CME 392 – POWER GENERATION EQUIPMENT DESIGN

2 MARKS

UNIT 1: INTRODUCTION

1. What are the types of power plants?

1. Thermal Power Plant
2. Diesel Power Plant
3. Nuclear Power Plant
4. Hydel Power Plant
5. Steam Power Plant
6. Gas Power Plant
7. Wind Power Plant
8. Geo Thermal
9. Bio – Gas
10. M.H.D. Power Plant
2. What are the flow circuits of a thermal Power Plant?
1. Coal and ash circuits.
2. Air and Gas
3. Feed water and steam
4. Cooling and water circuits
3. What are the Merits (Advantages) of Thermal Power Plant?
1. The unit capacity of thermal power plant is more. The cost of unit decreases with the increase in
unit capacity
2. Life of the plant is more (25-30 years) as compared to diesel plant (2-5 years)
3. Repair and maintenance cost is low when compared with diesel plant
4. Initial cost of the plant is less than nuclear plants
5. Suitable for varying load conditions.
4. What are the Demerits of thermal power plants?
1. Thermal plant are less efficient than diesel plants
2. Starting up the plant and brining into service takes more time
3. Cooling water required is more
4. Space required is more.
5. Explain Reheat cycle?
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. In the reheat cycle, the expansion of steam takes place in
one (or) more-turbines. Steam is expanded in the HP turbine first, and then it is reheated. The reheated steam is
again expanded in. the LP turbine.
6. What are the important advantages of Re-heating? (Nov/Dec 2005)
 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.

7. Explain the term Regeneration & advantages of Regeneration cycle?

  Regeneration means heating the feed water by steam taken from the turbine. The steam is exhausted
(bled) from the turbine at several locations before exhaust and is supplied to regenerator
(feed water heater) to heat the feed water.
Advantages of Regeneration cycle
 Heat supplied to boiler becomes reduced
 Thermal efficiency is increased since the average temperature of heat addition to the cycle is increased.
 Due to bleeding in the turbine, erosion of turbine due to moisture is reduced.

8. What are binary cycles? Give examples.(April-May-18)

 A binary vapor cycle is defined in thermodynamics as a power cycle that is a combination of

two cycles, one in a high temperature region and the other in a lower temperature region.
 The binary cycle is a process designed to overcome the imperfections of water as a working
fluid. The cycle uses two fluids in an attempt to approach an ideal working fluid
Example : Water-Mercury cycle.

9. Define steam rate and heat rate.(Nov-Dec’16)

Steam rate:
 It is defined as the rate of steam flow(Kg/hr) required for producing unit shaft output(1 KW).
 Therefore Steam Rate = 3600/Wnet (Kg/KWh)
Heat Rate:
 It is the rate of heat input(Q1) required for producing unit work output(1 KW).
 Heat Rate = (3600/Wnet)Q1(KJ/KWh)

10. What are the applications of gas turbine power plants?(April-May-18)

 Gas turbine power plants are used to supply peak loads in steam or hydro-plants.
 They are used as standby plants for hydro-electric power plants.
 Gas turbines are used in jet, aircraft and ships.
11. What are the applications of Diesel engine power plant? (April-May-17)
 They are quite suitable for mobile power generation.
 Widely used in transportation systems consisting of railroads, ships, automobiles and
aeroplanes.
 They can be used as standby power plants.
 Utilised during emergency period.
12. What are the Element of Hydel Power Plant?
 Water reservoir,
 Dam,
 Spillway,
 Pressure tunnel,
 Penstock,
 Surge tank,
 Water turbine,
 Draft tube,
 Tail race,
 Step-up transformer,
 Power house.
 13. Write the Advantages of Hydro-electric power plants?
 Water is a renewable source of energy. Water which is the operating fluid, is neither consumed nor
converted into something else,
 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.
 There is no ash disposal problem as in the case of thermal power plant.
14. Define Governing Mechanism?
 When the load on the turbine changes, the speed may also change. (i.e., without load the speed increases
and with over load, the speed decreases). Hence, the speed of the runner must be maintained constant to
have a constant speed of generator. This is done by controlling the quantity of water flowing on the
runner according to the load variations. This speed regulation is known as governing and it is usually
done automatically by a governor.
15. What is the function of governors in steam turbine? (AU.(MECH)DEC’08)
The governors regulate the supply of steam to the turbine to maintain constant speed of the turbine as far
as possible under varying load conditions.
16. What is meant by compounding of steam turbines? (AU.Nov’10)
Compounding is a method of absorbing the jet velocity in stages when the steam flows over moving
blades.
17. Explain the need of compounding in steam turbines. (AU (MECH) Apr’03 & Apr’08)
 In the simple impulse turbine, the expansion of stream from the boiler pressure to condenser
pressure takes place in a single stage turbine. The velocity of steam at the exit of turbine is very
high. So, there is a considerable loss of kinetic energy.
 Also, the speed of the rotor is very high .There are several methods of reducing this speed to a
lower value. Compounding is a method of absorbing the jet velocity in stages when the steam
flows over moving blades.
18. What are the different methods of governing steam turbines?
• Throttle governing
• Nozzle Governing
• By pass governing
• Combination of throttle and nozzle governing or throttle and by pass governing.
19. Enumerate the energy losses in steam turbines.
 Losses in regulating valves
 Losses due to steam friction
 Losses due to Mechanical friction
 Losses due to leakage
 Residual velocity losses
 Carry over losses
 Losses due to wetness of steam
 Losses due to radiation.
20. List the Vapour power cycles or Steam Cycles.
In this case, the working fluid exists in the vapour phase during one part of the cycle and in the liquid phase
during another part.
Vapour power cycles can be categorized as
a. Carnot cycle
b. Rankine cycle
c. Reheat cycle
d. Regenerative cycle
 e. Binary vapour cycle

21. What is thermodynamic cycle?

A Thermodynamic cycle is a series of thermodynamic processes transferring heat and work, while
varying pressure, temperature, and other state variables, eventually returning a system to its initial state.

22. List the various thermodynamic processes:

i. Adiabatic process- a process with no heat transfer into or out of the system
ii. Isochoric process- a process with no change in volume, in such case the system does no work
iii. Isobaric process- a process with no change in pressure
iv. Isothermal process- a process with no change in temperature

23. Under whatcircumstance will you recommend Diesel power plants? (AU.DEC’14)
Diesel power plants are mainly recommended where the fuel prices or reliability of supply favor oil
over coal where the water supply is limited and relatively small loads.

24. What are the components present in the Diesel electric power plants?
i. Engine
ii. Air intake system
iii. Engine starting system
iv. Fuel system
v. Exhaust system
vi. Cooling system
vii. Lubricating system

25. What are the methods by which thermal efficiency of a gas turbine power plant be improved?

1. Intercooling 2.Reheating 3.Regenerator 4.Combination of intercooling reheating and regenerator.

26. What is the function of draft tube?

1. It allows the turbine to be set above tail. Water level is without loss of head for doing inspection and
maintenance.
2. It regains the major portion of the kinetic energy delivered from the runner by the diffuse action.

27. What are the components of tidal power plants?

1. The dam or dyke
2. Sluice ways
3. The power house.

28. What are the different methods of producing electricity with tides?
1. Single basin arrangement
a) Single ebb-cycle system
b) Single tide-cycle system
c) Double cycle system
2. Double basic arrangement

29. What is a solar cell?

A solar cell is a device which directly converts the energy of light into electrical energy through the
 process of photovoltaic effect.
30. What is bio gas? Give the advantages.
Biogas is a type of gas that is formed by the biological breakdown of organic matter in an oxygen deficient
environment. It is counted as an ecofriendly biofuel. Biogas contains
60% methane and carbon dioxide. It can be employed for generating electricity and also as automotive fuel.
Biogas can be used as a substitute for compressed natural gas (CNG).
Advantages
o Provides a non-polluting and renewable source of energy.
o Efficient way of energy conversion (saves fuel wood).
o Leads to improvement in the environment, and sanitation and hygiene.
o Provides a source for decentralized power generation.
o Leads to employment generation in the rural areas.
o Household wastes and bio-wastes can be disposed of usefully and in a healthy manner.
31. Site selection criteria for hydroelectric power plant?
1. Availability of water 2. Water storage
2. Water head 3. Accessibility of site
4. Distance from the load centre 5. Type of the land of the site
32. Site selection criteria for thermal power plant?
1. Transportation network 2. Geology and soil type
3. Topography 4. Water resources 5.Population centre 6.Area size
33. Site selection criteria for nuclear power plant?
1. Availability of water 2. Disposal of Waste 3. Away from populated area
4. Nearest to the load centre 5. Other Factors – Accessibility to the road and rail are general
considerations.
34. List the various types of solar energy collectors.
1. Stationary collectors (or) Non- concentrating
(a) Flate plate collectors
(b) Compound parabolic collectors
(c) Evaculated tube collectors
2. Sun tracking concentrating collector
(a) single axis tracking
(b) Two-axis tracking
35. List any four applications of solar collectors.
 Solar water heating
 Solar space heating systems
 Solar refrigeration
 Industrial process heat systems
36. List the advantages and disadvantages of solar Energy.
 Solar energy is free from pollution
 They collect solar energy optically and transfer it to a single receiver, thus
minimizing thermal-energy transport requirements
 They typically achieve concentration ratios of 300 to 1500 and so are highly
efficient both in collecting energy and converting it to electricity
 The plant requires little maintenance or help after setup
 It is economical

Disadvantages
 Available in day time only
 Need storage facilities
  It needs a backup power plant
37. List the various components of wind energy system.
1. Rotor 2.Gearbox 3.Enclosure 4.Tailvane
38. What are the two basic designs of turbines?
1. Vertical axis (or) Egg beater style 2.Horizontal
axis (propeller style) machines
39. Write down the various types of wind power plants.
1. Remote 2.Hybrid 3.Grid connected
40. List any four advantages and disadvantages of wind turbine.
1. Inexhaustible fuel source 2.No pollution
3. Excellent supplement to other renewable source 4. Its free
Disadvantages
1. Low energy production 2.Expensive maintenance
42. What are the various ways of creating tidal energy?
1.Tidal Barrages 2.Tidal fences 3.Tidal turbines
43. What are the components of tidal power station?
1. Barrage 2.Turbines 3.Sluices 4.Embankments
44. What is fuel cell?
A fuel cell is an energy conversion device that reacts a fuel and oxygen to produce electricity. The
most common fuel is hydrogen. Produces electricity, water, and heat by the combination of
hydrogen and oxygen.
H2 + 1/2O2 H2O + Electrical Energy + Heat Energy
45. Write the advantages of fuel cell?

Water is the only discharge (pure H2)

High efficiency

Low weight and volume

Portable

No hazardous emissions
46. List the major components of gas turbine.
a.Compressor
b.Combustion chamber and
c.Turbine
47. List the types of gas turbine power plants.
a.Open cycle gas turbine power plant
b.Closed cycle gas turbine power plant
 UNIT – II COMBUSTION SYSTEM

1. Types of Fuels:
Fuels can be generally classified on the basis of two factors:
On the basis of their fuels state:
 Solid Fuels
 Liquid Fuels
 Gaseous Fuels
On the basis of their occurrence:
 Natural Fuels
 Artificial Fuels
2. What are fossil fuels?
Fossil fuels are the dead and decayed remains of plants and animals subjected to decades of pressure
and temperature under the earth’s crust. Primarily fossil fuels are hydrocarbons. They are convenient
and effective. They provide the calorific value required to fulfil our needs. Even though they are
available in plenty right now, they are a non-renewable source of energy. The burning of fossil fuels is
responsible for a large section of the world’s pollution index.
Types of fossil fuels:
 Coal
 Oil
 Natural Gas
3. Classification of Fuels.

4. Types of Coals:

5. List some of the solid fuels.

Wood, Coal, Oil Shale, Tanbark, Bagasse, Straw, Charcoal, Briquettes
6. List some of the Liquid fuels.
Petroleum, Oils from distillation of petroleum, Coal Tar, Shale-Oil, Alcohols, etc.
7. List some of the Gaseous Fuels
Natural Gas, Coal gas, Producer Gas, Water Gas, Hydrogen, Acetylene, Blast Furnace Gas, Oil Gas
8. What is a solid fuel? List its advantages and disadvantages.
Fuels which are found in their solid state at room temperature are generally referred to as Solid Fuels.
Coal was another one of the influential fuels known to man as it leads the way for the industrial
revolution, from firing furnaces to running steam engines.
Advantages:
 Easier transportation and storage.
 Low production cost.
 Moderate ignition temperature.
Disadvantages:
 Large portion of energy is wasted.
 Cost of handling is high and controlling is also hard.
 Ash content is high & burn with clinker formation.
9. What is a Liquid fuel? List its advantages and disadvantages.
Most liquid fuels are derived from the fossilized remains of dead plants and animals by exposure to
heat and pressure in the Earth’s crust. The fumes of the liquid fuel are flammable instead of the liquid.
Advantages:
 Higher calorific value per unit mass.
 Burn without ash, clinkers, etc.
 Controlling the combustion is easier.
 Transportation easier through pipes and stored indefinitely without loss.
 Loss of energy is comparatively lower.
 Require less furnace space for combustion.
Disadvantages:
 Cost of liquid fuel is much higher compared to solid fuel.
 Storage methods are costlier.
 Greater risk of fire hazards.
 Special burning equipment required for more efficient combustion.
10. What is a Gaseous fuel? List its advantages and disadvantages.
Gaseous fuels occur in nature, besides being manufactured from solid and liquid fuels. Most gaseous
fuels are composed of hydrocarbons, carbon monoxide, hydrogen or a mixture of them all.
Advantages:
 Transportation through pipes is easy.
 Sparking combustion is really easy.
 They have a higher heat content.
 Clean after use.
 Do Not require any special burner technology.
Disadvantages:
 Large storage tanks required.
 As they are highly inflammable, the chance for fire hazards are extremely high and strict safety
measures need to be followed.
11. Define Calorific value or Heating value.
Calorific value, sometimes called heating value or heat of combustion, is a standard that measures
the total energy content produced in the form of heat when a substance is combusted completely
with air or oxygen.
The amount of heat energy produced on complete combustion of 1 kg of a fuel is called its calorific
value. The calorific value of a fuel is expressed in a unit called kilojoule per kg (kJ/kg).
12. Define Combustion.
The process in which a substance undergoes a chemical reaction in the presence of air (oxygen) to
produce heat and light is called combustion.
Combustion is a rapid chemical reaction between fuel and oxygen. When combustible elements of
fuel combine with O2, heat energy comes out. During combustion combustible elements like Carbon,
Sulfur, Hydrogen etc combine with oxygen and produce respective oxides.
13. What is Complete Combustion?
Complete combustion is the process in which a fuel reacts with oxygen to produce Carbon dioxide and
water, where a large volume of air is required for complete combustion to take place.
Combustion is known as an exothermic process that releases energy in the forms of heat and light.
When a fuel undergoes complete combustion, it releases the maximum energy from the fuel which is
being reacted.
C+O2 = CO2
14. What is meant by incomplete combustion?
Incomplete combustion is called a process in which a reaction occurs between oxygen and fuel, but
the products are Carbon monoxide and water.
Incomplete combustion occurs when combustion occurs in an insufficient supply of oxygen.
Incomplete combustion can also produce pure carbon soot, which is messy and can build up in
chimneys.
C+O2 = 2CO.
15. Differentiate complete and incomplete combustion.
S. No. Complete combustion Incomplete combustion
The combustion reaction that takes place in the The combustion reaction takes place in
1 presence of a sufficient or abundant amount of the presence of an insufficient amount of
oxygen is called a combustion reaction. oxygen.
In this type of combustion, the flame is of blue In this type of combustion, flame is of
2
colour. yellow colour.
3 It will produce no smoke It will produce soot
In this reaction, carbon dioxide is the primary In this reaction, carbon monoxide is the
4
product formed primary product formed
Example: Burning of wood that causes air
5 Example: Combustion of LPG
pollution

16. What is a pulverizer and why it is used?

A pulverizer or grinder is a Mechanical device for grinding many different types of materials.
Pulverize mill is used to pulverize the coal for combustion in the steam generating furnaces of
fossil fuel power plants.
Pulverizers (coal pulverizer) are used to pulverize pieces of coal into fine particles (100μm)
before placing into a boiler, to ensure efficient combustion. Pulverizers have three functions,
pulverization, drying and classification.
17. What is pulverization?
Pulverization is the process of converting coal into fine particles (Powdered form) to increase
the surface exposure, the coal is pulverised. This enables rapid combustion.
18. List the types of pulverizing mills.
The pulverised coal is produced by grinding the raw coal in pulverizing mills. There are three
types of pulverizing mills namely 1. Ball mill, 2. Hammer mill and 3. Ball and Race mill
19. What is ESP? State its use.
 An electrostatic precipitator (ESP) is a filtration device which is used to remove fine
particles such as dust and smoke from a flowing gas using the force of an induced
electrostatic charge minimally impeding the flow of gases through the unit.
 Electrostatic precipitators (ESP) collect dust in the flue gas produced by boiler.
20. What is stoker? Classify it.
Stoker is a feeding device which feeds solid fuels into the furnace in medium and large size power
plants.
Types:
(i) Overfeed stoker, and
1. Travelling grate stoker 2. Chain grate stoker 3. Spreader stoker
(ii) Underfeed stoker
 1. Single retort stoker 2. Multi retort stoker
21. What are two common methods used for burning coal.
1. Stoker firing 2. Pulverised fuel firing.
22. Why the preparation of coal is necessary?
The coal from coal nines 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 equipments like 1. Crushers 2.Sizers 3.Driers and Magnetic Separators.
23. What are the types of Pulverised fuel firing system?
There are two methods of pulverised fuel firing system.
 Unit or direct system,
 Bin or central system.
24. List the Advantages & Disadvantages of pulverized coal firing.
Advantages:
 It increases the efficiency of the boiler.
 It makes possible the use of wide variety of coal.
 It reduces time of raising temperature of steam.
 Combustion of pulverized coal can readily be adapted to automatic control.
 This system works successfully with or in combination with the gas and oil.
 Large amount of heat release is possible in this system compared to stoke firing
system.
 The banking losses are low compared to stoke firing system.
Disadvantages:
 Additional cost and complication of equipment.
 40% of the ash passes up through the chimney and spread itself upon the
surrounding.
 Special efforts are required to be made to precipitate most of the ash.
 The possibility of the explosion is more as coal burn like gas.
 The storage of powdered coal requires special attention and high protection from the
fire hazards.
25. What all are the types of burners used in thermal power plant?
The classification of burners is made on the rapidity of burning the coal and air in the
furnace
1. Long flame or U flame or Streamlined burner
2. Short flame or turbulent burner
3. Tangential burner
4. Cyclone burner
26. List the purpose of Burner Management System (BMS).
 To inhibit startup when unsafe conditions exist.
 To protect against the unsafe operating conditions and admission of improper quantities of fuel
to the furnace.
 To provide the operator with status information – operator assistance
 To initiate a safe operating condition or shutdown interlock if unsafe condition exists.
 BMS is a control system dedicated to boiler furnace safety and operator assistance”.

27. What is meant by FSSS?

FSSS (Furnace Safeguard Supervisory System)
 FSSS is designed by using many safety interlocks and complex logics which ensures the
 execution of a safe, orderly firing sequence during the Startup and Shutdown of Fuel Firing
Equipment (furnace).
 This FSSS system provides safety interlocks to protect against potential emergency situations
in the event of malfunctions of fuel firing equipment’s and associated air systems.
28. Classify the burners.

29. What is the difference between stocker firing and pulverised fuel firing?
The stocker firing method is used for firing solid coal whereas pulverised firing method is used for
firing pulverised coal.
30. What is the function of hot primary air?
Coal contains moisture. Hot air form the Primary Air Fans dry the coal in the pulverisers. This
makes the burning easy and efficient. This air also carries the dry coal powder from the
pulverisers to the burners in the boiler furnace. In the burners the coal powder is mixed with
the required amount of Combustion air and burned in the furnace.

31. Write about out-plant handling?

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.

32. Write about inplant handling of-coal?

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.

33. Why the preparation of coal is necessary?

The coal from coal nines 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 equipments like
 a. Crushers
b. Sizers
c. Driers and Magnetic Separators.

34. Name the different types of coal transforming equipments?

i. Belt conveyors
ii. Screw conveyors
iii. Bucket elevators
iv. Grab bucket elevators
v. Skip hoists
vi. Flight conveyors.
The coal transfer starts by carrying of coal from-unloading point to the storage site.

35. Write about screw conveyor and bucket conveyors?

In screw conveyor, an endless helicoid screw is fitted to the 9haft. 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.
36. Describe the steps to be followed in in-plant coal handling of coal.
(i) Coal delivery
(ii) Unloading
(iii) Preparation
(iv) Transfer
(v) Outdoor storage
(vi) Covered storage
(vii) In plant handling
(viii) Weighing and measuring
(ix) Feeding the coal into furnace

37. Define draught, what is the use of draught in thermal power plants?
Draught is defined as a small pressure difference required between the fuel bed (furnace) and
outside air to maintain constant flow of air and to discharge the gases through chimney to the
atmosphere. Draught can be obtained by chimney, fan, steam jet (or) -air jet (or) combination of
these.
The uses are To supply required quantity of air to the furnace for combustion of fuel., To draw the
combustion products through the system. To remove burnt products from the system

38. Write about classification of draught?

Draught is classified as
i. Natural draught
ii. Artificial draught .
The artificial draught is further classified as
1. Balanced draught
2. Induced draught
3. Forced draught

39. Define the term Natural draught and what are the advantages of natural draught system?
The tall chimney creates the natural draught by the temperature difference between hot gases in
the chimney and cold atmospheric air outside the chimney.

40. Write about artificial draught?

In modem power plants, the draught should be flexible to meet the fluctuating loads and it should
be independent of atmospheric conditions. To achieve this, the aid of draft fans becomes must and
 by employing the draft fans, the height of the chimney would be reduced.

41. Write about forced draught system? (NOV/DEC 2014)

In this system, the blower (forced draft fan) is located at the base of the boiler near the grate. Air
is forced to the furnace by forced fan and the flue gases are forced to chimney through economiser
and air preheater.

42. What are the advantages and disadvantages of forced draught system (NOV/DEC
2014) Advantages:
 Since the fan handles cold air, the fan size and the power required are less.
 No need of water cooled bearings because the air being handled is cold air,
 Pressure throughout the system is above atmospheric pressure so the air leakage into the
furnace is reduced.
Disadvantages:
 Recirculation due to high air-entry and low air-exit velocities inside the furnace. Thus
atmospheric air is induced to flow through the furnace to aid the combustion of fuel. The flue
gases drawn by the fan passes through chimney, to the atmosphere.

a. Why the balanced draught system is preferred than other system?

In the induced draught system, when the furnace is opened for firing, the cold air enters the
furnace and dilate the combustion. In the forced draught system, when the furnace is opened
for firing, the high pressure air will try to blow out suddenly and furnace may stop. Hence the
furnace cannot be opened for firing (q) inspection in both, systems. Balanced draught, which is
a combination of induced and forced draught, is used to overcome the above stated difficulties.

b. List the factors to be considered while choosing a site for steam power station:
i. Supply of fuel
2.Availability of water
3.Transportation facilities
4.Cost and type of land
5.Nearness to load centres
6.Distance from populated area

c. State important advantages of high-pressure boilers? (Nov/Dec 2012)

The amount of scale formation is less, since the velocity of water through pipes are more.
All parts of the system are heated uniformly, so there is no danger of overheating.

d. What is supercritical boiler? Give two advantages. (MAY/JUN 2013)

A supercritical steam generator is a type of boiler that operates at supercritical pressure,
frequently used in the production of electric power.
In contrast to a subcritical boiler, a supercritical steam generator operates at pressures above the
critical pressure 22 MPa in which bubbles can form. Instead, liquid water immediately becomes
steam. Water passes below the critical point as it does work in a high pressure turbine and enters
the generator's condenser, resulting in slightly less fuel use and therefore less greenhouse gas
production.
 Advantages:
o Higher unit cycle efficiency (40 - 42%)
o Lower heat rate and electricity generation cost is lower
o Lower water losses because no continuous blow down
o Reduced auxiliary power consumption

e. What is the purpose of deaeration?

The purpose of deaeration are:
 To remove oxygen,carbon dioxide and other non-condensable gases from feed water.
 To heat the incoming makeup water and return condensate to an optimum temperature
 Minimizing solubility of undesirable gases
 Providing the highest temperature water for injection to the boiler.

f. What are the types of deaerators?

i. Tary- ype Deaerating heaters
ii. Spray-Type Deaerating heaters

g. What is meant by cooling Towers?

It is a tower or building like device in which atmospheric air circulates in direct or indirect contact
with warmer water and water is thereby cooled. Cooling towers may either use the evaporation of
water to remove process heat and cool the working fluid.
h. List the types of cooling towers:

i. Evaporative or wet cooling tower

2.Nonevaporative or dry cooling tower
(a) Air cooled condensers
(b) Air cooled
exchangers
i. List the types of cooling functions to condense the steam:
i. Once-through wet cooling
2.Recirculating wet cooling
3.Dry cooling

j. Write short notes on cogeneration.

Cogeneration or combined heat and power (CHP) is the use of a heat engine or power station to
generate electricity and useful heat at the same time. Cogeneration is a thermodynamically
efficient use of fuel. In separate production of electricity, some energy must be discarded as
waste heat, but in cogeneration this thermal energy is put to use.

k. List the thermal power plant in Tamilnadu.

 Alathiur(2*18MW), Tamilnadu, Madras cements
 Ennore(2*60MW,3*110MW) Tamilnadu Electricity Board
  Neyveli(6*50MW,2*100MW) Tamilnadu Neyveli lignite corp Ltd.
l. Define super heater:
A Super heater is a device used to convert saturated steam into a dry steam used for power
generation or processes steam which has been super heated is known as superheated steam.
m. List the types of super heaters:
i. Radiant super heater- absorb heat by radiation

ii. Convention super heater-absorb heat via a fluid

iii. Separately fixed super heaters- it is totally separated from the boiler

n. What is crusher and its crushing method?

A crusher is a machine designed to reduce large solid chunks of raw materials into smaller
chunks. Crushers are commonly classified by the degree to which they fragment the starting
material.
Crushing methods:
i. Impact
2.Shear
3.Attrition
4.Compression

UNIT 2: DIESEL, GAS TURBINE AND COMBINED CYCLE POWER PLANTS

48. List the advantages of gas turbine power plant.

a. Low capital cost
b. High reliability
c. Flexibility in operation
d. Capability to quick start
e. High efficiency e.t.c.
49. List the major components of gas turbine.
a.Compressor
b. Combustion chamber and
c. Turbine
50. List the types of gas turbine power plants.
a.Open cycle gas turbine power plant
b. Closed cycle gas turbine power plant
51. List the disadvantages of gas turbine power plant.
a.No load and Partial load efficiency is low
2.High sensitive to component efficiency
3. The efficiency depends on ambient pressure and ambient temperature
 4. High air rate is required to limit the maximum inlet air temperature. Hence exhaust losses
are high
5. Air and gas filter is required to prevent dust into the combustion chambers.
5. Define regenerator efficiency.
The regenerator efficiency is defined as: =Actual temperature rise of air/ Maximum
temperature rise possible
6. List the factors which affect the performance of gas turbine power plants.
1. Part load efficiency
2. Fuel consumption
3. Air mass flow rate
4. Thermal efficiency
5. Regeneration
7. List the methods adopted for circulating the water in a cooling system.
1. Thermosiphon cooling
2. Forced cooling by pump
3. Thermostat cooling
4. Pressurised water cooling
5. Evaporative cooling

8. What are the important functions of a lubricating system?

1. Lubricating
2. Cooling
3. Cleaning
4. Sealing
5. Noise absorption
9. List the various types of lubricating system used in diesel engine.
1. Mist lubricating system
2. Wet sump lubrication system
3. Dry sump lubrication system

10. What are the starting methods of diesel engine?

1. By an auxiliary engine
2. By an electric motor
3. By compressed air
11. List any four advantages of diesel power plant.

1. It is easy to design and install 2. It is easily available in standard capacities

3. They can respond to load changes 4. They have less stand by losses
12. List any four disadvantages of diesel power plant.
1. High operating cost
2. High maintenance and lubrication cost
 3. Capacity is restricted
4. Noise pollution
12. List any four applications of diesel power plant.
1. Used as peak load plants
2. Suitable for mobile plants
3. Used as standby units
4. Used as emergency plant

13. List the various types of diesel plants.

Based on number of strokes:
(a) Two stroke diesel engine (b) Four srtoke diesel engine
Based on orientation:
(a) Horizontal diesel engine (b) Vertical diesel engine
Based on number of cylinders:
(a) single cylinder (b) Multi cylinder
Based on aspiration
(a)naturally aspirated (b)supercharging or turbocharging.

14 .List the components of diesel power plant.

1. Diesel engine 2. Air intake system 3. Exhaust system 4. Fuel system
5. Cooling system 6. Lubricating system

15. List the reason why the cooling system is necessary for a diesel engine.
1. To avoid damages and overheating of piston
2. To avoid uneven expansion which results in craking in the piston and cylinder
3. To avoid pre-ignition and detonation or knocking
4. To avoid reduction in volumetric efficiency and power output of the engine
16. List the various functions of fuel injection system.
1. It filters the fuel
2. Monitor the correct quantity of fuel to be injected
3. Timing of the injection process
4. Regulates the fuel supply
5. Fine atomization of fuel oil
6. Distributes the fuel evenly to all cylinders in case of multi cylinder engine

17. List the classification of oil injection system.

(a) Common rail injection system (b) Individual pump injection system (c) Distributor system

18. What are the methods of cooling system used?

1. Air cooling 2. Liquid cooling (water is commonly used liquid)

19 .What are the working fluids in gas turbine?

1. Air
2.Helium
3.Argon
4.Carbon dioxide

20. List the various types of diesel plants.

Based on number of strokes:
(a) Two stroke diesel engine
(b) Four stroke diesel engine
Based on orientation:
(a) Horizontal diesel engine
(b) Vertical diesel engine
Based on number of cylinders:
 (a) single cylinder
(b) Multi cylinder
And other type like naturally aspirated, superheated etc.,

21. List the various functions of fuel injection system.

1. It filters the fuel

2. Monitor the correct quantity of fuel to be injected
3. Timing of the injection process
4. Regulates the fuel supply
5. Fine atomization of fuel oil
6. Distributes the automized fuel properly inside the combustion chamber
22. List the classification of oil injection system.
(a) Common rail injection system
(b) Individual pump injection system
(c) Distributor system
23. List the reason why the cooling system is necessary for a diesel engine.
 To avoid detemiation of lubricating oil
 To avoid damages and overheating of piston
 To avoid uneven expansion which results in craking
 To avoid pre-ignition and detonation or knocking
 To avoid reduction in volumetric efficiency and power output of the engine

24. What are the methods of cooling system used?

1. Air cooling
2. Water cooling
25. List the methods adopted for circulating the water in a cooling system.
1. Thermosiphon cooling
2. Forced cooling by pump
3. Thermostat cooling
4. Pressurised water cooling
5. Evaporative cooling
26. What are the important functions of a lubricating system?
1. Lubricating
2. Cooling
3. Cleaning
4. Sealing
5. Noise absorption
27. List the various types of lubricating system used in diesel engine.
1. Mist lubricating system
2. Wet sump lubrication system
3. Dry sump lubrication system
28. What are the starting methods of diesel engine?
1. By an auxiliary engine
2. By an electric motor
3. By compressed air
29. List any four advantages of diesel power plant.
1. It is easy to design and install
2. It is easily available in standard capacities
3. They can respond to load changes
4. They have less stand by losses
30. List any four disadvantages of diesel power plant.
1. High operating cost
2. High maintenance and lubrication cost
3.Capacity is restricted
4.Noise pollution
31. List any four applications of diesel power plant.
1. Used as peak load plants
2. Suitable for mobile plants
3. Used as standby units
4. Used as emergency plant

32. List the disadvantages of gas turbine power plant.

1. No load and Partial load efficiency is low
2. High sensitive to component efficiency
3. The efficiency depends on ambient pressure and ambient temperature
4. High air rate is required to limit the maximum inlet air temperature. Hence exhaust losses are high
5. Air and gas filter is required to prevent dust into the combustion chambers.
33. Define regenerator efficiency.
The regenerator efficiency is defined as the ratio between actual temperature rise of air to maximum
temperature rise possible.

34. List the factors which affect the performance of gas turbine power plants.
1. Part load efficiency 2. Fuel consumption 3. Air mass flow rate 4. Thermal efficiency 5.
Regeneration

35. What are the working fluids in gas turbine?

1. Air 2. Helium 3. Argon 4. Carbon dioxide

36. What is the function of draft tube? (MAY/JUN 2013)

The draft tube is a conduit which connects the runner exit to the tail race where the water is being
finally discharged from the turbine. The primary function of the draft tube is to reduce the velocity of
the discharged water to minimize the loss of kinetic energy at the outlet. This permits the turbine to be
set above the tail water without any appreciable drop of available head.

37. How solid injection is classified? (MAY/JUN 2013) Solid Injection Classification:
 Common Rail System
 Unit Injection System
  Individual Pump and Nozzle System
 Distributor System
38. What do you mean by regeneration in gas turbine power plant? (MAY/JUN 2013)
The hot exhaust gases from the turbine are passed through a heat exchanger, or regenerator, to
increase the temperature of the air leaving the compressor prior to combustion. This reduces the
amount of fuel needed to reach the desired turbine-inlet temperature. The increase in efficiency is,
however, tied to a large increase in initial cost and will be economical only for units that are run
almost continuously.
39. Write about types of turbines. (NOV/DEC 2013)
Major classifications are,
(1) Impulse turbine
(2)Reaction turbine
Subdivided into,

(a) Kaplan Turbine

(b)Propeller Turbine
(c)Francis Turbine
(d)Pelton Turbine
40. What type of cycle is used in gas turbine? (NOV/DEC 2013)
In an ideal gas turbine, gases undergo three thermodynamic processes: an isentropic compression, an
isobaric (constant pressure) combustion and an isentropic expansion. Together, these make up the Brayton
cycle.

o. What is hydraulic/ Pneumatic type ash handling system?

The hydraulic system carried the ash with the flow of water high velocity through a channel and
finally dumps into a sump. The hydraulic system is divided into a low velocity and high velocity
system.
The advantages of this system are that its clean, large ash handling capacity, considerable distance
can be traversed, absence of working parts in contact with ash. In pneumatic type ash handling is
the most popular method used in medium level power plants. It uses dense phase conveying
system for conveying ash is totally enclosed without any leakage. The system can convey
materials up to distance of around 200 -250 mts.

p. List the challenges of ash handling:

i. Indian coal contains high ash content generally which tends to be inconsistent.
ii. Design of the system has to adequately cover anticipated variations and be capable of
handling the worst scenario
iii. System has to be environmentally friendly
iv. System has to be energy efficient
 UNIT 3: NUCLEAR POWER PLANTS
1. What is meant by radioactivity?

It refers to the german name of Radio-Activitat. Radioactivity is the spontaneous

disintegration of atomic nuclei. The nucleus emits particles or electromagnetic rays during
this process.
2. What is the unit of Radioactivity?
1. Roentgen
2. RAD(Radiation Absorbed Dose)

3. RBE(Relative Biological Effectiveness)

4.REM(Roentgen Equivalent in Man)
5.Gray(GY)-100 rads 6.Sievert(SV)
3. What are the types of Radioactive decay?
1. Alpha decay
2.Beta decay
3. Gamma decay
4. Poistron emission(Beta positive decay)
5.Electron capture
4. Define-Decay timing.

The number of decay events – d N expected to occur in a small interval of time dt is proportional
to the number of atoms present. If N is the number of atoms, then the probability of decay(-d /N)
is proportional to dt.
5. What is Uranium enrichment?

In most types of reactor, a higher concentration of uranium is used to make fuel rod. This
produced by a process termed enrichment. The enriched uranium containing more than natural
0.7% U-235.
6. What are the two ways of uranium enrichment?
1. Gas centrifuge process
2. Gas diffusion
7. What is the purpose of reprocessing of nuclear waste?
The used fuel contains 96% uranium,1% plutonium and 3% radioactive wastes. Reprocessing
is used to separate the waste from the uranium and plutonium which can be recycled inti new
fuel. The reprocessing effectively reduces the volume of waste and limits the need to mine
new supplies of uranium, so that extending the time of resources.
8. Write about atomic number?
The nucleus contains protons and neutrons. The number of protons in a given atom is an
atomic number (Z). The atomic number for H is 1 and He -is 2.

9. Write about isotopes of an element?

 Some elements have the same number of protons in the nucleus but different number- of
neutrons. As a result, these elements have the same atomic number but different mass number. Such
type of elements which ' have the same atomic number – same number of protons - the -same
chemical properties but different mass numbers due to different number of neutrons, are known as I
the isotopes of an element.
10. What are the requirements to sustain fission process?
The bombarded neutrons must have sufficient energy to cause fission, The number of
neutrons produced must be able to create the rate of fission, The fission process must generate energy,
The fission process must be controlled
11. Define multiplication factor of a fission process.
Number of neutrons of any one generation
k= number of neutrons of immediately preceding generation.
12. Define fertile materials and breeding in reactors
235 232
There are materials like U and Th which are not fissile but can be converted into fissile
materials by the bombardment of neutrons. Such materials are known as fertile materials.
The process of converting more fertile material into fissile material in a reaction is known as
breeding.
13. What are the desirable properties of a good moderator? (MAY/JUN 2014)
It must be as light as possible It must slowdown the neutron as quick as possible, It must have
resistance to corrosion .It must have good machinability, It must have good conductivity and high
melting point
14. What are the desirable properties of a coolant?

It should not absorb neutron, Have high chemical and radiation stability, Non-corrosive, Have
high boiling point Non-toxic

15. What are the advantages using CO2 as coolant?

 Gases do not react chemically with the structural materials, Gas can attain any temperature for
a particular pressure
 They do not absorb neutron, The leakage of gas will not affect the reactivity, The gas coolant
provides best neutron economy
16. What are the advantages of breeder reactors?
It gives high power density than any other reactor, High breeding is possible, High burn-up of fuel is
achievable, The operation of the reactor is not limited by Xe poisoning
17. What are the demerits of breeder reactor?
Highly enriched fuel is required, Control is difficult and expensive, Safety must be provided against
melt down, Handling of sodium is a major problem
18. What are the advantages of Sodium in fast-breeder reactors?
Sodium has very low absorption cross-sectional area, It possess good heat transfer properties at high
temperature and low pressure, It does not react with any of the structural materials used in primary
circuits
19. What is the purpose of control rods?
The control rods are used to start the chain reaction, maintain the chain reaction at required level and
to shut down the reactor during emergency.

20. What is meant by Nuclear fission? (NOV/DEC 2013)

Uranium exists in different isotopes of U238, P34 and U235. Out of these, EP35 is most unstable.
When unstable heavy nucleus is bombarded with high-energy neutrons, it splits up roughly into two
equal
21. Define Nuclear Fission.
An atom’s nucleus can be split apart. When this is done a tremendous amount of energy is
released. The energy is both heat and light energy. This energy ,when let out slowly can be
harnessed to generate electricity.
22. Name the different components of nuclear reactor?
1. Nuclear fuel 2. Moderator 3. Control rods 4. Reflectors, 5. Reactor vessel 6. Biological
shielding 7. Coolant
23. State some advantages of Pressurized Water reactor?
 The pressurized water reactor is compact
 In this type, water is used as coolant, moderator and reflector water is cheap and available
in plenty)
 It requires less number of control rods.
24. What are the advantages of gas cooled reactor nuclear power plant?

1. Fuel processing is simple, 2. The use of C02 as coolant completely eliminates the
possibility of explosion in reactor. 3. No corrosion problem

25. Name the coolants commonly used for fast breeder reactors?
Liquid metal (Na (or) Na K), Helium (He), Carbon dioxide.

26. What is the- necessity of Automatic controls for feed water?

The electrical load on power plant varies in an irregular manner. The automatic control provided at
a steam power plant successfully meets over the variable load. The automatic control for feed water
is necessary sine the supply of feed water depends upon plant load.
27. What is the difference between fission and fusion? (Nov/Dec 2012) (MAY/JUN 2014)

S. Nuclear Fission Nuclear Fusion

NO

In nuclear physics and nuclear chemistry, In nuclear physics, nuclear chemistry

nuclear fission is a nuclear reaction in which the and astrophysics nuclear fusion is the
nucleus of an atom splits into smaller parts process by which two or more atomic
1 (lighter nuclei), often producing free neutrons nuclei join together, or "fuse", to form a
and photons (in the form of gamma rays). single heavier nucleus.

The two nuclei produced are most often of This is usually accompanied by
comparable size, typically with a mass ratio the release or absorption of large
2
around 3:2 for common fissile isotopes. quantities of energy.

28. List the four types of radiation associated with nuclear fission.
 Alpha radiation
 Beta radiation
 Gamma radiation
 Neutron radiation

29. Write few ways of Nuclear Power plant safety.

Radiation doses can be controlled through the following procedures:
 The handling of equipment via remote in the core of the reactor
 Physical shielding
 Limit on the time a worker spends in areas with significant radiation levels
 Monitoring of individual doses and of the working environment
 Safety mechanism of a Nuclear power reactor

30. What is LMFBR? Why liquid metal preferred in fast breeder reactor? (MAY/JUN 2013)
A liquid metal fast breeder reactor (LMFBR) is a nuclear reactor capable of producing
more fissile product than it takes in. Breeders exhibit remarkable fuel economy compared to light
water reactors.Liquid metal use in fast breeder reactors has long been considered for the
improvement of efficiency in their heat transfer systems. Work has been performed around the
world on corrosion of sodium- and potassium-cooled fast breeder reactors.
The metal coolants have much higher density than the water used in most reactor designs,
they remove much heat more rapidly and allow much higher power density. This makes them
attractive in situations where size and weight are at a premium, like on ships and submarines
31. What is Neutron life time?
The prompt neutron lifetime, is the average time between the emission of neutrons and either
their absorbtion in the system or their escape from the system. The term lifetime is used
because the emission of a neutron is often considered its birth, and the subsequent absorption is
considered its death.
32. What is Uranium-235 chain Reactor?
In a chain reaction, particles released by the splitting of the atom go off and strike other
uranium atoms splitting those. Those particles given off split still other atoms in a chain
reaction. If an least one neutron from U-235 fission strikes another nucleus and causes it to
fission, Then the chain reaction will continue.
33. What is four factor formula?

The four factor formula is used in nuclear engineering to determine the multiplication of a nuclear
chain reaction in an infinite medium. The formula is:
Reproduction Factor - The thermal utilization factor
The resonance escape probability - The fast fission factor
34. List the four types of radiation associated with nuclear fission.
1. Alpha radiation
2. Beta radiation
3. Gamma radiation
4. Neutron radiation
35. Define Alpha radiation.
This is basically the atomic nucleus of the element(He) consisting of two protons and two
neutrons. It is not very penetrative and the danger to man arises if an alpha emitting element, such
as plutonium, then the alpha radiation be very damaging.

36. Define Beta radiation.

Beta radiation consists of electrons or their positively charged counterparts. This can penetrate
the skin, but not very far.
37. Define Gamma radiation.

Gamma radiation is penetrative in a manner similar to X-rays and has similar physical
properties. It can be stopped only by thick shields of lead or concrete.
38. Define Neutron radiation.

Neutron radiation consists of the neutrons emitted during the fission process. Neutrons are also
very penetrative, but less so then gamma-radiation.
39. Define water as moderator.

Neutrons from fission have very high speeds and must slowed greatly by water moderation to
maintain the chain raction. The Uranium-235 is enriched to 2.5-3.5% to allow ordinary water to
be the moderator. Enough spontaneous events occur to initiate a chain reaction if the proper
moderation and fuel density is provided.
40. List the types of Nuclear reactors.

The reactors are classified based on the following: 1.Type of fuel used
2. Neutron flux spectrum
3. The coolant
41. List the various widespread power plant reactor types.

1. Pressurized water reactor(PWR) 2.Boling water reactor(BWR)

21. Pressurized Heavy water reactor(PHWR)

22. Liquid metal fast Breeder Reactors(LMFBR)
23. High temperature Gas cooled reactors(HTGCR)
42. What is pressurized water reactors(PWR)?

The PWR belongs to the lidht water type. The moderator and the coolant are both light water(H2O).
The cooling water circulates in two loops, which are fully separated

from one another. PWR keep water under pressure, so the water heats but does not boil even at
the high operating temperature.

43. What is boiling water reactor(BWR)?

In a boiling water reactor, Light water plays the role of moderator and coolant as
well. Part of the water boils away in the reactor pressure vessel, thus a mixture of water and
steam leaves the reactor core.
44. What is Molten Salt Reactor(MSR)?
A molten salt reactor is a type of nuclear reactor where the primary coolant is a
molten salt. Molten salt refers to a salt that is in the liquid phase that is normally a solid at
standard temperature ionic liquid, although technically molten salts are a class of ionic liquids.
45. Nuclear Power plant safety.

Radiation doses can be controlled through the following procedures: 1.The handling of
equipment via remote in the core of the reactor
2. Physical shielding
3. Limit on the time a worker spends in areas with significant radiation levels
4. Monitoring of individual doses and of the working environment
5. Safety mechanism of a Nuclear power reactor
46. List the Nuclear power plants in India.
1. Kaiga(3*22MWPHWR), Karnataka
2. Kakrapar(2*22MWPHWR), Gujarat
3. Kudankulam(2*100MWPWR), Tamilnadu
4. Madras(2*17MWPHWR), Tamilnadu
47. Define mean generation time.

It is the average time from a neutron emission to a capture results in fission. The mean
generation time is different from prompt neutron lifetime because the mean generation time
only includes neutron absorption that leads to fission reaction.

UNIT 4: POWER FROM RENEWABLE ENERGY

1. What are the components of solar energy?

Collector
Storage unit

4. What is concentration ratio?

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

3. List the various types of solar energy collectors. (NOV/DEC 2013)

52. Stationary collectors (or) Non- concentrating

(d) Flate plate collectors

(e) Compound parabolic collectors
(f) Evaculated tube collectors
53. Sun tracking concentrating collector
(c) single axis tracking

(d) Two-axis tracking

54. List any four applications of solar collectors.

a. Solar water heating
b. Solar space heating systems
c. Solar refrigeration
d. Industrial process heat systems

55. List the four important solar systems.

a. Low temperature cycles using flat plat collector or solar pond
b. Power tower or central receiver system
c. Distributed collector system
d. Concentrating collectors for medium and high temperature cycle

56. List the advantages of solar Energy.

a. Solar energy is free from pollution

b. They collect solar energy optically and transfer it to a single receiver, thus minimizing
thermal-energy transport requirements
c. They typically achieve concentration ratios of 300 to 1500 and so are highly efficient both
in collecting energy and converting it to electricity

d. The plant requires little maintenance or help after setup

e. It is economical

57. List any four disadvantages of solar energy.

 a. Avilable in day time only
b. Need storage facilities
c. It needs a backup power plant

58. List the various components of wind energy system.

1.Rotor 2.Gearbox 3.Enclosure 4.Tailvane

9. What are the two basic design of turbines?

1.Vertical axis (or) Egg beater style 2.Horizontal axis

(propeller style) machines

10. Write down the various types of wind power plants.

1.Remote 2.Hybrid 3.Grid connected

11. List any four advantages of wind turbine.
1.Inexhaustible fuel source 2.No pollution
3.Excellent supplement to other renewable source 4.Its free
12. List the disadvantages of wind power generation.
1.Low energy production 2.Expensive maintenance
13. What are the various ways of creating tidal energy?
1.Tidal Barrager 2.Tidal fences 3.Tidal turbines
List the various types of turbines used in tidal power
14.station.
1.Buld
turbine 2.Rim turbine 3.Tubular turbines
15.What are the components of tidal power station?
1.Barrage 2.Turbines 3.Sluices 4.Embankments

16. List four advantages of hydro electric power plant. (MAY/JUN 2013)
 It is a clean and safe source of energy
 They are self sustaining
 They create habitat for more types of fish
 They can act as a flood controller
 They are the most efficient energy source running from 90-95% efficiency

17. What is pondage and storage? (MAY/JUN 2014)

STORAGE
In a conventional hydropower plant, the water from the reservoir flows through the plant,
exits and is carried down stream. A pumped-storage plant has two reservoirs: Upper
reservoir - Like a conventional hydropower plant, a dam creates a reservoir. The water in
this reservoir flows through the hydropower plant to create electricity. Lower reservoir -
Water exiting the hydropower plant flows into a lower reservoir rather than re-entering the
river and flowing downstream.
PONDAGE
It usually refers to the comparably small water storage behind the weir of a run-of-the-river
hydroelectric power plant. Such a power plant has considerably less storage than the reservoirs of
large dams and conventional hydroelectric stations which can store water for long periods such as a
dry season or year. With pondage, water is usually stored during periods of low electricity demand
and days when the power plant is inactive, enabling its use as a peaking power plant in dry seasons
and a base load power plant during wet seasons.

18. What is water hammer? ((MAY/JUN 2014)

Water hammer ( fluid hammer) is a pressure surge or wave caused when a fluid in motion is
forced to stop or change direction suddenly (momentum change). A water hammer
commonly occurs when a valve closes suddenly at an end of a pipeline system, and a pressure
wave propagates in the pipe. It is also called hydraulic shock.
19.What is the source of geothermal energy? (NOV/DEC 2013)

Geothermal energy is clean and renewable source of energy that refers to heat found in
Earth’s core. The geothermal energy is basically a form of thermal energy that has its origin
in radioactive decay of various minerals inside the Earth's core.
20.What is fuel cell?
A fuel cell is an energy conversion device that reacts a fuel and oxygen to produce electricity.
The most common fuel is hydrogen. Produces electricity, water, and heat by the combination
of hydrogen and oxygen.
H2 + 1/2O2 H2O + Electrical Energy + Heat Energy 21.Classifications of fuel cell?
(d)
Temperature
(a)Low temperature (< 300oC) (b)High Temperature (> 300oC)
(e)
Electrolyte
(a)PEMFC (low Temperature, proton- conducting polymer) (b)PAFC (200oC ,phosphoric
acid in a matrix)
59. AFC (KOH, 80oC aqueous potassium hydroxide in a matrix) (d)MCFC (650oC, molten
carbonate salt in a ceramic matrix) (e)SOFC (> 900oC, oxide ion-conducting ceramic) (f)BFC
- Biological Fuel Cell (Sugar)
a. Write the functions of platinum catalyst.
(a) Dissociate the C-H bond.
(b) Facilitate the reaction of the resulting residue with some oxygen containing
species to form CO2
b. Write the advantages of fuel cell?

Water is the only discharge (pure H2)

High efficiency

Low weight and volume

Portable

No hazardous emissions

24. Write short notes on Biological fuel cell?

 Biological fuel cell converts the chemical energy of carbohydrates, such as sugars and
alcohol directly into electrical energy.
First time Rohrback et al. designed the biological fuel cell in which clostridium butyricum
was used as a biological material to generate hydrogen from glucose fermentation.

25. What are sources of Biogas?

Biogas can be produced by anaerobic digestion of organic matter. Potential raw mateerials
available on a large scale are cow dung, municipal waste and plants specially grown for this
purpose like water hyancith, algae, certain types of grasses.
26. Write the formula to calculate the hydraulic power produced by a hydroturbine:
The hydraulic power is given by the formula:
P=GpQH
Where P is the hydraulic energy in watts
G is acceleration due to gravity (9.81 M/s2)
P is water density
Q is the flow or discharge
H is the height of fall of water or head in meter.

27. List any four advantages of hydro power:

1.Water source is perennially available
2.Running cost is very low
3. Non-polluting
4. Power generation can be switched on and off in a very short period.

28. List any four disadvantages of hydropower:

1. High capital investment and low rate of return
2. Gestation period is very large
3. Power generation depends on availability of water
4. Transmission cost and losses are high

29. List the factors to be considered for the selection of site for hydro power plant:
1.Availability of water and water head
2.Accessibility of site
3.Water storage capacity
4.Distance from the load center
5.Type of land

30. List the classification of dams:

1. Based on their functions:
(a) storage dams
(b) Diversion dams
(c) Detention dams
2.Based on their shape:
(a) Trapezoidal dams
(b) Arch dams
3. Based on the materials of construction:
(a)Earth dams (b) Rock pieces dams
(c) Stone masonary dams (d) concrete dams
(e) RCC dams (f)Timber and Rubber dam
4. Based on hydraulic design:
(a) Overflow type dam
(b) Non-overflow type dam
5. Based on structural Design:
(a) Gravity dam
(b) Arch dam
(c) Buttresses dam
31. What is a surge tank?
A surge tank is a small reservoir in which the water level rises or falls to reduce
the pressure swings during opening and closing of inlet valve. The surge tank is
not required for run off plants and medium head plants.
32. What is a Draft tube?

The draft tube allows the turbine to be set above the tail race to facilitate inspection
and maintenance. It also regains the major portion of the kinetic energy at the runner
outlet by diffuser action. The draft tube can be a straight conical tube or an allow tube.
33. List the equipments present in a power house:
1. Hydraulic turbines
2. Electric generators
3. Governors
4. Gate valves and rehet valves
5. Water circulating pumps
6. Air duct
7. Switch board and instruments
8. Storage batteries and cranes
34. List the types of hydro power plants based on availability of head;
1. High head power plant(head>100m)
2. Medium head power plant(30m-100m)
3. Low head power plants(head<30m)
35. List the advantages of pumped storage power plants:
1. Increases the peak load capacity at low cost
2. High operating efficiency
3.Better load factor
4.Independence of steam flow conditions
36. List the advantages of impulse turbine:
1.Greater tolerance of sand and other particles in the water
2.Better access to working parts
3.No pressure seals around the shaft
4.Easier to fabricate and maintain
5.Better part-flow efficiency
37. List any four pumped storage hydro power plants in India:
1. Bihar, Maharastra, 150 MW
2. Kadamparai, Coimbatore, Tamilnadu, 400MW
3. Nagarjuna Sagar PH, Andhra Pradesh,810MW
4. Purulia pumped storage project, Avodhva hills,West Bengal, 900MW
5. Srisailam Left Bank PH, Andhra Pradesh,900 MW
6. Tehri Dam, Uttranchal, 1000 MW
38. What are the essential elements of hydro power plant?
1. Catchment area
2. Reservation
3. Dam
4. Surge tanks
5. Draft tubes
6. Power house
7. Switched for transmission of power
39. What is meant by catchment area and explain its function:

The whole area behind the dam is called the catchment area. The rain water in
the area will be drained into the dam through a dam or river.
40. Explain Reservoir:

A reservoir may be natural, like a lake on a mountain or artificially

built by erecting a dam across a river.
41. Define surge tank:

A Surge tank is a small reservoir in which the water level rises swings
during opening and closing of inlet valve.
42. What is power house?
A power house is a stable structure which houses the equipment in the power plant
43. What is meant by pumped storage power plant?
The pumped storage plants are used for load balancing. During peak load water is
used to work on turbines to produce electricity. Water after working in turbines is
stored in the tail race reservoir.
45. What is mini Hydro plants?
The mini power plants operate with 5m-20m head and produce about 1 MW to 5 MW of power.
46.What is micro hydro plants?
The micro power plants require a head less than 5m and produce 0.1 MW
to 1 MW.
47.Define turbines:
A turbine converts energy in the form of falling water into rotating shaft power.
The selection of best turbine for any particular site depends on the site characteristics.
48. What are the disadvantages of impulse turbine?
They are unsuitable for low-head sites because of their low specific speeds.
49.What is pelton turbine?
A pelton turbine consists of a set of specially spread buckets mounted on a
periphery of a circular disc. It is turned by jets of water which are discharged from
one or more nozzles.
50.What is meant by reaction turbines?
Francis turbine and propeller turbines are the reaction turbines. The
reaction turbines rotate faster than impulse turbine.
51.What is meant by propeller turbine?
The basic propeller turbine consists of a propeller. Inside it consist
of a continuation of the penstock tube.
52.What is meant by Kaplan turbine?
The pitch of the propeller blades together with wicket gate adjustment, enables
reasonable efficiency to be maintained under part flow conditions. Such turbines
are called as Kaplan turbines.
53.Define twin runners:
Two runners can be placed on the same shaft either side by side or on
opposite sides of the generator. This configuration is unusual and would only
be used if the number of jets per runner had maximized.
54.State the advantages of impulse turbine over reaction turbine:
Impulse turbine are usually cheaper then reaction turbine because there is no
need for a specialist pressure casing.
55.Explain impulse turbine in terms of heads?
 High head- pelton Turgo
Medium head- Multi jet pelton turgo
Low head- cross flow
56.Explain reaction turbine in terms of head:
High head- Francis
Medium head- Propeller
Low head- Kaplan

UNIT 5: ENERGY ECONOMIC AND ENVIRONMENTAL ISSUES OF POWERPLANTS

1. Define demand factor?

Demand factor is defined as the ratio of maximum demand to connected load.Connected load is the
sum of ratings in kW of equipment installed in the consumer's premises. Maximum demand is the
maximum load, which a consumer uses at any time.
2. Define load curve?
Load curve is a graphical representation between load in kW and time in hours. It. shows variation of
load at the power station. The area under the load curve -represents the energy generated in a
particular period.
3. Define load factor?
Load factor is defined as the ratio of average load to the peak load (or) maximum demand.

4. What includes fixed cost?

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

5. What includes operating cost?

Operating cost includes the following cost.
1.Cost of fuel
2. Cost of operating labour
3. Cost of maintenance labours and materials
 4. Cost of supplier like
Water for feeding boilers, for condenser and for general use.
Lubrication oil and, grease.Water treatment chemicals.
6. What is the need of depreciation cost?
Depreciation cost is the amount to be set aside per year from the income of the plant to meet
the depreciation caused by the age of service, wear and tear of the machinery and equipments.
Depreciation amount collected every year helps in replacing and repairing the equipment.
7. Write the types of pollution control methods adopted in thermal power plants?
1. Air pollution control
(a)Electrostatic precipitators (b)Low NOX burners
(c)Flue gas stack (d) Dry ash extraction
2. Water pollution control
(a)Coal/oil setting pits (b)Ash dykes & disposal systems
(c) Ash water recycling system (d)Effluent treatment plant
3. Thermal pollution control
4. Noise pollution control
11. What are the pollutants come out of the coal fired power plant?
Coal combustion releases nitrogen oxides, sulfur dioxide, particulate matter (PM), mercury, and
dozens of other substances known to be hazardous to human health

12. Write advantages and disadvantages of nuclear power plant?

Advantages
• Economic
 • Environmental
• Portability & Productivity

Disadvantages
• Waste storage
• Accidents
• National Security
• Ease of peaceful usage to weapons program

13. What is the purpose of electrostatic precipitator?

An electrostatic precipitator (ESP) is a filtration device that removes fine particles, like dust
and smoke, from a flowing gas using the force of an induced electrostatic charge minimally impeding
the flow of gases through the unit.
14. Write nuclear waste disposal methods.
(a)Utilizing underground facility (b)Injecting into deep aquifers (c)Deep bore holes (d) Rock melting

15. Flyash Disposal in Ash Ponds

Primarily, the flyash is disposed off using either dry or wet disposal scheme. In dry disposal, the
flyash is transported by truck, chute or conveyor at the site and disposed off by constructing a dry
embankment (dyke). In wet disposal, the flyash is transported as slurry through pipe and disposed off
in impoundment called "ash pond". Most of the power plants in India use wet disposal system
16. What are the pollutants from nuclear power plants?
Nuclear power plants do not emit carbon dioxide, sulfur dioxide, or nitrogen oxides as part of
the power generation process. However, fossil fuel emissions are associated with the uranium mining
and uranium enrichment process as well as the transport of the uranium fuel to and from the nuclear
plant.
17. What do you mean by spent fuel? How it is disposed?
Every 18 to 24 months, nuclear power plants must shut down to remove and replace the "spent"
uranium fuel. This spent fuel has released most of its energy as a result of the fission process and has
become radioactive waste.
Currently, the spent fuel is stored at the nuclear plants at which it is generated, either in steel-lined,
 concrete vaults filled with water or in above-ground steel or steel-reinforced concrete containers with
steel inner canisters.

18. What are the effects on aquatic life and water by nuclear wastes?
 Heavy metals and salts build up in the water used in all power plant systems, including
nuclear ones. These water pollutants, as well as the higher temperature of the water
discharged from the power plant, can negatively affect water quality and aquatic life. Nuclear
power plants sometimes discharge small amounts of tritium and other radioactive elements as
allowed by their individual wastewater permits.
 Waste generated from uranium mining operations and rainwater runoff can contaminate
groundwater and surface water resources with heavy metals and traces of radioactive
uranium.

19. Radioactive Waste Generation and disposal methods?

 Enrichment of uranium ore into fuel and the operation of nuclear power plants generate
wastes that contain low-levels of radioactivity. These wastes are shipped to a few specially
designed and licensed disposal sites.
 When a nuclear power plant is closed, some equipment and structural materials become
radioactive wastes. This type of radioactive waste is currently being stored at the closed plants
until an appropriate disposal site is opened.
 Management, packaging, transport, and disposal of waste are strictly regulated and carefully
controlled by the U.S. Nuclear Regulatory Commission and the U.S. Department of
Transportation.

20. Write the nuclear waste streams that may harm the environment?

1. Spent nuclear fuel at the reactor site (including fission products and plutonium waste)

2. Tailings and waste rock at uranium during reactor operation

3. Releases of large quantities of dangerous radioactive materials during accidents