Indian Oil Corporation Limited Panipat Refinery & Petrochemical Complex

July 5

2013Submitted By:

Pawan Kumar

B.Tech.

Instrumentation & Control Engineering

National Institute of Technology, Jalandhar

Vocational Training at IOCL (June 10, 2013 to July 5, 2013 )

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AcknowledgementI would like to thank Mr. J S Sahota, Chief Manager (Training & Development) for giving me an opportunity to explore my ideas and interact with experts of the industry at Panipat Refinery.

I would also thank to Mr. Y B Joshi, DM (Training & Development) , Mr. N. Vinod, Chief Manager (Inst.) and Mr. S. Thakkar, Sr. Manager (Inst.) for their valuable suggestions during the training period.

I extend my heartiest thanks to Mr. Kaushik Dutta, Dy. Manager (Inst.) and Mr. S K Verma, Sr. Inst. Engineer (MEG Unit) for their inspiration and kind support. This training would have not been so fruitful without their guidance.

I would also like to thank all officers and staff of the company for their support and cooperation.

Finally I would like to express my sincere gratitude to my parents, for helping me to undertake this training and constantly encouraging me to interact with the experts and make the best use of the immense opportunities available at the refinery.

PAWAN KUMAR

NIT Jalandhar

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ContentsS. No. Topics Page No.1. An Overview

IOCL Panipat Refinery Panipat Naphtha Cracker

3356

2. Field Instruments Pressure Measurement Temperature Measurement Flow Measurement Level Measurement Valves

7710141921

3. Process Control & Monitoring Distributed Control System Programmable Logic Controller Bently Nevada (Vibration Analysis) Plant Resource Manager (PRM)

2727303032

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1. AN OVERVIEW: Indian Oil Corporation Ltd.:

Indian Oil Corporation Limited, or IndianOil, is an Indian state-owned oil and gas corporation with its headquarters in New Delhi, India. The company is the world's 83rd largest public corporation, according to the Fortune Global 500 list, and the largest public corporation in India when ranked by revenue. IndianOil and its subsidiaries account for a 49% share in the petroleum products market, 31% share in refining capacity and 67% downstream sector pipelines capacity in India. The IndianOil Group of Companies owns and operates 10 of India's 22 refineries with a combined refining capacity of 65.7 million metric tonnes per year. The President of India owns 78.92% (1.9162 billion shares) in the company. In FY 2012 IOCL sold 75.66 million tonnes of petroleum products and reported a PBT of 37.54 billion, and the Government of India earned an excise duty of 232.53 billion and tax of 10.68 billion. It is one of the seven Maharatna status companies of India, apart from Coal India Limited, NTPC Limited, Oil and Natural Gas Corporation, Steel Authority of India Limited, Bharat Heavy Electricals Limited and Gas Authority of India Limited.

IndianOil operates the largest and the widest network of fuel stations in the country, numbering about 20,575 (16,350 regular ROs & 4,225 Kisan Seva Kendra). It has also started Auto LPG Dispensing Stations (ALDS). It supplies Indane cooking gas to over 66.8 million households through a network of 5,934 Indane distributors. In addition, IndianOil's Research and Development Center (R&D) at Faridabad supports, develops and provides the necessary technology solutions to the operating divisions of the corporation and its customers within the country and abroad.

Indian Oil began operations in 1959 as Indian Oil Company Ltd. The Indian Oil Corporation was formed in 1964, with the merger of Indian Refineries Ltd. Indian Oil is the biggest oil producer and marketer Oil's product range covers petrol, diesel, LPG, auto LPG, aviation turbine fuel, lubricants, naphtha, bitumen, paraffin, kerosene etc. Xtra Premium petrol, Xtra Mile diesel, Servo lubricants, Indane LPG cooking gas, Autogas LPG, IndianOil Aviation are some of its prominent brands.

Recently Indian Oil has also introduced a new business line of supplying LNG (liquefied natural gas) by cryogenic transportation. This is called "LNG at Doorstep".

It is also the 18th largest petroleum company in the world and the No. 1 petroleum trading company among the national oil companies in the Asia-Pacific region. IOCL was featured on the 2011 Forbes Global 2000 at position 243. It is the fifth most valued brand in India according to an annual survey conducted by Brand Finance and The Economic Times in 2010.

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Refineries

Digboi Refinery, in Assam, is India's oldest refinery and was commissioned in 1901. Originally a part of Assam Oil Company, it became part of IndianOil in 1981. Its original refining capacity had been 0.5 MMTPA since 1901. Modernization project of this refinery was completed by 1996 and the refinery now has an enhanced capacity of 0.65 MMTPA.

Guwahati Refinery, the 1st public sector refinery of the country, started on 1 January 1962. Its capacity is 1 MMTPA.

Bongaigaon Refinery became the 8th refinery of IndianOil after merger of Bongaigaon Refinery & Petrochemicals Limited w.e.f. 25 March 2009.

Barauni Refinery, in Bihar. It was commissioned in 1964 with a capacity of 1 MMTPA. Its capacity today is 6 MMTPA.

Gujarat Refinery, at Koyali (near Vadodara) in Gujarat in Western India, is IndianOil’s 2nd largest refinery. The refinery was commissioned in 1965. It also houses the 1st hydrocracking unit of the country. Its present capacity is 13.70 MMTPA.

Haldia Refinery is the only coastal refinery of the Corporation. It was commissioned in 1975 with a capacity of 2.5 MMTPA, which has since been increased to 7.5 MMTPA

Mathura Refinery was commissioned in 1982 as the 6th refinery in the fold of IndianOil and with an original capacity of 6.0 MMTPA. The capacity of Mathura refinery was increased to 8.8 MMTPA.

Panipat Refinery is the 7th and largest refinery of IndianOil. The original refinery with 6 MMTPA capacity was built and commissioned in 1998. Panipat Refinery has since expanded its refining capacity to 15 MMTPA.

Paradip Refinery- The commissioning of 15 million tonnes per annum refinery in November 2012 has been delayed and is now expected to be operational only in September 2013.

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Panipat Refinery:

It was set up in 1998. Panipat Refinery is the 7th refinery belonging to Indian Oil Corporation Limited. It is one of South East Asia’s largest integrated petrochemicals plants. Panipat Refinery meets the demand of petroleum products of Haryana and of the entire North-West Region including Punjab, J&K, Himachal, Chandigarh, Uttaranchal state and part of Rajasthan & Delhi. It stands by Indian Oil vision to become a major, diversified, transnational, integrated energy company, with national leadership and a strong environment conscience, playing national role in oil security and public distribution. Being younger of the Indian Oil refineries it houses latest refining technologies from Axens; France, Haldor-Topsoe; Denmark, UOP; USA, Stone & Webster; USA and Delta Hudson-Canada, Dupont, USA and ABB Luumas. The original cost of the refinery's construction was Rs 3868 crores. It commenced with a capacity of 6 MMTPA and has been recently augmented to 12 MMTPA at a cost of Rs 4165 Crores. The refinery is designed to handle both indigenous and imported crudes. It receives crude through the Salaya Mathura Pipeline which also supplies crude to Mathura and Baroda refineries.

In addition to crude and vacuum distillation units, the major refining units are catalytic reforming unit, once-through Hydrocracker unit, Resid Fluidised Catalytic Cracking unit, visbreaker unit, delayed coking unit, bitumen blowing unit, hydrogen generation unit, sulphur block and associated auxiliary facilities. In order to produce low sulphur diesel, a Diesel Hydro Desulphurisation Unit (DHDS) was commissioned in 1999.

The refinery also houses PX-PTA units which were commissioned in June 2006. They produce paraxylene and PTA. PTA is a useful raw material for producing other commercial polymers. It produces Benzene as one of the by products.

Expanding its presence in petrochemical space, Indian Oil has commissioned a Naphtha Cracker Complex adjacent to Panipat refinery complex at a project cost of Rs 14439 Crores.[3] It produces Ethylene and propylene which are further used to produce polymers like Poly propylene, Low/High density polyethylene and mono ethylene glycol.

Panipat Refinery has been further augmented with an additional capacity of 3 MMTPA taking the total capacity to 15 MMTPA. With Euro III/IV norms in place, Panipat Refinery is a large contributor of Ultra Low sulphur Diesel for Indian Oil.

Highlights

The refinery's highlights include:

Zero discharge of effluent gases. The presence of four ambient air monitoring stations that were in place well before

the refinery was in use. It is an eco-friendly refinery, as indicated by a green belt outside it.

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The establishment of a totally electronic-based communication system within the refinery.

It has the lowest manpower of all refineries in the region with similar capacities.

Naphtha Cracker Plant, Panipat:  

The world-class Naphtha Cracker at Panipat, built at a cost of Rs 14,400 crore, is the largest operating cracker capacity in India.

The feed for the unit is sourced internally from IndianOil's Koyali, Panipat and Mathura refineries. The Naphtha Cracker comprises of the following downstream units - Polypropylene (capacity: 600,000 tonnes), High Density Polyethylene (HDPE) (dedicated capacity: 300,000 tonnes) and Linear Low Density Poly Ethylene (LLDPE) (350,000 tonnes Swing unit with HDPE), Mono Ethylene Glycol (MEG) plant (capacity: 325,000 tonnes).

The cracker will produce over 800,000 tonnes per annum of ethylene, 600,000 tonnes per annum of Propylene, 125,000 tonnes per annum of Benzene, and other products viz., LPG, Pyrolysis Fuel Oil, components of Gasoline and Diesel.

The Polypropylene (PP) unit is designed to produce high quality and high value niche grades including high speed Bi-axially Oriented Polypropylene (BOPP) (used for food packaging and laminations), high clarity random co-polymers (used for food containers and thin walled products) and super impact co-polymer grades (used for batteries, automobile parts, luggage and heavy duty transport containers). Polyethylene is used for making injection moulded caps, heavy duty crates, containers, bins, textile bobbins, luggage ware, thermoware, storage bins, pressure pipes (for gas and water), small blow-moulded bottles, jerry cans, etc.

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2. Field Instruments

Pressure Measurement:

Many techniques have been developed for the measurement of pressure and vacuum. Instruments used to measure pressure are called pressure gauges or vacuum gauges.

Differential pressures are commonly used in industrial process systems. Differential pressure gauges have two inlet ports, each connected to one of the volumes whose pressure is to be monitored. In effect, such a gauge performs the mathematical operation of subtraction through mechanical means, obviating the need for an operator or control system to watch two separate gauges and determine the difference in readings.

Bourdon:

The Bourdon pressure gauge uses the principle that a flattened tube tends to straighten or regain its circular form in cross-section when pressurized. Although this change in cross-section may be hardly noticeable, and thus involving moderate stresses within the elastic range of easily workable materials, the strain of the material of the tube is magnified by forming the tube into a C shape or even a helix, such that the entire tube tends to straighten out or uncoil, elastically, as it is pressurized.

C-type Bourdan

Diaphragm:

A second type of aneroid gauge uses the deflection of a flexible membrane that separates regions of different pressure. The amount of deflection is repeatable for known pressures so the pressure can be determined by using calibration. The deformation of a thin diaphragm is dependent on the difference in pressure between its two faces. The reference face can be open to atmosphere to measure gauge pressure, open to a second port to measure

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differential pressure, or can be sealed against a vacuum or other fixed reference pressure to measure absolute pressure. The deformation can be measured using mechanical, optical or capacitive techniques. Ceramic and metallic diaphragms are used.

Useful range: above 10-2 Torr (roughly 1 Pa).

Diaphragm

Barometer:

A mercury barometer has a glass tube with a height of at least 84 cm, closed at one end, with an open mercury-filled reservoir at the base. The weight of the mercury creates a vacuum in the top of the tube. Mercury in the tube adjusts until the weight of the mercury column balances the atmospheric force exerted on the reservoir. High atmospheric pressure places more force on the reservoir, forcing mercury higher in the column. Low pressure allows the mercury to drop to a lower level in the column by lowering the force placed on the reservoir. Since higher temperature at the instrument will reduce the density of the mercury, the scale for reading the height of the mercury is adjusted to compensate for this effect.

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Manometer:

A manometer could also refer to a pressure measuring instrument, usually limited to measuring pressures near to atmospheric. The term manometer is often used to refer specifically to liquid column hydrostatic instruments.

This is the most simple and precise device used for the measurement of pressure. It consists of a transparent tube constructed in the form of an elongated 'U', and partially filled with the manometeric fluid such as mercury. The purpose of using mercury as the manometeric fluid is that their specific gravity at various temperatures are known exactly and they don’t stick to the tube.

Capacitive:

Uses a diaphragm and pressure cavity to create a variable capacitor to detect strain due to applied pressure. Common technologies use metal, ceramic, and silicon diaphragms. Generally, these technologies are most applied to low pressures.

Electromagnetic:

Measures the displacement of a diaphragm by means of changes in inductance (reluctance), LVDT, Hall Effect, or by eddy current principle.

Piezoelectric:

Uses the piezoelectric effect in certain materials such as quartz to measure the strain upon the sensing mechanism due to pressure. This technology is commonly employed for the measurement of highly dynamic pressures.

Piezoresistive strain gauge:

Uses the piezoresistive effect of bonded or formed strain gauges to detect strain due to applied pressure. Common technology types are Silicon (Monocrystalline), Polysilicon Thin Film, Bonded Metal Foil, Thick Film, and Sputtered Thin Film. Generally, the strain gauges are connected to form a Wheatstone bridge circuit to maximize the output of the sensor and to reduce sensitivity to errors. This is the most commonly employed sensing technology for general purpose pressure measurement. Generally, these technologies are suited to measure absolute, gauge, vacuum, and differential pressures.

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Temperature Measurement:

Many methods have been developed for measuring temperature. Most of these rely on measuring some physical property of a working material that varies with temperature.

Thermocouples: A thermocouple consists of two dissimilar conductors in contact, which will produce a voltage when heated. The size of the voltage is dependent on the difference of temperature of the junction to other parts of the circuit. Any junction of dissimilar metals will produce an electric potential related to temperature.

In contrast to most other methods of temperature measurement, thermocouples are self-powered and require no external form of excitation. The main limitation with thermocouples is accuracy; system errors of less than one degree Celsius (°C) can be difficult to achieve.

When any conductor is subjected to a thermal gradient, it will generate a voltage. This is now known as the thermoelectric effect or See-beck effect. Any attempt to measure this voltage necessarily involves connecting another conductor to the "hot" end. This additional conductor will then also experience the temperature gradient, and develop a voltage of its own which will oppose the original. Fortunately, the magnitude of the effect depends on the metal in use.

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Thermistors:

A thermistor is a type of resistor whose resistance varies significantly with temperature, more so than in standard resistors. The word is a portmanteau of thermal and resistor. Thermistors are widely used as inrush current limiters, temperature sensors, self-resetting overcurrent protectors, and self-regulating heating elements.

Thermistors differ from resistance temperature detectors (RTD) in that the material used in a thermistor is generally a ceramic or polymer, while RTDs use pure metals. The temperature response is also different; RTDs are useful over larger temperature ranges, while thermistors typically achieve a higher precision within a limited temperature range, typically −90 °C to 130 °C.

Resistance Temperature Detector(RTD):

Resistance temperature detectors ('RTD's), are sensors used to measure temperature by correlating the resistance of the RTD element with temperature. The RTD element is made from a pure material, typically platinum, nickel or copper. The material has a predictable change in resistance as the temperature changes; it is this predictable change that is used to determine temperature.

They are slowly replacing the use of thermocouples in many industrial applications below 600 °C, due to higher accuracy and repeatability.

Two-wire configuration :

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The simplest resistance thermometer configuration uses two wires. It is only used when high accuracy is not required, as the resistance of the connecting wires is added to that of the sensor, leading to errors of measurement. This configuration allows use of 100 meters of cable. This applies equally to balanced bridge and fixed bridge system.

Three-wire configuration:

In order to minimize the effects of the lead resistances, a three-wire configuration can be used. Using this method the two leads to the sensor are on adjoining arms. There is a lead resistance in each arm of the bridge so that the resistance is cancelled out, so long as the two lead resistances are accurately the same. This configuration allows up to 600 meters of cable.

RTDs vs thermocouples:

The two most common ways of measuring industrial temperatures are with resistance temperature detectors (RTDs) and thermocouples. Choice between them is usually determined by four factors:-

Temperature: If process temperatures are between -200 to 500 °C (-328 to 932 °F), an industrial RTD is the preferred option. Thermocouples have a range of -180 to 2,320 °C (-292 to 4,208 °F),[15] so for temperatures above 500 °C (932 °F) they are the only contact temperature measurement device.

Response time: If the process requires a very fast response to temperature changes—fractions of a second as opposed to seconds (e.g. 2.5 to 10 s)—then a thermocouple is the best choice. Time response is measured by immersing the sensor in water moving at 1 m/s (3 ft/s) with a 63.2% step change.

Size: A standard RTD sheath is 3.175 to 6.35 mm (0.1250 to 0.250 in) in diameter; sheath diameters for thermocouples can be less than 1.6 mm (0.063 in).

Accuracy and stability requirements: If a tolerance of 2 °C is acceptable and the highest level of repeatability is not required, a thermocouple will serve. RTDs are capable of higher accuracy and can maintain stability for many years, while thermocouples can drift within the first few hours of use.

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Pyrometer:

A pyrometer is a non-contacting device that intercepts and measures thermal radiation, a process known as pyrometry. This device can be used to determine the temperature of an object's surface.

A pyrometer has an optical system and a detector. The optical system focuses the thermal radiation onto the detector. The output signal of the detector (temperature T) is related to the thermal radiation or irradiance j* of the target object through the Stefan–Boltzmann law, the constant of proportionality σ, called the Stefan-Boltzmann constant and the emissivity ε of the object.

This output is used to infer the object's temperature. Thus, there is no need for direct contact between the pyrometer and the object, as there is with thermocouples and resistance temperature detectors (RTDs).

Pyrometers are suited especially to the measurement of moving objects or any surfaces that can’t be reached or can’t be touched.

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Flow Measurement:

Flow measurement is the quantification of bulk fluid movement. Flow can be measured in a variety of ways. Positive-displacement flow meters accumulate a fixed volume of fluid and then count the number of times the volume is filled to measure flow. Other flow measurement methods rely on forces produced by the flowing stream as it overcomes a known constriction, to indirectly calculate flow. Flow may be measured by measuring the velocity of fluid over a known area.

Orifice Plate:

An orifice plate is a device used for measuring flow rate. It uses the principle namely Bernoulli's principle which states that there is a relationship between the pressure of the fluid and the velocity of the fluid. When the velocity increases, the pressure decreases and vice versa.

An orifice plate is a thin plate with a hole in the middle. It is usually placed in a pipe in which fluid flows. When the fluid reaches the orifice plate, the fluid is forced to converge to go through the small hole; the point of maximum convergence actually occurs shortly downstream of the physical orifice, at the so-called vena contracta point (see drawing to the right). As it does so, the velocity and the pressure changes. Beyond the vena contracta, the fluid expands and the velocity and pressure change once again. By measuring the difference in fluid pressure between the normal pipe section and at the vena contracta, the volumetric and mass flow rates can be obtained from Bernoulli's equation.

It is basically a crude form of Venturi meter, but with higher energy losses. There are three type of orifice: concentric, eccentric, and segmental.

Orifice plates are most commonly used for continuous measurement of fluid flow in pipes.

Venturi Meter:

The Venturi meter works on the principle of Venturi effect. The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section of

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pipe. As fluid flows through a venturi, the expansion and compression of the fluids cause the pressure inside the venturi to change.

A Venturi meter constricts the flow in same fashion, and pressure sensors measure the differential pressure before and within the constriction. This method is widely used to measure flow rate in the transmission of gas through pipelines.

Pitot tube:

A pitot tube is a pressure measurement instrument used to measure fluid flow velocity. It is widely used to measure air and gas velocities in industrial applications. The pitot tube is used to measure the local velocity at a given point in the flow stream and not the average velocity in the pipe or conduit.

The basic pitot tube consists of a tube pointing directly into the fluid flow. As this tube contains fluid, a pressure can be measured; the moving fluid is brought to rest (stagnates) as there is no outlet to allow flow to continue. This pressure is the stagnation pressure of the fluid, also known as the total pressure or the pitot pressure. The measured stagnation pressure cannot itself be used to determine the fluid velocity (airspeed in aviation). However, Bernoulli's equation states:

Stagnation pressure = static pressure + dynamic pressure

The above equation applies ONLY to fluids that can be treated as incompressible. Liquids are treated as incompressible under almost all conditions. Gases under certain conditions can be approximated as incompressible. In industry, the velocities being measured are often those flowing in ducts and tubing where measurements by an anemometer would be difficult to obtain. In these kinds of measurements, the most practical instrument to use is the pitot tube.

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Rotameter:

A rotameter is a device that measures the flow rate of liquid or gas in a closed tube.

A rotameter consists of a tapered tube, typically made of glass with a 'float', actually a shaped weight, inside that is pushed up by the drag force of the flow and pulled down by gravity. Drag force for a given fluid and float cross section is a function of flow speed squared only, see drag equation.

A higher volumetric flow rate through a given area increases flow speed and drag force, so the float will be pushed upwards. However, as the inside of the rotameter is cone shaped, the area around the float through which the medium flows increases, the flow speed and drag force decrease until there is mechanical equilibrium with the float's weight.

Floats are made in many different shapes, with spheres and ellipsoids being the most common.

Turbine flow meter:

The turbine flow meter translates the mechanical action of the turbine rotating in the liquid flow around an axis into a user-readable rate of flow. The turbine tends to have all the flow traveling around it. The turbine wheel is set in the path of a fluid stream. The flowing fluid impinges on the turbine blades, imparting a force to the blade surface and setting the rotor in motion. When a steady rotation speed has been reached, the speed is proportional to fluid velocity.

Turbine flow meters are used for the measurement of natural gas and liquid flow. Turbine meters are less accurate.

Vortex flow meter:

Another method of flow measurement involves placing a bluff body in the path of the fluid. As the fluid passes this bar, disturbances in the flow called vortices are created. The vortices

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trail behind the cylinder, alternatively from each side of the bluff body. The frequency at which these vortices alternate sides is essentially proportional to the flow rate of the fluid. Inside, atop, or downstream of the shedder bar is a sensor for measuring the frequency of the vortex shedding. This sensor is often a piezoelectric crystal, which produces a small, but measurable, voltage pulse every time a vortex is created. Since the frequency of such a voltage pulse is also proportional to the fluid velocity, a volumetric flow rate is calculated using the cross sectional area of the flow meter.

The frequency is measured and the flow rate is calculated by the flowmeter electronics

using the equation where ‘f’ is the frequency of the vortices, ‘L’ the characteristic length of the bluff body, ‘V’ is the velocity of the flow over the bluff body, and ‘S’ is the Strouhal number, which is essentially a constant for a given body shape within its operating limits.

Ultrasonic flow meter:

There are two main types of Ultrasonic flow meters: Doppler and transit time. While they both utilize ultrasound to make measurements, they measure flow by very different methods.

Ultrasonic transit time flow meters measure the difference of the transit time of ultrasonic pulses propagating in and against the direction of flow. This time difference is a measure for the average velocity of the fluid along the path of the ultrasonic beam. By using the absolute transit times both the averaged fluid velocity and the speed of sound can be calculated. With wide-beam illumination transit time ultrasound can also be used to measure volume flow independent of the cross-sectional area of the vessel or tube.

Ultrasonic Doppler flow meters measure the Doppler shift resulting from reflecting an ultrasonic beam off the particulates in flowing fluid. The frequency of the transmitted beam is affected by the movement of the particles; this frequency shift can be used to calculate the fluid velocity. For the Doppler principle to work there must be a high enough density of sonically reflective materials such as solid particles or air bubbles suspended in the fluid. This is in direct contrast to an ultrasonic transit time flow meter, where bubbles and solid particles reduce the accuracy of the measurement. Due to the dependency on these particles there are limited applications for Doppler flow meters.

One advantage of ultrasonic flow meters is that they can effectively measure the flow rates for a wide variety of fluids, as long as the speed of sound through that fluid is known. For example, ultrasonic flow meters are used for the measurement of such diverse fluids a liquid natural gas (LNG) and blood. One can also calculate the expected speed of sound for a given fluid; this can be compared to the speed of sound empirically measured by an ultrasonic flow meter for the purposes of monitoring the quality of the flow meter's measurements. A drop in quality is an indication that the meter needs servicing.

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Magnetic Flow Meter:

Magnetic flow meters use a magnetic field applied to the metering tube, which results in a potential difference proportional to the flow velocity perpendicular to the flux lines. The potential difference is sensed by electrodes aligned perpendicular to the flow and the applied magnetic field. The physical principle at work is Faraday's law of electromagnetic induction. The magnetic flow meter requires a conducting fluid and a non-conducting pipe liner. The electrodes must not corrode in contact with the process fluid.

Coriolis Mass flow meter:

A mass flow meter is a device that measures mass flow rate of a fluid traveling through a tube. The mass flow rate is the mass of the fluid traveling past a fixed point per unit time.

Fluid is being pumped through the mass flow meter. When there is mass flow, the tube twists slightly. The arm through which fluid flows away from the axis of rotation must exert a force on the fluid, to increase its angular momentum, so it bends backwards. The arm through which fluid is pushed back to the axis of rotation must exert a force on the fluid to decrease the fluid's angular momentum again, hence that arm will bend forward.

In other words, the inlet arm is lagging behind the overall rotation, and the outlet arm leads the overall rotation.

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Level Measurement:

Level measurement refers to instrumentation techniques designed to measure the height of a fluid or solid within a containing vessel.

Radar:

Radar is an object detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. For level measurement, It is mounted on the top of the vessel.

A radar system has a transmitter that emits radio waves called radar signals in predetermined directions. When these come into contact with an object they are usually reflected or scattered in many directions. Radar signals are reflected especially well by materials of considerable electrical conductivity. The radar signals that are reflected back towards the transmitter are the desirable ones that make radar work. If the level is increasing or decreasing, there is a slight equivalent change in the frequency of the radio waves, caused by the Doppler Effect.

Radar receivers are usually in the same location as the transmitter. Although the reflected radar signals captured by the receiving antenna are usually very weak, they can be strengthened by electronic amplifiers.

One way to measure the level is to transmit a short pulse of radio signal and measure the time it takes for the reflection to return. The level is total height of vessel minus one-half the product of the round trip time (because the signal has to travel to the target and then back to the receiver) and the speed of the signal. Since radio waves travel at the speed of light, accurate distance measurement requires high-performance electronics. In most cases, the receiver does not detect the return while the signal is being transmitted. Through the use of a duplexer, the radar switches between transmitting and receiving at a predetermined rate.

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Ultrasonic:

In this method ultrasonic sound waves are used in place of radio waves in the previous method. Ultrasonic wave is an oscillating sound pressure wave with a frequency greater than the upper limit of the human hearing range.

An ultrasonic level or sensing system requires no contact with the target. For many processes in general industries this is an advantage over inline sensors that may contaminate the liquids inside a vessel or tube or that may be clogged by the product.

Both continuous wave and pulsed systems are used. The principle behind a pulsed-ultrasonic technology is that the transmit signal consists of short bursts of ultrasonic energy. After each burst, the electronics looks for a return signal within a small window of time corresponding to the time it takes for the energy to pass through the vessel. Only a signal received during this window will qualify for additional signal processing.

It also works on the basis of Doppler Effect for level measurement.

Capacitive:

In this method, the property of a capacitor is used that the capacitance of the capacitor changes when a dielectric material (medium) is introduced between its two plates.

In this method, the two plates of the capacitor are at the top and bottom of the vessel. As level increases or decreases in the vessel, the capacitance changes. Due to which the voltage across the two plates of capacitor changes.

Thus, the capacitance of the capacitor is directly proportional to the level in the vessel.

Where, ‘C’ is the capacitance; ‘A’ is the area of cross section of the two plates; ‘εr’ is the relative static permittivity (sometimes called the dielectric constant) of the material between the plates (for a vacuum, εr = 1); ‘ε0’ is the electric constant (ε0 ≈ 8.854×10−12 F m–1); and ‘d’ is the separation between the plates.

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Valves:

A valve is a device that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. In an open valve, fluid flows in a direction from higher pressure to lower pressure.

Valves have many uses, including controlling water for Irrigation, industrial uses for controlling processes, residential uses such as on / off & pressure control to dish and clothes washers & taps in the home. Even aerosols have a tiny valve built in. Valves are also used in the military & transport sectors.

Valves are found in virtually every industrial process, including water & sewage processing, mining, power generation, processing of oil, gas & petroleum, food manufacturing, chemical & plastic manufacturing and many other fields.

In nature there are valves, for example one-way valves in Veins Controlling the blood circulation, & heart valves controlling the flow of blood in the chambers of the heart and maintaining the correct pumping action.

Valves may be operated manually, either by a handle, lever, pedal or wheel. Valves may also be automatic, driven by changes in pressure, temperature, or flow. These changes may act upon a diaphragm or a piston which in turn activates the valve, examples of this type of valve found commonly are safety valves fitted to hot water systems or boilers.

More complex control systems using valves requiring automatic control based on an external input (i.e., regulating flow through a pipe to a changing set point) require a positioner. A positioner will stroke the valve depending on its input and set-up, allowing the valve to be positioned accurately, and allowing control over a variety of requirements.

Pneumatic Valves:

These valves are actuated by the means of air (pneumatic control), that’s why these are referred as pneumatic valves.

In this type of valves, there is a continuous supply of air to the positioner through a thin pipe via Air Filter Regulator (AFR). Positioner controls the amount of air to be applied to valve based on the signal coming from control room.

The air is applied either to the top or to the bottom of the valve, depending upon whether it is Air-Fail Open (AFO) or Air-Fail Close (AFC).

If the valve is AFO, then the air is applied at the top of the valve, which forces the spring (mechanical) downwards to close the valve in normal conditions. How much the valve should be closed, this instruction is given from control room to the positioner which then controls the supply of air to the valve.

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In case of air fail, the continuous supply of air fails. In that case, there is no force from top on the spring of valve to close the valve. Thus, the valve opens fully whenever air fail condition occurs.

If the valve is AFC, then the air is applied at the bottom of the valve, which forces the spring upwards to open the valve in normal conditions. How much the valve should be opened, this is determined by positioner with the help of control room signal.

Whenever air fail condition occurs, there is no force on the spring and the piston falls down due to the spring force to close the valve. Thus, the valve is fully closed whenever air fail happens.

Manual Valves:

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In this type of valves, the actuator is controlled manually rather than giving signal from control room.

Valves may be operated manually, either by a handle, lever, pedal or wheel.

Whenever we have to open or close the valve, a person goes to the place where the valve is operating and then he performs the desired action by previously defined ways. Following are the different manual valves.

Control Valves:

A flow control valve regulates the flow or pressure of a fluid. Control valves normally respond to signals generated by independent devices such as flow meters or temperature gauges.

Control valves are normally fitted with actuators and positioners. Pneumatically-actuated globe valves and Diaphragm Valves are widely used for control purposes in many industries, although quarter-turn types such as (modified) ball, gate and butterfly valves are also used.

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Components of Control Valve:

Air Filter Regulator (AFR): As the name indicates, it filters the air and removes the small unwanted dust particles. The filtered air can also be regulated with the help of AFR, i.e. how much air should go to the positioner.

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Positioner: This is used for position control. Positioner receives air from AFR and it also receives a signal from control room regarding the amount of opening of valve. Positioner supplies that amount of air to the valve which fulfills the control room demand and positions the valve accordingly.

Solenoid Valve (SOV):

A solenoid valve is an electromechanically operated valve. The valve is controlled by an electric current through a solenoid: in the case of a two-port valve the flow is switched on or off; in the case of a three-port valve, the outflow is switched between the two outlet ports. Multiple solenoid valves can be placed together on a manifold.

Solenoid valves are the most frequently used control elements in fluidics. Their tasks are to shut off, release, dose, distribute or mix fluids. They are found in many application areas. Solenoids offer fast and safe switching, high reliability, long service life, good medium compatibility of the materials used, low control power and compact design.

There are many valve design variations. Ordinary valves can have many ports and fluid paths. A 2-way valve, for example, has 2 ports; if the valve is closed, then the two ports are connected and fluid may flow between the ports; if the valve is open, then ports are isolated. If the valve is open when the solenoid is not energized, then the valve is termed normally open (N.O.). Similarly, if the valve is closed when the solenoid is not energized,

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then the valve is termed normally closed. There are also 3-way and more complicated designs. A 3-way valve has 3 ports; it connects one port to either of the two other ports (typically a supply port and an exhaust port).

Solenoid valves are also characterized by how they operate. A small solenoid can generate a limited force. If that force is sufficient to open and close the valve, then a direct acting solenoid valve is possible.

In some solenoid valves the solenoid acts directly on the main valve. Others use a small, complete solenoid valve, known as a pilot, to actuate a larger valve. While the second type is actually a solenoid valve combined with a pneumatically actuated valve, they are sold and packaged as a single unit referred to as a solenoid valve.

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3. Process Control & Monitoring:

Distributed Control System (DCS):

A distributed control system (DCS) refers to a control system usually of a process or any kind of dynamic system, in which the controller elements are not central in location (like the brain) but are distributed throughout the system with each component sub-system controlled by one or more controllers.

DCS (Distributed Control System) is a computerized control system used to control the production line in the industry. The entire system of controllers is connected by networks for communication and monitoring.

A DCS typically uses custom designed processors as controllers and uses both proprietary interconnections and communications protocol for communication. Input and output modules form component parts of the DCS. The processor receives information from input modules and sends information to output modules. The input modules receive information from input instruments in the process (or field) and transmit instructions to the output instruments in the field. Computer buses or electrical buses connect the processor and modules through multiplexer or demultiplexers. Buses also connect the distributed controllers with the central controller and finally to the Human–machine interface (HMI) or control consoles. See Process automation system.

The elements of a DCS may connect directly to physical equipment such as switches, pumps and valves and to Human Machine Interface (HMI) via SCADA. The difference between DCS and SCADA is often subtle, especially with advances in technology allowing the functionality of each to overlap.

Distributed control systems (DCSs) are dedicated systems used to control manufacturing processes that are continuous or batch-oriented, such as oil refining, petrochemicals, central station power generation, fertilizers, pharmaceuticals, food and beverage manufacturing, cement production, steelmaking, and papermaking. DCSs are connected to sensors and actuators and use setpoint control to control the flow of material through the plant. The most common example is a setpoint control loop consisting of a pressure sensor, controller, and control valve. Pressure or flow measurements are transmitted to the controller, usually through the aid of a signal conditioning input/output (I/O) device. When the measured variable reaches a certain point, the controller instructs a valve or actuation device to open or close until the fluidic flow process reaches the desired setpoint. Large oil refineries have many thousands of I/O points and employ very large DCSs.

DCS at PNCP:

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The DCS of Yokogawa India Ltd ‘Centum CS3000’ is employed at Panipat Naphtha Cracker Project, which is the latest technology.

A Yokogawa DCS consists of functionally and geographically distributed digital controllers capable of executing from 1 to 256 or more regulatory control loops in one control box. The input/output devices can be integral with the controller or located remotely via a field network. These controllers have extensive computational capabilities and, in addition to proportional, integral, and derivative (PID) control, can generally perform logic and sequential control.

These DCS systems are designed with redundant processors to enhance the reliability of the control system. Most systems come with canned displays and configuration software which enables the end user to set up the control system without a lot of low level programming. This allows the user to better focus on the application rather than the equipment, although a lot of system knowledge and skill is still required to support the hardware and software as well as the applications. IOCL have dedicated groups that focus on this task. These groups are in many cases augmented by vendor support personnel and/or maintenance support contracts.

DCSs may employ one or more workstations (FCS or HIS) and can be configured at the workstation or by an off-line personal computer

Yokogawa Centum CS3000 Architecture

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Human Interface Station (HIS)

Graphics in Centum CS3000

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Programmable Logic Controller (PLC):

A Programmable Logic Controller, PLC or Programmable Controller is a digital computer used for automation of electromechanical processes. PLC is designed for multiple inputs and output arrangements.

The functionality of the PLC has evolved over the years to include sequential relay control, motion control, process control, distributed control systems and networking.

The scan time of PLC is less than that of DCS. That’s why PLC is usually employed for the Emergency Safe Shutdown System at PNCP. Whenever a critical error occurs, PLC is used to shut down the plant safely and immediately.

Allen Bradley PLC

Vibration Analysis (Bently Nevada):

Bently Nevada is a condition monitoring instrumentation company, providing services for sensors, systems, and monitoring machinery vibration. The offerings are primarily intended for assessing the mechanical condition of rotating equipment found in machinery-intensive industries such as oil and gas production. It is also employed at PNCP, Panipat.

it pioneered the eddy-current proximity probe, a sensor that revolutionized the measurement of vibration in high-speed turbomachinery by allowing the direct observation of the rotating shaft. The company also performed significant research in the field of rotordynamics, furthering knowledge of machinery malfunctions such as shaft cracks and

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fluid-induced instabilities. Its research also helped refine the equations used to describe vibratory behavior in rotordynamic systems.

In it different plots such as Shaft Centerline Plot, Bode plot, waterfall graph, color map etc. are plotted in System 1, which are analyzed by mechanical engineers.

Proximity Probe Bently Nevada

Bently Nevada 3500

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Plant Resource Manager (PRM):

Plant Resource Manager (PRM) is a plant asset management (PAM) software tool that works with production control systems CENTUM. With PRM and intelligent field devices, operators and maintenance personnel can monitor the condition of plant assets remotely. PRM’s diagnostic functions detect early signs of performance deterioration such as valve sticking and impulse line blocking. By helping curtail excessive preventive maintenance and enabling more predictive and proactive maintenance, PRM opens the way to asset predictability.

PRM is also a product of Yokogawa.

Device diagnostics and host-based advanced diagnostics are available for typical applications:

Typical applications:

Impulse line blocking diagnostics for differential pressure transmitters Heat/steam trace diagnostics for a group of pressure transmitters Electrode adhesion diagnostics for magnetic flowmeters Gland packing diagnostics for control valves Valve health monitoring

The ability to perform diagnoses online reduces the need for field inspections, and condition-based maintenance minimizes both planned and unplanned plant downtime. As a result, plant uptime can be maximized.

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