Rheologygy g modeling of a Multiphase Detergent Processing · Not all that glitters is goldNot all...
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Comsol Conference, Milano October 14 – 16, 2009 Rheology modeling of a Multiphase Detergent Processing Vincenzo Guida Vincenzo Guida Pomezia F&HC R&D Pomezia F&HC R&D
Transcript of Rheologygy g modeling of a Multiphase Detergent Processing · Not all that glitters is goldNot all...
Comsol Conference, Milano October 14 – 16, 2009
Rheology modeling of a gy gMultiphase Detergent Processing
Vincenzo GuidaVincenzo Guida
Pomezia F&HC R&D Pomezia F&HC R&D
Background
5 micron
100 micron
Rheology of FP
10.00 10.00
0.1 Pa applied stress
4.500
Equilibrium parameters definition 0Pa 001-0002f
2 500
3.000
3.500
4.000
Pa.
s)
1 sec-1 constant shear experiment
(lab made unsheared sample)
G' (
Pa)
G'' (P
a)
1.000
1.500
2.000
2.500
visc
osity
(P
(lab made unsheared sample)
1.000 50.00ang. frequency (rad/s)0 00 20.00 40.00 60.00 80.00 100.0 120.0 140.0
time (s)
0
0.5000
Thixotropic MaterialUnder flow
Weak elastic gel at rest
Detergent processing
Shear Shear
Industrial problems for detergents f t imanufacturing
• Predict flow of detergents– Size pumps and pipelines– Calculate pressure drop in mixing devices,
packing nozzles, manifold etc…
• Predict finished product propertiesA hi d t i d i t t– Achieve a determined microstructure
– Predict rheology, stability, apperance
Flow problem: modeling thixotropy
Product rheologyProduct rheologyViscosity Curve
100
10
sity
(Pa.
s)
10.01 0.1 1 10 100
Visc
os
0.1
Shear Rate (sec 1)Shear Rate (sec-1)
ThixotropypyViscosity evolution versus time at shear
100
1000Viscosity at 0.1 sec-1Viscosity at 1 sec-1Viscosity at 10 sec-1Viscosity at 100 sec-1
10
ty (P
a*se
c)
0 1
1
Visc
osit
0.01
0.1
0 2 4 6 8 10 12 14 16
Time (min)
Thixotropy experimental investigation
Viscosity at 0.1 sec-1 after 15 minutes at a given shear stress
60
40
50
60
(Pa.
s)
20
30
Visc
osity
(
0
10
0 20 40 60 80 100 120
Applied Shear stress (Pa)Applied Shear stress (Pa)
eqc 1
critic
q
10
Thixotropy experimental investigationThixotropy experimental investigation
Viscosity at 0.1 sec-1 after x minutes at high stress
80
90
100
50
60
70
ty (P
a*se
c)
20 Pa50 Pa
20
30
40
Visc
osit 80 Pa
0
10
20
0 2 4 6 8 10 12 14 16
Time at high stress (minutes)
Rheology modelRheology model
n
cKK
K
eqccbaddc
KK
)(
0
neq
eq
c
dt
1
)(
crit1
Modification of Moore’s model
3D implementation in Comsol3D implementation in ComsolMomentum balanceMomentum balance
Rheology constitutive equationRheology constitutive equation
C i l f i iConservation law for connectivity
n
wvwuvuwvuk yzxzxyzyx
222222 222444
21
eqccbaR )(
Fluid dynamics simulationFluid dynamics simulation
Simulation ResultsSimulation Results
Microstructure problem: modeling gelation
After Processing22 0
25.00
22 0
25.00
15.00
17.50
20.00
22.50
Pa)
15.00
17.50
20.00
22.50
G''
Gelationh
5.000
7.500
10.00
12.50
G' (
P
5.000
7.500
10.00
12.50 (Pa)
Time sweep oscillation 10 Hz 0.1 Pa
Lab made Product sheared 30 seconds at 100 Pa
happens0 25.00 50.00 75.00 100.0 125.0 150.0 175.0 200.0
time (s)
0
2.500
0
2.500
Destructuring rate 30Pa 10min 001-0002oDestructuring rate 30Pa 10min 001-0002o, Time sweep step
100.0 100.0
10.00
G' (
Pa)
10.00
G'' (P
a)
Time sweep oscillation 10 rad/sec 0.1 Pa
GelationDoes not happen
0 200.0 400.0 600.0 800.0 1000time (s)
1.000 1.000
Lab made Product sheared 600 seconds at 30Pa
Rheological Characterization
Constant Stress Flow Time Sweep Oscillation = 5, 10, 30. 50 100 Pa t = 30 60 180 600 sec
= 0 -900 sect =, 30, 60, 180, 600 sec
G' versus applied shear stress (10 Minutes) before and after recovery
G' after recovery versus time for different applied shear stress10 Pa30 Parecovery
20
25
Lab G'Lab G' after 15 minutes 21
23
2530 Pa50 Pa100 Pa
10
15
G'
13
15
17
19
G' (
Pa)
0
5
0 20 40 60 80 100 120Applied Stress
9
11
0 10 20 30 40 50 60 70
Shear Time
Empirical modeling
X1
Fraction of t d
X2
Fraction of
X3
Fraction of connected
rodsnot connected
rodsnematic
rods
1 )( XXbdX
2
221111
)()(
)(
XbaXaXbadX
XaXbadt
d
213
23322111
1
)()(
XXX
XbaXaXbadt
Estimating Kinetics from Rheologyg gy2 simple rules:• Elastic modulus depends only on phase 1
G’ = G’0 * X1G G 0 X1• After 15 minutes time sweep X2 =0
As flow stops:As flow stops: X1 = b/a, X2, = d/a
After recovery:X1 = c/a, X2 = 0
10 P
Model fitting: maximum likelihood parameter estimation
10 Pa 30 Pa
50 Pa 100 Pa
Gelification predictionTanDelta
Gelification prediction
44.5
5
22.5
33.5
TanDelta
00.5
11.5
00 0.2 0.4 0.6 0.8 1 1.2X1
Area of interest for manufacturingArea of interest for manufacturing
ConclusionsConclusions
• Comsol is a very flexible platform ideal toComsol is a very flexible platform, ideal to model rheology modification under flow
• Analogy with reactive flows allows• Analogy with reactive flows allows modeling of both thixotropy and gelation with decent level of accuracy andwith decent level of accuracy and predictabilityIt i ibl t i t t t 1 D• It is possible, a certain extent, to use 1 D rheology to extrapolate 3D behavior
Not all that glitters is goldNot all that glitters is gold• Not everything scales with total shear rate!Not everything scales with total shear rate!• Need at least to distinguish the extensional and
the pure shear components p p• Single or double step reaction model are too
crude, need to move to population balance, p p• Need to move from General viscous to Visco-
elastic• Need to describe the rods incorporation process
(mixing + aggregates break up)
Thank You!
