power plant engineering...absorption machine (vam) working on the principle of vapour absorption...

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T.Y. Diploma : Sem. V [ME]

Power Plant Engineering Time: 3 Hrs.] Prelim Question Paper Solution [Marks : 70

Q.1 Attempt any FIVE of the following : [10]Q.1(a) List different types of Power plant. [2]Ans.: Power plants can be classified as, Conventional Power Plants: (i) Thermal Power Plant

(ii) Diesel Power Plant (iii) Nuclear Power Plant (iv) Hydro-electric Power Plant Non-Conventional Power Plants: (i) Solar Power Plant (ii) Wind Power Plant (iii) Geo-Thermal Power Plant (iv) Biomass Power Plant

Q.1(b) Name any four components of FBC Boiler. [2]Ans.: Components of FBC Boiler Coal and Lime-stone hopper Air distributor Fluidized bed Water tubes Fly-ash recycle device Dust collector Air pre-heater Exhaust system Q.1(c) Classify Fuel handling system in Steam Power plants. [2]Ans.: Fuel handling system: Coal delivery Unloading Coal preparation Transfer Q.1(d) State the Necessity of Waste Heat recovery in Thermal power plants. [2]Ans.: Need of waste heat recovery: To improve efficiency: (i) With the waste heat recovery unit, waste heat energy can be recycled. (ii) This increases overall output of the plant with same input. (iii) This increases overall efficiency of plant or operation.

To reduce energy consumption: (i) With the waste heat recovery unit, desired output can be obtained at comparatively

lesser input. (ii) This enables plant or operation to operate at lower input and reduce energy

consumption.

To reduce operating cost: (i) When waste heat is recycled, plant or operation can be operated at lower input. (ii) This reduces fuel consumption and hence operating cost of fuel.

Vidyalankar : T.Y. Diploma PPE

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To decrease waste and emission: (i) When waste heat is recycled, fuel consumption reduces. (ii) Since burning of fuel produces air pollutants, emissions can be reduced by reducing

fuel consumption. Q.1(e) Name any two regulating Agencies for Nuclear power plants. [2]Ans.: Regulation agencies for nuclear power plant Atomic Energy Regulatory Board International Atomic Energy Agency Q.1(f) State the need of IBR [2]Ans.: IBR means Indian Boiler Regulation. It governs design, manufacture, installation and

operation of all steam producing vessels which falls under its purview. Q.1(g) State any four advantages of Diesel Power Plants. [2]Ans.: Advantages of diesel power plant: The diesel power plants are more efficient than steam power plants. Efficiency of diesel

power plant is in range of 50% to 100%. For small capacity, diesel power plants are cheaper as compared to steam power plants. It has no standby losses. It can burn fairly wide range of fuels. It can start quickly. The space required for diesel power plant is considerably less as compared to thermal

power plant. Q.2Attempt any THREE of the following : [12]Q.2(a) State the National Scenario of Demand and Supply of Energy. [4]Ans.: A. India is 11th greatest power producer in world ranking. On the other hand, India is

6th greatest power consumer in world. India’s net energy requirement is far more than net power developed by country. Hence

India is energy importer. Power Resources: - Coal dominates the energy supply in India, contributing to 55% of the total

primary power production. - Major Energy Resources in India: (a) Coal: India has huge coal reserves, at least 84x103 million tonnes of proven

recoverable reserves. This amounts to almost 9% of the world reserves and it may last for about

230 years. Whereas, the world's proven coal reserves are expected to last only for

192 years. (b) Oil: Oil shares about 36 % of India's total energy consumption. India today is one of the top ten oil consuming nations in the world. The country's annual crude oil production is peaked at about 32million

tonnes as against the current peak demand of about 110 million tonnes. (c) Natural Gas: Natural gas accounts for about 9 % of energy consumption in the country. The current demand for natural gas is about 96 million cubic metres per day

as against availability of 67 million cubic metres per day. (d) Nuclear Power: Nuclear Power contributes to about 2.4% of electricity generated in India.

Prelim Question Paper Solution

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India has ten nuclear power reactors at five nuclear power stations producing electricity.

(e) Hydro-Electric power: India is enriched in terms of hydro potential for power generation. Out of total hydro potential only 15% has been harnessed so far. The share of hydropower in the country's total generated units has steadily

decreased. (e) Power Consumption: The sector-wise power consumption in India

Q.2(b) Explain with neat sketch the principle of FBC with neat sketch. [4]Ans.: Working principle of fluidized bed combustion boiler can be illustrated with figure

shown below. Simple fluidised bed combustion which has a distributor or perforated support plate

on which finely divided particles of fuel (6 mm-20 mm) are provided. Air is passed in the upwards direction with low velocities. The pressure drop across the combustion chamber can be measured with the help of a

manometer.

The velocity of air is gradually increased and the graph of log of ΔP and log of velocity

v is plotted.


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Up to point A, the bed is stable. Between A and B – The bed is unstable particles adjust their position to present as

little resistance to flow as possible. At B, the particles are just in contact with each other. Beyond point B, on further increase in velocity, the particles start moving freely in

the bed with frequent collisions with each other. Point B is called the point of fluidisations and the corresponding velocity is called the minimum fluidisation velocity.

Beyond point B, on further increase in velocity, the resistance to flow decreases as freely suspended in gas stream. In this state, the bed continues to expand, and it becomes turbulent; also there is rapid mixing of particles. Under these conditions the mixture of bed and gas behaves like a fluid and the burning of fuel in such a state is called fluidized bed combustion.

It consists of a shell with a distributor plate at its bottom with holes in it. The shell carries the boiler evaporator tubes which remain immersed in the fluidized bed as shown. Coal of 6 to 20 mm size with dolemite or lime stone are fed on the distributor plate. Air is supplied from the bottom at a velocity more than the minimum velocity of fluidisation.

The heat energy released due to combustion is rapidly transferred at high rates to water in the evaporator tubes and the generated steam is taken out. The sulphur content of the coal is converted into SO2 on burning and SO2 is mostly absorbed by dolemite. Hence the flue gases leaving the bed are almost free from SO2 gas. The molten ash formed is taken out from the top as shown. Such a system reduces the size of the boiler considerably due to high rates of heat transfer.

Q.2(c) Explain the working of ‘Open Type Gas Turbine with neat sketch. [4]Ans.: Construction Main components of open cycle gas turbine power plant are: Compressor Combustion chamber, and Turbine. Working The working of open cycle gas turbine follows constant pressure process. A starting motor is required to run the compressor initially. Atmospheric air is compressed in the compressor. This compressed air is supplied to the combustion chamber. Fuel supplied in the

combustion chamber is ignited with the help of oxygen present in the compressed air to produce hot gases.

Increased internal energy of hot gases during combustion is converted into kinetic energy with the help of nozzles. These high velocity jets of hot gases are made to strike over the blades of turbine rotor, thus making the rotor to rotate.

Thus, kinetic energy is converted into mechanical energy or work, which is now made available at turbine’s output shaft.

As soon as the turbine starts to produce the mechanical work, the starting motor is made shut-off.

Major portion of this mechanical work made available at turbine shaft is supplied to run the compressor.

Remaining quantity of power (i.e. mechanical work) produced by turbine is used to generate electric power.

For this purpose, a generator is coupled to turbine, which converts mechanical energy (work) into useful electrical energy.


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Q.2(d) Explain the Term ‘Trigeneration’? State its necessity in thermal power Plant. [4]Ans.: Figure shows a typical trigeneration layout. The system incorporates a prime mover, which is directly connected to an electrical

generator. Exhaust gases are transferred to a heat exchanger before being released into the atmosphere.

Prime mover shown in the figure may be gas fired engine, gas turbine, diesel engine etc. In addition to prime mover and electric generator, trigeneration plant has a vapour

absorption machine (VAM) working on the principle of vapour absorption refrigeration cycle and a heat exchanger.

We know that, in case of vapour absorption refrigeration cycle, compressor of vapour compression refrigeration system is replaced by a generator (Not electric generator, which is used to produce electricity), because large amount of electricity is required to run the compressor. The other major components like condenser, expansion device and evaporator remain the same.

Also, due to absence of compressor, operation of vapour absorption machine running on vapour absorption refrigeration cycle becomes noiseless.

Here, in vapor absorption machine, refrigerant used is water and absorbent used is lithium bromide.

Let us consider that, the prime mover is a gas fired engine, where natural gas is used as fuel.

On combustion of natural gas in engine, high pressure and high temperature gases are produced, which contain large amount of heat energy. These gases undergo expansion and produce mechanical energy, which drives the electric generator and thus, electricity is produced.

During conversion of heat energy into mechanical energy (work), large amount of heat (about 65% of total heat produced in engine) is released to atmosphere, which is considered as heat loss. This heat is called as waste heat, which is further utilized for heating and cooling purposes by adopting the method of trigeneration.

Some portion of this waste heat is sent to heat exchanger, where the cold water gets heated to give hot water. Instead of heating the water, this waste heat can be used for various heating purposes.

At the same time, some portion of waste heat is supplied to generator of vapour absorbing machine, which contains strong solution of water and lithium bromide. Due to heat gain, water (refrigerant) gets vaporized and separated from lithium bromide. Due to vaporization, water vapurs are formed. These water vapurs are sent to condenser of vapour absorption system, where they are cooled and condensed to give low temperature water. This low temperature water enters the expansion device (not shown in figure), where its pressure is reduced. Due to decrease in pressure, the temperature of water is further reduced.

The low pressure, low temperature water enters the evaporator or the space to be cooled, where it absorbs the latent heat required for its vaporization and gets


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vaporized. Thus, cooling effect is achieved in the evaporator or space to be cooled. The water vapours so formed are sent to absorber, where weak solution of lithium bromide and water is available. As more and more water vapours are mixed with lithium bromide, we get strong solution of lithium bromide and water. This strong solution is then sent to generator and this vapour absorption cycle is repeated again and again to give cooling effect.

Water (refrigerant) and lithium bromide salt (absorbent) are generally used for generation of chilled water in the temperature range from 6 to 12C.

Fig.: Working principle of trigeneration plant

Ammonia (refrigerant) and water (absorbent) are used for low temperature chilling

down to - 60C. Thus, the electrical generator provides building electrical requirements, the vapour

absorption machine (i.e. refingerator) provides cooling and the heat exchanger provides the heating means.

Q.3 Attempt any THREE of the following : [12]Q.3(a) Draw general layout of Hydro-Electric Power plant showing all components. [4]Ans.:

Q.3(b) Explain the working of Electrostatic Principle with neat sketch. [4]Ans.: Introduction: An electrostatic precipitator is an electromechanical device which filter outs fine

particles like fly-ash, dirt, dust etc from flue gas before releasing it out of chimney.


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Working principle: The basic principle of electrostatic precipitator is that fine particles in flue gas (mainly

fly-ash, dirt dust) are ionised by the high voltage discharge electrode by the CORONA EFFECT.

The ash particles ionise to negative charge and are attracted to the positively charged collector plates.

Construction:

It consists of following components: - High voltage source (440 V, 50 HZ and 3ɸ Supply) - Ionizing or collecting electrodes - High voltage transformer - Rectifier (Ac to DC converter) It consists of two sets of electrodes: positive and negative. The negative electrode (Discharge electrodes) are in the form of a wire mesh and the

positive electrodes (Collecting electrodes) are in the form of plates. The negative electrodes (Discharge electrodes) are in the form of a wire mesh and the

positive electrodes (Collecting electrodes) are in the form of plates. These electrodes are vertically placed and are alternate to each other. The negative terminal of high voltage DC source is used to connect the negative

electrodes and the positive electrode are grounded. To ionize the medium between the negative and the positive electrode, a certain

distance is maintained between the positive, negative electrode and the DC source resulting in a high voltage gradient.

The medium that is used between the two electrodes is flue gas. Working: The entire system is enclosed in a metallic container consisting of an inlet for flue gases

and an outlet for filtered gases. Ionization of gas occurs at 40 to 80 kV and at this stage positive and negative ion are

formed. Positive ions travel towards negatively charged electrodes (discharge electrodes). While negative ions travel towards positive charged electrodes (collecting electrodes). There are plenty of free electrons as the electrodes are ionized which interact with the

dust particles of the gas making them negatively charged. These particles move towards positive electrodes due to electrostatic force. Now the flue gas is free from the dust particles as it flows through the electrostatic

precipitator and discharged to the atmosphere through the chimney. Advantages: The durability of the ESP is high. It can be used for the collection of both dry and wet impurities. It has low operating costs.


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The collection efficiency of the device is high even for small particles. It can handle large gas volumes and heavy dust loads at low pressures. Disadvantages of electrostatic precipitator: It cannot be used for gaseous emissions. Space requirement is more. Capital investment is high. Not adaptable to change in operating conditions. Q.3(c) Explain with neat sketch the working principle of Cogeneration. [4]Ans.: Principle of Cogeneration Cogeneration or Combined Heat and Power (CHP) is defined as the sequential generation of

two different forms of useful energy from a single primary energy source, typically mechanical energy and thermal energy. Mechanical energy may be used either to drive an alternator for producing electricity, or rotating equipment such as motor, compressor, pump or fan for delivering various services. Thermal energy can be used either for direct process applications or for indirectly producing steam, hot water, hot air for dryer or chilled water for process cooling.

Cogeneration provides a wide range of technologies for application in various domains of

economic activities. The overall efficiency of energy use in cogeneration mode can be up to 85 per cent and above in some cases.

Fig.: Cogeneration Advantage

For example in the scheme shown in figure an industry requires 24 units of electrical energy and 34 units of heat energy. Through separate heat and power route the primary energy input in power plant will be 60 units (24/0.40). If a separate boiler is used for steam generation then the fuel inut to boiler will be 40 units (34/0.85). If the plant had cogneration then the fuel input will be only 68 units (24 + 34)/0.85 to meet both electrical and thermal energy requirements. It can be observed that the losses, which were 42 units in the case of, separate heat and power has reduced to 10 units in cogeneration mode.

Along with the saving of fossil fuels, cogeneration also allows to reduce the emisssion of

greenhouse gases (particularly CO2 emission). The production of electricity being on-site, the burden on the utility network is reduced and the transmission line losses eliminated.


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Cogneration makes sense from both marcro and micro perspectives. At the macro level, it allows a part of the financial burden of the national power utility to be shared by the private sector; in addition, indigenous energy source are conserved. At the micro level, the overall energy bill of the users can be reduced, particularly when there is a simultaneous need for both power and heat at the site, and a rational energy tariff is practiced in the country.

Q.3(d) Compare between Boiling water reactor (BWR) and Pressurized water Reactor

(PWR). [4]

Ans.:

Sr. No.

Comparative point PWR BWR

(i) Heat exchanger Required. Not required. (ii) Pressure of water in

core 130-150 bar. 70 bar pressure with

250C temperature. (iii) Efficiency Low efficiency as

compared to BWR High efficiency as compared to PWR.

(iv) Cost High. Less (v) Reactor type High-pressure reactor. Low-pressure reactor. (vi) Number of pumps Two pumps i.e. Feed

pump and circulating pump are required.

Only one pump i.e. feed pump is required.

Q.4 Attempt any THREE of the following : [12]Q.4(a) Explain the maintenance procedure of Diesel generating set. [4]Ans.: Maintenance schedule for diesel power plant: Maintain log sheet which include instrument readings and condition of components. Periodic checking of pressure, temperature and electric load is necessary. During maintenance cleaning of oil is done using filters. Replaced chocked filters by new filters. Check the temperature of coolant flow, lubrication oil and exhaust gas at regular

intervals. Make sure that radiator is filled with sufficient coolant or cold water. Q.4(b) Name any four Nuclear power plant situated in India with their Capacity. [4]Ans.: List of Nuclear Power Plants in India

Sr. No.

Name of the power station

State Operator Total capacity

1. Tarapur Atomic Power Station

Maharashtra NPCIL 1,400

2. Kakrapar Atomic Power Station

Gujarat NPCIL 400

3. Kudankulam Nuclear Power Plant

Tamil Nadu NPCIL 2,000

4. Kaiga Nuclear Power Plant

Karnataka NPCIL 880

5. Madras Atomic Power Station

Tamil Nadu NPCIL 440

6. Rajasthan Atomic Power Station

Rajasthan NPCIL 1,180

7. Narora Atomic Power Station

Uttar Pradesh

NPCIL 440


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Q.4(c) State the need of Cogeneration. [4]Ans.: Thermal power plants are a major source of electricity supply in India. The conventional

method of power generation and supply to the customer is wasteful in the sense that only about a third of the primary energy fed into the power plant is actually made available to the user in the form of electricity (Figure). In conventional power plant, efficiency is only 35% and remaining 65% of energy is lost. The major source of loss in the conversion process is the heat rejected to the surrounding water or air due to the inherent constraints of the different thermodynamic cycles employed in power generation. Also further losses of around 10-15% are associated with the transmission and distribution of electicity in the electrical grid.

Q.4(d) State any four applications of Diesel Electric power plants. [4]Ans.: Diesel engine power plants are quite suitable for mobile power generation and they are

widely used in transportation systems consisting of railroads, ships, automobiles and aeroplanes.

They can be used for electrical power generation of capacities from 100 kW to 5000 kW. They can be used as peak load plants for some other types of power plants. They can be used as emergency power plants, i.e. standby power plants. They can be used in small scale industries. They can be used for small nursery stations. They can be used as small capacity central stations. Q.4(e) Thermal power plants consists of two 50 MW units, each running at 6000 hours

and one 20MW units runs at 3000 hours per year. Energy produced by the plantis 840 x 106 kWh per year. Find Plant load factor and plant use factor.

[4]

Ans.: Given: Energy produced per year = 840 × 106 kw 2 units of 50 mw running at 6000 hours per year.

Fig.: Cogeneration Plant


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1 unit of 20 mw running at 3000 hours per year. To find: (i) Plant load factor (ii) Plant use factor Solution: (i) Average Load Energy produced per year = Average Load × Total number of hours per

year 840 × 106 = Average Load × [365 days/ year × 24 hours/ day]

Average Load =

6840x10365 24

Average Load = 95.890 × 103 kw = 95.89 mw. (ii) Plant Capacity

Plant capacity = [50 × 2] +20 Plant capacity = 120 mw.

Assuming plant capacity = Maximum demand. Maximum demand = 120 mw

(iii) Load factor

Load factor =

Average LoadMaximumDemand

= 95.89120

Load factor = 0.7990 = 79.90% (iv) Plant use factor

Plant use factor =

Annual energy producedcapacity of number of plant operating

plant hours per year

=

840 102 50 6000 1 20 3000

Plant use factor = 1.27 Q.5 Attempt any TWO of the following : [12]Q.5(a) Explain the constructional feature of Schmidt Hartman boiler with neat sketch. [6]Ans.: History: It is invented by Schmidt and Hartmann. Type: Schmidt-Hartmann boiler is high pressure, water tube and forced circulation steam

boiler. Working Principle: Two pressures can be used to affect an interchange of heat energy. Construction: Main components of Schmidt-Hartmann Boiler are: - Feed Pump - Feed Pre-heater - Evaporator - Superheater The arrangement of the components of Schmidt-Hartmann boiler is as shown in figure.


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Working: Schmidt-Hartmann boiler working operation is similar to an electric transformer. In the primary circuit, the steam at 100 bar pressure is produced from the distilled

water. This steam is passed through a submerged heating coil which is located in a steam

generator (evaporator drum) as shown in the figure. The high-pressure steam in this coil possesses sufficient thermal potential and steam at

60 bar pressure with a heat transfer rate of 2.5 kW/m2 °C is generated in the evaporator drum.

The steam produced in the evaporator drums (steam generator) from impure water is further passed through the superheater and the super-heated steam produced in the super-heater is supplied to the prime mover.

The high-pressure condensate formed in the submerged heating coil is circulated through a low-pressure feed heater on its way to raise the feed water temperature to its saturation temperature.

Therefore, only latent heat is supplied in the evaporator drum. Natural circulation is used in the primary circuit and this is sufficient enough to effect

the desired rate of heat transfer and to overcome the thermo-siphon head of height about 2 to 10 meters.

In normal circumstances, the replenishment of distilled water in the primary circuit is not required as every care is taken in design and construction to prevent leakages.

But as a safeguard against leakage accidental loss, a pressure gauge and safety valve are fitted in the Schmidt-Hartmann boiler’s circuit.

Q.5(b) Draw schematic Diagram of Boiler Feed water control system. State its

importance in thermal power plant. [6]

Ans.: Feed water control system is used to control the flow of feedwater and, thereby, flow of steam to meet the load demand by the turbine.

At the same time, feedwater control system maintains the level of water in the steam drum within relatively narrow limits.

Normally, the water level in the drum is maintained half full up to the diametral plane. A high consumption by the turbine combined with low feed water supply would lower the

water level in the drum. The three elements automatic control system is shown in which the three elements are, - Drum Level - Feed water level - Steam flow


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In case of high steam consumption and low feed water supply, the drum level will fall below the set point

The drum level sensors respond to such errors and acts on the controller to increase feedwater valve opening to meet steam flow demand.

This action may be too slow. Therefore, it is supplemented by sensors for feedwater and steam flow.

The difference between the signals from these two sensors predicts the changes in drum level and the signal is sent to the controller to actuate the valve in the desired action.

Q.5(c) State the various factors to be considered for cost analysis of generation of

electricity. [6]

Ans.: The ultimate aim of power plant design is to produce electrical energy at minimum cost and higher efficiency.

The generation cost per unit kWh depends upon the cost of creating design, erection, commissioning and operation of power plant.

The two basic categories of cost are, (A) Fixed cost (B) Operating cost. (a) Fixed Cost Fixed cost is usually incurred only once during the life of plant. Fixed cost has following components: 1. Capital cost of power plant: It includes, (i) Purchase of land, land development etc. (ii) Purchase of machinery and equipment and their installation. (iii) Engineering and architectural fee of that project. 2. Capital cost of primary distribution system: It includes, (i) Cost of construction of transmission line. (ii) Cost of construction of substation – its building and equipments. 3. Interest, Taxes and Insurance: (i) Interest on capital cost Many times, capital cost or part of capital cost is usually borrowed and the

borrower has to pay the interest. This payment is called as interest on capital cost.

It is expressed in the terms of rate. For example, 5% interest on the capital cost is ` five per year per ` one

hundred. (ii) Taxes The management has to pay various taxes to town and state authorities such

as property tax, land tax etc. They are usually paid on annual basis. (iii) Insurance The heavy investment made has to be protected from the risk of fire,

explosion, storms, earthquake, flood etc.


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The insurance premium depends upon sum assured and the period. It is usually paid on annual basis.

4. Depreciation Every equipment depreciates due to corrosion, erosion, wear and tear with use.

Therefore, when the equipment failure occurs and it stops working, then this old equipment has to be replaced with new equipment.

The cost of new equipment will also be referred as the capital investment. Therefore, some cost must be recovered from the income of power plant to meet this depreciation cost.

Therefore, every year a particular amount (called as depreciation amount) is kept aside from the profit, so as to purchase new equipment after the old one is discarded or disposed off.

The most common methods for calculating depreciation amount are: (i) Percentage method.

(ii) Unit method.

(iii) Straight the method, for which, A = P Sn

(iv) Sinking fund method, for which, A =

n

rP S

1 r 1

Where, P = Initial investment S = Salvage value at the end of plant life n = Life of plant in years r = Annual rate of interest on the invested capital A = Depreciation amount set aside per year. 5. Managerial cost It includes salaries and wages of the people working in the plant during

construction stage. (b) Operating Cost/Variable Cost Operating cost means the expenditure incurred for operating the power plant to

produce electrical energy. Operating cost includes: 1. Cost of fuel (except the case of hydroelectric power plant): (i) Fuel contributes to larger extent in calculation of operating cost. (ii) The cost of fuel includes not only its price, but it also includes its

transportation cost and handling cost. (iii) Cost of fuel is nearly 70% of operating cost. 2. Cost of salaries and wages (i) The management has to appoint many supervisory staff and contract

labour for economic operations of power plant. (ii) The salaries or wages paid are considered under operating cost. 3. Cost of maintenance and repair (i) Periodic and preventive maintenance is done in order to avoid the breakdown

of power plant. (ii) This includes inspection, cleaning, overhauling, greasing etc. on regular

schedule. (iii) Repairs are also necessary, when the plant is under break down. 4. Operating taxes (i) When the power plant starts producing electric power, the

management will start to earn profit by selling it to consumer. (ii) At soon as the management starts earning profit, it has to pay several

taxes to government such as income tax, sales tax.


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Q.6 Attempt any TWO of the following : [12]Q.6(a) Explain the Indian Boiler Regulation (IBR) act. Name the inspecting and

competent authority suggested by IBR. [6]

Ans.: The Indian boiler Regulation Act, 1923 is shortly abbreviated as IBR, 1923. It is an act of law. It governs the

1. Manufacture 2. Installation 3. Operation and 4. Maintenance of boilers.

In IBR act it was specified that a government officer would be responsible and would have to certify all steam boilers from safety point of view.

A local IBR officer is from state government and they must keep watch to each industrial zone. It is mandatory to invite local inspector to inspect boilers and accessories.

State government must define the local limits within which, inspector shall exercise the inspection.

Every consumer running IBR certified boiler, must carry out IBR annual inspection in presence of IBR inspector.

State government must appoint qualified person as Chief Inspector and Deputy Chief Inspector.

Boiler and IBR definition: As per IBR act, boiler can be defined as ‘A vessel containing greater than 22.5 litres of

water used to generate the steam. Any boiler having capacity more than 1000 kg/hr is IBR boiler. Manufacturing of IBR boilers and equipment: To manufacture IBR boiler components and equipment IBR license is required. IBR license is basically factory approval for manufacturing various boiler components

and process required for manufacturing boiler i.e. welding. Once license it received from IBR, raw material is to be purchased from IBR approved

vendors only. Moreover, manufactured component must be purchased from IBR approved vendors only. The manufacturing can be done as per guidelines provided by IBR. During manufacturing, for each unit, IBR authorities must be employed for inspection. If IBR inspector finds manufactured boiler is within standard provided by IBR, he/she

shall issue certificate of approval. If IBR inspector finds manufactured boiler is not within standard provided by IBR,

he/she shall issue certificate of refuse. If IBR inspector finds that even after giving necessary instruction, manufacturer

couldn’t perform necessary rectification boiler, he/she shall have authority to punish the manufacturer either by charging a fine or penalty as described in IBR.

Repairing of Boiler and boiler components: No one should repair boiler or boiler components, unless he has necessary facilities in

premises. In case, power plant doesn’t have necessary facilities for boiler repairing in premises,

they shall engage a boiler repairer having ‘Boiler repairer certificate’.


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Design and drawing of boiler and boiler components should be as per guidelines provided by IBR.

The materials, mounting and accessories used during repairing must be as per guidelines provided by IBR.

A person employed for Welding must have Welder certificate issued by authority.

Report of Accident As per IBR, boiler can be defined as ‘an explosion of boiler or steam pipe or any damage

to boiler or steam pipe’. If any accident occurs due to boiler or boiler components, owner shall submit report in

24 hours to authority. Report should contain true description of accident regarding nature of accident, damage

to boiler or boiler components or injury to any person. IBR authority judges the severity of accident based on this report.

Every person is bound to answer truly to the best of his/her knowledge and put it in writing in front of IBR inspector regarding inspector.

If there is any loss of human life, inquiry can be conducted by State government of central government.

Registration and renewal of certificate: Any owner which is not registered under IBR, may submit application to inspector along

with necessary documents. All such applications must be submitted along with necessary fees. IBR inspector shall fix a date (within 30 days of date of receipt) for the examination of

boiler. An authorizing certificate to use boiler is valid till:

1. Expiry date of granted period 2. Any accident occurs 3. Boiler is to be shifted from one place to another place.

Penalties for illegal use of boiler: Any boiler owner who uses boiler either without certificate of approval shall be fined as

per guidelines provided by IBR.

Any person who has transferred boiler from one place to another place without report shall be punished by IBR.

Q.6(b) Draw a layout of Typical Fuel Handling System used in Thermal Power Plant. Namethe different components used in Fuel Handling system.

[6]

Ans.: Coal delivery equipment is one of the major components of plant cost. The various steps involved in coal handling are as follows: (i) Coal delivery (ii) Unloading (iii) Preparation (iv) Transfer


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(i) Coal Delivery The coal from supply points is delivered by ships or boats to power stations

situated near to sea or river. The coal is supplied by rail or trucks to the power stations which are situated

away from sea or river. The transportation of coal by trucks is used if the railway facilities are not

available.

(ii) Unloading The type of equipment to be used for unloading the coal received at the power

station depends on how coal is received at the power station. If coal delivered by trucks, there is no need of unloading device as the trucks

may dump the coal to the outdoor storage. Coal is easily handled if the lift trucks with scoop are used. In case the coal is brought by railways wagons, ships or boats, the unloading

may be done by car shakes, rotary car dumpers, cranes, grab buckets and coal accelerators.

Rotary car dumpers although costly are quite efficient for unloading closed wagons.

(iii) Preparation If the coal is not of proper size it is needed to be prepared for combustion. Coal preparation is carried out by: 1. Breakers 2. Crushers 3. Sizer 4. Dryers 5. Magnetic Separators

(iv) Transfer: Transfer means the handling of the coal between the unloading point and the

final storage point.

Coal delivery

Unloading

Preparation

Transfer

Outdoor storage (Dead storage)

Inplant handling

Weighing and measuring

Covered storage (Dead storage)

Fumace firing


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The following equipment are used for transfer of coal: 1. Belt conveyor 2. Screw conveyor 3. Vee bucket elevator and conveyor 4. Pivot bucket conveyor 5. Grab bucket conveyor 6. Flight conveyor 7. Skip hoist 8. Mass flow conveyor Q.6(c) Peak load on power plant is 60 MW. The load having maximum demand

30MW.20MW.10MW and 14MW connected to power plant. The capacity of powerplant is 80 MW and load factor 0.5. Estimate (i) Energy supplied per year (ii) Demand factor (iii) Diversity factor

[6]

Ans.: Given: Peak load = 60 mw Maximum demand = 30 mw, 20 mw, 10 mw and 14 mw. Capacity of plant = 80 mw. Load factor = 0.5 To find: (i) Energy supplied per year (ii) Demand factor (iii) Diversity factor

(i) Average Load

Load factor = AverageLoadPeakLoad

0.5 = Averagae Load60

Average Load = 30 mw (ii) Energy Supplied per year Energy supplied per year = Average Load × number of operating hours

per year = 30 × [24 hours/ day × 365 days/ year] Energy supplied per year = 262800 mw.hr. = 262.8 × 106 kw.hr (iii) Demand factor

Demand factor =

MaximumdemandConnectedload

=

6030 20 10 14

Demand factor = 0.8108 (iv) Diversity factor

Diversity factor =

sumofindividualmaximumdemandSimultaneous maximumload

= 7460

Diversity factor = 1.233

power plant engineering...absorption machine (vam) working on the principle of vapour absorption...

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