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    Deactivation of Hydrotreating Catalysts in Different Reaction Zones of a

    VGO FCC-Pretreatment Reactor

    S. Eijsbouts, S. Mayo, L. Burns and G. Anderson XV F d A d l I d t i d R fi ióXV Foro de Avances de la Industria de Refinación Mexico City, September 2009

  • Contents www.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 Feed Hydrotreater

    (FCC-PT)

    ( )

    Coker Gas Oils (CGO/HCGO)

    Deasphalted Oils (DAO)

    Distillate

    Light Olefins

    Other Heavy Oils

    Hydrogen

    Fluid Catalytic Cracking 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, DAOs LHSV 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 levels Very difficult feed treated at relatively low pressure/ppHVery difficult feed treated at relatively low pressure/ppH2 In 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 ur e

    Catalyst System S

    ul fu

    r

    N itr

    og en

    H 2S

    N H

    3

    pp H

    2

    em pe

    ra tu

    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 Low Zone 1 Polynuclear Aromatics High Medium – Low Zero

    H2S in Gas 0 – Medium High Highest

    NH3 in Gas 0 – Medium Medium High

    Zone 2 3 g

    H2 in Gas High Medium Medium – Low

    Main HDS Reaction Main HDS Inhibitor

    Direct H2S

    Direct + Hydrog’n Organic Nitrogen

    Hydrogenation –

    Zone 3

    a S b to 2S O ga c t oge

    Main HDN/HDA Reaction Main HDN/HDA Inhibitor

    Hydrog’n Org. N, Aroms

    Hydrogenation Org. N, Aromatics

    Hydrogenation Aromatics

    HDS Reaction Rate Fast Slow Fast

    Reaction zones vary in length and position

    HDS Reaction Rate HDN/HDA Reaction Rate

    Fast Very Slow

    Slow Slow

    Fast Slow-Medium

    7

    ULSD and Hydrocracking PT operate in all 3 zones

  • FCC-PT Catalysts www.albemarle.com

    y

    O ti i f b i Feed + 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 unit’s operating Main

    Active Catalyst

    Main Active

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

    CatalystCatalysts

    8

    objectives / constraints Products + H2

  • Sampling of Commercial Reactors www.albemarle.com

    p g

    Reactor fill between 15 800 mtReactor fill between 15-800 mt Guard bed and main bed may contain multiple catalysts Sampling 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 p catalyst layer ~ 0.005% material is sampled Chemical 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 Goal www.albemarle.com

    y

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

    Main bed catalysts: Check for presence of metal contaminantsCheck for presence of metal contaminants Determine coke content Assess 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/nm 14 wt% C → 42 at/nm2 8 wt% V2O5 → 3 at/nm2 8 wt% SiO → 5 at/nm2

    15

    20

    na nt

    L ev

    e

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

    5

    10

    C on

    ta m

    i

    Coke higher at inlet and outlet

    Higher feed C/H @ inlet

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

    11

    Higher feed C/H @ inlet Higher 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

    (m l/g

    )

    ea (m

    2 /g )Pore Volume

    Surface Area

    regenerated samples Sintering may occur during regeneration

    or e

    Vo lu

    m

    ur fa

    ce A

    re

    Po Su

    0 5 10 15 Contaminant 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 catalyst Sintering and change

    V/ dD

    (m l/

    V/ dD

    (m l/

    V/ dD

    (m l/ 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 catalyst Sintering and changeg

    /n m

    )

    Spent Resulfided Regenerated

    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 part Si near surfaceSi near surface Ni, 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 part All contaminantsAll contaminants near surface

    16

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

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