BOILING POINT DISTRIBUTION OF HYDROCARBONS AND SULFUR OR NITROGEN OF
MEDIUM AND HEAVY PETROLEUM DISTILLATES BY GC AND CHEMILUMINESCENCE
V. Otten1, E.B. Barendregt2 and R. Suijker2 – 1 PAC LP, 8824 Fallbrook Drive, Houston TX 77064 – 2 PAC LP, Innsbruckweg 35, 3047 AG, Rotterdam, The Netherlands
EXPERIMENTAL CONDITIONS
BP Distribution table - Percent
Recovered BP Recovered BP Recovered BP Recovered BP
mass%
°C
mass%
°C
mass%
°C
mass%
°C
FBP 396.2
70.0 298.4
30.0
222.4
IBP
74.2
80.0 315.8
40.0
249.8
5.0 144.1
90.0 341.3
50.0
265.7
10.0
164.2
95.0 357.9
60.0
281.3
20.0
192.4
FID1 A, Front Signal (TEST_081022\004F0201.D)
pA
INTRODUCTION
Chromatographic condition match ASTM D2887 and ISO3924
8000
Inlet
Petroleum products specifications are continuously tightened
regarding the concentration of heteroatom species. The stringent
requirements derive not only from environmental regulations but
also from the standpoint that these species have detrimental
effects in catalytic hydrocracking and hydrotreating processes.
Sulfur and Nitrogen are the most abundant constituents in fuels
and process streams.
Therefore, to optimize the refining
operations, it is of primary concern to determine precisely where in
the boiling range span of the processing streams these undesired
species are present.
Temperature Programmed Inlet
100°C to 350°C at 20°C/min
Column
10 m, 0.53 mm ID, 2.65 µm nonpolar
25 ml/min He carrier
Oven
35°C to 350°C at 20°C/min
Detector
Split FID – NCD / SCD
FID 370°C
40 ml/min H2, 450 ml/min Air
Gas Chromatography Simulated Distillation equipped with specific
chemiluminescence detectors for Sulfur and Nitrogen, offers the
possibility to quantify the species and additionally provide insight in
what fractions to turn more attention in order to more efficiently
meet the quality specifications. The systems simultaneously
produces three channels of data: The hydrocarbon boiling point
distribution, the Sulfur trace and the Nitrogen trace Simdis
distributions.
NCD/SCD Antek 7090N/S Dual Furnace
Sulfur Furnace: 950°C
10 ml/min O2, 90 ml/min H2,
80 ml/min He make-up
Nitrogen Furnace: 950°C
10 ml/min O2
6000
Sulphur Report
4000
Total Sulphur= 325.13 ppm S
2000
Hydrocarbon
0
0
2
4
AIB2 B, Back Signal (TEST_081022\004F0201.D)
6
8
10
12
A series of modifications have been introduced to our GC-FID
coupled with a 7090N/S chemiluminescence detector to improve
the quality of the data in terms of sensitivity and long term stability
on C5 – C70 range samples.
15 µV
800
600
400
327 ppm S
200
Sulfur
0
0
2
4
AIB3 D, 4th Signal (TEST_081022\004F0201.D)
6
8
10
12
min
• Optimized dimensions for the ceramic tubes
BP Recovered Fraction
°C
ppm S ppm S
410 313.46
4.89
420 316.54
3.08
430 318.53
1.99
440 319.90
1.37
450 320.92
1.03
460 321.69
0.77
470 322.29
0.60
480 322.81
0.52
490 323.26
0.45
500 323.67
0.41
510 324.03
0.36
520 324.36
0.33
530 324.68
0.32
540 324.98
0.29
BP Recovered Fraction
°C
ppm N ppm N
250
12.41
1.70
260
15.50
3.09
270
18.90
3.41
280
22.69
3.79
290
26.21
3.51
300
29.59
3.38
310
33.21
3.62
320
40.20
6.99
330
56.03
15.83
BP Recovered Fraction
°C
ppm N ppm N
340
74.47
18.44
350 111.08
36.61
360 143.41
32.33
370 166.77
23.36
380 180.57
13.80
390 187.81
7.24
400 192.28
4.47
410 195.77
3.49
Nitrogen Report
Total Nitrogen= 196.16 ppm N
600
• Dual furnace design for Nitrogen and Sulfur detection
BP Recovered Fraction
°C
ppm S ppm S
260
50.12
8.07
270
58.73
8.61
280
66.55
7.82
290
73.78
7.23
300
82.20
8.41
310
94.41
12.21
320 118.20
23.79
330 138.78
20.58
340 181.19
42.41
350 213.88
32.69
360 248.15
34.27
370 272.04
23.89
380 289.57
17.53
390 300.74
11.18
400 308.57
7.83
15 µV
0.1 µL neat
Modifications to the Antek 7090N/S detector are
made for higher sensitivity and robustness:
BP Recovered Fraction
°C
ppm S ppm S
110
0.22
0.22
120
0.74
0.52
130
0.93
0.20
140
1.62
0.68
150
2.72
1.10
160
3.60
0.88
170
5.06
1.45
180
6.48
1.42
190 11.54
5.06
200 14.58
3.04
210 16.92
2.34
220 25.51
8.59
230 31.24
5.73
240 34.69
3.45
250 42.05
7.36
min
800
Sample
Injection
Sulphur - cut points
400
Nitrogen - cut points
199 ppm N
200
BP Recovered Fraction
°C
ppm N ppm N
160
0.20
0.20
170
0.76
0.56
180
1.26
0.50
190
2.71
1.46
200
3.70
0.98
210
5.42
1.72
220
6.51
1.10
230
8.42
1.91
240
10.71
2.29
Nitrogen
0
0
2
4
6
8
10
12
min
Example of a Diesel Sample - A single analysis run yield three Chromatograms
• Implementation of a high capacity ozone cell
PAC Multi-elemental Simdis Software is used for boiling
point distribution and total Nitrogen/Sulfur reporting
PAC Multi-Elemental Simdis Report: Diesel Sample
DISCUSSION
EXPERIMENTAL DATA
Sulfur BP Distribution - Normalized
Nitrogen BP Distribution - Normalized
100
100
90
90
80
80
70
70
60
60
10/22/2008 05:50
10/22/2008 06:12
10/22/2008 06:35
10/22/2008 06:57
10/22/2008 07:19
10/22/2008 07:41
10/22/2008 08:03
R eco vered %
Reco vered %
10/22/2008 08:26
50
40
10/22/2008 08:48
10/22/2008 09:10
50
10/22/2008 09:32
10/22/2008 09:54
40
30
30
20
20
10
10
0
0
10/22/2008 10:16
10/22/2008 10:38
10/22/2008 11:00
10/22/2008 11:22
10/22/2008 11:45
10/22/2008 12:07
10/22/2008 12:29
0
100
200
BP °C
300
400
Hydrocarbon BP (°C) Distribution table - Percent
n = 20
IBP
10
20
Average
74.15
164.20
192.50
Stdev
0.235
0.251
0.000
0.32%
0.15%
0.00%
RSD
Sulfur
n = 20
Average
Stdev
RSD
BP (°C) Distribution table - Percent
Nitrogen
n = 20
Average
Stdev
RSD
BP (°C) Distribution table - Percent
IBP
139.87
0.905
0.65%
IBP
172.84
5.868
3.39%
10
233.39
2.083
0.89%
10
268.95
3.596
1.34%
20
277.66
1.510
0.54%
20
315.83
2.380
0.75%
30
222.50
0.000
0.00%
10/22/2008 12:51
0
500
40
250.00
0.000
0.00%
50
265.80
0.251
0.09%
100
60
281.50
0.000
0.00%
200 BP °C 300
70
298.50
0.000
0.00%
80
316.00
0.000
0.00%
400
90
341.50
0.000
0.00%
500
FBP
396.83
0.294
0.07%
99.5
30
40
50
60
70
80
90
FBP
312.72
1.290
0.41%
325.65
0.824
0.25%
335.49
0.188
0.06%
345.02
0.267
0.08%
353.58
0.400
0.11%
364.72
0.841
0.23%
382.69
1.575
0.41%
494.07
7.045
1.43%
30
40
50
60
70
80
90
FBP
99.5
330.57
0.640
0.19%
340.90
0.368
0.11%
345.94
0.242
0.07%
352.04
0.189
0.05%
358.06
0.084
0.02%
365.03
0.059
0.02%
376.53
0.253
0.07%
408.54
0.141
0.03%
Reported
Total Sulphur
327.22
3.426
1.05%
Reported
Total Nitrogen
The described multi-elemental SIMDIS system was calibrated with boiling points of normal
paraffin up to C44 (545°C). Experimental conditions listed correspond to international
standard Simdis methods such as ASTM D2887, ISO3927 and IP407.
The response for Sulfur and Nitrogen components were determined with 5 ppm Sulfur and
Nitrogen components and validated with certified NIST reference materials. Sulfur and
Nitrogen linearity and equimolarity tests performed on this system show excellent
performance.
The sensitivity of the SCD/NCD allows the analyzer to detect Sulfur concentrations below
20 ppmS and Nitrogen below 60 ppmN in diesel samples, and possibly lower depending
on the distribution of the sulfur/nitrogen components in the sample. This is based on the
mentioned 0.1 ul neat injection. Injecting larger volumes risk column overload, causing the
Boiling Point results to shift.
The system was tested to determine possible sample discrimination of either FID or
chemiluminescence detectors by splitting the column effluent.
The fact that the boiling point calibration meets all standard method requirements
concerning peak symmetry and resolution and the fact that the Reference Gas Oil
produced a boiling point distribution within the ASTM consensus values prove that the
sample analysis has not been affected and that the experimental conditions of the
standards methods were maintained.
The simultaneous system was tested for stability and robustness on diesel and gasoil
samples performing continuous unattended analyses. The experimental data shows
excellent repeatability and stability for all three boiling point distribution curves, as well
as for the Total recovered Nitrogen and Sulfur. All analysis results are based upon the
same calibration run.
Other studies indicated this methodology can be applied to D7213 (Extended) and D6352
(HighTemp) too. However, more experimental data needs to be generated to validate
system performance on these standard methods.
CONCLUSIONS
• By simultaneously utilizing the FID and the chemiluminescence
detectors while splitting the column effluent in a controlled way, in
addition to the hydrocarbon distribution, the boiling range distribution
of Sulfur and Nitrogen compounds can also be determined from a
single run.
As a result, a physical and more detailed chemical
composition characterization can be performed in a simple and rapid
manner.
• Improvements made to the Antek 7090N/S detector result in
demonstrated improved sensitivity and excellent selectivity, along
with improved robustness of the entire system.
• Experimental results on medium distillates and fractions
comprising gasoils and diesel show the boiling point distribution
and yields. The methodology is fully compliant with the ASTM
D2887 / ISO3924 / IP407 SIMDIS standard methods and produces
equivalent results for the Hydrocarbon distribution.
• The developed analytical system is fast, repeatable, and
robust and can serve as an excellent screening technique to
study refining and upgrading processes with high level of
confidence and automation.
199.47
5.377
2.70%
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