The continuous distillation design is favored by a multilevel network of expert systems. The goal of each expert system is the selection of the type of process performance, of the simulation methods needed, etc. A procedure of computer aided knowledge accumulation is suggested to facilitate the choice of process alternatives at different stages of continuous distillation scheme design. Mixtures with different types of phase diagrams have been analyzed. The efficiency of the procedure of computer aided knowledge accumulation strongly depends upon the criteria of choice of variants at each stage of design.