CALCULATION OF BINARY ADSORPTION EQUILIBRIA: HYDROCARBONS AND CARBON DIOXIDE ON ACTIVATED CARBON

摘要

The calculations are based on pure component and multicomponent models for adsorption equilibria which have been derived in details elsewhere. The pure component model was derived on the basis of Vacancy Solution Theory (VST) and the Non-Random-Two-Liquid (NRTL) model. The NRTL equation is capable of describing equilibria in immiscible liquid systems; consequently, it is expected to be able to describe strongly non-ideal adsorbates. The multicomponent model was derived by combining the pure component model with Adsorbate Solution Theory (AST) thus yielding a model for non-ideal multicomponent adsorption equilibria. In this work activity coefficients in the adsorbate phase are calculated by means of the Spreading-Pressure-Dependency (SPD) model. Parameter estimation has been performed in two steps: 1. The five parameters of the pure component model were estimated for each adsorbate using experimental pure component data. The five parameters are (subscript i refers to adsorbate and v to vacancies): a_(iv), the nonrandomness constant and the temperature dependent parameters Q_~∞(T), the amount of adsorbed i at saturation b_i(T), Henry's law constant Υ_(iv)(T), Υ_vi(T), parameters in the NRTL equation. 2. The shape factors s_1, s_2 and the cross-lateral interaction parameter β_(ij) in the SPD model were estimated using experimental data for binary adsorption.