Power Plant Engineering Set 1

Answer: 35 to 45%

Explaination:
efficiency of rankine cycle in actual working condition is found to be between 35 to 45%.

Answer: 27.7

Explaination:
fixing the states; h1 = 340.5 kj/kg, h2 = h1 + v1 (p2 – p1) = 343.5 kj/kg, h3 = 3115.3 kj/kg, s3 = 6.7428 kj/kg – k, x4

Answer: depending tubular heating surface

Explaination:
based on the contents of the tubular heating surface, boilers are primarily classified as fire tube boiler and water tube boiler. fire tube boilers those in which production of combustion pass through the tubes and water tube boilers are those in which the products of combustion surround the water tubes from outside.

Answer: fire tube boiler

Explaination:
cornish boiler is an example of fire tube boiler and also includes cochran, lancashire, and locomotive and scotch marine boilers. fire tube boilers are those in which the products of combustion pass through the tubes and water lies around the outside of tubes. these boilers operate at moderate pressure (16-20bar) and more suitable to generate 3-8 tons of steam per hour which is used in process heating.

Answer: water tube boiler

Explaination:
water tube boilers are those in which the products of combustion (hot flue gas) surround the water tubes from outside. cold water enters the tubes and leaves hot. these boilers operate at very high pressures and are used for power generation.

Answer: babcock-wilcox boiler

Explaination:
if the boilers are used at one place only they are termed as stationary boilers. these boilers are used for either process heating in industries or for power generation in steam power plants. these are used at central station utility power plants, for plant process etc. ex: babcock-wilcox boiler, fluidized bed combustion (fbc) boiler.

Answer: locomotive boiler

Explaination:
the boilers, if they are portable, i.e., if they can be moved from one place to other place those are known as mobile boilers. such boilers are used in locomotives and ships to get the engine moving. and also small units are used for temporary at working sites. ex: locomotive boiler, marine boiler etc.

Answer: yes

Explaination:
boilers can be classified based on fuel used for combustion or heat generation source. various heat sources are: heat generated by the combustion of fuel in solid, liquid or gaseous form. heat generated by hot waste gases as byproducts of other chemical processes. heat generated by electrical energy and nuclear energy.

Answer: 180bar

Explaination:
water is purely circulated by density difference with most of the heat from the fuel flame being radiated to the water walls directly. the steam pressure of such boilers is limited to about 180bar, with water and steam being separated in the boiler drum.

Answer: once-through boilers

Explaination:
once-through boilers operate above critical pressure i.e., above 221.2bar. as the density of water and steam are same above the critical pressure there will be no recirculation. these types of boilers are also called as positive forced circulation boilers.

Answer: positive forced circulation boiler

Explaination:
in positive forced boilers, water enters the bottom of the tubes and completely transforms into steam as it passes through the tubes and reaches at the top. thus, these boilers do not need a steam drum and hence often referred as drum-less boilers. these boilers work at very high pressures.

Answer: high working pressure

Explaination:
due to high working pressure and positive circulation of water, chances of sediments depositing inside water tubes in the shell is less. this high working pressure of boiler in the shell can withstand high temperature or thermal stresses.

Answer: water circulation is limited inside boiler shell

Explaination:
water circulation is limited inside the boiler shell. water need not be that much pure and needs minimum treatment like passing through a pressure filter. cleaning

Answer: reheating cycles

Explaination:
to obtain a gain in thermal cycle efficiency, apart from the feedheating, there should be multiple number of reheats.

Answer: double reheat

Explaination:
incorporating double reheat is one way to prevent the low pressure turbine exhaust wetness from being excessive.

Answer: 221.2 bar

Explaination:
steam generation in a “once through” boiler is at the critical point of 221.2 bar.

Answer: 238 degree centigrade

Explaination:
in a typical layout of a 215mw

Answer: drain cooler

Explaination:
the input to the low pressure feedwater heater comes from the drain cooler which goes to the deaerator.

Answer: nuclear power plant

Explaination:
demand of electrical energy is increasing at fast rate owing to booming increase in the population and industrial growth. the reserves of fossil fuel i.e., coal, oil and gas are fast depleting. there are many alternative sources of energy but they are not enough to supply such huge demand, only

Answer: 3000 tonnes of high grade coal

Explaination:
one of the main attention for nuclear fuel is the huge amount of energy that can be released from a small quantity of active nuclear fuel. the energy obtainable by

Answer: more than 5 years

Explaination:
very small amount of nuclear fuel can produce very high amount of energy. nuclear fuel may remain in a reactor for more than 5 years.

Answer: capital cost

Explaination:
nuclear fuel in a nuclear reactor may remain for more than 5 years. so the cost of fuel injected initially is taken as capital cost and may be a few crore rupees.

Answer: taxes and insurance

Explaination:
taxes and insurance are taken as fixed costs. salaries and wages of operation and maintenance staff, cost of waste disposal and cost of processing materials are the operation and maintenance cost.

Answer: 30 to 40 %

Explaination:
the overall efficiency of a nuclear power plant is around 30 to 40%. efficiency is higher at high road factors. therefore, a nuclear power plant is always operated as a base load plant.

Answer: equel to thermal power plant

Explaination:
nuclear power plants need less area as compared to any other plant of same generation capacity. a 2000mw nuclear power plant needs about 80 acres whereas the coal fired steam power plant of same generation capacity needs 250 acres of land.