ME6701 POWER PLANT ENGINEERING L T P C 3 0 0 3 …Draught system, Feed water treatment. Binary...

REGULATION : 2013 ACADEMIC YEAR : 2018-2019

JIT-JEPPIAAR/MECH/Mr.D.ARUNKUMAR/IV Yr/SEM 07/ME6701/POWER PLANT ENGINEERING/UNIT 1-

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ME6701 POWER PLANT ENGINEERING L T P C

3 0 0 3

OBJECTIVES:

• Providing an overview of Power Plants and detailing the role of Mechanical Engineers in

their operation and maintenance.

UNIT I COAL BASED THERMAL POWER PLANTS 10

Rankine cycle - improvisations, Layout of modern coal power plant, Super Critical Boilers,

FBC Boilers, Turbines, Condensers, Steam & Heat rate, Subsystems of thermal power plants –

Fuel and ash handling, Draught system, Feed water treatment. Binary Cycles and Cogeneration

systems.

UNIT II DIESEL, GAS TURBINE AND COMBINED CYCLE POWER PLANTS 10

Otto, Diesel, Dual & Brayton Cycle - Analysis & Optimization. Components of Diesel and Gas

Turbine power plants. Combined Cycle Power Plants. Integrated Gasifier based Combined

Cycle systems.

UNIT III NUCLEAR POWER PLANTS 7

Basics of Nuclear Engineering, Layout and subsystems of Nuclear Power Plants, Working of

Nuclear Reactors : Boiling Water Reactor (BWR), Pressurized Water Reactor (PWR), CANada

DeuteriumUranium reactor (CANDU), Breeder, Gas Cooled and Liquid Metal Cooled Reactors.

Safety measures for Nuclear Power plants.

UNIT IV POWER FROM RENEWABLE ENERGY 10

Hydro Electric Power Plants – Classification, Typical Layout and associated components

including Turbines. Principle, Construction and working of Wind, Tidal, Solar Photo Voltaic

(SPV), Solar Thermal, Geo Thermal, Biogas and Fuel Cell power systems.

UNIT V ENERGY, ECONOMIC AND ENVIRONMENTAL ISSUES OF POWER PLAN

8

Power tariff types, Load distribution parameters, load curve, Comparison of site selection

criteria, relative merits & demerits, Capital & Operating Cost of different power plants.

Pollution control technologies including Waste Disposal Options for Coal and Nuclear Power

Plants.

TOTAL: 45 PERIODS

OUTCOMES:

• Upon completion of this course, the students can able to understand different types of

power plant, and its functions and their flow lines and issues related to them.

• Analyse and solve energy and economic related issues in power sectors.



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TEXT BOOK:

1. Nag. P.K., "Power Plant Engineering", Third Edition, Tata McGraw – Hill Publishing

Company Ltd., 2008.

REFERENCES:

1. El-Wakil. M.M., "Power Plant Technology", Tata McGraw – Hill Publishing Company

Ltd., 2010.

2. Black & Veatch, Springer, "Power Plant Engineering", 1996.

3. Thomas C. Elliott, Kao Chen and Robert C. Swanekamp, "Power Plant Engineering",

Second Edition, Standard Handbook of McGraw – Hill, 1998.

4. Godfrey Boyle, "Renewable energy", Open University, Oxford University Press in

association with the Open University, 2004.



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Subject Code: ME6701 Year/Semester: IV /07

Subject Name: Power Plant Engineering Subject Handler: Mr.D.Arunkumar

UNIT I COAL BASED THERMAL POWER PLANTS

Rankine cycle - improvisations, Layout of modern coal power plant, Super Critical Boilers, FBC Boilers,

Turbines, Condensers, Steam & Heat rate, Subsystems of thermal power plants – Fuel and ash handling,

Draught system, Feed water treatment. Binary Cycles and Cogeneration systems.

PART * A

Q.No. Questions

1.

Name the four major circuits in steam power plant. BTL1

• Coal - ash circuit

• Air - flue gas circuit

• Feed water - steam circuit

• Cooling water circuit

2

Describe the construction of air and flue gas circuit. BTL1

Air - flue gas circuit consists of forced draught fan, air-pre-heater, boiler, furnace, super heater,

economiser, dust collector, induced draught fan and chimney.

3

Brief about feed water and steam flow circuit in steam power. BTL1

The feed water- steam flow circuit consists of feed pump, economiser boiler drum super heater,

turbine and condenser.

4

Describe the construction of cooling water circuit and coal & ash circuit in steam power

plant. BTL1

The cooling water circuit consists of a pump, condenser and cooling tower. The coal and ash

circuit consists of coal delivery, preparation of coal, handling of coal to the boiler furnace, ash

handling and ash storage.

5

Highlight the purpose of the reservoir. BTL1

The main purpose of reservoir is to store water received from catchments areas during the rainy

seasons and supply the same during the dry season.

6

Name the two types of coal handling. BTL2

• Out plant handling

• In-plant handling

7

Brief about out-plant handling. BTL1

Out plant handling includes the handling of coalmine to the thermal power plant. These

handlings are outside the plant in the following ways.

• Transportation by sea (or) river

• Transportation by rail

• Transportation by road

• Transportation of coal by pipeline.

8

Define in plant handling of-coal. BTL1

In order to handle large quantity of coal inside the plant, some mechanical handling

systems are provided f6r smooth, easy and better controlled operation. The inplant coal handling

is divided, into following categories.



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• Coal unloading

• Coal preparation

• Coal transfer

• Coal storage

9

Why the preparation of coal is necessary? BTL1

The coal from coal mines cannot be directly fed into the furnace. Proper preparation of

coal should be done before feeding the coal to the furnace. In the coal preparation, the coal passes

through the different equipment’s like 1. Crushers 2. Sizers 3. Driers - Magnetic Separators.

10

Name the different types of coal transforming equipment. BTL2

Belt conveyors, Screw conveyors, Bucket elevators, Grab bucket elevators, Skip hoists, Flight

conveyors. The coal transfer starts by carrying of coal from-unloading point to the storage site.

11

What is the use of belt conveyors? BTL1

Belt conveyors are mostly used for transporting coal over long distance with large

quantity. An endless belt is made to run over a pair of end drums and pulleys and supported by

series of roller at regular intervals.

12

Write about screw conveyor and bucket conveyors. BTL1

In screw conveyor, an endless helicoid screw is fitted to the shaft. On one end of the shaft,

the driving mechanism is fitted, and the other end of the shaft is supported on a ball bearing.

While the screw is rotating, the coal is transferred` from one end to the other end.

Bucket conveyors are used as vertical lifts. The coal is loaded at the bottom and unloaded

at the top in the bucket conveyors.

13

Highlight the main purpose of chimney. (BLT)

The main purpose of chimney is to emit the flue gases at a considerable height to avoid

nuisance to the surrounding people.

14

Mention the different types of loads acting on the chimney. BTL1

There are two types of loads acting on the chimney namely.

• Its own weight which is considered to as a single vertical force acting through the

centroid, and

• The Wind pressure, which is considered as the horizontal force acting on the centroid of

vertical projected area.

15

Mention the advantages of induced draft cooling tower over forced draft cooling tower.

BTL1

• The outlet water comes in contact with the driest air and warmest water comes in contact

with most humid air.

• The re-circulation is seldom a problem.

• The first cost is low due to the reduction in pump power consumption.

17

Enumerate the important advantages of re-heating. BTL1

• Due to reheating, network done increases

• Heat supply increases

• Thermal efficiency increases

• Due to reheating, the turbine exit dryness fraction increases so moisture decreases - so

blade erosion becomes minimum - so life of the turbine will be increased.



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18

Name different methods of reheating. BTL1

• Gas Reheating

• Live - steam reheating

• Combined gas live steam reheater.

19

Define bleeding in steam power plant. BTL1

Assume 1 kg of steam is expanded in the turbine. Before complete amount of steam is

expanded, some amount of steam (m kg) is extracted. The extracting the steam in the turbine

before exhaust is called bleeding. This bled steam is used to heat the feed water.

20

Write about fluidized bed boilers. BTL1

When the high velocity gas is passed through a packed bed of finely divided solid

particles, the particles become suspended in the gas stream and the packed bed becomes a

fluidized bed. When the gas velocity is very high, the fluidized bed become turbulent and rapid

mixing of particles occurs. Ultimately, the, behaviour of mixture solid particles and gas become a

fluid. Burning of a fuel in such a state is known as Fluidized Bed Combustion. The boiler plant

using this fluidized bed combustion is known as fluidized bed boilers.

PART * B

1

Explain the process of Rankine Cycle. (13M) (APRIL 2008,2011) BTL2

Answer: Page 1.5 – R.PRAVEENA

The Rankine cycle is a thermodynamic cycle.

Like other thermodynamic cycle, the maximum efficiency of the Ranking cycle is given by calculating the maximum efficiency of the carnot cycle.

The ideal Rankine cycle consists of the following four processes, as shown in fig.

1-2: Isentropic compression in a pump.

2-3: Constant pressure heat addition in a boiler.

3-4: Isentropic expansion in a Turbine.

4-1: Constant pressure heat rejection in a condenser. (5M)

Construction:(5M) T-S Diagram:(3M)

2

Briefly Describe the working of a steam power plant followed by four circuits. (13M)

(DECEMBER 2015,2012,2011 APRIL 2011,2013) BTL2




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• Fuel - ash circuit (3M)

• Air - flue gas circuit (3M)

• Feed water - steam flow circuit (3M)

• Cooling water flow circuit (4M)



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3

Explain the working principle of supercritical boilers. (13M) (APRIL 2008,2011) BTL2


A forced circulation boiler was first introduced in 1925 by La Mont. The arrangement of

water circulation and different components.

The feed water from hot well is supplied to a storage and separating drum (boiler)

through the economizer. Most of the sensible heat is supplied to the feed water passing through

the economizer.

A pump circulates the water at a rate 8 to 10 times the mass of steam evaporated. This

water is circulated through the evaporator tubes and the part of the vapour is separated in the

separator drum. The large quantity of water circulated (10 times that of evaporation) prevents the

tubes from being overheated. (8M)

(5M)

4

Explain the fluidized bed combustion process with neat sketch. (13M) (APRIL 2012,2014)

BTL2

Answer: Page 1.6 – R. PRAVEENA

FLUIDIZED BED COMBUSTION (FBC)

Fluidized bed combustion has emerged as a viable alternative and has significant

advantages over conventional firing system and offers multiple benefits – compact boiler

design, fuel flexibility, higher combustion efficiency and reduced emission of noxious

pollutants such as SOx and NOx.

The fuels burnt in these boilers include coal, washery rejects, rice husk, bagasse & other

agricultural wastes. The fluidized bed boilers have a wide capacity range- 0.5 T/hr to over 100

T/hr. (8M)



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(5M)

5

Explain the various steps involved in coal handling. (13M) (APRIL 2011) BTL2


Coal delivery equipment is one of the major components of plant cost. The various steps

involved in coal handling are as follows:

1. Coal delivery.

2. Unloading

3. Preparation

4. Transfer

5. Outdoor storage

6. Covered storage

7. Inplant handling

8. Weighing and measuring

9. Feeding the coal into furnace. (3M)



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Explanation:(10M)

6

Briefly describe the classification of draught (13M) (DECEMBER 2012,2014) BTL2


• Draught is defined as the difference between absolute gas pressure at any point in a gas

flow passage and the ambient (same elevation) atmospheric pressure.

• Draught is achieved by small pressure difference which causes the flow of air or gas to

take place.

classification of draught



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Explanation:(13M)

PART * C

1

Write the types of pulverized coal firing system. Draw and Explain

(i) Unit system (or) Direct System

(ii) Bin (or) Central system

(iii) Semi direct firing system. (15M) (ARIL 2012) BTL2


• Hot air is passed through coal in the factor to dry the coal. The coal is then transferred to

the pulverizing mill where it is pulverized.

• Primary air is supplied to the mill, by the fan. The mixture of pulverized coal and primary

air then flows to burner where secondary air is added.

• The unit system is so called from the fact that each burner or a burner group and

pulverizer constitute a unit.



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Explanation each system with diagram:(15M)

2

Draw and Explain the working principle of

(a) Fluidized Bed Combustion

(b) Atmospheric bubbling bed combustor

(c) Circulating bed combustor and write the advantages of fluidized bed

combustion(15M) (DECEMBER 2014 ) BTL2

Answer: Page 1.31– R.PRAVEENA

As the fluidizing velocity is increased, smaller particles are entrained in the gas stream and

transported out of the bed. The bed surface, well-defined for a BFB combustor becomes more

diffuse and solids densities are reduced in the bed. A fluidized bed that is operated at velocities

in the range of 4 to 7 m/s is referred to as a circulated fluidized bed, or CFB. A schematic of a

typical CFB combustor is illustrated in figure.

Explanation each system with diagram:(15M)

3

Draw and explain the working principle of Economizer. (15M) (DECEMBER 2012) BTL2


• Economizers may be parallel or counter-flow types. When the gas flow and water flow are

in the same direction, it is called parallel flow economizer.

• In counter-flow, the gas flow and water flow are in opposite direction.

Construction:



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• An economizer used in modern high pressure boilers is shown by a line sketch.

• It consists of a series of vertical tubes. These tubes are hydraulically pressed into the top

and bottom headers. The bottom header is connected to feed pump. Top header is

connected to the water space of the boiler.

• It is provided with a safety valve which opens when water pressure exceeds a certain

limit. To keep the surface of the tubes clean from soot and ash deposits, scrapers are

provided in the tubes. These scrapers are slowly moved up and down to clean the surfaces

of the tubes.

• The action of adjacent pairs of scraper is in opposite direction. i.e., when one scraper

moves up, the other moves down. (5M)

(5M)

Fig. Economizer

Working

• The feed water is pumped to the bottom header and this water is carried to the top header

through a number of vertical tubes.

• Hot flue gases are allowed to pass over the external surface of the tubes. The feed water

which flows upward in the tubes is thus heated by the flue gases. This pre-heated water is

supplied to the boiler.

(5M)



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UNIT II DIESEL, GAS TURBINE AND COMBINED CYCLE POWER PLANTS

Otto, Diesel, Dual & Brayton Cycle - Analysis & Optimization. Components of Diesel and Gas Turbine

power plants. Combined Cycle Power Plants. Integrated Gasifier based Combined Cycle systems.

PART * A

Q.No. Questions

1.

Define open cycle gas turbine. BTL1

In the open cycle gas turbine, air is drawn into the compressor from atmosphere and is

compressed. The compressed air is heated by directly burning the fuel in the air at constant

pressure in the combustion chamber. Then the high pressure hot gases expand in the turbine and

mechanical power is developed.

2

Define closed cycle gas turbine. BTL1

The compressed air from the compressor is heated in a heat exchange (air heater) by some

external source of heat (coal or oil) at constant pressure. Then the high pressure hot gases expand

passing through the turbine and mechanical power is developed. The exhaust gas is then cooled

to its original temperature in a cooler before passing into the compressor again.

3

List few fuels for Gas turbine and why these fuels are used for gas turbine. BTL1

Natural gas, blast furnace gas, produce gas, coal gas and solid fuels distillate oils and

residual oils paraffins used in gas turbine and methane, ethane, propane, octane.

Important properties to be considered while selecting the fuel for gas turbine are as

follows:

i) Volatility ii) Combustion products, iii) Energy contents, iv) Lubricating properties, v)

Availability.

4

Write the major field of application of gas turbines. BTL1

The major fields of application of gas turbines are:

i) Aviation

ii) Power generation

iii) Oil and gas industry

iv) Marine propulsion.

5

Define Gas turbine plant and write the working medium of this gas turbine. BTL1

A gas turbine plant may be defined as one “in which the principal prime-mover is of the

turbine type and the working medium is a permanent gas.

6

What are the components of gas turbine plant? BTL1

A simple gas turbine plant consists of the following:

i) Turbine

ii) Compressor

iii) Combustor

iv) Auxiliaries.

A modified plant may have in addition and intercooler, a regenerator, a reheater etc.

7

What is the main difference between free piston engine plants and conventional gas turbine

plant? BTL1

Free-piston engine plants are the conventional gas turbine plants with the difference that



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the air compressor and combustion chamber are replaced by a free piston engine.

8

List the essential components of diesel power plants. BTL1

Essential components of a diesel power plant are:

(i) Engine

(ii) Air intake system

(iii) Exhaust system

(iv) Fuel system

(v) Cooling system

(vi) Lubrication system

(vii) Engine starting system

(viii) Governing system.

9

Mention the injection systems are used in diesel power plants. BTL1

Commonly used fuel injection system in a diesel power station:

(i) Common-rail injection system

(ii)Individual pump injection system

(iii) Distribution system.

10

List the various Liquid Cooling Systems. BTL1

In liquid cooling following methods are used for circulating the water around the cylinder

and cylinder head:

(i) Thermo-system cooling

(ii) Forced or pump cooling

11

What are the methods to improving the thermal efficiency in open cycle gas turbine plant?

BTL1

Methods for improvement of thermal efficiency of open cycle gas turbine plant are :

i) Inter cooling

ii) Reheating

iii) Regeneration

12

What is the significance of lubrication system in diesel engine power plant? BTL2

The lubrication system consists of oil pumps, oil tanks, filters, coolers and connecting

pipes. The purpose of the lubrication is to reduce the friction of moving parts and also pipes to

reduce the wear and tear of moving parts.

13

Name two combined power cycles. BTL1

(i) Combined cycle of gas turbine and steam power plant.

(ii) Combined cycle of gas turbine and diesel power plant.

14

Define turbo charging in combined gas turbine and diesel cycles. BTL1

In the combined cycle, the exhaust gas from the diesel engine is expanded in the turbine,

which is coupled with compressor which supplies pressurized air to the diesel engine. This

increases diesel engine output. This arrangement is known as turbo charging.

15

Define Reheat cycle. BTL1

If the dryness fraction of steam leaving the turbine is less than 0.88, then, corrosion and

erosion of turbine blades occur. To avoid this situation, reheat is used.

17 What are the various Lubricating systems are used in I.C Engines? BTL1

Various Lubrications systems use for I.C. engines are:



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(i) Wet sump lubrication system

(ii) Dry sump lubrication system

(iii) Mist lubrication system.

18

Write the function of Lubrication. BTL1

To reduce the wear and tear between the moving parts and thereby increasing the life of the

engine.

19 Define oil atomization. BTL1

Air blast fuel atomization compressed air at 70 bar used to atomize & inject fuel. For this Compressor and storage tank required which is expensive.

20 Define solid injection. BTL1

Fuel oil is forced to flow through spray nozzles at a pressure of above 100 bar.

PART * B

1

Explain the process of diesel power plant. (13M) (APRIL 2008,2013) BTL2


• The combustion process converts the fuel's chemical energy into heat energy, whether the

fuel is supplied by fuel injectors or a carburetor.

• Diesel power plant’s is in the range of 2 to 50 MW capacity. They are used as central

station for small or medium power supplies.

• They can be used as stand-by plants to hydro-electric power plants and steam power

plants for emergency services.

• They can be used as peak load plants in combinations with thermal or hydro-plants. (7M)

(6M)



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2

Explain the brayton cycle and its significance. (13M) (DECEMBER 2015) BTL2


• The Brayton cycle is a thermodynamic cycle named after George Brayton who describes

the workings of a constant-pressure heat engine.

• Two types of Brayton cycles are open to the atmosphere and using internal combustion

chamber or closed and using a heat exchanger. (5M)

Construction(4M) T-S Diagram:(4M)

3

Explain the Components of Diesel power plants. (13M) (APRIL 2008,2011) BTL2


Components Present in the Diesel Power Plant:

• Diesel engine

• Air filters

• Super chargers

• Engine starting system

• Fuel system

• Lubrication system.(8M)



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(5M)

4

Explain the combined cycle of gas turbine power plants. (13M) (DECEMBER 2014) BTL2


• A combined-cycle power plant uses both a gas and a steam turbine together to produce

up to 50 percent more electricity from the same fuel than a traditional simple-cycle

plant.

• The waste heat from the gas turbine is routed to the nearby steam turbine, which

generates extra power.(8M)



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(5M)

5

Explain the Integrated Gasifier based Combined Cycle systems (13M) (DECEMBER 2015)

BTL2


• An integrated gasification combined cycle (IGCC) is a technology that uses a high

pressure gasifier to turn coal and other carbon based fuels into pressurized gas synthesis

gas (syngas).

• It can then remove impurities from the syngas prior to the power generation cycle. (8M)



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(5M)

6

Explain the process of ideal and actual Otto cycle (13M) (DECEMBER 2012,2014) BTL2


• An Otto cycle is an idealized thermodynamic cycle that describes the functioning of a

typical spark ignition piston engine.

• The Otto cycle is a description of what happens to a mass of gas as it is subjected to

changes of pressure, temperature, volume, addition of heat, and removal of heat.

• An Otto cycle consists of four processes:

Process 1-2: Isentropic compression

Process 2-3: Constant Volume Heat Addition:

Process 3-4: Isentropic expansion

Process 4-1: Constant Volume Heat Rejection (5M)



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(8M)

PART * C

1

Explain the construction and working principle of Open cycle gas turbine power plant.

(15M) (ARIL 2012) BTL2


• In the open cycle gas turbine, air is drawn into the compressor from atmosphere and is

compressed.

• The compressed air is heated by directly burning the fuel in the air at constant pressure in

the combustion chamber.

• Then the high pressure hot gases expand in the turbine and mechanical power is

developed.

• Part of the power developed by the turbine (about 66%) is used for driving the

compressor. The remaining is available as useful output.

• The working fluid, air and fuel, must be replaced continuously as they are exhausted into

the atmosphere. Thus the entire flow comes from the atmosphere and is returned to the

atmosphere. (8M)



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(7M)

2

Explain the working of gas turbine cycle with reheater. (15M) (DECEMBER 2014 ) BTL2


• A reheater is basically a superheater that superheats steam exiting the high-pressure stage

of a turbine. The reheated steam is then sent to the low-pressure stage of the turbine.

• Reheating is applied in a gas turbine in such a way that it increases the turbine work

without increasing the compressor work or melting the turbine materials.

• When a gas turbine plant has a high pressure and low pressure turbine a reheater can be

applied successfully.

• Reheating can improve the efficiency up to 3 %.

• A reheater is generally is a combustor which reheat the flow between the high and low

pressure turbines (5M)

Construction (5M) T-S Diagram (5M)

3

Explain the working of gas turbine cycle with regenerator. (15M) (DECEMBER 2012)

BTL2


• Regenerative air standard gas turbine cycles shown in figure

• A regenerator (counter flow heat exchanger) through which the hot turbine exhaust gas

and comparatively cooler air coming from compressor flow in opposite directions.

• Under ideal conditions, no frictional pressure drop occurs in either fluid stream while

turbine exhaust gas gets cooled from 4 to 4’ while compressed air is heated from 2 to 2’.



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• Assuming regenerator effectiveness as 100% the temperature rise from 2 – 2’ and drop

from 4 to 4’ is shown on T-S diagram.(5M)

Construction (5M) T-S Diagram (5M)

UNIT III NUCLEAR POWER PLANTS

Boiling Water Reactor (BWR), Pressurized Water Reactor (PWR), CANada DeuteriumUranium reactor

(CANDU), Breeder, Gas Cooled and Liquid Metal Cooled Reactors. Safety measures for Nuclear Power

plants.

PART * A

Q.No. Questions

1.

Write short note on Isotopes. BTL1

Isotopes are atoms that have the same number of protons and electrons but different numbers of

neutrons and therefore have different physical properties.

2

Define Isobars. BTL1

Those atoms which have the same mass number but different atomic numbers are called

isobars. Obviously, these atoms belong to different chemical elements.

3

State Radioactivity. BTL1

The phenomenon of spontaneous emission of powerful radiations exhibited by heavy

element is called radioactivity. The radioactivity may be natural or artificial.

4

Write the types of Nuclear radiations. BTL2

The five types of nuclear radiations are:

• Gamma rays (or photons) : electromagnetic radiation.

• Neutrons: uncharged particles, mass approximately 1.

• Protons: + 1 charged particles, mass approximately 1.

• Alpha particles: helium nuclei, charge + 2, mass 4.

• Beta particles: electrons (charge – 1), positrons (charge + 1), mass very small.

5

What is meant by Fertile Materials? BTL1

It has been found that some materials are not fissionable by themselves but they can be

converted to the fissionable materials, these are known as fertile materials.

https://www.collinsdictionary.com/dictionary/english/proton

https://www.collinsdictionary.com/dictionary/english/electron

https://www.collinsdictionary.com/dictionary/english/physical

https://www.collinsdictionary.com/dictionary/english/property



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6

Define Fission. BTL1

Fission is the process that occurs when a neutron collides with the nucleus of certain of

heavy atoms, causing the original nucleus to split into two or more unequal fragments which

carry-off most of the energy of fission as kinetic energy. This process is accompanied by the

emission of neutrons and gamma rays.

7

Write about chain reaction. BTL1

A chain reaction is that process in which the number of neutrons keeps on multiplying

rapidly (in geometrical progression) during fission till whole the fissionable material is

disintegrated. The multiplication or reproduction factor (K) is given by:

. neutrons in any particular generation

No. of neutrons in the preceding generation

No ofK

If K > 1, chain reaction will continue and if K < 1, chain reaction cannot be maintained.

8

Define Nuclear fusion. BTL1

Nuclear fusion is the process of combining or fusing two lighter nuclei into a stable and

heavier nuclide. In this case large amount of energy is released because mass of the product

nucleus is less than the masses of the two nuclei which are fused.

9

Write the Essential components of a nuclear reactor. BTL2

Essential components of a nuclear reactor are:

• Reactor core

• Reflector

• Control mechanism

• Moderator

• Coolants

• Measuring instruments

• Shielding.

10

What are the main components of a nuclear power plant? BTL1

The main components of a nuclear power plant are:

• Nuclear reactor

• Heat exchanger (steam generator)

• Steam turbine

• Condenser

11

Mention some important reactors. BTL2

Some important reactors are :

• Pressurized water reactor (PWR)

• Boiling water reactor (BWR)

• Gas-cooled reactor

• Liquid metal-cooled reactor

• (v) Breeder reactor.

12 What are the factors considered for selecting the site for Nuclear power plant? BTL1



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Following factors should be considered while selecting the site for a nuclear power plant:

• Proximity to load centre

• Population distribution

• Land use

• Meteorology

• Geology

• Seismology

• Hydrology

13

List the methods of classification of Reactors. BTL1

• On the basis of neutron energy.

• On the basis of fuel used.

• On the basis of Moderate used.

• On the basis of coolant used.

14

List the advantages of nuclear power plant. BTL1

• It can be easily adopted where water and coal resources are not available.

• The Nuclear power plant requires very small quantity of fuel. Hence fuel transport cost is

less.

• Space requirement is very less compared to other power plant of equal capacity.

• It is not affected by adverse weather condition.

15

What are the desirable properties of a coolant? BTL1

• It should not absorb neutron

• Have high chemical and radiation stability

• Non-corrosive

• Have high boiling point

• Non-toxic

PART * B

1

Write a short note on:

(a) Fission Energy

(b) Chain Reaction

(c) Fusion Energy. (13M) BTL1 Answer: Page: 3.10 – R.PRAVEENA

• A nuclear power plant is similar to a conventional steam power plant except how that

energy is evolved.

• The heat is produced in the nuclear power plant by fission, whereas in steam and gas

turbine plants, the heat is produced by combustion in the furnace.

• The nuclear reactor acts as a furnace where nuclear energy is evolved by splitting or

fissioning of the nucleus of fissionable material like Uranium U-235.

• It is claimed that 1 kg U-235 can produce as much heat energy that can be produced by

burning 4500 tones of high grade coal or 1700 tons of oil.

Fission energy (5M)



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Figure: Nuclear fission

• Nuclear energy is divided from splitting (or) fissioning of the nucleus of

fissionable material like Uranium U-235.

• Uranium has several isotopes (Isotopes are atoms of the same element having

different atomic masses) such as U-234, U-235 and U-238.

• Of the several isotopes, U-235 is the most unstable isotope, which is easily

fissionable and hence used as fuel in an atomic reactor.

Chain reaction (4M)

• The neutrons released during fission are very fast and can be made to initiate the fission of

other nuclei of U-235, thus causing a chain reaction.

• When a large number of fission occurs, enormous amount of heat is generated, which is

used to produce steam.

Energy released in chain reaction, according to Einstein law is

E = mc2

Where E = Energy liberated (J)

m= Mass (kg)

c = Velocity of light (3 × 108 m/sec).

Fusion energy (4M)

• Energy is produced in the sun and stars by continuous fusion reactions in which four

nuclei of hydrogen fuse in a series of reactions involving other particles.

1 4 0

1 2 14 2H He e

Numbe

r

Fusion reaction Energy per

reaction

MeV Reactants Products

1 D + D T + p 4



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2 D + D He3 + n 3.2

3 T + D He4 + n 17.6

4 He3 + D He4 + p 18.3

2

Draw and explain the Sodium Graphite Reactor (SGR) (13M) BTL2 Answer: Page: 3.18 –

R.PRAVEENA

Sodium Graphite Reactor (SGR):

• The reactor shown in figure uses two liquid metal coolants.

• Liquid sodium (Na) serves as the primary coolant and an alloy of sodium potassium

(NaK) as the secondary coolant.(8M)

Diagram (5M)

3

Explain the construction and working principle of Pressurized Water Reactor (PWR)

(13M) BTL2 Answer: Page: 3.24 – R.PRAVEENA

Working principle:(7M)

• A nuclear power plant differs from a conventional steam power plant only in the steam

generating part. There is no change in the turbo-alternator and the condensing system.

• The nuclear fuel which is at present in commercial use is Uranium.

• Heat energy evolved by the fission reaction of one kg of U235 can produce as much energy

as can be produced by burning 4500 tons of high grade coal.



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(6M)

4

Explain the Nuclear power plant with neat sketch. (13M) BTL2 Answer: Page: 3.36 –

R.PRAVEENA

• Function of the moderator is to reduce the energy of neutrons evolved during fission in

order to maintain the chain reaction.

• The moderators which are commonly used are ordinary water and heavy water.(6M)

Diagram(7M)

5

Draw and explain construction and working principle of Boiling Water Reactor (BWR)

(13M) BTL2 Answer: Page: 3.42 – R.PRAVEENA

• These reactors are more economically to those nations which do not produce enriched



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uranium as the enrichment of uranium is very costly.

• In this type of reactors, the natural uranium (0.7% U235) is used as fuel and heavy water as

moderator.(7M)

Diagram (6M)

6

Draw and explain construction and working principle of CANDU type Reactor (13M) BTL2

Answer: Page: 3.51 – R.PRAVEENA

• This type of reactor was first designed and developed in Canada.

• The first heavy water reactor in Canada using heavy water as coolant and moderator of

200 MW capacity with 29.1% thermal efficiency was established at Douglas (Ontario

known as Douglas power station.

• The arrangement of the different components of CANDU type reactor is shown in figure

(7M)



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Diagram (6M)

PART * C

1

Draw and explain the working of Fast Breeder Reactor. (15M) BTL2 Answer: Page: 3.27 –

R.PRAVEENA

• In this reactor the core containing U235 in surrounded by a blanket (a layer of fertile

material placed outside the core) of fertile material U238.

• In this reactor no moderator is used. The fast moving neutrons liberated due to fission of

U235 are absorbed by U238 which gets converted into fissionable material Pu239 which is

capable of sustaining chain reaction.

• Thus this reactor is important because it breeds fissionable material from fertile material

U238 available in large quantities.

• Like sodium graphite nuclear reactor this reactor also uses two liquid metal coolant

circuits. Liquid sodium is used as primary coolant when circulated through the tubes of

intermediate heat exchange transfers its heat to secondary coolant sodium potassium alloy.

• The secondary coolant while flowing through the tubes of steam generator transfers its

heat to feed water.(7M)



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Diagram (8M)

2

What are the safety measures to be carried out in Nuclear Power Plant? (15M) BTL2


At nuclear power plants there are three main sources of radioactive contamination of air.

• Fission of nuclei of nuclear fuels.

• The second source is due to the effect of neutron fluxes on the heat carrier in the primary

cooling system and on the ambient air.

• Third source of air contamination is damage of shells of fuel elements. (5M)

The water purification plants must have efficiency of water purification and satisfy rigid

requirements as regards the volume of radioactive wastes disposed to burial.

• An atomic power plant should have an extensive ventilation system. The main purpose of

this ventilation system is to maintain the concentration of all radioactive impurities in the

air below the permissible concentrations.

• An exclusion zone of 1.6 km radius around the plant should be provided where no public

habitation is permitted.

• The safety system of the plant should be such as to enable safe shut down of the reactor

whenever required.(10M)

3

Explain briefly how the wastes are disposed from nuclear power plant.(15M) BTL2 Answer:

Page: 3.49 – R.PRAVEENA

Waste Disposal:



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• Waste disposal problem is common in every industry.

• Wastes from atomic energy installations are radioactive, create radioactive hazard and

require strong control to ensure that radioactivity is not released into the atmosphere to

avoid atmospheric pollution.

• The wastes produced in a nuclear power plant may be in the form of liquid, gas or solid

and each is treated in a different manner:

1. Liquid Waste (5M)

The disposal of liquid wastes is done in two ways:

i) Dilution

• The liquid wastes are diluted with large quantities of water and then released into the

ground.

• This method suffers from the drawback that there is a chance of contamination of

underground water if the dilution factor is not adequate.

ii) Concentration to small volumes and storage

• When the dilution of radioactive liquid wastes is not desirable due to amount or nature of

isotopes, the liquid wastes are concentrated to small volumes and stored in underground

tanks.

• The tanks should be of assured long term strength and leakage of liquid from the tanks

should not take place otherwise leakage or contents, from the tanks may lead to significant

underground water contamination.

2. Gaseous Waste (5M)

• Gaseous wastes can most easily result in atmospheric pollution.

• Gaseous wastes are generally diluted with air, passed through filters and then released to

atmosphere through large stacks (chimneys).

3. Solid Waste (5M)

• Solid wastes consist of scrap material or discorded objects contaminated with radioactive

matter.

• These wastes if combustible are burnt and the radioactive matter. These wastes if

concrete are drummed and shipped for burial.

• Non-combustible solid wastes are always buried deep in the ground.

UNIT IV POWER FROM RENEWABLE ENERGY

Hydro Electric Power Plants – Classification, Typical Layout and associated components including

Turbines. Principle, Construction and working of Wind, Tidal, Solar Photo Voltaic (SPV), Solar

Thermal, Geo Thermal, Biogas and Fuel Cell power systems.



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PART * A

Q.No. Questions

1.

What is the use of surge tank? (APRIL 2015) BTL1

The surge tank is used to provide better regulation of water pressure in the system. The

surge tank controls the water when the load on the turbine decreases and supplies water when the

load on the turbine increases. Thus, surge tank controls the pressure variations resulting from the

rapid changes in water flow in penstock and hence prevents water hammer.

2

What is the function of fore bay? BTL1

Fore bay is considered as naturally provided surge tank. It is temporary water

storage when the load on the plant is reduced and provides water for initial increment on

increasing load

3

Write a short note on penstock. (APRIL 2015) BTL1

The pipe between surge tank and prime mover is known as penstock. It is designed to

withstand high pressure. It is made up of reinforced concrete. In very cold areas, the penstock is

buried to prevent ice formation and to reduce the expansion joints.

4

What is the use of spill Ways? BTL1

Spillway is like a safety valve of the dam. It discharges major flood without damaging the

dam. It keeps the reservoir level below the maximum level allowed.

5

Write a short note on MHD – generator. (APRIL 2015) BTL1

‘Magneto Hydro Dynamic generator’ is a device which converts heat energy of a fuel

directly into electrical energy without a conventional electric generator.

6

What are the uses of air filter and superchargers in diesel engine power plant? BTL2

The purpose of air filter is to filter the air from dust and other suspended particles.

The purpose of super charger is to increase the pressure of the engine to increase power of the

engine.

7

What is the use of draft tube? (APRIL 2014) BTL1

The draft tube is used to regain the kinetic energy of water coming out of reaction turbine.

It enables the reaction turbine to be placed over tailrace level.

8

Define Tide. BTL1

The periodic rise and fall of the water level of sea which are carried by the action of sun

and moon on water of the earth is called the tide.

9 In which system the power is Intermittently generated? BTL1

In a single basin arrangement power can be generated only intermittently.

10

What are the consistencies ‘Solar farm’ and ‘Solar tower’? BTL1

The solar farm consists of a whole field covered with parabolic trough concentrators and a

‘solar tower’ consists of a central receiver on a tower and a whole field of tracking.

11 Define See beck effect. (APRIL 2016) BTL1

“If two dissimilar materials are joined to form a loop and the two junctions maintained at



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different temperatures, an e.m.f. will be set up around the loop”. This is called Seeback effect.

12 What is working principle of thermionic? BTL1

A thermionic converter works because of the phenomenon of ‘thermionic emission’.

13

What is Photo voltaic effect? BTL1

‘Photovoltaic effect’ is defined as the generation of an electromotive force as a result of

absorption of ionizing radiation.

14

List the four important solar systems. BTL1

1. Low temperature cycles using flat plat collector or solar pond

2. Power tower or central receiver system

3. Distributed collector system

4. Concentrating collectors for medium and high temperature cycle

15

List any four applications of solar collectors. (APRIL 2015) BTL1

1. Solar water heating

2. Solar space heating systems

3. Solar refrigeration

4. Industrial process heat systems

PART * B

1

Draw the Layout diagram of Hydro Power Plant and also explain the components and

working of Hydro power plant (13M) (APRIL 2011, 2012) BTL2 Answer: Page: 4.10 – R.PRAVEENA

(6M)

Components:

Hydroelectric power plant requires various components for generating electrical power. Some of

the major components in hydroelectric power plants are: Reservoirs, Dam, Trash Rack, Forebay,

Surge Tank, Penstock, Spillway, Prime Mover and Generator, Draft Tube.



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1. Hydropower or water power is power derived from the energy of falling water or fast

running water, which may be harnessed for useful purposes.

2. Since ancient times, hydropower from many kinds of watermills has been used as a

renewable energy source for irrigation and the operation of various mechanical devices,

such as gristmills, sawmills, textile mills, trip hammers, dock cranes, domestic lifts, and

ore mills.

3. A trompe, which produces compressed air from falling water, is sometimes used to power

other machinery at a distance (7M)

2

Write the advantages and disadvantages of Hydro-Electric Power plant. (13M) (APRIL

2008) BTL2 Answer: Page: 4.20 – R.PRAVEENA

Advantages:

1. Water is renewable source of energy. Water which is the operating fluid is neither

consumed nor converted into something else.

2. Water is the cheapest source of energy because it exists as a free gift of nature. The fuels

needed for the thermal, diesel and nuclear plants are exhaustible and expensive.

3. There is no ash disposal problem as in the case of thermal power plant.

4. Hydro-plant does not pose the problem of air pollution as in the case of thermal plant or

radiation hazards as in the case of nuclear plant.

5. Variable loads do not affect the efficiency in the case of a hydro-plant. (7M)

Disadvantages:

1. Hydro-plants are generally situated away from the load centers. Hence long transmission

lines are required for delivery of power. This increases the cost of transmission lines and

also transmission losses. But a thermal plant can be located near the load centre, thereby

the transmission cost and transmission losses are considerably reduced.

2. The power produced by hydro-plant depends upon the quantity of water which in turn is

dependent upon the rainfall. The dry year affects the hydro-power generation

considerably.

3. Initial cost of the plant is high.

4. Erection of hydro-plant (construction of dam etc.) usually takes long period of time. (6M)

3

Draw and Explain the construction and working principle of pumped storage plants. (13M)

(APRIL 2010,2012) BTL1


https://en.wikipedia.org/wiki/Power_(physics)

https://en.wikipedia.org/wiki/Energy

https://en.wikipedia.org/wiki/Watermill

https://en.wikipedia.org/wiki/Renewable_energy

https://en.wikipedia.org/wiki/Irrigation

https://en.wikipedia.org/wiki/Gristmill

https://en.wikipedia.org/wiki/Sawmill

https://en.wikipedia.org/wiki/Textile

https://en.wikipedia.org/wiki/Trip_hammer

https://en.wikipedia.org/wiki/Crane_(machine)

https://en.wikipedia.org/wiki/Elevator

https://en.wikipedia.org/wiki/Ore

https://en.wikipedia.org/wiki/Trompe



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(6M)

1. Pumped storage plants are employed at the places where the quantity of water available

for power generation is inadequate. Here the water passing through the turbines is store in

‘tail race pond’.

2. During low load periods this water is pumped back to the head reservoir using the extra

energy available. This water can be again used for generating power during peak load

periods. Pumping of water may be done seasonally or daily depending upon the

conditions of the site and the nature of the load on the plant. (7M)

4

Explain the construction and working principle of Solar power plant (13M) BTL2 Answer:


Solar electric systems use solar cells to convert the Sun's radiant energy into electricity.

This is done using a principle known as the photovoltaic effect. Since a solar cell only generates

about 1-2 Watts of power, it is necessary to combine them into solar power panels in order to

generate more power.

The electrons are captured in the form of an electric current - in other words, electricity.

A solar thermal plant generates heat and electricity by concentrating the sun's energy.

That in turn builds steam that helps to feed a turbine and generator to produce electricity. (7M)



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(6M)

5

Write the applications and advantages, disadvantages of solar power plant (13M) BTL2


Advantages

1. Sun is essentially an infinite source of energy. Therefore solar energy is a very large

inexhaustible and renewable source of energy and is freely available all over the world.

2. It is environmentally very clean and is hence pollution-free.

3. It is a dependable energy source without new requirements of a highly technical and

specialized nature for its wide spread utilization.

4. It is the best alternative for the rapid depletion of fossil fuels. (4M)

Disadvantages

1. It is available in a dilute and is at low potential. The intensity of solar energy on a sunny

day in India is about 1.1 kW/square meter area. Hence very large collecting areas are

required.

2. Also the dilute and diffused nature of the solar energy needs large land area for the power

plant for instance, about 30 square kilometers area is required for a solar power station to

replace a nuclear plant on a 1 square kilometer site. Hence capital cost is more for the

solar plant.

3. Solar energy is not available at night or during cloudy or rainy days. (4M)

Applications of Solar Energy:

Applications of solar energy enjoying most success today are:

1. Solar engines for pumping.



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2. Solar water heaters.

3. Solar cookers.

4. Solar driers.

5. Solar furnaces.

6. Photo-voltaic conversion (solar cells)

7. Solar power generation. (5M)

PART * C

1

Draw and Explain two basic design of Ocean Thermal Energy Conversion (OTEC) (15M)

BTL2


1. In the evaporator the pressure is maintained at a value (0.0317 bar) slightly lower than the

saturation pressure of warm surface water at 27C (0.0356 bar).

2. Hence, when the surface water enters the evaporator, it gets ‘superheated’. This super-

heated water undergoes “volume boiling” causing the water to partially flash to steam.

(8M)

(7M)

2

Explain the construction and working principle of Tidal power plants. (15M) BTL2 Answer:


1. Tide or wave is periodic rise and fall of water level of the sea.

2. Tides occur due to the attraction of sea water by the moon.

3. Tides contain large amount of potential energy which is used for power generation.

4. When the water is above the mean sea level, it is called flood tide. When the water level is

below the mean level it is called ebb tide.

5. Working of different tidal power plants Single basin-One-way cycle. This is the simplest

form of tidal power plant. In this system, a basin is allowed to get filled during flood tide

and during the ebb tide. The water flows from the basin to the sea passing through the

turbine and generates power (8M)



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(7M)

3

State and explain the kinds of Geothermal Sources. (15M) BTL2


Hydrothermal systems (3M)

1. Hydrothermal systems are those in which water is heated by contact with the hot rock, as

explained above.

2. Hydrothermal systems are in turn subdivided into 1) Vapor-dominated and 2) Liquid-

dominated systems.

Vapor-dominated systems (3M)

1. In these systems the water is vaporized into steam that reaches the surface in relatively dry

Condition at about 205C and rarely above 8 bar.

2. This steam is the most suitable for use in turboelectric power plants with the least cost. It

does, however, suffer problems similar to those encountered by all geothermal systems,

namely, the presence of corrosive gases and erosive material and environmental problems.

Liquid-dominated systems (3M)

1. In these systems the hot water circulating and trapped underground is at a temperature

range of 174 to 315C.

2. When tapped by wells drilled in the right places and to the right depths the water flows

either naturally to the surface or is pumped up to it. The drop in pressure, usually to 8 bar

or less, causes it to partially flash to a two-phase mixture of low quality, i.e., liquid-

dominated.

3. It contains relatively large concentration of dissolved solids ranging between 3000 to

25,000 ppm and sometimes higher.

Geopressured systems (3M)



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1. Geopressured systems are sources of water, or brine, that has been heated in a manner

similar to hydrothermal water, except that geopressured water is trapped in much deeper

underground acquifers, at depths between 2400 to 9100 m.

2. This water is thought to be at the relatively low temperature of about 160C and is under

very high pressure, from the overlying formations above, of more than 1000 bars.

Petrothermal systems (3M)

1. Magma lying relatively close to the earth’s surface heats overlying rock as previously

explained.

2. When no underground water exists, there is simply hot, dry rock (HDR).

3. The known temperatures of HDR vary between 150 to 290C. This energy, called petro

thermal energy, represents by far the largest resource base of the United States. Other

estimates put the ratio of steam: hot water: HDR at 1: 10: 1000.

UNIT V ENERGY, ECONOMIC AND ENVIRONMENTAL ISSUES OF POWER PLANTS

Power tariff types, Load distribution parameters, load curve, Comparison of site selection criteria,

relative merits & demerits, Capital & Operating Cost of different power plants. Pollution control

technologies including Waste Disposal Options for Coal and Nuclear Power Plants.

PART * A

Q.No Questions

1.

Define demand factor. BTL1

1. Demand factor is defined as the ratio of maximum demand to connected load.

2. Connected load is the sum of ratings in kW of equipment installed in the consumer's

premises.

3. Maximum demand is the maximum load, which a consumer uses at any time.

2

Define load curve. BTL1

Load curve is a graphical representation between load in kW and time in hours. It. shows

variati6n of load at the power station. The area under the load curve -represents the energy

generated in a particular period.

3

What includes fixed cost? BTL1

Fixed cost includes the following cost.

1. Cost of land 2. Cost of building

3. Cost of equipment 4. Cost of installati6n

5. Interest 6. Depreciation cost

7. Insurance 8. Management cost

4

What includes operating cost? BTL3

Operating cost includes the following cost.

1. Cost of fuel 2. Cost of operating labour,

3. Cost of maintenance labours and materials.

5

What are the components of solar energy? BTL1

1. Collector

2. Storage unit



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6

What is concentration ratio? BTL1

Concentration ratio is defined as the ratio between the aperture area and the receiver absorber area

of the collector.

7

List the various types of solar energy collectors. BTL1

1. Stationary collectors (or) Non- concentrating

(a) Flat plate collectors

(b) Compound parabolic collectors

(c) Evaculated tube collectors

2. Sun tracking concentrating collector

(a) single axis tracking

(b) Two-axis tracking

8

List the four important solar systems. BTL1

1. Low temperature cycles using flat plat collector or solar pond

2. Power tower or central receiver system

3. Distributed collector system

4. Concentrating collectors for medium and high temperature cycle

9

List any four applications of solar collectors. BTL1

1. Solar water heating

2. Solar space heating systems

3. Solar refrigeration

4. Industrial process heat systems

10

List the classification of OTEC based on location. BTL1

1. Land based plant

2. Shelf based plant

3. Floating plant

11

Define power tariff. BTL1

The amount of money frame by the supplier for the supply of electrical energy to various types of

consumers in known as an electricity tariff. In other words, the tariff is the methods of charging a

consumer for consuming electric power. The tariff covers the total cost of producing and

supplying electric energy plus a reasonable cost.

12

List the various components of wind energy system. BTL1

1. Rotor

2. Gearbox

3. Enclosure

4. Tail vane

13

What are the Types of Electricity Tariff? BTL1

1. Flat Demand Rate tariff

2. Straight-line Meter rate tariff

3. Block meter Rate tariff

4. Two-part tariff

5. Power factor tariff

6. Seasonal rate tariff

7. Peak load tariff



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8. Three-part tariff

14

Define Load Factor.BTL1

Load factor is defined as the ratio of the average load over a given period to the maximum

demand (peak load) occurring in that period. In other words, the load factor is the ratio of energy

consumed in a given period of the times of hours to the peak load which has occurred during that

particular period.

15

List the various types of turbines used in tidal power station. BTL1

1. Build turbine

2. Rim turbine

3.Tubular turbines

PART * B

1

Explain the various types of electricity tariff in detail. (13M) (APRIL 2011, 2012) BTL2


The amount of money frame by the supplier for the supply of electrical energy to various types

of consumers in known as an electricity tariff. In other words, the tariff is the methods of

charging a consumer for consuming electric power. The tariff covers the total cost of producing

and supplying electric energy plus a reasonable cost. (1M)

Simple tariff. In this type of tariff, a fixed rate is applied for each unit of the energy consumed. ...

• Flat rate tariff. (2M)

• Block rate tariff. (2M)

• Two part tariff. (2M)

• Maximum demand tariff. (2M)

• Power factor tariff. (2M)

• Three part tariff. (2M)

2

Explain the factors affecting power tariff. (13M) (APRIL 2008) BTL2


Factors Affecting the Electricity Tariffs

• Types of Load – The load is mainly classified into three types, i.e., domestic,

commercial, or industrial. The industrial consumers use more energy for a longer time

than domestic consumers, and hence the tariff for the industrial consumers is more than

the domestic consumers. The tariff of the electric energy varies according to their

requirement. (3M)

• Maximum demand – The cost of the electrical energy supplied by a generating station

depends on the installed capacity of the plant and kWh generated. Increased in maximum

capacity increased the installed capacity of the generating station. (2M)

• The time at which load is required – The time at which the maximum load required is

also essential for the electricity tariff. If the maximum demand coincides with the

maximum demand of the consumer, then the additional plant is required. And if the

maximum demand of the consumers occurs during off-peak hours, the load factor is

improved, and no extra plant capacity is needed. Thus, the overall cost per kWh generated

is reduced. (2M)



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• The power factor of the load – The power factor plays a major role in the plant

economics. The low power factor increases the load current which increases the losses in

the system. Thus, the regulation becomes poor. For improving the power factor, the power

factor correction equipment is installed at the generating station. Thus, the cost of the

generation increases. (3M)

• The amount of energy used – The cost of electrical energy is reduced by using large

amounts of energy for longer periods. (3M)

3

Explain about load distribution parameter. (13M) (APRIL 2010,2012) BTL1


The load duration curve is defined as the curve between the load and time in which the ordinates

representing the load, plotted in the order of decreasing magnitude, i.e., with the greatest load at

the left, lesser loads towards the rights and the lowest loads at the time extreme right. The load

duration curve is shown in the figure below.

(7M)

Procedure for Plotting the Load Duration Curve

1. From the data available from the load curve determines the maximum load and the

duration for which it occurs.

2. Now take the next load and the total time during which this and the previous load occurs.

3. Plots the loads against the time during which it occurs.

The load duration curves can be drawn for any duration of time, for example, a day or a month or

a year. The whole duration is taken as 100%. (6M)

4

Explain the various factors need to consider for selection of site for various power plants.

(13M) (APRIL 2010,2012) BTL1


https://circuitglobe.com/power-factor.html



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(7M)

Site selection process

1. Site selection involves measuring the needs of a new project against the merits of potential

locations.

2. The site selection, or facility location, decision is triggered when organisations seek to

locate, relocate or expand their operations.

3. The process involves the identification of alternative potentially viable locations, analysis

thereof, followed by evaluation and ranking of the sites.

4. Part of the business activities of the project team is to search for and select the optimal

location.

5. A four-phase approach is usually followed for site selection, including screening, site

work, negotiations and finalisation, as shown in Figure 1.

6. The screening phase will include a fatal flaw analysis to reduce the list of candidate sites

to only those that are viable.

7. Site work and negotiations will be necessary to obtain the information that will be used in

the selection and acquisition stage. (6M)

5

Explain the various types of pollutants in power stations. (13M) (APRIL 2010,2012) BTL1


Besides this, pollutants such as lead and hydrocarbons are contributed by automobiles.

The air pollution in a large measure is caused by the thermal power plants burning conventional



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fuels (coal, oil or gas).

The combustible elements of the fuel are converted to gaseous products and noncombustible

elements to ash.

Thus the emission can be classified as follow:

1. Gaseous emission

2. Particulate emission

3. Solid waste emission

4. Thermal pollution (or waste heat) (4M)

Gaseous Emission and Its Control:

The various gaseous pollutants are:

1. Sulphur dioxide

2. Hydrogen sulphide

3. Oxides of nitrogen

4. Carbon monoxide etc. (3M)

Particulate Emission and Its Control:

The particulate emission, in power plants using fossil fuels, is easiest to control.

Particulate matter can be either dust (particles having a diameter of 1 micron) which do not settle

down or particles with a diameter of more than 10 microns which settle down to the ground.

The particulate emission can be classified as follows:

1. Smoke: It composes of stable suspension of particles that have a diameter of less

than 10 microns and are visible only in the aggregate.

2. Fumes: These are very small particles resulting from chemical reactions and are

normally composed of metals and metallic oxides.

3. Fly-ash: These are ash particles of diameters of 100 microns or less. (6M)

PART * C

1

Explain the construction and working principle of MHD. (15M) BTL2


The planned application of the MHD concept for utility scale electric power generation uses

MHD as a topping cycle combined with a steam bottoming cycle, as shown in figure.

The MHD generation also known as magneto hydrodynamic power generation is a direct

energy conversion system which converts the heat energy directly into electrical energy, without

any intermediate mechanical energy conversion, as opposed to the case in all other power

generating plants.

Therefore, in this process, substantial fuel economy can be achieved due to the elimination of the

link process of producing mechanical energy and then again converting it to electrical energy.

(7M)



5/QB+Keys/Ver1.0

1- 45

(8M)

2

Explain the Thermo electric conversion system. (15M) BTL2


A typical couple operating with hot and cold junction temperatures of 600C and 200C could be

designed to give about 0.1 V and 2 A i.e., about 0.5 W, so that a 1 kW device could require about

5000 couples in series.

A thermoelectric generator also called a Seebeck generator is a solid state device that converts

heat flux (temperature differences) directly into electrical energy through a phenomenon called

the Seebeck effect.

Thermoelectric generators are solid-state heat engines made of pairs of p-type and n-type

elements.

The p-type elements are made of semiconductor materials doped such that the charge carriers are

positive (holes) and Seebeck coefficient is positive.

The n-type elements are made of semiconductor material doped such that the charge carriers are

negative (electrons) and the Seebeck coefficient is negative. (9M)

Figure: Thermoelectric generator (6M)

ME6701 POWER PLANT ENGINEERING L T P C 3 0 0 3 …Draught system, Feed water treatment. Binary...

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