Improve refinery reformate yields

Full text

PROCESS DEVELOPMENTS
HYDROCARBON PROCESSING october 2008
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In an octane-constrained world, refiners are seeking processing
changes to raise the research octane number (RON) values of
the gasoline blending pool. Catalytic reforming provides high-
octane blending streams and aromatics streams for the petrochem-
ical industry as well as hydrogen for hydrotreating processes. In
this case history, the refiner revamps an existing catalytic reformer
to increase RON of the blending pool.
Background. The main objective of modern catalytic reform-
ing units is providing high-octane components from the gasoline
blending pool. In addition, these units yield aromatics streams for
petrochemical production as well as hydrogen for hydrotreating
units. Catalytic reformer economics are favored by a higher refor-
mate yield with a longer cycle length.
One method to increase reformate, aromatics and hydrogen
yields is to operate the reformer at lower
pressure. However, the lower pressure favors
coke formation and accelerates the catalyst
deactivation. This is a critical situation for
fixed-bed semi-regenerative reformers since
the lower pressure reduces the run length.
These disadvantages can be overcome by
revamping the existing semi-regenerative
reforming (SR) units to either a catalytic
reformer or hybrid version.1
The hybrid design maximizes usage of the
existing reactor section equipment in an SR
catalytic reformer. Typically, such a revamp
includes adding a new fluidized-bed reactor
that operates with continuous catalyst circu-
lation to the existing fixed-bed reactors.
In 2004, the Lukoil Neftochim Bulgaria
(LNB) SR reformer was converted to a
hybrid catalytic reformer. From the revamp,
unit capacity was increased by 50%, and the
reformate RON increased from 95 to 100
points.2 The first cycle of the LNB hybrid
catalytic reformer project started up in April
2004 and ended in April 2006.
Old naphtha unit. Fig. 1 is a simplified
diagram of the LNB hybrid catalytic reformer
unit. The feedstock is straight-run naphtha
(SRN) from the crude distillation units,
which typically processes Urals crude oil and
occasionally light Siberian crude oil. The SRN is hydrotreated, and
the hydrotreated SRN is sent to the catalytic reformer section.
The reformer feed properties are expressed by hydrocarbon group
composition, and ASTM D86 distillation and sulfur content during
the hybrid catalytic reformer cycle and are presented in Figs. 2 and
3. The data indicate that during the entire first cycle the reformer
feed quality was almost the same excluding sulfur content. After
the sixteenth month, the feed sulfur content exceeded the refiner’s
accepted level of 0.5 wtppm.3 Later, during a turnaround, a leak was
identified in the heat exchangers used to heat product streams.
Improvements. Data of the operating conditions—LHSV,
reactors inlet temperature and reactors ΔT, reformate RON and
reformate yield from LNB hybrid catalytic reformer—are sum-
marized in Figs. 4 and 5. During the first five months of the cycle,
Improve refinery reformate yields
This refiner installed a hybrid catalytic reforming unit to raise octane
of gasoline blending pool
G. ARGIROV, D. STRATIEV, I. SHISHKOVA and T. TSINGOV, Lukoil Neftochim Bourgas
JSC, Bourgas, Bulgaria
Product
recovery
Product
recovery
Recycled gas
turbo compressor
∆P=470 kPa
Furnace
Exchanger
Exchanger
Naphtha
H2 makeup
CCR
R-3
R-4
R-2R-1
Furnace
Furnace
Separator
Separator
Flue gas to
power recovery
section
Reformer
feed
Reformate
H2 makeup
Flow diagram of the hybrid catalytic reforming unit at the Lukoil Neftochim Bourgas
refinery.
FIG. 1
Proof only. Copyrighted material.
May not be reproduced without permission.

PROCESS DEVELOPMENTS
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october 2008 HYDROCARBON PROCESSING
TABLE 1. Detailed hydrocarbon composition of LNB hybrid catalytic reformer feed and reformate samples taken
during the first operating cycle
Months throughout 1 1 5 5 5 5 14 14 16 16 16 16 20 20 20 20 20 20
the cycle
Platforming reactors 0.95 0.64 0.65 0.91 0.92 0.93 0.96 0.96 0.8
LHSV, h-1
Feed sulfur, wtppm 0.37 0.56 0.29 0.22 0.48 1.18 0.95 0.7
FB+moving bed 496 473 477 499 501 502 504 504 499
reactor WAIT, °C
FB reactors WAIT, °C 483 463 463 480 483 483 483 483 483
RON 100 95.3 97.4 99.5 99.3 99 99.6 99.8
MON 89.2 85 87 88.1 89.2 88.8 90.6 90
Composition, wt,%
n-Paraffins
n-C2 0.131 0.003 0.001 0.015
n-C3 0.15 0.31 0.29 0.006 0.326 0.437 0.403
n-C4 1.54 1.61 1.77 1.813 2.471 1.929 2.265 2.398 2.546
n-C5 0.01 1.71 1.66 1.87 0.002 2.152 0.002 2.429 0.007 2.206 2.92 0.015 2.987 0.193 2.996
n-C6 1.05 1.57 1.55 1.68 0.729 1.535 0.493 1.561 0.855 1.782 1.832 0.525 1.802 0.464 1.773
n-C7 4.6 1.62 2.29 1.98 4.649 1.462 6.288 1.849 4.64 1.631 1.77 5.699 1.629 5.506 1.649
n-C8 6.26 0.78 1.31 1.13 7.952 0.733 8.021 0.735 8.205 0.871 0.745 8.036 0.65 7.742 0.597
n-C9 5.72 0.21 0.45 0.35 6.513 0.154 6.243 0.155 6.599 0.217 0.169 6.445 0.155 6.517 0.107
n-C10 3.37 0.21 0.19 0.2 3.337 0.209 2.737 0.153 3.154 0.037 0.027 3.091 0.124 3.447 0.132
n-C11 0.45 0.734 0.622 0.335 0.478 0.408 0.01 0.003 0.432 0.003 0.575
n-C12 0.02 0.035 0.01 0.015 0.025 0.008 0.001 0.024 0.001 0.034
n-C13 0.001 0.02 0
Total n-Paraffins 21.48 7.79 25 9.37 24.3 9.27 23.95 8.821 24.134 9.831 23.902 8.693 22.8 10.058 24.287 10.201 24.478 10.202
iso-Paraffins
i-C4 0.84 0.91 0.97 0.807 1.199 0.019 0.909 1.184 1.272 1.294
i-C5 2.64 2.69 2.97 0.001 3.242 3.592 0.006 3.06 4.086 0.005 4.235 0.136 4.298
i-C6 0.48 3.61 3.53 2.86 0.267 3.656 0.176 3.684 0.377 0.801 4.089 0.245 4.209 0.166 4.262
i-C7 3.41 5.41 7.86 6.94 3.022 5.132 3.827 6.282 3.085 5.161 5.668 3.224 5.658 3.443 5.661
i-C8 8.86 3.79 6.34 5.55 8.111 3.17 8.633 3.083 8.168 3.691 3.098 10.542 2.83 9.65 2.535
Feed
Reformate
Feed
Reformate
Feed
Reformate
Feed
Reformate
Feed
Reformate
Feed
Reformate
Feed
Reformate
Feed
Reformate
Feed
Reformate
the reformate RON was about 98 points and the reformate yield
was approximately 87 wt%. In the sixth month, the reformate
RON was 99.9 and the yield was 84.5 wt%. In addition during
the seventh month, the reformate RON was 100 and the yield
averaged 85.1 wt%. Notably, increasing the reformer RON by 1
point decreased yield by 1 wt%. Data for the first seven months
indicates that at the same reformate RON and different space
velocities (throughput), the reformate yield was higher when the
space velocity was higher. Accordingly, increased residence time
favors hydrocracking reactions over dehydrocyclization.
From the sixth month to the end of the cycle (24 months), the
reformate RON averaged 99.3 points. The reformate yield from
the sixth to the sixteenth month was 85 wt%. After the sixteenth
month of the run, there was a step decrease in reformate yield
from 85 wt% to 83 wt%. The yield remained unchanged until
the end of the cycle. Along with the reformate yield reductions,
the fixed-bed reactors’ temperature drop decreased. This trend
coincided with the higher sulfur-content reformer feed (Fig. 2.)
Sulfur issues. Obviously, the higher sulfur-content feed regis-
tered after the sixteenth month of hybrid catalytic reformer cycle and
50 2 4 6 8 10 12 14 16 18 20 22 24
20
35
50
65
80
95
110
125
140
155
170
185
200
Analyzed samples throughout the cycle
IBP, 10 vol%, FBP, °C
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
Sulfur, wtppm
IBP
10 vol%
FBP
Feed sulfur
Monthly averages of the feed distillation and sulfur
content for the hybrid catalytic during the first operation
cycle.
FIG. 2
Continued

PROCESS DEVELOPMENTS
HYDROCARBON PROCESSING october 2008
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caused deactivated fixed-bed catalyst. This deactivation was compen-
sated by higher fluid-bed reactor inlet temperature. In accordance
with the catalyst service procedure for temporary sulfur poisoning,
the inlet temperature of the first and second fixed-bed reactors was
reduced.4 As a result, the high reformate RON was maintained, but
the higher fluid-bed reactor severity reduced reformate yield.
Octane values. Table 1 summarizes the composition by group
type and number of carbons of hybrid catalytic reformer feed
and reformate sampled during the cycle. The data indicate that
to maintain a reformate RON of 99+ when processing the Urals
SRN requires 80% conversion of C7+paraffins. To maintain a
RON of 97 requires a 70% conversion rate while a RON of 95
needs a 65% conversion rate.
Until the sixteenth month of the cycle, catalyst selectivity for
aromatics was about 24%. However, the higher sulfur-content
feed dropped selectivity to 17.4%. Fig. 6 illustrates the relation
between catalytic reformer feed sulfur content and catalyst selec-
tivity to convert C7+ paraffins into aromatics.
Regardless of the heat-exchanger leak in the SRN hydrotreating
section and resulting higher feed sulfur, the hybrid catalytic reformer
was capable of producing reformate with a RON of 99+ over the
i-C9 8.14 1.14 2.46 2.69 9.315 0.591 11.373 0.585 11.715 1.037 0.753 8.47 0.549 9.217 0.431
i-C10 6.53 0.17 0.35 0.47 9.089 0.028 7.976 0.023 8.71 0.176 3.553 7.479 0.031 7.051 0.14
i-C11 3.6 1.66 0.078 1.036 0.072 1.336 0.009 2.051 0.064 2.196 0.057
i-C12 0.046 0.172 0.012 0.068 0.023 0.124 0.038 0.017 0.047 0.004
i-C13 0 0.087 0 0.005 0 0.002 0
Total I-Paraffins 31.02 17.6 31.9 24.14 33.1 22.42 31.511 16.963 33.033 18.588 33.437 17.836 33.8 22.569 32.054 18.867 31.906 18.681
Naphthenes
C5 0.02 0.21 0.19 0.21 0.005 0.058 0.004 0.074 0.012 0.089 0.115 0.013 0.108 0.005 0.091
C6 2.13 0.39 0.38 0.38 1.697 0.196 1.569 0.335 1.848 0.536 0.552 1.477 0.458 1.337 0.35
C7 7.98 0.36 0.24 0.22 8.239 0.131 10.458 0.283 8.403 0.445 0.591 8.004 0.436 7.543 0.304
C8 8.35 0.19 0.36 0.33 9.487 0.246 8.058 0.273 8.56 0.53 0.691 7.368 0.551 7.231 0.349
C9 7.46 0.07 0.32 0.2 7.003 0.083 7.635 0.005 7.761 0.022 0.106 8.882 0.201 8.177 0.024
C10 4.06 1.178 0.046 1.324 0.047 1.469 0.045 1.644 0.101 1.509 0.095
C11 0.426 0.269 0.352 0.085 0.06
C12 0.003 0.063 0 0.038 0.039 0.002 0.052 0.002 0.039
Total naphthenes 30 1.22 25.2 1.49 24.9 1.34 28.038 0.823 29.317 1.055 28.406 1.661 25.5 2.1 27.475 1.907 25.864 1.252
Aromatics
C6 0.11 2.9 1.72 2.06 0.093 2.197 0.073 1.986 0.116 1.943 2.044 0.104 2.033 0.078 2.028
C7 1.53 15.03 12.52 12.88 1.462 13.695 1.912 16.244 1.569 13.372 14.435 1.863 14.875 1.745 14.792
C8 5.7 23.5 19.96 21.35 4.199 24.443 4.433 24.186 4.477 24.255 22.683 5.266 23.501 4.656 23.733
C9 3.43 19.93 10.58 10.92 4.803 19.275 4.082 17.034 4.44 13.234 8.359 3.459 10.518 3.878 10.921
C10 2.03 8.92 16.94 16.61 2.157 9.768 1.486 7.947 2.203 14.779 14.219 1.935 15.024 1.971 14.601
C11 2.11 1.72 1.69 0.196 2.146 0.066 1.495 0.092 1.312 0.2 0.102 0.692 0.112 1.502
C12 0.084 0.378 0.019 0.373 0.045 0.252 0.495 0.054 0.503 0.072 0.285
Total aromatics 12.8 72.39 15.6 63.44 15.5 65.51 12.994 71.902 12.071 69.265 12.943 69.148 13.3 62.435 12.783 67.146 12.512 67.862
Total PIONA, wt% 100 100 100 100 100 100 100 100 100 100 100 100 100 99.336 100 100 100 100
Olefins 1.14 0.15 0.1 0 0.656 0.644 0.117 0.422 0.016 0.13 1.2 0.836 1.232 1.118 1.094 0.496
Unknowns 3.56 0.85 2.2 1.56 2.2 1.46 2.85 0.847 1.329 0.839 1.295 2.533 3.4 1.338 2.164 0.761 4.149 1.508
N
+2
A
55.6 56.4 55.9 54.026 53.459 54.292 52.1 53.041 50.888
Feed/reformate 50.96 13.33 56.9 21.25 57.4 19.28 54.463 12.448 56.496 13.483 56.066 15.841 56.6 15.925 55.551 11.713 55.425 11.311
C7+ paraffins, wt%
Paraffins 77.8 66.5 70.6 80.6 80.0 76.5 76.5 82.5 83.1
C7+ conversion, wt%
C5+ reformate 85 89.6 87.6 85 84 83.3 83.5 83 83
yield, wt%
Selectivity 24.1 24.1 24.1 24.9 21.0 21.3 17.4 18.8 21.6
0 2 4 6 8 10 12 14 16 18 20 22 24
Analyzed samples throughout the cycle
5
10
15
20
25
30
35
40
45
50
55
60
65
70
PNA, wt%
47
48
49
50
51
52
53
54
55
56
57
58
59
60
N+2A
Paraffins
Naphthenes
Aromatics
N+2A
Monthly averages of the paraffins, olefins, naphthenes and
aromatics (PONA) content for the hybrid catalytic during
the first operation cycle.
FIG. 3
Continued

PROCESS DEVELOPMENTS
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october 2008 HYDROCARBON PROCESSING
first cycle length, which was 24 months. This condition was possible
since the first two fixed-bed reactors were loaded with a balanced
platinum (Pt)—rhenium (Re) reforming catalyst. This promoted
reforming catalyst is known to have a high tolerance to short-term
operational upsets, such as water or sulfur excursions.5
Reactor temperatures. Before the revamp of the semiregen-
erative LNB catalytic reformer to the hybrid design, the maximum
reformate RON was 95 and the maximum reformate yield was
84 wt% over an 11-month cycle. The ability to continuously
maintain the high-severity operating mode in the fluid-bed reactor
allowed reducing the fixed-bed reactor inlet temperature. At the
end of the hybrid cycle, the fixed-bed reactors weight average inlet
temperature was in the range of 482°C–486°C. This temperature
is approximately 20°C lower than the end-cycle temperature for
the SR reforming unit. Under these conditions, the cycle length
of the hybrid catalytic reformer could be longer than 24 months.
However, due to higher feed sulfur content and the resulting
lower dehydrocyclization catalyst selectivity and consequent lower
reformate yield, the first LNB hybrid catalytic reformer cycle was
limited to 24 months.
89.0
88.0
89.1
88.5
88.6
87.5
85.8
86.4
87.0
86.8
86.2
86.9
86.3
86.1
86.0
86.3
86.0
85.3
84.2
84.2
83.8
84.1
84.6
83.8
84.1
0 2 4 6 8 10 12 14 16 18 20 22 24
First cycle monthly average data on stream
35
40
45
50
55
60
65
70
75
80
85
90
95
Reformate yield, wt%
0
10
20
30
40
50
60
70
80
90
100
110
120
Reactor ∆T, °C
Reformate yield
FB R1 ∆T
FB R2 ∆T
FB R3 ∆T
Moving-bed reactor ∆T
Monthly averages of the 
T
and reformate yield for the
hybrid catalytic during the first operation cycle.
FIG. 4
TABLE 2. Detailed hydrocarbon composition of the model reformate samples, LSRN, aromatics cut and original
reformate samples
Hydrocarbon Aromatics Light
composition, wt% Model reformate samples cut SRN Original reformate samples
1 2 3 4 5 6 1 2 3 4 5
n-Paraffins
C3 0.4 0.26 0.25
C4 1.90 1.71 1.52 1.33 1.14 0.76 3.79 2.80 1.95 2.40 2.66 2.40
C5 6.86 6.17 5.49 4.80 4.12 2.74 13.72 3.60 2.45 3.30 3.36 2.93
C6 5.80 5.22 4.64 4.06 3.48 2.32 11.60 2.00 1.95 2.30 2.19 1.75
C7 3.43 3.09 2.74 2.40 2.06 1.37 6.86 1.50 1.53 1.80 1.93 1.61
C8 0.51 0.45 0.40 0.35 0.30 0.20 1.01 0.60 0.71 0.80 0.81 0.65
C9 0.20 0.20 0.30 0.18 0.13
C10 0.08 0.08 0.09 0.10 0.11 0.12 0.15 0.15 0.11 0.1
Total n-Paraffins 18.57 16.72 14.88 13.04 11.20 7.52 0.15 36.98 10.70 9.34 10.90 11.50 9.82
iso-Paraffins
C4 0.30 0.27 0.24 0.21 0.18 0.12 0.60 1.50 1.07 1.60 1.39 1.23
C5 4.58 4.12 3.66 3.21 2.75 1.83 9.16 5.00 3.54 4.50 4.82 4.25
C6 6.84 6.15 5.47 4.78 4.10 2.73 13.67 4.50 4.27 4.80 4.94 4.14
C7 4.72 4.24 3.77 3.30 2.83 1.89 9.43 5.10 5.03 5.60 6.71 5.85
C8 2.26 2.03 1.81 1.58 1.36 0.90 4.52 2.50 3.58 3.40 3.91 3.12
C9 0.07 0.06 0.05 0.05 0.04 0.03 0.13 0.40 0.99 0.10 0.96 0.59
C10 0.15 0.05 0.09
Total iso-Paraffins 18.76 16.88 15.00 13.13 11.25 7.50 37.51 19.00 18.63 20.00 22.78 19.27
Naphthenes
C5 0.68 0.61 0.54 0.47 0.41 0.27 1.35 0.26 0.32 0.26
96 97.3 98.2 97.6 98.2 99.9 10099.1 99.2 99.9 99.3 98.8 99.3 99.7 99.5 99.1
99.1 99.4
99.4 99.6 99.199.2 99.3
98.9
98.2
460
468
476
484
492
500
508
516
524
532
RIT, °C
53
59
65
71
77
83
89
95
101
107
RON, MON, LHSVx100, h-1
FB R1IT
FB R2IT
FB R3IT
Fluid-bed RIT
LHSV
RON
MON
0 2 4 6 8 10 12 14 16 18 20 22 24
First cycle monthly average data on stream
Monthly averages of the reactor inlet temperature,
space velocity and reformate octane value for the hybrid
catalytic during the first operation cycle.
FIG. 5
Continued

PROCESS DEVELOPMENTS
HYDROCARBON PROCESSING october 2008
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Catalyst evaluation. The analysis of catalyst activity and
selectivity in a reformer was done on the base unit yield distri-
bution and reformate hydrocarbon composition by group type
and number of carbons. A gas chromatograph (GC) was used to
determine catalyst activity and selectivity. This method is not suit-
able for daily monitoring of reformate hydrocarbon composition.
The LNB research laboratory study was performed to develop
correlations between reformate hydrocarbon composition and
physical and chemical properties obtained by routine refinery
daily analyses.
Composition evaluations. To evaluate the reformate hydro-
carbon composition by group type and number of carbons, five
model reformate samples were prepared by blending light straight-
run naphtha (LSRN: fraction 40°C–100°C) with a toluene frac-
tion, xylene fraction and C9+ fraction from the reformate in ratios
similar to those in the original reformate. Table 2 summarizes the
results for the detailed hydrocarbon composition by group type
and number of carbons for the model reformate samples, original
reformate samples and base LSRN and mixed aromatic fraction
(C7 –25 wt%; C8 –35 wt%; C9+ –40 wt%). The physical and
chemical properties and calculated properties based on paraffinic
(P), aromatic (A) and naphthenic (N) portions by the correlations
of Riazi and Daubert are summarized in Table 3.6 The correlations
of Riazi and Daubert used in the presented work are:
P% = 257–287.7S+2.876CH (1)
N% = 52.641–0.7494(P%)–2.1811m (2)
A% = 100–(P%+N%) (3)
where
S = Specific gravity at 60/60°F (15.6/15.6°C)
m = MW(n–1.4750)
n = Refraction index at 20°C
MW = Molecular weight – calculated by the Goosens
correlation:7
MW = 0.01077.(TBP)[1.52869+0.06486.ln(Tb/(1078–Tb))]/d, (4)
d = Liquid density at 20/4°C, d420;
Tb = 50% boiling point of the ASTM D-86 distillation + 4.5,
K
CH = Carbon/hydrogen ratio, estimated as (100–H)/—the
level of the remaining components sulfur and nitrogen is almost
zero in the reformate.
The hydrogen content (H) was calculated by the Goosens
correlation:8
H = 30.346–65.341n/d+82.952/d– 306/MW (5)
C6 2.81 2.52 2.24 1.96 1.68 1.12 5.61 0.30 0.43 0.30 0.66 0.36
C7 6.26 5.63 5.01 4.38 3.76 2.50 12.52 0.70 0.49 1.20 0.34 0.20
C8 1.99 1.79 1.59 1.39 1.19 0.80 3.98 0.20 0.29 0.40 0.23 0.13
C9 0.25
C10
Total Naphthenes 11.73 10.56 9.38 8.21 7.04 4.69 23.46 1.20 1.72 1.90 1.55 0.95
Aromatics
C6 0.45 0.40 0.36 0.31 0.27 0.18 0.89 2.50 2.76 2.30 2.44 2.42
C7 13.63 14.91 16.19 17.48 18.76 21.33 26.46 0.79 16.00 13.99 14.50 14.37 15.16
C8 17.89 19.67 21.44 23.22 24.99 28.54 35.64 0.14 25.00 22.85 23.70 22.40 25.05
C9 12.74 14.01 15.29 16.56 17.84 20.38 25.48 24.90 19.12 25.20 13.98 15.74
C10 5.12 5.63 6.14 6.65 7.16 8.18 10.23 8.72 9.55 10.49
C11 0.74 0.81 0.88 0.96 1.03 1.18 1.47 1.68 0.50 0.54
C12 0.06 0.06
Total Aromatics 50.55 55.42 60.30 65.17 70.04 79.79 99.28 1.82 68.40 69.12 65.70 63.30 69.46
Olefins
C4 0.01 0.01 0.01 0.01 0.01 0.02 0.02 0.05 0.02 0.04 0.02
C5 0.02 0.02 0.02 0.01 0.01 0.01 0.04 0.06 0.19 0.07 0.13 0.11
C6 0.01 0.01 0.10 0.10 0.02 0.02
C7
C8 0.08 0.07 0.06 0.05 0.06 0.02 0.15 0.01
Total olefins 0.11 0.10 0.09 0.07 0.08 0.03 0.22 0.18 0.25 0.19 0.19 0.15
Unknown 0.29 0.32 0.35 0.38 0.39 0.47 0.57 0.01 0.52 0.94 1.31 0.68 0.35
Total 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00
0
5
10
15
20
25
30
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
Feed sulfur, wt%
Selectivity, %
Catalysts dehydrocyclization selectivity vs. hybrid catalytic
reformer feed sulfur levels.
FIG. 6
Continued

PROCESS DEVELOPMENTS
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october 2008 HYDROCARBON PROCESSING
By regression of Table 3 data, a correlation was developed that
predicts the reformate aromatics content from its density, D-86
distillation, refraction and estimated parameters paraffinic, aro-
matic and naphthenic portions, hydrogen content and carbon/
hydrogen ratio. This correlation is:
Aromatics, % = –17.7248 N + 22.18757 A + 8.830196 CH +
127.9028 H – 1878.18 (6)
Fig. 7 illustrates the correspondence between calculated by
Eq. 6 and measured by GC aromatics content in the reformate.
The data indicate that Eq. 6 satisfactorily predicts the reformate
aromatics content and can be used for daily monitoring of the
reformate composition.
The reformate relationship between RON and motor octane
number (MON) and aromatics content is depicted in Fig. 8. From
this investigation, octane is linearly dependent on the reformate
aromatics content. While the RON values of the model and
original reformate samples center on a line, the original refor-
mate sample MONs were 1 point higher than those values of
the model reformate samples. This difference in the MON can
be explained by the higher isoparaffins content in the original
reformate samples. The isoparaffins are known to have higher
blending MON than RON.9
Overview. Processing of SR-naphtha from Urals crude oil that
has characteristic index of 2A+N of 55 in the hybrid catalytic
40
45
50
55
60
65
70
75
80
85
90
95
100
40 50 60 70 80 90 1005545 65 75 85 95
Aromatics calculated, wt.%
Aromatics measured, wt.%
Reformate aromatics content—measured by GC vs.
calculated in wt%.
FIG. 7
80
82
84
86
88
90
92
94
96
98
100
102
104
106
108
110
Reformates aromatics content, wt%
RON and MON
RON model reformates
RON original reformates
MON model reformates
MON original reformates
44 48 52 56 6050 54 58 62 68 7246 66 747064
RON and MON values vs. reformate aromatics content.
FIG. 8
TABLE 3. Physical and chemical properties of the model reformate samples, LSRN, aromatics cut and original
reformate samples
Hydrocarbon Aromatics Light
composition, wt% Model reformate samples cut SRN Original reformate samples
1 2 3 4 5 6 1 2 3 4 5
Density at 20°C, g/cm3 0.776 0.786 0.795 0.806 0.816 0.832 0.871 0.683 0.794 0.796 0.790 0.790 0.792
nd20 1.4599 1.4621 1.4672 1.4714 1.4772 1.4873 1.5045 1.3890 1.4689 1.4696 1.4656 1.4678 1.4720
Distillation ASTM D86, °C
IBP 41 44 42 48 48 53 121 39 36 36 36 37 39
5 vol% 56 62 62 68 69 83 126 53 52 58 50 53 55
10 vol% 65 70 71 78 80 97 128 56 67 71 55 68 69
20 vol% 78 84 86 96 100 114 131 60 90 95 87 90 93
30 vol% 90 97 101 111 114 123 135 63 109 111 106 108 111
40 vol% 102 110 114 121 124 130 138 68 122 122 119 120 122
50 vol% 114 122 124 130 133 135 143 71 131 131 129 130 131
60 vol% 126 132 133 138 139 141 148 75 139 140 138 139 139
70 vol% 137 142 142 146 147 148 153 79 148 148 146 148 149
80 vol% 149 152 152 155 156 157 160 84 156 158 155 156 158
90 vol% 164 167 166 170 170 170 171 91 169 173 169 172 171
95 vol% 180 185 179 186 185 188 180 96 187 193 188 192 193
FBP 199 199 200 202 207 209 221 97 206 210 201 202 203
Estimated parameters
A,% 30.1 31.3 33.0 34.7 36.6 39.8 46.2 33.2 33.5 32.2 32.7 33.7
P,% 55.4 52.2 50.2 47.2 44.9 41.6 31.9 50.8 50.0 51.4 51.8 51.7
N,% 14.5 16.5 16.8 18.1 18.5 18.6 21.9 16.1 16.4 16.4 15.5 14.6
C/H 7.816 7.732 7.920 7.974 8.184 8.626 9.152 7.969 7.979 7.825 7.959 8.195

PROCESS DEVELOPMENTS
HYDROCARBON PROCESSING october 2008
I
7
reforming unit allowed LNB to produce reformate with a RON
of 99+ for 24 months. The higher RON value corresponds to
about 1% reduction of the reformate yield. Obtaining refor-
mate with the same RON at different throughput showed that
reduced reformate yield occurred at reduced space velocity. An
increase in feed sulfur content above processing limits of 0.5
ppm can decrease catalyst selectivity to dehydrocyclization. The
increase of feed sulfur by 0.1 ppm also decreased catalyst selectiv-
ity to dehydrocyclization by 0.7%. The reformate octane linearly
depends on its aromatics content. A correlation was developed
that allows predicting aromatics content in the reformate from
laboratory data of reformate density, distillation ASTM D-86
and refraction. HP
LITERATURE CITED
1 Domergue, B., P. Y. Le Goff, and J. Ross, “Octanizing reformer options,”
Petroleum Technology Quarterly, Winter 2006, p. 72.
2 Argirov, G., et al., “Lukoil Neftochim Bourgas Naphtha Semiregenerative
Reformer Revamping to Hybrid Platforming Unit,” Proc.42 IPC, Bratislava,
September 2005.
3 Le Goff, P.-Y., F. Le Peltier, B. Domergue, and J. F. Joly, “Catalytic solutions
for improved performance,” Petroleum Technology Quarterly, Spring 2003, p.
28.
4 Procatalyse and Institut Français du Petrole Catalysts, RG series Catalyst
Handbook, Rev. E, April 1998.
5 Bonneville, J.-de and J. L. Nocca, “Fixed-bed reformer revamps for gasoline
improvement,” Petroleum Technology Quarterly, Summer 2000, p. 80.
6 Riazi, M. R., and T.E. Daubert, “Prediction of Molecular-Type Analysis of
Petroleum Fractions and Coal Liquids”, Ind. Eng. Chem. Process. Dev., Vol.
25, pp. 1,009–1,015, 1986.
7 Goosens A. G. “Prediction of molecular weight of petroleum fractions,” Ind.
Eng. Chem. Res., Vol. 35, No. 3, p. 985, 1996.
8 Goosens, A., “Prediction of the hydrogen content of petroleum fractions,”
Ind. Eng. Chem. Res., Vol. 36, p. 2,500, 1997.
9 American Petroleum Institute Research Project 45, 1957.
Georgi Argirov is a research associate in the catalysis section
of the Lukoil Neftochim Bourgas R&D Department. He joined Lukoil
Neftochim Bourgas in 2001 as an operator in the absorption gas
fractionating unit. After this position, he joined the catalysis labora-
tory at the Research Institute for Oil Refining and Petrochemistry as
a process engineer. Mr. Argirov holds an MS degree in inorganic chemistry engineer-
ing from the Univeristy of Bourgas.
Dicho Stratiev is an associate professor, PhD and research
department manager in the Lukoil Neftochim Bourgas, Bulgaria.
He has authored more than 60 papers. Dr. Stratiev has held several
positions in the research and production activities during his 17
years career with the Lukoil Neftochim Bourgas.
Ivelina Shishkova is a resea rch associate for the Lukoil
Neftochim Bourgas R&D Department. She joined Lukoil Neftochim
Bourgas in 2002 as a process engineer in the catalysis laboratory in
the Research Institute for Oil Refining and Petrochemistry. In 2003,
she was appointed as a research associate in the catalysis labora-
tory. Ms. Shishkova holds an MS degree in organic chemistry engineering from the
Univeristy of Bourgas.
Todor Tzingov is a research associate in the catalysis section of
the Lukoil Neftochim Bourgas R&D Department. He joined Lukoil
Neftochim Bourgas, Bulgaria in 1977 as a shift supervisor in the
normal paraffins unit. In 1981, he was appointed as a research
associate in the catalysis laboratory in the Research Institute for
Oil Refining and Petrochemistry in Lukoil Neftochim. In 2004, he was appointed as
a head of the catalysis section of the Lukoil Neftochim Bourgas R&D Department.
He holds an MS degree in chemical engineering with a focus in oil refining from the
Univeristy of Bourgas.