A phenomenological analysis has been developed of an olefin/paraffin gaseous separation process in a liquid-membrane contacting system comprising polymeric non-porous gas-separation membranes and aqueous silver nitrate flowing within an absorber/stripper cascade. New analytical solutions of the problem, taking into account the reversible chemical reaction of silver ions and olefins, are presented and numerically computed. Calculated dependences of the desorber productivity and selectivity are compared with experimental data. It is shown that the model can be used for a rough estimation of the system＇s behavior. In particular, it is shown that with an increase in the liquid-membrane flow rate productivity increased rapidly and then stabilized. Selectivity decreased with an increase in the liquid membrane flow rate. It was shown further that concentration profiles in the absorber system could be distinguished between equilibrium and non-equilibrium states.