DIESEL POWER PLANT
Diesel power plants produce power from a diesel
engine. Diesel electric plants in the range of 2 to 50 MW capacities are used
as central stations for small electric supply networks and used as a standby to
hydro electric or thermal plants where continuous power supply is needed.
Diesel power plant is not economical compared to other power plants.
The diesel power plants are
cheaply used in the fields mentioned below.Peak load plants
1. Mobile electric plants
2. Standby units
3. Emergency power plants
4. Starting stations of
existing plants
5. Central power station etc.
General Layout of Diesel power plants
General
Layout of Diesel power plants
Figure shows the arrangements of the engine and its
auxiliaries in a diesel power plant. The major components of the plant are:
a) Engine
Engine is the heart of a diesel power plant. Engine is
directly connected through a gear box to the generator. Generally two-stroke
engines are used for power generation. Now a days, advanced super & turbo
charged high speed engines are available for power production.
b) Air supply
system
Air inlet is arranged outside the engine room. Air from the
atmosphere is filtered by air filter and conveyed to the inlet manifold of
engine. In large plants supercharger/turbocharger is used for increasing the
pressure of input air which increases the power output.
c) Exhaust System
This includes the silencers and connecting ducts. The heat
content of the exhaust gas is utilized in a turbine in a turbocharger to
compress the air input to the engine.
d) Fuel System
Fuel is stored in a tank from where it flows to the fuel pump
through a filter. Fuel is injected to the engine as per the load requirement.
e) Cooling system
This system includes water circulating pumps, cooling towers,
water filter etc. Cooling water is circulated through the engine block to keep
the temperature of the engine in the safe range.
f) Lubricating system
Lubrication system includes the air pumps, oil tanks,
filters, coolers and pipe lines. Lubricant is given to reduce friction of
moving parts and reduce the wear and tear of the engine parts.
g) Starting SystemThere are three commonly used starting systems, they are;
1) A petrol driven auxiliary engine,
2) Use of electric motors,
3)Use of compressed air from an air compressor at a pressure of 20 Kg/cm”
h) Governing system
The function of a governing system is to maintain the speed
of the engine constant irrespective of load on the plant. This is done by
varying fuel supply to the engine according to load.
Advantages of diesel power
plants
1. More efficient than
thermal plant
2. Design, Layout etc are
simple and cheap
3. Part load efficiency is
very high
4. It can be started quickly
5. Simple & easy
maintenance
6. No problem with fuel &
dust handling
7. It can be located in the
heart of town
8. Less cooling water
required.
Disadvantages
1. There is a limitation for
size of a diesel engine
2. Life of plant is
comparatively less
3. Noise pollution is very
high
4. Repair cost is very high
5. High lubrication cost
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