Graphical method to obtain multicomponent adsorption equilibria from intermediate breakthrough curve plateaus

•Method proposed for diluted (constant velocity) and isothermal cases.•Adsorption breakthrough curves are integrated to capacity curves.•Capacity curves allow to obtain adsorbed quantities in equilibrium with intermediate zones.•Equilibria were obtained from breakthrough curves of alcohols on all-silica beta zeolite.•Two, instead of one, equilibrium points could be obtained from one breakthrough curve. Adsorption mixture equilibrium data remains challenging to obtain. An established technique is the adsorption breakthrough experiment where the final adsorbed capacities are determined. A graphical method to obtain adsorbed amounts from the intermediate plateaus in the breakthrough curves is proposed in this work. The method is proposed for isothermal, diluted breakthrough tests. Via an integrated capacity curve, the intermediate regions can be extrapolated to extract additional equilibrium points beyond the final state without the need for a multicomponent model. If the column is preloaded, the extra equilibrium points can correspond to multicomponent mixtures as multiple species can have non-zero intermediate concentration plateaus. The method is demonstrated on various simulated examples and then applied on breakthrough data from non-preloaded and preloaded columns of all-silica beta zeolite for diluted methanol/ethanol and diluted ethanol/isobutanol mixtures.