The key criteria and considerations for a three-phase (G/L/L) separator are (1) what are the estimated volumetric flow rates for the three phases and (2) the 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.