Improving refinery profitability with light, high mercaptan CPC Blend

and heavy, high TAN Doba Blend using Chevron Pembroke refinery
as a Case Study

Alex Kokashinsky
Upstream/Downstream Commercial Adviser

Presented at
The European Refining Technology Conference
November, 2005 Vienna, Austria

© Chevron 2005

Introduction

• Significant growth in Caspian crude oil exports associated mainly with the
development of sizeable new production in Kazakhstan, the expansion of CPC
pipeline, and the commissioning of the BTC pipeline will result in substantial
increase in the availability of light oil in the Atlantic basin and create
opportunities for refineries.

• Coupled with this is an increasing availability of heavier, high acid crude oils
from West and Central Africa and new streams coming on line in the North Sea
which have provided an excellent opportunity for the Chevron Pembroke
refinery to optimise the crude slate and maximise profitability by processing a
blend of light, high mercaptan and heavy, high TAN crudes.

• A trial run of CPC Blend in combination with Doba was prepared with support
from UOP, the Merox technology provider, and successfully executed at
Chevron’s Pembroke refinery in the first half of 2005.

• This paper will overview the supply chain, economic drivers, processing
challenges, indicative test results, and recommended unit modifications for
processing the blend using Pembroke Refinery as a case study.

1
 Agenda

ƒ CPC Blend and Doba: supply chain and key properties

ƒ Refinery crude oil sourcing opportunities

ƒ CPC Blend marketing

ƒ Economic drivers to process high mercaptan / high TAN blend

ƒ Main processing challenges faced

ƒ Pembroke refinery case study

ƒ MeroxTM design and key uncertainties
ƒ UOP recommendations and trial run results
ƒ Recommended modifications and way forward

© Chevron 2005 2

• This paper will cover general aspects of CPC Blend and Doba crude oil production
forecasts, key crude oil and product properties, the supply chain, and marketing.

• It will discuss opportunities created for European refiners by increasing production

and export of light, high mercaptan crude oil from Kazakhstan and the growing
supply of heavy, high acid crude (HAC) oil from West and Central Africa and the
North Sea.

• The paper briefly explores the economic drivers to increase processing of light,
high mercaptan CPC Blend from the Caspian and heavy, high TAN Doba from
Chad based on a generic North West European catalytic cracking refinery example.

• It will then shift focus to address key uncertainties that the Pembroke refinery
faced before the trial, cover hardware and procedural modifications recommended
by UOP to make the trial successful, and talk about conditions of the trial and
results.

• In conclusion, the paper covers recommended process and design modifications

necessary to increase the CPC Blend processing rate up to 40% of the crude slate.

2
 CPC Blend at a glance

CPC Blend Quality Features (Average) CPC Blend Volumes, million tonnes per annum
50 35 650 MBPD
°API 0.95
45 47.2 47.2 46.9 30
44.7 470 MBPD Russian crude
43.3 0.85 25
40 Arman
0.75 20 Martyshi
35 320 MBPD
15 250 MBPD Kumkol
30 0.65 Aktobe
Sulphur, wt % 10
0.59 0.55 Karachaganak
25 0.50 0.50 0.57 5 Start up Tengiz
0.52
20 0
2001 2002 2003 2004 2005(e) 2001 2002 2003 2004 2005 (e)
© Chevron 2005 3

• CPC Blend is a light crude oil which was first introduced to the market at the end
of 2001 with the commissioning of a 1,580 km pipeline by the Caspian Pipeline
Consortium (CPC).

• The CPC pipeline links major oil fields in Western Kazakhstan and Russia to a
new Black Sea export terminal near Novorossiysk (Russia). The 2005 CPC Blend
composition includes Tengiz, Aktobe, Kumkol, Martyshi, Arman, Karachaganak
and Russian light crude oils.

• CPC Blend is a light (43°API), medium sour (0.6 wt% sulphur) crude oil. Sales of
CPC Blend started as pure Tengiz crude oil in 2001. Injection of other crudes in
later years contributed to quality changes and rapid volume expansion.

• The current export volumes are approaching 650,000 barrels per day. Pipeline
expansions are expected to increase capacity to 1,340,000 barrels per day by the
end of the decade.

3
 CPC Blend Properties & Product Yields

Benchmark Crude Oil CPC Blend Qatar Saharan Liverpool Tengiz WTI Brent Urals
Condens. Blend Bay
Gravity °API 43.3 56.5 45.7 44.8 47.2 39.1 37.9 32.2
Sulphur %wt 0.59 0.24 0.10 0.22 0.55 0.37 0.45 1.54
Nitrogen ppm 421 11 269 161 180 998 1050 1610
Total Acid Number Mg.KOH/g 0.10 0.03 0.03 0.02 0.06 0.09 0.03 0.03
Pour point °C -22 2 -42 -1 -32 -21 -4 -4
Viscosity @ 40°C, cSt 2.35 0.85 1.82 2.16 1.66 3.30 3.64 8.34
Mercaptans in Jet/Kero ppm 581 868 1 1030 697 48 1 159

Straight Run Product Yields

100%

80%
% Volume Yields

60%

40%

20%

0% CPC Blend Qatar Saharan Liverpool Tengiz Murban WTI Brent Urals
Condens. Blend Bay
LPG Light Gasoline Naphtha Kerosene Gas Oil VGO Vacuum Resid
© Chevron 2005 4

• CPC Blend is a light crude oil ideal for increasing light product yields in a refinery.

• Straight run product yields of CPC Blend are similar to those of Saharan Blend,
Liverpool Bay, and Murban with high yields of naphtha and middle distillates.

• Due to elevated levels of mercaptans and sulphur, CPC Blend naphtha and middle
distillates require sweetening to meet stringent EU product specifications on
sulphur.

• The Naphtha has a relatively high level of naphthenes and aromatics (N+2A)
making it an excellent reformer feed.

• Both kerosene/jet and gas oil meet product specifications on cetane and smoke
point.

• A high aniline point and “K Factor” coupled with low nitrogen and modest sulphur
content result in excellent conversion in catalytic crackers or hydrocrackers.

• Yielding only 6% vacuum bottoms makes CPC Blend an attractive crude for
refineries with little or no residuum conversion capacity and those refineries who
want to limit fuel oil production. Any fuel oil produced requires blending to meet
the inland EU specification on sulphur.

4
 Doba Blend Overview

Lake
Chad LPG Naphtha Atm. Gas Oil
NDjamena
Gasoline Kerosene VGO Vac Resid
CHAD 100
NIGERIA
90
80

% Volume Yields
Moundou
Doba 70
Ngaoundere
60

Ngoundal 50
CENTRAL
AFRICAN 40
CAMEROON
REPUBLIC
30
Douala
Yaounde
20
Kribi CONGO 10
Atlantic
Ocean
0
Doba Captain Alba Grane Clair Heidrun

Doba Blend Captain Alba Grane Clair Heidrun

Gravity °API 21.1 19.7 19.4 18.5 23.7 27.5
Sulfur wt % 0.10 0.65 1.25 0.81 0.44 0.47
Acid Number mg KOH/g 4.1 2.4 1.4 2.2 1.2 2.6
Pour Point °C -5 -29 -37 -27 -32 -48
Viscosity, at 40°C cSt 280 138 134 100 46 10
© Chevron 2005 5

• Doba Export Blend is a heavy, low sulphur crude produced from the Doba Basin in
the southern region of the Republic of Chad. The production is transported via
pipeline from the Doba Basin, through Cameroon to a Floating Storage Offloading
(FSO) vessel located offshore near the province of Kribi.

• Peak production for the next 4-5 years is not expected to exceed 225 MBPD. The
reservoir volume is estimated at 1 billion barrels for a field life of 15+ years.

• Doba has characteristics typical of mature, biodegraded crudes. It is quite heavy at

21°API, and has low asphaltenes, sulphur, and nitrogen levels. Doba produces a
high yield of low sulphur (0.1%wt) VGO providing benefits for producing low
sulphur gasoline.

• Doba has high residual yield with good qualities including low sulphur, viscosity,
Con Carbon, and high paraffinicity. Residuum from Doba will result in a very low
coke yield and hydrogen-rich conversion products in refineries with residuum
conversion capabilities.

• Doba VGO has corrosivity slightly higher than Captain and less than Heidrun.

• Doba contains 300 ppm of calcium. The calcium is predominantly organic and is
concentrated in the vacuum residuum. The calcium can be partially removed in
desalters by injecting special chemicals.

5
 Refinery Crude Oil Sourcing Opportunities

High Mercaptan Crude Oil Supply Heavy High Acid Crude Oil Supply
MBPD MBPD
2,750 1,000
CPC Blend Tengiz Kashagan
2,500 900
2,250 800
2,000 700
1,750
600
1,500
500
1,250
400 Doba
1,000 Clair
750 300 Captain
200 Alba
500 Grane
250 100 Heidrun
Troll Blend
0 0
2003 2004 2005 2006 2007 2008 2009 2010 2015 2020 2004 2005 2006 2007 2008 2009 2010
Source: Chevron Source: Wood Mackenzie

CPC Blend Quality Outlook 2004A 2005E 2006E 2007E 2008E 2009E
Whole Crude Gravity, °API 44.7 43.3 42.5 42.4 43.2 43.8
Whole Crude Sulphur, wt % 0.57 0.59 0.60 0.59 0.58 0.57
Raw Kerosene Mercaptan, ppm 649 589 554 543 569 589

© Chevron 2005 6

• The supply of light, high mercaptan crude from Kazakhstan is expected to more
than triple by 2020 to around 2,500 thousand barrels per day.

• A significant CPC Blend volume increase is expected by 2008 as a result of a

planned CPC pipeline expansion.

• Expansion of the Tengiz field, the largest single component of the blend, is
expected in late 2006. The incremental 260,000 barrel per day from the field
expansion will be marketed as pure Tengiz through a variety of outlets (rail, etc.)
until the CPC expansion is commissioned.

• Post expansion, CPC Blend quality is forecast to remain light, medium sulphur.
The mercaptan content in the kerosene/jet cut is likely to remain largely
unchanged.

• The super-giant Kashagan field in Western Kazakhstan (estimated peak output is

around 1.3-1.5 million barrels per day) is expected to start production by 2009.
Crude oil is likely to be of similar properties to Tengiz. Although some Kashagan
export volumes may find space in the CPC pipeline, the majority of production will
find its way to the market via other routes.

• While the World production of heavy, high acid crudes has expanded in recent
years, particularly in Africa (Chad, Angola) and the Far East, the North Sea
production is expected to enter a gradual decline starting in 2006. None-the-less,
new crudes like Grane (Norway) and Clair (UK) have just come on stream and
represent long-term opportunity for the local substitution and diversification of
European refinery sourcing choices.

6
 CPC Blend Marketing

2003 CPC Blend Export Structure CPC Blend CIF Augusta vs. Saharan Blend FOB
Far East 4% 2002 2003 2004 2005YTD
Americas 3% 0.0
-0.2
N.W.Europe 250 MBPD
-0.4

$ per bbl
14%
-0.6 320 MBPD
-0.8
Mediterranean
-1.0
79%
-1.2 470 MBPD
-1.4 650 MBPD

2004 CPC Blend Export Structure 2005 YTD CPC Blend Export Structure
US Gulf Coast 6% Far East 0% Far East 1%
US Gulf Coast 8%

N.W.Europe
20% N.W.Europe
16%
Mediterranean Mediterranean
74% 75%

© Chevron 2005 Source: Chevron 7

• CPC Blend production has more than doubled since 2003.

• The CPC Blend – Saharan Blend spread has grown by over a $1.00 per barrel since
2002 (as reported by Platts) reflecting wider sweet/sour spread and CPC Blend’s
increased supply.

• Although the Med market consumption has expanded in the recent years, its
relative share in total CPC Blend sales has declined from 79% in 2003 to 75% in
the first half of 2005. North Western Europe and US Gulf Coast are now
established alternative markets.

• The European refinery system is dominated by catalytic cracking capacity and

would benefit from refining grades heavier than CPC Blend to maintain high FCC
utilization rates. At 43°API, CPC Blend is much lighter than the average European
crude slate. The ability to feed light high mercaptan CPC Blend crude oil at high
rates may require blending with heavier crude grades to supply straight run residue
to match refinery plant capacities.

• The relatively high mercaptan level in CPC Blend and rapid output growth has
expanded the market for CPC Blend beyond the Mediterranean and made it an
opportunity crude for North Western Europe and the US Gulf Coast.

7
 CPC-Doba Economic Benefits
Pembroke Refinery Case Study

Incremental NWE cat cracking Straight Run Product Yields, vol %

margin versus Brent margin
100%
Blend B 90% LPG

45% Statfjord + 40% CPC Blend 80% Gasoline

+ 15% Doba $2.28/bbl
70%
60% Naphtha

50% Kerosene
Blend A 40%
Atm Gas Oil
80% Statfjord + 30%
20% Captain $1.63/bbl
20% VGO
10%
$/bbl Vac Resid
0%
0.00 0.50 1.00 1.50 2.00 2.50 Brent Blend A Blend B

Gravity Sulfur TAN Pour Point Viscosity, at 40°C Jet RSH

°API wt % mg KOH/g °C cSt ppm
Brent 37.9 0.45 0.03 -4 3.64 1
Blend A 34.9 0.32 0.32 -4 6.47 2
Blend B 37.7 0.34 0.85 -7 4.75 272

CPC
CPCBlend
Blendrepresents
representsaaprocessing
processingsynergy
synergyififrefined
refinedwith
withheavy
heavysweet
sweethigh
highacid
acidDoba.
Doba.
The
Theblend
blendyields
yieldsincremental
incrementalmargins
marginsinincat
catcracking
crackingrefineries
refineries
© Chevron 2005 8

• The combination of 15% Doba, 40% CPC and 45% light sweet North Sea crudes
(e.g. Statfjord, Ekofisk, Oseberg) is producing a blend (Blend B) with crude
properties (gravity, sulphur, viscosity, etc.) and straight run product yield structure
similar to that of Brent but characterized by much higher corrosivity and mercaptan
content.

• Simulation of processing Blend B in a generic FCC refinery with a visbreaker

located in Rotterdam resulted in an incremental margin versus Brent of $2.28 per
bbl based on average freight rates, and crude oil and product prices from July 2004
to June 2005 as reported by Platts.

• Blend A, consisting of 80% Statfjord and 20% Captain, both crudes produced in
the North Sea, yielded only $1.63 per bbl incremental margin versus Brent.

• Although the FCC refinery benefited from the gross product value uplift while
processing Blend B versus Brent, the key profitability driver was attractive landed
value of Doba and CPC Blend crudes.

• Our analysis indicates that the ability to process the combination of Doba, CPC
Blend and light sweet North Sea crude may result in a substantial incremental
margin in a European cracking refinery.

8
 Blend Processing Challenges
High Mercaptan & High Acid Crude Oil

- CPC Blend
LPG Mercaptan
LPG Merox Treatment
- Doba Blend
- Logistics
Naphtha Naphtha
Reformer
Hydrotreater
Potential Odour CDU Overheads
Issues

Kerosene Kerosene Merox / HDT Naphtha HDT

Jetty Merox Constraints Constraints

Crude
Crude Unit Straight Run Diesel
Tank Diesel Hydrotreater
Farm

Vacuum VGO FCCU

Unit
Atmospheric
Crude Farm Tank Residue Corrosion
Limitations Prevention

Metal Removal in Vacuum Residue

Visbreaker
Desalter

© Chevron 2005 9

• Refineries should have sealed crude import systems, crude tanks, and crude feed
system along with strict waste water treatment procedures to handle CPC Blend
without incident (odour release). In addition, specific instructions should be given
to a cargo ship carrying CPC Blend to prevent venting.

• CPC and Doba crude oils are delivered in 600,000 bbl and 1,000,000 bbl parcels
and, typically, need to be stored segregated from other streams. Discharging Doba
can be an issue due to its high viscosity and pour point.

• In order to meet product specifications on mercaptan levels, a refinery should have

sufficient hydrotreating and/or Merox capacity to treat the naphtha and kerosene/jet
cuts.

• Doba has elevated levels of calcium. Effective metal removal in the desalter may
be an issue.

• Naphthenic acid content is highest in the VGO cut of HAC and needs to be
managed to prevent damage to the equipment. Various methods have been
developed and implemented to successfully manage corrosivity.

9
 Merox Design & Key Uncertainties
Pembroke Refinery Case Study

ƒ The RSH content of the CDU LPG stream could be enhanced by the decomposition of
disulphide oil which is added to the crude as a result of sweetening at the field
ƒ Propane is untreated
ƒ Butane Merox performance is uncertain
Butane Merox Design Raw Butane Raw Butane Flow Max Capacity Finished Product
Basis RSH Rate (m3/h) (m3/h) RSH
Original Design <150 ppm 95.7 <5 ppm
CPC Blend (at 40%) uncertainty 125 uncertainty

ƒ Kerosene Merox unit performance at above design throughput and mercaptan levels
ƒ Mercaptan levels in finished product
ƒ Water saturation (kerosene haze)

Kerosene Merox Raw Kerosene Raw Kerosene Flow Max Capacity Finished Product
Design Basis RSH Rate (m3/h) (m3/h) RSH
Original Design <160 ppm 200 <5 ppm
CPC Blend (at 40%) up to 400 ppm 223 uncertainty

Pembroke
Pembrokepartnered
partneredwith
withUOP
UOPto toreview
reviewdesign
designbasis
basisand
andprocess
process
modifications
modifications necessary to refine incremental volumesof
necessary to refine incremental volumes ofCPC
CPCBlend
Blend
© Chevron 2005 10

• The Pembroke refinery is using MeroxTM units designed by UOP to treat

mercaptans in butane and kerosene/jet fuel stream. Naphtha and diesel are
hydrotreated while the propane stream remains untreated.

• The Butane Merox unit was originally designed to sweeten CDU and imported
butane from 150 ppm down to 5 ppm RSH at max 95.7 m3/h flow rate.

• The Kerosene Merox unit was originally designed in 1971 and subsequently
revamped to achieve a 200 m3/h flow rate and be able to sweeten raw kerosene
with up to 160 ppm RSH to meet Jet A-1 specifications.

• In order to meet CPC pipeline specification of <30 ppm of methyl & ethyl
mercaptans, de-mercaptanization is performed at the field by oxidizing methyl (C1)
and ethyl (C2) RSH to create disulphides that remain in the blend. Decomposition
could potentially occur in the CDU causing elevated levels of mercaptans in LPG.
Heavier mercaptans remain in the CPC Blend crude oil.

• Key concerns associated with CPC Blend processing at high rates included
unknown levels of RSH in LPG and ability of both Butane and Kerosene Merox
units to perform at above design throughput and mercaptan levels. Due to elevated
levels of RSH in middle distillates, the kerosene Merox became a focal point in
preparation for the CPC trial.

• The decision was made to cooperate with the Merox technology provider, UOP, to
identify and develop plans to mitigate potential risks involved in CPC trial and
assess the future process modifications required for Pembroke to run higher levels
of CPC Blend.

10
 UOP Pre-Trial Recommendations
Pembroke Refinery Case Study

Predicted Performance of Kerosene Merox Unit

CPC Blend in crude slate (% vol ) 15% 25% 40%
Flow Rate (m3/h) 220 220 220
Level of mercaptan in crude kerosene, RSH-S wt ppm 150 250 400
Predicted Merox performance Mid case, RSH-S wt ppm 13 18 25
Source: UOP

Raw kerosene from CDU

ƒ Merox Plus injection

ƒ Air injections

ƒ Reactor back pressure

ƒ Hot water wash & catalyst re-impregnation

ƒ Butane Merox – no modifications required

ƒ Enhanced sampling procedure “Sweetened”

“Sweetened”kerosene
kerosene&&jet
jetfuel
fuelproducts
products
© Chevron 2005 11

• At 15% CPC Blend, the RSH concentration in raw kerosene was expected to be
between 150 and 200 ppm increasing to 400 ppm at 40%.

• UOP recommended that a catalyst activator, Merox Plus, be available for use
during the trial. Merox Plus can be continuously injected into the kerosene
upstream of the reactor at a rate of typically 25-40 wt ppm to maintain high catalyst
activity by keeping the catalyst bed clear of impurities. It is also beneficial for
processing high RSH feeds when high catalyst activity at high space velocity is
essential during an extended run.

• Higher air injection rates are required to sweeten the increased RSH concentration.
UOP recommended an upgrade to the air supply and control system.

• It is important that all of the injected air dissolves in the kerosene to prevent
channelling in the reactor. To achieve this, the back pressure on the unit should be
controlled to ensure the operating pressure at the top of the Merox reactors is at
least 1.25 bar above the pressure at which all the air dissolves.

• Both reactors were given a hot water wash and re-impregnated prior to the test.

• No modifications were recommended for the Butane Merox Unit as RSH levels in
butane stream were expected to stay within the original design limits.

• An enhanced schedule of sampling and laboratory analytical tests was prepared for
the duration of the trial to monitor product quality.

• UOP predicted that the Merox unit would reduce mercaptan sulphur content in the
treated kerosene/jet stream down to or below the 25 ppm.

11
 CPC Blend Trial Results
Pembroke Refinery Case Study

ƒ No safety or environmental incidents

ƒ Achieved 15 % CPC crude oil rate in slate

ƒ No mercaptans in CDU butane. No operational issues with butane

Merox or caustic regeneration system

ƒ Kerosene Merox reactors performed well, 200 ppm RSH kero reduced to

<25 ppm without the Merox Plus activity promoter

ƒ Higher water content (>100 ppm) observed occasionally. It did not

adversely affect jet fuel properties which remained within specifications

ƒ High RSH was registered in CDU naphtha but no constraints were

experienced during the trial due to the Unifiner performance

© Chevron 2005 12

• Seal inspections & replacements performed on the crude import system ensured
that CPC Blend test was conducted incident free (no odour was released).

• Due to crude unit constraints, the CPC Blend content of the crude slate did not
exceed 15% during the trial which limited the mercaptan content of the kerosene to
175 ppm. Therefore, it was not possible to explore the performance of the unit
under the more stringent conditions expected with 40% CPC Blend, i.e. higher
kerosene flow and 400 ppm mercaptans.

• Due to the negligible mercaptan content of the CDU butane the mercaptan removal
performance of the Butane Merox Extractor could not be assessed.

• Small RSH spikes were detected in propane but this product remained well within
specification limits.

• During the trial the water content of the kerosene was higher than usual, although
this did not result in failure to meet any of the Jet A1 specifications.

• The Unifiner was not a constraint during the test. However, a Unifiner performance
review may be required at CPC Blend feed rates above 15% due to the higher RSH
content in the naphtha stream.

12
 Recommended Modifications
Pembroke Refinery Case Study

The
The following
following modifications
modifications were
were recommended
recommended to to increase
increase CPC
CPC
Blend processing rate up to 40% of the crude slate:
Blend processing rate up to 40% of the crude slate:
ƒ The following modifications are recommended to kerosene Merox:
ƒ Installation of Merox Plus injection system
ƒ Review performance of Salt Dryer likely responsibly for higher water content in
product. The need for kerosene cooler is under consideration

ƒ Installation of the new control valve for adequate airflow control at low rates
ƒ Modification of inlet distributors of the Merox Reactor, Salt Dryers and Clay Filters
to ensure good unit performance at high throughput

ƒ Consideration should be given to CDU column traffic

ƒ Modifications of naphtha Unifiner to address higher RSH in naphtha

ƒ No modifications to butane Merox unit is recommended

ƒ Consider removal capability using molecular sieves for CDU propane

© Chevron 2005 13

• As a result of the UOP initial analysis of Merox capabilities and refinery

engineers’ internal evaluation, the following modifications have been
recommended to enable the Pembroke refinery to process CPC Blend at up to 40%
rate.

• Although Merox Plus was largely unutilized during the trial due to low CPC Blend
processing rate, its usage is recommended to boost Merox unit performance at high
throughput and RSH rates.

• The reason for the high water content is likely to be the poor performance of the
Salt Filters. The installation of a kerosene cooler upstream of the water wash, to
reduce the solubility of water in the kerosene, may not be necessary if the salt
filters are operating satisfactorily.

• Modifications to the CDU pump around system and column re-traying is being
considered to increase CPC Blend processing rates.

• The naphtha Unifiner can be a bottleneck at higher processing rates and should be
addressed.

• On the Butane Merox side, the Extractor was capable of handling butane flow rates
without caustic carry over, which means there is no urgency to modify the
Extractor trays to reduce the velocity of butane through the perforations.

• Although the trial did not suggest there would be an increased RSH in the propane
stream, potential problems can be addressed by installing molecular sieves if
necessary.

13
 Way Forward
Pembroke Refinery Case Study

ƒ CPC Blend trial was successful

ƒ Pembroke proved its ability to process the CPC Blend as a minority

crude (15-20% rate) on a regular basis

ƒ Plan has been developed and required modifications are being

implemented to increase CPC Blend processing rate up to 40%

ƒ A program of technical assistance and operational excellence is being

developed to share the knowledge with other refineries

© Chevron 2005 14

• The CPC Blend trial was successful and proved the Pembroke refinery’s ability to
process CPC Blend on a regular basis at low rates of 15% to 20%.

• A Pembroke/UOP joint engineering team has identified modification required to

process CPC Blend at up to 40% of crude slate. These modifications are currently
being implemented.

• A program of technical assistance and operational excellence is being developed to

share the knowledge with other refineries.

14
 Contact Details

Commercial Issues Technical Issues

Alex Kokashinsky Andrew Cole

Commercial Adviser Process Engineer (Merox)
Chevron Global Supply & Trading Chevron
London Office Pembroke Refinery

t.+44 207 719-3116 t.+44 164 664-9499

f.+44 207 719-5155 f.+44 164 664-1242
kokasal@chevron.com ColeAL@chevron.com

Corwin Rose Steve Hull

Commercial Manager Process Engineer (High Acid Crudes)
Chevron Overseas Petroleum Chevron
London Office Pembroke Refinery

t.+44-207-719-3539 t.+44 164 664-9399

f.+44 207 719-5522 f.+44 164 664-1242
corw@chevron.com HullSJ@chevron.com

© Chevron 2005 15

• For further details on the Commercial and Technical aspects of this Case Study,
please contact the above named individuals - many of which are in attendance at
this conference.

15
 Appendix
High Acid Crude Oil Processing Guidelines

Conventional Wisdom / Correlations

ƒ Processing guidelines

ƒ Whole crude oil max TAN – 0.5mg KOH/g; Crude oil with higher TAN can be

run with inhibitors and monitoring

ƒ Side cut max TAN – 1.5mg KOH/g; Usually, VGO is the highest

ƒ TAN alone is not reliable indication of corrosion potential

ƒ Different types of naphthenic acid effect corrosion differently

© Chevron 2005 16

16
 Appendix
High Acid Crude Oil Processing Guidelines

Three Traditional Corrosion Prevention Methods

ƒ Blending with low acid crude oils – (most common way)
ƒ Typically, run high TAN 10-30% with low TAN crude oil
ƒ Metallurgy/Tankage can become limiting
ƒ Crude compatibility needs evaluation (e.g. asphaltenes)

ƒ Use of corrosion inhibitors and monitoring

ƒ Generally used until alloy upgrades can be made
ƒ Used if high acid crude attack is limited and can be monitored
ƒ Used when blend is moderately corrosive
ƒ For more information – contact refinery chemicals companies

ƒ Metallurgy upgrade to 316 and 317 SS by welding liner material into

crude unit and side cut draws

© Chevron 2005 17

17