ExxonMobil Advances in Distillate Dewaxing

Research and Engineering
ExxonMobil Advances in
Distillate Dewaxing
Maximizing Production of Premium Diesel
Using ExxonMobil’s MIDWTM Technology
Dr. S. Hantzer, T. Hilbert , Dr. S. Tabak
and Dr. Z. Hou
China Downstream Technology Conference
May 17-18, 2011, Tianjin
Options to Low Cloud and Low Pour Diesel
• As temperature drops, the native wax molecules found in diesel begins to
form crystals and solidify
– These crystals can prove problematic and can clog fuel filters / prevent engine
startup
• Cold flow improvements are tracked by either cloud point or pour point
– Cloud point is the temperature at which wax crystals begin to precipitate from a
petroleum sample
– Pour point is the temperature at which oil ceases to flow
• Several approaches to improving cold flow properties in diesel
– Additives, undercutting, diluting w/ kerosene and
solvent dewaxing
– All of these have significant disadvantages including high costs
and significant diesel yield loss
• Catalytic Dewaxing provides a competitive alternative
China Downstream Technology Conference
May 17-18, 2011, Tianjin
2
Cold Flow Improvement Can be Achieved by Cracking Wax
• Historical process - Dewaxing by Selective Cracking: MDDW™
n-paraffin freely enters zeolite
• Selectively crack long chain n-paraffins to form shorter chains
– Reject iso-, aromatic and naphthenic molecules for improved yields
– Problem – high loss to lights because of pure cracking and no isomerization
iso-paraffins are blocked
from entering zeolite
alkyl groups enter zeolite
up to ring
China Downstream Technology Conference
May 17-18, 2011, Tianjin
3
What is MIDW
?
• First announced at the 1996 ERTC
Conference
Gas Chromatograms
90°F Pour Point
Minas Feed
n-Paraffins
• Selective Catalytic Dewaxing Process
• Improves diesel cold flow properties:
– Pour point
– Cloud point
– CFPP (cold filtration test)
20°F Pour Point
MIDW
 Product
Isoparaffins
• Other benefits:
– Allows feed end-point extension
– Improves cetane and density
• Applicable to kerosene and HDC
bottoms
165
• Flexible Process Configurations
343
427
Boiling Point, °C
China Downstream Technology Conference
May 17-18, 2011, Tianjin
4
MIDW Chemistry
• Dewaxing by Selective Isomerization: MIDW
– Mobil Isomerization DeWaxing (MIDW) technology contains a metal capable of
dehydrogenation/hydrogenation reactions and a zeolite for shape selective skeletal
isomerization of n-paraffins to iso-paraffins
– Reduces loss of feed material to light gases and naphtha through cracking
n-paraffin molecule
(poor cold flow)
branched paraffin molecule
(good cold flow)
ZEOLITE CATALST
LARGE MOLECULE
CANNOT ENTER
ZEOLITE PORE
isomerized molecule
unchanged bulky
molecule
China Downstream Technology Conference
May 17-18, 2011, Tianjin
5
The Chemistry Behind Catalytic Dewaxing
Isomerization-Dewaxing Chemistry for Cloud Point Improvement
H
H
H H H
H – C – C – C – C – C –H
H n H H H
H m
Dehydrogenation
(Metal Site)
H
H
H H H
H – C – C = C – C – C – H + H2
H n
H m
H
+ H+
Cracking to
Linear Olefin +
Primary Carbenium Ion
(Energetically Disfavored)
(Acid Site on Zeolite)
H
H
H H
C
–
–
–
–
H
C
C C
H n
H
C H+
–H
m
H H
– H+
H
H
H H H
C – C – C – C – C –H
H n | H H
H m-1
C
H H
Hydrogenation
(Metal Site)
(Acid Site on Zeolite)
H
H
H H H
H – C – C – C = C – C –H
H n |
H m-1
C
H H
China Downstream Technology Conference
May 17-18, 2011, Tianjin
6
MIDW Commercial Experience
• Growing worldwide interest in MIDW
• Eight (8) commercial units
Location
Start Up
Asia Pacific (a)
1990
USA
1996
USA
1999
Europe
2001
Canada
2005
Canada
2006
Asia
2009
Canada (a)
2009
Russia
Europe
Under design
Under design
a) ExxonMobil refinery
• Two (2) additional units under design
China Downstream Technology Conference
May 17-18, 2011, Tianjin
7
Summary of Options for Using MIDW
• High flexibility, four process configurations have been commercialized
Moderate
S, N
Low Pour
High Cetane Diesel
MIDW
Waxy Feed
HDT
Lower Reactor Temperatures
Low Sulfur Distillates
MIDW
H2S, NH3
High S, N
HDT
MIDW
Lower Reactor Temperatures
Higher Distillate Yields
MIDW
Premium Quality Distillates
Low Pour Point Bottoms
Long Catalyst Life
H2S, NH3 , Distillates
VGO Feed
MPHC
China Downstream Technology Conference
May 17-18, 2011, Tianjin
8
Sour Feed MIDW Units
• One or Two multi-bed reactor configurations
– Ability to quench or by-pass MIDW bed for summer mode to preserve catalyst
activity
• Experience with high-activity HDT catalyst for increased nitrogen removal
• Post-treat catalyst bed to prevent EOC mercaptan reversion
1-Reactor Configuration
2-Reactor Configuration
HDT Rxr
MIDW Rxr
Quench
High Activity
HDT Beds
High Activity
HDT Beds
MIDW Bed
Quench
MIDW Bed
Optional R2 Bypass
China Downstream Technology Conference
May 17-18, 2011, Tianjin
9
MIDW can be Designed and Operated in Two Modes
• Increases unit flexibility
• Allows feed end-point extension while producing on specs
high quality low pour, low cloud diesel
Summer Operation
(no MIDW)
API
Sulfur
wppm
Cetane Index
D976
90% point
°C
Cloud
°C
Naphtha
vol%
Winter Operation
(with MIDW)
M
I
D
W
Winter
Summer
Feed
Product
Delta
Feed
Product
Delta
36.3
38.2
1.9
35.3
39.4
4.1
2,500
1.6
4,800
0.5
49.5
52.2
2.7
48.6
51.2
2.6
319
319
0
327
314
13
-10
-10
0
-8
-27
-19
3.3
H
D
T
6.9
China Downstream Technology Conference
May 17-18, 2011, Tianjin
10
Ultra Low Sulfur Diesel Production with Flexible Cloud Point
0.7 °C per month after first 30-days of operation
Temperature, °C
– 3-years cycle length
– Feed: 0.3 wt% Sulfur and 130 wppm Nitrogen
– <10 wppm Sulfur product
H
D
T
40
50
20
40
Base 0
30
Winter
20
M
I
D
W
Winter
Summer
Cloud Point Reduction, °C
• Low aging rate:
10
Summer
0
100
200
300
400
500
600
700
800
0
900
Days-On-Stream
China Downstream Technology Conference
May 17-18, 2011, Tianjin
11
Feed End-point Extension to Increase Diesel Production
• Moderate end-point reduction capabilities allows to process heavier feeds
while achieving high quality product
– Increased low pour, low cloud diesel production
Feed & Product T95 (D86) ° C
380
Feed T95
Product T95
370
360
350
340
330
320
0
20
40
60
80
100
Days on Oil
China Downstream Technology Conference
May 17-18, 2011, Tianjin
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Sweet Operation Allows Ultra Low Cloud Points
Fig. 5 Refinery D Feed and Product Cloud Points
10
0
Cloud Point, C
-10
-20
Feed
-30
Heavy Distillate
-40
Light Distillate
-50
-60
Detection
Detection Limit
Limit
-70
-80
0
20
40
60
80
100
120
140
160
Days-On-Stream
China Downstream Technology Conference
May 17-18, 2011, Tianjin
13
MPHC as Pre-treat for FCC Unit
(Persian Gulf Feed, 100 kBD [16 tm3/d] to FCC Unit)
• Increased diesel production and quality at constant FCC rate
VGO Rates
kBD (tm3/d)
Rates
Product
kBD (tm3/d) Properties
100 (16)
118 (19)
FCC
&
Alkylation
CFHT
Heavy Fuel Oil
(<500 wppm S)
200 (32)
FCC
&
Alkylation
MPHC Heavy Fuel Oil
(<500 wppm S)
FCC
&
Alkylation
Alkylate
27 ( 4.3)
Gasoline
69 (11.0)
High Sulfur
LCO
11 ( 1.7)
High Sulfur
CSO
6 ( 0.9)
High Sulfur
Naphtha
2 ( 0.3)
Diesel
16 ( 2.5)
Alkylate
31 ( 4.9)
Gasoline
74 (11.8)
Low Sulfur
LCO
5 ( 0.8)
Low Sulfur
CSO
3 ( 0.5)
Diesel
kBD (tm3/d) Quality
11 ( 1.7)
Low
21 ( 3.3)
Medium
85 (13.5)
High
Low Sulfur
Naphtha
20 ( 3.2)
Diesel
80 (12.7)
Alkylate
37 ( 5.9)
Gasoline
72 (11.4)
Low Sulfur
LCO
5 ( 0.8)
Low Sulfur
CSO
3 ( 0.5)
Low Sulfur
China Downstream Technology Conference
May 17-18, 2011, Tianjin
14
Premium Quality Kerosene and Diesel from HVGO with MIDW
• Integrated MPHC / MIDW Process
–
–
–
–
Feed to MPHC: HVGO/MVGO blend with 1.2 wt% Sulfur and 1,800 wppm Nitrogen
MPHC operates at 35-40% 387°C+ conversion ; Combined conversion >65%
Premium Kerosene and Diesel from MIDW
Stable production and long cycle length for MIDW
FeedStock
to MIDW
Naphtha
Kerosene
Diesel
LSHFO
337 – 510
C5 – 150
150 – 260
260 – 387
387+
Yields, wt%
100.0
9.7
13.6
24.7
50.7
Gravity, °API
32.0
73.0
49.5
34.7
29.5
Sulfur, wppm
200
<1
<2
< 15
40
Smoke Point, mm
—
—
32
—
—
Freeze Point, °C
—
—
< -54
—
—
Pour Point, °C
> 38
—
—
-43
-7
Cetane Index
—
—
52
56
—
P / N / A, wt%
44 / 39 / 17
—
— / — / 10
45 / 31 / 24
36 / 42 / 22
Boiling Range, °C
China Downstream Technology Conference
May 17-18, 2011, Tianjin
15
EMRE
Continues to
Make
Advances in
Dewaxing
New Generation
MIDW Catalyst
MIDW Catalyst Operates with Excellent Diesel Selectivity
• Diesel selectivity is controlled by:
– Zeolite type and formulation
– Process conditions
300°F+ (150°C+) Yield, wt%
100
MIDW Operating “Range”
Isomerization Technology
90
80
MDDW Operating “Line”
70
Cracking Technology
60
50
0
11
22
33
44
55
Cloud Point Reduction, °C
China Downstream Technology Conference
May 17-18, 2011, Tianjin
17
The Drive for a Better Catalyst
2-Reactor Configuration
HDT Rxr
High Activity
NiMo HDT
Beds
MIDW Rxr
Quench
MIDW
Bed
1-Reactor Configuration
High Activity
NiMo HDT Beds
Quench
MIDW
Bed
Optional R2
Bypass
• For 2- Reactor Configurations:
– Additional activity allows for
longer cycle lengths to match up
with HDT catalyst cycle lengths
• For 1- Reactor Configurations:
– Additional Activity allows dewaxing
at typical HDT temps for applications
with limited bed volume and high
LHSV
China Downstream Technology Conference
May 17-18, 2011, Tianjin
18
New Generation of MIDW Shows Significant
Improvement over Previous Generation
10-14°C Delta Cloud Improvement
140
Delta Cloud ( °C)
120
100
80
60
40
20
0
332
338
343
349
354
360
366
371
Temperature ( °C)
MIDW
New Generation MIDW
China Downstream Technology Conference
May 17-18, 2011, Tianjin
19
Dewaxing in Bio Applications
Applications of MIDW to Improve
Cold Flow Properties of Renewable Diesels
• Strong push for increased biocontent in motor fuels
– Fuel supply security
– Reduced environmental impact,
mainly GHG’s
• Biofuel sources include: Palm Oil,
Rapeseed Oil, & Soy Bean Oil
• Renewable diesel fuels typically
have good diesel properties except
cold flow
– Hydrotreating of biofuel precursors
results in significant amounts of nparaffinic materials
• MIDW catalysts ideal for the
selective isomerization of nparaffinic materials
Obligation
Tax incentives only
Limited support
China Downstream Technology Conference
May 17-18, 2011, Tianjin
21
MIDW Effectiveness
• MIDW technology is effective for isomerizing renewable diesel
• Substantial cold flow improvements
nC-20
nC-18
nC-19
nC-14
nC-13
Isomerized Renewable Diesel
nC-16
nC-15
Renewable Diesel
nC-17
– Various cloud/pour points can be achieved depending on regional
requirements
China Downstream Technology Conference
May 17-18, 2011, Tianjin
22
-33°C Cloud Point Achieved at Low Temperature ( <330°C)
China Downstream Technology Conference
May 17-18, 2011, Tianjin
23
Summary
• MIDW is a commercially proven technology
• Low cloud point (-40°C) can be achieved without blending
• MIDW catalyst is robust and stable
• Feed end-point extension to increase diesel production
•
Four MIDW process configurations commercially proven
• Integrated MPHC/MIDW configuration can produce high yields of premium
diesel and kerosene from HVGO
• A more active MIDW catalyst has been developed which will help expand
the technology use by allowing retrofits in more hydroprocessing reactors
• EMRE is well positioned to assist customers in meeting their diesel
production requirements
• MIDW can be used for Bio hydroisomerization
China Downstream Technology Conference
May 17-18, 2011, Tianjin
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