PETROCHEMICAL PROMOTERS IN CATALYTIC CRACKING
CT&F - Ciencia, Tecnología y Futuro - Vol. 3 Núm. 5 Dic. 2009 143
PETROCHEMICAL PROMOTERS IN CATALYTIC CRACKING
Maria-Elizabeth Gómez*1, Clemencia Vargas1 and Javier Lizcano2
1 Ecopetrol S.A - Instituto Colombiano del Petróleo, A.A. 4185 Bucaramanga, Santander, Colombia2 UT TIP - Petrolabin, Piedecuesta, Santander, Colombia
e-mail: [email protected]
(Received May 5, 2009; Accepted October10, 2009)
T his study is based on the current scheme followed by a refinery with available Catalytic Cracking capacity to process new feedstocks such as Straight Run Naphtha and Naphthas from FCC. These feedstocks are of pe-trochemical interest to produce Ethane, Ethylene, Propylene, i-Butane, Toluene and Xylene.
To evaluate the potential of these new streams versus the Cracking-charged Residues, it was performed a detailed chemical analysis on the structural groups in carbons [C1-C12] at the reactor product obtained in pilot plant. A catalyst with and without Propylene - Promoter Additive was used.
This study analyzes the differences in the chemical composition of the feedstocks, relating them to the yield of each petrochemical product. Straight Run Naphthas with a high content of Naphthenes, and Paraffines n[C5-C12] and i[C7-C12] are selective to the production of i-Butane and Propane, while Naphthas from FCC with a high content of n[C5-C12]Olefins, i-Olefins, and Aromatics are more selective to Propylene, Toluene, and Xylene.
Concerning Catalytic Cracking of Naphthas, the Additive has similar selectivity for all the petrochemical products, their yields increase by about one point with 4%wt of Additive, while in cracking of Residues, the Additive increases in three
Keywords: propylene, catalytic cracking, i-butane, ethylene, naphthas, petrochemicals, Residues, ZSM-5.
Ciencia, Tecnología y Futuro
* To whom correspondence may be addressed
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MARIA-ELIZABETH GÓMEZ et al.
144
El presente estudio se basa en el esquema actual de una refinería con capacidad disponible en Cracking Catalítico, para procesar nuevas cargas tales como Naftas Vírgenes y Naftas de URC (Unidad de
Propileno, i-Butano, Tolueno y Xilenos.
Para evaluar el Potencial Petroquímico de estas corrientes frente al de los Residuos cargados a Cracking, se realizó un análisis químico detallado de los Grupos Estructurales de los Carbonos [C1-C12] en el producto reactor obtenido en planta piloto, utilizando un catalizador con y sin Aditivo promotor de Propileno.
El estudio analiza las marcadas diferencias en la composición química de las cargas, y las relaciona con los rendimientos de cada uno de los productos petroquímicos. Las Naftas Vírgenes con mayor contenido de Naftenos y de Parafinas n[C5-C12] e i[C7-C12] son selectivas hacia la producción de i-Butano y Propano, mientras que las Naftas de URC con altos contenidos de n[C5-C12] Olefinas, i-Olefinas, y Aromáticos son más selectivas hacia Propileno, Tolueno y Xilenos.
En el craqueo de las Naftas, el Aditivo tiene la misma selectividad para todos los productos petroquímicos, sus rendimientos incrementan en valores cercanos a un punto con 4% peso de Aditivo; mientras que en el craqueo de los Residuos el aditivo incrementa en 3 puntos el rendimiento de Propileno, lo que corresponde
Palabras Clave: propileno, craqueo, i-butano, etileno, naftas, petroquímicos, residuos, ZSM-5
PETROCHEMICAL PROMOTERS IN CATALYTIC CRACKING
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NOMENCLATURE
LCO Light Cycle OilC/O Catalyst / Oil ratioDCR Davison Circulating RiserFCCU Fluid Catalytic Cracking UnitLPGH2 HydrogeniC4 i-ButaneiC5i[C4-C6]i[C7-C12]iPNaft NaphthenesnC2 EthaneC2= EthylenenC3nC3nC4 Butanenn
SimDis Simulated distillation
VGO Vacuum Gas Oil
CT&F - Ciencia, Tecnología y Futuro - Vol. 3 Núm. 5 Dic. 2009
MARIA-ELIZABETH GÓMEZ et al.
INTRODUCTION
Cracking Unit (FCCU) to produce certain products not only depend on its technology or operating conditions, but
determine its potential to produce the desired product.
-
-
-
lene, i-Butane, Toluene and Xylene. Ethane is pyrolized
process
-
THEORETICAL FRAMEWORK
et al. 2008). Based on their decreasing reactivity, these
-tions are used. These catalysts are characterized by the
et al. (2002)
pore size promotes monomolecular reactions only to
hydrocarbon in detail.
EXPERIMENTAL DEVELOPMENT
used in all cases.
PETROCHEMICAL PROMOTERS IN CATALYTIC CRACKING
CT&F - Ciencia, Tecnología y Futuro - Vol. 3 Núm. 5 Dic. 2009
Table 1. Quality of Residues and Naphthas to Pilot Plant
Experimental EquipmentPilot Plant.
continuous Davison Circulating Riser (DCR). The unit
Gas Chromatograph.
-
reported compound.
RESULTS
-
through a mass balance and reported in Table 2 as reactor products.
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MARIA-ELIZABETH GÓMEZ et al.
148
with and without ZSM-5 Additive.
PETROCHEMICAL PROMOTERS IN CATALYTIC CRACKING
CT&F - Ciencia, Tecnología y Futuro - Vol. 3 Núm. 5 Dic. 2009
cracking reactions.
LCO, Slurry, and Coke are also produced in the cata-
Since these Naphthas are injected into the Riser bo-ttom in smaller proportions as compared to Residue, Table
ANALYSIS OF RESULTS
-
is sensitive to variations in C/O severity. The same is
Regarding Naphtha and Residues (Figure 1), Metha-
Even though nC3 is not directly a petrochemical
-pression and recovery zone by less-valuable products.
0
1
2
3
4
5
6
7
nC1 nC2 nC3 nC4 nC5 nC6 nC7 nC8 nC9n C10n
C
11n C12
n-P
ara
ffin
Yie
ld
,%
wt
C/O= 18
C/O= 15
C/O= 11
C/O= 8
C/O= 6
Paraffinic
Figure 1. Distribution profile of n-Paraffin Yields
and Straight Run Naphthas are much more selective to
Naphthenic Naphthas, the higher nC3 yield is due to the -
pounds and Naphthenes. Furthermore, these Naphthenes
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MARIA-ELIZABETH GÓMEZ et al.
150
Craking
3(Olefins) + 3(Parafines) +
Olefin
-
to occur, considering that there is a high concentration
n[C5-C12] (Figures 2b and 3b).
Figure 2. n-Paraffin Yields in Catalytic Cracking of Naphthas
0
1
2
3
4
Base 2%
Adit
4%
Adit
6%
Adit
Base 2%
Adit
4%
Adit
6%
Adit
Orthoflow UOPII
nC
3Y
ie
ld
,%
wt
C/O= 13
C/O= 11
C/O= 10
C/O= 9
C/O= 7
C/O= 6
C/O= 5
0
1
2
3
4
Base 2%
Adit
4%
Adit
6%
Adit
Base 2%
Adit
4%
Adit
6%
Adit
Orthoflow UOPII
n[C
5-C
12
]Y
ie
ld
,%
wt
C/O= 13
C/O= 11
C/O= 10
C/O= 9
C/O= 7
C/O= 6
C/O= 5
Figure 3. n-Paraffin Yields in Catalytic Cracking of Residues
PETROCHEMICAL PROMOTERS IN CATALYTIC CRACKING
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-others, this plant does not process Residues but Light Gas Oil.
-
0
1
2
3
4
5
6
7
8
9
10
I-C4 I-C5 2
methyl
C5
3
methyl
C5
2
methyl
C6
3
methyl
C6
2
methyl
C7
4
methyl
C7
3
methyl
C7
Mono
methyl
C8+
Mono
Ethyl
C8+
§ Others
i-P
ara
ffin
Yie
ld
,%
wt
C/O= 20
C/O= 15
C/O= 11
C/O= 8
C/O= 6
Ortho Pdt
Figure 4. Distribution profile of i-Paraffin Yield
0
1
2
3
4
5
6
7
8
9
10
11
12
No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes
Naphthenic Paraffinic ModIVDBP ModIV Liv UOPII Liv UOPII Pdt Ortho Pdt UOPI Liv
iC
4Y
ie
ld
,%
wt
ADDITIVE
C/O= 20
C/O= 15
C/O= 11
C/O= 8
C/O= 6
FEEDS
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes
Naphthenic Paraffinic ModIVDBP ModIV Liv UOPII Liv UOPII Pdt Ortho Pdt UOPI Liv
i[C
7-C
12
]Y
ie
ld
,%
wt
C/O= 20
C/O= 15
C/O= 11
C/O= 8
C/O= 6
FEEDS
ADDITIVE
Figure 5. i-Paraffin Yields in Catalytic Cracking of Naphthas
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MARIA-ELIZABETH GÓMEZ et al.
152
0
1
2
3
4
Base 2%
Adit
4%
Adit
6%
Adit
Base 2%
Adit
4%
Adit
6%
Adit
Orthoflow UOPII
iC
4Y
ie
ld
,%
wt
C/O= 13
C/O= 11
C/O= 10
C/O= 9
C/O= 7
C/O= 6
C/O= 5
7
8
9
10
11
12
13
14
Base 2%
Adit
4%
Adit
6%
Adit
Base 2%
Adit
4%
Adit
6%
Adit
Orthoflow UOPII
i-P
ara
ffin
Yie
ld
,%
wt
C/O= 13
C/O= 11
C/O= 10
C/O= 9
C/O= 7
C/O= 6
C/O= 5
Figure 6. i-Paraffin Yields in Catalytic Cracking of Residues
cking and due to a higher severity in C/O (Table 2).
vity and sensitivity to changes in C/O severity (Figu-
nC3= production increases in similar proportion to
(Hollander et al.et al., 2008).
(Figure 8).
nC3= yields are similar to that produced by Naphthas
-
(Figure 8a) si
0
1
2
3
4
5
6
7
C2=C3= 1-
C4=
i-
C4=
t-
C4=
c-
C4=
1-
C5=
t2-
C5=
C2-
C5=
1-
C6=
t3-
C6=
c3-
C6=
t2-
C6=
c2-
C6=
n-O
le
fin
Yie
ld
,%
wt
C/O= 20
C/O= 15
C/O= 11
C/O= 8
C/O= 6
Ortho Pdt
0
1
2
3
4
5
6
7
C2=C3= 1-
C4=
i-
C4=
t-
C4=
c-
C4=
1-
C5=
t2-
C5=
C2-
C5=
1-
C6=
t3-
C6=
c3-
C6=
t2-
C6=
c2-
C6=
n-O
le
fin
Yie
ld
,%
wt
C/O= 12
C/O= 11
C/O= 10
C/O= 8
C/O= 6
C/O= 8
C/O= 5
Figure 7. Distribution profile of n-Olefin Yields
PETROCHEMICAL PROMOTERS IN CATALYTIC CRACKING
CT&F - Ciencia, Tecnología y Futuro - Vol. 3 Núm. 5 Dic. 2009 153
Note: The total content of n-Olefin in Straight Run Naphtha is ZERO
a. nC3=
4
5
6
7
8
9
10
No Yes No Yes No Yes No Yes No Yes No
Yes No
Yes No Yes
Naphthenic Paraffinic ModIVDBP ModIV Liv UOPII Liv UOPII Pdt Ortho Pdt UOPI Liv
nC
3=
Yie
ld
,%
wt
C/O= 20
C/O= 15
C/O= 11
C/O= 8
C/O= 6
FEEDS
ADDITIVE
b. n[C5-C12]Olefins
n[C
5-C
12
]O
le
fin
sY
ie
ld
,%
wt
0
1
2
3
4
5
6
7
8
9
10
11
12
No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes
Naphthenic Paraffinic ModIVDBP ModIV Liv UOPII Liv UOPII Pdt Ortho Pdt UOPI Liv
ADDITIVE
C/O= 20
C/O= 15
C/O= 11
C/O= 8
C/O= 6
FEEDS
Figure 8. n-Olefin Yields in Catalytic Cracking of Naphthas
by more than one point (Figure 8a). (Table 2).
-creases yield to Ethylene upon increase in C/O severity.
3
4
5
6
7
8
9
10
11
Base 2%
Adit
4%
Adit
6%
Adit
Base 2%
Adit
4%
Adit
6%
Adit
Orthoflow UOPII
nC
3=
Yie
ld
,%
wt
C/O= 13
C/O= 11
C/O= 10
C/O= 9
C/O= 7
C/O= 6
C/O= 5
b. n[C5-C12]Olefins
0
1
2
3
4
5
Base 2%
Adit
4%
Adit
6%
Adit
Base 2%
Adit
4%
Adit
6%
Adit
Orthoflow UOPII
n[C
5-C
12]O
lefin
sY
ield
,%
wt
C/O= 13
C/O= 11
C/O= 10
C/O= 9
C/O= 7
C/O= 6
C/O= 5
Figure 9. n-Olefin Yields in Catalytic Cracking of Residues
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MARIA-ELIZABETH GÓMEZ et al.
154
0
1
2
3
4
No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes
Naphthenic Paraffinic ModIVDBP ModIV Liv UOPII Liv UOPII Pdt Ortho Pdt UOPI Liv
C2
=Y
ie
ld
,%
wt
ADDITIVE
C/O= 20
C/O= 15
C/O= 11
C/O= 8
C/O= 6
FEEDS
0
1
2
3
4
Base 2%
Adit
4%
Adit
6%
Adit
Base 2%
Adit
4%
Adit
6%
Adit
Orthoflow UOPII
C2
=Y
ie
ld
,%
wt
C/O= 13
C/O= 11
C/O= 10
C/O= 9
C/O= 7
C/O= 6
C/O= 5
-(Hollander et al., 2002).
0
2
4
6
8
10
12
14
16
18
20
22
No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes
Naphthenic Paraffinic ModIVDBP ModIV Liv UOPII Liv UOPII Pdt Ortho Pdt UOPI Liv
i-O
lefin
Yield
,%
wt
ADDITIVE
C/O= 20
C/O= 15
C/O= 11
C/O= 8
C/O= 6
FEEDS
0
1
2
3
4
5
6
7
8
Base 2%
Adit
4%
Adit
6%
Adit
Base 2%
Adit
4%
Adit
6%
Adit
Orthoflow UOPII
i-O
le
fin
Yie
ld
,%
wt
C/O= 13
C/O= 11
C/O= 10
C/O= 9
C/O= 7
C/O= 6
C/O= 5
Figure 11. i-Olefin Yields in Catalytic Cracking of Naphthas and Residues
PETROCHEMICAL PROMOTERS IN CATALYTIC CRACKING
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Naph
-
as C/O severity increases (Figure 12a).
Naphthenic compounds do not interact over the
et al., 2002) (Figure 12b).
-
co-
et al.,
Naphthenes content cause a larger increase in yield
by m-Xylenes. For Residues, Toluene and m-Xylene yields are produced in equal proportion (Figure 13b).
a. Naphtha feedstock
0
1
2
3
4
5
6
No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes
Naphthenic Paraffinic ModIVDBP ModIV Liv UOPII Liv UOPII Pdt Ortho Pdt UOPI Liv
Na
ph
th
en
-O
le
fin
Yie
ld
,%
wt
C/O= 20
C/O= 15
C/O= 11
C/O= 8
C/O= 6
FEEDS
ADDITIVE
b. Residue feedstock
0
1
2
3
4
Base 2%
Adit
4%
Adit
6%
Adit
Base 2%
Adit
4%
Adit
6%
Adit
Orthoflow UOPII
Na
ph
th
en
-O
le
fin
Yie
ld
,%
wt
C/O= 13
C/O= 11
C/O= 10
C/O= 9
C/O= 7
C/O= 6
C/O= 5
Figure 12. Naphthen-Olefin Yields in Catalytic Cracking of Naphthas and Residues
a. Cracking of UOPII Naphtha
0
1
2
3
4
5
6
7
8
9
BenceneToluene ethyl
Bencene
m
Xylene
p
Xylene
o
Xylene
1methyl
3ethyl
Benc
1methyl
4ethyl
Benc
1,3,5
Trimethyl
Benc
1methyl
2ethyl
Benc
1,2,4
Trimethyl
Benc
1,2,3
Trimethyl
Benc
C/O= 19
C/O= 16
C/O= 11
C/O= 9
C/O= 6
UOPII Pdt
Aro
ma
tic
Yie
ld
,%
wt
b. Cracking of UOPII Residue
0,0
0,5
1,0
1,5
2,0
2,5
3,0
BenceneToluene ethyl
Bencene
m
Xylene
p
Xylene
o
Xylene
1methyl
3ethyl
Benc
1methyl
4ethyl
Benc
1,3,5
Trimethyl
Benc
1methyl
2ethyl
Benc
1,2,4
Trimethyl
Benc
1,2,3
Trimethyl
Benc
Aro
ma
tic
Yie
ld
,%
wt
C/O= 12
C/O= 11
C/O= 10
C/O= 8
C/O= 8
C/O= 6
C/O= 5
Figure 13. Distribution profile of Aromatic Yields
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MARIA-ELIZABETH GÓMEZ et al.
are greater than in Straight Run Naphthas (Figure 14a and 14b). This is not due to higher selectivity but to the
Figure 14. Aromatic Yields in Catalytic Cracking of Naphthas and Residues
reduced during cracking reactions (Table 2). Since Naphthenes are the main components in Straight Run
evident in their sensitivity to C/O severity.
-
Figure 15. Naphthene Yields in Catalytic Cracking of Naphthas and Residues
c. Toluene and Xylenes in Residues
0
1
2
3
4
5
Toluene Xylenes Toluene Xylenes
Orthoflow Base UOPII Base
To
lu
en
ea
nd
Xyle
ne
sY
ie
ld
,%
wt
C/O= 13
C/O= 11
C/O= 10
C/O= 9
C/O= 7
C/O= 6
C/O= 5
PETROCHEMICAL PROMOTERS IN CATALYTIC CRACKING
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Due to their molecular size, Naphthenes cannot access
in Figure 15a can be attributed to additional reactions
CONCLUSIONS
-tane, and their yields are almost double the amount
Straight Run Naphthas are highly selective to-
the cases studied).
-crease in Ethylene yields in Naphthas.
about one point each.
ACKNOWLEDGEMENTS
cooperation in trial development. The authors also
observations.
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MARIA-ELIZABETH GÓMEZ et al.
158
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Fuels by 100 Metre Capillary High Resolution Gas Chromatography.
Appl.Cat.
-
Appl. Catal. A: Gen.,
Appl. Catal. A: Gen.,
United States Patent, Patent number:
-tography.
the secondary reactions in catalytically cracked gasoline. Chem. Eng. J.
-
Appl. Catal. A: Gen.,
Fuel Processing Technology,
Ind. Eng. Chem. Res.,
-Ind.
Eng. Chem. Res.,
- Ind. Eng. Chem.
Res.,
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