Diesel engine power plant

1. DIESEL ENGINE POWER
PLANT
PREPARED BY
• SOHAIL ALI AZAD - 113250
• ABDUL MUQEET – 113231
• ISHTIAQUE AHMED - 113217

2. • A Generating station in which diesel engine is used
as prime mover for generation of electrical energy
is known as diesel power station .
• Diesel power plant produce power in the range of 2
– 50 MW .
• Diesel Power stations are favored where demand of
power is less sufficient quantity of coal and water is
not available
• They are used as standby set for continuity of
supply such as hospitals, radio stations, cinema
theatres, etc.
INTRODUCTION

3. ADVANTAGES
• The design and layout of the plant are quiet simple.
• It occupies less space.
• It can be located at any place.
• It can be started quickly and can pick up load in a short time.
• It requires less quantity of water for cooling.
• The overall cost is much less than that of steam power plant of same capacity.
• The thermal efficiency of the plant is higher.
• It requires less operating staff.

4. DISADVANTAGES
• The plant has higher running costs as the fuel that is used is costly.
• The plant does not work satisfactory under overload conditions for a longer
period.
• The plant can only generate small power.
• The cost o lubrication is generally high.
• The maintenance cost is also high.

5. APPLICATIONS
• They are used as central stations for small power supplies.
• They can be used as standby plants to hydrodynami8c plants and steam
power plants In case of an emergency.
• They can be used as peak load plants in combination with thermal or hydro
plants.
• They are quiet suitable for mobile power generations and are widely used
in transportation systems such as automobile, railways, ships.

6. GENERAL LAYOUT

7. GENERAL LAYOUT

8. ESSENTIAL ELEMENTS OF DIESEL POWER PLANT
• Starting system
• Air Intake System
• Fuel supply system
• Exhaust system
• Cooling system
• Lubrication system
• Governing system

9. STARTING SYSTEM
• The function of this system is to start the engine from cold by supplying
compressed air at about 17 bar from an air tank that is admitted into few
cylinders making them work like reciprocating air motors to run the engine
shaft
• Fuel is then injected into remaining cylinders and ignited in the normal way
causing the engine to start

10. ENGINE SYSTEM
• Generally classified as Two stroke engines and 4 stroke engines.
• In diesel engine air is admitted into the cylinder and is compressed.
• At the end of the compression stroke fuel is injected.
• The burning gases expand and does work on the piston.
• The gases are then exhausted from the cylinder.

11. AIR INTAKE SYSTEM
• The air intake system conveys fresh air through pipes or ducts to (i) the air
intake manifold (ii) the supercharger inlet of a supercharged engine.
• Air filter is used to remove the dust from air which is taken by the engine.
• The super charger is used to increase the pressure of air supplied.
• Air is firest drawn thru the filter to catch dirt particles that may cause
excessive wear in cylinders.
• Filters may be of two types
• Dry type (paper, cloth etc.)
• Wet type (oil impingement type where oil helps to catch particles )

12. FUEL SUPPLY SYSTEM
• It includes storage tank, fuel pump, fuel transfer pump, strainers and
heaters.
• Pump draws diesel from storage tank through the filter to day tank.
• The day tank is usually placed high so the diesel flows to engine under
gravity.
• Diesel is filtered before being injected into the engine by the fuel injection
pump.

13. FUEL SUPPLY SYSTEM
This Sytem performs the following function
• Filter the fuel.
• Meter the correct quantity of the fuel to be injected.
• Time the injection process.
• Regulate the fuel supply.
• Distribute the atomized fuel properly in the combustion chamber.

14. EXHAUST SYSTEM
• This includes the silencers and connecting ducts.
• The exhaust gases coming out of the engine is noisy.
• Silencer is provided to reduce the noise.
• Exhaust pipe leading out of the building in should be short in length with minimum
number of bends to provide as low a pressure loss as possible.
• Each engine should have its independent exhaust system.
• Where possible exhaust heat recovery should be made to improve plant thermal efficiency.
Eg. Air heating, steam generation in diesel steam power plant etc.

15. EXHAUST SYSTEM

17. COOLING SYSTEM
• The cooling system consists of a water source, pump and cooling towers. The pump
circulates water through cylinder and head jacket. The water takes away heat form
the engine and it becomes hot. The hot water is cooled by cooling towers and re
circulated for cooling.
• The temperature of the burning fuel inside the engine cylinder is in the order of
2750deg Celsius. In order to lower this temperature water is circulated around the
engine.
• The water envelopes(water jacket) the engine. The heat from the cylinder, piston,
combustion chamber etc., is carried by the circulating water.
• The hot water leaving the jacket is passed through the heat exchanger
• The heat from the heat exchanger is carried away by the raw water circulated through
the heat exchanger and is cooled in the cooling system

18. COOLING SYSTEM

19. COOLING SYSTEM
There are two methods of cooling I.C. engines:
1.Air cooling.
2. Liquid cooling

20. COOLING SYSTEM
Air cooling:
• In this method, heat is carried away by
the air flowing over and around the
cylinder.
• Fins are added on the cylinder which
provide additional mass of material for
conduction as well as additional area for
convection and radiation modes of heat
transfer

21. COOLING SYSTEM
Liquid cooling:
• In this method, the cylinder walls and
head are provided with jackets through
which the cooling liquid can circulate.
• The heat is transferred from the cylinder
walls to the liquid by convection and
conduction.
• The liquid gets heated during its passage
through the cooling jackets and is itself
cooled by means of an air cooled
radiator system.

22. LUBRICATION SYSTEM
• It includes the oil pumps, oil tanks, filters, coolers and connecting pipes.
• The purpose of the lubrication system is to reduce the wear of the
engine moving parts
• Part of the cylinder such as piston , shafts , valves must be lubricated.
The lubricant is cooled before recirculation.
• Lubrication also helps to cool the engine.

23. LUBRICATION SYSTEM
The following are the important functions of a lubrication system:
• LUBRICATION: To keep parts sliding freely past each other, reducing friction and wear.
• COOLING: To keep surfaces cool by taking away part of the heat caused by friction.
• CLEANING: To keep the bearings and piston rings clean.
• SEALING: To form a good seal B/W the piston rings and cylinder walls.
• REDUCING NOISE: to reduce the noise of the engine by absorbing vibration.

24. GOVERNING SYSTEM
• The function of the governing
system is to maintain the speed
of the engine
• This is done generally by varying
fuel supply to the engine
according to load.
• It is achieved with use of
governors.

25. Supercharging:
The apparatus used to increase the air density is called supercharger. It is similar to a
compressor(centrifugal type), which provides greater mass of charge with same piston
displacement.
• The purpose of supercharging is to raise the volumetric efficiency above that value which can
be obtained by normal aspiration.
• The engine is an air pump, increasing the air consumption permits greater quantity of fuel to
be added, and results in greater potential output.
• The power output is almost directly proportional to the air consumption.

26. Supercharging:
Three methods to increase the air consumption are
1. Increasing the piston displacement: leads to more size and weight, cooling problems
2. Running the engine at higher speeds leads to mechanical wear and tear.
3. Increasing the density of the charge, so that greater mass of charge is introduced in same
volume.
The supercharger produces following effects:
1. Provides better mixing of air fuel mixture due to turbulent effect of supercharger.
2. The temperature of charge is raised as it is compressed, resulting in higher temperature
within the cylinder, so better vaporization of fuel.
3. Power required to run the supercharger is obtained from engine