The basics for a three-phase (G/L/L) separator design require quantification of (1) the estimated volumetric flow rates for the three phases and (2) desired degree of separation. After defining (1) and (2), the physical properties should be obtained and the remaining design procedure follows that of a G/L separator. Separation of the two immiscible phases follows the standard design procedure for L/L separator and for reliability may be performed in a separate vessel for the L/L separation; handbooks on separator design providing guidance include Henry Kister’s Distillation Design and Philip Schweitzer’s Handbook of Separation Techniques for Chemical Engineers.