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HYDROCARBON PROCESSINGDESULPHURISATION
AND
DIESEL QUALITY IMPROVEMENT
English version based on the presentation of
Prof. Dr. Jenő Hancsók, D.Sc.
held on 08.10.2014
Pannon UniversityMOL Crude Oil and Coal Technology Department
MOL Ásványolaj- és
Széntechnológiai Intézeti
Tanszék
Vegyészmérnöki- és
Folyamatmérnöki Intézet
8200 Veszprém, Egyetem u. 10. Pf. 158.
Tel.: +36 88/624217 Fax.:+36 88/624520
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright 2
Crude oil distillation fractions: carbon number
and atmospheric boiling point range
2
Desulphurisation of
hydrocarbon fractions
44
Desulphurisation of hydrocarbon fractions
Necessity, importance
◼ To meet product quality specifications (10 ppm)
◼ To prevent catalyst poisoning during later
processing (CCR, LNI)
◼ To prevent corrosion
◼ To protect car exhaust gas catalyst
◼ General and specific environment protection
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
55
LPG Desulphurisation
Sulphur compounds in LPG
◼ carbonyl-sulphide (COS; bp.: -50°C)
◼ methyl-mercaptan (CH3SH; bp.: +6°C)
Processes
◼ Removal with caustic
Mercaptan-reformulation:
RSH + NaOH → RSNa + H2O
H2S + 2 NaOH → Na2S + 2 H2O
Caustic regeneration:
2 RSNa + ½ O2 + 2 H2O → RSSR + 2 NaOH + H2O
2 Na2S + 4 H2O + 2 O2 catalyst Na2S2O3 + 2 NaOH + 3 H2O
◼ Removal with molecular sieve
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
6
Molecular structure of cobalt-ftalocyanin
6Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
77
LPG Desulphurisation (MEROX)
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
88
Gasoline desulphurisation
Sulphur compounds in gasoline
Compound Formula Boiling Point, °C
Mercaptans
ethyl-mercaptan C2H5SH 35,0
n-nonyl-mercaptan C9H19SH 220
Sulphides
dimethyl-sulphide CH3-S-CH3 38
n-butyl-sulphide C4H9-S- C4H9 188
Disulphides
dimethyl-disulphide CH3-S-S-CH3 109
ethyl-disulphide C2H5-S-S- C2H5 153
Thiophenes
thiophene
S
80
dimethyl-thiophene S
135
benzothiophene
S
221
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
99
Light gasoline desulphurisation
Sulphur compounds removal by caustic (see LPG)
Reformulation to non-corrosive sulphur compounds („sweetening”)
During „sweetening” the mercaptan is reshaped to the less corrosive
disulphide form, which will remain in the product → the sulphur
concentration will be not changed!!!
2 RSH + 2 OH- → 2 RS- + 2 H2O
2 RS- + cat.0 → RSSR + cat.2-
cat.2- + 1/2O2 + H2O → cat.0 + 2 OH-
(cat.: catalyst, e.g. cobalt-ftalocyanin)
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
1010
Fixed bed MEROX sweetening process
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
1111
Desulphurisation of middle and heavy gasoline
fractions
Examples of hydrodesulphurisation reactions
◼ Mercaptans:
R - S - H + H2 → R - H + H2S
◼ Disulphides:
R1 - S -S - R2 + 3 H2 → R1 - H+ R2 - H + 2 H2S
◼ Thiophenes:
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
1212
Sulphur reduction possibilities of FCC and
pyrolisis gasoline
◼ Selective hydrogenation (industrial application)
◼ Catalytic distillation
◼ Hydrogenation + isomerisation
◼ Alkylation of sulphur compounds
◼ Adsorption
◼ Reactive adsorption
◼ Membrane separation
◼ Extractive distillation
◼ Oxidation of sulphur compounds
◼ Bio-catalytic desulphurisation
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
Typical sulphur and olefin compound
distribution in the FCC gasoline
13
0,7
0,6
0,5
0,4
0,3
0,2
0,1
050 100 150 200
70
60
50
40
30
20
10
0
Olefintartalom
Kéntartalom
Tiofének
Szulfidok, diszulfidok
Merkaptánok
S
CH3CH3
S
CH3
S
C2H5
S
C3H7
C2-S-C1 C2-S-C2 C3-S-C3
C2-S-S-C2
C4-S-C4
C2SH C3SH C4SH C5SH C6SH C7SH C8SH
Kén
tar t
alo
m,%
Forráspont, °C
Ole
fi nta
rtalo
m,%
S
Benzotiofének
S
SS
SS
CH3
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
Boiling point, ˙C
Ole
fin c
on
ten
t, %
Su
lph
ur
co
nte
nt,
%
Olefin content
Sulphur content
Typical composition of the FCC gasoline
14Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
Desulhurisation possibilities (processes)
of total and reduced FCC gasoline fractions
15Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
1616
Hydrodesulphurisation (heteroatom removal)
of petroleum fractions
Sulphur compounds example
220-230°C bp.
sulphur comp.
Nitrogen compounds example
Aniline
Oxygen compounds example
Carboxylic acids
R-COOH C5 ≤ R ≤ C7
R: alkyl-group
NH2
saturated hydrocarbon + H2S
cat., T, P, + H2saturated hydrocarbon + NH3
cat., T, P, + H2
cat., T, P, + H2 saturated hydrocarbon + H2O
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
1717
Desulphurisation of gasoil
Theoretical possibilities:
◼ Hydrodesulphurisation
◼ Adsorption/chemisorption processes
◼ Extraction/partly reactive extraction
◼ Oxidative desulphurisation
◼ Biocatalytic desulphurisation
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
1818
Desulphurisation of gasoil
(heteroatom removal)
Basic reactions
◼ Mercaptans:
R - S - H + H2 → R - H + H2S R ≥ C10
◼ Sulphides:
Open chained:
◼ sulphides: R1 - S - R2 + 2H2 → R1 - H+ R2 - H + H2S
◼ disulphides: R1 - S -S - R2 + 3 H2 → R1 - H+ R2 - H + 2 H2S
Cyclic:
◼ thiophenes:
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
1919
Desulphurisation of gasoil
(heteroatom removal)
◼ benzo-thiophenes:
◼ dibenzo-thiophenes:
+ 3 H2 + H2S
R
S
CH2-CH3
R
S
R R
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
2020
Desulphurisation of gasoil
(heteroatom removal)
Reaction net of dibenzo-thiophene
(Numbers: reaction speed constants, dm3/gcat.s)
S
S S
4,2x10-8 2,8x10-5
1,1x10-44,7x10-5
lassú
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
Alternative desulphurisation reaction pathways
for sterically hindered diaklyl-dibenzo-thiophenes
21Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
2222
Relative reactivity of typical sulphur
compounds
Sulphur compound Formula Relative
reactivity
Thiophenes S
R
1
Benzothiophenes
S
R
0,6
Dibenzothiophenes
S
R R
0,04
4- and/or 6-methyl-
dibenzothiphene S
CH3
CH3
0,004
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
2323
Example reactions of heteroatom removal and
partial dearomatisation of gasoil
Nitrogen removal reactions:
◼ Amines: C18H37 - NH2 + H2 → C18H38 + NH3
◼ Nitriles: C18H37 - CN + 3H2 → C18H37 - CH3 + NH3
◼ Pyrrole-derivatives (pyrrole, indole, carbazole)
◼ Pyridine-derivatives (pyridine, kinoline, acridine)
NH
NH N
H
cat., T, P, + H2Saturated hydrocarbon + NH3
NN N
cat., T, P, + H2Saturated hydrocarbon + NH3
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
2424
Example reactions of heteroatom removal and
partial dearomatisation of gasoil
Oxygen removal reactions:
◼ phenol-deriavatives (alkyl- and allyl-phenols, naphtaleneols)
◼ ketones (tetralones)
◼ furan-derivatives (alkyl-furans, benzofuran, dibenzofuran)
◼ carbonyles (carboxylic acids: R-COOH, aldehydes: R-COH, amides: R-CONH2)
OH
OHR R
O
R
O O O
R
R R
cat., T, P, + H2Hydrocarbon + H2O
cat., T, P, + H2Hydrocarbon + H2O
cat., T, P, + H2Hydrocarbon + H2O
cat., T, P, + H2 Hydrocarbon + H2O ( + NH3)
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
Example reactions of heteroatom removal and
partial (20-40%) dearomatisation of gasoil
25
Mainly the multi ring aromatic partial saturation to mono ring compounds
From naphtalene to decaline:
2H izomerizáció 2H
H2H
R
6H
Three ring aromatic saturation :
R2
R1
+ H2
Katalizátor
R1
R2
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
catalyst
2626
Catalysts for desulphurisation
Catalysts with transition metals (Ni, Co, Mo)
On metal-oxide support (Al2O3, SiO2, TiO2), sometimes zeolite
(feed sulphur content ~250 mg/kg → 1-2%)
e.g.: CoMo/Al2O3; NiMo/Al2O3; CoNiMo/Al2O3
Catalysts with noble metals (Pd, Pt, Re, Ir)
◼ On metal-oxide support (Al2O3, SiO2, TiO2)
◼ On zeolite support (USY, MCM-41, MFI)
(feed sulphur content ≤ 250 mg/kg )
e.g.:Pt-Pd/Al2O3; Pt-Pd/USY
USY: ultra stable Y-type zeolite
MCM: Mesoporous Catalyst Materials
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
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Theoretical scheme of hydrodesulphurisation
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
2828
Typical parameters of desulphurisation of
different fractions
LAGO: light atmospheric gasoil; HAGO: heavy atmospheric gasoil; LVGO: light vacuum gasoil
Feed Gasoline Petroleum LAGO HAGO LVGO
Parameters: TBP cut points, °C Sulphur, % (mg/kg) Process parameters: Temperature, °C Pressure, bar LHSV, h
-1
H2/feed ratio, vol/vol Product sulphur, mg/kg Catalyst cycle life, month Relative catalyst cost, 1/t
70-200
(100-1000)
310-330 20-30
4,0-6,0 100-150
Sulphur removal and production
from hydrogen-sulphide
containing gases
Hydrogen-sulphide removal from high
hydrogen concentration gases
30
(H2, others)
Sweet gas
Sour gas
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
Absorber
Solvent
Stripper
(desorber)
End gas
The reaction (MDEA)
(HO-CH2-CH2)2-N-CH3+H2S
((HO-CH2-CH2)2-N-CH3)+(SH)−
31Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
Most frequently used absorbents
Absorbent MEA DEA MDEA
Molecular weight 61 105 119
Concentration (vol%) 15 30 50
Minimum H2S load (nH2S/namine) 0,05 0,02 0,01
Maximum H2S load (nH2S/namine) 0,6 0,6 0,5
Capacity (H2S/dm3) 1,77 2,18 2,77
32
MEA: mono-ethanol-amine
DEA: di-ethanol-amine
MDEA: methyl-di-ethanol-amine
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
Sulphur production from hydrogen-sulphide
(1) Partial oxidation in the burning chamber H2S + 1,5O2 → SO2 + H2O
or (including the unburnt H2S) 3H2S + 1,5O2 → 2H2S + SO2 + H2O ]
(2) Claus reaction in the burning chamber and in
the catalytic converter2H2S + SO2 → 3S + 2H2O
(1+2) Gross reaction 2H2S + O2 → S2 + 2H2O
COS production H2S + CO2 → COS + H2O
CS2 production CH4 + 2S2 → CS2 + 2H2S
COS hydrolisis COS + H2O → CO2 + H2S
CS2 hydrolisis CS2 + 2H2O → CO2 + 2H2S
33Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
Sulphur production from hydrogen-sulphide
by Claus process
Thermic step: H2S + 1,5 O2 → SO2 + H2O
Catalytic step: 2 H2S + SO2 ↔ 3S + 2 H2O
Véggáz-
tisztító
egységKémény
Termikus
utóégető
Katalitikus
konverter
Katalitikus
konverter
Kén leválasztó
kondenzátorKén leválasztó
kondenzátor
Kén leválasztó
kondenzátor
KénKénKén
Gőz
Hulladékhő
hasznosító
Égető kamra
H2S-ben
dús gázLevegő
H2S/SO2 = 2:1
Előmelegítő Előmelegítő
Víz
Vízgőz
Víz Víz
Vízgőz Vízgőz
34Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
35
Reduction the aromatic
compounds concentration in
gasoil
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
36
Saturation of aromatics in gasoil by
hydrogenation
Importance:
The lower the aromatic content, the better the working
behaviour: higher cetane number, lower exhaust emission
– specifically the particulate matters – middle distillate
production, raw material and energy efficient,
environmentally friendly and economic way.
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
37
Theoretical considerations
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
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Reduction the aromatic compounds
concentration in gasoil
Non-catalytic processes
◼ Acidic refining
◼ Physical separation
adsorption
extractive distillation
Solvent extraction
Liquid membrane permeation
Catalytic processes
◼ Partial or total hydrogenation
(the goal is to convert the aromatics to naphtenes)
◼ hydrocracking (different severity)
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
39
Aromatic compounds in gasoil
Single ring aromatics Two ring aromatics Three ring aromatics
- alkyl-benzenes - Naphtalene and alkyl-
naphtalenes
- antracenes
- benzo-cycloparaffins - bifenyls - fenantrenes
-benzo-dicycloparaffins - naphteno-aromatics (indenes) - fluorenes
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
40
Saturation of aromatics
Highly exotherm reaction
alkyl-benzene to alkyl-cyclohexane
(reaction time increases with the alkyl chain size; exothermicity decreases)
Naphthalene to decaline: ∆H = -335 kJ/mol
2H izomerizáció 2H
H2H
R
6H
2H 2H 2H 2H
gyűrűfel-szakadás
szénhidrogén
R R R R
toluene → methyl-cyclohexane: ∆H = -205 kJ/mol
ethyl-benzene → ethyl-cyclohexane: ∆H = -202 kJ/mol
cumene → 2-cyclohexyl-propane: ∆H = -184 kJ/mol
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
hydrocarbonRing
rapture
41
Kinetic and thermodynamic factors determining
the hydrogenation of aromatic compounds
Tkinetika Tterm.
Aro
má
sta
rta
lom
, ft
f %
Hőmérséklet, °C
P = 50 bar
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
Transition metal/support
Noble metal/support
Temperature,
Aro
ma
tic c
on
ten
t, v
ol%
42
Catalysts for aromatic hydrogenation
Highly sulphur tolerant catalysts
(feed sulphur content ≥ 250 mg/kg)
◼ Mo, W (VI. group) and Co, Ni (VIII. group) in suphided form, on γ-Al2O3 support
Activity sequence: Mo > W >> Ni > Co
◼ NiMo/Al2O3, CoMo/Al2O3, NiW/Al2O3 in sulphided form
Activity sequence: NiW > NiMo > CoMo > CoW
◼ Partial aromatic saturation (up to ~50-80 %; at least 60 bar H2 partial pressure)
Low sulphur tolerant catalysts
(feed sulphur content 250 mg/kg, more typically 10-20 mg/kg)
◼ Pt or Pt, Pd amorphous Al2O3 – SiO2, or on acidic (USY) support
◼ High level aromatic saturation (up to ~95 %; Tmax: 300-310 °C, pH2: 25-40 bar)
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
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Industrial applications
Differences in applications:
In the sequence of heteroatom removal and aromatic saturation (in teh same time or in sequence);
In the number of reactors applied;
In the catalyst(s) applied;
In the mode of catalyst distribution (e.g. divided bed);
In the mode of feed introduction to the catalyst bed;
In the mode of quench cooling;
In the used process parameters, etc.
The industrial applications may be classified into two main groups:
Single stage processes
Two stage processes
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
44
Sketch of the single stage aromatic reduction
of gasoil
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
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Sketch of the two stage aromatic reduction of
gasoil
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
46
Catalytic reshaping of normal-
paraffins in gasoil
(„paraffin removal”)
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
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Catalytic reshaping of normal-paraffins in
gasoil
Importance
The goal is to convert the high freezing point normal paraffins to lower
freezing point ones (decrease of cold filtration point – CFPP)
Freezing point reduction possibilities
❑ Selective hydrocracking
❑ Selective isomerisation
❑ Combination of the two above
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
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Theoretical considerations of freezing point vs
carbon number
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
-100
-80
-60
-40
-20
0
20
40
60
Fre
ezin
g p
oin
t, °
C
Carbon number
nincs
2-metil
5-metil
1312 16 18 20 22
Side chain
DT=60°C DT=64°C
DT=59°C
DT=48°C
DT=44°C
none
2-methyl
5-methyl
4949
Catalytic reshaping of normal-paraffins in
gasoil
Catalyst examples:
◼ Ni/ZSM-5 (mainly hydrocracking)
◼ Pt/SAPO-11, Pt/HZSM-22 (mainly isomerisation)
Process parameters
◼ Temperature: 330 – 370°C
◼ Pressure: 30 – 50 bar
◼ LHSV: 1,0 – 2,0 m3/m3h
◼ H2/hydrocarbon ratio: 250 – 300 Nm3/m3
Product yield: 80 – 95 %
Freezing point drop (ΔT): 15 – 25°C
Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
Recommended literature
Hancsók, J., Baladincz, J., Magyar, J. (szerkesztők): „Mobilitás és környezet”, gyűjteményes kiadvány, 2008,
Pannon Egyetemi Kiadó, Veszprém (ISBN: 978-963-9696-50-1), 240 oldal
Srivastava, S. P., Hancsók, J.: „Fuels and Fuel-Additives”, 2014, John Wiley & Sons, Inc., Hoboken, New Jersey,
(ISBN: 978-0-470-90186-1), 376 oldal
Hancsók.Jenő.:Korszerű motor- és sugárhajtómű üzemanyagok II. Dízelgázolajok, tankönyv, Veszprémi Egyetemi
Kiadó 1999.
Hancsók Jenő, Kasza Tamás: „Katalitikus hidrogénező eljárások a kőolajiparban”, Oktatási segédlet, Veszprém,
2010.
Magyar Kémikusok Lapja következő számai: 2005/6-12, 2006/1-12, 2007/1-7
Gary, J.H.: Petroleum Refining Technology and Economics 3rd , Marcel Dekker, N.Y. 2004.
Speight,J.G.: The chemistry and technology of petroleum 3rd . Marcell Dekker, 1999.
Speight,J.G.: Petroleum Chemistry and Refining, Taylor and Francis 2006.
Weissermel, K., Arpe, H-J.: Ipari szerves kémia, Nemzeti Tankönyvkiadó, Budapest, 1993.
Mc Ketta, J.: Petroleum Processing Handbook, Marcell Dekker, 1992.
Hobson, G.D.: Modern Petroleum Technology, J. Wiley, 1986.
Meyers, R.A.: Handbook of petroleum Refining Processes, McGraw-Hill Inc., N.Y., Toronto, 2007.
Olah, G.A., Molnár, Á.: Hydrocarbon chemistry, John Wiley and Sons, Inc., 2003.
50Jenő Hancsók: Hydrocarbon processing, BME, 08.10.2014., Copyright
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Thank you for your attention!