FACULTY OF ENGINEERING
Applications of Single-Event Modeling in theApplications of
Single-Event Modeling in theProduction of Liquid Fuels Through
HydrocrackingProduction of Liquid Fuels Through Hydrocracking
Bart D. Vandegehuchte, Joris W. Thybaut, Christophe Detavernier,
Johan A. Martens, Guy B. MarinBart D. Vandegehuchte, Joris W.
Thybaut, Christophe Detavernier, Johan A. Martens, Guy B. Marin
http://www.lct.Ugent.be E-mail:
[email protected] for Chemical Technology,
Krijgslaan 281 (S5), B-9000 Ghent, Belgiumhttp://www.lct.Ugent.be
E-mail: [email protected]
MODEL DEVELOPMENTINTRODUCTION MODEL DEVELOPMENTINTRODUCTION
Reaction Network• Hydrocracking as an important refinery
conversion process:
Fluid phase Zeolite pores Metal function
+ +
Acid function– Yields high-quality fuels with very
low sulfur and aromatics content.
physisorption (de)hydrogenation (de)protonation
+ +
isomerization
low sulfur and aromatics content.
– Transforms heavier compounds
into smaller and branched+
cracking
+
+
Single-event Concept
into smaller and branched
hydrocarbons.
– Plays a significant part in theSingle-event Concept
1. Reaction families defined according to the type of
elementary
reaction and the type of the carbenium ions involved.
Subsequently,
– Plays a significant part in the
production of liquid fuels from
alternative materials.reaction and the type of the carbenium
ions involved. Subsequently,
a unique single-event rate coefficient, , introduced per
family.
2. Variations in actual and single-event rate coefficients,
originating
k~Biomass/ Coal
Natural gas
gasification
steam reforming
Synthesis gas
CO H
Fischer-Tropsch
synthesis
Heavy n-alkanes hydrocracking Lighter hydrocarbons
alternative materials.
2. Variations in actual and single-event rate coefficients,
originating
from symmetry differences between reactant and transition
state,
accounted for by the number
Natural gas steam reforming CO H2synthesis
• Single-Event MicroKinetic (SEMK) modeling identified as a
versatile
tool in reaction path analysis and process optimization.
accounted for by the number
of single events, ne.
tool in reaction path analysis and process optimization.
• In this work: Application of the SEMK methodology to the
assessment
of catalytic modifications, caused by the deposition of an
additional+
+k1
k2k1 = 2 k2
s/t)(s/t;s/t)(s/t; iso/craiso/cra k~nk e=⇒
of catalytic modifications, caused by the deposition of an
additional
aluminum layer, via regression on hydrocracking data of
n-decane.
REGRESSION ANALYSIS
Rate equation
2E-08
NH3-TPD data
100
Tota
l co
nv
ers
ion
(%
)
C KC k~n 1
−
ppKK
Catalytic activity
5E-09
1E-08
1.5E-08
Ion
cu
rre
nt
(A)
25
50
75
Tota
l co
nv
ers
ion
(%
)
( )
∑
+∑+= −
HpLdeh
pL
ppKKpK
r
1 1
1
2Csat
Csat
Kprot
KprotCacid k~ne
1
2
−HpLdeh ppKK
0
5E-09
50 150 250 350 450 550 650 750
Ion
cu
rre
nt
(A)
Temperature (°C)
0
25
135 155 175 195 215 235 255
Tota
l co
nv
ers
ion
(%
)
Temperature (°C)
( )
∑++∑+
pL
pLpK
pK 1
1 1 2
Temperature (°C)
N2 adsorption data
200
g-1
)
• Kdeh calculated from thermodynamic data.
• Heats of physisorption unaffected by
Temperature (°C)
( ) ( )
−=R
S
RT
HK
protprotprot
Δexp
s/tΔexps/t
160
180
Mic
rop
ore
vo
lum
e (
cm3
g
• Heats of physisorption unaffected by
treatment → KL from CBV712.
• independent of catalyst → required
• ΔHprot as a direct measurement of individual
acid site strength.
( )
=RRT
Kprot expexps/t
k~
120
140
0 500 1000 1500 2000 2500 3000 3500 4000
Mic
rop
ore
vo
lum
e (
cm
• independent of catalyst → required
activation energies determined from
previous works.†
acid site strength.
• ΔHprot(s) and ΔHprot(t) adjusted during
regression.
k~
0 500 1000 1500 2000 2500 3000 3500 4000
Al deposition time (s)previous works.† regression.
SIMULATION RESULTS CONCLUSIONSSIMULATION RESULTS
Al deposition Cacid Csat ΔHprot(s) ΔHprot(t)
CONCLUSIONS
• With use of the SEMK methodology, an excellent agreement
istime (s)
acid
(µmol g-1)sat
(µmol g-1)prot
(kJ mol-1)prot
(kJ mol-1)
CBV712 805 826 -67.7 -98.3
Modified 1 150 540 852 -68.2 -97.5
• With use of the SEMK methodology, an excellent agreement
is
obtained between experimental and model results.
• Three catalyst properties are affected by the
treatment:Modified 1 150 540 852 -68.2 -97.5Modified 2 300 572 656
-64.7 -94.6
Modified 3 3600 812 470 -62.3 -91.9
• Three catalyst properties are affected by the treatment:
– Capacity for physisorbed species
– Capacity for chemisorbed species– Capacity for chemisorbed
species
– Acid site strength
• The treatment induces coverage of the original framework acid
sites75
100
Yie
ld (
%)
CBV712
Total conversion
75
100
Yie
ld (
%)
Mod 1
• The treatment induces coverage of the original framework acid
sites
and allows the additional aluminum layer to form as a new
catalytic
phase.25
50
Yie
ld (
%)
Total conversion
Isomerization yield
Cracking yield25
50
Yie
ld (
%)
phase.
• The SEMK model has been demonstrated to be a useful tool in
the
assessment of catalytic modifications and can be extended to
the
0
130 150 170 190 210 230
Temperature (°C)
0
130 150 170 190 210 230
Temperature (°C)
100Mod 2
100Mod 3
A
assessment of catalytic modifications and can be extended to
the
synthesis of new and advanced materials.50
75
Yie
ld (
%)
Mod 2
50
75
Yie
ld (
%)
Mod 3
ACKNOWLEDGEMENTS
The Special Research Fund (Bijzonder OnderzoeksFonds) and
the0
25
145 165 185 205 225 245 265
Yie
ld (
%)
0
25
140 160 180 200 220 240 260
Yie
ld (
%)
† J.W. Thybaut, C.S. Laxmi Narasimhan, G.B. Marin, J.F.M.
Denayer, G.V. Baron, P.A. Jacobs, and J.A. Martens, Cat. Let. 94
(2004) 81-88
The Special Research Fund (Bijzonder OnderzoeksFonds) and
the
Belgian Government (IAP) are acknowledged for financial
support.
145 165 185 205 225 245 265
Temperature (°C)
140 160 180 200 220 240 260
Temperature (°C)
