steam plant
Post on 03-Jun-2018
248 Views
Preview:
TRANSCRIPT
-
8/12/2019 STEAM PLANT
1/102
steam power plant
BABA HIRA SINGH BHATTAL INSTITUTE OF
ENGINEERING AND TECHNOLOGY LEHRAGAGA-
148031 DISTT.SANGRUR (Pb.)
By :-Rakesh kumar
Assistant professor
Electrical Engineering Department.
-
8/12/2019 STEAM PLANT
2/102
Essentials of Steam Power Plant Equipment
A steam power plant must have following equipment :
(a) A furnace to burn the fuel.
(b) Steam generator or boiler containing water. Heat
generated in the furnace is utilized to convert water into
steam.(c) Main power unit such as an engine or turbine to use the
heat energy of steam and perform work.
(d) Piping system to convey steam and water.
-
8/12/2019 STEAM PLANT
3/102
The flow sheet of a thermal power plant consists of the
following four main cir cui ts :(a) Feed water and steam flow circuit.
(b) Coal and ash circuit.
(c) Air and gas circuit.
(d) Cooling water circuit.
-
8/12/2019 STEAM PLANT
4/102
A steam power plant using steam as working
substance works basically on Rankine cycle.
Steam is generated in a boiler, expanded in theprime mover and condensed in the condenser and
fed into the boiler again.
-
8/12/2019 STEAM PLANT
5/102
-
8/12/2019 STEAM PLANT
6/102
Types of steam Generators Horizontal vertical or inclined.
Fire tube or water tube.
Externally fired or internally fired.
Forced circulation and natural circulation.
High pressure or low pressure boiler.
-
8/12/2019 STEAM PLANT
7/102
Daltons law The partial pressure pressure of each
constituent is that pressure which the gas
would exert if it occupied alone that volumeoccupied by the mixture at the sametemperature.
-
8/12/2019 STEAM PLANT
8/102
Factors that should be considered while
selecting the boiler Working pressure and quality of steam
required.
Steam generation rate.
Floor area available.
The portable load factor.
Erection facilities.
-
8/12/2019 STEAM PLANT
9/102
Properties of good steam generators It should be absolutely reliable.
It should occupy minimum space.
It should be light in weight.
Capable of quick starting.
Erection of boiler should be simple.
-
8/12/2019 STEAM PLANT
10/102
Steam Power Plants are Classified as1. By fuel.
2. By prime mover.
3. By cooling tower.
-
8/12/2019 STEAM PLANT
11/102
Steam Power Plants are also Classified as;
Central stations; the electrical energy available fromthese stations is meant for sale to the consumers who
wish to purchase it.
I ndustr ial/ captive power stations; this type of
power station is run by the manufacturing company for
its own use and its output is not available for general
sale.
-
8/12/2019 STEAM PLANT
12/102
Jet condenser; low manufacturing cost. Low
upkeeps, requires small floor space and more
auxiliary power required.
surface condenser; high manufacturing cost. high
upkeeps, requires large floor space and less
auxiliary power required.
-
8/12/2019 STEAM PLANT
13/102
Feed water heating improves overall plant
efficiency.
Quantity of steam produced by the boiler isincrease.
Thermal stress due to cold water entering the boiler
drum are avoided.Chance of boiler corrosion are decrease.
-
8/12/2019 STEAM PLANT
14/102
dust collectorsare Classified as;
Mechanical dust collectors;
(a)Wet type(scrubbers)
Spray type, packed type and impingement type.
(b) dry type
Gravitational separators, cyclone separators,
electricaldust collectors;Rod type and plate type.
-
8/12/2019 STEAM PLANT
15/102
DIFFERENT TYPES OF BOILERS USED IN
STEAM POWER PLANTS
horizontal, vertical or inclined.
fire tube and water tube .
Externally or internally fired.
Forced or natural circulation.
High pressure or low pressure.
Stationary or portable.
Single-tube and multi-tube.
-
8/12/2019 STEAM PLANT
16/102
or ng agram ermapower station.
S T bi P Pl
-
8/12/2019 STEAM PLANT
17/102
C
saturatedwater
hot gases
SteamTurbine
Gen
compressedwater
superheatedsteam
Condenser
Pump
cooling watersaturatedsteam
Steam Generator(Boiler / Furnace)
Steam Turbine Power Plant
-
8/12/2019 STEAM PLANT
18/102
Schematic arrangement of equipment of a
steam power station.Coal received in coal storage yard of power
station is transferred in the furnace by coal
handling unit. Heat produced due to burning ofcoal is utilized in converting water contained in
boiler drum into steam at suitable pressure and
temperature. The steam generated is passedthrough the superheater.
-
8/12/2019 STEAM PLANT
19/102
Superheated steam then flows through the
turbine. After doing work in the turbine the
pressure of steam is reduced. Steam leaving theturbine passes through the condenser which is
maintained the low pressure of steam at the
exhaust of turbine.
-
8/12/2019 STEAM PLANT
20/102
Steam pressure in the condenser depends upon flowrate and temperature of cooling water and oneffectiveness of air removal equipment. Watercirculating through the condenser may be taken
from the various sources such as river, lake or sea. Ifsufficient quantity of water is not available the hotwater coming out of the condenser may be cooled incooling towers and circulated again through the
condenser. Bled steam taken from the turbine atsuitable extraction points is sent to low pressure andhigh pressure water heaters.
-
8/12/2019 STEAM PLANT
21/102
Air taken from the atmosphere is first passed
through the air pre-heater, where it is heated by
flue gases. The hot air then passes through thefurnace. The flue gases after passing over
boiler and superheater tubes, flow through the
dust collector and then through economiser, airpre-heater and finally they are exhausted to the
atmosphere through the chimney.
-
8/12/2019 STEAM PLANT
22/102
Disadvantage of steam power plant
Maintenance and operating cost are high.
Long time required for erection and putting into
action . Large quantity of water is required.
Great difficulty experienced in coal handling .
Efficiency decreases rapidly below about 75 percentload.
-
8/12/2019 STEAM PLANT
23/102
Advantages relating the steam in high pressure
steam plantTo maintain equal distribution of steam.
To maintain speed of steam turbine.
To maintain proper temperature.
-
8/12/2019 STEAM PLANT
24/102
Mechanical equipment in Thermal
power station.
BOILER
ECONOMISER
TURBINE
SUPER HEATER
AIR PREHEATER
CONDENSER
-
8/12/2019 STEAM PLANT
25/102
Superheater
The superheater consists of a superheater headerand superheater elements. Steam from the main
steam pipe arrives at the saturated steam chamber
of the superheater header and is fed into thesuperheater elements. Superheated steam arrives
back at the superheated steam chamber of the
superheater header and is fed into the steam pipe to
the cylinders. Superheated steam is more
expansive.
-
8/12/2019 STEAM PLANT
26/102
Advantages of superheated steamCapacity to do work is increased without
increasing its pressure.
High temperature of super heated steam resultsin an increase in thermal efficiency.
Heat losses due to condensation of stem on
cylinder walls are avoided to a great extent.Does not produce corrosion effect on turbine.
-
8/12/2019 STEAM PLANT
27/102
Superheater It is a heating device.
It is used to raise temp of steam at const
pressure.
It removes even last traces of moisture.
-
8/12/2019 STEAM PLANT
28/102
Classification of super heaterConvection.
Radiation.
Combination of convection and radiation.
-
8/12/2019 STEAM PLANT
29/102
Reheater
The reheater functions similar to the superheater
in that it serves to elevate the steam temperature.
Primary steam is supplied to the high pressure
turbine. After passing through the high pressure
turbine, the steam is returned to the steam
generator for reheating (in a reheater) after which
it is sent to the low pressure turbine. A secondreheat cycle may also be provided.
-
8/12/2019 STEAM PLANT
30/102
Soot Blowers
The fuel used in thermal power plants causes sootand this is deposited on the boiler tubes,
economizer tubes, air pre heaters, etc. This
drastically reduces the amount of heat transfer of
the heat exchangers. Soot blowers control the
formation of soot and reduce its corrosive effects.
The types of soot blowers are fixed type, which
may be further classified into lane type and masstype depending upon the type of spray and nozzle
used.
-
8/12/2019 STEAM PLANT
31/102
CondenserThe use of a condenser in a power plant is to
improve the efficiency of the power plant by
decreasing the exhaust pressure of the steam
below atmosphere. Another advantage of the
condenser is that the steam condensed may be
recovered to provide a source of good pure feed
water to the boiler and reduce the water softeningcapacity to a considerable extent. A condenser is
one of the essential components of a power plant.
-
8/12/2019 STEAM PLANT
32/102
Functions of Condensers
The main purposes of the condenser are to
condense the exhaust steam from the turbine for
reuse in the cycle and to maximize turbine
efficiency by maintaining proper vacuum. As the
operating pressure of the condenser is lowered
(vacuum is increased), the enthalpy drop of the
expanding steam in the turbine will also increase.This will increase the amount of available work
from the turbine (electrical output).
-
8/12/2019 STEAM PLANT
33/102
Cooling TowerThe importance of the cooling tower is felt when
the cooling water from the condenser has to be
cooled. The cooling water after condensing thesteam becomes hot and it has to be cooled as it
belongs to a closed system. The Cooling towers
do the job of decreasing the temperature of the
cooling water after condensing the steam in the
condenser.
-
8/12/2019 STEAM PLANT
34/102
Cooling Towers have one function :
Remove heat from the water discharged from
the condenser so that the water can bedischarged to the river or re-circulated and
reused.
-
8/12/2019 STEAM PLANT
35/102
A cooling tower extracts heat from water by
evaporation. In an evaporative cooling tower, a
small portion of the water being cooled isallowed to evaporate into a moving air stream
to provide significant cooling to the rest of that
water stream.
-
8/12/2019 STEAM PLANT
36/102
Cooling Towers are commonly used to provide
lower than ambient water temperatures and aremore cost effective and energy efficient than
most other alternatives. The smallest cooling
towers are structured for only a few litres of
water per minute while the largest cooling
towers may handle upwards of thousands of
litres per minute. The pipes are obviously much
larger to accommodate this much water in thelarger towers and can range up to 12 inches in
diameter.
-
8/12/2019 STEAM PLANT
37/102
Advantages of regenerative cycle Improve overall plant efficiency.
Protect boiler corrosion.
Avoid the thermal stresses due to cold water
entering the boiler .
Increased the quantity of steam produced by
boiler.
-
8/12/2019 STEAM PLANT
38/102
Function of economizer To extract a part of heat from the fuel gas
coming out of the boiler.
To use heat for heating feed water to the boiler.
To increases the efficiency of boiler.
-
8/12/2019 STEAM PLANT
39/102
The economizer is a feed water heater, deriving
heat from the flue gases. The justifiable cost of
the economizer depends on the total gain inefficiency. In turn this depends on the flue gas
temperature leaving the boiler and the feed
water inlet temperature.
-
8/12/2019 STEAM PLANT
40/102
Air Pre-heater
The flue gases coming out of the economizer is
used to preheat the air before supplying it tothe combustion chamber. An increase in air
temperature of 20 degrees can be achieved by
this method. The pre heated air is used forcombustion and also to dry the crushed coal
before pulverizing.
-
8/12/2019 STEAM PLANT
41/102
Advantages of mechanical handlingHigher reliability.
Less labour required.
Operation is easy and smooth.
Economical for large capacity plant.
Losses in transport are minimised.
Easily started.
-
8/12/2019 STEAM PLANT
42/102
Disadvantages of mechanical handlingNeed continuous maintenance and repair.
Capital cost of plant is increased.
-
8/12/2019 STEAM PLANT
43/102
Working diagram Thermal
power station.
-
8/12/2019 STEAM PLANT
44/102
Side view Thermal power station.
Steam Turbine Power PlantTotal
-
8/12/2019 STEAM PLANT
45/102
C
saturatedwater
Gen
compressedwater
superheatedsteam
cooling water
PumpSteamTurbine
Condenser
Steam Generator
Steam Turbine Power Plant
saturatedsteam
hot gases
Heat
WorkoutTotal
Workin
inTotal
Loss???Where???
A di t th
-
8/12/2019 STEAM PLANT
46/102
R. Shanthini 15Aug 2010
According to the2ndLaw of Thermodynamics
when heat is converted into work,part of the heat energy must be wasted
Power generation
type
Unit size
(MW)
Energy wasted
(MW)
Diesel engine 10 - 30 7 22
Gas Turbine 50 - 100 36 78
Steam Turbine 200 - 800 120
560Combined (ST & GT) 300 - 600 150 380
Nuclear (BWR & PWR) 500 - 1100 330 760
9-1
-
8/12/2019 STEAM PLANT
47/102
The Simple Ideal Rankine Cycle
The McGraw-Hill Companies, Inc.,1998
-
8/12/2019 STEAM PLANT
48/102
How can We Increase the Efficiency of the
Rankine cycle?
Rankine cycle efficiency can be increased by
increasing average temperature at which heat is
transferred to the working fluid in the boiler ordecreasing the average temperature at which
heat is rejected from the working fluid in the
condenser. That is, the average fluid
temperature should be as high as possible
during heat addition and as low as possible
during heat rejection.
-
8/12/2019 STEAM PLANT
49/102
The three ways by which eff iciency of the
Rankine cycle can be increased are :
(a) Lowering the condenser pressure.(b) Superheating the steam to high temperatures.
(c) Increasing the boiler pressure.
-
8/12/2019 STEAM PLANT
50/102
The thermal efficiency of the Rankine cyclecan be increased by increasing the averagetemperature at which heat is added to the
working fluid and/or by decreasing the averagetemperature at which heat is rejected to thecooling medium. The average temperatureduring heat rejection can be decreased by
lowering the turbine exit pressure.
-
8/12/2019 STEAM PLANT
51/102
-
8/12/2019 STEAM PLANT
52/102
Superheating has the added advantage of decreasing
the moisture content of the steam at the turbine exit.
Lowering the exhaust pressure or raising the boiler
pressure, however, increases the moisture content.
To take advantage of the improved efficiencies at
higher boiler pressures and lower condenser
pressures, steam is usually reheatedafter expanding
partially in the high-pressure turbine.
-
8/12/2019 STEAM PLANT
53/102
This is done by extracting the steam after
partial extraction in the high-pressure turbine,
sending it back to the boiler where it isreheated at constant pressure, and returning it
to the low-pressure turbine for complete
expansion to the condenser pressure.
-
8/12/2019 STEAM PLANT
54/102
The average temperature during the reheatprocess, and thus the thermal efficiency of thecycle, can be increased by increasing thenumber of expansion and reheat stages. As the
number of stages is increased, the expansionand reheat processes approach an isothermalprocess at maximum temperature. Reheating
also decreases the moisture content at theturbine exit.
-
8/12/2019 STEAM PLANT
55/102
Another way of increasing the thermal efficiency of
the Rankine cycle is by regeneration. During aregeneration process, liquid water (feed water)
leaving the pump is heated by some steam bled off
the turbine at some intermediate pressure in devicescalled feed water heaters.
-
8/12/2019 STEAM PLANT
56/102
The two streams are mixed in open feed water
heaters, and the mixture leaves as a saturated
liquid at the heater pressure. In closed feedwater heaters, heat is transferred from the
steam to the feed water without mixing.
-
8/12/2019 STEAM PLANT
57/102
The production of more than one useful form ofenergy (such as process heat and electric power)
from the same energy source is called cogeneration.
Cogeneration plants produce electric power whilemeeting the process heat requirements of certain
industrial processes. This way, more of the energy
transferred to the fluid in the boiler is utilized for a
useful purpose. The faction of energy that is used for
either process heat or power generation is called the
utilization factor of the cogeneration plant.
-
8/12/2019 STEAM PLANT
58/102
The overall thermal efficiency of a power plantcan be increased by using binary cycles or
combined cycles. A binary cycle is composed of
two separate cycles, one at high temperatures
(topping cycle) and the other at relatively low
temperatures.
-
8/12/2019 STEAM PLANT
59/102
The most common combined cycle is the gas-steam combined cycle where a gas-turbinecycle operates at the high-temperature rangeand a steam-turbine cycle at the low-temperature range. Steam is heated by thehigh-temperature exhaust gases leaving the gas
turbine. Combined cycles have a higherthermal efficiency than the steam- or gas-turbine cycles operating alone.
-
8/12/2019 STEAM PLANT
60/102
-
8/12/2019 STEAM PLANT
61/102
Selection of plant site AVAI LABI L I TY OF COAL.
Huge quanti ty of coal is required for large thermal
plants.
ASH DI SPOSAL FACIL I TIES.
SPACE REQUIREMENT.
NATURE OF LAND.
AVAI LABI L I TY OF WATER.
-
8/12/2019 STEAM PLANT
62/102
Selection of plant site TRANSPORT FACIL I TYIES.
AVAI LABI L I TY OF LABOUR.
PUBL IC PROBLEMS.
SIZE OF THE PLANT.
-
8/12/2019 STEAM PLANT
63/102
Nowadays, the environment protection has
become a crucial problem and the authoritiesare requested to set increasingly more stringent
limits , one of which is the emissions from the
industrial plants of solid particulate and other
gaseous pollutants.
Background
ABOUT ELECTROSTATIC
PRECIPITATOR
-
8/12/2019 STEAM PLANT
64/102
ABOUT ELECTROSTATICPRECIPITATOR
Electrostatic precipitator (ESP) is a widely
used device in so many different domainsto remove the pollutant particulates,
especially in industrial plants.
What is ESP
-
8/12/2019 STEAM PLANT
65/102
HOW ESP WORKS
Generally, the processes of electrostatic
precipitator are known as three main stages:
particle charging, transport and collection.
Main process of ESP
-
8/12/2019 STEAM PLANT
66/102
To characterize all these stages determines to
take a great number of basic phenomena into
account from a physical point of view whenthey occurred.
Introduction
These are stages interacted that originated
from the complexity of the processes of
precipitator.
-
8/12/2019 STEAM PLANT
67/102
Schematic of wire-plate ESP
Schematic of wire-plate electrostatic
precipitator
-
8/12/2019 STEAM PLANT
68/102
Mechanism of ESP
Mechanism of electrostatic precipitator
-
8/12/2019 STEAM PLANT
69/102
PROCESS OF Particle charging
Particle charging is the first and foremost
beginning in processes.
As the voltage applied on precipitator
reach threshold value, the space inside
divided into ionization region and driftregion.
-
8/12/2019 STEAM PLANT
70/102
The electric field magnitude around thenegative electrode is so strong that the
electrons escape from molecule.
Under the influence of electric field, the positive
ions move towards the corona, while the negative
ions and electrons towards the collecting plates.
-
8/12/2019 STEAM PLANT
71/102
Particle transport
In the moving way, under the influence of electricfield, negative ions cohere and charge the particles,
make the particles be forced towards collecting-
plate.
-
8/12/2019 STEAM PLANT
72/102
Particle collectionAs soon as the particles reach the plate,
they will be neutralized and packed by the
succeeded ones subsequently. Thecontinuous process happens, as a result,
particles are collected on the collecting
plate.
-
8/12/2019 STEAM PLANT
73/102
73
What is a Boiler?
Introduction
Vessel that heats water to become hot water
or steam
At atmospheric pressure water volume
increases 1,600 times
Hot water or steam used to transfer heat to aprocess
-
8/12/2019 STEAM PLANT
74/102
-
8/12/2019 STEAM PLANT
75/102
A boiler should ful f i l l the fol lowing requi rements
(a) Safety : The boiler should be safe under
operating conditions.
(b) Accessibility : The various parts of the boiler
should be accessible for repair and maintenance.
(c) Capacity : The boiler should be capable of
supplying steam according to the requirements.
-
8/12/2019 STEAM PLANT
76/102
(d) Efficiency : To permit efficient operation, the boiler
should be able to absorb a maximum amount of heatproduced due to burning of fuel in the furnace.
(e) It should be simple in construction and its maintenance
cost should be low.
(f) Its initial cost should be low.
(g) The boiler should have no joints exposed to flames.
(h) The boiler should be capable of quick starting and
loading.
I t d ti
-
8/12/2019 STEAM PLANT
77/102
Introduction
BURNERWATER
SOURCE
BRINE
SOFTENERSCHEMICAL FEED
FUELBLOW DOWN
SEPARATOR
VENT
VENTEXHAUST GASSTEAM TO
PROCESS
STACK DEAERATOR
PUMPS
Figure: Schematic overview of a boiler room
BOILER
ECO-
NOMI-ZER
T f B il
-
8/12/2019 STEAM PLANT
78/102
Types of Boilers
1. Fire Tube Boiler
2. Water Tube Boiler
3. Packaged Boiler4. Fluidized Bed (FBC) Boiler
5. Stoker Fired Boiler
6. Pulverized Fuel Boiler7. Waste Heat Boiler
8. Thermic Fluid Heater (not a boiler!)
What Type of Boilers Are There?
-
8/12/2019 STEAM PLANT
79/102
The boilers can be classif ied according to the
following cr iter ia.According to flow of water and hot gases :
(a) Water tube
(b) Fire tube.
-
8/12/2019 STEAM PLANT
80/102
Type of Boilers
1. Fire Tube Boiler
Relatively small steam
capacities (12,000 kg/hour)
Low to medium steam
pressures (18 kg/cm2)
Operates with oil, gas or solid
fuels
Type of Boilers
-
8/12/2019 STEAM PLANT
81/102
Type of Boilers
2. Water Tube Boiler
Used for high steam demand
and pressure requirements
Capacity range of 4,500
120,000 kg/hour
Combustion efficiency
enhanced by induced draft
provisions Lower tolerance for water
quality and needs water
treatment plant
3. Packaged Boiler
-
8/12/2019 STEAM PLANT
82/102
Oil
Burner
To
Chimney
Comes in complete package Features
High heat transfer
Faster evaporation
Good convective heattransfer
Good combustion efficiency
High thermal efficiency
Classified based on number ofpasses
THERMAL POWER PLANT
-
8/12/2019 STEAM PLANT
83/102
THERMAL POWER PLANT
AUXILIARIES
FD fans.
ID fans.
Boiler feed Water pumps.
Condensate extraction pumps.
Circulation Cooling Water Pumping system.
Cooling Towers .
CT Fans. PA fans.
Coal Mills.
-
8/12/2019 STEAM PLANT
84/102
Working of power plant
Pulverized coalis air-blown into the furnace from fuelnozzles at the four corners and it rapidly burns, forming a
large fireball at the center. Thethermal radiationofthe fireball heats the water that circulates through the boiler
tubes near the boiler perimeter. The water circulation rate in
the boiler is three to four times the throughput and is
typically driven by pumps. As the water in the boilercirculates it absorbs heat and changes into steam at 700 F
(371 C) and 3,200 psi
http://en.wikipedia.org/wiki/Coal_dusthttp://en.wikipedia.org/wiki/Coal_dusthttp://en.wikipedia.org/wiki/Thermal_radiationhttp://en.wikipedia.org/wiki/Boilerhttp://en.wikipedia.org/wiki/Boilerhttp://en.wikipedia.org/wiki/Thermal_radiationhttp://en.wikipedia.org/wiki/Thermal_radiationhttp://en.wikipedia.org/wiki/Thermal_radiationhttp://en.wikipedia.org/wiki/Coal_dusthttp://en.wikipedia.org/wiki/Coal_dusthttp://en.wikipedia.org/wiki/Coal_dusthttp://en.wikipedia.org/wiki/Coal_dusthttp://en.wikipedia.org/wiki/Coal_dusthttp://en.wikipedia.org/wiki/Coal_dusthttp://en.wikipedia.org/wiki/Coal_dusthttp://en.wikipedia.org/wiki/Coal_dusthttp://en.wikipedia.org/wiki/Coal_dusthttp://en.wikipedia.org/wiki/Coal_dusthttp://en.wikipedia.org/wiki/Coal_dusthttp://en.wikipedia.org/wiki/Coal_dust -
8/12/2019 STEAM PLANT
85/102
The water enters the boiler through a section in the
convection pass called the economizer. Fromthe economizer it passes to the steam drum.Once the water enters the steam drum it goes down
to the lower inlet water wall headers. From the inletheaders the water rises through the water walls and
is eventually turned into steam due to the heat being
generated by the burners located on the front andrear water walls (typically). As the water is turned
into steam/vapor in the water walls, the steam/vapor
once again enters the steam drum.
http://en.wikipedia.org/wiki/Economizerhttp://en.wikipedia.org/wiki/Steam_drumhttp://en.wikipedia.org/wiki/Steam_drumhttp://en.wikipedia.org/wiki/Steam_drumhttp://en.wikipedia.org/wiki/Steam_drumhttp://en.wikipedia.org/wiki/Economizer -
8/12/2019 STEAM PLANT
86/102
The steam/vapor is passed through a series of steamand water separators and then dryers inside the
steam drum. The steam separatorsand dryers
remove water droplets from the steam and the cyclethrough the water walls is repeated. This process is
known as natural circulation.
http://en.wikipedia.org/wiki/Steam_separatorhttp://en.wikipedia.org/wiki/Natural_circulationhttp://en.wikipedia.org/wiki/Natural_circulationhttp://en.wikipedia.org/wiki/Steam_separator -
8/12/2019 STEAM PLANT
87/102
super heaterFossil fuel power plants can have a super
heater and/or re-heater section in the steam
generating furnace. In a fossil fuel plant, afterthe steam is conditioned by the drying
equipment inside the steam drum, it is piped
from the upper drum area into tubes inside anarea of the furnace known as the super
heater,
http://en.wikipedia.org/w/index.php?title=Super_heater&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Super_heater&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Super_heater&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Super_heater&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Super_heater&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Super_heater&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Super_heater&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Super_heater&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Super_heater&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Super_heater&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Super_heater&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Super_heater&action=edit&redlink=1 -
8/12/2019 STEAM PLANT
88/102
which has an elaborate set up of tubing where
the steam vapor picks up more energy from hot
flue gases outside the tubing and itstemperature is now superheated above the
saturation temperature. The superheated steam
is then piped through the main steam lines to
the valves before the high pressure turbine.
-
8/12/2019 STEAM PLANT
89/102
Condenser
The condenser condenses the steam from the
exhaust of the turbine into liquid to allow it to
be pumped. If the condenser can be madecooler, the pressure of the exhaust steam is
reduced and efficiency of the cycleincreases.
http://en.wikipedia.org/wiki/Rankine_cyclehttp://en.wikipedia.org/wiki/Rankine_cycle -
8/12/2019 STEAM PLANT
90/102
For best efficiency, the temperature in the
condenser must be kept as low as practical inorder to achieve the lowest possible pressure in
the condensing steam. Since the condenser
temperature can almost always be keptsignificantly below 100 C where the vapor
pressureof water is much less than atmospheric
pressure, the condenser generally works undervacuum.Thus leaks of non-condensible air intothe closed loop must be prevented.
http://en.wikipedia.org/wiki/Vapor_pressurehttp://en.wikipedia.org/wiki/Vapor_pressurehttp://en.wikipedia.org/wiki/Vacuumhttp://en.wikipedia.org/wiki/Vacuumhttp://en.wikipedia.org/wiki/Vapor_pressurehttp://en.wikipedia.org/wiki/Vapor_pressurehttp://en.wikipedia.org/wiki/Vapor_pressure -
8/12/2019 STEAM PLANT
91/102
The condenser generally uses either
circulating cooling water from a cooling
tower to reject waste heat to theatmosphere, or once-through water from a
river, lake or ocean.
http://en.wikipedia.org/wiki/Cooling_towerhttp://en.wikipedia.org/wiki/Cooling_towerhttp://en.wikipedia.org/wiki/Cooling_towerhttp://en.wikipedia.org/wiki/Cooling_towerhttp://en.wikipedia.org/wiki/Cooling_towerhttp://en.wikipedia.org/wiki/Brass -
8/12/2019 STEAM PLANT
92/102
The condenser tubes are made of brass or
stainless steel to resist corrosion from eitherside. Nevertheless they may become internally
fouled during operation by bacteria or algae in the
cooling water or by mineral scaling, all of whichinhibit heat transfer and reduce
thermodynamic efficiency. Many plants
include an automatic cleaning system that circulatessponge rubber balls through the tubes to scrub them
clean without the need to take the system off-line
http://en.wikipedia.org/wiki/Brasshttp://en.wikipedia.org/wiki/Stainless_steelhttp://en.wikipedia.org/wiki/Thermodynamic_efficiencyhttp://en.wikipedia.org/wiki/Thermodynamic_efficiencyhttp://en.wikipedia.org/wiki/Thermodynamic_efficiencyhttp://en.wikipedia.org/wiki/Thermodynamic_efficiencyhttp://en.wikipedia.org/wiki/Stainless_steelhttp://en.wikipedia.org/wiki/Stainless_steelhttp://en.wikipedia.org/wiki/Stainless_steelhttp://en.wikipedia.org/wiki/Brass -
8/12/2019 STEAM PLANT
93/102
Re heaterPower plant furnaces may have a re heater
section containing tubes heated by hot flue
gases outside the tubes. Exhaust steam from thehigh pressure turbine is rerouted to go inside
the re heater tubes to pickup more energy to go
drive intermediate or lower pressure turbines.
-
8/12/2019 STEAM PLANT
94/102
Non toxic dust Sulphurous anhydride
Carbon monoxide
Nitrogen dioxide Soot (fly ash)
Hydrogen sulphide
Pollution can be define as the contamination of soil ,
air and water with undesirable amount of mater ial
and heat.
Main pollutants from a power system
-
8/12/2019 STEAM PLANT
95/102
The major sources for air pollution are I-stackgases, discharge by thermal power plant, industrialenterprise and exhaust gases emitted byautomobiles.
The basic pollutants from nuclear power plantare;
Strontium 90, Strontium 89,
Bita and gama active aerosols
I odine isotopes
Radio-active inert gases
-
8/12/2019 STEAM PLANT
96/102
Acid rain; the rain which contain acid as its constituents,brings all the acid down from high above the environment.
Contaminant; it is the another name of pollution. It isundesirable substances which may be physical, chemical orbiological.
Pollutant; these are undesirable substances present in the
environment these can be NO2, SO2, CO2,smoke,salt, bacteria.
-
8/12/2019 STEAM PLANT
97/102
Radium
Thorium
Uranium
Plutonium.
The basic radio active pollutants
-
8/12/2019 STEAM PLANT
98/102
Wet scrubbers; used for removal of gases.
Electrostatic precipitator.
Bag house filters useful in removing thepalticulate matters where low sulphur coal is
used.
Fossil fuel fault system; to discharge solidwaste such as calcium and magnesium.
The solid waste disposal equipment
-
8/12/2019 STEAM PLANT
99/102
Lot of heat is injected into biosphere from
thermal power plant, through exhaust gases and
waste water. The major problem is the effect ofdischarge of large quantity of heated wasted
water into natural water basins. Hot water
raises the temperature and disturbs the natural
ecological balance
Bad effects of thermal pollution
-
8/12/2019 STEAM PLANT
100/102
-
8/12/2019 STEAM PLANT
101/102
Due to limited generating capacity diesel
power stations is not suitable for base load
plants.Nuclear power stations is not suitable for peak
load plants.
Incremental rate curve shows that asoutput power increases, cost of plant also
increases.
-
8/12/2019 STEAM PLANT
102/102
top related