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Till the last drop Deep Cut Vacuum Design and Experience Cesare Somaini
Baretti® Your worldwide partner
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading
Baretti
Bottom of Barrel Upgrading
Deep-cut Vacuum
Process Design
Mechanical Design
Critical Zones Analysis
Conclusions
Contents
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading
• Baretti is an Italian private company created on 1890. It still belongs to the founding family.
• Baretti has been providing Mass Transfer Technologies and Components since 1950.
• Baretti designs and manufactures all kind of columns internals and provide relevant spare parts, technological upgrades and site services.
Baretti® Your worldwide partner
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading Bottom of Barrel Upgrading
• Heavier crudes resulting in more residue per bbl of feed
• Increasing demand of middle distillates and declining demand of residual fuels
• Tightening of product specification to meet environmental regulations
• Atmospheric Residue and VGO conversion balances these divergent trends.
• Several separation, thermal and catalytic processing schemes are available.
• The revamp of existing vacuum columns to cut deeper the long residue is an attractive option.
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading
• Deep-cut vacuum target is the maximum HVGO TBP cut point with specified qualities.
Deep-cut Vacuum
• HVGO specifications depends of downstream units.
• Catalytic units are the most sensitive to HVGO quality. (Ni + V, CCR, Asphaltenes, etc.).
• Deep-cut vacuum technology is on market since almost 30 years.
• The severe operating conditions are still challenging the process and the internals design.
• Baretti introduced new features improving operability and reliability of the internals for this technology
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading Vacuum Internals - Structured Packing
• Structured packing is the most used internal in vacuum towers because of its very low pressure drop.
• The lower is the pressure drop, the deeper is the crude cut point increasing distillate yield.
• Vacuum are characterized by high vapor and low liquid loads : perfect conditions for structured packing.
The low liquid load forms a uniform film on the structured packing surface.
The high vapor load ripples the liquid film increasing surface area and mass transfer.
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading Vacuum Internals - Structured Packing
Structured packing is available in several materials, thickness, surface treatment, specific surface area and angle of inclination to match a wide spectrum of applications and services
Incr
easi
ng C
apac
ity
Increasing Efficiency
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading Deep-cut Vacuum
A reduction of 1 mmHg of flash zone pressure gives an increase of 0.3% in the distillates yield.
An inaccurate design has important economic consequence. Reliability and mechanical integrity strongly contribute to profitability
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading Process Design
Actual performance assessment and characterization of feed are essential to:
• Build a reliable tower model
• Review critical zones: • Transfer Line • Flash Zone • Wash Zone • PA Zones • Stripping zone
• Estimate HVGO quality
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading Mechanical Design
1950 Main Italian
Refinery
2016 Main ME
Refinery
CDU Column ID 4.000
mm CDU
Column ID 10.000
mm
80.000 bbl/d
400.000 bbl/d
1950
Mech Specs
+7 times area
2016
Mech. Specs
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading Mechanical Design
ID 8 meters and 16 meters
Two phase feed inlet, Nozzle Ø = 3.6 m.
Diameter 16 m.
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading Wash Zone
• Mechanical design of internals minimizing liquid stagnation zones is recommended.
• Once it starts, it will quickly grow and invade all the bed.
• Wash Zone failure is due to coking and/or mechanical damages.
• Wash zone coking can be extremely severe limiting the cycle length.
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading
Column ID 10.000 mm Area 78 m2
Support Ring 120
mm
Area 3,8 m2
5 % area is not properly
washed
Wash Zone
Column Ring ID Width
mm mm 800 - 1.300 40
1.301 - 2.400 50 2.401 - 3.600 70 3.601 - 6.100 80 6.101 - 7.600 90
> 7.600 100-120
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading Wash Zone - Baretti® Anti Clogging Solutions
Baretti® AC Support Ring
• No obstructions to liquid and vapor flow • Very low hold-up • Maximum section opening • Very robust in case of upsets • Cycle length extended to 5 years
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading Wash Zone - Baretti® Anti Clogging Solutions
Baretti® AC Beams in combination with AC Support Ring or stand alone, assures: • Minimum flow resistance • Minimum hold-up • Optimum vapor distribution
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading
Baretti® ACVG Baretti ACVG valves has been developed specifically for extra fouling resistance.
Specific design to:
Stripping Zone
• Improve liquid flow on tray (Jet effect) • Maximize opening size to reduce the possibility of
clogging • Easy to replace in case of clogging
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading Transfer Line & Flash Zone
• HVGO quality depends on vapor distribution and entrainment to the wash zone
• The transfer line, the flashing feed inlet device and the above chimney tray must be designed as an integrated system to assure an optimal vapor distribution and minimum entrainment to the wash zone.
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading Pump-around Empty Zone
• The use of empty sections in heat transfer zones allows a further reduction of the pressure drop.
• A lower flash zone pressure increases production of gasoil.
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading Conclusion
• Revamps of Vacuum to Deep-cut are a quick execution and short pay-back alternative for Bottom of Barrel upgrade.
• A reliable Deep-cut Vacuum design requires process and mechanical knowledge of columns’ internals combined with advanced simulation systems.
• Baretti Anti Clogging features increase reliability preventing wash zone coking, resulting in extended operating cycle and reduced unplanned shutdown.
• Baretti is an experienced partner with the technical knowledge and the organization to execute Vacuum Deep-cut revamps
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading
Questions? Thank you for your attention
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading HVGO Quality - FCC Catalyst poisoning
• More Gas can limit WGC capacity • More Coke can limit coke burning capacity
o Higher regenerator. Temperature o Lower cat/oil ratio o Loss in conversion
• CCR coke maker • Nickel coke and gas makers • Vanadium destroys the zeolites reducing catalyst activity
Higher catalyst consumption to maintain activity Equipment constraints
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6th TRC-JCCP/Idemitsu International Symposium Bottom of Barrel Upgrading HVGO Quality - HC Catalyst deactivation
• HC catalyst deactivation is inevitable but the rate at which it occurs varies greatly depending of feed characteristics.
• Coke deposit on catalyst is the main cause of deactivation.
• Resins, asphaltenes & other poly-aromatics in the feed are coke precursor (CCR and C7 Insoluble).
• Control of PNA in feed & HPNA management are required to lengthen the operating cycle and maintain conversion.
• Catalyst deactivation is compensated with RX temperature increase. Lower deactivation rate, lower operational costs.
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