Systems and methods for the production of a high purity isoamylene product. The isoamylene in a mixed hydrocarbon stream may initially be converted to TAME via etherification, and a subsequent decomposition of the TAME may result in a high purity isoamylene stream with very low impurities that is suitable for a variety of petrochemical applications, such as for use in the production of fragrances, pesticides, peroxides, polymer antioxidants, UV stabilizers and hydrocarbon resins.

Saturation of a pyrolysis stream is achieved while managing exotherms. The pyrolysis stream is split into at least two feed streams for at least two saturation reactors. The process may split the hydrogen stream into at least two streams for the at least two saturation reactors. A recycle stream may also be provided to manage the exotherm. The feed may comprise at least 5 wt % aromatics.

Saturation of a pyrolysis stream is achieved while managing exotherms. The pyrolysis stream is split into at least two feed streams for at least two saturation reactors. The process may split the hydrogen stream into at least two streams for the at least two saturation reactors. A recycle stream may also be provided to manage the exotherm. The feed may comprise at least 5 wt % aromatics.

Device and process for converting a feedstock of aromatic compounds, in which the feedstock is notably treated using a fractionation train (4-7), a xylenes separating unit (10) and an isomerization unit (11), and in which a pyrolysis unit (13) treats a second hydrocarbon-based feedstock, produces a pyrolysis effluent feeding the feedstock, and produces a pyrolysis gas comprising CO, CO2 and H2; a WGS water gas shift reaction section (50) suitable for treating the pyrolysis gas and for producing a WGS gas enriched in CO2 and in hydrogen; a CO2 aromatization reaction section (52) suitable for: at least partly treating the WGS gas to produce a hydrocarbon effluent comprising aromatic compounds, and feeding the feedstock with the hydrocarbon effluent.

Device and process for converting a feedstock of aromatic compounds, in which the feedstock is notably treated using a fractionation train (4-7), a xylenes separating unit (10) and an isomerization unit (11), and in which a pyrolysis unit (13) treats a second hydrocarbon-based feedstock, produces a pyrolysis effluent feeding the feedstock, and produces a pyrolysis gas comprising CO, CO2 and H2; a WGS water gas shift reaction section (50) suitable for treating the pyrolysis gas and for producing a WGS gas enriched in CO2 and in hydrogen; a CO2 aromatization reaction section (52) suitable for: at least partly treating the WGS gas to produce a hydrocarbon effluent comprising aromatic compounds, and feeding the feedstock with the hydrocarbon effluent.

A method of producing a fuel additive includes: passing a raffinate stream comprising C4 hydrocarbons through a hydrogenation unit, forming a first process stream; passing the first process stream through an extractive distillation unit, forming a C4 olefin stream; passing the C4 olefin stream through a stripper column, forming a purified C4 olefin stream; and forming the fuel additive by passing the purified C4 olefin stream through a hydration unit.

A method of producing a fuel additive includes: passing a raffinate stream comprising C4 hydrocarbons through a hydrogenation unit, forming a first process stream; passing the first process stream through an extractive distillation unit, forming a C4 olefin stream; passing the C4 olefin stream through a stripper column, forming a purified C4 olefin stream; and forming the fuel additive by passing the purified C4 olefin stream through a hydration unit.

A nonlimiting example method for producing a diesel boiling range composition comprises: oligomerizing an ethylene stream to a C4+ olefin stream in a first olefin oligomerization unit, wherein the C4+ olefin stream contains no greater than 10 wt% of methane, ethylene, and ethane combined in a first oligomerization; and wherein the ethylene stream contains at least 50 wt% ethylene, at least 2000 wppm ethane, no greater than 1000 wppm of methane, and no greater than 20 wppm each of carbon monoxide and hydrogen; oligomerizing the C4+ olefin stream and a propylene/C4+ olefin stream in a second oligomerization unit to produce an isoolefinic stream; wherein at least a portion of the isoolefinic stream is used to create the diesel boiling range composition.

A nonlimiting example method for producing a diesel boiling range composition comprises: oligomerizing an ethylene stream to a C4+ olefin stream in a first olefin oligomerization unit, wherein the C4+ olefin stream contains no greater than 10 wt% of methane, ethylene, and ethane combined in a first oligomerization; and wherein the ethylene stream contains at least 50 wt% ethylene, at least 2000 wppm ethane, no greater than 1000 wppm of methane, and no greater than 20 wppm each of carbon monoxide and hydrogen; oligomerizing the C4+ olefin stream and a propylene/C4+ olefin stream in a second oligomerization unit to produce an isoolefinic stream; wherein at least a portion of the isoolefinic stream is used to create the diesel boiling range composition.

Device and process for the conversion of a feedstock of aromatic compounds, in which the feedstock is treated notably by means of a fractionation train (4-7), a xylene separation unit (10) and an isomerization unit (11), and in which a pyrolysis unit (13) treats a second hydrocarbon feedstock, produces a pyrolysis effluent feeding the feedstock, and produces a pyrolysis gas comprising CO, CO.sub.2 and H.sub.2; a reverse water gas shift RWGS reaction section (50) treats the pyrolysis gas and produces an RWGS gas enriched in CO and in water; a fermentation reaction section (52) treats the RWGS gas enriched in CO and in water, to produce ethanol and recycle the ethanol to the inlet of the pyrolysis unit.