Steam cracking of hydrotreated and hydrogenated hydrocarbon feeds

An integrated process for converting a hydrocarbon feedstock having components boiling above about 100° C. into steam cracked products, which process comprises:

• a) passing said hydrocarbon feedstock in the presence of a hydrogen source and a first hydrotreating catalyst through a first hydrotreating zone at an elevated temperature and pressure to reduce the levels of organic sulfur and/or nitrogen compounds contained therein, where the first hydrotreating catalyst comprises a component selected from the group consisting of Group VIB metals, Group VIB oxides, Group VIB sulfides, Group VIII metals, Group VIII oxides, Group VIII sulfides and mixtures thereof, supported on an amorphous carrier,
• b) passing the product from said first hydrotreating zone to a second hydrotreating zone wherein said product is contacted at elevated pressure and a temperature in the range of from about 200° C. to about 550° C. with a hydrogen source and a second hydrotreating catalyst comprising one or more hydrotreating components selected from the group consisting of Group VIB metals, Group VIB oxides and Group VIB sulfides, where the Group VIB metal is selected from the group consisting of tungsten, molybdenum and mixtures thereof, Group VIII metals, Group VIII oxides and Group VIII sulfides, where the Group VIII metal is selected from the group consisting of nickel, cobalt and mixtures thereof, and mixtures thereof, supported on an acidic carrier selected from molecular sieves having a pore diameter greater than about six angstroms admixed with an inorganic oxide binder selected from the group consisting of alumina, silica, silica-alumina and mixtures thereof, to effect substantially complete decomposition of organic sulfur and/or nitrogen compounds contained in the product from the first hydrotreating zone,
• c) passing the product from said second hydrotreating zone to an aromatics saturation zone wherein said product is contacted at elevated pressure and a temperature in the range of from about 200° C. to about 370° C. with a hydrogen source and an aromatics saturation catalyst comprising one or more Group VIII noble metal hydrogenation components on a zeolitic support comprising a modified Y-type zeolite having a unit cell size between 24.18 and 24.35 Å and a SiO2/Al2O2 molar ratio of at least 25,
• d) passing the product from said aromatics saturation zone to a steam cracking zone wherein said product is contacted with steam at temperatures greater than about 700° C., and
• e) recovering hydrogen and C1-C4 hydrocarbons, steam cracked naphtha, steam cracked gas oil and steam cracked tar therefrom, wherein the amount of steam cracked gas oil produced is reduced by at least about 30 percent and the amount of steam cracked tar produced is reduced by at least about 40 percent, basis the starting hydrocarbon feedstock which has not been subjected to hydrotreating and aromatics saturation.