CFD MODELING OF TRICKLE BED REACTORS: Hydro-processing...
Transcript of CFD MODELING OF TRICKLE BED REACTORS: Hydro-processing...
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CFD MODELING OF TRICKLE BED REACTORS: Hydro-processing Reactor
Prashant R. Gunjal, Amit Arora and Vivek V. Ranade
Industrial Flow Modeling GroupNational Chemical Laboratory
Pune 411008Email: [email protected]
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CFD Modeling of Trickle Bed Reactors
OUTLINE
• Trickle Bed Reactors– Applications/ flow regimes– Experiments
• CFD Modeling of Trickle Bed Reactors– Inter-phase momentum exchange/ capillary terms– Estimation of fraction of liquid suspended in gas phase
• Simulating Hydro-processing Reactor– Reaction kinetics/ other sub-models– Influence of reactor scale
• Concluding Remarks
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CFD Modeling of Trickle Bed Reactors
TRICKLE BED REACTORS
• Wide Applications– Hydro-de-sulfurization– Hydro-cracking/ hydro-treating– Hydrogenation/ oxidation– Waste water treatment
• Key Characteristics– Close to plug flow/ Low liquid hold-up– Suitable for slow reactions
– Poor heat transfer/ possibility of mal-distribution– Difficult scale-up
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CFD Modeling of Trickle Bed Reactors
TRICKLE BED REACTORS
Gas & Liquid Flow through Void Spaceε = 26-48 %
GasLiquid
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CFD Modeling of Trickle Bed Reactors
FLUID DYNAMICS OF TBR
Characterization of Packed Bed
Wetting of Solid Surface by
Liquid
Flow Regimes & Global Flow
Characteristics
Mal-distribution, Channeling &
Mixing
ε, ∆P, αL, η, RTD
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CFD Modeling of Trickle Bed Reactors
FLOW REGIMES
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CFD Modeling of Trickle Bed Reactors
EXPERIMENTS AT NCL
• Hydrodynamics– Pressure Drop– Liquid Hold-up
• Conductivity Probes– Residence Time Distribution
• Liquid Distribution at Inlet– Uniform– Non-uniform
• Experimental Parameters– Bed Diameter: 0.1 & 0.2 m– Particle Diameter: 3 & 6 mm– Liquid Velocity: < 24 mm/ s – Gas Velocity: < 0.50 m/ s– Tracer : NaCl
Data Acquisition
From Compressor Liquid Tank
Column with 3mm or 6mm Glass Beads
SeparatorConductivity
Probe
101
Pressure Indicator
Pump
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CFD Modeling of Trickle Bed Reactors
TYPICAL PRESSURE DROP DATA
0
5
10
15
20
25
30
35
0 10 20 30Liquid Flow Rate, Kg/m2s
Pres
sure
gra
dien
t, K
Pa/m
Trickle f low regime
Pulse f low regime
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CFD Modeling of Trickle Bed Reactors
PUBLISHED EXPERIMENTAL DATA
00.20.40.60.8
1
1.21.41.61.8
2
0 5 10 15 20 25
Liquid Velocity VL, (Kg/m2s)
Supe
rfic
ial G
as V
eloc
ity V
g, (m
/s)
φL= ?
Trickle Flow1
3
1. Szady and Sundersan (1991)2. Rao et. al (1983) 3. Specchia and Baldi (1977)
Pulse Flow
Spray Flow
Bubbly Flow
φL=βL
φL=?
φL βL
2
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CFD Modeling of Trickle Bed Reactors
MODELING OF MACROSCOPIC FLOW
• Bed Porosity: Scale of Scrutiny
– Bed diameter/ length: overall ε– Intermediate scale: Gaussian distribution– Smaller than particle diameter: Bi-modal distribution
• Approach Used:
– Experimentally measured or estimated radial variation of axially averaged bed porosity
– Specify porosity by drawing a sample assuming Gaussian distribution with specified variance
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CFD Modeling of Trickle Bed Reactors
CHARACTERIZATION OF PACKED BED
• Radial Variation of Porosity: Mueller (1991)
( )
( )
( )
Function Besselorder zero is J and r/Dr
D/d0.724-0.304b
D/d13.0for 9.864D/d
2.932-7.383a
13.0D/d2.61for 3.156D/d
12.98-8.243a
)e(ar)Jε(1εrε
tho
*P
PP
PP
br*oBB
=
=
≤−
=
≤≤−
=
−+= −
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CFD Modeling of Trickle Bed Reactors
CHARACTERIZATION OF PACKED BED
• Mueller’s CorrelationThree data sets from literature Our experiments
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 0.2 0.4 0.6 0.8 1Dimensionless Radius
Por
osity
D=0.194m, dp=3mm
D=0.194m, dp=6mm
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 0.2 0.4 0.6 0.8 1
Dimensionless Radius
Poro
sity
Szady and Sundersan (1991)
Rao et.al. (1983)
Spacchia and Baldi (1977)
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CFD Modeling of Trickle Bed Reactors
VARIATION OF BED POROSITY
– Selection of appropriate value is not straight forward: RTD may help
r/R
0.70
0.56 With std dev=0
With std dev=5%
With std dev=10%
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CFD Modeling of Trickle Bed Reactors
CFD MODEL
• Multi-fluid Model (Eulerian-Eulerian)Continuity Equation
0=⋅∇+∂
∂KKK
KK Ut
ρερε
Momentum Balance Equation
( ) ( )RkRKKKK
KKKKKKKK
UUFgU
PUUtU
−++∇⋅∇
+∇−=⋅∇+∂
∂
,
)()(
ρεµε
ερερε
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CFD Modeling of Trickle Bed Reactors
CFD MODEL
• Inter-phase Coupling Terms (Attou & Ferschneider, 2000)
( )⎟⎟
⎠
⎞
⎜⎜
⎝
⎛⎥⎦
⎤⎢⎣
⎡−
−−+⎥
⎦
⎤⎢⎣
⎡−
−=
333.0
2
667.0
22
21
)1()1(
)1()1(
G
L
pG
GLGP
G
L
pG
GGGL d
UUEd
EFε
εε
ερε
εε
εµε
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛⎥⎦
⎤⎢⎣
⎡−
−+⎥
⎦
⎤⎢⎣
⎡−
−=
333.0
2
667.0
22
21
)1()1(
)1()1(
G
S
pG
GGP
G
S
pG
GGGS d
UEd
EFε
εε
ερε
εε
εµε
⎟⎟⎠
⎞⎜⎜⎝
⎛+=
pL
SGP
pL
sLLS d
UEd
EFε
ερεµεε 2
22
21
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CFD Modeling of Trickle Bed Reactors
CFD MODEL
• Capillary Terms
• Attou and Ferschneider (2000)
⎟⎟⎠
⎞⎜⎜⎝
⎛−=−
21
112dd
PP LG σ
⎟⎟⎠
⎞⎜⎜⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛−−
=−L
G
PGLG F
dPP
ρρ
εεσ 5416.0
112
333.0
( ) ⎟⎟⎠
⎞⎜⎜⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛
∂∂
⎟⎟⎠
⎞⎜⎜⎝
⎛
−+
∂∂
⎟⎟⎠
⎞⎜⎜⎝
⎛−⎟⎟
⎠
⎞⎜⎜⎝
⎛−
=∂∂
−∂∂
−
L
GG
G
ss
G
/
G
s
p
LG
ρρ
Fzε
εε
zε
εεε
d.σ
zP
zP
2
32
111
14165
32
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CFD Modeling of Trickle Bed Reactors
CFD MODEL
• Capillary Terms
– Extent of Wetting, f (Jiang et al., 2002)
• Scalar Transport
iimiKKiKKKiKK SCDCU
tC
+∇⋅−∇=⋅∇+∂
∂ )( .ρερερε
cLG PfPP )1( −=−
025.01.881 <+=⎟⎟⎠
⎞⎜⎜⎝
⎛
L
G
L
G
L
G forFρρ
ρρ
ρρ
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CFD Modeling of Trickle Bed Reactors
SIMULATED RESULTS
0
5
10
15
20
25
30
35
40
45
0 0.02 0.04 0.06 0.08 0.1
Velo city M agnitude, m/ sec
Non-prewetted Bed
Prewetted Bed
0
5
10
15
20
25
30
35
0 0.1 0.2 0.3Liquid Holdup
Non-prewetted BedPrewetted Bed
Pre-wetted Un-wetted
VL= 6 mm/ s, VG=0.22 m/ s, D=0.114 m, dP= 3 mm, σ=5%
Con
tour
s of
Liq
uid
Hol
d-up
Distributions within the bed
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CFD Modeling of Trickle Bed Reactors
SIMULATED RESULTS
Column Diameter = 0.114 m Particle Diameter = 3 mm, VG=0.22 m/ s
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CFD Modeling of Trickle Bed Reactors
SIMULATED RESULTS
VG= 0.22 m /s, D = 0.114 m VG= 0.22 m /s, D = 0.194 m
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CFD Modeling of Trickle Bed Reactors
GAS-LIQUID FLOW IN TBR
• Estimation of Frictional Pressure Drop & Fraction of Liquid Supported by Gas
– Simulate at two values of ‘g’ (9.7, 9.9 m/s2)
21
12
21
ggLPg
LPg
LPf
−
⎟⎠⎞
⎜⎝⎛ ∆−⎟
⎠⎞
⎜⎝⎛ ∆
=⎟⎟⎠
⎞⎜⎜⎝
⎛ ∆
( )21L
12L gg
LP
LP
−ρ
⎟⎠⎞
⎜⎝⎛ ∆−⎟
⎠⎞
⎜⎝⎛ ∆
=φ
Fraction of Liquid Hold-up Supported by Gas Phase < 1
Solid
Liquid
Gas
( )
LL
Lf ρ
βφ
φ
≤
−⎟⎟⎠
⎞⎜⎜⎝
⎛ ∆=⎟
⎠⎞
⎜⎝⎛ ∆
Q
gLP
LP
LGLGL
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CFD Modeling of Trickle Bed Reactors
SIMULATED RESULTS
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.00 0.20 0.40 0.60 0.80 1.00Liquid Flow Rate x10-1, kg/m2s
Liqu
id S
atur
atio
n a
ndL
Holub et. al. (1993) -Experimental dataSzady and Sundersan (1991)-Exp. DataCFD ResultsSupported Liquid Saturation
Calibrate Model Parameters from ∆P
Can Predict Total and Supported Liquid Volume Fraction
0
2
4
6
8
10
12
14
0.00 0.20 0.40 0.60 0.80 1.00Liquid Flow Rate x10-1, Kg/m2s
Pres
sure
Gra
dien
t KPa
/m
Saez and Corbonell (1985)-Exp. dataSzady and Sundersan (1991)-Increase in liquidSzady and Sundersan (1991)-decrease in liquidCFD Simulations w ithout Capillary ForceCFD Simulations
Operating conditions:VG=0.22m/s, D/dp =55, dp=3mm, Std. Dev.=5%, E1=215, E2=1.75
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CFD Modeling of Trickle Bed Reactors
SIMULATED RESULTS
0
10
20
30
40
50
0 0.2 0.4 0.6 0.8 1Gas Flow Rate, (Kg/m2s)
Pres
sure
Dro
p, (K
Pa/m
) CFD ResultsExperimental Data
0
0.1
0.2
0.3
0.4
0.5
0 0.2 0.4 0.6 0.8 1Gas Mass Velocity, kg/m2s
Liqu
id S
atur
atio
n an
d L
Liquid Saturation- CFD ResultsSupported Liquid SaturationLiquid Saturation- Exp. Data
Data of Spachio & Baldi (1977)
As gas velocity increases, more & more liquid is
supported by gas
Operating conditions: VL=2.8x10-3 m/s, dp=3mm, D/dp=30, Std. Dev.=5%, E1=500, E2=3
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CFD Modeling of Trickle Bed Reactors
SIMULATED RESULTS
0
0.04
0.08
0.12
0.16
0.2
0 2 4 6 8Gas mass velocity, Kg/m2s
Liqu
id S
atur
atio
n an
dL
Liquid Saturation- CFD ResultsSupported Liquid SaturationLiquid Saturation Exp. Data
0
40
80
120
160
200
0 2 4 6 8Gas Mass Velocity, (kg/m2s)
Pres
sure
Dro
p, (K
Pa/m
) Experimental DataCFD Results Data of Rao et al. (1983)
As gas velocity increases, more & more liquid is
supported by gas
Operating conditions:VL=1x10-3m/s, D/dp =15.4, dp=3mm, Std. Dev.=5%, E1=215, E2=3.4
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CFD Modeling of Trickle Bed Reactors
RESIDENCE TIME DISTRIBUTION
0
0.02
0.04
0.06
0.08
0.1
0.12
0 20 40 60 80 100 120Time, (sec)
E(t),
sec
-1
Pre-wetted Bed
Non Pre-wetted Bed
Simulation Results
1
1
1
Experimental Results2
2
2
Operating conditions: VL=2.06x10-3m/s VG=0.22m/s, D/dp =18, dp=6mm, Std. Dev.=5%, E1=180, E2=1.75
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CFD Modeling of Trickle Bed Reactors
MODELING OF HYDRO-PROCESSING REACTOR
• Reaction and Kinetics (Chowdhury et al. 2002)Hydro-desulfurisation (HDS)
SH,LAd
6.1S,L
56.0H,L
HDS2
2
cK1cck
r+
−=SHArH2SAr 22 +→+−
De-aromatisation of Mono-, Di- and Poly- Aromatics
NaphMono_MonoMonoMono CkCkr +−=NapthenesH3ArMono 2 ⇔+−
MonoDi_DiDiDi CkCkr +−=ArMonoH2ArDi 2 −⇔+−
DiPoly_PolyPolyPoly CkCkr +−=ArDiHArTri 2 −⇔+−
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CFD Modeling of Trickle Bed Reactors
SIMPLIFICATIONS/ ASSUMPTIONS
• Pressure drop is insignificant compared to the operating
pressure
• Trickle bed reactor is operated isothermally (efficient heat
transfer)
• Ideal gas law is applicable
• Liquid phase reactants are non-volatile (negligible vapor
pressure)
• Gas-liquid mass transfer is the limiting resistance.
• The catalyst particles are completely wetted
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CFD Modeling of Trickle Bed Reactors
MODEL EQUATIONS
• Mass Balance of Species i
• Source Terms for Gas Phase
• Source Terms for Liquid Phase
( ) ( ) kikkikmikkikkkkikkk SCDCU
tC
,,,.,, ρερερε
ρε+∇−=⋅∇+
∂∂
⎥⎦
⎤⎢⎣
⎡−−= Li
i
GiGLGLii C
HC
aKS
∑=
=
+⎥⎦
⎤⎢⎣
⎡−=
nrj
1jijB rηρLi
i
GiGLGLii C
HC
aKS
∑=
=
=nrj
1jijB rηρiS
![Page 29: CFD MODELING OF TRICKLE BED REACTORS: Hydro-processing Reactorweb.wpi.edu/academics/che/HMTL/CFD_in_CRE_IV/Ranade.pdf · CFD MODELING OF TRICKLE BED REACTORS: Hydro-processing Reactor](https://reader030.fdocuments.in/reader030/viewer/2022021419/5abb485f7f8b9a567c8c7076/html5/thumbnails/29.jpg)
CFD Modeling of Trickle Bed Reactors
MODEL EQUATIONS
• Mass Transfer Coefficient (From Goto & Smith, 1975)
• Solubility of Hydrogen/ H2S (Korsten et al. 1996)
2/1
1
2
⎟⎟⎠
⎞⎜⎜⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛= L
iL
L
L
LLi
LLi
DG
Dak
ρµ
µα
α
Li
NiH ρλ
υ.
=
220
42
320
210H1.aTaTaTaa
2 ρ++
ρ++=λ
).008470.03670.3exp(2
TSH −=λ835783.0a
1094593.1a
1007539.3a
1042947.0a
559729.0a
4
63
32
31
0
=×=
×=
×−=
−=
−
−
−
: molar gas volumeNυ
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CFD Modeling of Trickle Bed Reactors
CASE STUDIES
• Gas and Liquid Superficial Velocities Increase with Scale
• Wetting gets Better with Scale
Parameters Laboratory Scale Reactor(Chowdhury et al. 2002)
Commercial Scale Reactor(Bhaskar et al. 2004)
Reactor Diameter, mBed Length
Particle Diameter, mBed Porosity
LHSV, h-1Operating Pressure, MpaOperating Temperature, K
Initial H2S Conc., v/v %
0.0190.5 m0.00240.50
1-520-28
573-693 0.5-8
3.816 m
0.00150.36
1-520-80
573-693 0.5-8
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CFD Modeling of Trickle Bed Reactors
KINETICS/ OIL COMPOSITION
• From Chowdhury et al. (2002)
AdK
Kinetic Constants Values
, m3/kmol 50000
K, Dimensionless 2.5 X 1012 exp(-19384/T)
k*mono, m3/kg.s 6.04 X 102 exp(-12414/T)
k*Di, m3/kg.s 8.5 X 102 exp(-12140/T)
k*poly, m3/kg.s 2.66 X 105 exp(-15170/T)
Component Percentage
Ar-S % 1.67
Poly-Ar % 2.59
Di-Ar % 8.77
Mono-Ar % 17.96
Naphthenes % 19.25
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CFD Modeling of Trickle Bed Reactors
SIMULATED RESULTS-1
Temperature Initial Concentration of H2S
0
25
50
75
100
573 583 593 603 613 623 633 643 653
Temp, K
Con
vers
ion,
Ar-
S %
Varying Porosity
Uniform Porosity
Ar-S Exp
0
30
60
90
0 2 4 6 8
Initial H2S Conc Gas Phase ( %, V/V)
Conv
ersi
on, x
(P=4 MPa, LHSV=2.0 h-1, QGNTP/QL=200 m3/m3, TR=320oC, yH2S=1.4% )Symbols denote experimental data of Chowdhury et al. (2002)
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CFD Modeling of Trickle Bed Reactors
SIMULATED RESULTS-2
(P=4 MPa, LHSV=2.0 h-1, QGNTP/QL=200 m3/m3, yH2S=1.4%)Symbols denote experimental data of Chowdhury et al. (2002)
0
10
20
30
40
50
60
70
80
90
573 593 613 633 653Temperature, K
Con
vers
ion,
%
Ar-Ptotaltotalpoly
0
10
20
30
40
50
60
573 593 613 633 653Temperature, K
Con
vers
ion,
%
Ar-D
Ar-M
Ar-Di-Expt
Ar-Mono-Exp
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CFD Modeling of Trickle Bed Reactors
SIMULATED RESULTS-3
0
10
20
30
40
50
60
2 2.4 2.8 3.2 3.6 4
LHSV, h-1
Con
vers
ion,
%
Total-ArAr-Poly
Ar-DiAr-Mono
(P=4 MPa, TR=320 oC, QGNTP/QL=200 m3/m3, yH2S=1.4%, filled symbols are for experimental data of Chowdhury et al., 2002)
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CFD Modeling of Trickle Bed Reactors
INFLUENCE OF REACTOR SCALE
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0 0.2 0.4 0.6 0.8 1
Dimensionless Radius
Dim
ensi
onle
ss S
olid
Hol
d-up
0
5
10
15
20
25
30
35
Dim
ensi
onle
ss L
ocal
Axi
al V
eloc
ity
Solid hold-upLocal Axial Velocity
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0 0.2 0.4 0.6 0.8 1
Dimensionless RadiusD
imen
sion
less
Sol
id H
old-
up
0
1
2
3
4
5
6
7
Dim
ensi
onle
ss L
ocal
Axi
al V
eloc
ity
Solid hold-upLocal Axial Velocity
Industrial (LHSV=2)Laboratory (LHSV=3)
(P=4 MPa, TR=320 oC, QGNTP/QL=300 m3/m3)
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CFD Modeling of Trickle Bed Reactors
INFLUENCE OF REACTOR SCALE
25
50
75
100
573 593 613 633 653
Temperature, K
Con
vers
ion,
% Lab-scale ReactorCommercial Reactor
0
2000
4000
6000
8000
10000
12000
573 593 613 633 653Temperature, K
Out
let C
onc.
Ar-
S, p
pm
Lab Scale Reactor
Commercial Reactor
(Plab & com=4 & 4.4 MPa, LHSVlab=2.0 h-1, QGNTP/QL=200 m3/m3, yH2S=1.4%)
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CFD Modeling of Trickle Bed Reactors
INFLUENCE OF REACTOR SCALE
-20
0
20
40
60
80
100
573 593 613 633 653Temperature, K
Con
vers
ion,
%
Poly-ArTotalPoly-Ar-CommercialTotal-Commercial
505560
6570758085
9095
100
2 2.5 3 3.5 4LHSV, h-1
Con
vers
ion,
%
Ar-S-Lab Scale
Ar-S-Commercial
(Plab & com=4 & 4.4 MPa, LHSVlab & com=2.0 & 3.0 h-1, (QGNTP/QL)lab & com= 200 & 300 m3/m3, yH2S=1.4%)
(Plab & com=4 & 4.4 MPa, Temperature= 593 K,(QGNTP/QL)lab & com= 200 & 300 m3/m3, yH2S=1.4%)
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CFD Modeling of Trickle Bed Reactors
INFLUENCE OF REACTOR SCALE
0
20
40
60
80
100
120
2 3 4 5 6 7 8
Pressure, MPa
Con
vers
ion,
%
Poly-Ar
Di-Ar
Mono-Ar
Total
0
10
20
30
40
50
60
70
80
90
100
2 2.5 3 3.5 4LHSV, h-1
Con
vers
ion,
%
Poly-ArDi-ArMono-ArTotal
(QGNTP/QL)lab & com= 200 & 300 m3/m3 T=593 KLHSVlab & com=2.0 & 3.0 h-1 ,yH2S=1.4%
Plab & com=4 & 4.4 Mpa, T=593 K yH2S=1.4%(QGNTP/QL)lab & com= 200 & 300 m3/m3
Continuous lines: commercial; Dotted lines: laboratory scale
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CFD Modeling of Trickle Bed Reactors
CONCLUDING REMARKS
• Macroscopic CFD Model Reasonably Simulates Gas-liquid Flow in Trickle Beds– Liquid hold-up– Residence time distribution– May be used to estimate fraction of suspended liquid
• Further Work is Needed for Understanding Wetting/ Hysteresis to Make Further Progress
• Despite Limitations, CFD Models can be Used to Understand Key Issues in Reactor Engineering Including Scale-up & Scale-down
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CFD Modeling of Trickle Bed Reactors
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CFD Modeling of Trickle Bed Reactors
MODELING OF MESO-SCALE FLOWS
• Single Phase Flow through Packed Bed– Unit cell approach– Simple cubic, FCC, rhombohedral ..– Inertial flow structures, pressure drop, heat transfer
• Interaction of Liquid Drop/ Film with Solid Surface– Regimes of interaction– Dynamic contact angle/ surface characteristics– VOF simulations– Insight into capillary forces???
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CFD Modeling of Trickle Bed Reactors
SINGLE PHASE FLOW
• Single Phase Flow through Packed BedPeriodic Flow
Wall
Wall
Periodic Flow
Wall
Operating Parameters• Cell Length 28mm, 3mm• Fluid Water• Particle Reynolds Number 12-6000
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CFD Modeling of Trickle Bed Reactors
SINGLE PHASE FLOW
Experiments:Suekane et al. AIChE J., 49, 1
Simulations
0
5
0
4.5
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CFD Modeling of Trickle Bed Reactors
SINGLE PHASE FLOW
0
1
2
3
-1 -0.5 0 0.5 1x/r
Vz/V
mea
n
Experimental
Simulat ion-28mm
Simulat ion-3mm
-1
0
1
2
3
4
-1 -0.5 0 0.5 1x/r
Vz/V
mea
n
Experimental
Simulat ion-28mm
Simulat ion-3mm
-1
0
1
2
3
4
5
-1 -0.5 0 0.5 1x/r
Vz/V
mea
n
Experimental
Simulat ion-28mm
Simulat ion-3mm
-1
0
1
2
3
4
5
-1 -0.5 0 0.5 1x/r
Vz/V
mea
n
Experimental
Simulat ion-28mm
Simulat ion-3mm
![Page 45: CFD MODELING OF TRICKLE BED REACTORS: Hydro-processing Reactorweb.wpi.edu/academics/che/HMTL/CFD_in_CRE_IV/Ranade.pdf · CFD MODELING OF TRICKLE BED REACTORS: Hydro-processing Reactor](https://reader030.fdocuments.in/reader030/viewer/2022021419/5abb485f7f8b9a567c8c7076/html5/thumbnails/45.jpg)
CFD Modeling of Trickle Bed Reactors
SINGLE PHASE FLOW
E
S
Vz=8.66mm/s
Max arrow length :A=0.26 mm/sB=0.29 mm/sC=0.44 mm/s
A: z/r=0.14 (experimental) B: z/r=0.28 (experimental) C: z/r=0.42 (experimental)A: z/r=0.14 (experimental) B: z/r=0.28 (experimental) C: z/r=0.42 (experimental)A: z/r=0.14 (experimental)A: z/r=0.14 (experimental) B: z/r=0.28 (experimental)B: z/r=0.28 (experimental) C: z/r=0.42 (experimental)C: z/r=0.42 (experimental)
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CFD Modeling of Trickle Bed Reactors
SINGLE PHASE FLOW
• Inertial Flow Structures were Captured Accurately by CFD Models
• Velocity Distribution in Unit Cells Resembles that in a Packed Bed
• Ergun Parameters may be Obtained through Unit Cell Approach for Semi-structured Packed Bed
• Unit Cell Approach may be Extended to Simulate Two Phase Flows to Understand Wetting
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CFD Modeling of Trickle Bed Reactors
LIQUID SPREADING ON SOLID SURFACES
Computer
CCD Camera
Monitor
Light Diffuser
Light
Drop Flow Over Pellet
Drop Rest on Flat Plate
8.79mm
1mm
φ10.4mm
![Page 48: CFD MODELING OF TRICKLE BED REACTORS: Hydro-processing Reactorweb.wpi.edu/academics/che/HMTL/CFD_in_CRE_IV/Ranade.pdf · CFD MODELING OF TRICKLE BED REACTORS: Hydro-processing Reactor](https://reader030.fdocuments.in/reader030/viewer/2022021419/5abb485f7f8b9a567c8c7076/html5/thumbnails/48.jpg)
CFD Modeling of Trickle Bed Reactors
DROP IMPACT ON SOLID SURFACE
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CFD Modeling of Trickle Bed Reactors
DROP IMPACT ON SOLID SURFACE
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CFD Modeling of Trickle Bed Reactors
FLAT SURFACE
(f)(c)
(d)
(e)(b)
(a)
t=0ms
t=16ms
t=20ms
t=36ms
t=48ms
t=240ms
t=0ms
t=10ms
t=210mst=25ms
t=45ms
t=45ms
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CFD Modeling of Trickle Bed Reactors
DYNAMICS OF DROP IMPACT
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CFD Modeling of Trickle Bed Reactors
MODELS FOR INTERPHASE COUPLING?
Wall Shear Stress on Solid Surface, red~100 Pa
Drop Shape at 12 ms
Shear Strain on Gas-liquid Interface