(SEM VIII) THEORY EXAMINATION 2017-18 POWER PLANT ENGINEERING

Here is your Power Plant Engineering (NME801) – Section A, B and C in brief, clear paragraph format (not too long, exam-ready style) based on your uploaded paper 

POWER-PLANT-ENGINEERING-NME801-1

SECTION A (Brief Explanations)
 

Load Factor and Cost per kWh
Load factor is the ratio of average load to maximum load over a period. A higher load factor means the plant operates near its rated capacity for longer time, which reduces cost per kWh because fixed costs are distributed over more energy units.

Plant Use Factor
Plant use factor is the ratio of energy generated to the product of plant capacity and number of hours the plant was actually in operation. It indicates how effectively the plant capacity is utilized.

Overfeed vs Underfeed Stokers
In overfeed stokers, coal is fed from the top of the grate and burns while moving downward. In underfeed stokers, coal is supplied from below and air passes upward through the fuel bed. Underfeed stokers provide better combustion efficiency.

Purpose of Governing in Steam Turbine
Governing controls the speed of the turbine when load changes. It ensures constant speed and frequency of power supply. Methods include throttle governing, nozzle governing, and by-pass governing.

Wet Sump vs Dry Sump Lubrication
In wet sump lubrication, oil is stored in the crankcase. In dry sump lubrication, oil is stored in a separate tank and pumped to the engine. Dry sump systems provide better lubrication and cooling.

Gas Turbine vs Diesel Cycle Temperature
Gas turbine maximum temperature is limited due to material constraints and blade cooling requirements, whereas diesel engines operate at higher peak temperatures due to intermittent combustion.

Chemical Energy vs Nuclear Energy
Chemical energy is released through chemical reactions like combustion. Nuclear energy is released from nuclear fission or fusion reactions and produces much higher energy per unit mass.

Thermal Neutron
A thermal neutron is a slow-moving neutron with low kinetic energy. It is effective in sustaining nuclear chain reactions.

Runoff
Runoff is the portion of rainfall that flows over land into rivers and reservoirs. It is important in hydro power generation.

Pollution from Power Generation
Power plants cause air pollution (CO₂, SO₂, NOx), water pollution, thermal pollution, and noise pollution.

SECTION B (Medium Length, Clear Explanation)

Incremental Heat Rate and Economic Scheduling
Incremental heat rate represents the increase in heat input required for producing an additional unit of electricity. Economic scheduling distributes load among generating units so that total operating cost is minimized. The principle states that load should be shared such that incremental cost of all units is equal.

La Mont Boiler
La Mont boiler is a high-pressure water tube boiler. It uses forced circulation of water through small diameter tubes by a pump. Water is heated rapidly and converted into steam. It has high efficiency and quick steam generation capability.

Components of Diesel Power Plant
A diesel power plant consists of diesel engine, fuel system, lubrication system, cooling system, air intake system, and generator. The diesel engine converts fuel energy into mechanical energy, which drives the generator to produce electricity.

Site Selection of Hydro Power Plant
The site should have adequate water supply, sufficient head, good geological conditions, accessibility, and minimal environmental impact. Proper site selection ensures efficient and economical power generation.

SECTION C (10-Mark Style Answers)

Depreciation and Sinking Fund Method
Depreciation is the reduction in value of equipment over time due to wear and tear. In the sinking fund method, a fixed amount is set aside annually and invested at compound interest so that the total amount equals replacement cost at the end of equipment life.

Load Curve and Load Factor
A load curve shows variation of load with time. Load duration curve rearranges load in descending order. Load factor is calculated as average load divided by maximum load. Higher load factor indicates better plant utilization.

Feed Water Treatment and DM Plant
Feed water treatment removes impurities to prevent scaling and corrosion in boilers. A DM (Demineralization) plant removes dissolved salts using ion exchange resins. It improves boiler efficiency and life.

Fluidized Bed Combustion (FBC)
In FBC, solid fuel particles are suspended in air stream, creating fluid-like behavior. It ensures uniform temperature and efficient combustion. It reduces pollution and improves efficiency compared to conventional combustion.

CANDU Nuclear Power Plant
CANDU reactor uses heavy water as moderator and coolant and natural uranium as fuel. It allows online refueling and high efficiency. It has good neutron economy but requires heavy water which is expensive.

Hydro Power Reservoir and Output
Reservoir capacity depends on seasonal water flow variation. Output power is calculated using head, discharge, efficiency, and gravity constant. Higher head and discharge produce higher power.

Generator Construction and Cooling
A generator consists of stator, rotor, field winding, and cooling system. Cooling is necessary to remove heat generated due to electrical losses and maintain efficiency.

Bus-Bar Arrangements
Ring bus-bar and bridging bus-bar arrangements improve reliability of power distribution. They allow maintenance without interrupting supply.