Reaction kinetics of ammonia absorption/desorption of metal salts

• The thermodynamic properties were obtained without the pseudo equilibrium behavior.
• The dependence of absorption/desorption rate on pressure and temperature was investigated.
• The kinetic parameters for an empirical kinetic model were determined.

The reversible reactions between ammine magnesium complex and ammonia are studied by volumetric method and the heterogeneous reaction kinetic analysis at a grain level. The influence of heat and mass transfer limitations at a pellet level on the overall absorption/desorption rate is sufficiently minimized with the reactive block and the micro-channel reactor. The pseudo equilibrium for Mg(NH3)2Cl2 + 4NH3 ⇔ Mg(NH3)6Cl2 is not observed in the volumetric measurement. The kinetic parameters for the kinetic model are identified by the experimental data. The analysis reveals that the heterogeneous temperature or pressure distribution in the grain is the predominant factor on the overall absorption/desorption rate.