Adsorption Equilibrium and Dynamics of C4 Olefin/Paraffin on π‐Complexing Adsorbent

Abstract

Ag+ ion impregnated clay as a newly developed adsorbent was studied for 1‐butene separation from n‐butane. Equilibrium adsorption isotherms of pure components were measured at the temperature range from 25°C to 100°C and pressure up to 1200 mmHg. Experimental data of n‐butane and 1‐butene were correlated with various isotherm models. The best selectivity was shown at 80°C. Equilibrium capacities for 1‐butene and n‐butane at 80°C and 900 mmHg were 0.92 and 0.31 mmol/g, respectively. The average heats of adsorption for n‐butane and 1‐butene were found to be 6.6 and 13.3 kcal/mol, respectively. Diffusion of 1‐butene and n‐butane on this sorbent was fast, with 100% uptake reached within 15 min. The IAS model with Toth isotherm for pure component gave the best prediction results for both the n‐butane and 1‐butene compared to the other models used in the study. Binary adsorption equilibrium was well predicted by the Ideal Adsorbed Solution (IAS) model. The equilibrium adsorption ratio of 1‐butene/n‐butane in binary system was 14.87 and its selectivity was 6.71 at 80°C and 900 mmHg, when the mole fraction of 1‐butene in gas phase was 0.689. Experimental breakthrough curves were well predicted by a mathematical model, and the curves were steep enough to separate 1‐butene from n‐butane. Thus, it can be noted that Ag+ ion impregnated clay can be applied to the adsorptive separation of C4 olefin/paraffin.