characterization of hydrocarbons in petroleum … · characterization of hydrocarbons in petroleum...
TRANSCRIPT
Characterization of Hydrocarbons in petroleum fractions using Comprehensive
Gas-Chromatography GCxGC coupledwith Fast Scan Quadrupole MSD
Marc Gibert - Ingenieria Anal´ñitica s.L.
Why GCxGC-MSD in petrochemistry
Which information is in this picture
• Fingerprint of crude oils (based on bidimensional distribution of more than1000 compounds)
Light crude oil A
Light crude oil C
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Light crude oil GC-MS chromatograms comparison
Which information is in this picture
• Fingerprint of crude oils (based on bidimensional distribution of more than1000 compounds)
• Chemical information (chemical structure, volatility, polarity, etc.)
Volatility vs. PolarityNr name RT1; RT2 (min) b.p.°C polarity index1 n-hexane 10.436; 0.715 69.0 0.12 benzene 12.536; 1.277 80.1 2.73 cyclohexane 12.536; 0.766 80.7 0.24 n-heptane 14.036; 0.817 98.4 0.05 cyclohexane, methyl 15.386; 0.868 101.0 n.d.6 toluene 18.086; 1.635 111.0 2.4
13
2 4 56
Volatility
Pola
rity
Which information is in this picture
• Fingerprint of crude oils (based on bidimensional distribution of more than1000 compounds)
• Chemical information (chemical structure, volatility, polarity, etc.)
• Information for application purposes(compound identification for geologicalexploration and process refinery uses)
• Goal: use the potentiality of the GCxGC to obtain as much as possible information and semplify instrument use for routine analysis
• One GCxGC method is here described:– to optimise the separation among classes;– to discrimine among information the more
interesting ones:–Hydrocarbons group type–S-containing compounds–N-containing compounds
GC x GC method approach
Hydrocarbons in light crude oil A
CH3
Single-ring aromatics
C30C28
C26C10 C20C6HC Saturated and Insaturated
Three ring-aromatics
(CH3)2
(CH3)3 (CH3)4 (CH3)5
CH3
CH3
(CH3)2 (CH3)3
CH3
CH3
(CH3)2
Double ring-aromatics
CH3
Single-ring aromatics
GCxGC analysis of light petroleum distillate
HC Saturated and Insaturated
Single-ring aromatics
Double ring-aromatics
Three ring-aromatics
• The increasing concern on the environmental conditions requires to limit the sulphur level in diesel fuel and gasoline (e.g. the specification in Europe for S content is lower than 10 ppm S).
• Very deep conversion of sulphur compounds is therefore required to produce extremely clean transportation fuel. Nature and amount of the sulphur compounds strongly influence the conditions of desulphurisation treatments.
• The understanding and mapping of these species is of vital importance for the further treatment of oil and oil derivatives.
Why to study sulphur compounds
S-containing compounds in light crude oil A
Thioles and sulfides in light crude oil A
1
1 – dimethyldisulfide2 – ethyl-methylethyldisulfide3 – 2-pentanthiol4 – 1-pentanthiol5 – 4-methyl, 2-pentanthiol6 – methyl ethyl disulfide7 – hexanethiol8 – tetrahydro thiopyran9 – hexanethiol10 – diethyl disulfide11 – methyl propyl disulfide12 – cyclohexanethiol13 – heptanethiol14 – dimethyl trisulfide15 – methyl cyclohexanthiol
2
3
6
4
5
7
8
9
1011
12
13
14
15
S-compounds in light crude oil A
Benzothiophenes in light crude oil A
1
2
3
4
5 6
S
S
CH3S
(CH3)2
S
(CH3)3
S
(CH3)4
1 – benzothiophene
2 – benzothiophene,2,3-dihydro
3 – benzothiophene, methyl
4 – benzothiophene, 2M5 – benzothiophene, 3M
6 – benzothiophene, 4M
CH3
(CH3)2
(CH3)3 (CH3)4
S
S-compounds in light crude oil A
Dibenzothiophenes in light crude oil A
1
23
4
CH3 (CH3)2
(CH3)3
1 – dibenzothiophene
2 – dibenzothiophene, methyl
3 – dibenzothiophene, 2M
4 - dibenzothiophene, 3M
S
S (CH3)2
S (CH3)3S CH3
64 identified compounds
S-compounds in light crude oil C
Thiophenes in light crude oil C
1 2
3
45
6
7
8
9
1011 12
13
1415 16
17 18 19
0 - thiophene1 – methyl-thiophene2 – tetrahydro-thiophene3 – dimethyl-thiophene4 – methyl-tetrahydrothiophene5 – dimethyl-thiophane6 – dimethyl-thiophene7 – tetra-hydro-thiopirane8 – dimethyl-tetrahydrothiophene9 – dimethyl-thiophene10 – dimethyl-thiophane11 – cis-2,3-dimethyl-thiophane 12 – trans-2,3-dimethyl-thiophane13 – dimethyl-thiophene14 – methyl-tetrahydrothiopirane15 – dimethyl-tetrahydrothiophene16 – dimethyl-thiophane17 – ethyl-tetrahydrothiophene18 – ethyl-methyl-thiophane19 – trimethyl-thiophene
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3D-VIEW
Benzene
3D-view: Thiophenes in light crude oil C
S CH3
S
S (CH3)2S
S CH3
S (CH3)2
thiophene
thiophene,methyl
tetrahydrothiophene
Tetrahydrotiophene,methyl
thiophene,dimethylthiophene,ethyl
thiophene,propyl
Thiophene,trimethyl
benzothiophene
Benzothiophene,2,3-dihydro
Benzothiophene,2,3-dihydro,3methyl
benzothiophene,methyl
benzothiophene,ethyl
Benzothiophene,dimethyl
Benzothiophene,dimethyl
benzenthiol
Thiophene,diethyl
Thiophene, methyl-ethyl
Thiophene, buthyl
Thiophene,diethyl
GCxGC S-compound map oflight petroleum distillate (527 ppm S )
36 identified S-compounds
Benzothiophenes 3D-view
Benzothiophene,dimethy
benzothiophene,methyl
benzothiophene,2,3-dihydro
benzothiophene
naphthalene
Naphthalene,methyl
Naphthalene,dimethyl
S
S
S
CH3
S
(CH3)2
S-compound identification: comparison with GC-AEDdata
36 S-compounds peaks
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GC-MS analysis
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Benzothiophene
Benzothiophene NIST MS spectrum
134 m/z 134 m/z
89 m/z
Benzothiophene GCxGC-MS spectrum
GC-MS spectrum
Benzothiophene GC-MS
• During desulphurisation, the presence of refractory and competitive species as nitrogen compounds is highly detrimental, due to their effect as inhibitors for HDS (hydrodesulphurisation) catalysts.
• Neutral (e.g. carbazole), slightly basic (e.g. quinoline) and basic (e.g. pyridine) nitrogen compounds are present in gas oil and cracked oil stream. The need to pre-remove these species is a function of their nature, the more stringent the removal the more basic are the species.
• The mapping of the nitrogen species is of vital importance for the further treatment of oil and oil derivatives.
Why to study nitrogen compounds
N-compounds in Naphtha
N-compounds in Naphtha
A9 A10 A11 A11A8
A7A6
pyrrole
NH
NH
CH3
pyrrole, methyl
NH
(CH3)2
NH
CH2CH3
pyrrole, dimethyl
pyrrole, ethyl
NH
(CH3)3
pyrrole, trimethyl
benzenamine
benzenamine, methyl
CH3
NH2
NH2
benzenamine, dimethyl
benzenamine, methyl ethyl
NH2 (CH3)2
NH2(CH3)
CH2CH3
pyridine
pyridine, methyl
pyridine, dimethylN
NH3C
pyridine, trimethyl
N(H3C)2
N(H3C)3
pyridine, methyl ethyl
NH3C
H2CH3C
hexanenitrile heptanenitrile
N-compounds in Petroleum fraction
N-compounds in Petroleum fraction
NH
quinoline, 1,2,3,4-tetrahydro
NH
CH3methyl-quinoline, 1,2,3,4-tetrahydro
CH3
NH
1H-indole, methyl
carbazole
NH
NH
CH3Carbazole, methyl
N-compounds in Petroleum fraction
57 identified compounds
GC-MS analysis
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40 41 42 43
Rt Carbazole 42.123 minCarbazole
Carbazole MS Spectra
GC-MS spectrum
Carbazole NIST MS spectrum167 m/z
CarbazoleGCxGC-MS
spectrum139 m/z
Development of one GCxGC methodfor petrochemical analysis
GCxGC-MSD System
GC 6890 Agilent
Technologies
MSD 5973 Fast ScanAgilent Technologies
ZOEX Dual Stage Thermal Modulator
LN2 ZoexAuto-Fill Unit
GC Agilent Technologies 6890N• Injector Split/Splittless with EPC• Split 1:100, carrier Helium• Primary column: HP-5 MS (25m x 0.25mm ID,
df=0.25μm)• Secondary column: HP-WAX (0.7m x 0.1mm ID,
df=0.1μm)• Oven: 40°C x 0.5min, 1.5°C/min to 260°C, 260°C
for 40 min (run time 187 min)• Ramp Pressure: 20psi, 0.1psi/min to 25psi,
0.55psi/min to 55psi
GCxGC-MSD System
GC 6890 Agilent
Technologies
MSD 5973 Fast ScanAgilent Technologies
ZOEX Dual Stage Thermal Modulator
LN2 ZoexAuto-Fill Unit
ZOEX dual stage thermal modulator• KT-2004 Zoex Dual Stage Thermal Modulator• LN2 Zoex Auto Fill Unit• Zoex GC-Image Software• Modulator Tube: uncoated fused silica tube 2mt X
0.1mmID• Modulation period: 9 seconds• Modulation duration: 450 msec• Hot Jet Temperature: 350°C
ZOEX modulatoroperation
GCxGC-MSD System
GC 6890 Agilent
Technologies
MSD 5973 Fast Scan AgilentTechnologies
ZOEX Dual Stage Thermal Modulator
LN2 ZoexAuto-Fill Unit
MSD 5973 Fast Scan AgilentTechnologies
• In order to maximize the spectral information, full-scan mass spectra acquisition mode (EI) was used
• MSD 5973 inert with Performance Electronics for Fast Scan Capabilities (10,000 amu/sec) and improved sensitivity
• Range 45-350 amu (19.80 scan/sec)• MS Transfer line: uncoated fused silica tube
(0.8m x 0.25mm ID, temperature 280°C)
Development of one GCxGC method forpetrochemical analysis
How many variables in setting up a GCxGC method?Columns choice (stationary phase and lenght)Main oven temperature and/or secondary oven temperatureColumn flowModulation period and durationCold and Hot jet flows
Simplify the user operation maintaining fixed the conditionsfor all type of compounds in oil-derivatives
• Column combination to maximize GCxGC potentiality: the most “bi-dimensional” stationary phases must be usedPrimary column: apolarSecondary column: polar
• Separate wide variety of hydrocarbon compounds (saturate/insaturate, light up to heavy aromatics and heteroatom compounds)
• Which stationary phase and column lenght?• Wax : polyethylene glycol• DB-1701: 14% cyanopropyl-phenyl, 86% dimethylpolysiloxane• HP-17: 50% phenyl, 50% dimethylpolysiloxane
Column choice
Secondary column 1 mt x 0.1 mmID x 0.1 um DB-1701Oven: 35°Cx0min, incr. 2°C/min to 300°C for 10 minNo secondary oven
Modulation period : 6 sec.
1 meter DB-1701Naphtalene
byphenyl
Three ring aromatics
Naphtalene
Three ring aromatics
byphenyl
Modulation period : 9 sec.
1 meter HP-17byphenyl
Three ring aromatics
Naphtalene
Secondary column 1 mt x 0.1 mmID x 0.1 um HP-17Oven: 40°Cx0.5min, incr. 2°C/min to 300°C for 10 minNo secondary oven
Secondary column 2 mt x 0.1 mmID x 0.1 um WAXOven: 40°Cx0.5min, incr. 0.5°C/min to 260°C for 40 minSecondary Oven: 30°C above main oven
Naphtalene
Three ring aromatics
Wrap-around
Modulation period : 9 sec.
2 meters WAX
byphenyl
Modulation period : 9 sec.
0.7 meter WAX Three ring aromatics
Secondary column 1 mt x 0.1 mmID x 0.1 um WAXOven: 40°Cx0.5min, incr. 0.5°C/min to 260°C for 40 minSecondary Oven: 30°C above main oven
Naphtalene
byphenyl
• Large enough to permit the elution of all the components from the secondary column (y- axis, separation by polarity)
• Should be tuned to collect at least three fraction of the elutingprimary column peaks (high modulation period values require wideprimary column peaks)
Modulation period
Naphtalene
byphenyl
Three ring aromatics
9 seconds mod. period
Modulation period
Modulation period
Nr name RT1; RT2 (min) b.p.°C
1 benzene 12.536; 1.277 80.12 ciclohexane 12.536; 0.766 80.7
1
2
Modulation period
BenzeneCiclohexane 1
1 st modulation
2 nd modulation
3 rd modulation
4 th modulation
Conclusions
• The GCxGC-qMSD showed to be a powerful tool in light petroleum fraction investigation. Its use allows the separation and identification of different polarity hydrocarbons (aromatic vs aliphatic) together with unique identification of heteroatom compounds, with a single sample run and without changing any analytical set up and parameters.
Thank you for your attention