Kazuaki Nakagawa

Carbon dioxide absorption by lithium orthosilicate in a wide range of temperature and carbon dioxide concentrations

The CO 2 absorption properties of lithium orthosilicate (Li 4 SiO 4 ) were evaluated and were compared with those of Li 2 ZrO 3 .

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.

CO/sub 2/ collection technique from fuel gas

TOSHIBA developed a unique ceramic which can absorb about 400 times as much CO/sub 2/ as their volume and can repeat CO/sub 2/ absorption and releasing. Combining both the fuel reforming technique and CO/sub 2/ absorption technique using this ceramic, it becomes an effective way for the realization of the CO/sub 2/ collection technique from the fuel gas at the stage before combustion.

Stabilized matrix for molten carbonate fuel cell

For commercialization of molten carbonate fuel cell (MCFC) power plants, the most important factors are MCFC performance and life. The performance and life of an MCFC depend on the electrolyte loss and gas crossover due to the matrix degradation, such as LiAlO/sub 2/ particle growth during cell operation and the matrix cracking at the initial heat-up stage. In order to suppress the matrix degradation, we fabricated a stabilized matrix with /spl alpha/-LiAlO/sub 2/ as the electrolyte support material and with long /spl alpha/-Al/sub 2/O/sub 3/ fibers as the reinforcement. We assembled the cell with the stabilized matrix. The performance of the cell is stable for 7000 hours. We consider that the matrix degradation, such as the particle growth during cell operation and matrix cracking, has not occurred in this cell.