A REPORTON

OPERATIONS OF PIPELINESSUMMER INTERNSHIP

Submitted in partial fulfilment of

BACHELOR OF TECHNOLOGYin

MECHANICAL ENGINEERING (2nd YEAR)

SUBMITTED BY

Priya Kumari

SUBMITTED TO

Sri Arindam BagchiSOM, ERPL, IOCL, KOLKATA

DURATION - 1st MAY, 2015 TO 1st JUNE, 2015

DEPARTMENT OF MECHANICAL ENGINEERING

KIIT UNIVERSITY

TABLE OF CONTENTS

Serial number

TOPIC Page number

1 A brief history of the corporation 5

2 General introduction to IOCL 6

3 Introduction to pipelines 7

4 Roles and function of pipelines 8

5 Basic pipelines operation 8

6 Pipelines hydraulics Slack line flow Surge

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7 Product line pipeline Critical parameter of product Interface

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Serial number TOPIC Page number

2

8 Crude oil pipeline SPM

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9 Pigging 21

10 Valve 26

11 Interface management

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ACKNOWLEDGEMENT

I would like to express my sincere gratitude to Mr. Lalit Kumar Pothal Associate dean, Training and Placement, School of Mechanical Engineering, KIIT University.

I am grateful to our guide Sri A. Bagchi SOM,ERPL,IOCL for the help provided in the completion of the project, which was assigned to me. Without their friendly help and guidance it was difficult to complete the assigned task.

I am also thankful to all the faculty member of school of Mechanical Engineering, for their true help, inspiration.

Last but not the least, I pay my sincere thanks and gratitude to all those who were associated with me during the training period for their support and for making our training valuable and fruitful.

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TOPIC- OPERATIONS OF PETROLEUM PIPELINE

A BRIEF HISTORY OF THE CORPORATION

The story of the petroleum industry in India can be traced to the world's oldest running refinery, at Digboi, which had a modest refining capacity at 25000 tonnes per annum. prior to this, kerosene was imported into the country since the 1860s, mainly for purpose of illumination. In the pre- independence Indian economy, the public sector had a minimal presence. Thus as the growing demand for petroleum products outmatched the capacity of Digboi, the shortfall was met through imports by foreign companies operating in India. these included Burmah oil company, Stanvac, Burmah shell, Caltex and Indo-Burma petroleum company. On the eve of independence, the oil industry was entirely in the hands of these multinationals.

The foundations of an indigenous petroleum industry were laid in the 1950s and '60s. Having formed the oil & naturals gas commission in 1956 for undertaking upstream activities of oil exploration & production, Keshav Dev Malaviya, widely respected as the father of the oil industry in India, focussed his attention on the downstream refining and marketing sector. And from here began the journey of Indian oil.

Indian refineries was established in august 1958 as a wholly government-owned company to set up and operate petroleum refineries and pipelines.

Indian Oil company Ltd, another wholly government enterprise, was formed on 30 June, 1959, and was entrusted with the task of supplying petroleum products to government organisation all over the country by establishing adequate storage and distribution facilities, and undertaking imports, as required. The company was to market product of the two refineries being set up at Guwahati and Barauni.

On September 1, 1964, Indian refineries Ltd. was dissolved and merged with Indian Oil company Ltd. to form a vertically integrated entity, Indian Oil corporation Ltd, straddling both refining and marketing functions. While announcing the historic merger, prof Humayun Kabir, minister of petroleum and chemicals, hoped that Indian Oil would soon handle at least half of the trade in petroleum products. His hopes materialised within just five years.

1 September is celebrated as IndianOil day every year.

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GENERAL INTRODUCTION TO IOCL

IndianOil together with its subsidiaries, accounts for approximately 48 percent of India's petroleum product market, 34 per cent of downstream sector pipelines throughput capacity.

The IndianOil group owns and operates 10 of India's 20 refineries, with a combined capacity of 60.2 million tonnes per annum, or 1.2 million barrels per day. its 10000- km network of cross country crude oil and product pipelines is the most extensive in the country. In 2008-2009, the company sold over 62 million tonnes of petroleum products in the domestic market and exported 3.6 million tonnes.

IndianOil is investing 43, 400 crore through 2007-12 towards refining and pipelines ₹capacity augmentation, marketing infrastructure expansion, product quality up gradation, as well as in integration and diversification initiatives.

Indian Oil Corporation Limited has four divisions which are:

Refinery Marketing R&D Pipelines

REFINERY DIVISIONRefinery Division of IOCL deals with refining of crude oil to finished petroleum products.

MARKETING DIVISIONMarketing division of IOCL deals with supplying the finished petroleum products to consumers.

RESEARCH AND DEVELOPMENT DIVISIONR&D division of IOCL helps in developing new technologies for faster and better working of the corporation.

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PIPELINES DIVISION

INTRODUCTION TO PIPELINES

The term pipeline in broader sense means a facility used to transport commodities from point of receipt to the point of delivery.

Development of pipelines in India:

Most of the earlier refineries in India were installed at costal locations, thus depending on the costal movement of crude oil.

The first crude oil pipeline was laid from Digboi fields to Digboi refinery

During 1960-63, Oil India limited laid the first trunk crude oil pipeline, 1156 KM long from Harkatiya and Moran oil fields to the refineries at Guwahati and Barauni.

The first cross country product pipeline was laid during 1962-64 to transport products from Guwahati refinery to Siliguri.

Subsequently, a number of product and crude oil pipelines were laid in the 60’s, 70’s and 80’s.

The pipelines laid during the 60’s were designed, engineered and constructed by foreign companies. However, the exposure to this technology enabled Indian engineers to gain confidence, and the pipelines which came up later, were designed and constructed with indigenous expertise.

The country today has about 8617 km of major crude oil and product pipelines.

WHY PIPELINES ARE USED AS A MEANS TO TRANSPORT OIL

Lower cost of transportation Lower transit losses Lower energy intensiveness Economies of scale Safety and reliability Environment friendliness Multiproduct handling Decongestion of surface transport system

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ROLES AND FUNCTION OF PIPELINES DIVISION

1. ROLES

Transportation of crude oil to the refineries Transportation of finished petroleum products from refineries / port(s) to bulk

terminals of Indian Oil (Marketing), for onward distribution to consumption centres/points.

Transportation of gas

2. FUNCTION

Conceptualisation of new projects Preparation of feasibility and detailed feasibility reports Execution of projects Operation and maintenance of pipelines and allied systems Consultancy & construction management

BASIC PIPELINE OPERATION:

Run Time System:

Motors or engines are used as prime movers.

Motors: It requires electrical input. It is more efficient. The speed of the motor can be changed by varying frequency. It requires less maintenance. It is environment friendly. It can't be installed everywhere because it needs a constant supply of electricity

Engines: It is a Diesel driven system. It can also be driven by crude oil but it requires a centrifuge to clean out the contaminants. It requires more maintenance.

Manifold: It is the first component of the run time system. It can have supplies from Marketing, Refinery or direct coastal input. Inputs to manifold can be single line from each input point or product wise multiple input.

Booster pumps: Their main function is to provide adequate suction to the mainline pumps. This minimum pressure required by the mainline pumps is defined by a term known as Net Positive Suction Head (NPSH). It is the difference between stagnation head at inlet of pump and vapour pressure head. Boosters are generally installed in parallel.

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Separator filter: It removes the water from the crude/product.

Strainer: It acts as a filter. It filters out all the suspended particulate matter or contaminant.

Turbine Meter /Flow meter: It measures the flow rate of the crude/product in the run time system.

Density meter : It measures the online density of the product or crude oil.

Main line pump: Main line pumps are provided to increase the pressure head to counter the loss in pressure head in pipeline. These are installed in series.

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PIPELINE HYDRAULICS:

HYDRAULICS:

Study of liquids at rest and in motion, specially under pressure, and application of that knowledge in design and control of machines.

PIPELINE SYSTEM :

The system consists of storage facility, hydraulic machines, line pipes, valves, other accessories. The system is constructed to deliver fluid at higher level or to create a pressurized system.

TYPES OF FLOW:

Flow in pipes is of two types, laminar, turbulent.

Laminar flow smooth streamlines highly ordered motion short in length normally appeared in high viscosity flow and small pipe/passage i.e. oil in

small pipe

Turbulent flow rough streamlines highly disordered motion most flow in reality is turbulent high momentum, thus high friction

We also use Reynolds's number to distinguish between these two types of flow.

Re= Inertial forces/viscous forces

= Vavg x D/µ

where, µ = kinematic viscosity

D = internal diameter of pipe

Vavg = average pipe velocity

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Re< 2300, laminar flow 2300<= Re<=4000, transient flow Re> 4000, turbulent flow

FUNDAMENTAL PRINCIPLES OF HYDRAULICS :

Conservation of mass For steady, incompressible flow of liquid, mass entering any section of the pipe must be equal to the mass exiting that section. This is also known as continuity equation.

Work energy principleFor steady, one dimensional flow of a liquid per unit weight, the principle states that the total energy of the fluid flow at any point should be conserved.

Hydraulic gradient: a hydraulic gradient is the height that a column of flow will rise to if small tubes are installed along the pipeline.

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Momentum equation

For steady incompressible, one dimensional flow through a pipe, the momentum equation along the direction of pipe can be stated as the net change of momentum in flow direction is always proportional to the net unbalanced flow in the same direction.

Fnet=ρgQ (V2-V1)

TYPES OF LOSSES IN CLOSED FLOW SYSYTEM:

Losses are mainly due to friction and obstruction

There are mainly two types of losses

1. Major loss2. Minor loss

MAJOR LOSS:This is also known as t pressure losses or head losses. It solely depends on the pipe. In a pipeline system the pressure drop is mainly the friction drophf = f(l/d)(v2/2g)f= friction factor, d= diameter, l=length, v=average velocity of flow.This is Darcy-Weisbach equation.

For laminar flow f= 64/ReFrom this equation we can see that the friction factor in laminar flow is independent of roughness.

The head loss represents the additional height that the fluid needs to be raised by a pump to overcome the frictional losses in the pipe.

Friction factor for turbulent flow can be given by Colebrook equation. 1/f0.5 = -2log((3.7D)+(2.51/Re(f)0.5))where, is roughness D is diameter of the pipe.From this equation we can say that the friction factor for turbulent flow depends on roughness.

MINOR LOSSES:Minor losses in flow is due to a presence of various fittings, valves, bends, elbows, tees, inlets, exits and contractions in pipes.

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Components with sharp edges also cause minor losses. It has higher loss coefficient compared to well rounded pipes. Sharp edge introduce recirculation flow as fluid flow will be unable to make sharp 90 deg turn.

PIPELINE SYSTEM DESIGN:

Major inputs:

Length (distance), elevation

Steps involved:

Selection of probable sizes Hydraulics, system configuration, capital and operating costs, present value for all

sizes. Selection - size with least present value

LOCATION FOR PUMP STATIONS:

The intersection of hydraulic gradient with the elevation profile gives the theoretical location of each pump station. Actual location must be moved upstream from theoretical locations to provide positive suction head.

Other considerations are MAOP, land restriction etc.

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FLOW THROUGH PIPELINES:

SDH/MAOP

Q

DISTANCE 0 L

ELEVATION H’ H”

RESIDUAL HEAD - h

ENERGY EQUATION : For Flow as Q cu m/hr (MMTPA)

STATION DISCHARGE HEAD (MCL) = f X L + (H” - H’ ) + h

where, f = FRICTION LOSS : L = DISTANCE

H”-H’ = ELEVATION DIFFERENCE; h = RESIDUAL HEAD

Maximum allowable operating pressure:

MAOP = (Sx2TxS.F)/D

Where, S=yield stress, T=wall thickness, D=outer diameter of the pipe, S.F.=safety factor.

Depending upon the value of SDH/MAOP number of stations are determined .

CASE 1: SDH<=MAOP ;no pump stations required.

CASE 2:SDH>MAOP & <2MAOP;one pump station is required.

CASE 3: SDH>2MAOP & <3MAOP; two pump stations are required.

SLACK LINE FLOW:

It occurs under certain topographic conditions. A drastic elevation changes coupled with insufficient back pressure in the downstream section of pipeline. This causes the pressure in the pipeline to fall below the vapor pressure of the liquid resulting in creation of vapor bubbles in the pipelines.

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Effects of slack line flow:

More interface generation in pipeline. Collapse of vapor bubble may cause pressure surge. Frictional head loss is much greater than tight line regions. It affects the hydraulics of the pipelines.

Prevention of slack:

Ensure sufficient back pressure at downstream station. so that the positive pressure is maintained throughout the pipeline.

Pressure in the pipeline should be always more than the vapor pressure of the liquid under transportation.

A minimum pressure of 1-2 kg/cm2 shall be ensured at peak points always.

SURGE: Surge pressure takes place whenever there is a sudden change in flow velocity. In pipeline, surge takes place due to valve closure, pump trip, Emergency Shut Down

(ESD) etc The surge pressure can exceed the design pressure of pipe, leading to catastrophic

failure In order to protect the pipeline from high surge pressure, Surge relief system is

adopted.

Ways to prevent surge:

Eliminate sudden change in velocity

Use variable speed to have slow start/stop Use PCV/FCV to change flow/pressure slowly Reduced start/stop – at full rpm Avoid Sudden stop/ESD (emergency shutdown)

PIPELINES IS SUBCATEGORIZED INTO:

Crude oil pipeline Product pipeline

PRODUCT PIPELINES OPERATIONS:

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Multi Product Pipelines - Transport two or more different products in the same pipeline Sequence is determined in line with compatibility. No physical separation between the different products. Product pipeline operation is similar to crude oil pipeline operation Interface management is an aspect of Multiproduct Pipelines operation that is

different from crude oil pipeline

PRODUCTS PUMPED

HSD MS SKO / PCK / LS-SKO / “0” SKO ATF MTO LDO SRN MRN INTERMEDIATE NAPTHA /INDMAX GASOLENE

PRODUCT SEQUENCING:

HSD SKO MS SRM SKO ATF SKO

CRITICAL PARAMETERS OF PRODUCTS

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HSD – SULPHUR/CETANE NO./POUR POINT

MS – SULPHUR/RON/FBP

SKO / PCK / LS-SKO / “0” SKO – SULPHUR/FLASH POINT/SMOKE POINT

ATF – FBP/SILVER STRIP CORROSION

MTO – FLASH POINT/FBP

LDO – FLASH POINT/POUR POINT

SRN – FBP/AROMATICS/COLOUR

MRN – FBP/AR

DESCRIPTION OF CRITICAL PARAMETERS :

SULPHURIn case of SKO, < or = 50 ppm – PCK< or = 1000 ppm – Low Sulphur1000 to 2500 ppm – Normal SKO< or = 50 ppm – E4 MS/HSD150 ppm max. – E3MS350 ppm max. – E3HSDIn case of crude oil, < or = 0.5% by wt. – Low Sulphur (Sweet) Crude Oil >0.5% by wt. – High Sulphur (Sour) Crude Oil

CETANE NUMBERThe Cetane Number refers to the combustion quality of diesel fuel. It represents the time delay between the start of injection process and the point where the fuel ignites. It denotes the percentage (by volume) of cetane (chemical name Hexadecane) in a combustible mixture ofdiesel fuel being tested. Cetane number of HSD is 51.

RESEARCH OCTANE NUMBER (RON)It determines petrol's 'anti-knock' quality or resistance to pre-ignition.

POUR POINTThe pour point of a liquid is the temperature at which it becomes semi solid and loses its flow characteristics.

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In crude oil a high pour point is generally associated with high paraffin content.

FLASH POINTThe flash point of a volatile material is the lowest temperature at which it can vaporize to form an ignitable mixture in air.

SMOKE POINTThe maximum flame height in millimetres (mm) at which the oil burns without smoking when tested in a standard wick-fed lamp under specified conditions is termed and smoke point.

COPPER STRIP CORROSIONIs checked to evaluate the degree to which a lubricant will corrode copper-containing materials.

API GravityDensity of crude is classified by the American Petroleum Institute (‘API’). API gravity is defined based on density at temperature of 15.6 0C or 60 0F. The higher the API gravity, the lighter the crude.

BASIC SEDIMENT & WATER (BS&W)It is a technical specification of certain impurities in crude oil. When extracted from an oil reservoir, the crude oil will contain some amount of water and suspended solids from the reservoir formation.

TOTAL ACID NUMBER (TAN)The total acid number (TAN) is a measurement of acidity that is determined by the amount of potassium hydroxide in milligrams that is needed to neutralize the acids in one gram of oil.

INTERFACE:

What is an interface?

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Interface is a mixed volume of product created between two different and adjacent products as they flow through the pipeline system.

Interface is a feature of all multi product pipeline systems.

A critical interface is the mixture generated between two significantly different products. One of which can seriously affect the properties of others.

Interface generation is dependent on the factors like Pipeline diameter, velocity of the flow, topography of the land, turbulent flow conditions and the type of products.

CRUDE OIL PIPELINE OPERATION:

TYPES OF CRUDE:

low sulphur crude high sulphur crude

ACTIVITIES:

1. OFF SHORE OPERATIONAs the oil production in India is very low and doesn't meet the demands of Indian population. Hence corporations such as IOCL hugely depend on the supply of crude from other countries. This large amount of crude is carried by ULCC and VLCC. Off shore operations include the transfer of crude oil from VLCC /ULCC to crude oil terminal through SPM.

SPM (SINGLE POINT MOORING SYSTEM):

It is a loading buoy anchored offshore, that serves as a mooring point and interconnects for tankers loading or offloading gas or liquid products.

They are capable of handling any size ship, even very large crude carriers (VLCC) where no alternative facility is available.

ADVANTAGES OF SPM:

SPM systems are regarded as instant port since they can be installed in deeper areas without any need for construction of jetties.

SPM systems facilitate faster turnaround of vessels. When production facilities are into deep sea, SPM is best way for cargo transfers via

vessel.

SALIENT FEATURES OF SPM All SPMs have a floating buoy anchored to seabed through anchor chains secured on

piles.

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This buoy has a floating hose system for cargo transport, comprising of floating hoses and sub-sea hoses.

The floating hoses connect between the buoy and the tanker whereas the sub-sea hoses connect between buoy and the sub-sea pipeline.

PARTS OF SPM:

There are 4 parts in the total buoying system of a SPM –1. The body of the buoy2. Mooring and anchoring elements3. Product transfer system4. Other components

THE BODY OF THE BUOY: The buoy body usually is supported on static legs attached to the seabed, with a rotating

part above water level connected to the (off) loading tanker. The two sections are linked by a roller bearing, referred to as the "main bearing". The moored tanker can freely weathervane around the buoy and find a stable position

due to this arrangement.

MOORING AND ANCHORING PARTS:

Moorings fix the buoy to the seabed. Buoy design must account for the behaviour of the buoy given applicable wind, wave

and current conditions and tanker sizes. This determines the optimum mooring arrangement and size of the various mooring leg

components. Anchoring points are greatly dependent on local soil condition.

A tanker is moored to a buoy by means of a hawser arrangement. The hawser arrangement usually consists of nylon rope, which is shackled to an integrated mooring uni-joint on the buoy deck.

PRODUCT TRANSFER SYSTEM: The heart of each buoy is the product transfer system. This system transfers products to the off take tanker from a geostatic location e.g.

a pipeline end manifold (PLEM) located on the seabed.OTHER COMPONENTS:

A boat landing, providing access to the buoy deck Fender to protect the buoy Lifting and handling equipment to aid materials handling

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Navigational aids for maritime visibility, and fog horn to keep moving vessel alert An electrical subsystem to enable valve operation and to power navigation aids or

other equipment.

PIGGING:

PIG – Pipeline Inspection Gauge PIGGING - It is the practice of using Pipeline Inspection Gauge (PIG) to perform

various maintenance operations on a pipeline without stopping the flow of product in the pipeline.OR

A process of pushing a device (PIG) equipped with metal wire brushes to clean the deposits on the inner walls of the pipeline.

PURPOSE OF PIGGING:

To clean the new pipe debris. To know the inside pipe diameter profile. For inspection and measurement of any corrosion or metal loss. If the pipeline contains butterfly valves, or reduced port ball valves, the pipeline cannot

be pigged. Full port (or full bore) ball valves cause no problems because the inside diameter of the ball is the same as that of the pipe.

TYPES OF PIG –

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1. CLEANING OR SCRAPPER PIG

A utility pig that uses cups, scrapers, or brushes, to remove dirt, rust, mill scale, or other foreign matter from the pipeline.

Cleaning pigs are run to increase the operating efficiency of a pipeline or to facilitate inspection of the pipeline.

2. FOAM PIG

Used for cleaning, de-watering and swabbing

Can be coated with urethane for more durability 

Can be customized to accommodate an assortment of situations

3. BATCHING PIG

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A utility pig that forms a moving seal in a pipeline to separate liquid from gas media, or to separate two different products being transported in the pipeline.

The most-common configurations of batching pigs are cup pigs and sphere pigs.

4. GAUGE PIG

Simplest geometry tool used to detect dents, deformations and tight bends

gauging plates are available in aluminium or steel, manufactured to any thickness or diameter.

5. SEALING OR BI-DI PIG

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Follows another pig providing sealing from behind

Normally sized between 103% and 108 % of the pipe internal diameter

6. IN LINE INSPECTION TOOLS (ILI) / SMART PIGS

Smart Pigs provides information on the condition of the pipe and/or its contents

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The following information are provided –

Diameter / geometry measurements Curvature monitoring Pipeline profile Temperature / pressure recording; Bend measurement; Metal-loss / corrosion detection Photographic inspection; Crack detection; Wax deposition measurement; Leak detection; Product sampling, and; Mapping.

VALVES

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A device that regulates the flow of gases, liquids or loose materials through an aperture, such as a pipe, by opening, closing or obstructing a port or passageway.

Valves isolate, switch, and control fluid flow in piping systems.

Can be operated manually (using levers or gear operators) or remotely (using electric, pneumatic, electro-pneumatic, and electro-hydraulic powered actuators).

Manual valves are usually used only if they will be operated infrequently or no power source is available.

TYPES OF VALVE

BASIC TYPES –

Isolation valves: On/Off valves –

Typically operated in fully open or fully closed condition.

Designed to have a tight reliable seal during shut-off and minimal flow restriction when open

Switching valves: Converge or divert flow in a piping system

Control valves: Used to modulate flow (i.e., vary flow by opening or closing by a certain percentage)

1. Isolation valve

a) Ball valve

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A ball is provided with a hole that can be rotated to align with the flow or block it

They provide quick, tight shutoff and require only a ¼ turn to operate

Can be actuated with pneumatic and electric actuators

b) Plug valve

Similar to a ball valve except that a cylinder is used instead of a sphere.

More expensive but more rugged than a ball valve.

Requires more torque to turn but still easy to actuate.

c) Butterfly valve

Can be used for both general and severe applications

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Liners help to provide tight shutoff

The most economical valves per comparable capacity and easily actuated with pneumatic and electric actuators

d) Gate valve

A sliding disk slides up and down in and out of the fluid

Good for high pressure drop and high temperature applications where operation is not frequent

Manual operation or else multi-turn electric actuators are most common

e) Globe valve

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A conical plug moves in and out of the fluid and they can be used for shutoff as well as throttling. Used in high pressure drop and temperature applications.

Manual operation or else multi-turn electric actuators are most common.

Easier to repair but more pressure drop than a gate or plug valve.

2. Switching valve

Converge and divert flow in a piping system

Usually 3-way valves used because they can take the place of 2 2-way valves

3-way valves are usually ball, plug, or globe design

2 butterfly valves mounted on a pipe tee will also work and is cost-effective for large pipes

3. Control valve

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They are used to modulate flow.

Pressure control valves (PCVs) are used to separate high pressure piping from low pressure station piping.

They are generally globe valves.

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INTERFACE MANGEMENT:

Interface is a mixed volume of product created between two different and adjacent products as they flow through the pipeline system.

Interface is a feature of all multi product pipeline systems.

A critical interface is the mixture generated between two significantly different products. One of which can seriously affect the properties of others.

Interface generation is dependent on the factors like Pipeline diameter, velocity of the flow, topography of the land, turbulent flow conditions and the type of products .

Allowable Intermix of Interface:

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INTERFACE MONITORING:

It is the responsibility of dispatcher to calculate arrival of interface at a particular station and intimate the operating personnel well in advance to track the interface.

Both IFD (I/F detector) and Manual tracking should be resorted for tracking of interface.

IFD as well as the settings are to be checked for its working every fortnight and duly recorded.

“Batch Reset Counter” wherever installed should be used to indicate the batch length of each batch in addition to using the counter for tank receipts.

PRECAUTIONS

Maintaining constant line pressure. Maintaining Constant rate of flow. Avoid frequent shut downs. During planned shutdown, pipeline should be pressurized slowly and gradually to the

required level. Considering hydraulic gradients while optimizing operational parameters. Application of standard measuring instruments such as thermometer, hydrometer and

sampling jars etc. Constant vigil during Interface tracking.

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