Dividing wall distillation column for producing high purity acrylic acid and fractional distillation method using the same

A dividing wall distillation column comprising a condenser, a reboiler and a main column having a dividing wall,

• wherein the main column is divided into a column-top zone, an upper feed zone, an upper outflow zone, a lower feed zone, a lower outflow zone and a column-bottom zone,
• a raw material having an acrylic acid content of 90% by weight or more flows in a middle inflow plate in which the upper feed zone and the lower feed zone come in contact with each other, a low boiling point component flows out from the column-top zone, a high boiling point component flows out from the column-bottom zone, and a middle boiling point component flows out through a middle outflow plate in which the upper outflow zone and the lower outflow zone come in contact with each other,
• wherein the middle boiling point component is acrylic acid,
• wherein the number of plates provided respectively in the column-top zone, the upper feed zone, the upper outflow zone, the lower feed zone, the lower outflow zone and the column-bottom zone is in a range of 80 to 150% of a theoretical plate number, as calculated from a distillation curve,
• wherein a length of the dividing wall is in a range of 30 to 85% of the total theoretical plate number in the column-top zone, the upper feed zone, the lower outflow zone and the column-bottom zone, as calculated from the distillation curve,
• wherein a temperature of the column-top zone is in a range of 55 to 65° C. at a pressure of 4.666 kPa, in a range of 50 to 60° C. at a pressure of 3.333 kPa, and in a range of 60 to 70° C. at a pressure of 6.666 kPa,
• wherein a temperature of the column-bottom zone is in a range of 90 to 100° C. at a pressure of 4.666 kPa, in a range of 85 to 95° C. at a pressure of 3.333 kPa, and in a range of 93 to 103° C. at a pressure of 6.666 kPa, and
• wherein a temperature of the middle outflow plate is in a range of 73 to 83° C. at a pressure of 4.666 kPa, in a range of 70 to 80° C. at a pressure of 3.333 kPa, and in a range of 77 to 87° C. at a pressure of 6.666 kPa.