Dividing wall distillation column and method for refining vinylidene dichloride by using same

A method for refining vinylidene dichloride comprising a step of fractionally distilling a crude product containing vinylidene dichloride using a dividing wall distillation column for fractional distillation of a crude product containing vinylidene dichloride (1,1-dichloroethylene),

• wherein the dividing wall distillation column comprising:
• a main column having a dividing wall, a condenser, and a reboiler,
• wherein the main column includes, based on a vertical cross section, a feed zone and an outflow zone partitioned on one side and the other side, with the dividing wall being interposed therebetween, a column top zone adjacent to an upper end of the dividing wall and a column bottom zone adjacent to a lower end,
• wherein the dividing wall divides a liquid stream into a first stream falling through the feed zone and a second stream falling through the outflow zone, when a liquid stream condensed in the column top zone falls to the column bottom zone, and
• wherein at least a part of the dividing wall is positioned to be deflected in the direction of the feed zone so that a quantitative ratio of the first stream to the second stream satisfies the following Equation 1:
• N1/(N1+N2)=X (1)
• wherein, N1 is a flow rate of the first stream, N2 is a flow rate of the second stream, and X is 0.3 to 0.5, and
• wherein the dividing wall includes,
• a first wall adjacent to the column top zone and relatively adjacent to an inner wall of the feed zone on the basis of a virtual vertical plane that symmetrically partitions the main column,
• a second wall adjacent to the column bottom zone and located on the vertical plane, and
• a third wall forming a level difference in an extended form between the first wall and the second wall.