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ME 1354 - POWER PLANT ENGINEERING

Unit – I

1. What are the main factors considered for power output of hydroelectric power plant

operating?

1. Head of water .

2. Specified speed and rotational speed of turbine.

3. Part load efficiency.

4. Disposition of turbine shaft.

2. What is the purpose of surge tank?

The surge tank is a temporary storage safety reservoir fitted to the penstock that is in

between dam and power house to keep the back pressure minimum by avoiding sudden

pressure in the penstock.

3. What is the purpose of air intake system in a diesel engine power plant?

• The filter removes the air borne solid particles causing wear of engine.

• Silence reduces high velocity air noise.

• Super charger increases the pressure of air supplied

4. What are the advantages of high pressure boiler in modern thermal power plant?

1. Efficiency of plant is increased up to about 40 to 42%

2. Tendency of scale formation is eliminated.

3. It has less number or complete elimination of drums.

5. What is super critical boiler? List down its merits.

1. Heat transfer rate is considerably high.

2. It is possible to maintain more stable pressure level.

3. It is possible to achieve higher thermal efficiency.

6. What are the advantages of reheat cycle over simple rankine cycle?

1. It increases the turbine work.

2. It increases the heat supply.

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3. It reduces the wear on the blad3 due to the low moisture content in steam.

7. How the nuclear reactors are classified?

1. According to neutron energy

1. Fast reactors 2.intermediate reactors 3.slow reactors

2. According to moderator

1. Water 2.graphite 3.beryllium 4.hydrides

3. According to fuel

1. Solid 2.liquid 3.gas

8. What are the main units in gas turbine power plant?

1. Air compressor

2. Inter cooler

3. Regenerater

4. Combustion chamber

5. Gas turbine.

9. Why and when down comers placed outside the furnace?

If the boiler pressure is greater than 30 bars, the down comers are placed outside the furnace

so as to secure more density difference for natural circulation.

10. What do you understand by moderation?

Moderation is a process of deceleration of neutron energy from 2 me v to 0.25ev without

absorbing neutrons. The material used to reduce the kinetic energy is known as moderator .

UNIT 2

1. What is the transfer equipment of coal handling plant?

1. Belt conveyor

2. Screw conveyor

3. Bucket conveyor

4. Grab bucket elevators.

2. What are the essential functions of pulverizing mill in a steam power plant?

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1. Drying the coal

2. Grinding

3. Seperation of particles of desired size.

3. What are the functions of draught system?

1. to supply sufficient quantity of air through the furnace for complete combustion of

fuel.

2. To remove the gaseous products of combustion from the furnace.

4. What are the functions of electrostatic precipitator?

It is an electrically operated dust collector that is located in the path of flue gas between the

furnaces /boiler and the stack to remove the particulate matter especially fly ash in case of

pulverized fuel burning.

5. What are the types of cooling tower?

1. atmospheric cooling tower

2. natural draught cooling towers

3. Mechanical draught cooling towers.

6. Name the different types of burners used to burn pulverized of coal.

1. Long flame burner

2. Short flame burner

3. Tangential burner

4. Cyclone burner

7. What is the important action takes place in the pulverized mill to reduce ordinary coal to

its powder form.

1. Impact

2. Attrition

3. Crushing

8. What are the basic requirements of good ash handling system?

1. It should able to handle large clinkers ,soot and dust

2. It should be capable to deal with ultimate plant capacity ,

3. It should be able to handle both wet and dry ash and operate with little noise.

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9. What are the various operations of ash handling system?

1. Removel of ash from the furnace

2. Transfer of ash from furnace to isolated storage place by conveyors.

3. Disposal of stored ash.

10. List the advantages of natural draught system?

1. No external power is required for causing the draught.

2. Less capital investment and maintenance cost is almost nil

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Unit 3

1. What factors control the selection of a particular type of reactor?

1. Type of fuel to be used

2. Control system and coolant system

2. What is the function of moderator and reflector used in nuclear power plant?

Moderator:

It is a material which reduces the kinetic energy of fast neutron to increases the

probability of chain reaction.

Reflector:

it is used to reflect the escaping neutrons back into the core.

3. Name the coolants used for fast breeder reactor .

1. Liquid metal

2. Helium

3. Carbon di oxide

4. What are the components used in pressurized water reactor nuclear power plant?

1. Reactor core

2. Control rods

3. Moderator and coolant

4. Steam generator

5. Turbine

6. Condenser

5. Define the term breeding?

It is the process of fissionable material from a fertile material such as

uranium 238 and thorium 232 by absorbing the neutron with conversion ratio above unity .

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6. How the nuclear reactor is classified according to the type of moderator used?

1. Graphite reactor

2. Beryllium reactor

3. Water reactor .

7. Indicate the types of nuclear fission reactor power plants in India.

1. pressurised heavy water reactor-narora

2. pressurized heavy water reactor -kakrapur

3. pressurised heavy water reactor-kalpakkam

4. pressurised heavy water reactor-tarapur

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UNIT 4

DIESEL AND GAS TURBINE POWER PLANT

1. What are the essential components of a diesel power plant?

a) Engine

b) Air Intake system

c) Exhaust system

d) Fuel System

e) Cooling system

f) Lubrication System

g) Engine Starting system

h) Governing system

2. What are the commonly used fuel injection systems in a diesel power station?

a) Common rail injection system

b) Individual pump injection system

c) Distribution system

3. What are the methods of starting systems in large and medium size engines?

a) Starting by an auxiliary engine

b) Use of electric motors or self starters

c) Compressed air system

4. What are the methods of cooling the engine?

a) Air cooling

b) Water cooling

5. What is meant by Auto ignition?

In CI engine combustion occurs due to high temperature produced by the compression

of the air .

6. What is Delay period in CI engines?

It is defined as the time immediately following injection of the fuel during which the

ignition process is being initiated and the pressure does not rise beyond the value it

would have due to compression of air .

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7. What is diesel Knock?

If the delay period in CI engines is long a large amount of fuel will be injected and

accumulated in the chamber . The auto ignition of this large amount of fuel may cause

high rate of pressure rise and high maximum pressure which may cause knocking in

diesel engines.

8. Define Cetane Number .

It is defined as the percentage by volume of Cetane in a mixture of cetans and alpha

methyl naphthalene that produces the same ignition lag as the fuel being tested, in the

same engine and under the same operating conditions.

9. Define Mean effective pressure as applied to gas power cycles. How it is related to

indicate power of an IC engine?

Mean effective pressure is defined as the constant pressure acting on the piston during

the working stroke. It is also defined as the ratio of work done to the stroke volume or

piston displacement volume.

Mean Effective Pressure

Pm = (Indicated Power) / (Number of working stroke x Stroke volume per second)

10. Mention the various processes of Brayton cycle.

(a) Isentropic Compression

(b) Constant pressure heat supplied

(c) Isentropic expansion and

(d) Constant pressure heat rejection

11. What is the principle of operation of simple jet propulsion system?

When the works output of the gas turbine plant is used to produce high velocity jet of

hot gases and this jet is used to propel the vehicles in which the systems are mounted

such systems are kept as jet propulsion systems.

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UNIT 5

OTHER POWER PLANTS AND ECONOMICS OF POWER PLANTS

1. What is geothermal energy?

Geothermal energy is the heat from high pressure steam coming from within the earth.

It is a renewable source of energy derived from the rain water in the earth heated to

over 180°C by subterranean hot rocks.

2. What are the important criteria while selecting the geothermal energy?

a) Temperature of geothermal fluid, °C

b) Discharge rate, m3/day

c) Useful life of production well, years

d) Mineral contents, gram/m3

3. What are different types of OTEC?

a) Open cycle(Claude cycle, Steam Cycle)

b) Closed cycle ( Anderson cycle, Vapour cycle)

4. What are heliostats?

Heliostats are large, flat reflecting mirrors with a provision to track the sun in two

planes.

5. What is the significance of incremental rate for a power plant?

Boiler efficiency is defined as the ratio of heat energy used in system formation to the

heat energy supplied by burning of fuel in the same period but incremental heat rate is

the reciprocal of boiler efficiency.

6. What are the various operating costs of coal fired steam power plant?

a) Cost of fuel

b) Lubricating oil, grease and water cost

c) Cost of maintenance and repairs

d) Cost of operating labor

e) Cost of supervision

f) Taxes

7. Distinguish between peak load and connected load.

The peak load is the highest load which occurs on the power plant operation

throughout the cycle.

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Connected load is the combined continuous rating of all the receiving apparatus on

consumer’s premises.

8. Define Diversity factor

It is defined as the ratio of sum of the individual maximum demand to the actual peak

load of the system.

9. Define Depreciation.

It is the amount to be set aside per year from income to meet the depreciation caused

by the age of service, wear and tear of machinery.

10. List out important factors to be considered for selection of site for power plants.

a) Cost of land as well as taxes on land

b) It should be nearer to load centers

c) It should be accessible by road, rail

d) Sufficient quantity of cooling water should be available

e) The selected site should be away from populated area.

f) Enough space should be available for future expansion of plants

g) The selected site should satisfy geological factors.

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PART-B

UNIT - I

1. What major changes are required to convert existing oil fired boiler to FBC system?

2. Draw a line diagram of FBC system where gas turbine is used as prime mover . What

is the main advantage of this system?

3. Explain the difference between velocities compounding the pressure compounding

of steam turbines. Which is more preferred in practice and why?

4. Draw a neat line diagram of Benson Boiler and discuss its relative merits and

demerits.

5. Draw a neat diagram of Volex Boiler and discuss its merits and demerits with Benson

Boiler .

6. Calculate the power generated in MeV/cm3 and KW/m3 for a 3.5% enriched uranium

dioxide fuel element in a thermal reactor if the effective fission cross-section is 350

barns and the neutron flux per(cm2s) is 1014. The density of UO2 is 10.5 g/cm3.

7. A jet of 75 mm diameter strikes the bucket of an impulse wheel and gets deflected

by an angle of 1650. The speed of the bucket is 45.5 m/s. Find the velocity of the

jet for maximum efficiency and the power developed

8. Why is governing of hydraulic turbine necessary? Explain the governing mechanism

of a Kaplan turbine

UNIT - II

1. Describe different types of overfeed stokers and discuss the merit and demerits of each

over others.

2. Draw a neat diagram of multi-retort underfeed stoker and explain its working. Discuss its

merits over other types of stokers.

3. What are the requirements of the burners used for firing pulverized form ?

4. Draw a neat diagram of cyclone burner and describe its working. What are its outstanding

features compared with other burners? Why such burners are useful for Indian coals?

5. Draw a line diagram of hydraulic ash handling system used for modern capacity power

plant. Discuss its merits with other systems.

6. Draw a line diagram of pneumatic ash handling system. Explain the difficulties

encountered in its design and operation. When this system is preferred over other system?

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7. Explain the working of electrostatic precipitator with a neat diagram and list out its

outstanding features over other collectors.

8. What are the different methods used for flue gas conditioning? Describe one which is

commonly used giving its advantages over the other systems.

9. Explain the principle used in forced and induced draught. Why balanced draught is

preferred over forced or induced draught?

10. What are the different centrifugal fans used for draft system? Why the backward blade

fan is preferred for F .D fan and forward blade fan for I.D fan?

11. What different methods of control are used to control the air supply under variable

load conditions?

12. The draught produced by a forced draught fan is sufficient to overcome the total

frictional losses of the system 20 mm of water head and to impart the velocity of 10m/sec

to the flue gases passing through the chimney. The amount of coal burned per hour is

12.000 kg and air supplied is 12 per kg of coal burned. Assuming the atmospheric pressure

of 1.03 kgf/cm2 and temperature of 3000K and mechanical efficiency of 80%, find the

power required of a prime mover to run the fan assuming the mechanical efficiency of

80%.

13. Why steel chimneys are more preferred in Gas Turbine power plant than any other

chimney?

14. Discuss the important points in selecting steel or concrete chimney for a thermal power

plant. Give your preference with reason and an example of an Indian power plant.

UNIT - III

1. The number density of fuel atoms (N) of U-235 is 0.048 X 10 24 cm-3 and the microscopic

cross-section for absorption is 681x10-24 cm2. With a neutron flux of 2x1013cm-2s-1 , estimate

the reaction rate for absorption. What is the average distance traveled before striking a U-

235 nucleus?

2. Calculate the time required for the reactor power to double for (1) assumed fission with

prompt neutrons and (2) actual fission with prompt and delay neutrons. Take keff=1.002

3. Calculate the power generated in MeV/cm3 and KW/m3 for a 3.5% enriched uranium

dioxide fuel element in a thermal reactor if the effective fission cross-section is 350 barns

and the neutron flux per(cm2s) is 1014. The density of UO2 is 10.5 g/cm3.

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4. A BWR operating at a pressure of 70 bar produces 120Kg/s of a saturated steam from feed

water at 200oC. The average core exit quality is 10%. Calculate (a)the recirculation ratio,

(b) the core inlet enthalpy and temperature.(c) the degree of sub cooling, and (d) the

heat generated in the reactor .

5. A pelton wheel is required to develop 4500 KW at 400 rpm operating under an available

head of 360 m. There are two equal jets and the bucket angle is 170 0. The bucket pitch

circle diameter is 1.82 m. Taking k for the buckets as 0.85, determine (a) the efficiency of

the runner and (c) the diameter of each jet.

6. A jet of 75 mm diameter strikes the bucket of an impulse wheel and gets deflected by an

angle of 1650. The speed of the bucket is 45.5 m/s. Find the velocity of the jet for

maximum efficiency and the power developed.

7. Why is governing of hydraulic turbine necessary? Explain the governing mechanism of a

Kaplan turbine.

8. Derive an expression for the specific speed of a hydraulic turbine and calculate it for a

turbine operating under a head of 24 m and running at 400 rpm. The rate of discharge is

9m3/s and the overall efficiency is 90 per cent.

9. What are the advantages and disadvantages of a hydroelectric power plants in a over a

thermal one?

10. A run off 30m3/s is available at 7.5m head for generating the power . The turbine

efficiency is 85 per cent. (a) Is it feasible to develop this power by two turbines with rpm

of 50 and the specific speed of turbine not greater than 450?

UNIT - IV

1. During a 60-minute trial of a single cylinder four-stroke oil engine, the following

observations were made. Engine dimensions= 0.3 bore x 0.45 m stroke. Fuel consumption

11.4 kg. Calorific value of fuel = 42 MJ/kg, imep = 6 bar . Net load on brakes = 1500 N.

N=300 rpm. Brake drum diameter =1.8 m. Brake rope diameter =20 mm, Quantity of jacket

cooling water=600kg. Temperature rise of cooling water=550c, quantity of air as measured

= 250 kg. Exhaust gas temperature =420 0C, specific heat of exhaust gas=1.0KJ/KgK.

Ambient temperature= 200C. Estimate (a) the indicated power (b)the brake power and (c)

the indicated thermal efficiency.

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2. A four –cylinder , four stroke diesel engines develops 83.5KW at 1800 rpm with a bsfc of

0.231 Kg/k Wh and air-fuel ratio of 23/1. The analysis of the fuel is 87% carbon and 13%

hydrogen. The calorific value of fuel is 43.5MJ/kg. The jacket cooling water flows at 0.246

kg/s and its temperature rise is 50 0C. The exhaust temperature is 3160c. Draw up an

energy balance for the engine. Take R=0.302 KJ/KgK and Cp=1.09 KJ/kgK for the dry

exhaust gas and Cp=1.86 KJ/kgK for superheated steam. The room temperature is 17.8 0C

and the exhaust gas pressure is 1.013 bars.

3. Draw a plant layout for 5MW diesel power stations showing all the required equipments.

Show the arrangement of the cooling system and engine layout.

4. A cooling tower needed with a diesel plant will require to cool 900 litres of water at 67 0C

entering temperature. The DBT and WBT of atmospheric air are 28 0C and 22.5 0C

respectively . A forced draft tower with 70% cooling efficiency is used for cooling.

Calculate make-up water flow and estimate the fan power . Assume air goes out of tower

at 60 0C and 90% relative humidity .

5. Describe the working of a simple constant pressure open-cycle gas turbine plant giving a

neat sketch. How does actual cycle differ from the theoretical?

6. Draw a neat sketch and explain the working of a governing system used for closed cycle

gas turbine plant?

7. An open cycle constant pressure gas turbine plant takes air 27 0C. The maximum pressure

ratio and maximum temperature of the cycle are 4 and 950 K respectively . The isentropic

efficiency of compressor and turbine are 84% and 85% respectively . The effectiveness of

the regenerator is 0.6. Assuming the combustion efficiency 90% and neglecting the heat

and pressure losses in the system. Find the cycle efficiency and A:F ratio used. If the air

flow is 10Kg/sec. Find the generation capacity of the plant assuming mechanical efficiency

96% and generation efficiency 95%.

UNIT - V

1. Discuss different systems used for generating the power using geothermal energy?

2. Differentiate with neat sketches the difference between single basin and double basin

system.

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3. Explain the working of a vertical axis wind mill mentioning the specific arrangement of the

blades.

4. Describe the basic principle of photovoltaic and list out its merits over the other systems.

What are the main hurdles in the development of this mode of power generation?

5. What is the protection provided to a power plant against the consumer having: (a) high

maximum demand with poor load factor .

(b) high maximum demand with poor power factor

(c) low demand with high KVA demand.

6. The cost of coal and diesel oil are Rs.850 and Rs.2500 per tonne respectivelyThe calorific

value of coal and diesel are 20,000 KJ/Kg and 45,000 KJ/Kg Respectively .

The capital cost of steam plant = Rs.9800/KW

The capital cost of diesel plant = Rs.8700/KW

The fixed charges for both plants = 12% of Capital cost.

The steam plant requires few more men for operation than diesel and their annual

Salary is Rs.125 X106. Which plant should be selected and why?

7. Work out of two part tariff and overall generation cost in Rs./KW-h from the following

data for a generating station:

Capacity of plant = 100MW

Capital Cost = Rs.15000/KW

Maximum demand = 50MW

Annual L.F . = 0.4

Interest and depreciation =10% of capital cost/year

Annual Salaries =Rs.400 X 104

Annual fuel cost = Rs.350 x104

Annual cost of operation and maintenance = Rs.150x10 4

8. Design a two part tariff for the consumers from the following data:

Consumers maximum demand = 25 MW

Capital cost = Rs.12000/KW

Annual load factor = 0.4

Annual salaries and wages = Rs. 200 x10

Annual maintenance and repairs = Rs. 150 x10

Annual fuel cost = Rs. 2000 x10

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Losses in transmission and distribution= 10%

Interest and depreciation =10% of capital

Load diversity factor =1.4

9. A power station has an installed capacity of 20 MW. The cost of the plant is Rs.12000/KW

installed. The fixed charges are 13% of the investment. At 100% load factor , the variable

costs of the station per year are 1.5 times the fixed costs. Assuming there is no reserve

capacity and variable cost are proportional to the energy production, find the cost of

generation of 100%,80%,60%, 40% and 20% load factor . Plot the curve.

10. Find the cost of generation per KW-hr from the following data:

Station capacity =100MW

Capital cost =Rs.12000/KW-installed

Annual charges = 10% of capital

Fuel Consumption =0.7 kg/kW-hr

Cost of fuel = Rs.500/tonne

Salaries and wages = Rs.600x10

Maximum demand =60Mw

Load factor =30%