. However, most CO 2 removal techniques have poor heat-tolerance. The authors have developed a novel CO 2 separation technique by employing the chemical reaction of lithium zirconate (Li 2 ZrO 3 ) with CO 2 . The application to power plants is expected to be the most effective for combating global warming. To achieve continuous absorption, a system in which several reactors are changed sequentially constitutes a basic approach.