This document is a summer training report submitted by Mohan Bihari to his coordinator at his university. It provides an overview of his summer training experience at the Indian Oil Corporation Ltd. refinery in Barauni, Bihar, India. The report includes sections on various pumps used at the refinery like centrifugal pumps and screw pumps. It also discusses concepts like net positive suction head, cavitation, and different types of valves. The report aims to provide insights gained from his practical training experience at the refinery.
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SUMMER TRAINING REPORT
Indian Oil Corporation Ltd,Barauni
Submitted to: Submitted By:
Mr. M L RINAWA MOHAN BIHARI
Coordinator-Practical Training Seminar 12EEJME029
In partial fulfilment of requirements for the degree of
BACHELOR OF TECHNOLOGY
IN
MECHANICAL ENGINEERING
GOVERNMENT ENGINEERING COLLEGE JHALAWAR
RAJASTHAN, INDIA
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PREFACE
Industrial training plays a vital role in the progress of future engineers. Not only does it
provide insights about the industry concerned, it also bridges the gap between theory and
practical knowledge. I was fortunate that I was provided with an opportunity of undergoing
industrial training at INDIAN OIL CORPORATION LTD. BARAUNI. The experience
gained during this short period was fascinating to say the least. It was a tremendous feeling to
observe the operation of different equipments and processes. It was overwhelming for us to
notice how such a big refinery is being monitored and operated with proper coordination to
obtain desired results. During my training I realized that in order to be a successful
mechanical engineer one needs to possess a sound theoretical base along with the acumen for
effective practical application of the theory. Thus, I hope that this industrial training serves as
a stepping stone for me in future and help me carve a niche for myself in this field.
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ACKNOWLEDGEMENT
My indebtedness and gratitude to the many individuals who have helped to shape this report
in its present form cannot be adequately conveyed in just a few sentences. Yet I must record
my immense gratitude to those who helped me undergo this valuable learning experience at
IOCL Barauni.
I am highly obliged to Mrs. Krishna Kumari, Training and Development Department for
providing me this opportunity to learn at IOCL. I thank Shri Anand Prakash, Chief Manager
(Maintenance Department) for guiding me through the whole training period. I express my
heartiest thanks to Shri Sirajuddin Ahmed, for sharing his deep knowledge about various
pumps and other equipments in workshop. I would also like to thank Mr. Samir Das in valve
section for explaining us about different valves and their repairing. My special thanks to the
SPM Instruments team for the on field experience of vibration testing of equipments and Shri
Sanjay Lamba for showing us detailed procedure of analysis of vibrations.
I am grateful to Mr. Manoj Mittal, HOD Mechanical Engineering Branch,GECJ for his help
and guidance about this project.
Last but not the least I am thankful to Almighty God, my parents, family and friends for their
immense support and cooperation throughout the training period.
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INTRODUCTION
Petroleum is derived from two words – “petro” means rock and “oleum” means oil.
Thus the word “petroleum” means rock oil. This is a mixture of hydrocarbons; hence it
cannot be used directly and has got to be refined. Petroleum is refined in petroleum
refinery.
Indian Oil Corporation Ltd. (IOC) is the flagship national oil company in the
downstream sector. The Indian Oil Group of companies owns and operates 10 of India's
19 refineries with a combined refining capacity of 1.2 million barrels per day. These
include two refineries of subsidiary Chennai Petroleum Corporation Ltd. (CPCL) and
one of Bongaigaon Refinery and Petrochemicals Limited (BRPL). The 10 refineries are
located at Guwahati, Barauni, Koyali, Haldia, Mathura, Digboi, Panipat, Chennai,
Narimanam, and Bongaigaon.
Indian Oil's cross-country crude oil and product pipelines network span over 9,300 km.
It operates the largest and the widest network of petrol & diesel stations in the country,
numbering around 16455. Indian Oil Corporation Ltd. (Indian Oil) was formed in 1964
through the merger of Indian Oil Company Ltd and Indian Refineries Ltd. Indian
Refineries Ltd was formed in 1958, with Feroze Gandhi as Chairman and Indian Oil
Company Ltd. was established on 30th June 1959 with Mr S. Nijalingappa as the first
Chairman.
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BARAUNI REFINERY
Barauni Refinery has doubled its refining capacity from 6 MMT/yr to 12 MMT/yr with the
commissioning of its Expansion Project. Barauni Refinery is the seventh refinery of Indian
Oil. It is located in the historic district of Barauni in the state of Bihar and is about 2 km from
Barauni City. The original refinery with 6 MMTPA capacity was built and commissioned in
1994 at a cost of Rs. 3868 crore (which includes Marketing Pipelines installations).
The major secondary processing units of the Refinery include Catalytic Reforming Unit,
Once through Hydrocracker unit, Resid Fluidised Catalytic Cracking unit, Visbreaker unit,
Bitumen blowing unit, Sulphur block and associated Auxiliary facilities. In order to improve
diesel quality, a Diesel Hydro Desulphurization Unit (DHDS) was subsequently
commissioned in 1999.
Referred as one of India’s most modern refineries, Barauni Refinery was built using global
technologies from IFP France; Haldor-Topsoe, Denmark; UNOCAL/UOP, USA; and Stone
&Webster, USA. It processes a wide range of both indigenous and imported grades of crude
oil. It receives crude from Vadinar through the 1370 km long Salaya-Mathura Pipeline which
also supplies crude to Koyali and Mathura Refineries of Indian Oil.
Petroleum products are transported through various modes like rail, road as well as
environment-friendly pipelines. The Refinery caters to the high-consumption demand centers
in North-Western India including the States of Haryana, Punjab, J &K, Himachal,
Chandigarh, Uttaranchal, as well as parts of Rajasthan and Delhi.
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PUMPS
A pump is a device that moves fluids or sometimes slurries by mechanical action. Pumps can
be classified into three major groups according to the method they use to move the fluid:
direct lift, displacement, and gravity pumps.
Pumps operate via many energy sources and by some mechanism (typically reciprocating or
rotary), and consume energy to perform mechanical work by moving the fluid by manual
operation, electricity, engine or wind power.
Common Pumps Used In IOCL
1. Centrifugal Pumps
A centrifugal pump is a pump that consists of a fixed impeller on a rotating shaft that is
enclosed in a casing, with an inlet and a discharge connection. As the rotating impeller swirls
the liquid around, centrifugal force builds up enough pressure to force the water through the
discharge outlet. This type of pump operates on the basis of an energy transfer, and has
certain definite characteristics which make it unique. The amount of energy which can be
transferred to the liquid is limited by the type and size of the impeller, the type of material
being pumped, and the total head of the system through which the liquid is moving.
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Centrifugal pumps are designed to be used as a portable pump, and are often referred to as a
trash pump. It is named so because the water that is being pumped is not clean water. It is
most often water containing soap or detergents, grease and oil, and also solids of various
sizes that are suspended in the water.
The major types of centrifugal pumps used in the refinery are:
1. Vertical CantileverPump
It is a specialized type of vertical sump pump designed to be installed in a tank or sump but
with no bearing located in the lower part of the pump. Thus, the impeller is cantilevered from
the motor, rather than supported by the lower bearings.
A cantilever pump is considered a centrifugal pump configured with the impeller
submerged in the fluid to be pumped. But unlike a traditional vertical column sump
pump, there are no bearings below the motor supporting the impeller and shaft.
The cantilever pump has a much larger diameter shaft, since it has no lower sleeve
bearings that act to support the impeller and shaft.
In general, cantilever pumps are best for relatively shallow sumps, usually around 8 to
10 feet maximum. This is because the deeper the sump, the larger the shaft diameter
that is required to cantilever the impeller.
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2. Split Case Pumps
This type of pump has a split casing at the suction side. It prevents the turbulence and
formation of eddies at inlet.
Split Case pumps are designed to pump clean water or low viscosity clean liquids at
moderate heads more economically, which is widely used for liquid transfer and
circulation of clean or slightly polluted water. And the typical applications are
Municipal water supply, Power plants, Industrial plants, Boiler feed and condensate
systems, Irrigation and dewatering and marine service.
Advantages:
Less noise and vibration, suitable to a lifting speed working condition.
Inverted running is available for the same rotor, the risk of water hammer is lower.
Unique design for high temperature application up to 200 ℃, intermediate support,
thicker pump casing, cooling seals oil lubrication bearings.
Vertical or horizontal with packing seal or mechanical seal can be designed according
to the different working condition.
Beautiful outline design.
Specifications ofa Centrifugal Pump in Refinery
Offered Capacity: 317 LPM
RPM: 1450
Efficiency: 93%
Mounting: Horizontal
Sealing: Mechanical Seal
Power Rated: 7 KW
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Applications of Centrifugal Pump in Barauni Refinery
For circulation of cooling water.
For pump the fluid (crude oil, VGO, diesel etc.) in reactors, coulombs etc. with high
pressure.
In liquid storage tanks
Net Positive SuctionHead (NPSH) Overview
Net Positive Suction Head (NPSH) NPSH Available is a function of the system in which the
pump operates. It is the excess pressure of the liquid in feet absolute over its vapor pressure
as it arrives at the pump suction. In an existing system, the NPSH Available can be
determined by a gauge on the pump suction.
The Hydraulic Institute defines NPSH as the total suction head in feet absolute, determined
at the suction nozzle and corrected to datum, less the vapor pressure of the liquid in feet
absolute. Simply stated, it is an analysis of energy conditions on the suction side of a pump
to determine if the liquid will vaporize at the lowest pressure point in the pump.
The pressure which a liquid exerts on its surroundings is dependent upon its temperature.
This pressure, called vapor pressure, is a unique characteristic of every fluid and increased
with increasing temperature. When the vapor pressure within the fluid reaches the pressure of
the surrounding medium, the fluid begins to vaporize or boil. The temperature at which this
vaporization occurs will decrease as the pressure of the surrounding medium decreases.
A liquid increases greatly in volume when it vaporizes. One cubic foot of water at room
temperature becomes 1700 cu. ft. of vapor at the same temperature.
It is obvious from the above that if we are to pump a fluid effectively, we must keep it in
liquid form. NPSH is simply a measure of the amount of suction head present to prevent
this vaporization at the lowest pressure point in the pump.
NPSHcan be defined as two parts:
NPSH Available (NPSHA): The absolute pressure at thesuction port of the pump.
NPSH Required (NPSHR): The minimum pressure required atthe suction port of the
pump to keep the pump from cavitating.
NPSHA is a function of your system and must be calculated, whereas NPSHR is a function
of the pump and must be provided by the pump manufacturer. NPSHA must be greater than
NPSHR for the pump system to operate without cavitating. Thus, we must have more
suction side pressure available than the pump requires.
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CAVITATION
Cavitation is a term used to describe the phenomenon, which occurs in a pump when there is
insufficient NPSH Available. When the pressure of the liquid is reduced to a value equal to
or below its vapor pressure the liquid begins to boil and small vapor bubbles or pockets
begin to form. As these vapor bubbles move along the impeller vanes to a higher pressure
area above the vapor pressure, they rapidly collapse.
The collapse or "implosion" is so rapid that it may be heard as a rumbling noise, as if you
were pumping gravel. In high suction energy pumps, the collapses are generally high enough
to cause minute pockets of fatigue failure on the impeller vane surfaces. This action may be
progressive, and under severe (very high suction energy) conditions can cause serious pitting
damage to the impeller.
Cavitation is often characterized by:
Loud noise often described as a grinding or “marbles” in the pump.
Loss of capacity (bubbles are now taking up space where liquid should be
Pitting damage to parts as material is removed by the collapsing bubbles
Vibration and mechanical damage such as bearing failure
Erratic power consumption
The way to prevent the undesirable effects of cavitation in standard low suction energy
pumps is to insure that the NPSH Available in the system is greater than the NPSH
required by the pump.
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Screw Pumps
Main Elements of Screw Pump Design
The pumping element of a two screw pump consists of two intermeshing screws rotating
within a stationary bore/housing that is shaped like a figure eight.The rotor and housing/body
are metal and the pumping element is supported by the bearings in this design.The clearances
between the individual areas of the pumping screws are maintained by the timing gears.When
a two screw pump is properly timed and assembled there is no metal-to-metal contact within
the pump screws.
The pumping screws and body/ housing can be made from virtually any machinable alloy.
This allows the pump to be applied for the most severe applications in aggressive fluid
handling. Hard coatings can also be applied for wear resistance.The stages of the screw are
sealed by the thin film of fluid that moves through the clearances separating them.Finally, in
a two screw design, the bearings are completely outside of the pumped fluid. This allows
them to have a supply of clean lubricating oil and be independent of the pumped fluid
characteristics. The external housings also allows for cooling which means the quality of the
lube oil can be maintained in high temperature or horsepower applications.
Working
These pumps are based on the basic principle where a rotating cavity or chamber within a
close fitting housing is filled with process fluid, the cavity or chamber closes due to the rotary
action of the pump shaft(s), the fluid is transported to the discharge and displaced, this action
being accomplished without the need for inlet or outlet check valves.
Specifications ofa Screw Pump
Name: Emergency Lube Oil Pump
Driver: Electric Motor
Liquid Handled: Lube Oil
Pumping temperature: 65oC
Specific Gravity: 0.88
Rated Capacity: 237 LPM
Suction Pressure: Atmospheric
Discharge Pressure: 10 Kg/cm2
NPSH available: 10 m
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Applications
Used where high pressure is needed.
Mostly used for high viscous fluid.
Pump Selectionon basis of Process Parameters
Selecting between a Centrifugal Pump or a Positive Displacement Pump is not always
straight forward. Following factors are considered while selecting a pump.
1. Flow Rate and Pressure Head
The two types of pumps behave very differently regarding pressure head and flow rate:
The Centrifugal Pump has varying flow depending on the system pressure or head. The
Positive Displacement Pump has more or less a constant flow regardless of the system
pressure or head. Positive Displacement pumps generally give more pressure than
Centrifugal Pumps.
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2. Flow and Viscosity
In the Centrifugal Pump the flow is reduced when the viscosity is increased.In the
Positive Displacement Pump the flow is increased when viscosity is increased. Liquids
with high viscosity fill the clearances of a Positive Displacement Pump causing a higher
volumetric efficiency and a Positive Displacement Pump is better suited for high
viscosity applications. A Centrifugal Pump becomes very inefficient at even modest
viscosity.
3. Mechanical Efficiencyand Pressure
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Changing the system pressure or head has little or no effect on the flow rate in the Positive
Displacement Pump. Changing the system pressure or head has a dramatic effect on the
flow rate in the Centrifugal Pump.
4. Mechanical Efficiency and Viscosity
Viscosity also plays an important role in pump mechanical efficiency. Because the centrifugal
pump operates at motor speed efficiency goes down as viscosity increases due to increased
frictional losses within the pump. Efficiency often increases in a PD pump with increasing
viscosity. Note how rapidly efficiency drops off for the centrifugal pump as viscosity
increases.
5. NetPositive Suction Head–NPSH
In a Centrifugal Pump, NPSH varies as a function of flow determined by pressure. In a
Positive Displacement Pump, NPSH varies as a function of flow determined by speed.
Reducing the speed of the Positive Displacement Pump, reduces the NPSH.
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Common Problems encountered in Pumps
The types of pumps that are most commonly used in a Refinery plant are
centrifugal pumps. These pumps use centrifugal action to convert mechanical
energy into pressure in a flowing liquid. The main components of the pump
that are usually prone to problems are impellers, shafts, seals and bearings.
An important aspect of the impeller is the wear rings. If the impeller is too
close to the stationary element, the impeller or the casing will be worn out.
The other part is the shaft. It runs through the center of the pump and is
connected to the impeller at the left end.
Seal is a very important part in the pump. Seals are required in the casing area
where the liquid under pressure enters the casing.
The last main part of the pump is the bearing. The pump housing contains two
sets of bearings that support the weight of the shaft. The failures causing the
stoppage of the pumps are primarily experienced by these parts and will be
termed as failure modes.
There are 12 major failure modes (bad actors) for the most pumps. The
following is the definition adopted to characterize the various modes of
failure:
♦Shaft: The pump failed to operate because of shaft problem, suchas misalignment,
vibration, etc.
♦ Suction Valve: A failure due to something wrong with the pumpsuction, such a
problems in valve, corroded pipes or slug accumulated in the suction.
♦ Casing: A failure due to defective casing, such as misalignment orcorrosion.
♦ Operation Upset: Failure of a pump due to operational mistakes,such as closing
a valve which should not be closed.
♦ Coupling: A failure due to coupling distortion or misalignment.
♦ Gaskets: A failure due to a gasket rupture or damage caused byleaks.
♦ Control Valve: A failure due to malfunction of the control valve due topressure
or flow in the line of service.
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VIBRATIONS
FUNDAMENTALS OF VIBRATION
Most of us are familiar with vibration; a vibrating object moves to and fro, back and forth. A
vibrating object oscillates. We experience many examples of vibration in our daily lives. A
pendulum set in motion vibrates. A plucked guitar string vibrates. Vehicles driven on rough
terrain vibrate, and geological activity can cause massive vibrations in the form of
earthquakes. In industrial plants there is the kind of vibration we are concerned about:
machine vibration.
Machine Vibration
Machine vibration is simply the back and forth movement of machines or machine
components. Any component that moves back and forth or oscillates is vibrating
Machine vibration can take various forms. A machine component may vibrate over
large or small distances, quickly or slowly, and with or without perceptible sound or
heat. Machine vibration can often be intentionally designed and so have a functional
purpose. (Not all kinds of machine vibration are undesirable. For example, vibratory
feeders, conveyors, hoppers, sieves, surface finishers and compactors are often used
in industry.)
Almost all machine vibration is due to one or more of these causes:
(a) Repeating forces (b) Looseness (c) Resonance
(a) Repeating Forces
Repeating forces in machines are mostly due to the rotation of imbalanced,
misaligned, worn, or improperly driven machine components.
Worn machine components exert a repeating force on machine components due to
rubbing of uneven worn parts. Wear in roller bearings, gears and belts is often due to
improper mounting, poor lubrication, manufacturing defects and over loading.
Improperly driven machine components exert repeating forces on machine due to
intermittent power supply. Examples include pump receiving air in pulses, IC engines
with misfiring cylinders, and intermittent brush commutator contact in DC Motors.
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b) Looseness
Looseness of machine parts causes a machine to vibrate. If parts become loose,
vibration that is normally of tolerable levels may become unrestrained and excessive.
Looseness can cause vibrations in both rotating and non rotating machinery.
Looseness can be caused by excessive bearing clearances, loose mounting bolts,
mismatched parts, corrosion and cracked structures.
Why Monitor Machine Vibration?
Monitoring the vibration characteristics of a machine gives us an
understanding of the 'health' condition of the machine. We can use this
information to detect problems that might be developing.
If we regularly monitor the conditions of machines we will find any problems
that might be developing, therefore we can correct the problems even as they
arise. In contrast, if we do not monitor machines to detect unwanted vibration
the machines are more likely to be operated until they break down.
Below we discuss some common problems that can be avoided by monitoring machine
vibration
(a) Severe Machine Damage
(b) High Power Consumption
(c) Machine Unavailability
(d) Delayed Shipments
(e) Accumulation of Unfinished Goods
(f) Unnecessary Maintenance
(g) Quality Problems
(h) Bad Company Image
(i) Occupational Hazards
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Types of Vibration Monitoring Parameters
PRINCIPLE
Vibration amplitude may be measured as a displacement, a velocity, or acceleration.
Vibration amplitude measurements may either be relative, or absolute. An absolute vibration
measurement is one that is relative to free space. Absolute vibration measurements are made
with seismic vibration transducers.
Displacement
Displacement measurement is the distance or amplitude displaced from a resting position.
The SI unit for distance is the meter (m), although common industrial standards include mm
and mils. Displacement vibration measurements are generally made using displacement eddy
current transducers.
Velocity
Velocity is the rate of change of displacement with respect to change in time. The SI unit for
velocity is meters per second (m/s), although common industrial standards include mm/s and
inches/s. Velocity vibration measurements are generally made using either swing coil
velocity transducers or acceleration transducers with either an internal or external integration
circuit.
Acceleration
Acceleration is the rate of change of velocity with respect to change in time. The SI unit for
acceleration is meters per second2 (m/s2), although the common industrial standard is the g.
Acceleration vibration measurements are generally made using accelerometers.
Vibration Monitoring Sensors & Selections
Sensors & SensorSelection:
In industry where rotating machinery is everywhere, the sounds made by engines and
compressors give operating and maintenance personnel first level indications that things are
OK. But that first level of just listening or thumping and listening is not enough for the
necessary predictive maintenance used for equipment costing into the millions of dollars or
supporting the operation of a production facility.
The second layer of vibration analysis provides predictive information on the existing
condition of the machinery, what problems may be developing, exactly what parts may be on
the way to failure, and when that failure is likely to occur. Now, you may schedule repairs
and have the necessary parts on hand. This predictive maintenance saves money in
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faster, scheduled repairs and prevents failures that are much more expensive in terms of
repairs or lost production.
Applications
Application of these vibration sensors, with their associated equipment, provides effective
reduction in overall operatingcosts of many industrial plants. The damage to machinery
thevibration analysis equipment prevents is much more costly than the equipment and the lost
production costs can greatly overshadow the cost of equipment and testing.
Predicting problems and serious damage before they occur offers a tremendous advantage
over not having or not using vibration analysis.
Specific areas of application include any rotating machinery such as motors, pumps,
turbines, bearings, fans, and gears along with their balancing, broken or bent parts, and
shaft alignment.
The vibration systems find application now in large systems suchas aircraft, automobile,
and locomotives while they are inoperation.
Dynamic fluid flow systems such as pipelines, boilers, heatexchangers, and even nuclear
reactors use vibration analysis to find and interpret internal problems.
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VALVES
What is a valve?
A valve is a mechanical device which regulates either the flow or the pressure of the fluid. Its
function can be stopping or starting the flow, controlling flow rate, diverting flow, preventing
back flow, controlling pressure, or relieving pressure.
Basically, the valve is an assembly of a body with connection to the pipe and some elements
with a sealing functionality that are operated by an actuator. The valve can be also
complemented whit several devices such as position testers, transducers, pressure regulators,
etc.
Common Valves Used In Barauni Refinery
Gate valve
Globe valve
Ball valve
Butterfly valve
Plug valve
1. GATE VALVE
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Application In Refinery
Gate valves have an extended use in the petrochemical industry due to the fact
that they can work with metal-metal sealing.
They are used in clean flows
.
When the valve is fully opened, the free valve area coincides with area of the
pipe, therefore the head lose of the valve is small.
Limitations
This valve is not recommended to regulate or throttling service since the
closure member could be eroded. Partially opened the valve can vibrate.
Opening and closing operations are slow. Due to the high friction wear their
use is not recommend their use in often required openings. This valve requires
big actuators which have difficult automation. They are not easy to repair on
site.
2. Ball valve
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The ball valve has a spherical plug as a closure member. Seal on ball valves is excellent, the
ball contact circumferentially uniform the seat, which is usually made of soft materials
Depending on the type of body the ball valve can be more or less easily maintained. Drop
pressure relative its hole size is low.
Application in Refinery
They are used in steam, water, oil, gas, air, corrosive fluids, and can also handle slurries and
dusty dry fluids. Abrasive and fibrous materials can damage the seats and the ball surface.
Limitations
The seat material resistance of the ball valve limits the working temperature and
pressure of the valve. The seat is plastic or metal made.
Ball valves are mostly used in shutoff applications. They are not recommended to be
used in a partially open position for a long time under conditions of a high pressure
drop across the valve, thus the soft seat could tend to flow through the orifice and
block the valve movement.
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2. BUTTERFLY VALVE
The development of this type of valve has been more recent than other ones. A major
conviction on saving energy in the installations was an advantage for its introduction,
due its head loss is small. At the beginning they were used in low pressure
installations service, but technologic improvements, especially in the elastomer field
let their extension to higher performances.
As any quarter turn valve, the operative of the butterfly valve is quiet easy. The
closure member is a disc that turns only 90º; to be fully open/close.
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Advantages
Butterfly valves geometry is simple, compact and revolute, therefore it is a
cheap valve to manufacture either saving material and post mechanization. Its
reduced volume makes easy its installation. Gate and globe valves are heavier
and more complex geometry, therefore butterfly valve can result quiet
attractive at big sizes regarding other types of valves.
This is a quick operation .
Few wear of the shaft,little friction and then less torque needed means a
cheaper actuator.the actuator can be manual ,hudraulic,electric.
Application in Refinery
Butterfly valves are quite versatile ones. They can be used at multiples
industrial applications, fluid, sizes, pressures, temperatures and connections at
a relative low cost.
Butterfly valves can work with any kind of fluid, gas, liquid and also with
solids in suspension. As a difference from gate, globe or ball valves, there are
not cavities where solid can be deposit and difficult the valve operative.
Limitations
Pressure and temperature are determinant and correlated designing factors. At a constant
pressure, rising temperature means a lower performance for the valve, since some materials
have lower capacity. As well gate, globe and ball valves, the butterfly valve can be
manufactured with metallic seats that can perform at high pressure and extreme temperatures.
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4. PLUG VALVE
Plug valves have a plug as a closure member. Plug can be cylindrical or conical. Ball
valves are considered as another group despite that they are some kind of plug valve.
Plug valves are used in On/Off services and flow diverting, as they can be multiport
configured.
Advantages
They can hand fluids with solids in suspension.
Lift plug valve type are designed to rise the plug at start valveoperation, in order to separate
and protect plug-seat sealing surfaces from abrasion
Limitations
It require high maintenance cost.
Require more time for maintenance.
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5. GLOBE VALVE
A Globe valve may be constructed with a single or double port and plug arrangement. The
double port type is generally used in a CONTROL VALVE where accurate control of fluid is
required. Due to the double valve plug arrangement, the internal pressure acts on each plug in
opposition to each other, giving an internal pressure balance across the plugs.
Advantages
This gives a much smoother operation of the valve and better control of the process.
Some control valves are 'Reverse Acting'. Where a valve normally opens when the
plug rises, in the reverse acting valve, the valve closes on rising. The operation of the
valve depends on process requirements. Also depending on requirements, a control
valve may be set to open or close, on air failure to the diaphragm.
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The Globe valve is used where control of fluid flow or pressure is required and it can
be operated in any position between open and closed.
6. Non Returning Valve
A check valve may be defined simply as a mechanical device typically used to let fluid,
either in liquid or gas form, to flow through in one direction. They usually have two ports or
two openings – one for the fluid entry and the other for passing through it. Often part of
household items, they are generally small, simple, and inexpensive components.
OperationalPrincipal of Check Valve
Check valves are available with different spring rates to give particular cracking pressures.
The cracking pressure is that at which the check valve just opens. If a specific cracking
pressure is essential to the functioning of a circuit, it is usual to show a spring on the check
valve symbol. The pressure drop over the check valve depends upon the flow rate; the higher
the flow rate, the further the ball or poppet has to move off its seat and so the
There are two main types of check valve :
1. The 'LIFT' type. (Spring loaded 'BALL' & 'PISTON' Types).
2. The 'SWING' (or Flapper Type).
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SAFETYVALVES
A safety valve is a valve mechanism which automatically releases asubstance from a
boiler, pressure vessel, or other system, when the pressure or temperature exceeds
preset limits.
It is one of a set of pressure safety valves (PSV) or pressure reliefvalves (PRV), which also
includes relief valves, safety relief valves, pilot-operated relief valves, low pressure safety
valves, and vacuum pressure safety valves.
PRESSURE SAFETYVALVE OR RELIEF VALVE:
The relief valve (RV) is a type of valveused to control or limit the pressurein a system or
vessel which can build up by a process upset, instrument or equipment failure, or fire.
Schematic diagram of a conventional spring-loaded pressure relief valve.
The pressure is relieved by allowing the pressurized fluid to flow from an auxiliary passage
out of the system.
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The relief valve is designed or set to open at a predetermined set pressure to protect
pressure vesselsand other equipment from being subjected to pressures that exceed their
design limits. When the set pressure is exceeded, the relief valve becomes the "path of
least resistance" as the valve is forced open and a portion of the fluid is diverted through
the auxiliary route. The diverted fluid (liquid, gas or liquid–gas mixture) is usually routed
through a pipingsystem known as a flare header or relief header to a central, elevated flare
where it is usually burned and the resulting combustiongases are released to the
atmosphere.
It should be noted that PRVs and PSVs are not the same thing, despite what many people
think; the difference is that PSVs have a manual lever to open the valve in case of
emergency.
TEMPERATURESAFETYVALVE:
33. ~ 33 ~
Water heaters have thermostatically controlled devices that keep them from overheating
Both gas and electric water heaters have temperature-limiting devices that shut off the
energy source when their regular thermostat fails
Thermostatically controlled gas valves found on most residential gas water heaters have a
safety shutoff built into the gas valve itself. When they react to excessive temperature, the
gas flow to the burner is stopped.
PROTECTION USED IN INDUSTRY:
The two general types of protection encountered in industry are thermalprotection and
flow protection.
For liquid-packed vessels, thermal relief valves are generally characterized by the relatively
small size of the valve necessary to provide protection from excess pressure caused by
thermal expansion. In this case a small valve is adequate because most liquids are nearly
incompressible, and so a relatively small amount of fluid discharged through the relief valve
will produce a substantial reduction in pressure.
Flow protection is characterized by safety valves that are considerably larger than those
mounted for thermal protection. They are generally sized for use in situations where
significant quantities of gas or high volumes of liquid must be quickly discharged in
order to protect the integrity of the vessel or pipeline. This protection can alternatively
be achieved by installing a high integrity pressure protectionsystem (HIPPS).
APPLICATION:
Vacuum safety valves (or combined pressure/vacuum safety valves)are used to
prevent a tank from collapsing while it is being emptied, or when cold rinse water is
used after hot CIP (clean-in-place) or SIP (sterilization-in-place) procedures.
Safety valves also evolved to protect equipment such as pressurevessels (firedor
not) andheat exchangers.
The term safety valve should be limited to compressible fluidapplications
(gas, vapor, or steam).
34. ~ 34 ~
Many fire engineshave such relief valves to prevent the over pressurization
of fire hoses.
Valve Type Application Other information
Ball Flow is on or off Easy to clean
Butterfly Good flow control at high capacities Economical
Globe Good flow control Difficult to clean
Plug Extreme on/off situations More rugged, costly than ball valve
35. ~ 35 ~
FINDINGS
For any academic discipline, especially practical streams like engineering field knowledge
should go hand in hand with theoretical knowledge. In university classes our quest for
knowledge is satisfied theoretically. Exposure to real field knowledge is obtained during such
vocational training. We have learnt a lot about pumps, safety valves, flow control valves,
compressors, machine vibrations and their analysis and many more things of working in an
industry. We might have thoroughly learnt the theory behind these but practical knowledge
about these were mostly limited to samples at laboratory. At IOCL we actually saw the
equipments used in industry. Though the underlying principle remains same but there are
differences as far as practical designs are considered.
We also got to know additionally about other features not taught or known earlier. This has
helped to clarify our theoretical knowledge a lot. Apart from knowing about matters restricted
to our own discipline we also got to know some other things about the processing of crude
and manufacturing of various petrochemical products and fuels which we might not have
necessarily read within our curriculum. Such vocational trainings, apart from boosting our
knowledge give us some practical insight into corporate sector and a feeling about the
industry environment. The close interactions with guides, many of whom are just some years
seniors to us have also helped us a lot. It is they who, apart from throwing light on
equipments, have also shown the different aspects and constraints of corporate life.
Discussions with them have not only satisfied our enquiries about machines and processes but
also enlightened about many other extracurricular concepts which are also important. Thus
our training in IOCL has been a truly enlightening learning experience.
