Enclosed Partition Dividing Wall (EPDW) distillation columns and methods of using EPDW distillation columns are disclosed. The EPDW distillation column includes a column body, a dividing wall, and a wall cap attached to the dividing wall. The wall cap, a portion of column body bound to the wall cap and/or an EPDW surrounding wall, and the dividing wall form an enclosed partition wall rectification section with an opening at the bottom such that a portion of components from the bottom of the column body is separated in the EPDW rectification section.

Enclosed Partition Dividing Wall (EPDW) distillation columns and methods of using EPDW distillation columns are disclosed. The EPDW distillation column includes a column body, a dividing wall, and a wall cap attached to the dividing wall. The wall cap, a portion of column body bound to the wall cap and/or an EPDW surrounding wall, and the dividing wall form an enclosed partition wall rectification section with an opening at the bottom such that a portion of components from the bottom of the column body is separated in the EPDW rectification section.

A method for separating and refining 1-butene with a high purity and a high yield from a raffinate-2 stream. The method includes: feeding raffinate-2 to a first distillation column; obtaining heavy raffinate-3 from a lower part of the first distillation column; recovering an upper part fraction containing 1-butene from an upper part of the first distillation column; feeding the upper part fraction containing 1-butene to a second distillation column; recovering a first lower part fraction rich in 1-butene from a lower part of the second distillation column and light raffinate-3 from an upper part of the second distillation column. Heat of the upper part fraction recovered from the upper part of the first distillation column is fed to the lower part of the second distillation column through a first heat exchanger. Thus, 1-butene is obtained with high purity and high yield while maximizing an energy recovery amount by double-effect distillation.

A method for separating and refining 1-butene with a high purity and a high yield from a raffinate-2 stream. The method includes: feeding raffinate-2 to a first distillation column; obtaining heavy raffinate-3 from a lower part of the first distillation column; recovering an upper part fraction containing 1-butene from an upper part of the first distillation column; feeding the upper part fraction containing 1-butene to a second distillation column; recovering a first lower part fraction rich in 1-butene from a lower part of the second distillation column and light raffinate-3 from an upper part of the second distillation column. Heat of the upper part fraction recovered from the upper part of the first distillation column is fed to the lower part of the second distillation column through a first heat exchanger. Thus, 1-butene is obtained with high purity and high yield while maximizing an energy recovery amount by double-effect distillation.

A method for the production of a fuel additive includes passing a hydrocarbon stream comprising crude mixed C4 hydrocarbons through a first hydrogenation unit to produce a first product stream; passing the first product stream from the first hydrogenation unit to a methyl tert-butyl ether synthesis unit forming methyl tert-butyl ether and a byproduct stream; passing the byproduct stream through a first distillation unit to separate the byproduct stream into a first 1-butene stream, an isobutane stream, and a 2-butene and n-butane stream; forming a second product stream by passing the 2-butene and n-butane stream to a selective conversion unit; passing the second product stream into a second distillation unit to form an n-butane stream and a second 1-butene stream; passing the second 1-butene stream to a fuel additive production unit; and passing the first 1-butene stream to the fuel additive production unit to form the fuel additive.

A method for the production of a fuel additive includes passing a hydrocarbon stream comprising crude mixed C4 hydrocarbons through a first hydrogenation unit to produce a first product stream; passing the first product stream from the first hydrogenation unit to a methyl tert-butyl ether synthesis unit forming methyl tert-butyl ether and a byproduct stream; passing the byproduct stream through a first distillation unit to separate the byproduct stream into a first 1-butene stream, an isobutane stream, and a 2-butene and n-butane stream; forming a second product stream by passing the 2-butene and n-butane stream to a selective conversion unit; passing the second product stream into a second distillation unit to form an n-butane stream and a second 1-butene stream; passing the second 1-butene stream to a fuel additive production unit; and passing the first 1-butene stream to the fuel additive production unit to form the fuel additive.

A process can be used for purifying a hydrocarbon stream containing at least Cx alkanes, Cx olefins, low boilers such as Cx−1 hydrocarbons, and high boilers such as Cx+1 hydrocarbons, with x=3 or 4. The process involves separating off low boilers and separating off high boilers, wherein the separating-off of high boilers is performed in the presence of hydrogen and hence a hydrogenation of the olefins present takes place.

A process can be used for purifying a hydrocarbon stream containing at least Cx alkanes, Cx olefins, low boilers such as Cx−1 hydrocarbons, and high boilers such as Cx+1 hydrocarbons, with x=3 or 4. The process involves separating off low boilers and separating off high boilers, wherein the separating-off of high boilers is performed in the presence of hydrogen and hence a hydrogenation of the olefins present takes place.

A process for converting isobutane to propylene. The process including dehydrogenating isobutane to produce a mixed product stream comprising isobutane and isobutene, skeletal isomerizing the mixed product stream comprising isobutane and isobutene to convert isobutene to n-butenes including 1-butene and 2-butenes and to recover a skeletal isomerization reaction product comprising isobutane, isobutene, butadiene, 1-butene, and 2-butenes. The process further including fractionating the skeletal isomerization reaction product, isomerizing the 1-butene contained therein to 2-butenes, recovering an overhead fraction comprising isobutane, a side draw fraction comprising isobutane and isobutene, and a bottoms fraction comprising 2-butenes, and combining the bottoms fraction with ethylene and converting the ethylene and 2-butenes to produce a reaction effluent comprising propylene.

A process for converting isobutane to propylene. The process including dehydrogenating isobutane to produce a mixed product stream comprising isobutane and isobutene, skeletal isomerizing the mixed product stream comprising isobutane and isobutene to convert isobutene to n-butenes including 1-butene and 2-butenes and to recover a skeletal isomerization reaction product comprising isobutane, isobutene, butadiene, 1-butene, and 2-butenes. The process further including fractionating the skeletal isomerization reaction product, isomerizing the 1-butene contained therein to 2-butenes, recovering an overhead fraction comprising isobutane, a side draw fraction comprising isobutane and isobutene, and a bottoms fraction comprising 2-butenes, and combining the bottoms fraction with ethylene and converting the ethylene and 2-butenes to produce a reaction effluent comprising propylene.