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Siwes - Industrial work experince technival report
Computer Science (Ahmadu Bello University)
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CHAPTER ONE
1.0
INTRODUCTION
The growing concern among our industrialists that graduates of our
institutions of higher learning, lack adequate practical background studies
preparatory for employment in industries, led to the formation of Students
Industrial Work Experience Scheme (SIWES) by ITF in 1993/1994.
(Information and Guideline for SIWES, 2002).
ITF has one of its key functions; (1) to work as cooperative entity with
industries and commerce where students in institution of higher learning
can undertake mid-career work experience attachment in industries which
are compatible with students area of study (Okorie 2002, in Asikadi
2003).
1.1
DEFINITION OF SIWES: The students industrial work experience
scheme (SIWES) is a skill training programme designed to expose and
prepare Nigeria Students studying occupationally-related courses in
higher institutions the experience that would supplement their
theoretically learning. It seeks to bridge the gap existing between theory
and practice of Engineering, Agriculture, Technology, Environmental
Science, Medical Sciences, Pure and Applied Science Programme in the
Nigeria tertiary institution.
1.2.0 PURPOSES OF SIWES
It is aimed at exposing students to machines and equipment professional
work methods and ways of say guiding the work areas and workers in the
industries and other organization.
The scheme is a tripartite programme involving the tertiary institution and
industry (the employers of labour) and the industrial training fund.
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1.2.1 OBJECTIVES OF SIWES
The objectives of SIWES among others include;
 Prepare students for the industrial work situation which they are likely to
meet after graduation.
 Provide an avenue for students in institutions of higher learning to
acquire industrial skills and experience in their approved course of study.
 Expose students to work methods and techniques in handling equipment
and machinery not available in their institutions.
 Provide students with an opportunity to apply their knowledge in real
work situation there by bridging the gap between theory and practices.
 Enlist and strengthen employer’s involvement in the entire educational
process and prepare students for employment in the industry and
commerce (information and guideline for SIWES 2002).
1.3
BRIEF HISTORY OF PLACE OF ATTACHMENT (KRPC)
Kaduna Refining and Petrochemical Company Limited (KRPC) is a
subsidiary of Nigerian National Petroleum Co-operation (NNPC). KRPC
was commissioned by Alh. Shehu Shagari, President Commander-inChief of the Armed Forces Federal Republic of Nigeria on Saturday 25 th
October, 1980. Its initial capacity was 100,000 Barrels per Stream Day
(BPSD). As the third Refinery in the country, it was established to cope
with the growing demand for petroleum products, especially in the
Northern part of the Country.
The refinery was designed to process both Nigerian and imported crude
oils to fuels and lubes products. In December 1985, the fuels sections of
the refinery was successfully debottle necked from 50,000BPSD to
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60,000BPSD,
bringing
the
total
refinery
installed
capacity
to
110,000BPSD.
In March 1988, the 30,000MT per annum, Linear Alkyl Benzene (LAB)
Petrochemical plant was commissioned. The petrochemical plant, being a
downstream of plant of the refinery, derives its entire raw materials
including utility supplies from the refinery.
KRPC was established to efficiently and profitably process crude oil into
refined petroleum products and manufacture (LAB), Tins and Drums for
domestic consumption and export.
PERSPECTIVE
NNPC embarked on commercialization exercise the same year 1988 and
it became necessary to merge the two plants (refinery and petrochemical
plants) to form a single subsidiary company of NNPC known as Kaduna
Refining and Petrochemical Company Limited (KRPC).
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1.3.1
BROAD ORGANOGRAM FOR KRPC
MANAGING DIRECTOR KRPC
MANAGER SUPPORT STAFF
MANAGER MAT. MANAGEMENT
DEPUTY MANAGER, TOTAL QUALITY MANAGEMENT
MANAGER PLANNING, BUDGET & MONITORIND DEPT.
COMPANY SEC./LEGAL ADVISOR
MANAGER AUDIT
DEPUTY MANAGER COMMERCIAL
EXECUTIVE DIRECTOR OPERATIONS
EXECUTIVE DIRECTOR SERVICES
MANAGER PRODUCTION
MANAGER HUMAN RESOURCES
MANAGER POWER PLANT & UTILITIES MANAGER FINANCE & ACCOUNT DEPARTMENT
MANAGER PROD. PLANNING & QUALITY CONTROL
MANAGER PUBLIC AFFAIR
MANAGER FIRE, SAFETY & ENVI. POLLUTION
MANAGER ADMIN SERVICES
MANAGER MAINTENANCE
DEPUTY MANAGER SECURITY
MANAGER ENGR. & TECHNICAL SERVICES DEPT.
MANAGER MANUFACTURING
1.4
INTRODUCTION TO SECTION OF INDUSTRIAL TRAINING
Fig. 1.0: ORGANOGRAM OF KRPC
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Production department is the core of KRPC for it is where the refining of
crude oil and the production of the petrochemical products are being
carried out. Production department is headed by a Manager and has four
sections each headed by Deputy Manager. Below are the sections;
 Fuels Section
 Lubes Section
 Linear Alkyl Benzene (LAB)
 Oil Movement.
The fuels section is made up of area 1, area 2 and area 3, while the lubes
section is made up of area 4, area 5 and area 6. Linear Alkyl Benzene is
made of Area 1 and Area 2, same with the Oil movement.
But the main focused is on linear Alkyl benzene section particularly Area 1and
Area 2 , where I undertook my industrial training for a period of six (6) months.
The linear alkyl benzene section also called the petrochemical department is
charged with the sole aim of producing linear alkyl benzene as it final product
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1.4.1: BROAD ORGANOGRAM OF UNITS IN PETROCHEMICAL
(LAB) SECTION
LA
AR
BE
A
9
11
M
T
:
//
D
A
Y
Fig1.1: LAB organogram.
The area1 section of petrochemicals is made of three units namely;
1. Hydrogen desulphurisation unit (HDS)
2. Molecular extraction unit (MOLEX)
3. Hot oil system
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The area2 section is also made of three units namely:
1. Paraffin conversion to olefin unit (PACOL)
2. Thermal hydro-de alkylation unit (THDA)
3. Hf alkylation unit.
1.4.2 Hydrogen desulphurization unit (HDS): this unit is also called
unit 35 in KRPC, it is charged with the sole aim of producing treated
kerosene from normal kerosene. This done by reacting purified and
compressed hydrogen from compressor with normal kerosene at an
elevated temperature of 280egree to remove elements like (sulphur,
chlorine, oxygen nitrogen etc.) and hence producing treated kerosene,
sour water and naphtha with much less or no sulphur content and with
low specific gravity. The main product is treated kerosene while the by
product is sour water (H2S, HCl, H20 NH3……). The essence this unit is
to reduce/remove the sulphur content in the kerosene to make it easy for
the MOLEX unit to break the molecules.
C12H25SNOCL+3H2= C12H26 + (HS + HN3 + H2O + HCL)
Kerosene
hydrogen
treated kerosene Sour water
1.4.3 Molecular extraction unit (MOLEX): this unit is called unit30. It
uses treated kerosene from the HDS unit as it raw material. Here the
kerosene molecules are broken by heating it up to a temperature of
285degree to produce paraffin, kerosene solvent and naphtha.
(C12H26)n + heat = (C5H12)n + (C3H8)n + ((C2H5)n + (CH)n)n
Treated kerosene
paraffin kerosene solvent
Naphtha
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1.4.4 Hot oil system (HOS): the hot oil system is the main heating
system in the petrochemical department. The system operates by heating
up oil in the heater and pumping the heated oil through pipes to where
heating services are required in the plant. The hot oil is mainly used to
increase the temperature of fluids passing through pipes.
1.4.5 Paraffin conversion to olefin unit (PACOL): also called unit31
with the addition of heat, hydrogen and a catalyst (platinum) converts
paraffin (saturated hydrocarbon) to olefin (unsaturated hydrocarbon). It is
a chemical reaction called dehydrogenation reaction occurring at a
temperature between 1700c-1800c
(C5H12) n
Paraffin
+ H
=
hydrogen
(C5H11) n
olefin
+
H2 +
CH4
hydrogen gas naphtha
The hydrogen gas obtained is purified, dried and recycled back into the
compressor for further uses. The olefin obtained is one of the raw
materials for production of linear alkyl benzene.
1.4.6 Thermal hydro-DE alkylation unit (THDA): The unit is also
called unit35. It raw material is reformates from the refinery.
Reformate is a compound containing light and heavy aromatics (benzene
products) like xylene, toluene phenol, isoprene etc. with the aid of heat
and purified hydrogen, the reformate is converted to benzene and other
bye products some of which can be recycled in this unit. Several chemical
reactions that are occurring in this unit are:
 hydro alkylation
it is the principal reaction occurring in the THDA process unit, it is the
hydro-alkylation of toluene to yield benzene and methane as naphtha
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at a temperature of 7270c and the degree of conversion is governed by
the reactor temperature, hydrogen partial pressure and resident time.
Other substituted aromatics like xylene and propylbenzene can also be
dealkylated.
C7H8
+
H2
=
C6H6
Reformate hydrogen
+
CH4
benzene
methane
 hydro cracking
Compounds like paraffin and naphthalene are unstable at THDA
process condition and can be hydro cracked to benzene and methane
since they cannot be removed from benzene by fractionation.
C7H16
+
H2
=
Reformate hydrogen
C6H6
+
benzene
C7H16 +
2H2 =
C3H8 +
Heptanes
hydrogen propane
CH4
+
4H2
naphtha
hydrogen
2C2H6
ethane
 hydrogenation
it is a side reaction with advantages and disadvantages like the hydro
cracking reaction, the function is to remove the sulphur in thiophene
to form benzene and hydrogen sulphide.
C7H4S
+ 4H20
Thiopene
=
hydrogen
C6H6
+ CH4
benzene
+
methane
H2S
hydrosulphide
 Aromatic ring condensation
A major side reaction in the THDA unit is the condensation of benzene
to produce biphenyl. This reaction is favoured by high temperature
and low hydrogen-to-hydrocarbon ratio, the production of biphenyl is
reduced by limiting the operation temperature and at high hydrogento-hydrocarbon ratio.
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2C6H6
=
C12H10
Benzene
+
3H2
biphenyl
hydrogen
 Coke formation
Aromatic ring condensation as described above can contribute to the
formation of polynuclear aromatics such as anthracites and fluorine.
These compounds do not tend to reach equilibrium and have high
tendency to form coke instead.
CH4
=
Methane
C
+
carbon
2H2
hydrogen
In this unit intermediate products like toluene, phenyl, xylene, ethyl benzene
etc. are formed during the processes before the final product which is benzene is
formed. The benzene formed is another raw material for the production of linear
alkyl benzene.
1.4.7 HF-ALKYLATION UNIT: this is the most important and complicated
unit in the petrochemical department where the linear alkyl benzene (LAB) is
produce. The raw materials for this section are benzene from THDA unit, olefin
from PACOL unit and hydrofluoric acid (HF) which serves as a catalyst for the
process and it is recovered at the end of the process. A lot of intermediate
products like paraffin, naphtha, light and heavy aromatics and light and heavy
alkylate and obtained during this process with the final product being linear
alkyl benzene.
C6H6
+
C5H11
Benzene Olefin
+
HF
=
C6H5-C5H11
+
H2+
HF
hydrofluoric linear alkyl benzene hydrofluoric acid
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1.5: FLARE:
The flare is a long pipe through which unwanted, unreactive and incondensable
gases are burnt away to the atmosphere.
All unwanted flue gases, polymers and water pass through a common heater
both from the refinery and petrochemical sections to a storage tank called
90D05 which help to remove liquid entrainment (polymer and water) from the
flue gases before sending it to the flare for burning
The air fin cooler around 90D05 helps to cool the flue gas to about 50 0C before
it enters into the drum, it is designed such that 1kg/cm2 (98.07N/m2).
A flare can be started using the following procedures
 Air and flue gas are mixed in the ratio of 2:3, with a plug that sparks up
the fire.
 The fire started is called the pilot fire, and it is always and constantly on
even the flue gases are not send to the flare.
 Flue gases come in contact with the pilot fire at the tip of plant to start
the fire.
 If the liquid level in 90D05 is above 80%, flow regulatory control valve
triggers the transmitter which send signal to the pumps to pick
automatically to send the liquid to oil movement to ovoid over flow
around the tank
 Although the gases are harmful to the environment, there is a lot of
treatment down before the flue gases are sent through the header to
tank 90D05 to the flare.
 90D05 is called the knockout drum because it is use to knockout the
liquid from the flue gases
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f
Fig1.2 the flare and knockout drum (90D05)
CHAPTER TWO
2.0
SAFETY INDUCTION COURSE
It is the culture of KRPC that every IT Students, SIWES, NYSC and
New staffs taken most attend two days fire and safety induction course
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Before starting any work at the company.
2.1.0 SAFETY: May be defined as accident prevention or freedom from risk,
harm and damage.
2.1.1 FUNDAMENTAL SAFETY PRINCIPLE
There are three fundamental safety principle, these are;
i.
Accident are caused
ii.
Steps must be taken to control accident
iii.
Without correction, the same type of accident will occur.
2.2
HAZARD
Hazard is a disaster which can occur in a place of work. It is also the
potential to cause harm.
2.3
i.
TYPE OF HAZARD
Chemical Hazard: This is the type of hazard which involves chemical
substances which can be inhale or expose to human in a work place
especially chemical laboratory.
ii.
Mechanical Hazard: This is another type of hazard that occurs by the use
of machineries i.e. unguarded machinery and moving machinery part.
iii.
Electrical Hazard: This can easily occur when there is any exposure of
electrical conductor which can lead to electrical shock.
iv.
2.4
Other types of hazard include Biological hazard and Ergonomic hazard.
HARMFUL SUBSTANCES
These are substance that causes harm to the human body or the
environment. Some of the harmful substances are:
i.
HF-Hydrofluoric acid
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ii.
H2SO4- Tetraoxosulphate (vi) acid
iii.
TEL-Tetra Ethyl lead
iv.
CO-Carbonmo oxide
v.
NH3-Ammonia
vi.
H2S-Hydrogen Sulphide
vii.
RAS-Radioactive Source.
viii.
Benzene
2.5
HOW HARMFUL SUBSTANCES ENTER THE HUMAN BODY
 Inhalation-via nose
 Absorption-via skin
 Injection-via direct contact
 Ingestion-via mouth
2.6
PREVENTIVE MEASURES OF HARMFUL SUBSTANCES
 Eliminating the hazard
 Educate the workers
 Monitor the workers
 Guard the hazard
 Protect the workers
 Enforcement of safety rules and regulation
 Pay off the worker.
2.7
FIRE
Fire is defined as rapid chemical combination of three components i.e.
fuel, oxygen and heat.
2.7.1 CLASSES OF FIRE
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I.
Class A Fire: Fire resulting from burning materials e.g. wood, paper,
textile plastic etc. it can be extinguished by cooling.
II.
Class B Fire: Fire from liquid hydrocarbon e.g. petrol, diesel, kerosene
and cooking oil. It can be easily extinguished by smothering.
III.
Class C Fire: Fire from gaseous hydrocarbon e.g. cooking gas (LPG). It
can be extinguished by starvation i.e. by preventing the source of the fuel.
IV.
Class D Fire: Fire resulting from metal and metallic compounds very
reactive metals like Na, K, Ca, and compound like Tin-ethyl aluminium
(TEA) when exposes to air, H2O Spontaneous explosion.
V.
Class E Fire: Electrical fire classified by American as class E. These fire
from electrical appliance e.g. heater, meter etc it can easily be
extinguished by disconnection.
2.8
PRINCIPLES OF ACCIDENT PREVENTION
2.8.1 DEFINITION OF ACCIDENT
Accident is an unplanned event in a series of events that may lead to
Injury of person, damage to property or both or all of the above.
2.8.2 TYPE OF ACCIDENTS
There are three type of accidents
(a)
Injury accident
(b) Property damage accident
(c) Near miss event
2.8.3 CAUSES OF ACCIDENT
The two main causes of accident are:
1. Unsafe acts
2. Unsafe condition
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Other causes are:
Lack of knowledge , Careless attitude, Working without authority, Lack
of ability, Poor/Defective working tools and/or equipment, Taking short
cuts etc.
2.8.4 THE REASONS FOR ACCIDENT PREVENTION
There are three (3) major reasons for preventing accidents to personnel.
a.
Moral
b.
Economic
c.
Legal
2.8.5 ACCIDENT PREVENTIVE
The various methods employed for accident prevention are:• Posters – planned campaigns
• Personal reminders of working practices /hazards
• Safety sticker display of known hazards
• Workers briefing on hazards, either general or specific (Tools box Safety
Talk)
• Miscellaneous literature to provide information
• Shop floor publication/company newspapers
• Technical advice reference and data books
2.9
WORK PERMIT:
Permit work can be defined as a tools or
procedure for proper control in hazardous conditions.
2.10
TYPES OF WORK PERMIT
i.
Cold work permit
ii.
Hot work permit
iii.
Vessel/entry permit
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iv.
Excavation clearance certificate
v.
Electrical Isolation permit
vi.
Acid area work permit
2.11 P.P.E (PERSONAL PROTECTIVE EQUIPMENT)
 Head ---------------------------------- helmet
 Body ---------------------------------- Overall
 Eye ------------------------------------ Google
 Ear ------------------------------------ Ear muff
 Hand ---------------------------------- Hand glove
 Face ----------------------------------- Face shield
 Nose ---------------------------------- Musk
 Acid ----------------------------------- Acid Suits.
Fig. 2.0: Safety Wears.
CHAPTER THREE
3.0 DISTILLATION
Distillation is a method of separating mixtures based on differences in
their volatilities in a boiling liquid mixture. Distillation is a unit
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operation, or a physical separation process. Commercially, distillation has
a number of applications. It is used to separate hydrocarbons into more
fractions for specific uses such as transport, power generation, heating
and domestic uses.
Distillation takes advantage of one of the physical characteristics of each
hydrocarbon i.e. its boiling point. The basic mechanics consist therefore
heating the crude (without changing the structure of any component) and
then fractionating it into groups.
The characteristics of these groups are linked to the market needs for
directly commercial products, and to the specifications of the process
plants for the products destined to undergo a subsequent treatment.
The percentage of the products, meeting the specifications, depends
solely on the type of crude processed and the industrial plant most
commonly used for distillation is the topping unit.
A typical fractionating Scheme can be divided as follows:
 Feed
 Preheating
 Preflash
 Heater
 Column for the stripping of side product
 Fractionating overhead system with its sub-units
3.1
FEED
The feed is made up of kerosene, sometimes of particular products
coming from previous treatments. To overcome pressure drops in the
most equipment, the feed is introduced into the unit with high pressure
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pumps (about 70kg/cm2). The pumps, because of a problem of the
dimension of lines, are almost always installed in the tank zone.
Furthermore, there are always standby pumps for the feed and booster
pumps to ensure the continuity of the feed, and for emergencies they are
protected by an automatic blocking system. The flow rate is measured in
the unit area, on the cold product, up-stream of the water and soda
injection. Also the flow rate is measured on the delivery of the feed
pump.
3.1.1 TOPPING FEED DIFFERENT LAY-OUTS
REFINARY
PLANTS AREA
TOPPING UNIT
Battery Limit
Kerosene
Tank
Fig 3.0: topping feed
3.2
PREHEATING OF THE FEED
Preheating is carried out by heat exchangers, recovering heat from the
products to storage and from the various refluxes. Floating heat
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exchangers are usually used to preheat the feed to certain temperature,
conserve energy, heat recovery and heat maximization.
Fig. 3.1: typical heat exchanger arrangement in LAB section
3.3
PREFLASHING
The pre-flash column is usually introduced to separate the gases and sour
water from the kerosene in order to avoid pressure built up in the heater
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or fractionating Column. The gases that are separated may be treated for
flaring or re-injected for further kerosene production or distributed to
companies in need of them.
This is illustrated in figure 3.2
PURPOSE OF PRE-FLASHING
To top hydrocarbon to avoid overpressure in the main fractionating
column
Pre-flash Column
Furnace
Main Column
Light naphtha
Heavy naphtha
Linear alkyl benzene
Light alkylate
Heavy alkylate
Residue
Hydrocarbon
Fig3.2: pre-flashing of feed
3.4
HEATER
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The heater or furnace is the last piece of equipment that supply the heat to
the hydrocarbon before it enters the main fractionating column, it is a
piece of equipment designed to generate heat. The temperature at which
the crude kerosene enters into the heater is usually about 220 0C. The
heater supplies the heat required to the crude oil in order to reach the
process temperature i.e. 3100C to 3500C by burning refinery fuel gas
and/or fuel oil. In KRPC heater heat is generated by using the basic
principles of combustion which is produce with burners that combine fuel
and air and the mixture is burnt at the burner tip, in some cases the system
is provided with pre heaters for the air and two fans i.e. force draft fan
and induced draft fan. The force draft fan is for the air to be pre-heated,
while the induced draft fan is to suck the flue gas to send to the stack after
the heat exchanger. The heater can be considered as divided into two
section such as radiation and convection section. The radiation section is
directly included in the combustion and is therefore subjected to
considerably high temperature while the convection section is instead
with the combustion products.
KRPC heaters are provided with soot blowers to remove soot from tubes.
Heat supplies by the heater are supply to the hydrocarbon by means of
coils which are arranged in parallel, for the rational exploitation. The first
spirals are place in the convection and the other in the radiation section;
the coil to superheat the steam needed for the stripping is also installed in
the convection section. Furthermore, on the combustion chamber there
are a number of holes through which a number of burners are fitted to
produce combustion to generate heat. Devices such as temperature and
pressure indicators, flow rate controller, oxygen analyser are installed to
control the rate at which heat is transferred and to monitor the working
condition of the piece of equipment.
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Fig. 3.3
10 H01 HEATER
3.5
MAIN FRACTIONATING COLUMN
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Fractionating column is a column where the actual process of separating
fraction by ‘fractional distillation’ of treated kerosene takes place. The main
column can be considered and divided into three parts such as;
1. Flash section/zone at the feed inlet
2. Stripping section for the residue
3. Fractionating and extraction section for all the other products.
The stripping section contains some trays (usually 6) and the fractionation
section instead has about 50 trays.
The pre- flashed kerosene heated up to the designed temperature about
(310-3500C) by the heater is fed to the flash zone in the main
fractionation where the vaporised kerosene is flashed and separated into
vapour and liquid, the heater discharge temperature must be sufficiently
high to cause vaporization of all the products withdrawn above the flash
zone plus the run back rate taking account of the effect of the bottom
stripping team injection.
Superheated steam is introduced between the bottom liquid level and the
first tray, the steam by lowering the partial pressure (temperature and
pressure being equal), allows further vaporization and therefore a more
selective fractionation.
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Fig. 3.4: Main Fractionation Column & Stripper
3.5.1 STRIPPING COLUMN-SIDE PRODUCT
Stripping column is a column installed close to the main fractionators to
strip the distillate or side products drawn off from the fractionators. Each
side product drawn off from the main column has its own stripping
column. Stripping system is employed in HF-Alkylation unit.
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In the case of HF-Alkylation unit the fractionating column has side
stripper i.e.
 Hydrofluoric acid stripper
 Polymer (continuous boiling mixture ) stripper
 Alkylates stripper
 Linear alkyl benzene stripper
Normally the strippers have some trays in particular cases; they have five
in the LAB section. The inlet for the product coming from the main
column is in the upper part and superheated stem is introduced between
the bottom liquid level and the first tray. As in the main column the stem
by modifying the equilibrium allows subsequent vaporization of the very
light part of which is left in the extracted product (the flash point). The
vaporized parts ant the steam return to the main column in the section
higher than the one they came from.
3.5.2 FRACTIONATION OVERHEAD SYSTEM
The vaporised fraction in the fractionating column which are not drawn
off from the column passed to the top of the column and leave since the
product leaving the top of the column are in vapour state, it is therefore
necessary to return the condensable one to the liquid state and cool the
incondensable ones. In unit 32, the vapours to be condensed go through
the first exchanger of the unit, a group of air coolers and a water cooler in
that order. However, condensed or uncondensed the reach the overhead
accumulator, in which the separation of hydrocarbon/water and liquid
phase/gas take places.
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3.6
PRODUCTS
The products obtained from linear alkyl benzene section after the Heating
fractionation, distillation and condensation of kerosene and reformate are
as follows:
i.
Whole Naphtha
ii.
Treated kerosene
iii.
Kerosene solvent and paraffin
iv.
olefin
v.
toluene and benzene
vi.
linear alkyl benzene
3.6.1: WHOLE NAPHTHA
Whole naphtha from petrochemical department is defined as an overhead
product which is composed of gas, light naphtha and heavy naphtha
fractions. This product is sent directly to the naphtha hydro treating unit
in the refinery without intermediate tank storage, because of high vapour
pressure. ASTM endpoint of whole naphtha shall not exceed 1700C, since
binaphthenic compounds contained in the heavier fraction of Nigerian
crude oil will behave as a catalyst poison for the catalytic reforming unit
(CRU).
3.6.2: Treated kerosene: this product is obtained from the hydrogen
desulphurization unit. Treated kerosene is kerosene with little or no amount of
sulphur presents it, it also has other elements like: nitrogen oxygen chlorine
removed from it. Treated kerosene can be used for cooking as insecticide raw
material and for making spirits and mainly as raw material in the MOLEX unit
to produce kerosene solvent and paraffin.
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3.6.3: Kerosene solvent: it is a by-products obtained in the MOLEX unit during
the molecular extraction of treated kerosene. Kerosene solvent is very important
in the petrochemical industries because it is pure and lighter than kerosene and
as such can be used as raw material for several petrochemical products like:
insecticides, spirits G.B etc.
3.6.4: Paraffin: paraffin is a saturated hydrocarbon (alkanes) obtained after
heating kerosene and breaking it long molecular chain in the MOLEX unit. The
paraffin produced can be used in making candle wax, producing insecticides
and as raw materials in the PACOL unit to produce olefin.
3.6.5: Olefin: olefin is one of the major raw materials for the production of
linear alkyl benzene. It is produced by dehydrogenating paraffin, making
unsaturated and more reactive. The olefin is used directly with benzene to
produce linear alkyl benzene.
3.6.6: Benzene: benzene is a product obtained after a long and complicated
process in the thermal hydro-DE alkylation unit of the petrochemical section of
KRPC. The raw materials are reformates from the refinery which is processed
using heat and hydrogen to remove the alkyl group and other compound
attached to the benzene ring called reformate. The benzene obtained can be sold
and also use as raw material for production of linear alkyl benzene.
3.6.7: Linear alkyl benzene: this is the final and most important product in the
LAB section of KRPC. In fact the section linear alkyl benzene is named after
the final product its produces. A truck of linear alkyl benzene is worth 9million
naira. The product is mainly of detergent quality and is used to produce all kinds
of detergents. It raw materials are benzene, olefin, hydrofluoric acid and heat.
3.6.8: By-products: these are intermediate products obtained in almost all the
units in the LAB sections in KRPC. These intermediate products are recycled,
sold or discarded, they are: light and heavy naphtha (all units), sour water (HDS
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unit), and kerosene solvent (MOLEX unit), toluene and xylene (THDA unit),
continuous boiling mixtures, polymer and light and heavy alkylates in hfalkylation unit
3.7. Raw materials
The major raw materials in LAB sections are:
3.7.1 Kerosene: the kerosene is sent to LAB section from the refinery
section of KRPC. The kerosene usually sent is of the form C15 (heavy
kerosene) or C9 (light kerosene) but the common one is C12. It also contains
other elements like sulphur, nitrogen, chlorine, oxygen and some radicals.
The kerosene enters LAB through the HDS unit i.e. tank (tk96).
3.7.2: Reformates: Reformate is a compound containing light and heavy
aromatics (benzene products) like xylene, toluene phenol, isoprene etc. it is
also sent from the refinery in form of heavy and light aromatic compounds
which is reduced to simpler forms become entering the THDA unit of LAB.
3.7.3: Hydrogen: the hydrogen is sent from the refinery to both the HDS
and THDA units in LAB. Where they are dried and purified by the
compressors before sending it into the systems, its major functions react with
the other compounds attached to the kerosene and reformate to produce their
pure forms.
CHAPTER FOUR
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4.0
PROCESS DESCRIPTION OF HYRODEN DESULPURIZATION
UNIT
 In the hydrogen desulphurization unit (HDS), kerosene undergoes
several stages of processing before reaching it final stage where the
final product is obtained. The main aim of this unit is remove sulphur
and other contaminants from the kerosene since the MOLEX unit
does not tolerate sulphur above 5ppm.
 Kerosene between C3 and C25 from refinery contains contaminants
like sulphur, nitrogen, chlorine, oxygen and some free radicals which
are not easily removed. HDS unit uses hydrogen and molybdenum
alumina as a catalyst to remove the contaminants forming a product
called sour water (H2S, HCL, NH3, H2O etc.)
 Kerosene from tank (90tk30) enters into the storage drum (35D01)
and pumped by pumps (35P02A and 35P02B) at 70kg/cm 2 through
the pipes to heat exchangers (35E01A and 35E01B) where it is
preheated to temperature of about 1100c by hot product passing
counter-currently and hot oil.
 Compressor (35K01A and 35K01B) compresses purified hydrogen
from the refinery from 20kg/cm2 to 56kg/cm2 and pumped by pumps
(35P01A and 35P01B) through pipes to meet with the kerosene
before entering the heater (35H01) which heat the feed to a
temperature of about 2700c-2800c.
 From the heater the feed enters into a continuous stir tank reactors
(35R01A and 35R01B) connection in series to provide enough
resident time and ensure maximum conversion, the reaction is
exothermic, the product leaves the reactors at a temperature between
2800c-3150c and passes through heat exchanger (35E01A and
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35E01B) again counter-currently to preheat the feed so as the
enhance heat recovery and heat maximization.
 The product is then passed through air fin cooler (35A01), a
condenser to cool the product before entering a high pressure
separator drum (35D03) where sour water is removed through the
boot, excess hydrogen comes out at the top to the compressor called
recycled hydrogen, kerosene comes out from the bottom to a low
pressure separator drum (35D05) where hydrogen sulphide (H2S) is
knocked off and sent to the flare for combustion.
 Product from bottom of 35D05 passes through heat exchanger
(35E03) where is heated up and enters into the stripper column
(35C01) where it is heated with hot oil through heat exchanger
(35E05), the top product with naphtha containing small of H 2S is
send to the refinery for PMS production and some of the naphtha is
recycled, the bottom product which is treated kerosene containing
none or less than 1ppm of sulphur is pumped by pumps (35P03A and
35P03B) to the MOLEX unit and treated kerosene storage tank.
 Drum (35DA852) is design to teat sour water from drum (35D03), it
has a heater and heat exchanges to do the heating and separates the
sour water into less harmful components.
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Fig4.0: process flow sheet for hydro-desulphurization.
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4.1 PROCESS DESCRIPTION FOR PARAFFIN CONVERSION TO OLEFIN UNIT
 The conversion of paraffin to olefin is a chemical reaction called
dehydrogenation reaction at a temperature between 1700c to 1800c
using a platinum based catalyst (DCH-t).
 Paraffin from MOLEX unit and recycled paraffin from the PACOL unit are
store in a drum (31D01)
 From (31D01) it is pumped by (31P01A&B) through heat exchanger
(31E01A&B) to heat it up to heater (31H01) where paraffin is heated
counter currently at temperature between 6500c to 7000c , purified
hydrogen gas from the compressor mixed with the paraffin before
entering into the heat exchanger (31E01A&B).
 The mixture enters into reactors (31R01A&B) where reaction occurs, the
product moves out of the reactors and through (31E01A&B) to pre-heat
the incoming paraffin and itself being cooled, it then goes through the air
fin cooler (31A01) for further cooling.
 The cooled product enters in the high pressure separator drum (31D03)
where hydrogen gas is separated from the liquid mixture.
 The hot hydrogen gas containing water and particles is taken by pump
(31P02) to (31D04) a drum having a boot which separates the particles
allowing only the pure dry hydrogen gas to leave through the top and
recycled back into the compressor, if the hydrogen is in excess, it is sent
to the hot oil heater or flare for combustion.
 The liquid part containing paraffin, olefin and naphtha leaves (31D04)
and pass through (31EO2) to be heated up to a fractionating column
(31C01).
 The column is heated from the bottom with hot oil and medium pressure
steam, the top product being naphtha is pumped by (31P03) to the
refinery.
 The stripper containing paraffin and olefin is sent by pumps (31P04) to
the HF-Alkylation unit where olefin serves as raw material for the
production of linear alkyl benzene, and the paraffin recycled back to the
PACOL unit.
 Only 10-20% of paraffin is converted to olefin in the PACOL unit.
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Fig4.1: process flow diagram for paraffin conversion to olefin.
4.2
PROCESS DESCRIPTION FOR THERMAL HYDRO-DEALKYLATION UNIT.
 The reformate coming from the refinery catalytic reformer is stored in
the reformate tank (90tk30) and it is sent to the thermal hydrodealkylation unit by the reformate pump (90P11A&B).
 Reformate with aromatic within C8-C10 is passed through heat
exchanger (33E01A&B) to heat it up from 600c t0 800c which then enters
the prefractionator (33C01) heated up by hot oil to about 1200c.
 The light product collected as top product and sent to a
condenser(33A01) called air fin cooler and then taken to drum(33D01)
where pumps(33P03A&B) are used to recycle some of the light end back
into the column(33C01) to maintain temperature, pressure and increase
the purity of the product.
 The other light end is further cooled in a condenser (33E05) called trim
cooler and then send to the refinery as naphtha, some of the naphtha is
recycled back into the prefractionator.
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 The bottom product which is heavy aromatic is pumped by pumps
(33P01A&B) through another header to the refinery.
 The main product which is toluene is distilled at the middle of the
column at a temperature of 1110c and is passed through heat
exchanger(33E03) to be cooled and subsequently heat the incoming
reformate.
 The toluene is pumped by pumps (33P02A&B) to drum (33D03) where a
slit ring system is used to move fuel gas in and out of the drum to
maintain a pressure of 1.5kg/cm2
 Some of the toluene is pumped to tank (90tk35) for distribution.
 The other reformate is pumped by pumps(33P04A&B) through heat
exchangers (33E06A,B&C) and (33E07A,B&C) to raise the temperature
which then enters the heater(33H01) to heat toluene to about 650 0c7000c at a pressure between 28-32kg/cm2
 Sulphur is injected into the toluene before entering the heater to protect
the wall of the pipe and prevent toluene from sticking to it.
 Toluene from the heater enters into reactors (33R01A&B) connected in
series to ensure maximum conversion and yield, hydrogen from
compressor (33K01A&B) is added to toluene in the reactor (33R01A).
 The reaction is highly exothermic, so the product is passed through heat
exchanger(33E17) called steam generator where boiler feed water from
drum(33D07) goes into the steam generator to cool the product and
goes out as steam into (33D07) and then to medium pressure steam
generator(M.P steam).
 The product goes out at the top of (33E17) and passed through heat
exchangers(33E06A,B&C) and (33E07A,B&C) to be cooled and
subsequently heat the toluene feed, it is further cooled by air fin
cooler(33A02) and then enters drum(33D03) called high pressure
separator.
 At low temperature and high pressure excess hydrogen goes out from
the top of the drum, part of the hydrogen is send to drum(33D06) from
where it goes to the compressor(33K01A&B) as recycled hydrogen, the
other part of the excess hydrogen is taken to M.P steam.
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 The product is passed through heat exchanger (33E08 and 33E18) for
further cooling which enters drum (33D04) where the product is
separated from the remaining hydrogen.
 The pure hydrogen from(33D04) is passed through (33E08) where some
part goes to the fuel gas and the other part joins the hydrogen from the
refinery and stored in drum(33D05) as the makeup hydrogen for
purification at (33Z01,2 & 3).
 The c1 and c2 from the hydrogen is stored in drum(33D11) and then taken
to the flare, pure hydrogen is taken to the compressor’s make-up side
and is also used to boost the product going to (33D08) and then pumped
by (33P05A&B) to (33D08).
 Some of the product is recycled back into (33D08) and the main part
goes into a clay pot (33C03A&B) to change the colour to gold colour, it
then passes through (33E10) for heating and then to fractionating
column (33C05) where benzene is produced.
 Medium pressure steam and heat exchanger (33E15) heats (33C05),
benzene goes out close to the top at 800c goes through trim cooler
(33E16) and then pumped by (33P07A&B) to benzene storage tank.
 The top product (naphtha, benzene drag and CH4) goes into air fin cooler
(33A03) where it is cooled and then to drum (33D09) for storage.
 Pumps (33P08A&B) pumps the benzene drag where some part is
recycled back into (33C05) and the other part to benzene drag storage
tank.
 The bottom contain heavy aromatic which is heated by (33E15) and M.P
steam and pumped by (33P06A&B) to fractionation column(33C04)
which is further heated by (33E14), where the light aromatic is recycled
back into (33C05) and the heavy aromatic is pumped by (33P09A&B) and
are discharged as fuel to the heater.
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Fig4.2: process description for thermal hydro-dealkylation unit
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4.3 PROCESS DESCRIPTION FOR HF-ALKYLATION UNIT
 The raw materials for this unit are benzene, olefin (alkyl group) and
hydrofluoric acid, recycled hydrogen is preferred because it is sharper
and more reactive.
 Benzene from THDA and recycled benzene and olefin from PACOL unit
from the HF-Alkylation unit pass through heat exchanger (32E01A, B&C)
to be heated, then to a trim cooler (32E02) for cooling.
 Water is pumped by (32P01) from water break tank (FA-70B) to mixed
the fresh and recycled benzene.
 Hydrofluoric acid from drum (32D15) is added to the other raw materials
and pass through trim cooler (32E03) to fractionating column (32C01)
where 90% of the reaction takes place, the product then settles in drum
(32D01).
 Since linear alkyl benzene is lighter it goes out from the top of (32D01),
the HF acid goes out from the bottom based on density and physical
properties.
 The HF acid is pumped by (32P01A,B&C) to column (32C02), some of the
HF pass through a reboiler (32E04) to (32C03) for regeneration, the
others are recycled back to (32C02).
 The stripper (32C03) called the regenerator is where hydrofluoric acid is
regenerated, pure HF goes out from the top and heated by hot oil
(32E06) and taking back into the system, HF from (32C03) enters into
(32D03) a vent drum (receiver & stabilizer) then to (32D04) called the HF
distributor from where the unwanted HF is sent to the flare.
 The linear alkyl benzene goes into (32DO2) for final settling and 10%
reaction, water is introduced to create interface because it has high
affinity for HF which easily dissolves in it.
 The bottom of (32C03) contain polymers, continuous boiling mixtures
(CBM) and HF acid, benzene is sent into the column from the middle to
create a partial pressure so that HF which has lower boiling point (300c)
vaporises with benzene since temperature at the bottom of the column
is 1200c.
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 The polymer and CBM goes into (32D09) and (32D10), the top product of
(32D10) is taken as fuel gas to the heater.
 Bottom of (32D09) contain caustic which is used to bubble polymer into
(32D10), pumps (32P15A&B AND 32D16A&B) is use to pump potassium
hydroxide to (32CO8) and back to (32D10).
 HF and other products goes into (32D11) from the top of (32D09) in form
of gas, (32D11) retain all the unwanted and unprocessed products in the
HF- Alkylation unit, if it is filled up pressure relief valve open to send
some into drum (32D12) and if that is filled up, it is send to (32C8).
 KOH enters (32D09) from the top counter currently to extract the HF
from the mixture, the pure gas is sent to the flare and the liquid part to
the eductor (32J01).
 The product from (32D02) is passed through (32E01A,B&C) to heat the
raw material coming in and create a colour change due to change of
phase in the product and goes into the stripper (32C04) where it is
heated at the bottom by hot oil and a reboiler (32E08).
 The remaining HF acid goes out from the top to the vent drum (32D03)
where it is treaded and sent to the flare.
 The product comes down to (32C05) called the benzene column, where
the unreacted and polymerised benzene is removed from the top,
passed through air fin cooler (32A01) to (32D06) called the off
specification drum, then pumped by (32P06A&B) and heated by (32E10)
to benzene drag tank. Some of the benzene are recycled back to (32C05)
and to the benzene header.
 The bottom of (32C05) is pumped by (32P07A&B) to the paraffin column
where paraffin is removed from the product by heating with hot oil and
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sent to PACOL unit as start up by-pass, paraffin comes out and enters
into (32D17) and some part is used to flush HF acid out of the pipes.
 The paraffin stored in (32D17) is pumped by (32P12A&B) though heat
exchanger (32E13) to filters (32F01A&B) which filters the paraffin before
sending it to flush the pipes through the flush header.
 The remaining paraffin is sent to paraffin recycled tank at PACOL.
 the incondensable gasses goes out from the top of to the ejector which
is used to remove the gases from the vessels to (32D09), nitrogen and
medium pressure steam is use to pressurize the gases and cooled by
(32E17, 18 &19) before sending them to (32D07) as liquid, part of the
gases are sent to heater (34H01) and the liquid from the bottom enters
condensate to chemical sewer where they are neutralized by caustic.
 The product in (32C07) is heated with hot oil from the bottom and
(32E14), the heavy alkylate goes out through the bottom to the heavy
alkylate storage tank.
 The linear alkyl benzene comes out at the middle of the column moved
by pumps (32P10A&B) through trim cooler (32E16) to the linear alkyl
benzene storage tank. The product that those not meet specification is
sent to the off specification tank.
 The light alkylate from the top is sent to light alkylate storage tank and
some recycled.
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Fig4.3 process flow diagram for HF- Alkylation unit
4.4
OTHER PROCESS EQUIPMENT
The main equipment used in LAB other than those that are mentioned and
described before are as follows;
 Reactor
 Pump
 Valve
 Boiler
 Air Cooler/ condenser
 Trim Cooler
 Drum
 Compressor
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4.4.1 REACTOR : A reactor is a container in which reaction takes place, in
petrochemical section of KRPC, the reactors use are made up of high resistant
materials that can withstand high temperature and resist corrosion, the reactors
are usually connection in series to ensure maximum conversion and optimum
yield. The reactors in most cases are located after the heaters or heating
equipment.
Fig 4.3: Reactor.
4.4.2 PUMP: A pump is a device which conveys fluid, chiefly liquid from a
lower to a higher region or from a region of lower pressure to a region of higher
pressure, if used to transport gases will cause cavitations. The two popular type
of pumps used in petrochemical section are centrifugal and reciprocating pumps
this is because it gives uniform and particular pumping rate, they are used to
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transport chemicals, products and raw materials of precise amount and quantity,
these pump are driven by either electric motor or steam turbine.
Fig4.4: reciprocating pump.
4.4.3 VALVES: these devices which are used to regulate the flow,
pressure, level and temperature of a fluid. Types of valves used in LAB
are; gate valve, non-return valve, globe valve, control valve, pneumatic
valves, and safety pressure valves and check valves.
i.
Gate valve is commonly used for isolating purposes or bypassing
faulty equipment during operations. They are either fully open or
closed.
Control valves can be manually operated or by electrical means. They are used
to control the operations condition of most equipment during operation
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Fig4.5: servicing valves
4.4.4 BOILER: Boiler is used to heat water (liquid) and required steam or hot
water. Boiler is used in LAB department to heat the stripping steam and
the fluids that will pre wash the equipment in restarting the plant during
shut down.
4.4.5 TRIM COOLER: Trim cooler is a fixed-tube plate exchanger where
water is used as temperature stabiliser medium. Trim coolers are normally
placed downstream air coolers so that the product passed through them
reaches a stable temperature. The reason is that air cooler are affected by
weather conditions changes, while the trim cooler are not.
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4.4.6 AIR FIN COOLER:
The air cooler is an exchanger where forced air
constitutes the cooling medium which passes externally through a bank of
finned tubes in which hot fluid is being cold. Air coolers are widely used
in refinery operations to cool products whose heat content cannot be
economically recovered with heat exchangers, but must be removed for
handling reasons.
Fig4.6: air fin cooler.
4.4.7 CONDENSER:
Condenser like trim cooler is a fixed-tube plate
exchanger. Its main function is to condense condensable vapours by removing
their latent heat. This type of exchanger is mainly used for top columns vapours
which contains light hydrocarbons and in steam turbines for exhaust steam
condensing
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Fig4.7: A condenser
4.4.8 DRUM: A drum is equipment used basically in petrochemical section of
KRPC to separate products and store them temporarily. They are high
pressure and low pressure drums. The high pressure drum uses high
pressure to separate fluids and the low pressure drum uses low pressure to
separate. Most of the drums have boot. A boot is capable of separated
unwanted particles from the fluid and making more pure and less
contaminated, it is usually situated at the bottom of the drum so the
particles can easily be drained.
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Fig4.8: high pressure separator drum.
4.4.9 Compressor: a compressor is a device use to transport gases only; it
compresses gases by decreasing their volumes and increasing their
pressure, it motor transmit electrical signals to mechanical signals by the
action of the piston in the motor of the compressor.
In KRPC the compressors use are reciprocating compressors which
operates using forward and backward action and has higher compressing
ability, it has parts for compressing both makeup and recycled gases from
a process
It is made up of a suction side where gases enters and a discharge side
where gases leave the compressor, it is designed such that the suction is
larger than the discharge to create a differential pressure across the
compressor, the compressor used has the capacity to compress hydrogen
from 20kg/cm2 to 50kg/cm2
It operates under the following principles:
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 Compressor ratio: ratio of suction to discharge.
 Charles law: pressure increases with increase in temperature as
volume remains constant.
 Boyle’s law: as pressure increases, volume decreases at constant
temperature.
 It follows the general gas law pv/c=constant.
 Compressor displacement.
Compressors normally have four (4) parts:
 Distance peace
 Cylinder
 The crank shaft assembly
 Cross head
Compressors usually have demisters that separate gases from liquids.
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Fig4.9: A typical compressor motor used in KRPC, LAB.
4.5.0 CALCULATIONS AND ANALYSIS OF EXPERIMENTAL AND RECORDED
VALUES.
4.5.1 Calculation of volumes and other parameters of a reactor.
To calculate the volumes of reactors (33R01A&B) and other parameters, having
the following data for treated kerosene.
Molar flow rate of kerosene Fk = 172.3 mol/hr
Pressure at reactor P=70kg/cm2 = 70×98.07=6864.9N/m2
Temperature at reactor T= 3150c = 315+273=588k
Expected conversion in reactor A, Xk=0.9
Expected conversion in reactor B, Xk1=0.1
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Equation of reaction
C12H24S +2H2 = C12H26 + H2S with reaction rate -rk = 1.4C2k
Implies reaction constant K=1.4.
SOLUTION
Fk0, Xk0
Fk0
-rk1, Ck0
XK1
Ck1
From material balance equation
Input= output + disappearance + accumulation…………………………….. (1)
For a continuous stir tank reactor (CSTR), accumulation =
Input = F k 0
Output ¿ F k 0(1−X k )
Disappearance = (−r k )V
So that
F ko=F ko(1− X k )+(−r k )V
………………………… (2)
Rearranging and equating, I have that
X
V
= k
F k 0 −r k
……………………………………………. (3)
Similarly,
X
τ
V
= k=
Ck0 rk F K0
…………………………………… (4)
V c k 0 × Xk Ck 0− Kk
τ= =
=
υ
−r k
−r k
…………………………. (5)
From the equation of reaction,
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dNA
=0
dt
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εk=
2−3
=-0.333
3
Since εk≠0, it is a varying volume case, so that
Ck=
Ck 0 (1−Xk )
(1+ εkXk)
……………………………….. (6)
Since -rk = KC2k
−r k=KC 2 k 0(1−x k ) 2
(1+εkXk )2
……………………………… (7)
From the ideal gas equation PV= n RT
CKO=
Pk 0
6864.9
mol
= 8.314 ×588 =1.4 3
RT
m
Cko=1.4
J
where R=8.314 mol/k
mol
3
m
Substituting equation 7 into equation 3 for -rk
Xk
V
=
F k 0 KC 2 k 0(1− x k ) 2
(1+εkXk )2
(1+ (−0.333 × 0.9 ))
¿
¿2
¿
¿
1.4 × 1.42 (1−0.9)2
¿
V
0.9
= ¿
172.3
V1=281.65 m3
Since the reactors are connected in series, the volume of the second reactor V2
can b calculated as shown below.
Fk0, Xk0
Fk1, XK1
Fk2
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-rk1, Ck0
-rk1
Xk2
Ck1
Ck2
Knowing that
V 2 Xk 1
=
F k 1 rk 1
…………………………………. (8)
So that
Ck 02 (1+ Xk )2
Ck1=
(1+εk × Xk )2
………………………… (9)
Where Xk1=0.1
(1 ± (−0.333 × 0.1 ))
¿
¿
Ck1=
¿
1.4 2( 1−0.1)2
¿
Ck1=1.7
mol
m3
Also
F k1=F k 0 (1−X k 1)
…………………………… (10)
And
-rk1=
KC 2 k 0(1−x k ) 2
(1+ εkXk )2
………………………………... (11)
=172.3(1-0.1)
mol
=155.07 hr
From equation 8, making V2 the subject and substituting
kX k 1
1+ε ¿
¿
V2=
¿2
¿
F k1 X K 1 ¿
¿
……………………. (12)
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(1+ (−0.333 ×0.1 ) )
¿
¿
2
V2=
155.07 ×0.1 ¿
¿
¿
V2=39.8 m3
Calculation of how temperature affects equilibrium conversion in the reactor
and point maximum yield.
Given the reaction between 00c to 3150c
Assuming a homogeneous irreversible reaction
A
J
∆G0=-10280 mol
B
J
∆H 0=-24149 mol
kJ
Heat capacity of thiophene A, =1.01 K
kJ
Heat capacity of kerosene B, =2.01 K
Solution
Given the formula
∆ H r =∆ H r 1 + ∆C p (T 2−T 1)
…………………….. (13)
Where T 1 = 00c= 0 + 298 = 298K
T 2 = 3150c = 315 + 298 = 613K
∆ H r = -24149 + (1.01-2.01)(631-298)
∆ H r = -24438
J
mol
Similarly
∆ G0=−RTIn K 298 …………………. (14)
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∆G
0
K 298 =
е RT
K 298 = е 10280/ 8.314 ×298
K 298 = 63.4
And
1
1
−
T T 298
)………………………………… (15)
InK −∆ H r
¿
=
K 298
R
24439
24439
−¿
8.314 T
8.314 ×298
K= 63.4
¿¿
е¿
¿
K= 63.4 е (¿
2939.5
T
−9.86) ……………………………… (16)
¿
From equilibrium conversion
1−X
¿
Ae
¿¿
¿
¿
K=
………………………….. (17)
A 0¿
C¿
C R C A 0 X Ae
= ¿
CA
It implies that
X Ae =
K
………………………………………………….. (18)
K +1
Table of value for the above formulas as temperature increases
T(0c)
T(K)
K=
2939.5
—
T
X Ae =
9.86
25
298
63.4
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0.9845
K
K +1
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45
65
85
105
125
145
165
185
205
225
245
265
285
305
325
318
338
358
378
398
418
438
458
478
498
518
538
558
578
598
39.7
29.7
17.5
10.9
7.1
4.5
3.3
2.3
1.8
1.4
1.1
0.9
0.7
0.6
0.5
Table4.0 table of equilibrium conversion and rate constant
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0.9754
0.9674
0.9458
0.9158
0.8770
0.8167
0.7609
0.7007
0.6389
0.5776
0.5190
0.4652
0.4142
0.3693
0.3289
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1.2
1
Temperature (K)
0.8
0.6
X
0.4
0.2
0
250
300
350
400
450
500
550
Equilibrium Conversion X
Fig4.10: graph of temperature against conversion.
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600
650
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4.5.2 Designing a mathematical model for the flow description
To design a mathematical model equation for the description of kerosene and
sour water in the reactor, since the reaction is irreversible and the some of the
parameters were experimented and calculated to be as written below
C K 0 =1
mol
m3
C K 1 =1.4
mol
m3
C K 2 =1.7
mol
m3
τ 1 =12min
τ r =3min
equation of reaction
K=1.4
K
k
R
Where K = kerosene and k = rate constant
SOLUTION
Assumptions
 density of the fluid are constant
 the heat capacities of the fluid are constant
V1
F+ F R
V2
FR
F
CK 0
CK1
F
CK2
Taking total material balance for component K.
For reactor one
F+ F R =F+ F R …………………………………… (19)
For reactor two
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CK2
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F+ F R =F+ F R …………………………………… (20)
Component balance for component k, in reactor one
Accumulation = input – output – disappearance……………………. (21)
V1
d CK1
dt
= FC K 0 + (F+ F R ) C K 1 + F R C K 2 - V 1−r k 1 ………………………..
(22)
Since it a first order irreversible reaction, −r k 1 = k 1 C K 1 ………… (23)
Also if
V
F
F
= τ implies V
1
= τ
………………………. (24)
Substituting equations (23) and (24) into equation (22) after dividing through
by V 1 , the equation becomes
d CK 1
dt
1
1
1
1
= τ C K 0 - τ C K 1 - τ C K 1 + τ C K 2 - K 1 C K 1 ……………………
1
1
R1
R1
(25)
Collecting like terms and rearranging the equation and taking initial conditions
1
CK 0
i.e. τ
1
d CK 1
dt
= constant, then
1
1
1
= -( τ + τ
+ K 1 ) + τ C K 2 ………………………………. (26)
1
R1
R1
Component balance for K, in reactor two
V2
d CK2
dt
= ( F+F R ) C K 1 - F R C K 2 - FC K 2 - V 2 K 2 C K 2 ……………. (27)
Applying equation (24), dividing through by V 2 and rearranging the equation
d CK 2
dt
1
1
1
1
= ( τ + τ ) CK1 - ( τ
+ τ ) CK2
2
R2
R2
2
……………………………………… (28)
Therefore equations (26) and (28) are the mathematical description for the
above reaction.
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4.5.3 Calculation of utilities around heat exchangers
To calculate the heating and cooling utilities for the heat exchanger
(33E01A&B) Using problem table method.
Warm feed
3150c
1100c
1500c
Hot product
cold product
600c
Cold feed
Fig4.5.4 heat exchanger (33E01A)
Hot feed
2800c
220 0c
40 0c
Hot oil
cold oil
1100c
Warm feed
Fig4.5.5 heat exchanger (33E01B)
Streams
items
nature
Ts (0C)
Tt (0C)
∆H (KJ)
Cp (KJ/0C)
1
kero/H2S
Hot
315
150
66.3
0.4
2
hot oil
hot
280
40
146
0.6
3
thiophene cold
110
220
63.7
0.6
4
thiophene/H cold
60
220
66.7
1.3
Using problem table method with ∆ T min = 100C
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IF T*hot = T hot -
∆ T min
………………………….. (29)
2
And T*hot = T cold +
∆ T min
…………………………….. (30)
2
The cascade of temperatures will be as shown below
310……………………………………… heat surplus
QH =47kJ
275…………………………-14kJ…………..14
61
225…………………………-50kJ…………..64
111
145…………………………..72kJ…………..-8
41
115……………………………39kJ………..-47
0
65………………………………-10kJ…………-37
10
35…………………………………-18kJ……..-19
28
QC
= 28kJ
Calculating the amount heat in each cascade using the formula below
εCpc
∆ H i=¿
- εCp h ) × ∆T i …………………………… (31)
∆ H 1 = (0 – 0.4) ×35
∆ H 2 = (0 – 1) ×50
= -14kJ
= -50kJ
∆ H 3 = (1.9 – 1) ×80
∆ H4
= (1.9 – 0.6) ×30 = 39kJ
∆ H 5 = (0.4 – 0.6) ×50
∆ H6
= 72kJ
= -10kJ
= (0 – 0.6) ×30 = -18kJ
Pinch temperature of the hot stream = 1200C
Pinch temperature of the cold stream = 1100C
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The heat exchanger networking will be as shown below
11 3150C
1200C
1500C
2 2800C
1200C
400C
2200C
1100C
2200C
1100C
60 0C
Considering the section above the pinch
11 3150C
1200C
2 2800C
1200C
2200C
1100C
2200C
110
Amount of heat in each item is calculated using ∆ H i = Cp × ∆T i
∆ H 1 = 0.4 ×195
= 78kJ
∆ H 2 = 0.6 ×160
= 96kJ
∆ H 3 = 0.6 ×110 = 66kJ
∆ H4
= 1.3 ×110 = 154kJ
Interval temperatures will be
78 = 1.3 (T-110) implies T = 1700C
21 = 0.6 (T-110) implies T = 1450C
Considering the section below the pinch
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1200C
1500C
1200C
400C
1100C
∆ H 1 = 0.4 ×30
= 12kJ
∆ H 2 = 1.0 ×80
= 80kJ
∆ H 3 = 1.3 ×50
= 64kJ
4
Interval temperature will be
52 = 0.6 (T-40) implies T = 1270C
Using the rule CpH ≤Cpc for section above the pinch and CpH ≥Cp c for
section below the pinch, the networking using Grid diagram will b as shown
below.
11 3150C
1200C
2 2800C
1200C
22
QH =47kJ
2200C
75kJ
21kJ
78kJ
1500C
400C
1100C
12kJ
Q C =28kJ
52kJ
So that
The heating utility required = 47kJ
The cooling utility required = 18kJ
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1100C
600C
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4.5.4 Material balance calculation
To take the material balance around the fractionation column (33C01)
Feed is kerosene, K
Top product is naphtha, N
Bottom product is sour water, S
Middle product treated kerosene, P
Overall material balance
K = N + S + P…………………………………….. (32)
Component balances
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Kx = Ny + Sz + Pl………………………….. (33)
4.6: PROBLEMS UNCOUNTED
During my industrial training in KRPC, some problems were encountered
which include:i.
Limited supply of safety wear to the training students such as helmets,
safety boots, overall and hand gloves which are not affordable
ii.
Another problem encountered was the hazardous environment which one
was exposed to, which were dangerous to health
iii.
Most of the sections in LAB department are not working, so practical
knowledge of the sections was limited.
iv.
Transportation is also difficult since the refinery is far from where I stay
and KRPC transportation does not have a particular pickup time.
v.
CAVITATION: This is a process whereby air is present in the impeller
chamber of a pump that is not design to pump air which could result to
overheating and malfunctioning, sometime could lead to the burning of
the electric motor of the pump this is because of low level of fliud in tank
or as a of leakages
4.7
i.
POSSIBLE SOLUTIONS
Adequate safety wear should be made available in order to avoid accident
within the plant.
ii.
Most skill operator are expected to acquire both physical and chemical
knowledge of the entire process, this will create a more secured
environment for both industrial trainees and the operators working within
the plant.
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iii.
Proper housekeeping should be carried out at regular interval to avoid
exposure to harmful substances and provide a work free environment.
iv.
The LAB section should be made working to capacity since it’s a
profitable venture and will solve most of Nigeria’s petrochemical
problems
CHAPTER FIVE
5.0
SUMMARY
In KRPC, production department, the petrochemical (LAB) section is charged
with the sole aim of producing linear alkyl benzene used in making liquid and
powdered detergents of all kind. The basic raw materials are kerosene,
reformate and hydrogen all from the refinery. Several processes are involved in
producing LAB. elements like sulphur, chlorine, nitrogen, oxygen etc. are
removed from the kerosene in the hydro-desulphurization unit(HDS) to produce
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treated
kerosene
through
heating(300-3500c)
in
the
presence
of
a
catalyst(molybdenum alumina), the branched chain attached to the kerosene is
removed in the molecular extraction unit(MOLEX) to produce linear
paraffin(saturated hydrocarbons) and a by-product called kero-solvent through
heating(300-4500c), using dehydrogenation process the linear paraffin is
converted to linear olefin(unsaturated hydrocarbons) at (170-180 0c) in the
presence of platinum based catalyst, in the THDA unit, reformate is converted
to benzene at (80-900c) through heating(650-7000c) with by-products like
toluene, ethyl benzene and medium pressure steam, the olefin and benzene then
combine in the HF-Alkylation unit to yield linear alkyl benzene in the presence
of hydrofluoric acid as catalyst, with by-products like hydrofluoric acid,
polymers, light and heavy alkylates. All the units produce light and heavy
naphtha as by-product too.
5.1 CONCLUSION
During my period of attachment at the petrochemical section of KRPC
production department I was able to understand most of the unit operations and
unit processes in the section, I understood each unit their major importance and
the products each unit produces. The major raw materials, processes involved
and the final products were also understood.
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Furthermore, the operating conditions such as temperature,
pressure, and flow rate for the refining process are also factors
that have a great influence on the products yield and quality.
V.2 RECOMMENDATION
The Kaduna Refining and petrochemical Company is an
integrated refinery for the production of a wider variety of
petroleum products such as lubricating oil, kerosene, petrol,
Automotive Gas Oil (AGO) in the refinery section and linear
alkyl benzene, benzene, kero-solvent, alkylate, polymers,
naphtha ( etc.) in the petrochemical section. In view of the
above, the following recommendations are made.
1. For better productivity, operator of plants should be given
proper orientation on the plant and the job in general
before they commence work.
2. For proper and accurate identification of faults, the
company should make sure they make use of fault
detection equipments.
3. There should be adequate staffing that is, scrutanization
should be made to actually employ those who know the
job and can do it effectively and efficiently.
4. There must be strict adherence to operating conditions for
better yield and high quality products.
5. Regular biennial Turnaround Maintenance (TAM), as is the
industry standard
6. Provision of adequate PPE esp. to SIWES students to
safeguard their health and safety.
REFERENCES
Chiyoda Corporation (1983). Area1 Operational Manual for
hydro-desulphurization.
Chiyoda” 1979 LAB Operational Hand Book, on all units of LAB.
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John J. McKetta Jr (1992). Petroleum Processing Handbook, CRC
Press.
James G. Speight, Baki Ozum (2001). Petrochemical Refining
Processes, CRC Press
Chemical Engineering Coulson Richard Son Volume one 3rd Edition.
J. H Hong (1992) Quality Control and Monitoring Manual.
“KRPC NEWS” Vol.3, No.4 Chiyoda Chemical Engineering Company
Lecture received from my Industrial Supervisor and other operators.
Octave Levenspiel (2006). Chemical Reaction Engineering third edition
Plant Design and Economics for Chemical Engineers. Max. S. Peters Klaus. D.
Timmerhaus. 4th Edition.
Process safety by Stanley M. Englund, M.S, Ch. E, Fellow, American Institute of
Chemical Engineers page 26-59.
Surinder Parkash (2003). Refining Processes Handbook.
WWW. Google.com/ unit Operation for Chemical Engineers accessed 18/09/2011.
WWW. Google.com siwes in Nigeria accessed 20/08/2011.
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