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Paper presentation on thermal power plant pdf writer

  • 07.05.2019

Steam condensing system consists of the following: a Condenser b Cooling water c Cooling tower d Hot well e Condenser cooling water pump f Condensate air extraction pump g Air extraction pump h Boiler feed pump i Make up water pump. Thermal energy released by combustion of fuel is transferred to water, which vaporizes and gets converted into steam at the desired temperature and pressure. The steam produced is used for: a Producing mechanical work by expanding it in steam engine or steam turbine.

Boiler is a closed vessel in which water is converted into steam by the application of heat. Usually boilers are coal or oil fired. According to flow of water and hot gases: a Water tube b Fire tube.

In water tube boilers, water circulates through the tubes and hot products of combustion flow over these tubes. In fire tube boiler the hot products of combustion pass through the tubes, which are surrounded, by water. Fire tube boilers have low initial cost, and are more compacts. But they are more likely to explosion, water volume is large and due to poor circulation they cannot meet quickly the change in steam demand. For the same output the outer shell of fire tube boilers is much larger than the shell of water-tube boiler.

Water tube boilers require less weight of metal for a given size, are less liable to explosion, produce higher pressure, are accessible and can respond quickly to change in steam demand. Tubes and drums of water-tube boilers are smaller than that of fire-tube boilers and due to smaller size of drum higher pressure can be used easily.

Water-tube boilers require lesser floor space. The efficiency of water-tube boilers is more. Therefore steam can be generated easily. Fire tube boilers are classified as follows: External Furnace a Horizontal return tubular b Short fire box c Compact. Vertical Tubular a Straight vertical shell, vertical tube b Cochran vertical shell horizontal tube. Various advantages of fire tube boilers are as follows: a Low cost b Fluctuations of steam demand can be met easily c It is compact in size.

According to position of furnace: a Internally fired b Externally fired In internally fired boilers the grate combustion chamber are enclosed within the boiler shell whereas in case of extremely fired boilers and furnace and grate are separated from the boiler shell.

According to the position of principle axis: a Vertical b Horizontal c Inclined. According to application: a Stationary b Mobile, Marine, Locomotive. According to the circulating water: a Natural circulation b Forced circulation. According to steam pressure: a Low pressure b Medium pressure c Higher pressure.

The justifiable cost of the economizer depends on the total gain in efficiency. In turn this depends on the flue gas temperature leaving the boiler and the feed water inlet temperature. A typical return bend type economizer is shown in the Figure. Air Pre-heater The flue gases coming out of the economizer is used to preheat the air before supplying it to the combustion chamber. An increase in air temperature of 20 degrees can be achieved by this method.

The pre heated air is used for combustion and also to dry the crushed coal before pulverizing. Soot Blowers The fuel used in thermal power plants causes soot and 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 mass type depending upon the type of spray and nozzle used. The other type of soot blower is the retractable soot blower. The advantages are that they are placed far away from the high temperature zone, they concentrate the cleaning through a single large nozzle rather than many small nozzles and there is no concern of nozzle arrangement with respect to the boiler tubes. Condenser The 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 softening capacity to a considerable extent. A condenser is one of the essential components of a power plant. Cooling Tower The importance of the cooling tower is felt when the cooling water from the condenser has to be cooled.

The cooling water after condensing the steam 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. This tower provides a horizontal air flow as the water falls down the tower in the form of small droplets.

The fan centered at the top of units draws air through two cells that are paired to a suction chamber partitioned beneath the fan. The outstanding feature of this tower is lower air static pressure loss as there is less resistance to air flow. The evaporation and effective cooling of air is greater when the air outside is warmer and dryer than when it is cold and already saturated. Superheater The superheater consists of a superheater header and superheater elements.

Steam from the main steam pipe arrives at the saturated steam chamber of the superheater header and is fed into the superheater 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. 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 boiler for reheating in a reheater after which it is sent to the low pressure turbine. A second reheat cycle may also be provided. It effects improvement and economy in the following ways: a The super heater increases the capacity of the plant.

The super heater steam temperature is controlled by spraying water. Other control methods that are according to the need and design are: a Excess Air Control b Flue Gas Recirculation c Gas by-pass Control d Control of Combination Superheaters e Adjustable Burner Control Excess Air Control The steam outlet temperature of a convection superheater may be increased at partial load by increasing the excess air supply.

The reduced gas temperature decreases the furnace heat absorption for the same steam production. The increased gas mass flow with its increased total heat content serves to increase the degree of superheat. Flue Gas Recirculation The recirculation of some percentage of the combustion gases serves to control steam temperature in the same manner as does an increase in excess air. By introducing the hot gases below the combustion zone, relatively high efficiency may be maintained.

Gas By-pass Control The boiler convection banks can be arranged in such a manner that portion of the gases can be by-passed around the superheater elements. The superheater is oversized so that it will produce the required degree of superheat at partial load conditions. As the load increases, some of the flue gases are by-passed. Control of Combination Superheaters The control of combination radiant-convection superheaters is relatively simple because of their compensating characteristics.

An increase in excess air reduces the radiant heat transfer but increases the convection heat transfer. The reduction in excess air has the opposite effect. Thus the combination superheaters can be operated over the entire control range without additional equipment.

Adjustable Burner Control With a multiple burner furnace it is possible to distribute the burners over a considerable burner wall height. This control is obtained by selective firing. Tiltable furnace may be adjusted to shift the position of the combustion zone. High pressure feed water heaters are used in the feed water system between the boiler feed pump discharge and the boiler, and utilize high pressure turbine extraction steam for heating the feed water.

Depending on turbine size, some turbines offer alternate number of extraction nozzles with usually a choice of using the highest pressure extraction nozzle. The selection, in this case, of the total number of feed water heaters to use should be based on economic evaluation. Low Pressure Heater s Use one or more low pressure feed water heaters to raise the temperature of condensate from condensate pump discharge temperature to the de-aerator inlet temperature. The heater drains are cascaded from the higher pressure heater to the next lower pressure heater with the lowest pressure heater draining to the condenser.

High Pressure Heater s Use one or more high pressure feed water heaters to raise the temperature of feed water from de-aerator outlet temperature to the required boiler economizer inlet temperature.

The heater drains are cascaded from heater to heater, back to the de-aerator in a fashion similar to the heater drain system for the low pressure heaters. Advantages a Fuel economy. A feedwater heater is a power plant component used to pre-heat water delivered to a steam generating boiler.

Preheating the feedwater reduces the irreversibilities involved in steam generation and therefore improves the thermodynamic efficiency of the system. This reduces plant operating costs and also helps to avoid thermal shock to the boiler metal when the feedwater is introduced back into the steam cycle.

In a steam power plant usually modeled as a modified Rankine cycle , feedwater heaters allow the feedwater to be brought up to the saturation temperature very gradually. This minimizes the inevitable irreversibilities associated with heat transfer to the working fluid water. It has almost completely replaced the reciprocating piston steam engine primarily because of its greater thermal efficiency and higher power-to-weight ratio. The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency through the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible process.

There are several classifications for modern steam turbines. Non-condensing or backpressure turbines are most widely used for process steam applications. The exhaust pressure is controlled by a regulating valve to suit the needs of the process steam pressure. These are commonly found at refineries, district heating units, pulp and paper plants, and desalination facilities where large amounts of low pressure process steam are available.

Reheat turbines are also used almost exclusively in electrical power plants. In a reheat turbine, steam flow exits from a high pressure section of the turbine and is returned to the boiler where additional superheat is added. The steam then goes back into an intermediate pressure section of the turbine and continues its expansion. Extracting type turbines are common in all applications.

In an extracting type turbine, steam is released from various stages of the turbine, and used for industrial process needs or sent to boiler feedwater heaters to improve overall cycle efficiency. Extraction flows may be controlled with a valve, or left uncontrolled. Induction turbines introduce low pressure steam at an intermediate stage to produce additional power. Single casing units are the most basic style where a single casing and shaft are coupled to a generator.

Tandem compound are used where two or more casings are directly coupled together to drive a single generator. A cross compound turbine arrangement features two or more shafts not in line driving two or more generators that often operate at different speeds. A cross compound turbine is typically used for many large applications. The interior of a turbine comprises se eral sets of lades, or u kets as the are ore o o l referred to. One set of stationary blades is connected to the casing and one set of rotating blades is connected to the shaft.

The sets intermesh with certain minimum clearances, with the size and configuration of sets varying to efficiently exploit the expansion of steam at each stage.

These stages are characterized by how the energy is extracted from them and are known as either impulse or reaction turbines. Most steam turbines use a mixture of the reaction and impulse designs each stage behaves as either one or the other, but the overall turbine uses both. Typically, higher pressure sections are impulse type and lower pressure stages are reaction type. These jets contain significant kinetic energy, which the rotor blades, shaped like buckets, convert into shaft rotation as the steam jet changes direction.

A pressure drop occurs across only the stationary blades, with a net increase in steam velocity across the stage. As the steam flows through the nozzle its pressure falls from inlet pressure to the exit pressure atmospheric pressure, or more usually, the condenser vacuum.

Due to this higher ratio of expansion of steam in the nozzle the steam leaves the nozzle with a very high velocity. The steam leaving the moving blades is a large portion of the maximum velocity of the steam when leaving the nozzle. The loss of e erg due to this higher e it elo it is o o l alled the arr o er elo it or lea i g loss.

This type of turbine makes use of the reaction force produced as the steam accelerates through the nozzles formed by the rotor. Steam is directed onto the rotor by the fixed vanes of the stator.

It leaves the stator as a jet that fills the entire circumference of the rotor. The steam then changes direction and increases its speed relative to the speed of the blades. A pressure drop occurs across both the stator and the rotor, with steam accelerating through the stator and decelerating through the rotor, with no net change in steam velocity across the stage but with a decrease in both pressure and temperature, reflecting the work performed in the driving of the rotor.

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. By lowering the condenser operating pressure, the following will occur: a Increased turbine output b Increased plant efficiency c Reduced steam flow for a given plant output It is therefore very advantageous to operate the condenser at the lowest possible pressure highest vacuum.

The older type Barometric and Jet-Type condensers operate on similar principles. Steam surface condensers are the most commonly used condensers in modern power plants. The source of the circulating water can be either a closed-loop i. The condensed steam from the turbine, called condensate, is collected in the bottom of the condenser, which is called a hotwell.

The condensate is then pumped back to the boiler to repeat the cycle. The exhaust steam from the low pressure turbine enters the shell where it is cooled and converted to condensate water by flowing over the tubes as shown in the diagram.

Such condensers use steam ejectors or rotary motor-driven exhausters for continuous removal of air and gases from the steam side to maintain vacuum. Figure: Diagram of a Typical Water-cooled Surface Condenser For best efficiency, the temperature in the condenser must be kept as low as practical in order to achieve the lowest possible pressure in the condensing steam. Since the condenser temperature can almost always be kept significantly below oC where the vapor pressure of water is much less than atmospheric pressure, the condenser generally works under vacuum.

Thus leaks of non- condensable air into the closed loop must be prevented. The condenser generally uses either circulating cooling water from a cooling tower to reject waste heat to the atmosphere, or once-through water from a river, lake or ocean. Figure: Typical Power Plant Condenser The diagram depicts a typical water-cooled surface condenser as used in power stations to condense the exhaust steam from a steam turbine driving an electrical generator as well in other applications.

In an evaporative cooling tower, a small portion of the water being cooled is allowed to evaporate into a moving air stream to provide significant cooling to the rest of that water stream. Cooling Towers are commonly used to provide lower than ambient water temperatures and are more 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 the larger towers and can range up to 12 inches in diameter. The water will emit heat as it is downward flowing which mixes with the above air flow, which in turn cools the water. Part of this water will also evaporate, causing it to lose even more heat. Open cooling towers, also called direct cooling towers, allow the water to come into contact with outside air.

If cooled water is returned from the cooling tower to be used again, some water must be added to replace the water that has been lost. Pollutants are able to enter into the water used in these processes and must be filtered out. Another method of combating the excess minerals and pollutants is some means of a dissolved solid control, such as a blow down. With this, a small percentage of the flow is drained off to aid in the removal of these contaminants.

This is fairly effective, but not as efficient as filtration. Closed loop or closed circuit cooling tower systems, also called indirect cooling tower systems, do not allow the water to come into contact with any outside substance, therefore keeping the water more pure due to the lack of foreign particles introduced.

Another classification of cooling towers is made between field assembled towers and factory assembled towers. Field assembled towers are shipped in pieces and assembled on site by a highly qualified and certified installation team. Factory assembled towers typically only require the fan motor to be mounted. Natural Draft Towers Natural draft towers are typically about m high, depending on the differential pressure between the cold outside air and the hot humid air on the inside of the tower as the driving force.

No fans are used. Whether the natural or mechanical draft towers are used depends on climatic and operating requirement conditions. The green flow paths show how the warm water leaves the plant proper, is pumped to the natural draft cooling tower and is distributed. The cooled water, including makeup from the lake to account for evaporation losses to the atmosphere, is returned to the condenser. Mechanical Draft Mechanical draft towers uses fans one or more to move large quantities of air through the tower.

They are two different classes: a Forced draft cooling towers b Induced draft cooling towers The air flow in either class may be cross flow or counter flow with respect to the falling water. Oil lubrication is provided to further reduce the friction between shaft and bearing surface and to limit the heat generated.

Barring gear Barring gear or turning gear is the mechanism provided to rotate the turbine generator shaft at a very low speed after unit stoppages. Once the unit is tripped i. When it stops completely, there is a tendency for the turbine shaft to deflect or bend if allowed to remain in one position too long. This is because the heat inside the turbine casing tends to concentrate in the top half of the casing, making the top half portion of the shaft hotter than the bottom half.

The shaft therefore could warp or bend by millionths of inches. This small shaft deflection, only detectable by eccentricity meters, would be enough to cause damaging vibrations to the entire steam turbine generator unit when it is restarted.

The shaft is therefore automatically turned at low speed about one percent rated speed by the barring gear until it has cooled sufficiently to permit a complete stop. The exhaust steam from the low pressure turbine enters the shell where it is cooled and converted to condensate water by flowing over the tubes as shown in the adjacent diagram. Such condensers use steam ejectors or rotary motor-driven exhausters for continuous removal of air and gases from the steam side to maintain vacuum.

For best efficiency, the temperature in the condenser must be kept as low as practical in order to achieve the lowest possible pressure in the condensing steam. Since the condenser temperature can almost always be kept significantly below C where the vapor pressure of water is much less than atmospheric pressure, the condenser generally works under vacuum.

Thus leaks of noncondensible air into the closed loop must be prevented. Plants operating in hot climates may have to reduce output if their source of condenser cooling water becomes warmer; unfortunately this usually coincides with periods of high electrical demand for air conditioning.

The condenser generally uses either circulating cooling water from a cooling tower to reject waste heat to the atmosphere, or once-through water from a river, lake or ocean. Feedwater heater In the case of a conventional steam-electric power plant utilizing a drum boiler, the surface condenser removes the latent heat of vaporization from the steam as it changes states from vapour to liquid.

The heat content joules or Btu in the steam is referred to as enthalpy. The condensate pump then pumps the condensate water through a Air ejector condenser and Gland steam exhauster condenser. From there the condensate goes to the deareator where the condenstae system ends and the Feedwater system begins. This reduces plant operating costs and also helps to avoid thermal shock to the boiler metal when the feedwater is introduced back into the steam cycle.

Deaerator A steam generating boiler requires that the boiler feed water should be devoid of air and other dissolved gases, particularly corrosive ones, in order to avoid corrosion of the metal. Generally, power stations use a deaerator to provide for the removal of air and other dissolved gases from the boiler feedwater. A deaerator typically includes a vertical, domed deaeration section mounted on top of a horizontal cylindrical vessel which serves as the deaerated boiler feedwater storage tank Cooling tower A cooling tower is a heat rejection device, which extracts waste heat to the atmosphere though the cooling of a water stream to a lower temperature.

The type of heat rejection in a cooling tower is termed evaporative in that it allows a small portion of the water being cooled to evaporate into a moving air stream to provide significant cooling to the rest of that water stream. Evaporative heat rejection devices such as cooling towers are commonly used to provide significantly lower water temperatures than achievable with air cooled or dry heat rejection devices, like the radiator in a car, thereby achieving more cost-effective and energy efficient operation of systems in need of cooling.

Natural Draft Cooling Tower 2. Mechanized Draft Cooling Tower i. Forced Draft cooling tower Induced Draft cooling tower Balanced Draft cooling tower Auxiliary systems Oil system An auxiliary oil system pump is used to supply oil at the start-up of the steam turbine generator. It supplies the hydraulic oil system required for steam turbines main inlet steam stop valve, the governing control valves, the bearing and seal oil systems, the relevant hydraulic relays and other mechanisms. At a preset speed of the turbine during start-ups, a pump driven by the turbine main shaft takes over the functions of the auxiliary system.

While small units may be cooled by air drawn through filters at the inlet, larger units generally require special cooling arrangements. Hydrogen gas cooling, in an oil-sealed casing, is used because it has the highest known heat transfer coefficient of any gas and for its low viscosity which reduces windage losses. This system requires special handling during start-up, with air in the chamber first displaced by carbon dioxide before filling with hydrogen.

This ensures that the highly flammable hydrogen does not mix with oxygen in the air. The hydrogen pressure inside the casing is maintained slightly higher than atmospheric pressure to avoid outside air ingress. The hydrogen must be sealed against outward leakage where the shaft emerges from the casing. Mechanical seals around the shaft are installed with a very small annular gap to avoid rubbing between the shaft and the seals.

Seal oil is used to prevent the hydrogen gas leakage to atmosphere. The generator also uses water cooling. Since the generator coils are at a potential of about 22 kV and water is conductive, an insulating barrier such as Teflon is used to interconnect the water line and the generator high voltage windings.

Demineralized water of low conductivity is used. Generator high voltage system The generator voltage ranges from 11 kV in smaller units to 22 kV in larger units. The generator high voltage leads are normally large aluminum channels because of their high current as compared to the cables used in smaller machines. They are enclosed in well-grounded aluminum bus ducts and are supported on suitable insulators.

The generator high voltage channels are connected to step-up transformers for connecting to a high voltage electrical substation of the order of kV to kV for further transmission by the local power grid. The necessary protection and metering devices are included for the high voltage leads. Thus, the steam turbine generator and the transformer form one unit. In smaller units, generating at 11 kV, a breaker is provided to connect it to a common 11 kV bus system.

Other systems Monitoring and alarm system Most of the power plant operational controls are automatic. However, at times, manual intervention may be required. Thus, the plant is provided with monitors and alarm systems that alert the plant operators when certain operating parameters are seriously deviating from their normal range. This is essential for a safe, damage-free shutdown of the units in an emergency situation. Its modern manifestation was invented by Sir Charles r Parsons in It has almost completely replaced the reciprocating piston steam engine primarily because of its greater thermal efficiency and higher power-to-weight ratio.

Because the turbine generates rotary. There are several classifications for modern steam turbines. Non condensing or back pressure turbines are most widely used for process steam applications. The exhaust pressure is controlled by a regulating valve to suit the needs of the process steam pressure. These are commonly found at refineries, district heating units, pulp and paper plants, and desalination facilities where large amounts of low pressure process steam are available.

Condensing turbines are most commonly found in electrical power plants. Reheat turbines are also used almost exclusively in electrical power plants. In a reheat turbine, steam flow exits from a high pressure section of the turbine and is returned to the boiler where additional superheat is added.

The steam then goes back into an intermediate pressure section of the turbine and continues its expansion. Extracting type turbines are common in all applications. In an extracting type turbine, steam is released from various stages of the turbine, and used for industrial process needs or sent to boiler feed water heaters to improve overall cycle efficiency.

Extraction flows may be controlled with a valve, or left uncontrolled. Induction turbines introduce low pressure steam at an intermediate stage to produce additional power.

Single casing units are the most basic style where a single casing and shaft are coupled to a generator. Tandem compound are used where two or more casings are directly coupled together to drive a single generator. A cross compound turbine arrangement features two or more shafts not in line driving two or more generators that often operate at different speeds.

A cross compound turbine is typically used for many large applications. Principal of design and operation An ideal steam turbine is considered to be an isentropic process, or constant entropy process, in which the entropy of the steam entering the turbine is equal to the entropy of the steam leaving the turbine. The interior of a turbine comprises several sets of blades, or buckets as they are more commonly referred to.

One set of stationary blades is connected to the casing and one set of rotating blades is connected to the shaft. The sets intermesh with certain minimum clearances, with the size and configuration of sets varying to efficiently exploit the expansion of steam at each stage.

These stages are characterized by how the energy is extracted from them and are known as either impulse or reaction turbines. Most steam turbines use a mixture of the reaction and impulse steam designs: each stage behaves as either one or the other, but the overall turbine uses both. Typically, higher pressure sections are impulse type and lower pressure stages are reaction type. These jets contain significant kinetic energy, which the rotor blades, shaped like buckets, convert into shaft rotation as the steam jet changes direction.

A pressure drop occurs across only the stationary blades, with a net increase in steam velocity across the stage. As the steam flows through the nozzle its pressure falls from inlet pressure to the exit pressure atmospheric pressure, or more usually, the condenser vacuum. Due to this higher ratio of expansion of steam in the nozzle the steam leaves the nozzle with a very high velocity.

The steam leaving the moving blades has a large portion of the maximum velocity of the steam when leaving the nozzle. The loss of energy due to this higher exit velocity is commonly called the "carry over velocity" or "leaving loss".

This type of turbine makes use of the reaction force produced as the steam accelerates through the nozzles formed by the rotor. Steam is directed onto the rotor by the fixed vanes of the stator. It leaves the stator as a jet that fills the entire circumference of the rotor. The steam then changes direction and increases its speed relative to the speed of the blades. A pressure drop occurs across both the stator and the rotor, with steam accelerating through the stator and decelerating through the rotor, with no net change in steam velocity across the stage but with a decrease in both pressure and temperature, reflecting the work performed in the driving of the rotor.

Also, a turning gear is engaged when there is no steam to the turbine to slowly rotate the turbine to ensure even heating to prevent uneven expansion.

Saddam Hussain Sohag 2. Jahiduzzaman Rubel 3. Mohsin Uddin 4.
A cross compound turbine arrangement features two or more shafts not in line driving two or more generators that often operate at different speeds. A feed water pump returns the condensed liquid condensate to the boiler. The boiler is a water tube boiler hanging from the top.

The dry steam then flows into the superheater coils. Evaporative heat rejection devices such as cooling towers are commonly used to provide significantly lower water temperatures than achievable with air cooled or dry heat rejection devices, like the radiator in a car, thereby achieving more cost-effective and energy efficient operation of systems in need of cooling. Steam power plants operate on sophisticated variants of the Rankine cycle. The piping and valves are generally of stainless steel. Single casing units are the most basic style where a single casing and shaft are coupled to a generator.
Since the generator coils are at a potential of about 22 kV and water is conductive, an insulating barrier such as Teflon is used to interconnect the water line and the generator high voltage windings. Early developments were very slow and Newcomen's design was used in England for nearly years. The boiler is a water tube boiler hanging from the top. The flow sheet of a thermal power plant consists of the following four main circuits: a Feed water and steam flow circuit.

The exhaust pressure is controlled by a regulating valve to suit the needs of the process steam pressure. Evaporative heat rejection devices such as cooling towers are commonly used to provide significantly lower water temperatures than achievable with air cooled or dry heat rejection devices, like the radiator in a car, thereby achieving more cost-effective and energy efficient operation of systems in need of cooling. In turn this depends on the flue gas temperature leaving the boiler and the feed water inlet temperature. In Bangladesh, the consumption of per capita generation is very low only kWh.
Paper presentation on thermal power plant pdf writer
Some prefer to use the term energy center because such facilities convert forms of heat energy into electrical energy. The greatest variation in the design of steam power stations is due to the different fuel sources. This will increase the amount of available work from the turbine electrical output. Double and triple expansion steam engines were common and there was scarcely a demand for mechanical energy which steam could not meet.

Its modern manifestation was invented by Sir Charles r Parsons in The heat transfer to the incoming water feed water first increases its temperature until it becomes a saturated liquid, then evaporates it to form saturated vapor, and usually then further raises its temperature to create superheated steam. The loss of e erg due to this higher e it elo it is o o l alled the arr o er elo it or lea i g loss. Steam condensing system consists of the following: a Condenser b Cooling water c Cooling tower d Hot well e Condenser cooling water pump f Condensate air extraction pump g Air extraction pump h Boiler feed pump i Make up water pump.
Paper presentation on thermal power plant pdf writer
The input at boiler is the DM water and pulverized coal with air. The DM water is prepared in the water treatment plant facility where it is deionized and deareated. It prepared in the scale of neutral liquid i. The coal is taken out from wagons with the help of a machine known as wagon tippler.
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Superheated steam arrives back at the superheated steam chamber of the superheater header and is fed into the steam pipe to the cylinders. Vertical Tubular a Straight vertical shell, vertical tube b Cochran vertical shell horizontal tube. Depending on turbine size, some turbines offer alternate number of extraction nozzles with usually a choice of using the highest pressure extraction nozzle. The other type of soot blower is the retractable soot blower.

Nisho

In this model, the fan is located at the base. This small shaft deflection, only detectable by eccentricity meters, would be enough to cause damaging vibrations to the entire steam turbine generator unit when it is restarted. Air path External fans are provided to give sufficient air for combustion. The simple Rankine cycle from which the cycles of large steam power plants are derived. Located near the centre are the cabinets which house the processors that execute the control functions.

Faern

In water tube boilers, water circulates through the tubes and hot products of combustion flow over these tubes.

Dakus

It began with Thomas Newcomen Dartmouth in the early 's. However, some storage is essential as the DM plant may be down for maintenance. Condenser The 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. Soot blowers control the formation of soot and reduce its corrosive effects. It consists of two MW units with an installed capacity of MW. The engine however, was extremely inefficient, and where coal had to be brought from a distance it was expensive to run.

Jular

Thus, installing coal-based thermal power plants based on advanced steam parameters in Bangladesh will be a prospective option aiding energy self-sufficiency. There are no louvered exterior walls. The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency through the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible process. In a well-designed heat exchanger, both fluids pass through with little pressure loss.

Douktilar

All mechanical towers must be located so that the discharge air diffuses freely without recirculation through the tower, and so that air intakes are not restricted. In a steam power plant usually modeled as a modified Rankine cycle , feedwater heaters allow the feedwater to be brought up to the saturation temperature very gradually. Mechanical Draft Mechanical draft towers uses fans one or more to move large quantities of air through the tower.

Ketilar

Watt re-designed the engine so that condensation occurred outside of the cylinder. In fire tube boiler the hot products of combustion pass through the tubes, which are surrounded, by water. In a well-designed heat exchanger, both fluids pass through with little pressure loss.

Doulrajas

Air taken from the atmosphere is first passed through the air pre-heater, where it is heated by flue gases. At this point the steam could be released into the atmosphere. However, at times, manual intervention may be required. The outlet of the LPT is sent to the condenser for condensing back to water by a cooling water system. Its modern manifestation was invented by Sir Charles r Parsons in

Meran

Theory: Steam cycles used in electrical power plants and in the production of shaft power in industry are based on the familiar Rankine cycle, studied briefly in most courses in thermodynamics. However, thermal power generation, which uses fossil fuels, causes more CO2 emissions than other power generation methods. An Independent Power Project IPP of the ministry is under implementation for improvement in generation and distribution of electricity by government and private agencies. In an evaporative cooling tower, a small portion of the water being cooled is allowed to evaporate into a moving air stream to provide significant cooling to the rest of that water stream.

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