Systems and methods for processing a C.sub.3 and C.sub.4 hydrocarbon mixture have been disclosed. The C.sub.3 and C.sub.4 hydrocarbon mixture is separated to remove propane from C.sub.4 hydrocarbons. The resulting C.sub.4 hydrocarbons are then processed in an isomerization unit to produce additional isobutane. The isobutane of the isomerization unit effluent is dehydrogenated in a dehydrogenation unit to produce isobutene. The resulting isobutene is reacted with an alkanol to produce an alkyl tert-butyl ether.

Systems and methods for processing a C.sub.3 and C.sub.4 hydrocarbon mixture have been disclosed. The C.sub.3 and C.sub.4 hydrocarbon mixture is separated to remove propane from C.sub.4 hydrocarbons. The resulting C.sub.4 hydrocarbons are then processed in an isomerization unit to produce additional isobutane. The isobutane of the isomerization unit effluent is dehydrogenated in a dehydrogenation unit to produce isobutene. The resulting isobutene is reacted with an alkanol to produce an alkyl tert-butyl ether.

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.

Methods and systems for steam cracking a mixed butane containing feed stream are disclosed. The feed stream includes n-butane and isobutane. The disclosed methods and systems entail splitting the feed into an enriched n-butane fraction and an enriched isobutane fraction. The enriched n-butane fraction is provided to the cracking furnaces, which yield the olefin products and also yield C4 species. The C4 species are partially hydrogenated and provided as a reactant feed to an alkylation reaction. The enriched isobutane fraction is also provided to the alkylation reaction, whereby high value alkylate product is produced. The disclosed methods and systems have increase olefins (especially ethylene) yield because the feed to the cracking process is enriched in n-butane. The economics are also improved because high value alkylate product is produced from a portion of the isobutane.

Methods and systems for steam cracking a mixed butane containing feed stream are disclosed. The feed stream includes n-butane and isobutane. The disclosed methods and systems entail splitting the feed into an enriched n-butane fraction and an enriched isobutane fraction. The enriched n-butane fraction is provided to the cracking furnaces, which yield the olefin products and also yield C4 species. The C4 species are partially hydrogenated and provided as a reactant feed to an alkylation reaction. The enriched isobutane fraction is also provided to the alkylation reaction, whereby high value alkylate product is produced. The disclosed methods and systems have increase olefins (especially ethylene) yield because the feed to the cracking process is enriched in n-butane. The economics are also improved because high value alkylate product is produced from a portion of the isobutane.

The invention is directed to a process to prepare propylene from a hydrocarbon feed comprising pentane by contacting the hydrocarbon feed with a heterogeneous cracking catalyst as present in one or more fixed beds thereby obtaining a cracked effluent. The heterogeneous catalyst comprises a matrix component and a molecular sieve comprising framework alumina, framework silica and a framework metal selected from the group of Zn, Fe, Ce, La, Y, Ga and/or Zr. Propylene is isolated from the cracked effluent.

The invention is directed to a process to prepare propylene from a hydrocarbon feed comprising pentane by contacting the hydrocarbon feed with a heterogeneous cracking catalyst as present in one or more fixed beds thereby obtaining a cracked effluent. The heterogeneous catalyst comprises a matrix component and a molecular sieve comprising framework alumina, framework silica and a framework metal selected from the group of Zn, Fe, Ce, La, Y, Ga and/or Zr. Propylene is isolated from the cracked effluent.

Systems and methods for isomerizing n-butane to form isobutane are disclosed. A segmented reactor system is used to isomerize n-butane. The segmented reactor system comprises a segmented reactor that includes a first catalyst bed and a second catalyst bed separated by a first heat exchanger. The catalyst in the first catalyst bed does not contact the catalyst in the second catalyst bed. During the exothermic process of isomerizing n-butane, the first heat exchanger extracts heat from an intermediate product flowing from the first catalyst bed to the second catalyst bed to improve the conversion rate of n-butane.

Systems and methods for isomerizing n-butane to form isobutane are disclosed. A segmented reactor system is used to isomerize n-butane. The segmented reactor system comprises a segmented reactor that includes a first catalyst bed and a second catalyst bed separated by a first heat exchanger. The catalyst in the first catalyst bed does not contact the catalyst in the second catalyst bed. During the exothermic process of isomerizing n-butane, the first heat exchanger extracts heat from an intermediate product flowing from the first catalyst bed to the second catalyst bed to improve the conversion rate of n-butane.