Processes and systems for petrochemical production integrating deep hydrogenation of hydrotreated diesel
Process scheme configurations are disclosed that enable deep hydrogenation of middle distillates. The hydrogenated middle distillates are processed in a steam cracker for conversion into light olefins. Feeds to the deep hydrogenation zone include diesel range streams from a diesel hydrotreating zone, a gas oil hydroprocessing zone, and/or a vacuum residue hydrocracking zone. The deep hydrogenation zone operates under conditions effective to reduce aromatic content in a diesel range feedstream from a range of about 10-40 wt % or greater, to a hydrogenated distillate range intermediate product having an aromatic content of less than about 5-0.5 wt %.
1. A process for petrochemical production comprising:
subjecting crude oil to atmospheric distillation to produce at least middle distillates;
subjecting the middle distillates from atmospheric distillation to hydrotreating to produce at least middle distillates having a reduced concentration of organosulfur and organonitrogen compounds;
subjecting all or a portion of middle distillates produced by hydrotreating to hydrogenation to hydrogenate aromatics contained in the middle distillates and produce hydrogenated middle distillates, wherein hydrogenation occurs in the presence of an effective quantity of a hydrogenation catalyst containing one or more active metal components selected from Pt, Pd, Re and a combination comprising at least two of Pt, Pd or Re, and the hydrogenation catalyst including a catalyst support comprising non-acidic amorphous alumina and about 0.1-15 wt % of a modified USY zeolite having one or more of Ti, Zr and/or Hf substituting aluminum atoms constituting the zeolite framework thereof; and
subjecting all or a portion of the hydrogenated middle distillates to thermal cracking in a steam cracking complex to obtain light olefins.
2. The process as in claim 1 , wherein
atmospheric distillation further separates naphtha, and further wherein all or a portion of the naphtha is thermally cracked in the steam cracking complex.
3. The process as in claim 2 , further comprising
subjecting at least a portion of the naphtha from atmospheric distillation to hydrogenation to saturate aromatics, and passing all or a portion of the hydrogenated naphtha fraction to thermal cracking.
4. The process as in claim 2 , wherein
the steam cracking complex comprises a common unit for cracking all or a portion of the naphtha from atmospheric distillation and all or a portion of the hydrogenated middle distillates from hydrogenation.
5. The process as in claim 2 , wherein
the steam cracking complex comprises plural sections for cracking all or a portion of the naphtha from atmospheric distillation and all or a portion of the hydrogenated middle distillates from hydrogenation separately based on boiling point characteristics.
6. The process as in claim 1 , wherein
hydrogenation occurs at a hydrogen partial pressure of about 50-150 barg.
7. The process as in claim 1 , wherein
hydrogenation occurs at a reaction temperature of about 250-400° C.
8. The process as in claim 1 , wherein
hydrogenation occurs at a liquid hourly space velocity values, on a fresh feed basis relative to the hydrogenation catalyst, of about 0.1-5.0 h −1 .
9. The process as in claim 1 , wherein
hydrogenation occurs at a hydrogen to oil feed ratio of about 100-1500 SLt/Lt.
10. The process as in claim 1 , wherein hydrogenation occurs
at a hydrogen partial pressure of about 50-150 barg;
at a reaction temperature of about 250-400° C.;
at a liquid hourly space velocity values, on a fresh feed basis relative to the hydrogenation catalyst, of about 0.1-5.0 h −1 ; and
at a hydrogen to oil feed ratio of about 100-1500 SLt/Lt.
11. The process as in claim 1 , wherein the middle distillates that are subjected to hydrogenation contain at least about 10 weight % aromatics, and wherein the hydrogenated middle distillates contains less than about 1 weight % aromatics.
12. The process as in claim 1 , wherein, prior to hydrogenation of the middle distillates,
the middle distillates are mixed with an excess of hydrogen gas in a mixing zone to produce a mixture of hydrogen-enriched middle distillates and undissolved hydrogen;
passing the mixture to a flashing zone wherein at least a portion of undissolved hydrogen is flashed, and obtaining a hydrogen-enriched middle distillates stream; and
subjecting the hydrogen-enriched middle distillates stream to hydrogenation.
13. A system for petrochemical production comprising:
an atmospheric distillation unit operable to separate at least middle distillates from a crude oil feedstock;
a hydrotreating zone operable to produce at least hydrotreated middle distillates from all or a portion of the middle distillates, wherein the hydrotreated middle distillates have a reduced concentration of organosulfur and organonitrogen compounds relative to the middle distillates;
a fixed-bed hydrogenation zone operable to produce hydrogenated middle distillates from all or a portion of the hydrotreated middle distillates, the hydrogenation zone containing an effective quantity of a hydrogenation catalyst, the hydrogenation catalyst
containing one or more active metal components selected from Pt, Pd, Re and a combination comprising at least two of Pt, Pd or Re, and
including a catalyst support comprising non-acidic amorphous alumina and about 0.1-15 wt % of a modified USY zeolite having one or more of Ti, Zr and/or Hf substituting aluminum atoms constituting the zeolite framework thereof; and
a steam cracking complex operable to thermally crack all or a portion of the hydrogenated middle distillates for production of light olefins.
14. The system as in claim 13 , wherein
the atmospheric distillation unit is further operable to separate naphtha, and further wherein the steam cracking complex is further operable to thermally crack all or a portion of the naphtha from the atmospheric distillation unit.
15. The system as in claim 14 , wherein
the steam cracking complex comprises a common unit for cracking all or a portion of the naphtha from the atmospheric distillation unit and all or a portion of the hydrogenated middle distillates from the hydrogenation zone.
16. The system as in claim 14 , wherein
the steam cracking complex comprises plural sections for cracking all or a portion of the naphtha from the atmospheric distillation unit and all or a portion of the hydrogenated middle distillates from the hydrogenation zone separately based on boiling point characteristics.
17. The system as in claim 13 , wherein
the atmospheric distillation unit is further operable to separate naphtha, the system further comprising a naphtha hydrogenation zone operable to produce hydrogenated naphtha from all or a portion of the naphtha separated from the atmospheric distillation unit, and wherein the steam cracking complex is further operable to thermally crack all or a portion of the hydrogenated naphtha from the naphtha hydrogenation zone.