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Adsorption Equilibrium and Kinetics of Methanol Vapor on Zeolites NaX, KA, and CaA and Activated Alumina

Xiao, Yonghou, He, Gaohong, Yuan, Mingpu
Industrial & engineering chemistry process design and development 2018 v.57 no.42 pp. 14254-14260
adsorbents, adsorption, aluminum oxide, catalysts, diffusivity, methanol, models, process design, purification methods, steam, zeolites
Methanol vapor as a contaminant presented in industrial streams leads to catalysts deactivation. Therefore, it needs deep removal with adsorption technique. The isotherms and effective diffusion coefficients of methanol vapor are essential to design the purification process. The equilibrium sorption of methanol steam on commercial zeolites NaX, KA, and CaA and activated alumina were tested using an intelligent gravimetric analyzer, respectively. The equilibrium experiments were carried out at 303.2 K and pressures of up to 19.6 kPa, and the results obtained were fitted with the Dubinin–Astakhov (D-A) model. Moreover, the diffusion of methanol vapor in the adsorbents was investigated, and the effective diffusion coefficients were obtained with fitting the Fick diffusion model. The adsorbents are compared on the basis of adsorption capacities for methanol steam, and the descending order of zeolites is NaX > CaA > KA > Al₂O₃. The sorption equilibrium experimental results of methanol steam on NaX, KA, and CaA agree well with D-A isotherm model, while it is not very well consistent on Al₂O₃. The equilibrium adsorption capacities of methanol vapor are consistent with the effective diffusion coefficients on the adsorbents.