Apparatuses and methods for separating butene-1 from a mixed C4 feed

A process for recovering 1-butene from a feed stream comprising n-butane, isobutane, 1-butene and 2-butene, wherein the feed stream does not contain substantial amounts of isobutene or butadiene, the process comprising:

• introducing the feed steam into a first side of a distillation column, the distillation column further comprising a top, a bottom and a center dividing wall extending from the top to the bottom and dividing the column into a first side and a second side, the first side comprising an overhead area and a bottoms area, the second side comprising an overhead area and a bottoms area;
• taking off an isobutane stream from the overhead area of the second side of the column;
• taking off a 1-butene stream from the bottoms area of the second side of the column;
• taking off a combination 2-butene and n-butane stream from the bottoms area of the first side of the column;
• and
• introducing at least partially condensed overhead vapor from the first side of the column as a second feed stream to the second side of the column.

A process for recovering 1-butene from a feed stream comprising n-butane, isobutane, 1-butene and 2-butene, wherein the feed stream does not contain substantial amounts of isobutene or butadiene, the process comprising:

• introducing the feed steam into a first side of a distillation column, the distillation column further comprising a top, a bottom and a center dividing wall extending from the top to the bottom and dividing the column into a first side and a second side, the first side of the column being isolated from the second side of the column, the first side comprising an overhead area and a bottoms area, the second side comprising an overhead area and a bottoms area,
• taking off an isobutane stream from the overhead area of the second side of the column and condensing the isobutane stream;
• taking off a 1-butene stream from the bottoms area of the second side of the column;
• taking off a combination 2-butene and n-butane stream from the bottoms area of the first side of the column;
• introducing at least partially condensed overhead vapor from the first side of the column as a second feed stream to the second side of the column;
• and
• introducing at least a portion of the at least partially condensed overhead from the second side of the column and at least a portion of the 1-butene stream to the overhead area of the first side of the column as reflux.

A dividing wall fractional distillation column for recovering 1-butene from a feed stream comprising n-butane, isobutane, 1-butene and 2-butene, wherein the feed stream does not contain substantial amounts of isobutene or butadiene, comprising:

• an outer vessel enclosing an internal cylindrical volume and comprising a top and a bottom;
• a dividing wall extending vertically through the vessel and dividing the vessel into adjacent the first and second sides, the first side comprising an overhead area and a bottoms area, the second side comprising an overhead area and a bottoms area;
• the first side comprising a first feed inlet for introducing the feed stream into the first side of the vessel, a first bottoms outlet for removing a 2-butene/butane stream from the bottoms area of the first side of the vessel, and the overhead area of the first side of the vessel being in communication with a second feed inlet disposed in the second side of the vessel;
• the second side comprising the second feed inlet for introducing overhead vapor from the first side of the vessel to the second side of the vessel, a second bottoms outlet for removing 1-butene from the bottoms area of the second side of the vessel and a second side overhead outlet for removing an isobutane stream from the overhead area of the second side of the vessel.