OPERATING MANUAL VOLUME 13 LIGHT NAPHTA ISOMERIZATION UNIT

PROCESS DATA SHEET
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PDS94 - Rev. 4 - ANG - XL97 H:\projet\8475M-DQR-POC\08-Process\Operating Manuals\operating manual - DQR\ISOM\[8474L-023-ML-001-A.xls]PAGE A PD094A14
ISSUE FOR REVIEW

Description
Op. Center JOB N
o
.
Op. Center Doc. N
o
.
27-JUL-07
Date
DD-MMM-YY
C. VERDON
Written by
J-P. BINET
Checked by
R. LEFEBVRE
Approved by
Ch 11
Ch 12
Ch 13
Ch 14
Ch 7
Ch 8
Ch 9
Ch 10
Ch 3
Ch 4
Ch 5
Ch 6
Ch 1
Ch 2

023
PENEX
A
A
PENEX UNIT (023)
OPERATING MANUAL
PETROVIETNAM
DUNG QUAT
VIETNAM
A8474L-023 ML 001
FEED Doc. N
o
.
DOCUMENT CLASS X


VIETNAM OIL AND GAS CORPORATION
(PETROVIETNAM)

DUNG QUAT REFINERY




OPERATING MANUAL


VOLUME 13

LIGHT NAPHTA
ISOMERIZATION UNIT


UNIT 023

BOOK 1/2


Rev. 0





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CONTENTS
CHAPTER 1 BASIS OF DESIGN
1. DUTY OF THE PLANT

2. ENVIRONMENTAL CONDITIONS
3. FEEDSTOCKS AND PRODUCTS SPECIFICATIONS
4. OVERALL MATERIAL BALANCE OF THE UNIT
5. BATTERY LIMIT CONDITIONS
6. DESIGN FEATURES
7. GAS AND LIQUID EFFLUENTS

CHAPTER 2 PROCESS DESCRIPTION
1. PROCESS THEORY
2. DESCRIPTION OF FLOW

CHAPTER 3 DESCRIPTION OF UNIT CONTROL
1. DESCRIPTION OF FLOW WITH CONTROLS
2. OPERATING CONDITIONS
3. PROCESS VARIABLES
4. INTER-UNIT CONTROL SCHEME
5. UNINTERRUPTIBLE POWER SUPPLY (UPS)
6. COMPLEX CONTROL DESCRIPTION

CHAPTER 4 UILITY, CHEMICAL AND CATALYST REQUIREMENTS
1. UTILITIES
2. CHEMICALS CONSUMPTION

CHAPTER 5 PREPARATION FOR INITIAL START-UP
1. PLANT CHECK-OUT
2. LINE FLUSHING
3. WATER CIRCULATION
4. LEAK TESTING
5. HEATER DRY-OUT
6. LOADING OF METHANATOR, DRIERS, SCRUBBER AND REACTORS

7. CHEMICAL CLEANING

CHAPTER 6 INITIAL AND NORMAL START-UP
1. SUMMARY OF START-UP
2. PURGING AND GAS BLANKETING
3. METHANATOR START-UP
4. HYDROCARBON CIRCULATION AND INITIAL DRYDOWN
5. ACIDIZING AND FINAL DRYDOWN
6. CATALYST LOADING
7. INITIAL START-UP
8. NORMAL START-UP
9. DEISOHEXANIZER START-UP
10. NORMAL OPERATION

CHAPTER 7 NORMAL SHUTDOWN
1. NORMAL SHUTDOWN PROCEDURES
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2. CATALYST UNLOADING AND HANDLING PROCEDURES
3. SPECIAL PROCEDURES

CHAPTER 8 EMERGENCY SHUTDOWN PROCEDURES
1. INTRODUCTION

2. EMERGENCY FUNCTIONS PHILOSOPHY
3. PROCESS FAILURES
4. UTILITY FAILURES
5. MAJOR UPSETS

CHAPTER 9 SAFETY EQUIPMENT AND PROCEDURES
1. PRESSURE SAFETY DEVICES
2. ALARM SETTINGS
3. TRIP SETTINGS
4. TRIP SYSTEM CHART
5. CAUSE AND EFFECT DIAGRAM
6. MATERIAL HAZARD DATA SHEETS
7. SAFEGUARDING MEMORANDUM

CHAPTER 10 INSTRUMENT DATA
1. CONTROL VALVES AND INSTRUMENTS
2. ORIFICE PLATES

CHAPTER 11 SUMMARY OF MAJOR EQUIPMENT
1. EQUIPMENT LIST
2. LARGE ROTATING EQUIPMENTS
3. HEATERS
4. OTHER VENDOR INFORMATION

CHAPTER 12 ANALYSIS
1. INTRODUCTION
2. SAMPLING SCHEDULES / APPROVED TEST METHODS
3. ANALYTICAL METHODS
4. ON-LINE ANALYZERS

CHAPTER 13 PROCESS CONTROL
1. DISTRIBUTED SYSTEM CONTROL (DCS)

CHAPTER 14 DRAWINGS
1. PLOT PLAN AND HAZARDOUS CLASSIFICATION
2. PROCESS FLOW DIAGRAMS AND MATERIAL SELECTION DIAGRAMS
3. PIPING AND INSTRUENTATION DIAGRAMS
4. OTHER DRAWINGS

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CHAPTER 1
BASIS OF DESIGN
CONTENTS
1. DUTY OF THE PLANT
1.1 LICENSOR
1.2 FUNCTION OF THE UNIT
2. ENVIRONMENTAL CONDITIONS
2.1 AIR TEMPERATURE
2.2 RELATIVE HUMIDITY
2.3 RAINFALL
2.4 SNOWFALL

2.5 AIR BAROMETRIC PRESSURE
2.6 WIND
2.7 ATMOSPHERE
2.8 MISCELLANEOUS DATA
3. FEEDSTOCKS AND PRODUCTS SPECIFICATIONS
3.1 FEEDS CHARACTERISTICS
3.1.1 HYDROTREATED LIGHT NAPHTHA
3.1.2 MAKEUP GAS
3.2 PRODUCTS SPECIFICATIONS
3.2.1 ISOMERATE
3.2.2 NET GAS
4. OVERALL MATERIAL BALANCE OF THE UNIT
4.1 PROCESS INLET
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4.2 PROCESS OUTLET
5. BATTERY LIMIT CONDITIONS
5.1 FEEDSTOCKS BATTERY LIMIT CONDITIONS
5.2 PRODUCTS BATTERY LIMIT CONDITIONS
5.3 UTILITIES BATTERY LIMIT CONDITIONS
6. DESIGN FEATURES
6.1 EQUIPMENT OUTSIDE LICENSOR SCOPE
6.2 MANDATORY SUPPLY

6.2.1 SULFUR ABSORPTION AND METHANATION CATALYSTS
6.2.2 ISOMERIZATION REACTOR CATALYST
6.2.3 MOLECULAR SIEVES
6.2.4 DRCS
7. GAS AND LIQUID EFFLUENTS

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1. DUTY OF THE PLANT
1.1 LICENSOR
The Penex / DIH Process (Unit 023) is based on the UOP (Universal Oil Products)
process. The Licensor has issued the following documents:
♦ UOP Project Specification (Project 928504).
♦ UOP Penex Process Hydrogen Once Through: General Operating Manual.
♦ UOP Deisohexanizer: General Operating Manual.
♦ UOP Methanator Information (Additional section of the Penex Process Hydrogen
Once Through General Operating Manual).

1.2 FUNCTION OF THE UNIT
The function of the Penex / DIH Unit is to process straight run light naphtha from the
overhead of the Naphtha Splitter column T-1202 (Unit 012) to produce a high octane
isomerate naphtha product. The light straight run naphtha is derived from either 100%
Bach Ho Crude or Mixed Crude (85% Bach Ho / 15% Arabian Light). The Penex unit is

designed for a capacity of 231 613 metric tonnes per year (equivalent to 6500 BPSD).
The UOP Penex Process is a continuous catalytic isomerization of pentanes, hexanes
and mixtures thereof, based on an equilibrium reaction. The reactions take place in a
hydrogen atmosphere, over a fixed bed of catalyst and at operating conditions, which
promote isomerization and minimize hydrocracking. This product is a mixture of iso-
paraffins with a high octane number.
The process is simple and straightforward in design and operation and trouble-free in
performance permitting a minimum of staffing and supervision. Operating conditions are
not severe as reflected by moderate operating pressure, low temperature, high catalyst
space velocity and low hydrogen partial pressure requirements.
Except for normal hydrotreating, the PENEX Process requires neither special feed
pretreatment nor especially sharp prefractionation for removal of C
6
cyclics or C
7
+
. Penex
affords the refiner considerable flexibility in the choice of feedstocks both at the time of
design or after the unit is constructed.
The major elements of the Penex / DIH Unit are the liquid feed and make-up gas driers,
the methanator, the feed surge drum, the reactors and associated heater and
exchangers, the product stabilizer, the net gas scrubber and the deisohexanizer.
Although not essential to the success of the process, the Penex system will normally
employ two reactors in a series flow configuration with the total required catalyst loading
being equally distributed between the vessels. Valving and piping are provided which
permit reversal of the processing positions of the vessels and the isolation of either for
partial catalyst replacement. With time, the Penex catalyst will become deactivated by
water, not hydrocarbon. Because the water deactivation proceeds as a sharp front,
which moves down the bed in a piston-like fashion, catalyst downstream of the front
remains unaffected. When catalyst in the lead reactor is spent, the reactor is taken off

line for reloading. During the short period of time the reactor is out of service, the second
reactor is capable of maintaining continuous operation at design throughput and yield;
conversion is moderately lower. After catalyst reloading is completed, the processing
positions of the two reactors may be reversed.
The two reactor design permits essentially 100% unit onstream efficiency and reduces
catalyst consumption costs by making partial catalyst replacements practical. It also
permits the unit to be designed for a smaller catalyst inventory (higher space velocity)
thus reducing catalyst capital requirements. Isomerization and benzene hydrogenation
reactions are both exothermic and the temperature increases across the reactor.
Equilibrium requires that the outlet temperature be as low as the activity of the catalyst
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permits. With a single reactor, this would lead to a low inlet temperature and low
isomerization rates in part of the catalyst bed. The two reactor system permits the
imposition of an inverse temperature gradient by cooling between reactors through
exchange against cold feed. The first reactor may, therefore, be operated at a higher
temperature and achieve a higher reaction rate. This reduces the inventory of catalyst
and the reactor size required. Most of the isomerization is thus accomplished at high rate
in the first reactor and the final portion is performed at a lower temperature to take
advantage of the more favorable equilibrium.
Not all catalysts are suitable for application of the inverse temperature gradient principle.
Some might coke or sludge if operated at a higher inlet temperature, or else they might
promote excessive hydrocracking and yield loss. Since the Penex catalyst does neither

of these, the inverse gradient can be applied to economic advantage.
Chloride promoter (perchloroethylene) is added continuously with the feed and is
converted to hydrogen chloride in the reactor. Since the catalyst functions with very small
amounts of promoter (measured in parts per million), it is not necessary to provide
separate equipment for recovery and re-use of hydrogen chloride. It is permitted to leave
the unit by way of the stabilizer gas. The quantity of stabilizer gas is small, due to the
selective nature of the catalyst, which permits very little hydrocracking of the
pentane/hexane charge to take place.
To protect the catalyst, the liquid feed is first charged to the feed dryers and then to the
charge surge drum. Hydrogen make-up gas is sent to a methanator to remove trace
levels of CO, CO
2
and H
2
S and then onto the make-up gas dryers prior to be mixed with
the combined feed from the charge surge drum and sent to the reactors.
The effluent from the reactor is charged to a stabilizer to remove the residual hydrogen
from the reaction and the light gases (C
1
through C
4
) introduced with the make-up gas
and produced in the reactor as a result of cracking. The stabilizer gas is scrubbed for
hydrogen chloride removal before entering the refinery fuel gas system (Unit 037).
The catalyst itself is non-corrosive in the plant and, despite the presence of small
amounts of hydrogen chloride during operation, the dryness of the system permits
construction of carbon steel.
Bottom stream from the stabilizer is sent to the deisohexanizer (DIH) column. The DIH
primarily separates C
5

, 2,2-dimethylbutane and 2,3-dimethylbutane from the other C
6

isomers and heavier components of the isomerate. The benefit of the addition of a DIH
column is to upgrade to a product with an octane value of 88.0 - 90.0 RONC. Compared
to a maximum research octane number of approximately 84.0 RONC for a hydrocarbon
once-through operation, this is a significant increase.
More benefits from a DIH column are derived as the C
5
/C
6
ratio of the fresh charge
decreases since the nC
5
is not recycled back to the reactor section for further
isomerization.
The DIH overhead product, composed primarily of C
5
's and dimethylbutanes, is sent to
storage for gasoline blending. The bottoms, flow-controlled at a small rate, are also
typically sent to storage with the DIH overhead product; however, the bottoms should be
evaluated as potential reformer feedstock as well. The bottoms draw is necessary to
avoid a build-up of heavies in the reactor section charge.
The DIH side draw, composed primarily of methylpentanes, some dimethylbutanes and
nC
6
, is recycled back on flow control to the isomerization unit upstream of the reactors.
Hereafter are supplied the following documents:
 Diagrams showing all process and utilities connections with other units
 Overall block flow diagram of the Refinery

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PENEX / DIH
PROCESS
(UNIT 023)
Isomerate to TK-5106 A/B
Net gas to FG (unit 037)
Light naphtha from unit 012
Make-up gas from unit 012
Potable water
Plant Air
Instrument air
Refinery Nitrogen
Cold BFW
Service water
CW supply
LP steam
MP steam
20°Be Caustic from unit 039
Flare to unit 057
CW return
LP condensate
MP condensate
Oily water







PENEX / DIH

PROCESS
(UNIT 023)

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2. ENVIRONMENTAL CONDITIONS
2.1 AIR TEMPERATURE
a. Maximum recorded 41.4 °C
b. Minimum recorded 12.4 °C
c. Maximum monthly average 34.4 °C
d. Minimum monthly average 18.9 °C
e. Design maximum 36.0 °C
f. Design minimum 16.0°C
2.2 RELATIVE HUMIDITY
a. Maximum monthly average 89%
b. Minimum monthly average 80%
c. Average monthly humidity 85%
d. Design maximum 100%
e. Design minimum 40%
2.3 RAINFALL
a. Maximum recorded annual 3052 mm
b. Minimum recorded annual 1374 mm
c. Average annual 2268 mm

d. Maximum recorded in 24 hours 525 mm
e. Maximum rainfall intensity 40 mm for 10 min period
60 mm for 30 min period
108.1mm for 60 min period
2.4 SNOWFALL
Not applicable
2.5 AIR BAROMETRIC PRESSURE
a. Maximum 1023.6 mbar
b. Minimum 988.8 mbar
c. Average 1009 mbar
d. Design 1013 mbar
2.6 WIND
a. Average velocity 3.2 m/s
b. Maximum hourly velocity 42 m/s

Direction
% of time for each Quadrant
No wind 43.8
N/NE 9.7/6.2
W/NW 4.1/14.3
E/SE 12.8/6.7
S/SW 1.1/1.0

The maximum velocity over a 2 minutes is 41.6 m/s for a return period of 50 years.
The maximum velocity over a 2 minutes is 32.7 m/s for a return period of 20 years

2.7 ATMOSPHERE
a. Extreme moisture - tropical climate
b. Marine exposure - salt spray
c. Sand storms - not applicable

d. Copper-attacking fumes - sulphur
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e. Exposure to conductive or corrosive dusts (carbon, iron oxide, ammonium nitrates or
phosphates, etc): NO
f. Exposure to corrosive agents (nitric or sulphuric acids, chlorine, caustic, etc): NO
g. Exposure to other pollutants originating from surrounding industrial plant: YES
2.8 MISCELLANEOUS DATA
a. Frost Level Not applicable
b. Typhoon frequency 2 to 3 per year
c. Thunderstorm frequency 102 storm days per year
d. Temperature inversion occurrence Not applicable
e. Earthquakes to be taken into account and design shall be as per code UBC, zone
2
f. The site is subjected to possible flood condition
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3. FEEDSTOCKS AND PRODUCTS SPECIFICATIONS
3.1 FEEDS CHARACTERISTICS
3.1.1 HYDROTREATED LIGHT NAPHTHA
The Penex / DIH unit is designed to process straight run hydrotreated light naphtha,
coming from Naphtha hydrotreating unit (Unit 012), derived from 100% Bach Ho or
Mixed crude oils (85% Bach Ho and 15% Dubai crude) at a design capacity of 6500
BPSD.
Following UOP’s evaluation of the full range naphtha for the 100% Bach Ho case and
the Mixed case, the naphtha composition has been determined to be identical for both
cases except for the higher sulfur in the Mixed case. Accordingly only a single design
case based on 100% Bach Ho with a maximum sulfur level content of 100 ppm wt shall
be used as the basis of design for the NHT/Penex-DIH and the CCR Paltformer
Complex. The NHT/Penex-DIH and the CCR Paltformer shall be capable of processing
both cases.
The feed definition for the Penex / DIH unit has the following properties:

Feed rate = 6500 BPSD.
Turndown = 3250 BPSD.

Pro
p
ert
y

V
alue Test Method
Densit
y
at 15°C 0.674

A
STM D 4052
Com
p
osition
,
mole%
UOP 551
N-Butane 1.16
Iso-Butane 0.12
Iso-Pentane 11.34
N-Pentane 19.00
C
y
clo
p
entane 0.12
2,2-Dimeth
y
lbutane 0.74
2,3-Dimeth
y
lbutane 1.62
2-Meth
y
l
p
entane 11.72
3-Meth
y

l
p
entane 6.34
N-Hexane 25.86

Total C
5
, wt. % 30.5 min.
Benzene, wt. % 6.3 max.
C
7
+
, wt. % 3.8 max.
Total C
6
Na
p
htenes, wt. % 11.9 max.

Meth
y
lc
y
clo
p
entane 6.09
C
y
clohexane 5.81
Benzene 6.30

N-He
p
tane 3.78
Water Saturated at desi
g
n tem
p
erature UOP 481
Mol. Wei
g
ht, k
g
/k
g
mole 80.48
Co
pp
er, wt.
pp
b 20 max. UOP 144
Lead, wt.
pp
b 10 max. UOP 350
A
rsenic, wt.
pp
b 1 max. UOP 296
Fluorides Not Detectable UOP 619
Bromine Number 4.0 max. UOP 304
Chlorides, wt.

pp
m 0.5 max. UOP 395
Total Sulfur, wt.
pp
m 0.1 max.
A
STM D-4045
Total Nitro
g
en, wt.
pp
m 0.1 max.
A
STM D-4629
Total Oxygenates (excluding
water
),
wt.
pp
m
0.5 max.
Method based on
sus
p
ected com
p
ound

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3.1.2 MAKEUP GAS
Make-up gas for the Penex / DIH Unit is delivered from the 3
rd
stage discharge of the
make-up gas multi-stage compressors C-1202A/B/C (Unit 012) at a pressure of 42.3
kg/cm
2
(g). It is a product of CCR platforming unit (Unit 013).

The composition of hydrogen is the following in normal operation:

Compound
Make-up Hydrogen
mole %
H2 93.3
Methane 2.5
Ethane 2.4
Propane 1.4
i Butane 0.1
n Butane 0.1
i Pentane 0.04
n Pentane 0.02
C

6
+ 0.04

3.2 PRODUCTS SPECIFICATIONS
3.2.1 ISOMERATE
For the total refinery, two design cases are specified: a Design case corresponding to
6500 BPSD (Light Naphtha with cut points C
5
- 82°C / high benzene feed) and an
Alternate case corresponding to 5336 BPSD (Light Naphtha with cut points C
5
- 70°C /
low benzene feed). The isomerate properties depend on the operating case and on the
reactors catalyst level of activation.
Hereafter are given the composition of the isomerate obtained for each case at Start Of
Run (fresh catalyst) and End Of Run (spent catalyst).


Property Value

C
5
+
Product Yield at Start-of-Run, 95.2
(wt. % Fresh Feed, minimum)
C
5
+
RONC 87
C

5
+
MONC 85
RVP, kg/cm² 0.82
Benzene, vol % 0
Aromatics, vol % 0
Olefins, vol % 0
Sulfur, wt-ppm 1 max.
Nitrogen, wt-ppm 1 max.
Oxygenates, wt-ppm 1 max.





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Design Case Alternate Case
PROPERTY
SOR EOR SOR EOR
Density at 15°C 0.656 0.656 0.647 0.648
Composition, kmol/h
Propane Trace Trace Trace Trace

Iso-Butane 0.79 0.58 0.20 0.14
N-Butane 1.67 1.35 0.73 0.61
Iso-Pentane 108.87 104.52 99.34 95.85
N-Pentane 33.69 38.76 28.49 32.65
Cyclopentane 0.33 0.35 0.33 0.35
2,2 Dimethylbutane 104.08 79.78 110.00 95.94
2,3 Dimethylbutane 18.83 22.92 10.90 14.19
2-Methyl pentane 31.44 46.70 16.26 24.65
3-Methyl pentane 5.18 9.13 2.63 4.56
N-Hexane 0.45 0.77 0.30 0.47
Methylcyclopentane 0.44 0.84 0.13 0.23
Cyclohexane 3.28 3.00 1.36 1.27
Benzene Trace Trace Trace Trace
2-Methylhexane 0.20 0.26 Trace Trace
N-Heptane 0.16 0.26 Trace Trace
Methylcyclohexane 25.39 22.24 8.21 7.74


3.2.2 NET GAS
A net gas stream will be produced from the overhead of the Stabilizer and will be routed via
a caustic scrubber for hydrogen chloride removal before being sent to Fuel Gas Unit (Unit
037).

The composition of this gas is given hereafter for the different cases:


Design Case Alternate Case
Compound
SOR EOR SOR EOR
H

2
O, %mol 0.9 0.9 0.9 0.9
H
2
, %mol 41.6 43.3 52.9 55.0
Methane, %mol 8.0 7.9 6.8 6.7
Ethane, %mol 7.1 6.6 6.3 5.7
Propane, %mol 14.9 14.3 5.8 5.6
Iso-Butane, %mol 20.0 18.7 15.4 13.4
N-Butane, %mol 7.1 7.7 10.5 11.0
Iso-Pentane, %mol 0.4 0.6 1.3 1.7
N-Pentane, %mol 0.0 0.0 0.1 0.1


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4. OVERALL MATERIAL BALANCE OF THE UNIT
4.1 PROCESS INLET

4.2 PROCESS OUTLET

Design Case Alternate Case

SOR EOR SOR EOR
Hydrotreated light naphtha, kg/h 28960 28960 23242 23242
Make-up gas, kg/h 609 598 336 330
Chloride, kg/h 9 9 7 8
TOTAL 29578 29567 23585 23580
Design Case Alternate Case


SOR EOR SOR EOR
Isomerate, kg/h 27617 27724 22436 22510
Net gas, kg/h 1956 1838 1146 1063
TOTAL 29573 29562 23582 23573
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5. BATTERY LIMIT CONDITIONS
The total refinery site is divided in blocks. Every block contains one or more units. The
isomerization unit is situated together with NHT and CCR units (012 and 013). Because
of this construction there are two types of battery limits: battery limits for units and battery
limits for blocks. For feedstocks and products the unit battery limit conditions for the
process streams are given. For utilities the block battery limits are given.
All the process lines entering/leaving the considered block are represented on PID
8474L-012-PID-0021-001 whereas the process lines leaving NHT/CCR or PENEX units
but not leaving the block are represented on PID 8474L-012-PID-0021-002. Utility lines

are represented on utility PIDs.

5.1 FEEDSTOCKS BATTERY LIMIT CONDITIONS
DESIGN CONDITIONS AT
B/L
OPERATING CONDITIONS
AT B/L

ORIGIN
PRESSURE (1)
Kg/cm2 (g)
TEMPERATURE
(°C)
PRESSURE (1)
Kg/cm2 (g)
TEMPERATURE
(°C)
Hydrotreated
light naphtha
Unit 012 16.0 120 7.0 38
Makeup gas Unit 012 48.0 160 42.3 38


5.2 PRODUCTS BATTERY LIMIT CONDITIONS
DESIGN CONDITIONS AT
B/L
OPERATING CONDITIONS
AT B/L

DESTINATION

PRESSURE (1)
Kg/cm2 (g)
TEMPERATURE
(°C)
PRESSURE (1)
Kg/cm2 (g)
TEMPERATURE
(°C)
Isomerate U051 16.0 65 3.5 37
Net gas U037 (Fuel Gas) 14.5 160 4.7 38

Note: (1) At grade – Unit 023 Battery Limit elevation is 6 m.

5.3 UTILITIES BATTERY LIMIT CONDITIONS

DESIGN CONDITIONS AT
B/L
OPERATING CONDITIONS
AT B/L

DESTINATION /
ORIGIN
PRESSURE (1)
Kg/cm2 (g)
TEMPERATURE
(°C)
PRESSURE (1)
Kg/cm2 (g)
TEMPERATURE
(°C)

UTILITIES SUPPLY
MP steam OSBL 16.8 320 14.1 (3) 250
LP steam OSBL 6.3 230 3.6 (3) 160
Cold Boiler
Feedwater
OSBL 16.3 115 4 (2) 60
Instrument Air OSBL 10.5 65 7.5 (2) 35
Refinery
Nitrogen
OSBL 11.7 65 7 (3) 30
Cooling Water OSBL 9.2 70 5.2 (3) 32
Plant Air OSBL 10.5 65 7.5 (2) 35
Service Water OSBL 14.2 60 5 (2) 30
Potable Water OSBL 5.5 60 2.5 (2) 30
20° Be Caustic OSBL 5.5 70 1.5 (2) 40
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UTILITIES RETURN
MP Condensate OSBL 16.8 320 7.5 (3) 170
LP condensate OSBL 6.3 230 2 (3) 133
Cooling Water OSBL 9.2 70 2.2 (3) 47
Oily Water OSBL 4.7 65 3.5 (3) 36
Flare OSBL 3.5 210 0.2 (1) 38

Notes: (1) At grade – Units 012/013/023 Battery Limit elevation is 15 m.
(2) At grade – Units 012/013/023 Battery Limit elevation is 12 m.
(3) At grade – Units 012/013/023 Battery Limit elevation is 9 m.
(4) At grade – Units 012/013/023 Battery Limit elevation is 6 m.

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6. DESIGN FEATURES
6.1 EQUIPMENT OUTSIDE LICENSOR SCOPE
Neutralization of spent caustic

The net gas stream produced from the overhead of the stabilizer is routed to the net gas
scrubber (T-2302) for hydrogen chloride removal before being sent to Fuel Gas (Unit 037).
This is accomplished by contacting the rising acidic gases with a 10 wt% caustic solution.
The caustic is to be changed out before it falls below 2 wt%, therefore, periodically (once a
week), a portion of caustic is withdrawn to a degassing drum (D-2305) and sent by gravity to
a Neutralization Pit TK-2399. This stream contains NaClO which needs to be neutralized.
This is done with sulfuric acid on pH control, which acts as an oxygen scavenger. The
neutralized spent caustic is then routed to the oily water sewer by means of the
Neutralization Pit Eductor (J-2399).
The Neutralization Pit Eductor (J-2399) and the Neutralization Pit (TK-2399) are part of the
Isomerization Unit but are outside Licensor scope.

6.2 MANDATORY SUPPLY
6.2.1 SULFUR ABSORPTION AND METHANATION CATALYSTS
Catalyst type required for sulphur absorption in Methanator vessel (R-2301) is Puraspec
2010 from Johnson Matthey. This catalyst has a density of 1155 kg/m
3
and the installed
volume is of 0.43 m
3
. It shall be replaced approximately every 3 years.
Catalyst type required for methanation reaction in Methanator vessel (R-2301) is
Puraspec 2443 from Johnson Matthey. This catalyst has a density of 1105 kg/m
3
and the
installed volume is of 2.21 m
3
. It shall be replaced approximately every 3 years.
Sulfur absorption and methanation catalysts are sock-loaded into the methanator.
MSDS will be in the attachments.

6.2.2 ISOMERIZATION REACTOR CATALYST
Isomerization catalysts required are I-8 Plus and I-82 Penex Catalysts from UOP. They
are amorphous, chlorided alumina, light paraffin isomerisation catalysts containing
platinum, optimized for use in Penex units. They selectively convert normal butane,
pentane and hexane to high octane branched hydrocarbons. In addition to isomerisation
of paraffins, they also saturate benzene.
Initially lead reactor is loaded with I-8 Plus catalyst and lag reactor with I-82 catalyst.
These catalysts have a density of 885 kg/m
3
and the installed volume is of 24.7 m

3
per
reactor. They shall be replaced approximately every 6 years.
The I-8 Plus/I-82 Penex catalysts are dense loaded into the reactors.
MSDS will be in the attachments

6.2.3 MOLECULAR SIEVES
Molecular sieves required for Makeup Gas Driers (DR-2301/2302) shall be Molsiv
Adsorbent type PDG-418 from UOP. Sieves density is of 660 kg/m
3
and the installed
volume is of 1.97 m
3
per drier. Molecular sieves shall be replaced approximately every 3
years.
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Molecular sieves required for Feed Driers (DR-2303/2304) shall be Molsiv Adsorbent
type HPG-250 from UOP. Sieves density is 640 kg/m3 and the installed volume is of 5.90
m3 per drier. Molecular sieves shall be replaced approximately every 3 years.
Molecular sieves are normally sock-loaded into the driers.
MSDS will be in the attachments

6.2.4 DRCS
The selected UOP Drier Regeneration Control System (DRCS) is mandatory for the
Makeup Gas Driers and the Feed Driers.
For the regeneration operation of these driers, refer to Chapter 6 (6.7. Normal operation).

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7. GAS AND LIQUID EFFLUENTS

Refer to attached document: “Effluent Summary Table” – 8474L-200-NM-6200-002.
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CHAPTER 2
DESCRIPTION OF PROCESS

CONTENTS
1. PROCESS THEORY
1.1 PROCESS PRINCIPLES
1.2 REACTION MECHANISMS
1.2.1 FRIEDEL-CRAFTS CATALYST
1.2.2 DUAL-FUNCTION HYDRO-ISOMERIZATION CATALYST
1.3 HISTORY OF CATALYST
1.3.1 FRIEDEL-CRAFTS TYPE CATALYST
1.3.2 HYDRO-ISOMERIZATION CATALYSTS ABOVE 200°C
1.3.3 HYDRO-ISOMERIZATION CATALYSTS BELOW 200°C
1.4 OTHER REACTIONS
1.4.1 NAPHTENE RING OPENING
1.4.2 NAPHTENE ISOMERIZATION
1.4.3 BENZENE SATURATION
1.4.4 HYDROCRACKING
1.5 METHANATION
1.6 ACIDIZING
1.7 CHLORIDE PROMOTER
1.8 CAUSTIC SCRUBBING
1.9 DE-ISOHEXANIZER (DIH): THEORY OF FRACTIONATION
2. DESCRIPTION OF FLOW
2.1 FEED DRIERS (DR-2303/2304) (P&ID 023-PID-0021-013)
2.2 METHANATOR (R-2301) (P&ID 023-PID-0021-010)
2.3 MAKE-UP GAS DRIERS (DR-2301/2302) (P&ID 023-PID-0021-011)
2.4 REGENERANT VAPORIZER (E-2305) (P&ID 023-PID-0021-012)
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2.5 REGENERANT SUPERHEATER (A-2301) (P&ID 023-PID-0021-012)
2.6 FEED SURGE DRUM (D-2301) (P&ID 023-PID-0021-015)
2.7 REACTOR EXCHANGER CIRCUIT (P&IDs 023-PID-0021-015 to 018)
2.8 ISOMERIZATION REACTORS (R-2302/2303) (P&ID 023-PID-0021-019)
2.9 STABILIZER (T-2301) (P&IDs 023-PID-0021-020/021)
2.10 NET GAS SCRUBBER (T-2302) (P&IDs 023-PID-0021-022 to 026)
2.11 DE-ISOHEXANIZER (T-2303) (P&IDs 023-PID-0021-026 to 030)

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1. PROCESS THEORY
1.1 PROCESS PRINCIPLES
The principle of the process is the isomerization reaction, which takes place in the
reactors. It is an equilibrium reaction and converts normal paraffins to isoparaffins, which
have a higher octane number.
Reaction takes place on a fixed bed catalyst, containing a supported noble metal and a
component to provide acidity. The reaction is operated in a hydrogen atmosphere and
employs perchloroethylene as a catalyst promoter, which is injected with the feed in the
range of concentration of 150 parts per million weight. The catalyst requires a dry, low

sulfur feedstock. Hydrocracking to light gases is generally slight.
The C
5
/C
6
paraffin isomerization reactions, which occur in the Unit 023, are shown
below. The octane numbers presented in this section are for pure components:


NORMAL HEXANE 2 METHYL PENTANE
CH
3

CH
3
- CH
2
- CH
2
- CH
2
- CH
2
- CH
3
⇔ CH
3
- CH - CH
2
- CH

2
- CH
3

24.8 RON-O 73.4 RON-O

3 METHYL PENTANE
CH
3

CH
3
- CH
2
- CH
2
- CH
2
- CH
2
- CH
3
⇔ CH
3
- CH
2
- CH - CH
2
- CH
3

74.5 RON-O




2-2 DIMETHYL BUTANE
CH
3

CH
3
- CH
2
- CH
2
- CH
2
- CH
2
- CH
3
⇔ CH
3
- C - CH
2
- CH
3

CH
3
91.8 RON-O

2-3 DIMETHYL BUTANE
CH
3

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CH
3
- CH
2
- CH
2
- CH
2
- CH
2
- CH
3

⇔ CH
3
- CH - CH - CH
3


CH
3

104.3 RON-O

NORMAL PENTANE ISO PENTANE
CH
3


CH
3
- CH
2
- CH
2
- CH
2
- CH
3
⇔ CH
3
- CH - CH
2

- CH
3

61.8 RON-O 93.0 RON-O

2 METHYL PENTANE 2-2 DIMETHYL BUTANE
CH
3
CH
3


CH
3
- CH - CH
2
- CH
2
- CH
3
⇔ CH
3
- C - CH
2
- CH
3


CH
3

2-3 DIMETHYL BUTANE
CH
3
CH
3


CH
3
- CH - CH
2
- CH
2
- CH
3
⇔ CH
3
- CH - CH - CH
3


CH
3




3 METHYL PENTANE 2-2 DIMETHYL BUTANE

CH
3
CH
3

CH
3
- CH
2
- CH - CH
2
- CH
3
⇔ CH
3
- C - CH
2
- CH
3


CH
3

In the DIH, fractionation of the product occurs. In the following paragraphs, first, the
theory of the reaction and the history of the catalyst will be discussed, then the theory of
fractionation.
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1.2 REACTION MECHANISMS
Paraffin isomerization catalysts fall mainly into either of two principal categories:
1. Those based on Friedel-Crafts catalysts as classically typified by aluminum
chloride/hydrogen chloride.
2. Dual-function hydro-isomerization catalysts.
The catalyst used in this isomerization unit is of the second category. For completeness
both mechanisms will be discussed.
1.2.1 FRIEDEL-CRAFTS CATALYST
No attempt is made to present a discussion of mechanisms of a degree of sophistication
acceptable to a chemist specializing in the area. The intention is simply to provide those
practicing engineers who have not previously had reason to consider isomerization with
a basic introduction to the subject.
Isomerization by either Friedel-Crafts or dual-function catalysts is generally thought to
entail intramolecular re-arrangements of carbonium ions as illustrated for pentane:
CH
3

1. CH
3
- CH - CH
2
- CH
2
- CH

3
⇔ CH
3
- C - CH
2
- CH
3

⊕ ⊕
There appear to be two schools of thought regarding the Friedel-Crafts mechanism.
Perhaps each mechanism is operative and the disagreement is merely over their relative
importance under specific circumstances.
Friedel-Crafts isomerization is believed by some to require the presence of traces of
olefins or alkyl halides as carbonic ion initiators, with the reaction thereafter proceeding
through chain propagation. The initiator ion, which needs to be present in small amounts
only, may be formed by the addition of HCl or HAICI
4
to an olefin, which is present in the
paraffin as an impurity or which is formed by cracking of the paraffin:
2. RCH = CH
2
+ HAICI
4
→ RCHCH
3
+ AICI
4
-

⊕

The initiator then forms a carbonic ion from the paraffin to be isomerized:
3. RCHCH
3
+ CH
3
-CH
2
-CH
2
-CH
2
-CH
3
⇔ RCH
2
CH
3
+ CH
3
-CH-CH
2
-CH
2
-CH
3

⊕ ⊕