Wide applicability of analogical models coupled with hysteresis effect for halide/ammonia working pairs

As the effective way for utilizing low-grade thermal energy, chemisorption technologies have been widely researched by establishing various phenomenological models and analogical models. But the existing kinetic models have the disadvantages of complexity or narrow adaptability, and they also cannot adapt to the serious hysteresis phenomena found in recent years. In order to obtain wide-adaptable kinetic models of halide/ammonia for material level, in this paper the sorption and desorption kinetics which consider hysteresis effects of halide/ammonia with MnCl2/NH3 and CaCl2/NH3 as representative working pairs are studied. Results show that the fitting parameters of the three-parameter models are unstable, while the two-parameter linear model is a relatively reliable candidate model with the recommended reaction rates (ks/kd) and reaction orders (m) varying widely for different halides (MnCl2 and CaCl2), different reaction stages (Ca4-8 and Ca2-4) and different reaction directions (sorption and desorption). The validation of model presents that the established linear model considering hysteresis effect could adapt to different halide/ammonia working pairs and predict the kinetic property. Furthermore, the model adaptability to large scale occasions is researched through the experiments with 200 g composited sorbent in a sorption reactor, which indicate that the established kinetic models and parameters can simulate the total reaction time accurately with the deviation of 10.4% and 3.9% under 0 °C and 10 °C evaporating temperature, respectively. © 2020 Elsevier B.V.