COOLING TOWER

What Is Thermal Power Plant?

A thermal power station is a plant where water is heated, until it turns into steam which drives the steam engine. When it runs through the system it is condensed and turned to water state again and is re-heated. It goes through the same system as are cycling process. On the other hand Dendro thermal power is the production of electricity from wood

COMPONENT PARTS OF THERMAL POWER PLANT

Typical diagram of a coal-fired thermal power station

1. Cooling tower10. Steam Control valve19. Superheater

2. Cooling water pump11. High pressure steam turbine20. Forced draught (draft) fan

3. Transmission line (3-phase)12. Deaerator21. Reheater

4. Step-up transformer (3-phase)13. Feedwater heater22. Combustion air intake

5. Electrical generator (3-phase)14. Coal conveyor23. Economiser

6. Low pressure steam turbine15. Coal hopper24. Air preheater

7. Condensate pump16. Coal pulverizer25. Precipitator

8. Surface condenser17. Boiler steam drum26. Induced draught (draft) fan

9. Intermediate pressure steam turbine18. Bottom ash hopper27. Flue-gas stack

WHAT IS BOILER :

Boiler is an energy conversion device, the energy input to the boiler with the fuel chemical energy, electrical energy, high-temperature flue gas heat, etc., and after boiler conversion, exporting has a certain heat of steam, hot water or organic heat carrier . The original meaning refers to the pot on the fire heated the water container, fuel burning furnace refers to the place, including the boiler and furnace boiler two parts. Boiler to generate hot water or steam directly for industrial production and people's lives to provide the necessary heat, steam power plant can also be converted to mechanical energy, or through the generator to convert mechanical energy into electrical energy. Boiler to provide hot water as hot water boilers, mainly for domestic, industrial production is also a small amount of applications. Steam boiler as steam boilers, often referred to as boiler, used for thermal power plants, ships, locomotives and industrial and mining enterprises. Fired Boiler Steam Boilers Acme Electric Boilers

Definition of Boiler

Steam boiler or simply a boiler is basically a closed vessel into which water is heated until the water is converted into steam at required pressure. This is most basic definition of boiler.

Working Principle of BoilerThe basic working principle of boiler is very very simple and easy to understand. The boiler is essentially a closed vessel inside which water is stored. Fuel (generally coal) is bunt in a furnace and hot gasses are produced. These hot gasses come in contact with water vessel where the heat of these hot gases transfer to the water and consequently steam is produced in the boiler. Then this steam is piped to the turbine of thermal power plant. There are many different types of boiler utilized for different purposes like running a production unit, sanitizing some area, sterilizing equipment, to warm up the surroundings etc. Advantages of Fire Tube Boiler

Steam Boiler Efficiency

The percentage of total heat exported by outlet steam in the total heat supplied by the fuel(coal) is called Steam boiler efficiency.

It includes with thermal efficiency, combustion efficiency & fuel to steam efficiency. Steam boiler efficiency depends upon the size of boiler used. A typical efficiency of steam boiler is 80% to 88%. Actually there are some losses occur like incomplete combustion, radiating loss occurs from steam boiler surrounding wall, defective combustion gas etc. Hence, efficiency of steam boiler gives this result.Advantages

1) It is quite compact in construction.2) Fluctuation of steam demand can be met easily.3) It is also quite cheap.

Disadvantages

1) As the water required for operation of the boiler is quite large, it requires long time for rising steam at desired pressure.

2) As the water and steam are in same vessel the very high pressure of steam is not possible.

3) The steam received from fire tube boiler is not very dry.

Electrostatic precipitator (ESP)

An electrostatic precipitator (ESP), or electrostatic air cleaner is a particulate collection device that removes particles from a flowing gas (such as air) using the force of an induced electrostatic charge. Electrostatic precipitators are highly efficient filtration devices that minimally impede the flow of gases through the device, and can easily remove fine particulate matter such as dust and smoke from the air stream.^ In contrast to wet scrubbers which apply energy directly to the flowing fluid medium, an ESP applies energy only to the particulate matter being collected and therefore is very efficient in its consumption of energy (in the form of electricity).AdvantagesDisadvantages

Handles very large gas volumes and heavy dust loads with low pressure drop. Very high collection efficiencies, even for very small particles. Can handle corrosive materials, wet materials, and high temperatures. Low operating costs, except at very high efficiencies. Durable - has long service life requiring little maintenance. Not very flexible to changes in operating conditions once installed/purchased. Cannot control gaseous emissions Very dependent on the electrical resistively of the particulate. High capital (equipment) costs Very large footprint - takes up a lot of space.

ESP Operation

Electrostatic precipitators use electrostatic charges to separate particles from a dirty gas stream. High voltage, direct current electrodes are used to establish a strong electric field. This field (known as a corona) delivers a (usually) negative charge to particles as they pass through the device. This charge forces the particles onto the walls of collection plates or tubes. These collection surfaces (or collection electrodes) are then rapped, vibrated, or washed with water to dislodge the particles, which fall into a hopper to be disposed.

Two Stage ESP

In summary, the major components of a precipitator include:

Collection electrodes Discharge electrodes High voltage power supply Precipitator controls Rapping or spray washing systems Purge air systems

COOLING TOWER

A cooling tower is a heat rejection device which rejects waste heat to the atmosphere through the cooling of a water stream to a lower temperature. Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or, in the case of closed circuit dry cooling towers, rely solely on air to cool the working fluid to near the dry-bulb air temperature.

Common applications include cooling the circulating water used in oil refineries, petrochemical and other chemical plants, thermal power stations and HVAC systems for cooling buildings. The classification is based on the type of air induction into the tower: the main types of cooling towers are natural draft and induced draft cooling towers.

Cooling towers vary in size from small roof-top units to very large hyperboloid structures (as in the adjacent image) that can be up to 200 metres (660 ft) tall and 100 metres (330 ft) in diameter, or rectangular structures that can be over 40 metres (130 ft) tall and 80 metres (260 ft) long. The hyperboloid cooling towers are often associated with nuclear power plants, although they are also used to some extent in some large chemical and other industrial plants. Although these large towers are very prominent, the vast majority of cooling towers are much smaller, including many units installed on or near buildings to discharge heat from air conditioning.CHIMNEYA chimney is a structure which provides ventilation for hot flue gases or smoke from a boiler, stove, furnace or fireplace to the outside atmosphere. Chimneys are typically vertical, or as near as possible to vertical, to ensure that the gases flow smoothly, drawing air into the combustion in what is known as the stack, or chimney, effect. The space inside a chimney is called a flue. Chimneys may be found in buildings, steam locomotives and ships. In the United States, the term smokestack (colloquially, stack) is also used when referring to locomotive chimneys or ship chimneys, and the term funnel can also be used.

The height of a chimney influences its ability to transfer flue gases to the external environment via stack effect. Additionally, the dispersion of pollutants at higher altitudes can reduce their impact on the immediate surroundings. In the case of chemically aggressive output, a sufficiently tall chimney can allow for partial or complete self-neutralization of airborne chemicals before they reach ground level. The dispersion of pollutants over a greater area can reduce their concentrations and facilitate compliance with regulatory limits.

TURBINE GENERATOR

Principle of Operation and design:

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. No steam turbine is truly isentropic, however, with typical isentropic efficiencies ranging from 2090% based on the application of the turbine. The interior of a turbine comprises several sets of blades or buckets. 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.