Energy Engineering Orals/Viva Question Answers

Energy Engineering Orals/Viva Question Answers

1. What is the full form of NTPC, MNRE?
Ans. NTPC Limited, formerly known as National Thermal Power Corporation Limited, is an Indian statutory corporation. It engaged in generation of electricity and allied activities. It is a statutory corporation incorporated under the Companies Act 1956 and is under the ownership of Ministry of Power, Government of India.

The Ministry of New and Renewable Energy (MNRE) is the nodal Ministry of the Government of India for all matters relating to new and renewable energy.

2. Define Carbon Credit.
A carbon credit is a permit that allows the owner to emit a certain amount of carbon dioxide or other greenhouse gases. One credit permits the emission of one ton of carbon dioxide or the equivalent in other greenhouse gases. The carbon credit is half of a so-called "cap-and-trade" program.

3. What do you understand by load shedding?
Load shedding is when power companies reduce electricity consumption by switching off the power supply to groups of customers because the entire system is at risk. This could be because there is a shortage of electricity supply, or to prevent transmission and distribution lines from becoming overloaded.

4. Name some thermal power plants and hydropower plants in Maharashtra.
Thermal Power Stations Coal based
  1. Chandrapur Super Thermal Power Station - 2920 MW.
  2. Koradi Thermal Power Station - 3660 MW.
  3. Khaparkheda Thermal Power Station - 1340 MW.
  4. Bhusawal Thermal Power Station - 1420 MW.
  5. Nashik Thermal Power Station - 630 MW.
  6. Parli Thermal Power Station - 1130 MW.

 Hydropower plants in Maharashtra
  1. Bandardhara Hydroelectric Project Godavari
  2. Bhatgarh Hydroelectric Project Krishna
  3. Bhatsa Hydroelectric Project West flowing rivers from Tapi to Tadri
  4. Bhira Hydroelectric Project Krishna, West flowing rivers from Tapi to Tadri

5. State advantages and limitations of solar energy.

Advantages & Disadvantages of Solar Energy – 7 Pros and Cons
Advantages of Solar Energy
  • Reduces Electricity Bills
  • Provides Tax Incentives
  • Pairs with Solar Battery Storage
  • Environmentally Friendly

Disadvantages of Solar Energy
  • High Initial Costs
  • Time Consuming
  • Weather Dependent
  • Stringent Criteria

6. How you define overall efficiency power plant.
Overall Efficiency of Thermal power plant is the ratio of equivalent heat energy which is ultimately converted to electrical energy coming from turbine shaft to the heat energy of coal combustion.

7. What are the factors affecting selection of site for thermal power plant.
The major factors taken into consideration while locating a thermal power plant are:
  • Terrain.
  • Availability of Fuel and Water.
  • Proximity to population centres.
  • Accessibility.

8. How do you classify steam power plants.
Steam turbines can be classified in a number of ways. They can be classified by cycle and steam conditions, such as Rankine cycle, Rankine regenerative cycle, reheat cycle, condensing or noncondensing, and by the number and arrangement of turbine shaft shafts and casings.

9. Name 4 circuits of a coal based thermal power plant.

The coal based thermal power plant comprises of four main working circuits:
  • Coal and ash circuit.
  • Air & gas circuit.
  • Feed water and steam flow circuit.
  • Cooling water circuit.

10. List the advantages and disadvantages of steam power plants.

  • Cheap coal is used
  • Can be installed anywhere near fuel & water supply
  • Requires less construction space
  • Cost for Generation is less

  • Air pollution from smoke fumes
  • Costs more to run compared with other types of power stations

11.What do you understand by pulverized coal. What are its advantages?
Pulverized coal produces more amount of heat, thus boiler efficiency is increased and generates about 2000 tonne/hr of steam in one boiler. By arranging the pulverized unit away from the furnace, the repairs can be solved easily. With the help of pulverized coal, the combustion takes place successfully.

12.What is FBC?. What are the advantages of a FBC?.
In fluidized bed combustion, rapid mixing ensures uniformity of temperature. The main advantage of fluidized bed combustion system is that municipal waste, sewage plant sludge, biomass, agricultural waste and other high moisture fuels can be used for heat generation.

13.What is the percentage of ash in Indian Coal?.
India's domestic coal reserves have a high ash content—up to 40 to 45 percent.

14.What is a high pressure boiler & what are their advantages.
A high pressure boiler is a shell and tube heat exchanger that use boiled water to create steam or high pressure hot water. 

Advantages of High-Pressure Boilers:
 These boilers require less floor space to install the setup. Forced Circulation of water is used in High-Pressure boilers which ensures positive circulation of fluid/water. The tendency of scale formation is minimized due to the high velocity of the water.

15.Name some high pressure boilers.
Types of High Pressure Boilers
La Mont Boiler
Benson Boiler
Loeffler Boiler
Velox Boiler
Cornish Boiler
Babcock and Wilcox Boiler

16.What it is reheat cycle? When reheating is used?
In a reheat cycle, the expansion takes place in two turbines. The steam expands in the high-pressure turbine to some intermediate pressure, then passes back to the boiler, where it is reheated at constant pressure to a temperature that is usually equal to the original superheat temperature.

17.What do you mean by regeneration cycle?
a cycle in a steam engine using heat that would ordinarily be lost: such as. a : a multiple-expansion steam-engine cycle in which the receivers are used as successive feed-water heaters.

18.What is Specific steam rate?
Specific Steam Consumption or Steam Rate (SSC) is the mass flow rate of steam required to produce 1 kW net work output.

19.What do you understand by cogeneration? When do we go in for Cogeneration power plants.
Cogeneration is a technique for producing heat and electricity in one process that can save considerable amounts of energy. Cogeneration is often associated with the combustion of fossil fuels but can also be carried out using some renewable energy sources and by burning wastes.

20.What do you mean by CHP?

abbreviation for. Combined Heat and Power: the production of both heat and electricity from the same device or power plant.

21.What are the advantages of condenser in a steam power plant?.
It decrease hotness of exhaust steam and thus additional work can be obtained. It enhance expansion ratio of steam and therefore raise efficiency of the plant. It decrease back pressure of steam and thus extra work can be obtain.

22.What are the main components of a condensing power plant?

Condenser chamber – where steam gets condensed.
Cooling water supply – which provides cold water to condense steam by heat exchanging.
Wet Air pumps – They collect condensed steam, the air and un-condensed water vapour and gases from condenser.

23.Name the types of condensers.
There are three main types: air-cooled, evaporative, and water-cooled condensers.

24.Define vacuum efficiency of a condenser.
Vacuum Efficiency in Condenser.

VACUUM EFFICIENCY : It is defined as the ratio of actual vacuum in condenser as recorded by the vacuum gauge to the ideal vacuum. Ideal pressure (pi) is that which corresponds with condensate temperature or with the temperature of steam entering the condenser

25.What is the function of cooling tower?
A cooling tower is a specialized heat exchanger in which air and water are brought into direct contact with each other in order to reduce the water's temperature. As this occurs, a small volume of water is evaporated, reducing the temperature of the water being circulated through the tower.

26.Name important gaseous pollutants discharged by thermal power plants.
A large portion (85%) of the total thermal power generation is through coal burning. On combustion of coal, pollutants generally emitted into the atmosphere are Sulphur dioxide (SO2), Oxides of Nitrogen (NOx) and Carbon Monoxide (CO) along with ash. Probably the most common pollutant emitted is Sulphur dioxide (SO2)

27.List the pollutants discharged by fossil fuel power plants

a) Diesel power plants

b) Gas turbine power plant

c) Nuclear power plants

d) List the harmful effects of Carbon monoxide, hydrocarbon, oxides of Nitrogen and soot on human health.

28.What do you understand by thermal pollution?
Thermal pollution is any deviation from the natural temperature in a habitat and can range from elevated temperatures associated with industrial cooling activities to discharges of cold water into streams below large impoundments.

29.What are the advantages and disadvantages of hydro power plants over other power plants?

30.What is runoff?
Runoff is the water that is pulled by gravity across land's surface, replenishing groundwater and surface water as it percolates into an aquifer or moves into a river, stream or watershed.

31.List the points which are used to select site for hydro power plants.
The most important thing is the availability of water. Soil type, Topography, Land use and land cover, slope, rainfall data, contour are the parameters required for selecting the suitable site. The selection of small hydropower plants can be done by using the satellite data and other data sources.

32.What is the function of Surge tank?
Surge tanks are used to measure liquid flow rate and the combined shrinkage and meter factor. They are also used as a second stage separator, and hold a constant back-pressure by using an automatic pressure control valve on the gas outlet. Surge tanks are also used for storage.

33.What is a pumped storage plant?
Pumped storage hydropower (PSH) is a type of hydroelectric energy storage. It is a configuration of two water reservoirs at different elevations that can generate power as water moves down from one to the other (discharge), passing through a turbine.

34.Name some nuclear power plants in India.
Kudankulam Nuclear Power Plant is the largest nuclear power station in India

Tarapur Atomic Power Station

35.What are the advantages of nuclear power plants?.

Nuclear Energy Pros
Low Cost of Operation. 
Reliable Source of Energy.
Stable Base Load Energy.
Produces Low Pollution.
Sufficient Fuel Availability.
It Has High Energy Density.
Expensive to Build.

36.What are the disadvantages of nuclear power plants?.

10 disadvantages of nuclear energy
  • It generates toxic nuclear waste.
  • It raises the chances of nuclear proliferation.
  • It is often targeted by terrorists.
  • It may lead to nuclear accidents.
  • It ups the risk of cancer.
  • It faces limitations due to nuclear fuel.
  • It is facing an acute shortage of sites.

37.State difference between nuclear fission and fusion.
Nuclear fission and fusion involve the disintegration and combination of the elemental nucleus. In the case of nuclear fission, an atom divides into two or more smaller or lighter atoms. Nuclear fusion occurs when two or more atoms join or fuse together to form a large or a heavier atom.

38.What are the main components of a nuclear power plant?

Components of a nuclear reactor
  • Fuel.
  • Moderator.
  • Control rods or blades.
  • Coolant.
  • Pressure vessel or pressure tubes.
  • Steam generator.
  • Containment.

39.What is the function of moderator & control rods?
Function of moderator is nuclear reactor—It slows down the speed of neutrons to make them useful for further fission.
Function on controlling rods is nuclear reactor—It absorbs the excess no. of neutrons which are produced in reactor.

40.Name the various types of nuclear power plant.
Main types of nuclear reactor
  • Pressurised water reactor (PWR)
  • Boiling water reactor (BWR)
  • Advanced gas-cooled reactor (AGR)
  • Light water graphite-moderated reactor (LWGR)
  • Fast neutron reactor (FNR) 
  • Operable nuclear power plants.

41.How do you classify gas turbine cycles?
Gas turbines are air-breathing, internal combustion heat engines. There are two types of gas turbine cycles: closed and open. Only open cycle gas turbine engine will be considered in this book, and the configurations that will be discussed are highlighted in Chart III.

42.Gas turbine plant operates on which thermodynamic cycle.
The basic thermodynamic cycle used in the gas turbine is the Brayton cycle

43.What are the criteria for selection of site for gas turbine power plant?
  • Availability of fuels : The fuels should be easily available at reasonably cheaper rates.
  • Transportation : Transportation facility be available.
  • Distance from the load center : To minimize losses and transmission line cost, the station shall be located near load center.

44.What are the environmental impact of gas turbine power plants?

Environmental Impacts of Natural Gas
  • Global warming emissions.
  • Air pollution.
  • Land use and wildlife.
  • Water use and pollution.
  • Earthquakes.
Thermal Power Plant
Hydro Electric Power Plant

Gas Turbine Power Plant
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