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An approach to cost reduction in multi-stage bio-oil ... · PDF fileAn approach to cost reduction in multi-stage bio-oil hydroprocessing: applying molybdenum carbide catalysts Jae-Soon

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  • An approach to cost reduction in

    multi-stage bio-oil hydroprocessing:

    applying molybdenum carbide

    catalysts

    Jae-Soon Choi, Beth Armstrong, Raynella Connatser, Ilgaz Soykal,

    Harry Meyer, Viviane Schwartz

    Oak Ridge National Laboratory

    Alan Zacher, Huamin Wang, Mariefel Olarte, Susanne Jones

    Pacific Northwest National Laboratory

  • Project goal is catalyst development to help reduce

    fast pyrolysis bio-oil hydroprocessing costZacher, et al., Green

    Chemistry 16 (2014) 491-515.

    Bio-oil hydroprocesing: multi-step processes

    1st step: stabilization (mild hydrogenation)

    Low temperature (150-250 C)

    Ru/C type catalysts

    Can be multi-step

    2nd step: deep hydrogenation and hydrocracking

    High temperature (350-400 C)

    Sulfided Ni(Co)Mo/Al2O3 type catalysts

    carbon

    Ru Ru Ru Ru

    expensive

    weak metal-support interaction (leaching)

    under reducing conditions

    Al2O3

    sulfides

    hydrothermally unstable

    (high water content in bio-oil)

    unstable

    (low S content in

    bio-oil)

    coking ubiquitous, but

    regeneration proven difficult

    Limited long-term

    operability is a key

    cost driver

  • We are designing catalysts tailored to bio-oil based on

    transition-metal carbides

    Transition metal carbides exhibit precious-metal-like catalytic properties (Mo2C - Ru, WC - Pt)

    Carbides are active under petroleum hydrotreating conditions

    No need for sulfiding agents (cf. CoMo/Al2O3)

    Carbides can be prepared with high surface area

    No need for supports to disperse active phases (cf. Ru/C, CoMo/Al2O3) => mitigate issues associated with supports

    Performance unproven in real bio-oil upgrading involving hot water & oxygenate-rich environments

    Catalytic reactivity

    Stability (hydrothermal, oxidation, coking) & regenerability

    interstitial C

    Mo2C, WC

    Theory: C insertion to parent

    metal lattices makes metal

    electronic structures closer to

    those of precious metals

  • 2-stage hydrotreater

    Techno-economic analysis

    Assess cost reduction potential Carbides vs. Baseline Catalyst cost, regeneration interval,

    H2 consumption, oil yield

    Input for project decision making Research priority Go/No-Go decision

    Research approach

    Catalyst design & synthesis

    Shaped bulk

    carbides

    Reactor evaluation

    with real bio-oils

    Activity Selectivity Stability Regenerability

    Characterization

    Understand correlations between synthesis conditions, structures &

    performance

    Leverage DOE SC capabilities

    Model compound studyMicro-scale analysis

    scale up

    Iterative

    process

  • Developed doped carbide bead synthesis method

    Synthesis variables Dopant type & loading

    MoO3 loading

    Binder type & loading

    Characterization & model compound study guided sample selection for real bio-oil study

    1st series (BC01-04): assess the impact of dopant type

    2nd series (BC05-07): assess the impact of dopant loading

    3rd series (BC09): study regenerability

    catalyst code

    Bulk Mo carbides selected for detailed evaluation

    20 30 40 50 60 70 80 90

    Co

    un

    ts

    Position [ 2Theta]

    Doped Mo2C

    beads

    MoO3 powder Doped MoO3beads

  • Performance of Mo carbides evaluated with real bio-oil

    2-stage reactor (40 ml) Feed: raw bio-oil obtained from pine wood via conventional fast pyrolysis

    vs.

    Baseline

    sulfided

    Ru/C

    +

    sulfided

    NiMo/Al2O3

    Mo2C

  • Catalyst code Baseline BC01-09

    Stage 1 catalyst Sulfided Ru/C Doped Mo2C

    Stage 2 catalyst Sulfided NiMo/Al2O3 Doped Mo2C

    Stage 1 temperature, C 190 180

    Stage 2 temperature, C 400 400

    Pressure, psia 1800 1750-1820

    H2/bio-oil, mL/mL 1935 1676-1715

    Stage 1 LHSV, h-1 0.17 0.25

    Stage 1 WHSV, h-1 0.44 0.29

    Stage 2 LHSV, h-1 0.17 0.25

    Stage 2 WHSV, h-1 0.31 0.29

    2-stage hydroprocessing reactor parameters

    LHSV: Mo2C > Ru/C ~ Mo sulfide => lower capex WHSV: Mo2C ~ Mo sulfide < Ru/C => higher opex

    But operating conditions & catalysts not optimized for Mo carbides See later that BC09 can perform well at higher WHSV

  • 0.6

    0.7

    0.8

    0.9

    1

    0 20 40 60

    Den

    sit

    y

    Time on stream (h)

    BC01

    BC02

    BC03

    BC09

    Baseline

    Mo carbides can achieve performance similar to Baseline

    Overall comparable hydroprocessing results

    Product yields

    Oil density (degree of deoxygenation: activity)

    Oil composition (fuel product distribution)

    Activity dependent on formulation (e.g., oil density of BC09 vs. BC03)

    0

    10

    20

    30

    40

    50

    BC0115h

    BC0215h

    BC0321h

    Baseline49h

    Perc

    en

    tag

    e

    Oil sample name

    Naphtha

    Distillate

    Fuel oil

    Oil density 0.84 0.83 0.87 0.84

    Product yields

    0

    0.1

    0.2

    0.3

    0.4

    0.5

    0.6

    0.7

    0 20 40 60

    Yie

    ld

    Time on stream (h)

    aqueous

    oil

    gas

    Oil composition

    (SimDist)

    Oil density

  • Bio-oil can be sufficiently upgraded over Mo carbides

    Net improvements in H/C ratio, residual O & H2O content, TAN, and density

    TOS (h) C

    (wt %, dry)

    H

    (wt %, dry)

    H/C ratio

    (dry)

    O

    (wt %, dry)

    H2O

    (wt %)

    N

    (wt %,

    wet)

    S

    (wt %,

    wet)

    TAN

    (mg

    KOH/g)

    Density

    (g/mL)

    Feed bio-oil

    N/A 53.3 6.8 1.53 39.9 30.0

  • Stability of Mo carbides sensitive to formulations

    0.7

    0.8

    0.9

    1

    0 20 40 60

    Den

    sit

    y

    Time on stream (h)

    BC01

    BC02

    BC03

    BC04

    BC05

    BC07

    BC09

    Baseline

    BC06 fouled before reaching steady state

    (i.e., within 12 h TOS)

    Extensive catalyst bed

    fouling/plugging

    2 modes of deactivation: gradual activity loss vs. bed plugging

    Stability highly dependent on dopant type & loading: some formulations (BC04, 06, 07) suffered bed plugging before completion of a 60-h run

    Elucidating structure-stability relationship needed

  • 0

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    0 20 40 60 80 100 120 140

    Co

    nce

    ntr

    ati

    on

    (a

    t.%

    )

    Depth (nm)

    Mo oxide

    BC05 fresh

    BC05 tested stage 1

    BC05 tested stage 2

    XPS Mooxide

    0

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    0 20 40 60 80 100 120 140

    Co

    nce

    ntr

    ati

    on

    (a

    t.%

    )

    Depth (nm)

    Mo oxide

    BC06 fresh

    BC06 tested stage 1

    BC06 tested stage 2

    XPS Mooxide

    Mo carbide structure robust in bio-oil hydroprocessing

    & deactivation mainly due to coking

    No significant oxidation Carbon accumulation on the surface was a major change

    20 30 40 50 60 70 80

    Inte

    nsit

    y (

    a.u

    .)

    2 ( )

    BC05 fresh

    BC05 tested stage 1

    BC05 tested stage 2

    XRD

    20 30 40 50 60 70 80

    Inte

    nsit

    y (

    a.u

    .)

    2 ( )

    BC06 fresh

    BC06 tested stage 1

    BC06 tested stage 2

    XRD

    0

    10

    20

    30

    40

    50

    60

    70

    80

    0 20 40 60 80 100 120 140

    Co

    nce

    ntr

    ati

    on

    (a

    t.%

    )

    Depth (nm)

    C surface

    BC05 fresh

    BC05 tested stage 1

    BC05 tested stage 2

    XPS Ccont.

    0

    10

    20

    30

    40

    50

    60

    70

    80

    0 20 40 60 80 100 120 140C

    on

    ce

    ntr

    ati

    on

    (a

    t.%

    )Depth (nm)

    C surface

    BC06 fresh

    BC06 tested stage 1

    BC06 tested stage 2

    XPS Ccont.

    BC05 run 60 h w/o plugging

    BC06 run 12 h w/ stage 2 entrance plugging

  • Deposited carbon species quite reactive toward H2

    Most of C deposited during hydroprocessing removable well below 700 C (carbide synthesis temperature)

    Non-destructive (w/o sintering & carbidic C removal) in situregeneration seems feasible

    Lower temperature likely enough under higher H2 pressures

    Temperature programmed reduction in H2 at atmospheric pressure

    0.0E+00

    5.0E-12

    1.0E-11

    1.5E-11

    2.0E-11

    2.5E-11

    3.0E-11

    100 200 300 400 500 600 700 800

    m/z

    15

    sig

    na

    l (a

    .u.)

    Temperature ( C)

    BC05 fresh

    BC05 stage 1

    BC05 stage 2

    0.0E+00

    5.0E-12

    1.0E-11

    1.5E-11

    2.0E-11

    2.5E-11

    3.0E-11

    100 200 300 400 500 600 700 800

    m/z

    15

    sig

    na

    l (a

    .u.)

    Temperature ( C)

    BC06 fresh

    BC06 stage 1

    BC06 stage 2

  • Mo carbides are in situ regenerable

    Reduction in H2 recovers catalytic performance

    Consistent w/ characterization results: coking is the major deactivation route, but C species are reactive

    Bulk structure of Mo2C robust over 240-h operation + regen.

    20 30 40 50 60 70 80

    Inte

    nsit

    y (

    a.u

    .)

    2 ( )