Separation of gases on the membranes finds all more widely used. One of the promising directions is the use of membranes in equipment of air separation units for purification neon-helium mixture from the nitrogen. This will allow to refuse the reflux condenser that is especially actual due to the advent of air separation units with limited issuance of liquid nitrogen. The mathematical model with a high degree of accuracy predicts the process characteristics baromembrane separation of multicomponent gas mixtures over wide ranges of operation modes. The computing algorithm for schemes with direct-flow and counter-flow management process withnin the membrane were formulated. The results of the calculations for the case of air and the multicomponent mixture of rare gases were observed. Experimental data was compared with the results obtained, which confirmed their good coincidence.