INDUSTRIAL TRAINING REPORT

Indian Oil Corporation Limited, Mathura

(Duration: 15th June 2024 to 15th July 2024)
Submitted in the partial fulfilment
of the requirement for the award
of the degree of
BACHELOR OF THE TECHNOLOGY
IN
Chemical Engineering
Submitted By :
AVESH KUMAR
(Roll No :-2100520510018)

Chemical Engineering Department

Institute of Engineering and Technology, Lucknow

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 (226021)
I am, Avesh Kumar student of INSTITUTE OF ENGINEERING AND
TECHNOLOGY (IET-Lucknow) B.tech (Chemical Engineering) Rollno:-
(2100520510018), have done training in IOCL Mathura refinery from 15/06/2024

to 15/07/2024 under the guidance of Mr. S P Nigam ( DGM, production

department) in following process areas:

1) Overview of refinery
2) Studied FCCU in detail
3) Calculated furnace efficiency

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HOD Signature & Stamp
ACKNOWLEDGEMENT
It has been a great experience for me to complete my training from reputed ‘ Indian Oil
Corporation Limited ‘which has helped me to brush up my practical knowledge regarding
many of our core subjects mass transfer, heat transfer , fluid mechanics and transport
phenomenon .

I would like to thank all our faculty members for clearing up my basics concepts which helped
me throughout my training , as I was a representative of our institute at IOCL, Mathura , I have
tried my level best to put a good conduct . After completion of training I found it immensely
helpful in better visualization of my subjects, not only in supplementing the theoretical
knowledge, but also by gaining highly practical knowledge regarding the actual work carried out
in a Refinery Plant.

I am highly obliged to the learning and Training Department (Mathura Refinery ) For providing
us with this opportunity . My Special Thanks to DGM (PN), Mr S.P Nigam and his entire
team ,whose unwavering support made this training period exceptionally rewarding.

I am also very grateful to my fellow trainees for their teamwork who patiently explained the
working of the plant and provided the needed conceptual understanding for the project. The
series of discussions with them has increased my practical knowledge about the plant and the
industry.

At last , I would like to thank my parents who provided me means for a good stay at Mathura.

I am heartily thankful to each and everyone who has helped me throughout my training .

Thankyou.

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 TABLE OF CONTENTS

S.NO PROCESS UNIT

1) INTRODUCTION (INDIAN OIL REFINERY )

2) MATHURA REFINERY OVERVIEW

3) REFINERY PROCESS

4) PROCESS UNIT DESCRIPTION

4)a FCCU(FLUIDISED CATALYTIC CRACKING UNIT)

5) PROJECT -1
CALCULATION OF FURNACE EFFICIENCY

6) Conclusion and Refrences

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 INTRODUCTION :- (INDIAN OIL REFINERY)
Introduction
Indian Oil Corporation Ltd. is India's one of the prestigious and largest company by sales with a
turnover of Rs.271,074 crore and profit of Rs. 10,221 crore for the year 2009-10, it accounts a
huge toll on india’s economy.
Indian Oil is the highest ranked Indian company in the latest Fortune ‘Global 500’ listings, with a
bench mark of 98th position ( as per report of 2011). Indian Oil's vision is driven by a group of
dynamic leaders who have made it a name Indian Oil Company Limited, a wholly Government
owned company was incorporated on 30 June, 1959 to undertake marketing functions of

)
petroleum products. Later, Indian Oil Corporation Limited (IOC was set up on 1st September,
1964 by joining the Indian Refineries Limited (started in August, 1958) with the Indian Oil

Company Ltd., for better coordination between refineries and marketing. It is also among the
20 largest petroleum companies in the world. The Indian Oil Group of companies owns and
operates 10 of India's 20 refineries with a combined refining capacity of 65.7 million metric
tonnes per annum (MMTPA, .i.e. 1.30 million barrels per day approx.). Indian Oil's cross-country
network of crude oil and product pipelines spans 10,899 km with a capacity of 75.26 MMTPA of

s
crude oil and petroleum products and 10 MMSCMD of gas. This network largstest in the
country and meets the vital energy needs of the consumers in an efficient, economical and

.
environment-friendly manner

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Indian Oil Corporation has four branches:

● Marketing Division with Headquarters at Bombay;

● Refineries and Pipelines Division with Headquarters at New Delhi;
● Assam Oil Division with Headquarters at Digboi ; and ● Research and Development

Centre at Faridabad.

The Assam Oil Division was established on 14th October, 1981 on taking over the refining and
marketing operations of Assam Oil Company Limited.

The Company wholly owns a subsidiary Company like. Indian Oil Blending Limited, which is
engaged in the manufacture of lubricants and greases. The products of the subsidiary Company

are also marketed by the Company. Talking about the product , IndianOil and its subsidiary

(CPCL) account for over 48% petroleum products market share, 34.8% national refining capacity
and 71% downstream sector pipelines capacity in India, the company is flourishing.

SINCE the company is very iconic it has portfolios of many powerful and a much-loved energy
brands like Indane LPG as, SERVO lubricants, XtraPremium petrol, XtraMile diesel, PROPEL,
petrochemicals, etc. It is most trusted brand in figure validating the trust of 56.8 million
households, Indane has earned the coveted status of 'Superbrand' in the year 2009 and now has a
customer base of 61.8 million.

The Corporation also enjoys a 65% share of the bulk consumer, industrial, agricultural and
marine sectors. They aim of maintaining its position as a market leader and providing the best
quality products and services, Indian Oil is currently investing Rs. 47,000 crore in a host of
projects for augmentation of refining and pipelines capacities, expansion of marketing
infrastructure and product quality upgradation and also provides employment tp thousands of
employees.

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Objectives

Their main objectives as approved (June, 1984) by Government are as follows:

● To serve the national interests in the oil and related sectors in accordance and consistent
with Government policies.
● To ensure and maintain continuous and smooth supplies of petroleum products by way
of crude refining, transportation and marketing activities and to provide appropriate
assistance to the consumer to conserve and use petroleum products most efficiently.
● To earn a reasonable rate of return on investment.
● To work towards the achievement of self-sufficiency in the field of oil refining, by

setting up adequate domestic capacity and to build up expertise for pipe laying for

crude/petroleum products.

● To create a strong research and development base in the field of oil

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Products Services I.O.C Refineries:

● Auto LPG refining ● Refining ● Digboi Refinery,

and stimulate the ● Pipelines ● Guwahati Refinery,
development of new ● Marketing
● Barauni Refinery
petroleum products ● Training
● Gujarat Refinery
formulations with a
● Research
view to eliminate their ● Haldia Refinery
imports, if any . & Development
● Mathura Refinery
●

● Aviation ● Panipat Refinery

Turbine ● Bongaigon
Fuel (ATF Refinery
● Bitumen
● High Speed Fuel
● Industrial Fuels
● Liquefied
Petroleum Gas
● Lubricants and
Greases
● Marine Fuels
● MS/Gasoline

Petrochemicals

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 MATHURA REFINERY
The Mathura Refinery, owned by I.O.C.L is situated in Mathura, Uttar Pradesh. It is the sixth
refinery of Indian Oil was commissioned in 1982 with a capacity of 8.0 MMTPA to meet the
demand of petroleum products in north western region of the country, which includes National
Capital Region. Refinery is located along the Delhi-Agra National Highway about 154 KM away
from Delhi. The refinery processes low sulfur crude from Bombay High, imported low sulfur
crude from Nigeria, and high sulfur crude from the Middle East.
The refinery, which cost Rs.253.92 crores to build, was commissioned in January;
1982.Construction began on the refinery in October 1972. The foundation stone was laid by
Indira Gandhi, the former prime minister of India. The FCCU and Sulfur Recovery Units were
commissioned in January, 1983. The refining capacity of this refinery was expanded to 7.5
MMTPA in 1989 by debottlenecking and revamping. The present refining capacity of this
refinery is 8.00 MMTPA.

The major secondary processing units provided were Fluidised Catalytic Cracking Unit (FCCU),

e
Vis -breaker Unit (VBU) and Bitumen Blowing Unit (BBU). Th original technology for these

units was from erstwhile USSR, UOP etc. Soaker drum technology of EIL was implemented in
VBU in the year 1993. For production of unleaded Gasoline, Continuous Catalytic Reforming
Unit (CCRU) was commissioned in 1998 with technology from Axens, France, capacity of

Mathura Refinery was increased to 8.0 MMTPA.

Mathura refinery has produced petrol of grade BS- VI and had patented it which is currently
being used in delhi has a sulphur concentration emission of 10 ppm.

9
Mathura Refinery is having its own captive power plant, which was augmented with the
commissioning of three Gas Turbines (GT) and Heat Recovery Steam Generator (HRSG) in
phases from 1997 to 2005 using Natural Gas (NG) as fuel to taken are of environment.
For upgrading environmental standards, old Sulfur Recovery Units (SRU) was replaced with new
Sulfur Recovery Units with 99.9 % recovery of sulphur. Additional Sulfur Recovery Unit is
under implementation as a hot standby .Refinery has planted 1,67,000 trees in surrounding areas

gio
including refinery & township and 1,15,000 trees in Agra re ar Mathura Refinery had also set
up four nos. of continuous Ambient Air Monitoring Stations far beyond the working area before

commissioning of the Refinery in 1982 .Its ecological Park spreads across 4.45 acres is a thriving
green oasis in the heart of sprawling Refinery.
At Mathura Refinery, technology & ecology go hand in hand with continuous endeavour for

,
Product Quality up-gradation Energy Conservation and Environment Protection. Mathura
Refinery is the first in Asia and third in the world to receive the coveted ISO-14001 certification

.
for Environment Management System in 1996 It is also the first in the World to get OHSMS

certification for Safety Management in 1998.

UNITS IN MATHURA REFINERY

UNIT PRESENT FEED SPECIAL FEATURES

CAPACITY(TMT
PA) ● Fuels refinery & propylene
CDU 8000 Bombay high ● Product pipeline o
imported- high sulfur MJPL:3.7 MMTPA o Mathura
and low sulfur crude tundia:1.2 MMTPA o MBPL:
1MMTPA
FCCU 1350 Vacuum gas oil ex-
● Bit. Drum filling: by Mktg
IMP. LS & OHCU
● LPG bottling: by Mktg.
bottom
● Crude Recipient thru SMPL
OHCU 1200 VGO ex.IMP. HS ● Captive Power Plant
CCRU 466 Naphtha ● Mode of product despatch –
VBU 1000 Vacuum residue(VR) tank truck, tank wagon and

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DHDS 1100 Straight run gas oil, pipeline
total cycle oil
DHDT 1800 Straight run gas oil
and total cycle oil
Biturox 750 Vacuum residue
PENEX(MS Naphtha, FCC
Quality Up 440 Gasoline heart cut
gradation)
PRIME G+ FCC Gasoline splitter
(FCC Gasoline 525 bottom
desulfurisation)

PRODUCTS:
Finished products from this refinery cover both fuel oil products as well as lube oil base stocks.

1. Liquid Petroleum Gas (LPG)

2. Fuel Oil Products:
● Motor Spirit (MS)
● Mineral Turpentine Oil (MTO)
● Superior Kerosene (SK)
● Aviation Turbine Fuel (ATF)
● Russian Turbine Fuel (RTF)
● High Speed Diesel (HSD) ● Furnace Oil (FO)
● Naphtha , Gasoline
Lube Oil Products:
1. Inter Neutral, Heavy Neutral & Bright Neutral HVI

4. Other Products:

● Slack Wax
● Carbon Black Feed Stock
● Bitumen
● Sulfur

REFINERY PROCESS
The refining process depends on the chemical processes of distillation (separating liquids by their
different boiling points) and catalysis (which speeds up reaction rates), and uses the principles of
chemical equilibria. Chemical equilibrium exists when the reactants in a reaction are producing

11
products, but those products are being recombined again into reactants. By altering the reaction
conditions the amount of either products or reactants can be increased. Refining is carried out in
three main steps.

Step 1 - Separation
The oil is separated into its constituents by distillation, and some of these components (such as
the refinery gas) are further separated with chemical reactions and by using solvents which
dissolve one component of a mixture significantly better than another.

Step 2 - Conversion
The various hydrocarbons produced are then chemically altered to make them more suitable for
their intended purpose. For example, naphthas are "reformed" from paraffin sand naphthenes into
aromatics. These reactions often use catalysis, and so sulfur is removed from the hydrocarbons
before they are reacted, as it would 'poison' the catalysts used. The chemical equilibria are also
manipulated to ensure a maximum yield of the desired product.

Step3 - Purification
The hydrogen sulfide gas which was extracted from the refinery gas in Step 1 is converted to
sulfur, which is sold in liquid form to fertiliser manufacturers.

PROCESS UNIT DESCRIPTION

ATMOSPHERIC AND VACUUM DISTILLATION UNIT

THE UNIT CONSISTS OF FOUR SECTIONS:
Section 1: Crude Oil Desalting
Section 2: Prefractionator column and Stabilisation of Naphtha.
Section 3: Atmospheric Distillation of Crude oil.
Section 4: Vacuum Distillation of Reduced Crude oil.

1.1. STREAM DAYS: 345 days per year.

1.2. TYPES OF CRUDE:

Low Sulfur Indian : Bombay high.
Nigerian: Girasol, Escravos, Farcados, Bonny light
High Sulfur
Imported: Arab Mix, Kuwait, Dubai, Ratawi, Basra etc.

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1.3. PRODUCTS OF AVU
The unit is to produce the following products designated by T.B.P. cuts also:-

Product Use / Using secondary units

Stream
LPG Feed sent to merox unit treatment.

C5 - 120 °C Naphtha Component

cut
C5 - 118 °C cut CCRU / NSU

120 - 135 °C Heavy Naphtha for blending with Diesel

cut (BH)

118 - 142 °C
cut (AM) Can be used as Naphtha component

135 - 255 °C Used as Superior kerosene

cut (BH)

142 - 255 °C Sent as ATF to MEROX for treatment

cut (AM)

255 - 296 °C Used as Superior kerosene

cut (BH)

255 - 300 °C Used as Cutter stock / HSD component

cut (AM)

296 - 325 °C HSD component (Light Gas Oil)

cut (BH)

300 - 330 °C
cut (AM)

325 - 380 °C HSD component (Heavy Gas oil)

cut (LS)

330 - 386 °C HVGO component

cut (AM) (Heavy Atmospheric Gas Oil)

Light Vacuum HSD component

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 Gas Oil
(<380 °C cut )

380 - 425 °C Light Diesel Oil

cut (also HVGO component)

425 - 530 °C Heavy Vacuum Gas Oil

cut Used as OHCU / FCCU feed

Vacuum Slop Blended with SR for VDU feed

Atmospheric Used as IFO component in LS run

Residue
RCO

Vacuum Feed for BBU in AM run

Residue
SR Feed/Hot feed for VBU in all runs

IFO component in LS run

1.5. PROCESS DESCRIPTION AND PRODUCT ROUTING

ATMOSTPHERE DISTILLATION UNIT :

The ADU (Atmospheric Distillation Unit) separates most of the lighter end products such as gas,
gasoline, naphtha, kerosene, and gas oil from the crude oil. The bottoms of the ADU are then
sent to the VDU (Vacuum Distillation Unit). Crude oil is preheated by the bottoms feed
exchanger, further preheated and partially vaporized in the feed furnace and then passed into the
atmospheric tower where it is separated into off gas, gasoline, naphtha, kerosene, gas oil and
bottoms.
Atmospheric and Vacuum unit (AVU) of Mathura Refinery is designed to process 100% Bombay
High Crude and 100% Arab Mix crude (consisting of Light and Heavy crude in 50:50 proportion
by weight). Crude is received from the tank and is pumped through a series of heat
exchangers(1st stage preheat) before sending it to desalters.In desalters, salts bottom sediments
and water are removed from crude by injecting water and separating out brine with the help of
electrodes. This desalted crude is then passed through another chain of exchangers(2nd stage
preheat).After that crude is sent to prefractionator column where IBP- 1000 C, IBP – 110 o C cut
naphtha product BH and AM operation respectively, is recovered from crude oil in the
prefractionator column as overhead product whereas topped crude from bottom is sent another

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chain of exchangers(3rd stage preheat).The topped crude is heated further in furnaces. This
heated crude is sent to atmospheric distillation column where fractionation of crude is sent into
different products takes place. Column profile is maintained by regulating CRs. Different
parameters are maintained to maintain product quality.

1.5.1. VACUUM DISTILLATION UNIT:

Bottom residue of (Atmospheric Distillation Column)is again processed in vacuum column to
increase distillate yield(and profitability).
RCO from bottom of ADU is heated further in vacuum furnace before processing it in (Vacuum
Distillation Column). In vacuum column, pressure is maintained at around 60 mmHg at column
top pressure using ejectors. Fractionation of RCO into different products under reduced pressure
takes place. Different parameters are maintained to adjust and control the product quality.
The finished products are then sent to storage tanks before extracting heat in heat exchangers,
which can be used for crude preheating .

1.6. PROCESS FLOW DESCRIPTION

1.6.2. SYSTEM DESCRIPTION:
Crude Oil is heated up to 136 -141 ºC in the first train of heat exchangers operating in two
parallel sections up to the desalter which is connected in series. Desalting temperature as
required can be maintained manually by operating the bypass valve of heat exchangers.

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A two-stage desalter has been designed for 99% salt removal. It is designed to use stripped sour
water for desalting which is being taken ex stripped sour water unit.
1.7. FURNACE OPERATION:
CDU Fired Heater
VDU Fired Heater
1.7.1. CDU Fired Heater:
The convection section has 8 rows of tubes with 8 nos. tubes in each. The two rows of shock
tubes, i.e. the two rows just above the radiant section are plain tubes without studs. The rest six
rows are of extended surface type having cylindrical studs. Crude oil to be heated enters the
convection section in four passes. Then it passes through crossovers provided inside the furnace
into bottom coils of the radiant section. Steam flow is of single pass to superheating coils.
1.7.2. VDU Fire Heater:
Like any conventional process heater, these heaters are also having two distinct heating sections:
(I) a radiant section, and (ii) convection section.
The convection section has 13 rows of tubes with 8 nos. tubes in each. The top three rows are for
.
of superheating LP steam for vacuum column and the rest 10 rows are for RCO The skin
temperature of tubes is limited to 542 0 C.
The furnaces are of balanced draft type with forced draft (FD) fans to supply combustion air and
induced draft (ID) fan to take suction of the flue gases through air-preheating system and
discharge the same to stack.

1.8. CRUDE DISTILLATION UNIT:

The column is provided with 56 trays of which 8 are baffle trays in the stripping section. Heated
and partly vaporized crude feed coming from fired heater enters the flash zone of the column at
tray no. 46 at 355 ºC Hydrocarbon vapors flash in this zone and get liberated. Non-flashed
liquid moves down which is largely bottom product, called RCO.
Reduced crude oil product is collected at the bottom of the column and the overhead vapors are
totally condensed in Overhead air Condenser and train condenser. This condensed overhead
product is separated as hydrocarbon and water in the reflux drum.

1.9 . VACUUM DISTILLATION UNIT:

Hot RCO from the atmospheric column bottom at 355 ºC is mixed with slop recycle from
Vacuum Column, heated and partially vaporized in 8-pass vacuum furnace and introduced to the
flash zone of the vacuum column. The flash zone pressure is maintained at 115-120 mm of Hg.
Steam (MP) is injected into individual passes and regulated manually. Three injection points
have been provided on each pass. This is to maintain required velocities in the heater, which is
Fuel Gas, Fuel Oil or combination fuel fired. Each cell is provided with 10 burners fired
vertically upshot from furnace floor along the centerline of the cell.

16
 The hydrocarbon vapors are condensed in the HVGO, LDO and LVGO sections by circulating
refluxes to yield the side draw products. Vacuum is maintained by a two-stage ejector system
with surface condensers.
FLUID CATALYTIC CRAKING UNIT (FCCU)

In this process Heavy Gas Oil cut (Raw Oil) from Vacuum Distillation Section of AVU is
catalytically cracked to obtain more valuable light and middle distillates. The present processing
capacity of the unit is about 1.48 MMT/Yr. It consists of the following sections:
Catalytic section, ● Fractionation section and
Gas concentration section.
The unit is designed to process two different types of feed i.e. Arab Mix HVGO, Bombay High
HVGO.
2.1. CRACKING SECTION

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Cracking process uses high temperature to convert heavy hydrocarbons into more valuable

lighter products. This can be accomplished either thermally or catalytically. The catalytic process
has thermal cracking in which the catalyst helps the reactions to take place at lower pressures
and temperatures. At the same time, the process produces a higher octane gasoline, more stable
cracked gas and less of the undesirable heavy residual product. The process is also flexible in
that it can be tailored to fuel oil, gas oil operations producing high yields of cycle oils or to LPG
.
operations producing yields of C3-C4 fraction
The fluid Catalytic Cracking process employs a catalyst in the form of minute spherical particles,
which behaves like a fluid when aerated with a vapour. This fluidized catalyst is continuously
circulated from the reaction zone to the regeneration zone. The catalyst also transfers heat carried
with it from one zone to the other through pipes in the vessels reactor and regenerator. The
reaction and regeneration zones form the heart of the catalytic cracking unit.
Catalyst section consists of the reactor of the reactor and regenerator, which together with the
standpipes and riser form the catalyst circulation circuit. The catalyst circulates up the riser to
the reactor, down through the stripper to the, regenerator across to the regenerator standpipe and
back to the riser. The vertical riser is in fact the reactor in which the entire reaction takes place.
The reactor is a container for cyclone separators at the end of vertical riser.
Coke is deposited on the catalyst in the reaction zone. The spent catalyst flows downwards into
the stripping section of the reactor. After steam stripping to remove oil vapours from it the
catalyst flows from the reactor standpipe to the regenerator through a slide valve in the
regenerator, the coke is burnt off, oxygen for burning being supplied by an air blower. Air from
the blower is uniformly given to the regenerator through a pipe grid at its bottom. The heat of
combustion raises the catalyst temperature to more than 600 (C. Most of the heat in the catalyst
is given to the feed in the reactor riser to raise it to the reaction temperature and to provide the
heat of reaction. The regenerated catalyst from the standpipe flows into the riser through a slide
valve to complete the catalyst circulation cycle. Catalyst particles in the flue gas leaving the
regenerator are separated at the top of regenerator by three sets of two-stage cyclones. The flue
gas contains both CO and CO2 as carbon is burnt off partly to CO and partly to CO2 in the

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regenerator. The sensible and chemical heat in flue gas is utilized to generate steam in CO
Boiler. The flue gas is passed through' the orifice chamber & regenerator. Pressure is controlled
by double disc slide valve. Orifice chamber holds back pressure downstream of double-disc
slide valve.
2.3. Type of catalyst
The unit requires two types of catalyst, viz.
Fresh catalyst
Equilibrium catalyst

2.4. FRACTIONATION SECTION

In this section, the vapors coming out of the reactor top at very high temperature are fractionated
into wet gas and un-stabilized gasoline overhead products, heavy naphtha, and light cycle oil as
side products. Heavy cycle oil drawn from the column is totally recycled along with the feed
after providing for the recycle stream to the column.
The column bottom slurry containing a small quantity of catalyst is sent to a slurry settler. From
the settler bottom, the thickened slurry is recycled back to the riser for recovering catalyst is sent
to a settler and from the settler bottom, the thickened slurry is recycled back to the riser for
recovering catalyst and further cracking. From the top of slurry settler, clarified oil product is
taken out after cooling which goes for blending in Fuel Oil.

VIS - BREAKER UNIT Introduction:

The Visbreaker Unit is designed for processing a mixture of Atmospheric and Vacuum Residue
from 1:1 mixture of Light Arabian and North Rumaila Crudes. It reduces the viscosity and pour
l.
point of heavy petroleum fractions so that product can be sold as fuel oi
Following table summaries shows the mode of operation in VBU and their feed streams.
Feed Stream Design
Capacity,MMTPA
Atmospheric 400
Residue
Vacuum Residue 600

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THEORY OF VISBREAKING

The Visbreaker is essentially a Thermal cracking unit designed to operate at mild conditions and
to retain all the cracked light oils in the bottom product. This results in reduction of viscosity of
bottom product. In the Thermal cracking reaction, heavy oil is kept at a high temperature for a
certain amount of time and this causes the larger molecules to break up. The resulting product
has a random distribution of molecular sizes resulting in products ranging from light gas to
heavy gas oil. These products are characterized as "Cracked" products and contain a certain
percentage of olefinic compounds. Whenever a molecule breaks one of the resulting molecules is
an olefin.

CH3- CH2- CH2- CH2- CH2- CH2- CH3CH 3- CH2- CH=CH2 + CH3- CH2- CH3

Cracked products are unstable and form gum. The cracked naphtha has higher octane number
than straight run gasoline. During the cracking operation, some coke is usually formed. Coke the
end product of polymerizations reaction in which two large olefin molecules combine to form an
even larger olefinic molecule.

C10H 21- CH=CH2 + CH 2= CH-C10H 21C 10H 21- CH=CH-CH2- CH2- C10H 21

Vis-breaker Furnaces

Vis-breaker unit is provided with two identical natural draft furnaces. They are up-right steel
structures with outer steel casing lined with refractory material. Each of the furnaces is
independent with radiation section at the bottom. Convection section is at the top of the radiation
section and above convection section is the stack. The convection further heat from the flue
gases leaving the radiation section. It is having numbering 6, 10 and 14 respectively.

The radiation section houses the radiation tubes numbering 30 in each pass. In this section heat is
transferred primarily by radiation by flame and hot combustible gases.
VBU furnace tubes skin temperature is measured by skin thermocouples provided on tubes in
radiation zone. Furnaces are provided with thermocouple in radiation and convection zones for
measuring tube skin temperatures, box temperatures before and after steam coils, and flue gas to
stack temperatures. Thermocouples are also provided inside furnace tubes for measuring liquid
temperatures at different points. The maximum allowed tubes skin and box temperature in the
heaters is 650 oC and 750 oC respectively.
There is a provision for on-stream analyzer of SO 2 emission from both the stacks. The purpose of
the water, injection is to maintain suitable velocity in the furnace tubes and to minimize coking.

V.B. FRACTIONATOR

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Soaker effluent after quenching enters fractionator. Temperature in the flash zone is around 420
oC. From the column, gas & gasoline are separated as overhead, gas oil as side stream and the
VB tar as bottoms. The fractionator has 26 valve trays and one blind tray. Feed enters flash zone
below the 26th Valve tray.The overhead vapours from the column are condensed and cooled in
heat exchangers.
The liquid vapour mixture is separated in the reflux drum. Gasoline from flash fractionator is
picked up by reflux pumps and partly pumped to column top as reflux. The remaining gasoline is
routed to stabilizer under reflux drum level controller, which is cascaded with flow controller.
The sour water is drained from the drum boot under interface level controller and routed to sour
water stripper. Main reflux drum and its water boot are having level glasses.

One stream is used as heating media in steam generator where it is cooled from 260 o C to 214 o
C. The second stream supplies re-boiling heat to stabilizer re-boiler and gets cooled from 260 oC
to 215 o C. To protect column bottom against coking, cooled VB tar condensed in air cooler and
go to reflux drum. Safety valve is provided to release gas and protect the vessel from over
pressure.
Tar is cooled from 351 o C to 225 o C in feed exchangers and further cooling to 214 o C is done.
Pumps are having two filters in the suction line with gas oil flushing facilities. Only one filter is
kept in service while the other remains as spare. Cooled VB tar is partly used as quench to
Fractionator column bottom. Bottom temperature is maintained at 355 o C.
Transfer lines of the two furnaces. Temperature of the combined effluent entering main
fractionator is maintained at 427 o C.
Gas oil stripper bottom should be protected against coking. Bottom temperature is maintained at
351 o C.
VB tar is then cooled in boiler feed water exchanger from 232 o C to 210 o C. It is further cooled
to 90 o C and sent to storage with gas oil.

Stabilizer
Un-stabilized gasoline from reflux drum is picked up by reflux pump and then it is pumped to
stabilizer through stabilized gasoline exchanger. In heat exchanger, feed is heated from 43 oC to
120 oC while stabilized gasoline is cooled from 180 oC to 120 oC. The column has 30 trays and
the feed enters on the 19th.The overhead product at 60 oC goes to water condensers. The
condensed liquid is collected in the reflux drum. Uncondensed gas from the drum goes to
FCC/unit fuel gas header. Pressure at the drum is maintained at 8.4kg/cm2 (g).

to the first reactor. Each reactor is a vertical cylindrical vessel with spherical heads

21
PROJECT- I
Calculation of Furnace Efficiency

FURNACE
Furnace is a heating system. Furnace is called direct fired heater. There are three types of
furnace-

● Fuel combustion furnace. ● Electric Arc furnace.

● Industrial Furnace

FURNACE COMPONENT

Burners , Heat exchangers, Draft inducer and venting

Controls and safety devices
Blower and air movement

INDUSTRIAL FURNACE-

An industrial furnace or direct fired heater is equipment used to provide heat or can serve as
reactor which provides heats of reaction. Furnace designs vary as to its function, heating duty,
type of fuel and method of introducing combustion air; however, most process furnaces have
some common features.

Fuel flows into the burner and is burnt with air provided from an air blower. There can be more
than one burner in a particular furnace which can be arranged in cells which heat a particular
set of tubes. Burner can also be floor mounted, wall mounted or roof mounted depending on
design. The flame heat up the tubes, which in turn heat the fluid inside in the first part of the
furnace known as the radiant section or firebox. In this chamber where combustion takes place,
the heat is transferred by radiation to tubes around the fire in the chamber. The heating fluid
passes through the tubes and is thus heated to the desired temperature. The gases from the
combustion are known as flue gases. After the flue gas leave the firebox, most furnace designs

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include a convection section where more heat is recovered before venting to the atmosphere
through the flue gas stack

Fuel flows into the burners and air flows from air blowers for burning.

There are tubes in the furnace. Flames heat up the tubes.

There are two sections in the furnace-

● Radiation section.
● Convection section

Radiation Section-
This is first part of the furnace. This is also called firebox. Combustion takes place in this
section. Heat is transferred mainly by radiation gases from combustion of flue gases. The
radiation section is where the tubes receive almost all its heat by radiation from the flame. In
the vertical cylindrical furnace the tubes are vertical. Tubes can be vertical or horizontal, placed
along the refractory wall, in the middle etc.or arranged in cells. Studs are used to hold the
insulation together and on the wall of furnace. The tubes are distant away from the insulation
so radiation can be reflected to the back of the tubes to maintain a uniform tube wall
temperature. Tube guides at the top, middle and bottom hold the tubes in place.

Convection Section-
Convection Section is next to radiation section where it is cooler to recover additional heat.
Heat transfer takes place by convection here. And tubes are finned to increase heat transfer. The
tubes (without fins)located at the top of the radiation section are known as shield section, so
named because they are still exposed to plenty of radiation from the firebox and they also act to
shield the convection section tubes, which are normally of less resistant material from the high
temperatures in the firebox.. The area of the radiant section just before flue gas enters the
shield section and into the convection section called bridge zone. Crossover is the term used to
describe the tube that connects from the convection section outlet to the radiant section inlet.
The crossover piping is normally located outside so that the temperature can be monitored and
the efficiency of the convection section can be calculated. The slight glass at the top allows
personnel to see the flame shape and pattern from above and visually inspect if flame

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impingement is occurring. Flame impingement happens when the flame touches the tubes and
causes isolated spots of very high temperature.

Burner-
The burner in the vertical, cylindrical furnace as above is located in the floor and fires upward.
Some features have side fired burners. The burner tile is made of high temperature refractory
and is where the flame is contained. Air registers located below the burner and at the outlet of
the air blower are devices with movable flaps or vanes that control the shape and pattern of the
flame, whether it spreads out or even swirls around. Flames should not spread out too much, as
this will cause flame impingement. Air register is classified as primary, secondary and if
applicable tertiary, depending on when their air is introduced. The Primary air register supplies
primary air, which is the first to be introduced in the burner. Secondary air is added to
supplement primary air. Burners may include a premix to mix the air and fuel for better
combustion before introducing into the burner. Some burners even use steam as premix to
preheat the air and create better mixing of the fuel and heated air. The floor of furnace is mostly
made of a different material from that of the wall, typically hard castable refractory to allow
technicians to walk on its floor during maintenance.

FURNACE EFFICIENCY-

Furnace efficiency measures the amount of heat produced compared to the amount of fuel burned
the percentage of fuel that a furnace turns into actual heat is called Annual fuel utilization
efficiency (AFUE). A furnace is then labeled as low-minded or high efficiency. Low efficiency
models under 78% , are older, and not generally for sale. Mid efficiency models start at 78% and
go up to 90% AFUE. Anything above the level is considered high efficiency.

Calculation for furnace efficiency-

Efficiency (ɳ) = (Heat input / Heat output) *100

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Heat Input = (Mass flow rate of fuel oil/through put) *(specific heat of fuel

oil) * (Temperature difference between heat in convection zone

inlet and stack outlet)

Heat Output = Fire duty * G.C.V (Gross calorific value)

● Mass flow rate of fuel oil/ throughput = 1st inlet + 2nd inlet + 3 inlet
= 77510 kg/h
● Specific heat of fuel oil = 0.8245 Kcal/Kg ͦC

● Temperature at convection zone inlet = 518.7 ͦC

● Temperature at heat stack outlet = 405.59 ͦC

● Fuel Oil Fire duty = 1050 Kg/hr

● G.C.V (Gross calorific value) = 9737.8 Kcal/Kg

● Heat input = (77510)* (0.8245)* (518.7 – 405.59) = 7228520.2

● Heat output = (1050) * (9737.8) = 10224690

● Efficiency (ɳ) = {(7228520.2)/(10224690)} * 100

= 70.69 %

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CONCLUSION

Thus Indian oil cooperation is one of the leading economy of India and it sustain a livelyhood of
thousands of employees . Considering the need of situation it is continously improving the
quality of its product taking into account the evironmental issues . IOCL Mathura is the first to
produce BS-VI grade petrol and had patented it . it leads to a SO2 emmission less than 5 ppm. It
is high grade petrol of premium quality and is currently being used in national capital delhi . It is
good for evironment as well as for engine. Their is continous research work being done in
laboratries to improve the product and the 70% criteria of green belt is being fulfilled.

Refrences
Dr. Ramprasad, Petroleum Refining Technology en.wikipedia.org www.britannica.com www.iocl.com
www.kbr.com

Guide to Refining from Chevron Oil's website

Behind high gas prices: The refinery crunch

Gary, J.H. and Handwerk, G.E. (1984). Petroleum Refining Technology and Economics (2nd Edition ed.).

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