1. Internship Report
Page 1 of 9
Jamshoro Power Company Limited, Jamshoro
Internship Report
By
Mahmood Ali Korai
(12EL92)

2. Internship Report
Page 2 of 9
Jamshoro Power Company Limited, Jamshoro
Introduction To Power Generating Station:
Power House also known as Power Station is a place where electricity is produced. Power House
can be classified on the basis of the source from which the electricity is produced i.e. The Hydro
Power Plant (in which the electricity is produced for the water stored by dam), Thermal Power
Plant (in which the electricity is produced from the heat which is produced from of combustion
fossil fuel, garbage or by using geothermal energy, and biomass), Solar Power Plant (in which the
electricity is produced by striking of sunlight on photovoltaic cell), Windmill Power (in which the
electricity is produced by wind) and Nuclear Power Plant (in which the electricity is produced
from nuclear fission).
In each type of power plant, the way of producing electricity is different and their cost of
installation, operational, and maintenance cost also vary. Electricity is produced by hydro power
plant is the cheapest and the electricity which is produced by thermal power station (burning
fossil fuel) is very costly.
Such a type of power plant is installed in an area where availability of resource is available. In
simple words, you cannot install a windmill power where is no wind. There is a great abundance
of water in northern areas of Pakistan, so hydro power plants are installed and in southern areas
of Pakistan, only thermal power stations are installed namely HUBCO, Hub; GUDDU Power Plant,
Guddu; JPCL, Jamshoro; GTPS Kotri and also Bin Qasim Power Plant, Karachi which is owned by
KESC (Karachi Electric Supply Company) now known as K-Electric (Karachi Electric). It must also
be noted that thermal power stations are not only installed in southern areas but all over
Pakistan.
Thermal power station are usually located near a river or lake because large quantity of cooling
water is needed to condense steam as it exhausts from turbines. Therefore Thermal Power
Station Jamshoro is also located near to the right bank of Indus River. The Power Station comprises
of four units having total capacity of 850 MW. Unit No.1; 250 MW is installed by Mitsui Ship Holding Co.
Japan only runs on HSD (High Speed Diesel) oil, whereas Units 2, 3 and 4 of 200 MW are installed by a
Chinese company each are dual fuel i.e. Gas/HSD oil.

3. Internship Report
Page 3 of 9
Jamshoro Power Company Limited, Jamshoro
The efficiency of thermal generating station is very low because of the inherent of low efficiency
of turbines. The maximum efficiency of any turbine that converts heat energy into mechanical
energy is given by the equation
ŋ = 1 −
2
1
× 100
where
ŋ = efficiency of the machine
T1 = Temperature of the gas entering the turbine [K]
T2 = Temperature of the gas leaving turbine [K]
In thermal power station the gas is steam quotient T2/T1 should be small as possible. However
temperature cannot be lower than ambient temperature, which is usually about 20 oC. As a result
T2 cannot be less than
2 = 273 + 20 = 293
This means that to obtain higher efficiencies, T2 should be as high as possible. The problem is
that we cannot use temperature above those steel and other metals can safely withstand,
bearing in mind the corresponding high steam pressure. It turns out that the highest feasible
temperature T1 about 550 oC or 540 oC. As a result
1 = 550 + 273 = 823
It follows that the maximum possible efficiency of a turbine can be given as at different
temperatures;
T1 = 293:293+25;
T2 = 273 + 540;
efficiency = (1-(T1./T2))*100;
[T1' efficiency']
Temperature Efficiency
293.0000 63.9606
294.0000 63.8376
295.0000 63.7146
296.0000 63.5916
297.0000 63.4686
298.0000 63.3456
299.0000 63.2226
300.0000 63.0996
301.0000 62.9766
302.0000 62.8536
303.0000 62.7306
304.0000 62.6076
305.0000 62.4846
306.0000 62.3616

4. Internship Report
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Jamshoro Power Company Limited, Jamshoro
307.0000 62.2386
308.0000 62.1156
309.0000 61.9926
310.0000 61.8696
311.0000 61.7466
312.0000 61.6236
313.0000 61.5006
314.0000 61.3776
315.0000 61.2546
316.0000 61.1316
317.0000 61.0086
318.0000 60.8856
Due to other losses, some of the most efficient steam turbines have efficiencies of 35 %. This means that
the 65 % of thermal energy is lost during the thermal to mechanical conversion process. The enormous
loss of heat and how to dispose of it represents one of the major aspect of a thermal generating station.
With the combined cycle, the efficiency of power plant can be improved up to 75-85 %.In combined
cycle power plants (CCPPs) a gas turbine generator generates electricity while the waste heat from the
gas turbine is used to make steam to generate additional electricity via a steam turbine.
In other words: The output heat of the gas turbine flue gas is utilized to generate steam by passing it
through a heat recovery steam generator (HRSG), so it can be used as input heat to the steam turbine
power plant. This combination of two power generation cycles enhances the efficiency of the plant. While
the electrical efficiency of a simple cycle plant power plant without waste heat utilization typically ranges
between 25% and 40%, a CCPP can achieve electrical efficiencies of 60% and more. Supplementary firing
further enhances the overall efficiency.

5. Internship Report
Page 5 of 9
Jamshoro Power Company Limited, Jamshoro
Makeup of a Thermal Generating Station
Pumping Plant:
As the name suggests, the job of pumping plant is to pump the water from one place to another. It usually
pumps water from river or lake for thermal generating station. A thermal generating station needs a huge
amount of water to produce the steam and to condense it after striking on turbine. In Jamshoro Power
House, water is pumped from Indus River with the help of heavy duty motors to pump water.
Water Treatment Plant:
After pumping plant, water goes to water treatment plant where it is filtered and all its impurities are
removed. The boiling point of water contacting impurity is higher than distilled water i.e. 100 o
C. The
boiling point of impure water may rise to 102 o
C and melting point of water may decrease to -2 o
C. So, it’s
clear if boiling of water will increase, we will have to use more energy (more fuel we will have to burn) to
convert the water into steam. Because of impurities, they can also corrode the pipes, turbine and other
equipment and will also reduce their life and hence of power plant. The ph of water is kept a little greater
than 7.0 which is the neutral point. It means that water is kept basic.
 After filtration plant, water goes to boiler [1] or steam generator. There are many types of boiler.
Water tube boiler is very commonly used. Boiler acts as furnace, transferring heat from burning
fuel to row upon row of water tubes S1, which entirely surround the flames. Water is kept
circulating through tubes by a pump P1.

6. Internship Report
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Jamshoro Power Company Limited, Jamshoro
 A drum [2] containing water and steam. Under high pressure produces the steam required by the
turbines. The pressure is kept high because at low pressure boiling point of water decreases and
at high pressure boiling point of water increases. It also receives the water delivered by boiler
feed pump P3. Steam races towards HP (high pressure) turbine after having passed through
superheater S2. The superheater composed of a series of tubes surrounding the flames, raise the
steam temperature about 200 o
C. This increase in temperature ensure that steam is absolutely
dry and raise the overall efficiency of the station.
 The low, medium, and high pressure turbine possess a series of blades mounted in the driver
shaft. The steam is deflected by the blades, producing a powerful torque. These blades are made
of special steel to withstand the high temperature and intense centrifugal forces. The HP, MP, and
LP turbines are coupled together to drive a common generator. In Jamshoro Power House, HP
turbines drive one generator while MP and LP drive two different generator. A HP turbine [3]
converts thermal energy into mechanical energy by letting the steam expand as it moves through
turbine blades. The temperature and pressure at the output of the turbine, therefore, less than
at the input. In order to raise thermal efficiency and to prevent permanent condensation, the
steam passes through a reheater S3, composed of a third set of heated tubes.
 The MP (medium pressure) turbine or IP (Intermediate pressure) turbine [4] is similar to the high
pressure turbine, except that it is bigger that the steam may expand still more.
 The LP (low pressure) turbine [5] is composed of two identical left hand and right hand sections.
The turbine sections remove the remaining available energy from the steam. The figure of LP
turbine is given below;
The steam flowing out of LP expands into an almost perfect vacuum created by the condenser.
 The condenser [6] causes the steam to condense by letting it flow over cooling pipes S4. Cold water
from an outside source, such as filtration plant, flows through the pipes, thus carrying away the
heat. It is the condensing steam that creates the vacuum.

7. Internship Report
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Jamshoro Power Company Limited, Jamshoro
 A condensate pump P2 removes the lukewarm condensate steam and drives it through a reheater
[7] towards a feedwater pump [8].
 The reheater [7] is a heat exchanger. It receives the hot steam, bled off from HP turbine, to raise
the temperature of feed water.
 The burners [9] supply and control the amount of gas, oil or coal injected into the boiler. Heavy
bunker oil is preheated and injected as an atomized jet to improve the surface contact (and
combustion) with surrounding air.
 A FDF [10] (forced draft fan) furnishes the enormous quantities of air needed for combustion.
 An IDF [11] (induced draft fan) carries gases and other products of combustion toward cleansing
apparatus and from there to the stack and the outside air.
 Generator G, mechanically coupled with all turbines, convert the mechanical energy into electrical
energy.
There is also two other equipment that are not shown in figure is i.e. de-aerator and economizer.
Deaerator
Deaerator is used to remove the dissolved oxygen as well as other non-condensable gases from feedwater
which can react with metallic equipment and form oxides. Consequently it will corrode them and reduce
the life of a power station. Dissolved carbon dioxide combines with water to form carbonic acid that
causes further corrosion. Most deaerators are designed to remove oxygen down to levels of 7 ppb by
weight (0.005 cm³/L) or less as well as essentially eliminating carbon dioxide.
There are two basic types of deaerators, the tray-type and the spray-type.

8. Internship Report
Page 8 of 9
Jamshoro Power Company Limited, Jamshoro
 The tray-type (also called the cascade-type) includes a vertical domed deaeration section
mounted on top of a horizontal cylindrical vessel which serves as the deaerated boiler
feedwater storage tank.
 The spray-type consists only of a horizontal (or vertical) cylindrical vessel which serves as both
the deaeration section and the boiler feedwater storage tank.
Economizer:
An economiser is a mechanical device which is used as a heat exchanger by preheating a fluid to reduce
energy consumption. In a steam boiler, it is a heat ex-changer device that heats up fluids or recovers
residual heat from the combustion product i.e. flue gases in thermal power plant before being released
through the chimney. Flue gases are the combustion exhaust gases produced at power plants consist of
mostly nitrogen, carbon dioxide, water vapour, soot carbon monoxide etc.
Cooling Tower:
The Jamshoro Power House is located far away from Indus River. When steam comes from turbine, then
it is condensed by condenser. Hence, the temperature of condenser increases. So, we will have to cool
condenser, on way or another. In the case of thermal generating station, the warm cooling water flowing
out of the condenser is pipes to the top of a cooling tower where it is broken into small droplets. As the
droplets fall towards upon reservoir below, evaporation takes place and the droplets are chilled. The cool
water is pumped from the reservoir and recirculated through the condenser, where it again removes heat
from condensing steam. The cycle then repeats. Approximately 2 % of the cooling water that flows
through the condenser is lost by evaporation. This loss can be made up by Indus River.
Thermal Power Station and the Environment:
The products of combustion of thermal generating station are an interesting subject of concern, due to
their impact on the environment. Carbon dioxide, sulfur dioxide, and water are the main products of
combustion when oil, gas or coil are burned. Carbon dioxide and water produce no immediate
environmental effects, but sulfur dioxide creates substance that give rise to acid rain. Dust and fly ash are
other pollutants that may reach the atmosphere. Natural gas produces only water and carbon dioxide.
This explains, why gas is used rather than (oil or coal), when atmospheric pollution must be reduced to
minimum. But, the carbon dioxide is a greenhouse which is playing an active role in global warming and
increasing the temperature of earth atmosphere. Because of global warming, glaciers are melting
dramatically and raising the sea level and causing flood in the rivers.

9. Internship Report
Page 9 of 9
Jamshoro Power Company Limited, Jamshoro
Here is the data of a power plant for the better understanding of a power generating station that how it
works. This data may vary from one generating station to another.
Electrical Data
Number of generator: 4
Power per generator: 660 MW
Speed: 3000 rev/min
Voltage: 23,000 V
Frequency: 50 Hzphase: 3
Mechanical Data
Number of steam turbines: 4
Number of condensers: 4
Number of boilers: 4
Steam flow per turbine: 560 kg/s
Steam temperature: 540 o
C
Steam pressure: 16.55 MPa
Cooling water per condenser: 21,000 kg/s
Coal consumption per boiler: 51.5 kg/s
Dust capture by cleaning system: 28 kg/s