INDUSTRIAL TRAINING

Training done at

Alstom Projects India Ltd.Piping Engineering Department (Mechanical)

Plot No. 06, Sector – 127,Noida – 201301. (U.P.)

INDIA

Supervisor Submitted by :- Harshit AnandB.Tech (2nd yr, Mech)VIT, Vellore, T.N.

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ACKNOWLEDGEMENT

During my training at Alstom Power, I learnt a lot about Combined Cycle Power Plants, their erection and operation. I gained an in depth knowledge about the various mechanical aspects of a Combined Cycle Power Plant. I would like to express my sincere gratitude towards Mr.Sanjay Dhar for giving me this opportunity to undergo training at Alstom Power. I am also grateful to Mr. Munish Kumar , for giving me the opportunity to work under his able supervision.

I would also like to thank each and every member of the staff of the Piping Engineering Department at Alstom Power, who have helped me in every way possible during my training here. Their motivation & help was the key to success of my project. Under their competent guidance, encouragement and critical evaluation, I developed a new insight into my work. Not only have they helped me further my research and learning by providing me with research material and resources but they have also made my training at Alstom a wonderful and memorable experience.

Supervisor Harshit AnandDate: 10th June, 09

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INDEX

Page no.

Acknowledgement 1

About Alstom 5

Introduction 11

Combined Cycle Power Plant 13

Fundamental Theory and Operation 14

Major Components 15

Gas Compressor 17

Combustion Chamber 21

Gas Turbine 22

Heat Recovery Steam Generators 24

Steam Turbines 26

Condenser and Cooling System 28

Erection of a Power Plant 29

Piping 35

System Design Concerns 39

Valves 43

PID 46

PFD 51

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Legends of PID 52

Conclusion 57

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ALSTOM, the global leader in power and rail transport, is in the business of designing, building and servicing technologically advanced products and systems for the world's energy and transport infrastructure. It builds Power Plants and has supplied around 20% of the world’s total installed capacity in power generation. ALSTOM builds trains, which run on every continent. It has engineered and built the TGV, the world’s fastest train, Singapore’s automatic metro and almost the entire fleet of metros for the city of Paris. ALSTOM builds highly complex ships, which includes the recently completed Queen Mary 2, the largest cruise ship in the world The Company serves the energy market through its activities in the field of power generation and the transport market through its activities in rail and marine. ALSTOM's annual sales are around €17 billion. It employs 76,000 people in over 70 countries worldwide. The company serves the energy market through its activities in the fields of power generation, power transmission and distribution, power conversion and electrical contracting and the transport market through its activities in rail and marine.

ALSTOM offers its customers a complete range of innovative components, systems and services covering design and manufacture as well as commissioning and long-term maintenance and has unique expertise in systems integration, management of projects and application of advanced technologies. The ability to offer the broadest scope of power generation systems and equipment in the industry allows ALSTOM Power to deliver global solutions, from boilers, turbines and generators to the control systems, pollution control equipment, transformers and all the other systems needed to make a Power Plant run reliably, efficiently and with low emissions. In addition to state-of-the-art equipment and systems, ALSTOM Power provides extended core competencies in services and solutions. The control system technology is a corner stone of an efficient service support all along the plant life. ALSTOM offers a comprehensive capability, possessing the broadest scope of power generation systems, equipment and services in the industry. ALSTOM’s customers enjoy the maximum of options plus the most economical, environmentally friendly and advanced technologies.

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ALSTOM provides a wide range of new energy technologies. E.g. CFB boiler technology, low emissions firing systems, selective catalytic reduction, and flue gas desulphurisation and supercritical cycles. Environmentally friendly solutions are also available for noise control and effluents, which meet the most stringent worldwide regulations. Delivering the products and services, whether a utility, an independent power producer, or you are in industry, ALSTOM can deliver the products and services.

Turnkey Plants

Gas/steam/hydro

Turbines

Gas/steam/hydro

Generators

Gas/steam/hydro

Boilers

For power generation and industry

Air Preheaters and Heat Exchangers

Air Pollution Control Systems

Power Plant Control

Customer Services

Complete portfolio of service products

Modernization of Power Plant

Long-term operation and maintenance

ALSTOM In India:-

ALSTOM is the majority shareholder in ALSTOM Projects India Ltd. In India, ALSTOM is active in two major areas of businesses i.e. Power and Transport. Commencing its operations in Calcutta in the 1910s and later in Chennai in the 1950s, ALSTOM in India traces its lineage to English Electric, CEGELEC, AEI, GEC ALSTHOM, ASEA, HBB, FLAKT and ABB, drawing its strengths from technologies developed over the years by

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these companies. ALSTOM has been a long-term player in India in the energy and transport infrastructure business, supplying critical electrical and industrial equipment including boilers and turbines and pollution control equipment for Power Plants, and transmission & distribution equipment. With its significant presence in the transport sector in India, ALSTOM provides railway equipment and technology solutions. The Industrial equipment division with annual sales of 15 Million Euros manufactures rotating machinery, motors, industrial and domestic fans.

ALSTOM in India helps generate nearly 40% of the total power produced in the country. In India, ALSTOM companies have together a turnover of about 280 Million Euros with about 6,500 employees.

In India, ALSTOM is active in two major areas of businesses:

Power:-

In Karnataka the Power Sector forms a major part of ALSTOM's business operations in India, accounting for 59 per cent of its total revenue through its activities as an Equipment Supplier, Engineering Procurement and Construction Contractor and Products/Services supplier for central and state public sector utilities or Independent Power Producers.

ALSTOM's power sector in India specializes in designing & supplying integrated and cost efficient Steam, Combined Cycle and Hydro Power Plants.

This includes their engineering, procurement & construction; development and supply of air pollution control systems and equipment. In addition, it also offers a full range of services in spare parts, repairs & maintenance to improve the reliability and availability of the plants.

Alstom's power sector also offers a complete range of utility & industrial boilers in India. It has manufacturing locations at Durgapur in West Bengal and Shahabad

With manufacturing location at Kolkata for environment control systems, Alstom's power sector

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in India employs more than 1800 people, with annual sales in excess of 125 million euro. A joint venture between Alstom and NTPC has a mandate for the total renovation and modernization (R&M) business in India and the SAARC countries for thermal Power Plants and thermal based utilities.

Transport:-

ALSTOM's Transport sector is among the leaders in rail transport in the world. Its TGV needs no introduction.

ALSTOM's transport sector in India is equipped with RDSO approved 'state-of-the-art' factory at Coimbatore equipped for manufacture, supply, assembly and testing of Power Electronics & Traction Equipment, Signaling products such as Point Machines, Audio Frequency Track Circuits etc. The company manufactures world-class traction drives, auxiliary converters, control electronics, electro-mechanical products and safety systems. The factory is ISO 9001- 2000 and ISO - 14001 certified and is located in the industrial belt with access to component suppliers. The company also has a world-class software centre at Bangalore handling design of Train Control System and Application Software.

Being members of the ALSTOM Transport Group, there is access to global technologies. ALSTOM's global transport product range includes TGVs and High Speed Tilting Train for industry operations, tramways and metros for urban transit and locomotives, and freight wagons. It also provides train control systems, train life management services, the railroad maintenance and turnkey or full concession transportation system solutions.

Research & Innovation :- ALSTOM regards competitive technology as a key element of its business strategy, both to meet the quality and efficiency expectations of its customers and to achieve its own financial targets.Research and Development efforts are driven essentially by current and future market needs in our product areas. This is why our R&D resources are managed by our businesses, with programs and priorities being defined and refined by them

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We are continuously improving the performance, functionality and cost-effectiveness of our products, both through developing new technical solutions or innovative application of existing elements. Current examples include:

Information and communication technologies are enabling major advances in the large systems we design, including new means of train signaling, novel designs of electrical substation monitoring and control, and new services such as remote maintenance or trading in de-regulated electricity markets.

Power electronic systems are already well known, but development of new circuit concepts continues to expand their application and penetration, while new materials such as silicon carbide and diamond promise further step changes in the future. We can now see the real possibility that a majority of the world's electricity will be actively managed by power electronics in the future.

New materials continue to emerge. Gaining understanding on their behaviour remains a key technological activity, and their application to our product is a critical factor in improving performance and cost-effectiveness.

Advanced engineering simulation systems, which are key to rapid design and development timescales. Developments made here are enabling us to improve the lifetime of mechanical components in steam turbines, and the power outputs of electrical machines, all of which translate into lower costs for our clients. We continue to reduce the environmental impact of our products. Specific examples include:

1. Reducing atmospheric emissions through improved power generation efficiencies, novel combustion systems which inhibit NOx formation in gas turbines, new boiler schemes for clean coal combustion, and even genuinely zero-emission systems which capture all the CO2 from fuel,

2. Finding ways to minimise the noise generated by the operation of plant and trains, by understanding how it is generated so it can be efficiently inhibited,

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Protecting the marine environment through initiatives such as the 'clean' passenger ship which avoids the dumping of waste, or the Oil Sea Harvester which can efficiently collect spilt oil,

3. Making more efficient, more accessible, more reliable public transport systems which can provide an attractive travel option to other means,

4. Embedding environmental impact analysis into the design process, so that products can be designed for minimal whole life environmental cost

Combined CyclePower Plant

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Introduction

Gas Turbine and Combined Cycle Power Plant

During the last three decades, the development of gas turbines has made a lot of progress. Also due to environmental legislation, gas, as a relatively low-pollutant fuel, encourages the gas turbine manufacturers to specially adapt gas turbines to power plant requirements and to improve their thermal efficiency.

The modern power gas turbine is a high-technology package that is comprised of a compressor, combustor, power turbine, and generator, as shown in the figure of a Simple-Cycle Gas Turbine.

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In a gas turbine, large volumes of air are compressed to high pressure in a multistage compressor for distribution to one or more combustion gases from the combustion chambers power an axial turbine that drives the compressor and the generator before exhausting to atmosphere. In this way, the combustion gases in a gas turbine power the turbine directly, rather than requiring heat transfer to a water/steam cycle to power a steam turbine, as in the steam plant.

Gas Turbine Cycle

The figure below represents the thermo-dynamic cycle in a gas turbine power pant (Brayton’s Cycle).

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Combined Cycle Power Plant

When two thermal cycles are combined in a single power plant, the efficiency that can be achieved is higher than that of one cycle alone. Normally, when two cycles are combined, the cycle operating at higher temperature level is called the ‘topping cycle’. The waste heat it produces is then used in a second process that operates at a lower temperature level and is therefore called the ‘bottoming cycle’.

The flue gas leaving the gas turbine after expansion in an open process still contains a lot of thermal energy, which should be used efficiently. This can be done by installing a water/steam circuit with a steam turbine downstream of the gas turbine process.

The Combined Cycle Power Plant (CCPP) utilizing the Brayton Cycle gas turbine and the Rankine Cycle steam system with air and water as working fluids achieves efficient, reliable, and economic power generation.

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The combination of the gas turbine Brayton Cycle and the steam power system Rankine Cycle complement each other to form efficient combined-cycles. The Brayton Cycle has high source temperature and rejects heat at a temperature that is conveniently used as the energy source for the Rankine Cycle. Other working fluids (organic fluids, potassium vapor, mercury vapor, and others) have been applied on a limited scale.

Fundamental Theory and Operation

Air and water as working fluids have achieved widespread commercial application due to:

1. High thermal efficiency through application of two complementary thermodynamic cycles.

2. Heat rejection from the Brayton Cycle (gas turbine) at a temperature that can be utilized in a simple and efficient manner.

3. Working fluids (water and air) are readily available, inexpensive, and nontoxic.

In combined cycle power generation systems, the gas turbine is driven by high temperature gas produced by combustion of fuels such as natural gas,

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and the steam turbine turned by steam produced by the exhaust heat of the combustion. The generator is driven by the combined power of these two sub systems to generate power.

Combined Cycle

Figure shows a combination of both the cycles – Topping with Brayton’s Cycle and & Bottoming with Rankine’s Cycle.

Major Components

The Air Compressor to compress the air for combustion of natural gas,

The Burner to produce high temperature and high-pressure gas by burning natural gas,

The Gas Turbine, which rotates the generator by the thrust of combustion gas,

The HRSG (Heat Recovery Steam Generator) that produces steam by recovered heat from exhaust gas discharged from the gas turbine,

The Steam Turbine driven by the steam produced by HRSG,

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The Condenser as heat sink to complete the cycle.

Schematic Diagram of basic Combined Cycle Power Plant CCPP Operation

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In this system Gas dampers are often provided so the gas turbine exhaust can bypass the heat recovery boiler allowing the gas turbine to operate if the steam unit is down for maintenance.

Sometimes as many as four gas turbines with individual boilers may be associated with a single steam turbine. The gas turbine, steam turbine, and generator may be arranged as a single shaft design, or a multi-shaft arrangement may be used with each gas turbine driving a generator and exhausting into its heat recovery boiler with all boilers supplying a separate steam turbine and generator.

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Combined Cycle Shaft Arrangement

The single shaft arrangement in a combined cycle power plant functions in the same way as the multiple shaft arrangement. The most important difference is the application of self shifting and synchronizing (SSS) clutch. It permits the Steam Turbine to be accelerated and to be connected to the Alternator, already being driven by the GT.

The SSS clutch engages automatically as soon as the torque from the ST shaft becomes positive, that is as soon as the rotational speed of the ST tends to over table that of the alternator. It disengages automatically as soon as the torque of the ST shaft becomes negative.

Gas Compressor

A Gas Compressor is a mechanical device that increases the pressure of a gas by reducing its volume.

Compressors are similar to pumps: both increase the pressure on a fluid and both can transport the fluid through a pipe. As gases are compressible, the compressor also reduces the volume of a gas. Liquids are relatively incompressible, so the main action of a pump is to pressurize and transport liquids.

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Centrifugal compressorsCentrifugal compressors use a muskan rotating disk or impeller in a shaped housing to force the gas to the rim of the impeller, increasing the velocity of the gas. A diffuser (divergent duct) section converts the velocity energy to pressure energy. They are primarily used for continuous, stationary service in industries such as oil refineries, chemical and petrochemical plants and natural gas processing plants. Their application can be from 100 horsepower (75 kW) to thousands of horsepower. With multiple staging, they can achieve extremely high output pressures greater than 10,000 psi (69 MPa).

Diagonal or mixed-flow compressorsDiagonal or mixed-flow compressors are similar to centrifugal compressors, but have a radial and axial velocity component at the exit from the rotor. The diffuser is often used to turn diagonal flow to the axial direction. The diagonal compressor has a lower diameter diffuser than the equivalent centrifugal compressor.

Axial-flow compressorsAxial-flow compressors are dynamic rotating compressors that use arrays of fan-like aerofoils to progressively compress the working fluid. They are used where there is a requirement for a high flow rate or a compact design.

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Axial compressors can have high efficiencies; around 90% polytropic at their design conditions. However, they are relatively expensive, requiring a large number of components, tight tolerances and high quality materials. Axial-flow compressors can be found in medium to large gas turbine engines, in natural gas pumping stations, and within certain chemical plants.

Reciprocating compressors

Reciprocating compressors use pistons driven by a crankshaft. They can be either stationary or portable, can be single or multi-staged, and can be driven by electric motors or internal combustion engines. Small reciprocating compressors from 5 to 30 horsepower (hp) are commonly seen in automotive applications and are typically for intermittent duty. Larger reciprocating compressors well over 1,000 hp (750 kW) are still

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commonly found in large industrial and petroleum applications. Discharge pressures can range from low pressure to very high pressure (>6000 psi or 41.4 MPa). In certain applications, such as air compression, multi-stage double-acting compressors are said to be the most efficient compressors available, and are typically larger, noisier, and more costly than comparable rotary units

Rotary screw compressors

Rotary screw compressors use two meshed rotating positive-displacement helical screws to force the gas into a smaller space. These are usually used for continuous operation in commercial and industrial applications and may be either stationary or portable. Their application can be from 3 horsepower (2.2 kW) to over 1,200 horsepower (890 kW) and from low pressure to very high pressure (>1200 psi or 8.3 MPa).

Rotary vane compressorsRotary vane compressors consist of a rotor with a number of blades inserted in radial slots in the rotor. The rotor is mounted offset in a larger housing which can be circular or a more complex shape. As the rotor turns, blades slide in and out of the slots keeping contact with the outer wall of the housing. Thus, a series of decreasing volumes is created by the rotating blades. Rotary Vane compressors are, with piston compressors one of the oldest of compressor technologies.

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Scroll compressors

A scroll compressor, also known as scroll pump and scroll vacuum pump, uses two interleaved spiral-like vanes to pump or compress fluids such as liquids and gases. The vane geometry may be involute, archimedean spiral, or hybrid curves. They operate more smoothly, quietly, and reliably than other types of compressors in the lower volume range

Often, one of the scrolls is fixed, while the other orbits eccentrically without rotating, thereby trapping and pumping or compressing pockets of fluid or gas between the scrolls.

Diaphragm compressorsA diaphragm compressor (also known as a membrane compressor) is a variant of the conventional reciprocating compressor. The compression of gas occurs by the movement of a flexible membrane, instead of an intake element. The back and forth movement of the membrane is driven by a rod and a crankshaft mechanism. Only the membrane and the compressor box come in touch with the gas being compressed.

Diaphragm compressors are used for hydrogen and compressed natural gas (CNG) as well as in a number of other applications.

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Combustion Chamber

A combustor is a component or area of a gas turbine, ramjet or pulsejet engine where combustion takes place. It is also known as a burner or flame can depending on the design. In a gas turbine engine, the main combustor or combustion chamber is fed high pressure air by the compression system and feeds the hot exhaust into the turbine components of the gas generator.

Combustors are designed to contain and control the burning fuel-air mixture. The combustor normally consists of three components: an outer casing that acts as a high pressure container, the combustion chamber itself which contains the flame and the fuel injection system.

Air leaving the compressor must first be slowed down and then split into two streams. The smaller stream is fed centrally into a region where atomized fuel is injected and burned with a flame held in place by a turbulence-generating obstruction. The larger, cooler stream is then fed into the chamber through holes along a “combustion liner” (a sort of shell) to reduce the overall temperature to a level suitable for the turbine inlet. Combustion can be carried out in a series of nearly cylindrical elements spaced around the circumference of the engine called cans, or in a single annular passage with fuel-injection nozzles at various circumferential

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positions. The difficulty of achieving nearly uniform exit-temperature distributions in a short aircraft combustion chamber can be alleviated in stationary applications by longer chambers with partial internal reversed flow.

Gas Turbine

Gas turbine, also called a combustion turbine, is a rotary engine that extracts energy from a flow of combustion gas. It has an upstream compressor coupled to a downstream turbine, and a combustion chamber in-between.

Energy is added to the gas stream in the combustor, where air is mixed with fuel and ignited. Combustion increases the temperature, velocity and volume of the gas flow. This is directed through a nozzle over the turbine's blades, spinning the turbine and powering the compressor.

Energy is extracted in the form of shaft power, compressed air and thrust, in any combination, and used to power aircraft, trains, ships, generators, and even tanks.

Theory of operationGas turbines are described thermodynamically by the Brayton cycle, in which air is compressed isentropically, combustion occurs at

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constant pressure, and expansion over the turbine occurs isentropically back to the starting pressure.

In practice, friction and turbulence cause:

Non-isentropic compression: for a given overall pressure ratio, the compressor delivery temperature is higher than ideal.

Non-isentropic expansion: although the turbine temperature drop necessary to drive the compressor is unaffected, the associated pressure ratio is greater, which decreases the expansion available to provide useful work.

Pressure losses in the air intake, combustor and exhaust: reduces the expansion available to provide useful work.

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Heat Recovery Steam Generators

HRSG stands for Heat Recovery Steam Generator. A HRSG is a type of boiler, which uses energy from gas turbine exhaust as its heat source to produce steam.

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Fuel In

ExhaustGas

Gas Turbine HRSG

G

Condenser

SteamTurbine

Feed Pump

Air In

HRSG’s are used in:

Cogeneration plants to provide steam for industrial processes.

Combined cycle power plants to provide steam to a steam turbine.

Differences Between HRSGs and Conventional Boilers

HRSG’s use exhaust from gas turbine as heat source so do not need a firing system (unless supplementary fired).

HRSG’s do not use fans (draft is from gas turbine exhaust).

HRSG’s generate steam at multiple pressure levels to improve heat recovery efficiency.

Heat transfer is by convection rather than radiation.

HRSG’s do not use membrane wall construction.

HRSG’s use finned tubes to maximise heat transfer.

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Steam Turbine

A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884.

It has almost completely replaced the reciprocating piston steam engine primarily because of its greater thermal efficiency and higher power-to-weight ratio. Because the turbine generates rotary motion, it is particularly suited to be used to drive an electrical generator – about 80% of all electricity generation in the world is by use of steam turbines. The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency through the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible process.

Principle of Operation and DesignAn ideal steam turbine is considered to be an isentropic process, or constant entropy process, in which the entropy of the steam entering the turbine is equal to the entropy of the steam leaving the turbine. No steam turbine is truly “isentropic”, however, with typical isentropic efficiencies ranging from 20%-90% based on the application of the turbine. The interior of a turbine comprises several sets of blades, or “buckets” as they are more commonly referred to. One set of stationary blades is connected to the casing and one set of rotating blades is connected to the shaft. The sets intermesh with certain minimum clearances, with the size and configuration of sets varying to efficiently exploit the expansion of steam at each stage.

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Turbine EfficiencyTo maximize turbine efficiency, the steam is expanded, generating work, in a number of stages. These stages are characterized by how the energy is extracted from them and are known as impulse or reaction turbines. Most modern steam turbines are a combination of the reaction and impulse design. Typically, higher pressure sections are impulse type and lower pressure stages are reaction type.

Impulse TurbinesAn impulse turbine has fixed nozzles that orient the steam flow into high speed jets. These jets contain significant kinetic energy, which the rotor blades, shaped like buckets, convert into shaft rotation as the steam jet changes direction. A pressure drop occurs across only the stationary blades, with a net increase in steam velocity across the stage.

As the steam flows through the nozzle its pressure falls from steam chest pressure to condenser pressure (or atmosphere pressure). Due to this relatively higher ratio of expansion of steam in the nozzle the steam leaves the nozzle with a very high velocity. The steam leaving the moving blades is a large portion of the maximum velocity of the steam when leaving the nozzle. The loss of energy due to this higher exit velocity is commonly called the "carry over velocity" or "leaving loss".

Reaction TurbinesIn the reaction turbine, the rotor blades themselves are arranged to form convergent nozzles. This type of turbine makes use of the reaction force produced as the steam accelerates through the nozzles formed by the rotor. Steam is directed onto the rotor by the fixed vanes of the stator. It leaves the stator as a jet that fills the entire circumference of the rotor. The steam then changes direction and increases its speed relative to the speed of the blades. A pressure drop occurs across both the stator and the rotor, with steam accelerating through the stator and decelerating through the rotor, with no net change in steam velocity across the stage but with a decrease in both pressure and temperature, reflecting the work performed in the driving of the rotor.

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Condenser and cooling system

The condensers and cooling systems involved in condensing the exhaust steam from a steam turbine and transferring the waste heat away from the power station.

Condensers

The function of the condenser is to condense exhaust steam from the steam turbine by rejecting the heat of vaporisation to the cooling water passing through the condenser. The temperature of the condensate determines the pressure in the steam/condensate side of the condenser. This pressure is called the turbine backpressure and is usually a vacuum. Decreasing the condensate temperature will result in a lowering of the turbine backpressure. Note: Within limits, decreasing the turbine backpressure will increase the thermal efficiency of the turbine.

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Erection ofA

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Power Plant

METHODS AND TECHNIQUES USED IN

POWER STATION ERECTION

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The Process of erection of a 500 MW unit is a very complex process. Work involved in the erection of a 500 MW unit are very large and the Techniques are so varied that it is quiet difficult to discuss them all in details. The following figures will give an idea of the work involved and are to be completed for the commissioning of one unit of 500 MW.

i) Earth Work - approx. 10 lacs M3

ii) Concreting Work - 1.1 lac M3

iii) Structural erection - 120000 tons

iv) Mechanical and Electrical equipments - 18000 tons

v) Length of piping - approx. 130 Krns.

vi) Length of cabling - 350 to 400 Krns.

vii) Brick work - 40,000 to 50,000 sq. m

Methods & techniques for certain part of erection activities are commonly applied whereas for certain equipment exclusive in nature, erection personnel are required to be educated thoroughly before proceeding with the erection.

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In fact the erection activity is very broad in nature and does cover some peripheral activities which are not directly connected with actual erection job but are desirable in order to have a systematic output. These activities along with the erection activities are tabulated in the sequence it is required to be followed.

1. Transportation, Inspection & Storage :

This activity forms the input for next activity. Once the material is received at site all parts are checked with the help of packing list 1\2 slip sent with the consignment and relevant drawing if necessary. Missing\shortage\damaged items are listed under respective heads and action is taken to replenish\repair the same. Nearly 30,000MT, materials are installed in one unit at 500 MW Boiler.

After inspection is carried out, the components received are stored/stocked properly in order so that their life is not reduced due to prolonged storage and retrieval at the time of requirement is also easy. Long storage is done with specific preservation methods which is time dependent. Storing may be done outside or inside depending on the nature of the component. Preservation methods which are commonly adopted are,

a) Rust Preventive

b) Corrosion inhibitor

c) Sillicagel application

d) Spray reel application etc. 2 Preparation for erection

2. Preparation for erection

The following details shall be thoroughly studied with the individual contracts reg. size, range application, and scope of supply with reference to the product offered.

Preparation for erection:

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i) System lay out

ii) Assembly drugs. of various equipment

iii) Performance drugs/manuals

iv) Installation drawings

v) Foundation plans

vi) Scope of supply of the contracts

vii) Shipping lists with respect to erection drawings

After ensuring the above, following are to be observed.

1) Before proceeding with erection adequate arrangements for safe handling of equipment is to be made at work site. This may include tools, tackles rigging and handling facilities required for erection. Special attention is to be paid for the shape/size/wt. of the components as well as the space limitations while proceeding with installation.

2) In line with the construction management philosophy erection department is required to be actively involved in the checking of foundation before it is cast and after it is cast for any defects which maybe detrimental for the equipment. Performance in the longrun as well as cause difficulty during the course of erection.

3) The material received earlier at stores and stocked properly are to be retrieved as per the sequence of erection to be done with ref. to drawings/manuals etc.

4) The preservatives used during storage purposes are to be cleaned thoroughly and the item be made ready for assembly/erection.

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5) Finally foundations is taken over with all respective dimensions properly checked with limits / tolerance specified in the drawing.

Attention should be paid to presence of match marks for components. For large components which require pre-assembly separate area is identified where such activities can be carried out. After pre-assembly the components are transported with care to the foundation for erection.

6) For placing any equipment/column structure on the foundation a base plate is first erected on to the foundation on packing plates which takes care of matching of base plate with the foundation as well as for alignment of the equipment/column structure.

This matching is achieved by matching the pack or plates or blue matching as may be the level of requirement.

7) Once the first part of the equipment is erected and leveled / aligned, the equipment is grouted i.e. the space below the base plate and the foundation is filled with suitable grout mixture to have a compact filling with good bounding with the foundation.

8) The next step is to go ahead with further erection as per the standard erection procedure as laid out.

System Configuration of a Combined Cycle Power Plant

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Layout of Combined Cycle Power Plant

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Piping

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PIPING

Piping systems are like arteries and veins. They carry the lifeblood of modern civilization. In a modern city they transport water from the sources of water supply to the points of distribution; convey waste from residential and commercial buildings and other civic facilities to the treatment facility or the point of discharge. Similarly, pipelines carry crude oil from oil wells to tank farms for storage or to refineries for processing. The natural gas transportation and distribution lines convey natural gas from the source and storage tank forms to points of utilization, such as power plants, industrial facilities, and commercial and residential communities. In chemical plants, paper mills, food processing plants, and other similar industrial establishments, the piping systems are utilized to carry liquids, chemicals, mixtures, gases, vapors, and solids from one location to another.

The Fire protection piping networks in residential, commercial, industrial, and other buildings carry fire suppression fluids, such as water, gases, and chemicals to provide protection of life and property. The piping systems in Combined Cycle Power Plants convey high-pressure and high-temperature steam to generate electricity. Other piping systems in a power plant transport high- and low-pressure water, chemicals, low-pressure steam, and condensate. sophisticated piping systems are used to process and carry hazardous and toxic substances. The storm and wastewater piping systems transport large quantities of water away from towns, cities, and industrial and similar establishments to safeguard life, property, and essential facilities.

In health facilities, piping systems are used to transport gases and fluids for medical purposes. The piping systems in laboratories carry gases, chemicals, vapors, and other fluids that are critical for conducting research and development. In short, the piping systems are an essential and integral part of our modern civilization just as arteries and veins are essential to the human body.

The design, construction, operation, and maintenance of various piping systems involve understanding of piping fundamentals, materials, generic and specific design considerations, fabrication and installation, examinations, and testing and inspection requirements, in addition to the local, state and federal regulations.

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Ques. What should a Piping Engineer should know about ?

Ans. Piping engineer requires not only wide engineering knowledge - not necessarily in depth, but certainly in understanding - but he must also have an understanding of engineering economics and costs, of metallurgy, of methods of pipe fabrication and erection. He must have some knowledge of industrial chemistry and chemical engineering in addition to a sufficient knowledge of mechanical, civil, electrical and instrument engineering so as to discuss requirements and problems with specialists in these fields. He should be co- operative, able to communicate effectively, lead or take part in teamwork, be alive to the application of new methods, materials and designs. He must be aware of standards, codes and practices.

There are several aspects of engineering technology, which the piping engineer must know something about – at least sufficiently to discuss rationally, any particular subject with specialists concerned. More importantly, he must have sufficient broad knowledge to know that certain conditions can arise at the early stages of plant design, where lack of awareness can cause difficulties and even disasters.

A fairly good knowledge of structural engineering is a must. Piping in operation is always in movement and subjected to forces and moments with consequent reactions on Interconnections such as pumps, compressors and equipment in general, and on structures and related piping. Lack of knowledge can cause errors sufficient to cause machine or equipment breakdown or to overstress and even cause collapse of structures.

A good knowledge of safety codes and practices is also essential.

Above all, a piping engineer should be very well conversant with drafting procedures and practices.

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Typical Piping Isometric Drawing

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System Design Concerns

1.1 Main steam, hot reheat, cold reheat, HP, LP, process, auxiliary steam, gland steam

- Large pipe

- Large thickness of insulation

- Large amount of thermal growth

- Pipe slopes

- Need to account for flexibility

- Engineered hangers

- Large in size & often needed maintenance of valves/desuperheating valves

- Safety valves/silences

- Flow nozzles

- Steam blow

- Code pipe

- Turbine water induction

- Interface points on turbine

- Allowable forces and moments on turbine & HRSG Header nozzles

1.2 Main HP & LP feedwater

- Large pipe

- Large thickness of insulation

- Large amount of thermal growth

- Need to account for flexibility

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- Engineered hangers

- Large in size & often needed maintenance of valves

- Safety valves/silences

- Flow nozzles

- Steam blow

- Code pipe

- Turbine water induction

- Interface points on BFP

- Allowable forces and moments on BFP & HRSG Header nozzles

1.3 Circulating water

- Large non-standard pipe

- Need to account for flexibility

- Engineered hangers

- Large in size & often needed maintenance of valves

- Flow model of system configuration

- Thrust blocks in yard.

1.4 HRSG blowdowns

- Large thickness of personnel protection insulation

- Large amount of thermal growth

- Need to account for flexibility

- Engineered hangers

- Large amount of small pipe interfaces to headers which must slope for drainage.

- HP flash tank and LP blowdown tank location

- Blowdown valve locations

1.5 Steam drains

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- Large thickness of personnel protection insulation

- Large amount of thermal growth

- Need to account for flexibility

- Engineered hangers

- Large amount of small pipe interfaces to headers which must slope for drainage.

- Location of condenser nozzles to provide slope for drainage

- Turbine water induction

- Drain valve locations

1.6 Fuel gas

- Governed by codes

- Limit hazardous classification area vendor skid equipment may have already been purchased which may not be rated for hazardous area.

- Large number of miscellaneous vents/reliefs

- Engineered hangers

1.7 Fuel oil

- Environmental concerns

- Guard pipe or containment may be required.

- Should not run above hot steam lines if need be drip shields above steam lines should be used.

1.8 Turbine Lube oil

- Environmental concerns

- Guard pipe or containment may be required.

- Should not run above hot steam lines if need be drip shields above steam lines should be used turbine lube oil

1.9 Control & Instrument air

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- Sloped headers

- Coverage

- Defining all users

1.10 Ammonia, Chemical feed

- Environmental concerns

- Guard pip or containment may be required.

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Valves

Valve functions can be defined as ON/OFF service, throttling service (flow control), prevention of reverse flow (or back flow), pressure control, regulation and pressure relief. Valves can be classified as either linear (gate valve) or rotary (ball valve) based on the action of the closure member. They are also classified by the shape of their closure member such as gate, globe, butterfly, ball, plug, diaphragm, pinch, and check. Their primary function, however, is to control the flow of liquids and gases, including plain water, corrosive fluids, steam, toxic gases, or any number of fluids with widely varying characteristics. Valves must also be able to withstand the pressure and temperature variations of the systems in which they are used. Some valves on combined water service mains, and those handling flammable material, may be required to be fire safe or approved for fire protection use.

CODES AND STANDARDS

The following standards apply to valve construction:

1. AWWA C 500: gate valves for water and sewage systems

2. AWWA C 504: rubber seated ball valves

3. MSS SP 67: butterfly valves

4. MSS SP 80: bronze gate, globe, angle, and check valves

VALVE COMPONENTS

The following are the primary components of a valve.

1. A valve body is the housing for all the internal working components of a valve and it contains the method of joining the valve to the piping system.

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2. The closure element, known as the disk or plug, is a valve component that, when moved, opens or closes to allow the passage of fluid through the valve. The mating surface of the disk bears against the seat.

3. The actuator is a movable component that, when operated, causes the closure element to open or close.

4. The stem is a movable component that connects the actuator to the closure element.

5. The bonnet is a valve component that provides a leak proof closure for the body through which the stem passes and is sealed.

6. The seat is a component that provides a surface capable of sealing against the flow of fluids in a valve when contacted by a mating surface on the disk. The seat is attached to the valve body.

7. The stuffing box is the interior area of the valve between the stem and the

bonnet that contains the packing.

8. Packing is the material that seals the stem from leaking to the outside of the valve. The packing is contained by the packing nut on the bonnet.

9. The backseat is a seat in the bonnet used in the fully open position to seal the valve stem against leakage into the packing. A bushing on the stem provides the mating surface. Backseating is useful if the packing begins to leak and it provides a means to prevent the stem from being ejected from the valve. Backseating is not provided on all valves.

10. The stroke of a closure member is the distance the member must travel from the fully opened to the fully closed position.

FUNCTION OF VALVES

The design of the valves is done in such a way as to perform any of the above functions. The type of valves used can be classified in the following categories.

1.0 ISOLATION

1.1 Gate Valves

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1.2 Ball Valves

1.3 Plug Valves

1.4 Piston Valves -

1.5 Diaphragm Valves

1.6 Butterfly Valves -

1.7 Pinch Valves

2.0 REGULATION

2.1 Globe Valves

2.2 Needle Valves

2.3 Butterfly Valves

2.4 Diaphragm Valves

2.5 Piston Valves

2.6 Pinch Valves

3.0 NON-RETURN

3.1 Check Valves

4.0 SPECIAL PURPOSE

4.1 Multi-Port Valves

4.2 Flush Bottom Valves

4.3 Float Valves

4.4 Foot Valves

4.5 Line Blind Valves

4.6 Knife Gate Valves

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KAJ System

Piping and Instrumentation Diagrams ( PID )

FeedWater Preheater System

Fuel Gas System

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HP / IP Feed water Pump System

HP Turbine By-Pass

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Main Steam System

LP Turbine By-Pass

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Main Condensate System

IP Turbine By-Pass

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Air Removal System

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Process Flow Diagram ( PFD )

The Process Flow Diagram for the above KAJ ( Reference Plant ) System is given as :-

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Steam Turbine

Evaporator

Economizer

LP

HPIP

HP LP

IP

Steam Ejector

Condenser

CEPGland Steam Condenser

DeaeratorFeed Water Tank

FW

Pump

Legends

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Conclusion

The Purpose of this Training was to:-

Gain a general overview of Combined Cycle Power Plants and their working

To study about the basic Combined Cycle Power Plant cycle and various arrangements used in the Combined Cycle Power Plant.

To study the Theoretical side of a Combined Cycle Power Plant and how it is applicable in the real world scenario.

The above objectives are met with greater ease and all the points are discussed in a regularized manner.

This report covers a basic familiarization of a few of the various Mechanical components used in a Combined Cycle Power Plant and operation of a Combined Cycle Power Plant.

In the later part of the Report more stress is given on the Methods and Techniques of Erection of a Power Plant, in short, the practical applications of the theoretical knowledge we gained during the training.

The basics of the Combined Cycle Power Plants have been studied thoroughly with its fundamental theory and Operations and their major components are discussed.

Fundamental theory of Piping Techniques is understood and ways of interpreting a Piping and Instrumentation Diagram (PID) is learned. Knowledge of different types of valves is also gained. Also the basic knowledge of PDMS (Plant Design Management System) software is gained during the training period.

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