Abstract: A process for separation and treatment of a naphtha feedstock to increase overall octane in a gasoline blending pool by reducing or removing the normal pentane in the feedstock. The feedstock is passed into a divided wall column having an undivided top portion, an undivided bottom portion and a wall dividing a middle portion into two sections. The intermediate faction can include either all normal pentane, which can be utilized on other processes, or it can include a mixture of normal pentane and C6 hydrocarbons, which can be isomerized in an isomerization zone to increase the octane and then passed to a gasoline blending pool.

Abstract: Dividing wall fractional distillation columns and methods of operating these columns with greater flexibility, especially in terms of the ability to adjust the composition of the heartcut, intermediate or sidecut product fraction, are described. In particular, this composition may be advantageously “biased” toward higher or lower molecular weight components, depending on operating needs. Changes in feedstock composition may also be managed more effectively. These benefits are obtained by varying the flow rate of vapor and liquid to each side of the dividing wall. The vapor flowrate rising from an undivided portion of the column interior below the dividing wall is varied to the feed and/or product sections on opposite sides of the dividing wall. Also, the liquid flowrate falling from an undivided portion of the column interior above the dividing wall is varied to the feed and/or product sections on opposite sides of the dividing wall.

Abstract: Dividing wall fractional distillation columns and methods of operating these columns with greater flexibility, especially in terms of the ability to adjust the composition of the heartcut, intermediate or sidecut product fraction, are described. In particular, this composition may be advantageously “biased” toward higher or lower molecular weight components, depending on operating needs. Changes in feedstock composition may also be managed more effectively. These benefits are obtained by varying the flow rate of vapor and liquid to each side of the dividing wall. The vapor flowrate rising from an undivided portion of the column interior below the dividing wall is varied to the feed and/or product sections on opposite sides of the dividing wall. Also, the liquid flowrate falling from an undivided portion of the column interior above the dividing wall is varied to the feed and/or product sections on opposite sides of the dividing wall.