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  • www.albemarle.com

    Deactivation of Hydrotreating Catalysts in Different Reaction Zones of a

    VGO FCC-Pretreatment Reactor

    S. Eijsbouts, S. Mayo, L. Burns and G. AndersonXV F d A d l I d t i d R fi iXV Foro de Avances de la Industria de Refinacin Mexico City, September 2009

  • Contentswww.albemarle.com

    FCC PT iFCC-PT process overview

    Reaction zone concept

    Sampling and analysis goals

    Catalyst deactivation by coking and metals depositionCatalyst deactivation by coking and metals deposition

    2

  • FCC Pre-Treatment Improves FCC Product Quality and Operation www.albemarle.comProduct Quality and Operation

    Vacuum Gas Oils (VGO/HVGO) Naphtha

    FCC FeedHydrotreater

    (FCC-PT)

    ( )

    Coker Gas Oils (CGO/HCGO)

    Deasphalted Oils (DAO)

    Distillate

    Light Olefins

    Other Heavy Oils

    Hydrogen

    Fluid CatalyticCracking Unit

    (FCCU)

    Gasoline

    Light Cycle Oil

    Heavy Cycle / Slurry Oil

    FCC Feed Hydrotreater generates feed to the FCC to improveFCC Feed Hydrotreater generates feed to the FCC to improve the quality by removing contaminants and adding H2

    Generates some products directly; e.g., low S dieselp y; g ,Fluid Catalytic Cracker uses acid-catalyzed cracking to break heavy hydrocarbons down to gasoline and light cycle oils

    3

    Unit performs better on low contaminants, C/H ratio and N feed

  • FCC-PT Operates across a Wide Range of Conditions www.albemarle.comof Conditions

    Feed is heavy with high S N and C/H (i e high aromatic)Feed is heavy with high S, N and C/H (i.e. high aromatic) contents, metal contaminants (Ni, V, As, Si etc.), high ConCarbon (0-4 wt.%) and particulates (FeS, coke fines)

    Feed blend of VGO with lube extracts, coker stocks, resid, DAOsLHSV hr-1 0.5-1.2

    ppH2 bar 60-130

    H2/Oil Nl/l 250-500

    Temperature C 350-420 (EOR)

    HDS Target % 80

    HDN Target % 50

    4

    Different from ULSD and HC-PT (HDS/HDN conversion > 99%)

  • FCC-PT Catalyst Performance is Limited by Reaction Conditions www.albemarle.comby Reaction Conditions

    E th t ti t l t l h di iEven the most active catalysts only reach medium conversion levelsVery difficult feed treated at relatively low pressure/ppHVery difficult feed treated at relatively low pressure/ppH2In general, temperature is too low to remove all N, which is the main HDS inhibitor but too high to hydrogenatethe main HDS inhibitor, but too high to hydrogenate aromatics to a significant extent.Actual conditions (ppH2, ppH2S, ppNH3 and temperature)Actual conditions (ppH2, ppH2S, ppNH3 and temperature) change throughout the reactor

    5

  • Reaction Chemistry Changes at Each Point in the Catalyst System www.albemarle.comPoint in the Catalyst System

    n ure

    CatalystSystem S

    ulfu

    r

    Nitr

    ogen

    H2S

    NH

    3

    ppH

    2

    empe

    ratu

    Te

    6

  • A Conceptual Reaction Zone Model: FCC PT Operates in Zones 1 and 2 www.albemarle.comFCC-PT Operates in Zones 1 and 2

    Zone 1 Zone 2 Zone 3

    Sulfur content High Medium Low

    Nitrogen content High Medium Low Very LowZone 1 Polynuclear Aromatics High Medium Low Zero

    H2S in Gas 0 Medium High Highest

    NH3 in Gas 0 Medium Medium High

    Zone 23 g

    H2 in Gas High Medium Medium Low

    Main HDS ReactionMain HDS Inhibitor

    DirectH2S

    Direct + HydrognOrganic Nitrogen

    Hydrogenation

    Zone 3

    a S b to 2S O ga c t oge

    Main HDN/HDA ReactionMain HDN/HDA Inhibitor

    HydrognOrg. N, Aroms

    HydrogenationOrg. N, Aromatics

    HydrogenationAromatics

    HDS Reaction Rate Fast Slow Fast

    Reaction zones vary in length and position

    HDS Reaction RateHDN/HDA Reaction Rate

    FastVery Slow

    SlowSlow

    FastSlow-Medium

    7

    ULSD and Hydrocracking PT operate in all 3 zones

  • FCC-PT Catalystswww.albemarle.com

    y

    O ti i f b iFeed + H2Feed + H2

    Optimize performance by sequencing catalysts with functionality selected to match conditions and desired reactions in particularconditions and desired reactions in particular zones of the reactorGuard Bed

    Guard Bed

    Guard Bed: removes metal poisons (VGO demet), CCR and particulates; volume must be sufficient to protect the main bed catalystbe sufficient to protect the main bed catalyst

    Main Bed: depends on units operating Main

    Active Catalyst

    Main Active

    Catalysts strategy / conditions, focuses on HDS, HDN and aromatics saturation to meet unit objectives / constraints

    CatalystCatalysts

    8

    objectives / constraintsProducts + H2

  • Sampling of Commercial Reactorswww.albemarle.com

    p g

    Reactor fill between 15 800 mtReactor fill between 15-800 mtGuard bed and main bed may contain multiple catalystsSampling of specific parts of catalyst bed during unloading isSampling of specific parts of catalyst bed during unloading is difficult (gravity dumping)Optimum scenario: 1-5 samples of ca. 1 kg each taken per p p g pcatalyst layer ~ 0.005% material is sampledChemical and physical analysis:

    10-15g sample used ~ 0.000002% SEM and TEM:

    5 10 extrudates 50 100 mg used 0 00000001%5-10 extrudates ~ 50-100 mg used ~ 0.00000001%Representative sampling essential; confirm any unexpected results

    9

    results

  • Analysis Goalwww.albemarle.com

    y

    G d b d t l tGuard bed catalysts:Determine concentration and distribution of metal contaminantsDetermine coke contentDetermine coke content

    Main bed catalysts:Check for presence of metal contaminantsCheck for presence of metal contaminantsDetermine coke contentAssess the state of the active phase: MoS dispersionAssess the state of the active phase: MoS2 dispersion

    Challenging because there is so much going on

    10

  • Analysis of Different Catalyst Layers for Coke and Metallic Contaminants www.albemarle.comCoke and Metallic Contaminants

    Very significant catalystVery significant catalyst contamination in commercial operation deactivation30

    Coke Si Ni Fe V

    VGO-demet (160 m2/g):10 wt% MoO3 2 7 at/nm220

    25

    l (w

    t%)

    10 wt% MoO3 2.7 at/nm14 wt% C 42 at/nm28 wt% V2O5 3 at/nm28 wt% SiO 5 at/nm2

    15

    20

    nant

    Lev

    e

    8 wt% SiO2 5 at/nm2Deposited Ni ~ catalyst Ni 2.3 at/nm2 total Ni

    5

    10

    Con

    tam

    i

    Coke higher at inlet and outlet

    Higher feed C/H @ inlet

    0Demet Layer 1 Layer 2 Layer 3 Layer 4 Layer 5

    11

    Higher feed C/H @ inletHigher Rx Temp @ outlet

  • Analysis of Different Catalyst Layers for Coke and Metallic Contaminants www.albemarle.comCoke and Metallic Contaminants

    Metallic contaminants determine the

    id l f /Pore Volume residual surface area/ pore volume in regenerated samplesme

    (ml/g

    )

    ea (m

    2 /g)Pore Volume

    Surface Area

    regenerated samples Sintering may occur during regeneration

    ore

    Volu

    m

    urfa

    ce A

    re

    Po Su

    0 5 10 15Contaminant Level (wt%)

    12

    Contaminant Level (wt%)

  • Apparent Changes in Pore Size Distribution from Deactivation and Regeneration www.albemarle.comfrom Deactivation and Regeneration

    Oxidic

    Spent Top

    Oxidic

    Spent TopOxidic

    Pores filled with residual oil, coke and

    t l d it i

    /g/n

    m) Spent Bottom

    Top Regenerated

    Bottom Regenerated

    /g/n

    m) Spent Bottom

    /g/n

    m) metal deposits in

    spent catalystSintering and change

    V/dD

    (ml/

    V/dD

    (ml/

    V/dD

    (ml/ Sintering and change

    of pore size may occur during

    dVdVdV regeneration

    13

    Pore Diameter (nm)Pore Diameter (nm)Pore Diameter (nm)

  • Apparent Changes in Pore Size Distribution from Deactivation and Regeneration www.albemarle.comfrom Deactivation and Regeneration

    Pores filled with residual oil, coke and

    t l d it i

    Oxidic

    Spent

    metal deposits in spent catalystSintering and changeg

    /nm

    )

    Spent ResulfidedRegenerated

    Sintering and change of pore size may occur on regeneration/d

    D (m

    l/g

    H2S/H2 resulfiding removes residual oil and soft coke

    dV/

    and soft coke

    14

    Pore Diameter (nm)

  • Typical Contaminants Distribution in a VGO Demet Catalyst: SEM EDX www.albemarle.comVGO Demet Catalyst: SEM-EDX

    L ti it tLow activity outer partSi near surfaceSi near surfaceNi, V, Fe deposition throughout thethroughout the particle

    15

  • Typical Contaminants Distribution in a Main Bed Catalyst: SEM EDX www.albemarle.comMain Bed Catalyst: SEM-EDX

    Hi h ti it tHigh activity outer partAll contaminantsAll contaminants near surface

    16

  • Fe Deposits on Main Bed Catalyst Extrudate Surface www.albemarle.comExtrudate Surface

    Fe originates mainly from corrosion products (Fe oxide and sulfide) in the field and during transportation / storage

    17

    Some crudes contain trace amounts of organic Fe compounds

  • SEM-EDX near Extrudate Surface: Si Deposits Form New Outer Layer on Main Bed Catalyst www.albemarle.comForm New Outer Layer on Main Bed Catalyst

    Al d fi th i i lAl defines the original pellet boundarySi originates from

    17mSi originates from anti-foam agents used by the refineryused by the refineryFe also in the Si layerV on catalyst surfaceV on catalyst surface

    18

  • STEM-EDX Using Extrudate Sections: Main Bed Catalyst Contaminated with As www.albemarle.comMain Bed Catalyst Contaminated with As

    Method enables analysis of et od e a

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