10.1 - Analysis of local transport effects in gas-liquid
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Transcript 10.1 - Analysis of local transport effects in gas-liquid
Heterogeneous Reaction Engineering:
Theory and Case Studies
Module 4
Analysis of Local Transport Effects in
Gas-Liquid-Solid Systems
P.A. Ramachandran
[email protected]
1
Outline
•
•
•
•
Transport Effects
Diagnostic plots for slurry systems
Partial wetting and implications
Slurries containing fine particles
2
Heterogeneous Liquid-Phase Reaction Phenomena
ci
catalyst
Ni
Ni
ci
T
Liquid
film
Vapor
film
Bulk liquid
Bulk vapor
E
E
Liquid
film
T
Challenges: 1. Identifying reaction(s) and their location(s)
2. Accounting for internal and external catalyst
wetting / holdup phenomena
3
Mass Transfer Resistances in
Gas-Liquid-Solid Systems
4
Local Rate of Reaction for GasLiquid-Solid Catalyzed Systems
A (g) +
b B (l)
P (l)
Gas-Liquid Mass Transfer:
RA = kLaB (A* - AL )
Liquid-Solid Mass Transfer for A:
RA = ksap (AL - As )
Liquid-Solid Mass Transfer for B:
RB = ksap (BL - Bs )
Intra particle Diffusion with Reaction:
RA = wc(As, Bs)kmnAsmBsn
5
Intraparticle Diffusion Limitations
• Solution of the reaction-diffusion equations in the catalyst
particle for some simple reactions results in effectiveness factorThiele modulus relationship similar to that represented by the
enhancement factor-Hatta number relationship for gas-liquid
reactions
tanh
k1
L
De
Other details: Froment & Bischoff (1979)
6
Observed Rate - 1st Order Reaction
in a Gas-Liquid-Solid System
• For linear kinetics and the slow reaction regime, an overall resistance can
be defined that includes the gas-liquid and liquid-solid mass transfer
and reaction terms, including intraparticle diffusion limitations
1
1
* 1
RA A
kL aB kS aPw C wk1
-1
A*
1
rb rcr
RA
w
rb ( s )
1
k LaB
rcr ( gcat s / m 3 )
1
1
k s a p c k1
7
Diagnostic Plots: First Order Case
A*/RA
A*/RA
1/w
1/w
Gas-Liquid Mass Transfer Controls
the Process
Negligible Gas-Liquid Resistance
A*/RA
Slope = rcr
Intercept = rb
1/w
Intermediate Case
8
Diagnostic Plots (contd)
A*/RA
A*/RA
Increasing resistance
to gas absorption
Decreasing Particle Size
1/w
1/w
m>1
A*/RA
m=1
m<1
m=0
1/w
Schematic Plots for other Higher Orders
9
Commonly-Used Kinetic Models
for Gas-Liquid-Solid Systems
A (g) +
b B (liq)
Mechanism
P (liq)
Rate Form
1. Single site adsorption of dissolved gas
k11 A
B
1 K A A
2. Dissociative adsorption of dissolved gas
k11 A
B
1 K A A
3. Adsorption of both A & B on single sites
k11 AB
1 K A A K B B
4. General single site adsorption for N species
k11 AB
N
1 Ki Ci
i 1
10
Overall Effectiveness Factor
for a (m,n) order Reaction
RA
0
m n
wk (A*) BL
= f(A , o)
where:
(1)
1
1
1
A*
k
a
k
a
L
s p
A
wk(A*)m BLn
R (m 1)Sp k(A*)
o
3
2De
(2)
m 1
n
L
1
2
B
(3)
11
Overall Effectiveness Factor
for a Single-Site L-H Rate Form
k11 AB
Example: Glucose Hydrogenation A
1 KA A
Ramachandran & Chaudhari, 1983
12
Analysis of External Mass Transport
Resistance
• Overall mass transfer of H2 (gas) to catalyst
surface is :
Rgas = MA(A*-As), A* - gas concentration in the liquid phase (using
Henry’s Constant)
MA (
1
1 1
)
K LaB ks a p
• Gas consumption by all reactions:
RH
2
No . of rxn
j 1
H2 , j
rj
• Considering As = 0 , we have
M A A*
No . of rxn
r
j 1
H2 , j
j
If LHS > > RHS, then no mass transfer resistance !
13
Analysis of Internal Resistance (within the
Catalyst Pellet)
• Weisz-Prater criterion
is used
r L n1
We
D C 2
2
2
obs
i
eff
b
n = reaction order, taken as unity
robs = net rate of consumption of limiting
Reactant (initial rate)
Cb = concentration of limiting reactant in liquid
Deff = effective diffusivity = DABp/τ
p= particle porosity ~ 0.5
τ = totuosity = 2
DAB = binary diffusivity (Wilke Chang correlation
L = (characteristic length) Vp/Sp
Internal Resistance is considered negligible if
We0.5 < 0.2
14
Parameter Estimation Method
•
•
•
•
Step-by-step approach
Start with a temperature data set
Identify the reactions
Identify the reaction form (reaction rate):
rj
1 K C
1
Where,
n
w cat k j C gas
Cj
K 2C 2 K 3C 3 K 4C 4 K 5C 5
2
gas
k j (or K j ) Aoj e
E
j
RT
Aoj and Ej are estimated !
15
Kinetic Parameter Estimation (contd.)
• Non-linear Optimization Problem
N
obj min(C
i 1
C i , aut oc l av
)2 , t ,runs
e
i ,pr edi c t ed
s ubj:
Aut oc lav eModel / Slurryreac t or
• Identify and select the for the objective function
• Identify the species adsorbed, if any (C1 to C5 here, as an
example)
• Develop parameter estimation program and the autoclave
model / Slurry reactor model
• Autoclave model predicts the species concentration at every
instant (for the operating conditions) – set of differential
equations can be solved by VODE routine from NETLIB
libraries
• Levenberg-Marquardt algorithm for parameter estimation –
UNLSF routine from IMSL libraries
16
Trickle-Bed Reactors
17
Fixed-Bed Multiphase Reactors
(a) Trickle - Bed
Cocurrent
downflow
(b) Trickle - Bed
Countercurrent
flow
(c) Packed - Bubble Flow
Cocurrent
upflow
Semi-Batch or Continuous Operation; Inert or Catalytic Solid Packing
18
Trickle-Bed Reactors
- Pros and Cons Pros
•
Plug-flow
•
Low liquid holdup
less
homogeneous reactions
•
•
•
high conversion
Cons
•
Intraparticle diffusion resistance
•
Incomplete contacting/wetting
•
High pressure drop
•
Temperature control problems
hot spots
•
Scale-up and design is complex
•
Attrition and crush resistant
catalyst is required
High specific reaction rate
Temperature control possible by
liquid vaporization
High pressure operation possible
•
Minimal catalyst handling issues
•
Process flexibility, reasonable
throughput limitations
•
Dirty process streams cannot be
used
plugged or fouled bed
•
Lower capital & operating costs
•
Catalyst loading is complicated
19
Fundamental Phenomena
in Trickle Bed Reactors
Macroscale
•
Axial & radial RTD’s
•
Flow regime
•
Pressure drop
•
Liquid holdup
•
Liquid flashing
•
Interphase transport
•
Liquid distribution
•
Heat transfer
•
Energy dissipation
Microscale
•
LocaL texture of liquid flow (films,
rivulets, stagnant pockets)
•
Local irrigation and wetting
•
Liquid holdup in pores
•
Local transport between gas and
flowing and stagnant liquid, and
solid
•
Local transport between flowing
liquid, stagnant liquid, and solid
•
Local transport between gas and
vapor-filled pores
20
Classification of TBR Processes
Based on Volatility
1. Nonvolatile liquid reactant
• Rate limiting reactant
- Liquid
- Gas
- Both
Reaction occurs only on wetted catalyst
2. Volatile liquid reactant
• Rate limiting reactant
- Liquid
- Gas
- Both
Reaction occurs both on wet and dry catalyst
21
Key TBR Design Parameters
•
Flow regime
•
Pressure drop
•
Liquid holdup
•
Liquid - solid contacting
•
Interphase transport coefficients
•
Intraparticle diffusion
•
Extent of liquid volatilization
•
Reaction kinetics
•
Thermo - physical constants
22
Flow Regime Structures
for Gas-Liquid Flow in Fixed-Beds
Trickle-Flow
Pulse-Flow
Spray-Flow
Bubble-Flow
Mewes, Loser, and Millies (1999)
23
Three Key Factors
Affecting Flow Regimes
1. Throughput of gas and liquid
L - liquid mass velocity
G - gas mass velocity
L / G - ratio of mass velocities
2. Physical properties of the gas and liquid
- viscosity
- surface tension
- density
3. Foaming or non-foaming characteristics of
the liquid
24
Factors Affecting Choice of L / G
• Stoichiometry of the reaction
• Pressure drop limitations
• Establishment of desired flow regime
• Foaming characteristics of liquid
• Heat removal requirement
• Maximum allowed Tad
25
Flow Regime Map for
Gas-Liquid Flow in Fixed-Beds
Gianetto, Baldi, Specchia and Sicardi, AIChEJ (1978)
26
Effect of Bed Prewetting
and Hysteresis Effects
250
non-prewetted bed
prewetted bed
Intensity of image
200
CCD Video Imagesof
Liquid Flow in 2-D Beds
Axial position: 6 cm down from top
dp = 0.3 cm
150
100
50
0
0
3
6
9 12 15 18 21 24
X (dp)
L = 3.52 Kg/m2.s
channel flow
film flow
28
Models for Trickling to Pulsing Flow
Regime Transition
• Macroscopic model - balance of inertial and capillary
forces
– Grosser, Carbonell & Sundaresan, AIChE J (1988)
– Attou & Ferschneider, CES (1999)
• Microscopic model - pore blockage by balance of
inertial and capillary forces
– Ka Ng, AIChE Jnl (1986)
• Microscopic model - wave formation on surface of
liquid film
– Holub, Dudukovic & Ramachandran, AIChE J (1993)
29
Estimation of Pressure Drop for Two-phase
Flow in Packed-Beds
Various empirical correlations based on:
• Lockhart -Martinelli parameter
• Two - phase friction factor
• Energy dissipation parameter
• Relative permeability parameter
• Other dimensionless parameters
30
Key Pressure Drop
Equation Parameters
• Single - phase pressure drop
=
P
L
150 (1 - B ) 2 u
=
B 3
d pe 3
1.75 (1 - B ) u 2
+
B 3 d pe
• Lockhart -Martinelli parameter
1/2
L
=
G
• Two - phase friction factor
1
f GL =
LG d PE uG 2 G
2
Validity:
• Low and high Interaction regimes
• Non-foaming and foaming systems
31
Pressure Drop - Summary
• Correlations based on single-phase gas and liquid P
(Ergun equation)
– Lockhart-Martinelli (1949), Larkins et al. (1961), Specchia
& Baldi (1974) - separate for low and high interaction, Kan
& Greenfield (1978) - hysteresis effect on P
• Flow models
– Relative permeability model: Saez & Carbonell, AIChE
J (1985); Levec, Saez & Carbonell, AIChE J (1985); Saez,
Levec & Carbonell, AIChE J (1985)
– Slit model: Holub, Dudukovic & Ramachandran, CES
(1992); AIChE J (1993); Al-Dahhan, Khadilkar, Wu, &
Dudukovic IEC Res. (1998); Iliuta & Larachi, CES (1999)
– Fluid- fluid interface model: Attou, Boyer & Ferschneider,
CES (1999), Attou & Ferschneider, CES (1999)
32
Liquid Holdup - Key Definitions
• Liquid holdup (HL , L ) is the fraction of reactor volume
that is occupied by liquid (m3 liquid / m3 reactor).
L = VL / VR
• Liquid saturation (L , L ) is the fraction of external
bed voidage (B ) occupied by liquid (m3 liquid / m3 voids).
L = L / B
• Fractional pore fill-up (Fi) is the fraction of catalyst pore
volume occupied by liquid (m3 liquid / m3 pore volume).
33
Key Liquid Holdup Relationships
Total Bed Voidage
t
= External Voidage + Internal Voidage
=
B
+
Total Liquid Holdup = External Holdup
L
=
LE
p ( 1 - B )
+ Internal Holdup
+
L
Internal Holdup for Liquid-Filled Catalyst Pores (Fi = 1)
LI
F i p ( 1 - B )
=
External Liquid Holdup = Dynamic Holdup + Static Holdup
LE
=
LD
+
LS
34
Typical External Holdup Values
External Liquid Holdup = Dynamic Holdup + Static Holdup
LE
LD
=
+
LS
0.1 < LE < 0.25 ( or higher at high L / G )
LS
=
NEo =
1
20 + 0. 9 NEo
L g dp 2 B2
L (1 - B )
Gravity force
Surface tension force
= Eotvos Number
35
Liquid Holdup - Summary
Contributions to the overall liquid holdup
• Internal liquid holdup (inside particle) ~ equal to particle porosity
• External liquid holdup
– dynamic (flowing liquid) - depends on flow regime and is determined
by viscous, gravity and inertial forces
– static - volume fraction of liquid retained when a pre-wetted bed is
drained, from balance of gravity and surface tension forces
HL= HLD + HLSe+ HLi = HLD + HLSe+ ip(1- B)
HL, HLD & HLe correlations for low & high interaction regime
• Separate correlations for low and high interaction regimes
• Empirical: Larachi et al. (1991), Lara-Marquez et al. (1992)
• Phenomenological: Holub et al. (1992, 1993);
Al-Dahhan & Dudukovic (1994)
36
Pressure Drop and
Liquid Holdup Correlations
MARE (%)*
L
P / L
Iliuta & Larachi (1999)
18
27
Ellman et al. (1988, 1990)
23
54
Saez et al. (1985)
22
41
Al-Dahhan & Dudukovic (‘95, ‘96) 17
32
Larachi et al. (1991)
73
22
*Mean Absolute Relative Error
Carbonell, O&G Sci & Tech, vol 55 (4) (2000)
37
Key Transport Resistances
• Gaseous reactant resistances
1 - Gas-to-liquid resistance
2 - Liquid-to-solid resistance
3 - Intraparticle diffusion and kinetic resistances
• Liquid reactant resistances
1 - Liquid-to-solid resistance
2 - Intraparticle diffusion and kinetic resistances
• Heat transfer resistances
1 - Bulk gas-to-particle
2 - Bulk liquid-to-particle
3 - Intraparticle
38
Transport Parameter Correlations
kLaB - Gas to liquid ( liquid - side )
volumetric mass transfer coefficient
kSL - Liquid to actively wetted solid mass transfer
coefficient
kSg - Gas to dry solid mass transfer coefficient
h
- Overall heat transfer coefficient
e
- Effective conductivity of particles
39
Interphase Mass Transfer Correlations Summary
Liquid side of gas-to-liquid mass transfer
• Separate correlations for low and high interaction regimes
• Wild et al. (1992); Larachi (1991); Cassanello et al. (1996)
Gas side of gas-to-liquid mass transfer
• For most situations negligible resistance
• Gotto et al. (1977); Fukushima & Kusaka (1978)
Liquid-to-solid mass transfer
• Some have separate correlations for low and high interaction
regimes
• Goto & Smith (1975), Satterfield et al. (1978), Specchia et al.
(1978)
40
Liquid - Solid Contacting in TBR’s
• Incomplete liquid - solid contacting can occur due to:
1. Reactor- scale (gross liquid maldistribution)
2. Particle - scale (local catalyst incomplete wetting)
• Internal particle incomplete contacting is unlikely in the
absence of highly exothermic reactions
• External particle incomplete contacting is likely in the
trickle - flow regime when Lm < 5 kg / m2 - s
41
External Contacting Efficiency
Low Gas-Liquid Interaction Regime
CE = 1.617 ReL0.146 GaL 0.9711
or
L < 5 kg / m2 s
0.224
CE = 1.021 D
CE = 1.0
L
> 5 kg / m2 s
where: D = Dynamic liquid saturation
D = LD / B
42
Liquid-Solid Contacting - Summary
Combining flow pattern deviations from ideal liquid
plug flow, and incomplete catalyst wetting:
• Liquid not in plug flow and there is no radial mixing, but all
catalyst is wetted
• Liquid not in plug flow and extensive radial mixing, and all
catalyst is wetted
• Partial external wetting of catalyst
• Partial internal wetting of catalyst
Correlations for liquid-solid contacting:
• Ruecker & Agkerman (1987), Ring & Missen (1991), Al-Dahhan
& Dudukovic (1995)
43
Intraparticle Diffusion Resistance
Conventional Thiele-modulus/effectiveness factor
approach needs to be modified to account for
partial external and intraparticle wetting:
• Mills & Dudukovic (1980) solved the diffusion-reaction equations
for partial external wetting for slab, cylinder and sphere-shaped
particles
• The numerical solution can be approximated by weighted
average of effectiveness factor of totally wetted and totally dry
particles, the weighting factor being the contacting efficiency
TB = CE W + (1- CE) NW
• Internal wetting effects have been largely ignored
44
Catalyst Effectiveness Factor
for a Differential TBR
• Assume:
(1) Gas-limiting or volatile liquid-limiting reactant
(2) First-order reaction
(3) Incomplete external wetting, complete internal wetting
• Approximate solution only possible for large modulus p
45
Overall Effectiveness Factor for a
Trickle-Bed Reactor (limiting reactant in
Gas phase), O
o =
CE
P
BiW
2
+
P
tanh P
te rm due to inter nal pore diffus ion
+ exte rnal m ass tr ans fer
CE x
through the active ly w e tte d surface
+
of the catalyst pe lle t
+
(1 - CE )
P 2
P
+
BiD
tanh P
te rm due to inter nal pore diffus ion
+ exte rnal m ass tr ansfe r
(1- ) x
through the inactively w e tte d surf ace
CE
of the catalys t pe llet
Increasing ηCE decreases conversion !
LHSV based scale-up alone is not suitable !
CE = external liquid-solid contacting efficiency
CE < 1 for cocurrent downflow; CE = 1 for upflow
46
Overall Effectiveness Factor for a
Trickle-Bed Reactor, (limiting reactant
in liquid phase) O
o =
CE
P
P
+
BiW
tanh ( P / CE )
2
1
p k1
P Ls
De
H k L
Bi w A gs s
De
Bi D
k gls Ls
Bi w
k s Ls
De
1
1/2
Increasing ηCE increases conversion !
LHSV based scale-up is suitable !
De
47
Trickle-Bed Reactor
Catalyst Effectiveness Factors
Overall effectiveness factor, O
• Both external and internal transport resistances
are included
VP
r V dV
O =
0
VP r Vs
observed average rate in the pellet
=
rate obtained if all the pellet exists
at the bulk conditions adjacent to the pellet
but outside the boundary layer around it
48
Comparison of Effectiveness Factors Calculated
From Previous approximate Solution and Actual Numerical
Simulation
49
Rigorous Multicomponent Diffusion Modeling
- Gas Liquid Interphase Function Vector N1GL ctl {[ L ][k Lo ][]}1, j ( x Ij x Lj ) x1 (q) / x
j
o
I
L
N GL c
2
tl {[ L ][k L ][ ]}2 , j ( x j x j ) x2 ( q ) / x
j
.
.
.
N GL c
o
I
L
{[ L ][k L ][]}nc 1, j ( x j x j ) xnc 1 (q) / x
nc 1 tl
j
GL
o
V
I
N
c
1
tg {[ G ][k G ]}1, j ( y j y j ) y1 ( q ) / y
j
GL
o
V
I
N 2 ctg {[ G ][kG ]}2, j ( y j y j ) y2 (q ) / y
j
.
FGL ( z , t )
.
.
o
V
I
N GL c
{[ G ][kG ]}nc 1, j ( y j y j ) ync 1 (q ) / y
nc 1 tg
j
I
I
y1 K1 x1
I
y2I K 2 x21
.
yncI K nc xncI
I
I
I
I
x1 x2 x3 ...xnc 1
y1I y2I y3I ...yncI 1
n
GL
G
L
qG qL N i ( H i H i )
i 1
3nc 1
Khadilkar et al., 1998
50
CREL
General Geometry
• Discuss MFS use here
• See muthana. Eusebio paper
51
Level III TBR Model
-Catalyst Scale EquationsExternally Half Wetted,
Partially Liquid Filled Pellet
Liquid Filled Zone
d
N iLC i Ri ,liq
dx
NiLC
CiLC C nc 1
d C
NtL {[ BL ]1[]
CiL }i , j
C
CtL
dx
j 1
d N iLC H iLC
d2
keL 2 TLC
0
dx
dx
| Wet Zone
| Dry Zone |
Lc
Gas Filled Zone
d
C
N iG
i Ri , gas
dx
C
NiG
keG
C
nc
CiG
d C
C
N
{[ BG ]1
CiG }i , j
tG
C
CtG
dx
j 1
d 2 C d NiG H iG
TG
0
dx2
dx
C
Khadilkar et al., 1998
C
Intra-catalyst G-L Interface
Continuity of temperature,
mass and energy fluxes,
and equilibrium relations
for all species
Liquid imbibition velocity
v=NCtL/CCtL=(RP2/8 L)(P(x=Lc)-P(x=)+2cos/RP)
52
CREL
Methods of Determining Contacting
Efficiency
• Tracer Method
• Chemical Reaction Method
53
Prediction of TBR Multiplicity Effects
• Hysteresis Effects Predicted
1.2
• Two Distinct Rate Branches Predicted
(as Observed by Hanika, 1975)
1
Conversion
0.8
• Branch Continuation, Ignition and
Extinction Points
0.6
Wet Branch(Exp t)
0.4
• Wet Branch Conversion (~30 %)
Dry Branch (Exp t)
Wet Branch (L-II)
Dry Branch (L-II)
0.2
• Dry Branch Conversion (> 95 %)
Wet Branch, (L-III)
Dry Branch (L-III)
0
0
5
10
Hydrogen Feed Ratio, N
15
• Continuation of the dry branch
• Thermal conductivity - L II model
• Intracatalyst interface location-LIII
model
System: Cyclohexene hydrogenation
54
CREL
Three Types of Catalyst for Highly
Exothermic Reactions
55
Nonvolatile Liquid-Limiting Reactant
Completely Wetted Catalyst ( ce = F i =1 )
Reaction : A (gas) + B (liquid) = P (liquid)
• Kinetic rate
: kVBS
( mol / m3 catalyst - s )
( per unit catalyst volume )
• Rate in catalyst
: kvPBS ( 1- B ) ( mol / m3 reactor - s )
( per unit reactor volume )
• Transport rate
: kLS ap BL - BS ) ( mol / m3 reactor - s )
( per unit reactor volume )
56
Overall or Apparent Reaction Rate
Liquid-Limiting Reactant ( mol / m3 reactor - s )
P kV (1 - B ) BL = k app BL =
BL
1
k LS aP
+
1
P kV (1 - B )
57
Plug-Flow Model for Scale - Up
Nonvolatile liquid, 1st order reaction
XB
3, 600 (1 - B ) k app
= 1 - exp
LHSV
3,600 uL
LR
where:
LHSV =
Using :
• Same catalyst activity
• Same size particles
• Same packing procedure ( B )
• Same feed
• Same Temperature
58
Gaseous-Limiting Reactant
Completely Wetted Catalyst ( ce = F i =1 )
Reaction : A (gas) + B (liquid) = P (liquid)
• Kinetic rate
: kVAS
( mol / m3 cat - s )
( per unit catalyst volume )
• Rate in catalyst
: kv ( 1- B )PAS ( mol / m3 reactor - s )
( per unit reactor volume )
• Transport rate
:
( mol / m3 reactor - s )
( per unit reactor volume )
1. Gas - liquid KLaB ( AG /HA - AL)
2. Liquid-solid kLS aP AL - AS )
59
Overall or Apparent Reaction Rate
Gas Limiting Reactant (mol / m3 reactor - s )
A
A
P kV (1 - B ) G = k app G =
H A
H A
AG
H A
1
KL aB
+
1
k LS aP
+
1
P kV (1 - B )
60
Reactor Performance for a Gas-Limiting
Reaction with First-order Reaction
A (gas) + B (liquid)
XB =
P (liquid)
A * (1 - B ) 3600 k app
BLO LHSV
where:
k app =
CE
2
BiWG
+
tanh
(1 - CE ) tanh
+
An increase in CE may decrease kapp so that equal LHSV for
scale-up may not work, i.e., if kapp decreases as uL increases.
61
Scale-up Methodology for a
Gas-Limiting Reaction
• Keep same liquid hourly space velocity (LHSV)
• Keep same ratio of liquid to gas mass velocities (L / G )
• Keep same packed-bed length (i.e., same L (uL) )
These criteria are often impractical to implement.
Hence, a fundamental reactor model that captures the
key phenomena is needed for scale-up or scale-down.
62
TBR Scale - Up for Aldehyde Hydrogenation
Scale - up done based on equal LHSV with disastrous
results
Data
Plant
Laboratory
Height (m)
19.4
0.235
Diameter (m)
0.455
0.0341
LHSV (h-1)
1.3
1.3
UL (LHSV) (mh-1)
26
0.26
H2 flow (STD) (m3h-1)
1000
-
GHSV
-
312
Pressure (bar)
65 - 80
70
Temperature (oC)
110
110
Bed porosity
0.425
0.425
Catalyst tablets
3 / 16 “ x 1 /8 “
(Vp / SP = 0.31 cm )
Conversion (XB)
0.40
0.90
63
Scale-up & Scale-down from Pilot Plant to Commercial
Reactor
• Catalyst orientation (flat surface preferred)
• Addition of fines in pilot plant to simulate good
liquid distribution and absence of wall effects
•
• Reactor internals
- Inlet distribution
- Quench zones with redistribution
- Outlet collector geometry
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