Abstract
For the expansion of ammonia utilization, the fast absorption and fixation of NH3 is required to prevent damage from leakage. In this study, ammonia absorption with NiCl2 is the focus for NH3 fixation, because it can absorb ammonia in low concentration with high fixation capacity. Thermogravimetric studies were performed on NH3 absorption with NiCl2 at temperatures of 303–383 K and NH3 pressures of 23–84 kPa. As a result, it was found that initial particle sizes smaller than 355 µm had little influence on the NH3 absorption rate. Ammonia absorption with NiCl2 was enhanced with increasing temperature and NH3 pressure, but it proceeded more slowly at 383 K compared to at 363 K. The absorption rate expression was determined for the NiCl2/NiCl2·6NH3 reaction based on the grain model. The determined reaction rate constant and reaction order concerning NH3 pressure had different temperature dependence between 303–323 K and over 323 K. The estimated conversion reasonably agreed with the experimental data.
