How to study and to optimize continuous industrial Gas-Liquid-Solid reactor under hydrogen presssure. Nextlab 2014
April 3rd 2014
E Lecomte-Norrant
GPS/ ITS Dr
NEXTLAB 2014 IFPEN April 3rd Rueil Malmaison
ן Context of the problem: a complex G/L/S continuous reactor...
ן Data acquisition: development of tools Kinetic rate
Hydrodynamic data by radioactive tracers
Volumetric ratio of each phase by gamma rays
Profile of concentration of raw material and H2 in liquid phase
ן Determination of gas/liquid mass transfer coefficient with the validation of model
ן Conclusion: Optimization of operating conditions
Continuous Gas-Liquid-Solid industrial reactor under H2.
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NEXTLAB 2014 IFPEN April 3rd Rueil Malmaison
AGENDA
Continuous Gas-Liquid-Solid industrial reactor under H2 3
Context: industrial reactor...
Since yesterday, a lot of sciences with new tools concerning the “ laboratory of the future” to develop our future industrial processes...
BUT Do not forget...
We have some old industrial processes which work for more than 20 years , and no one knows exactly how they work.
My target is How to improve or to solve some problems on these chemical reactors?
So development of tools to use directly on existing industrial are required, by taking account all safety conditions.
It is the industrial reality....for old processes.
I want to present to you one of these examples.
A complex G/L/S continuous reactor...
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Principe of the industrial reactor
I
Gas/Liquid/solid Bubble column N°1
Gas/Liquid/solid Bubble column N°2
Liquid/solid Columns N° 1 & 2
Cyclone
Settling tank
H2 H2
Raw material catalyst
NEXTLAB 2014 IFPEN April 3rd Rueil Malmaison
Cyclone
Settling tank
Gas/Liquid/solid Bubble column
Liquid/solid column
Recycle of H2
H2
Raw material Catalyst
Product
Old catalyst
A complex G/L/S continuous reactor... 5
How to optimize operating conditions?
What we know?
• The inlet flow rate of H2, raw material with the outlet flow of final product
• The inlet/outlet temperatures of the jacket and one temperature in the reactor
• The size and design of all equipment.
What we do not know? But we must know
• The velocity of each phase
• The volumetric ratio of each phase
• The axial dispersion of each phase
• Gas-liquid mass transfer flux
• Liquid-solid mass transfer flux
• Concentration of raw material, intermediates and by-products
• the kinetic rate of main reactions with by-product reactions
in each part of the reactor
NEXTLAB 2014 IFPEN April 3rd Rueil Malmaison
G/L/S reactor : Kinetic rate 6
Runs in laboratory in batch way..
2 main consecutive reactions: Di-nitrile to Di-amine
DN + 2 H2 - MN
MN + 2H2 DA
Langmuir Hinshelwood model
DN---> MN : Rm1 = ] [ 20.5
H.sHMN.sMNDNsDN
sH,HDNsDN1
] )C (K 1 C K C K [1C K C K k
+∗++
MN---> DA : Rm2 = ] [ 20.5H.sHMN.sMNDNsDN
sH,HsMN,MN2
] )C (K 1 C K C K [1 C K C K k
+∗++
NEXTLAB 2014 IFPEN April 3rd Rueil Malmaison
kl = 3475 e -42900/RT kmol DN/kg/s ∆E1 = 42.9 kJ / mol k2 = 6895 e -45619/RT kmol MN/kg/s ∆E2 = 45.6 kJ / mol KDN =9.1 e+170/RT m3/kmol ∆ΗDN = -0.17 kJ/mol KMN =66.2 e-6641/RT m3/kmol ∆ΗMN = 6.6 kJ/mol KH =2.5 e+9080/RT m3/kmol ∆ΗH = -9.1 kJ/mol ∆H : Heat of adsorption of reactants.
A complex G/L/S continuous reactor... 7
How to optimize operating conditions?
What we do not know? But we must know
• the kinetic rate of main reactions with by-product reactions
• The velocity of each phase
• The ratio of each phase
• The axial dispersion of each phase
• Gas-liquid mass transfer flux
• Liquid-solid mass transfer flux
• Concentration of raw material, intermediates, by-products and H2 in Liquid phase
in each part of the reactor
How to get data?
• Runs in lab
• Radio active tracers on each phase
• To check
• Tool made home ...
NEXTLAB 2014 IFPEN April 3rd Rueil Malmaison
Tool box... 8
Radio active tracers to measure...
•Velocity of each phase
•Volumetric Ratio of each phase
•Axial dispersion of each phase
Phase Tracer Half life Energy Mass injected
Gas phase Argon 41 110 mn 1.29Mev 12ml Nm3
Gas phase Krypton 79
34 hours
0.511Mev 12ml Nm3
Liquid phase
Br82
(NH4Br) 36
hours 1.47;0.78;0.62;0.5
5Mev
0.2-0.5g
Solid phase
Ni65 2.56 hours
1.49; 1.11 Mev
8-10g
NEXTLAB 2014 IFPEN April 3rd Rueil Malmaison
Choice of tracers
Work done with the collaboration of CEA
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4
8
5
3
1
9 Outlet of product
7
10
2
Solubility of gas tracer to compare with H2 solubility 9
Bunsen Coef.(ml TPN / L/ bar)
H2 31 49
Ar 92-96 89-91
Kr 250 -256 192-193
T= 20°C T= 80°C
Krypton is 2 more time soluble that Argon in our mixture
Results with radio active tracers... 10
Probe N°3
Probe N°4 Probe N°5 Probe N°6
Probe N°3
Probe N°1
Probe N°4 Probe N°5 Probe N°6
Liquid phase
Gas phase
NEXTLAB 2014 IFPEN April 3rd Rueil Malmaison
Results with radio active tracers... 11
NEXTLAB 2014 IFPEN April 3rd Rueil Malmaison
Probe N°8: top of the L-S column For liquid tracer and solid tracer
Probe N°10 Outlet of product
Treatment of data : Analysis of the two signals inlet and outlet; classical method
12
Algorithm of the software:.
Reading of inlet and outlet data with treatment of data to remove parasites
To transfer data in FOURIER space
Réinitialisation . Initialization of Pe and τ in the transfer function. of Pe and τ
Calculation of outlet curve in FOURIER space to get the outlet theoretical curve
Comparison of the experimental outlet curve with the calculated theoretical curve with the less square method to minimize the residues
Good values of Pe and τ
Continuous Gas-Liquid-Solid industrial reactor under H2 13
Results Radio active tracers for G/L/S bubble column
Reproductibility:
NEXTLAB 2014 IFPEN April 3rd Rueil Malmaison
Run Tracer ProbesVelocity
(m/s)
Diffusion Coefficient
(m2/s)
Peclet Number
N°1 Argon 41 [ 3 - 6 ] 5.1 0.5 168N°2 Argon 41 [ 3 - 6 ] 5.1 0.5 170N°3 Krypton 79 [ 3 - 6 ] 5 0.56 160N°4 Nickel 65 [ 1 - 6 ] 4.47 0.27 300N°5 Brome 82 [ 1 - 6 ] 4.45 0.25 320
Comments • Reproducibility has been checked
• Velocity of liquid phase and solid phase are the same
• Small difference between gas velocity and L/S Velocity
• Plug flow reactor can be taken as model
Continuous Gas-Liquid-Solid industrial reactor under H2 14
Results Radio active tracers for L/S column
Comments
• Precision on Diffusion coef. is not very precise (< 20%)
• Precision on velocity is accurate (< 2%)
• Velocity of liquid phase and solid phase are close
• Small difference between L/S Velocity and Gas velocity
• Plug flow reactor can be taken as model
Run TracerVelocity
(m/s)
Diffusion Coefficient
(m2/s)
Peclet Number
N°1 Argon 41 3.6 0.14 450N°2 Argon 41 3.6 0.19 387N°3 Krypton 79 3.75 0.2 387N°4 Nickel 65 3.83 0.18 550N°5 Brome 82 3.85 0.2 394
Continuous Gas-Liquid-Solid industrial reactor under H2 15
Results Radio active tracers for cyclone
Comments
• Cross flow in cyclone between the 2 columns
• Residence time of liquid or solid phase is 1.06s
• A small flow goes to decanter : Centrifuge effect...
Cyclone
G-L-S Column
Solid : 25%Liquid: 28%Solid : 68%
Liquid: 68%
Solid : 7%Liquid: 4%
Solid : 100%Liquid: 100%
L-S ColumnL-S Column
To summarize... With radio active tracers... 16
JAMBE MONTANTE
ε gaz= 0.266 Qgaz= 345 m3/h ε liq= 0.71 Qliq= 830 m3/h ε sol= 0.023 Qsol= 26.9 m3/h Da gaz= 0.50m2 /s u gaz= 5.1m/s Da liq= 0.23m2 /s u liq= 4.5m/s Da sol= 0.27m2 /s u sol= 4.5m/s
JAMBE DESCENDANTE
ε gaz= 0.09 Qgaz= 80 m3/h ε liq= 0.88 Qliq= 796.8 m3/h ε sol= 0.026 Qsol= 25 m3/h Da gaz= 0.15m2 /s u gaz= 3.65m/s Da liq= 0.2 m2 /s u liq= 3.85m/s Da sol= 0.12m2 /s u sol= 3.85m/s
Q gaz = 7000Nm3/h Q ADN = 32.5 Tonnes/h Q liq = 2.3 m3/h
Q HMD = 70 Tonnes/jour
DECANTEUR Qliq= 66.3 m3/h Qsol= 3.76 m3/h u liq= 2.1mm/s
Retour Qliq= 27 m3/h
Qsol= 1.68 m3/h u liq= 3.83m/s
Pot de soutirage
CYCLONE τsol=τliq=1.06s
ε Taux de rétention τ Temps de séjour Da Dispersion axiale u Vitesse interstitielle Q Debit
G-L-S Column
L-S Column
Product
Q DN Q Catalyst
Q H2
Back to GLS column
Decanter
ε : Volumetric fraction, τ Residence time Da : Axial dispersion U : velocity
Decanter
Continuous Gas-Liquid-Solid industrial reactor under H2 17
To check the global density by gamma rays...why?
Several same reactors with a different behaviors: A shutdown of one reactor must be done each 6 months (to compare with others : 18months) to clean the reactor : problem of heat transfer.
Difference of behavior when I took samples to measure raw material concentration and Soluble H2. (See later)
The intensity I of gamma ray captured by the detector, through a material of a thickness x and a density D is I= I0 e-(µ * x * D)
Work done by Process Vision service
ן Results : data of global density by gamma rays as function of 3 different flow rate of H2 ( close to Nominal flow rate)
Continuous Gas-Liquid-Solid industrial reactor under H2 18
NEXTLAB 2014 IFPEN April 3rd Rueil Malmaison
Probe Probe
0.7 N 1 N 1.2 N 0.7 N 1 N 1.2 N
1 0.89 0.75-0.96 0.88 1.04 1 1.2 12 0.98 0.87 0.9 1.12 1.12 1.1 23 0.98 0.92 0.9 1.1 1.1 1.09 34 0.94 0.9 0.88 1.13 1.15 1.13 45 1 0.91 0.85 1.15 1.17 1.13 5
7 0.93 0.7 0.778 1.04 1.04 1.01 0.97-1.04 0.98-1.03 0.98-1.04 109 0.82-1.09 0.85-1.07 0.84-1.04 1.14 1.16 1.12 11
Density of Bubble column Density of L-S ColumnFlowrate % Nominal flow N Flowrate % Nominal flow N
Comments • Density of G/L/S is lower than Density of L/S column • To check the accuracy of data
Continuous Gas-Liquid-Solid industrial reactor under H2 19
Results concerning global density by gamma rays of the reactor which works differently...
Comments
• Difference of density: different values between upright and horizontal pipe.
• Cyclone works like a spillway which induces a bad separation of Gas from L/S phases;
• Low difference of density between G/L/S column and L/S column, which reduces the velocities of each phases and increases clogging.
Probe Probe
1a upright 0.6 0.69 upright 1a
1a Horizontal 0.67 0.73 Horizontal 1a
1b upright 0.73 0.69 upright 1b
1b Horizontal 0.8 0.78 Horizontal 1b
Density of mixture at te top of the columns
Density of mixture at te top of the columns
ן How can we explain this problem and How to solve it?
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Outlet of product
After several weeks , I discovered that a small pipe in the receipt tank of product, has been cut at the entrance of the tank by the maintenance...
We add a pipe with a length of 1 meter and we solve the problem: we equilibrate the level of liquid in cyclone....
Continuous Gas-Liquid-Solid industrial reactor under H2 21
Profile of concentration of raw material and H2 in liquid phase
PPP
Event
Bougie Filtrante
Purge de la prise Echantillon
Bac de récupération
Réacteur
Cellule de mesure
Cellule de séparationLiquide du Gaz/Solide
From Reactor
Filter
Tank to separate Solid and gas from liquid phase
Cell to measure
To purge the sample line from reactor
Tank filled up of water for wastes
Tool made home..
Sample points on the industrial reactor.... 22
Top of G/L/S Column
Top of L/S Column
Different points in the decanter
Bottom of L/S Column
Results of DN and MN concentration at the top of G-L-S Column as function of time to take
samples
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MN DN
Time ( second)
Con
c D
N o
r MN
(ppm
)
X 1000
24 Results of H2 concentration as function of T at different samples points
.
Q gas = N Nm3/h Q Product nominal
Top G/L/S
Top L/S Column
Bottom L/S column
Top of Decanter
To model the industrial reactor: Plug flow reactor 25
Parameter to optimize : Gas/Liquid mass transfer: Kla (s-1)
Evolution of concentration of DN and MN in each part of reactor
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1)
G/L/S Column L/S Column Cyclone
Decanter
Con
c of
DN
& M
N (
ppm
) X
1000
MN
MN
Between inlet DN and H2
Evolution of concentration of Soluble H2 in each part of reactor
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G/L/S Column L/S Column Cyclone
Decanter
Length of reactor (m)
ן Some surprising results...
ן Comments In the L/S column, it is not a Gas/Liquid mass transfer but a
Solid/liquid mass transfer of H2: desorption of H2 from Ra Ni catalyst to the liquid solution; ( Shuttle effect well described in the literature) Be careful to get enough soluble H2 in the liquid phase to avoid
deactivation of catalyst
Determination of Gas/liquid mass transfer 28
Top of G/L/S column
Top of L/S column
Bottom of L/S column
Bottom of Decantor
Error % (H2c-H2m)/ H2c 11% 0.30% 9% 2.50%
G/L/S column
Cyclone L/S column Decanter
Kla (s-1) 0.6 0.4 0.25 (*) 0.02 (*)
Ref Chemical Engineering Science, Vol 47, N°13/14. Pp3597-3604, 1992 By E Lecomte , C.MATHIEU. H. DELMAS and J.JENCK
ן Shuttle effect...
Determination of Gas/liquid mass transfer 29
Gas Bubble
NiRa
Interface Gas/Liquid
Diffusionnel layer
Liquid bulk
Gas Adsorption on solid Particule NiRa
Gas Desorption in the liquid bulk
ן We achieve our target:
To understand the working of industrial reactor
By building the model, we optimize operating conditions to increase the productivity by 10-15% on each reactor in safety way.
Main modification: to introduce raw material and new catalyst close to H2 introduction
We solve the malfunctioning of one reactor.
Thanks to • the plant manager who allowed me to take samples in continuous way.... • CEA for radio active tracers • Process vision service for gamma rays
Conclusion 30
Questions? 31
NEXTLAB 2014 IFPEN April 3rd Rueil Malmaison
Thanks!