Reproducibility of Lithium Silicate Pellets in N2 Atmosphere

A lithium silicate (Li 4 SiO 4 ) absorbent has been developed as a new CO 2 absorbent at high temperatures, which emits CO 2 at temperatures above 993 K in pure CO 2 at 101 kPa. This temperature is approximately 200 K lower than that for well-known CaO. It was used in CH 4 steam reforming experiments and higher CH 4 conversion was observed for a mixture of a catalyst and an Li 4 SiO 4 pellet, than for a catalyst alone, at around 873 K. In this study, the emission temperature and reproducibility of an Li 4 SiO 4 pellet (5 mm, spherical) in N 2 was examined from the viewpoint of building a high-efficiency H 2 production system, since the CO 2 emission temperature is lower than that in pure CO 2 . The pellet completely emitted CO 2 within 1 h at 873 K, and within 0.5 h at 923 K, and showed high reproducibility, exhibiting almost the same absorption property for 5 cycles.