604
The Chemistry and Technology of Petroleum
routed through the oil heater to prevent coking in the heater tubes. The outlet streams from both
heaters are fed to the bottom of the reactor.
The vertical reactor vessel is free of internal equipment and operates in a three-phase mode. The
solid additive particles are suspended in the primary liquid hydrocarbon phase through which the
hydrogen and product gases flow rapidly in bubble form. The reactor exit stream is quenched with
cold recycle hydrogen prior to the high-pressure separator. The heavy liquids are further reduced
in pressure to a hot medium-pressure separator and from there to fractionation. The spent additive
leaves with the heavy fraction and remains in the unconverted vacuum residue.
The vapor stream from the hot high-pressure separator is cooled stepwise to produce middle
distillate and naphtha that are sent to fractionation. High-pressure purge of low-boiling hydrocarbon
gases is minimized by a sponge oil circulation system. Product naphtha will be hydrotreated and
reformed, light gas oil will be hydrotreated and sent to the distillate pool, and the heavy gas oil will
be processed in the FCC and the pitch will be sold.
The additive, prepared from iron sulfate [Fe 2 (SO 4 ) 3 ], is used to promote hydrogenation and
effectively eliminates coke formation. The effectiveness of the dual-role additive permits the use
of operating temperatures that give high conversion in a single-stage reactor. The process maximizes the use of reactor volume and provides a thermally stable operation with no possibility of
temperature runaway.
The process also offers the attractive option of reducing the coke yield by slurrying the feedstock
with less than 10 ppm of catalyst (molybdenum naphthenate) and sending the slurry to a hydroconversion zone to produce low-boiling products (Kriz and Ternan, 1994).
22.3.3 enI slurry teCHnology ProCess
The Eni slurry technology process (EST process) was developed recently by Snamprogetti and
EniTecnologie, both companies of the Eni Group (DelBianco and Montanari, 2009). The process
operates in such a way as to permit the almost complete conversion of heavy petroleum feedstocks
into distillates and avoid the production of fuel oil and coke.
The heart of the process consists of a hydrotreating reactor in which the heavy feedstock
undergoes a hydrogenation treatment in relatively mild conditions (410°C–420°C, 760°F–790°F,
and 2400 psi), limiting the conversion per pass to distillates, but ensuring a satisfactory margin
of stability for the unconverted residue. The hydrotreatment is carried out in the presence of
several thousand ppm of a molybdenum-based catalyst finely dispersed in the liquid mass so as
to promote the upgrading reactions (metal removal, desulfurization, denitrogenation, and reduction of the carbon residue). The hydrotreated products leaving the hydrotreating unit are sent to
a fractionating section to recover the distillates. The unconverted residue from the bottom of the
fractionating column is then sent to a solvent deasphalting section (SDA) to recover the deasphalted and demetallized oil (DAO), while the asphaltene stream that contains all of the catalyst
is recycled to the hydrotreating section to be reprocessed together with additional fresh feedstock.
After recycling, a stationary steady-state condition is reached that makes it possible to obtain
almost total conversion levels.
22.3.4 (HC)3 ProCess
The (HC)3 process (high conversion/hydrocracking/homogeneous catalyst process) was developed
at the end of the 1980s by the Alberta Oil Sands Technology & Research Authority (AOSTRA)
and the Alberta Research Council (ARC). The upgrading reaction is carried out in the presence
of a catalyst defined as colloidal, formed in situ starting with oil-soluble precursors such as iron
pentacarbonyl or molybdenum 2-ethylhexanoate and, if necessary, by an aromatic diluent to prevent
precipitation (separation) of asphaltene constituents. The conversion product is fractionated under
vacuum, and the residue can be recycled.
The Chemistry and Technology of Petroleum
routed through the oil heater to prevent coking in the heater tubes. The outlet streams from both
heaters are fed to the bottom of the reactor.
The vertical reactor vessel is free of internal equipment and operates in a three-phase mode. The
solid additive particles are suspended in the primary liquid hydrocarbon phase through which the
hydrogen and product gases flow rapidly in bubble form. The reactor exit stream is quenched with
cold recycle hydrogen prior to the high-pressure separator. The heavy liquids are further reduced
in pressure to a hot medium-pressure separator and from there to fractionation. The spent additive
leaves with the heavy fraction and remains in the unconverted vacuum residue.
The vapor stream from the hot high-pressure separator is cooled stepwise to produce middle
distillate and naphtha that are sent to fractionation. High-pressure purge of low-boiling hydrocarbon
gases is minimized by a sponge oil circulation system. Product naphtha will be hydrotreated and
reformed, light gas oil will be hydrotreated and sent to the distillate pool, and the heavy gas oil will
be processed in the FCC and the pitch will be sold.
The additive, prepared from iron sulfate [Fe 2 (SO 4 ) 3 ], is used to promote hydrogenation and
effectively eliminates coke formation. The effectiveness of the dual-role additive permits the use
of operating temperatures that give high conversion in a single-stage reactor. The process maximizes the use of reactor volume and provides a thermally stable operation with no possibility of
temperature runaway.
The process also offers the attractive option of reducing the coke yield by slurrying the feedstock
with less than 10 ppm of catalyst (molybdenum naphthenate) and sending the slurry to a hydroconversion zone to produce low-boiling products (Kriz and Ternan, 1994).
22.3.3 enI slurry teCHnology ProCess
The Eni slurry technology process (EST process) was developed recently by Snamprogetti and
EniTecnologie, both companies of the Eni Group (DelBianco and Montanari, 2009). The process
operates in such a way as to permit the almost complete conversion of heavy petroleum feedstocks
into distillates and avoid the production of fuel oil and coke.
The heart of the process consists of a hydrotreating reactor in which the heavy feedstock
undergoes a hydrogenation treatment in relatively mild conditions (410°C–420°C, 760°F–790°F,
and 2400 psi), limiting the conversion per pass to distillates, but ensuring a satisfactory margin
of stability for the unconverted residue. The hydrotreatment is carried out in the presence of
several thousand ppm of a molybdenum-based catalyst finely dispersed in the liquid mass so as
to promote the upgrading reactions (metal removal, desulfurization, denitrogenation, and reduction of the carbon residue). The hydrotreated products leaving the hydrotreating unit are sent to
a fractionating section to recover the distillates. The unconverted residue from the bottom of the
fractionating column is then sent to a solvent deasphalting section (SDA) to recover the deasphalted and demetallized oil (DAO), while the asphaltene stream that contains all of the catalyst
is recycled to the hydrotreating section to be reprocessed together with additional fresh feedstock.
After recycling, a stationary steady-state condition is reached that makes it possible to obtain
almost total conversion levels.
22.3.4 (HC)3 ProCess
The (HC)3 process (high conversion/hydrocracking/homogeneous catalyst process) was developed
at the end of the 1980s by the Alberta Oil Sands Technology & Research Authority (AOSTRA)
and the Alberta Research Council (ARC). The upgrading reaction is carried out in the presence
of a catalyst defined as colloidal, formed in situ starting with oil-soluble precursors such as iron
pentacarbonyl or molybdenum 2-ethylhexanoate and, if necessary, by an aromatic diluent to prevent
precipitation (separation) of asphaltene constituents. The conversion product is fractionated under
vacuum, and the residue can be recycled.