Why Thermal Power Plants are always situated by the side of rivers or lakes?
Answer: Thermal Power Plants are situated close to the rivers or lakes because to meet the large quantity of the water requirement. Water is required in the steam power plants
- steam in the boiler
- for cooling purposes such as in condensers
- as carrying medium such as in disposal of ash
- for drinking purpose
What is the purpose of deaerator in steam power plant?
Answer: The presence of dissolved gases like oxygen and carbon dioxide in water makes the water corrosive, as they react with metal and forms iron oxide. The solubility of the gases in the water decreases with increase in the temperature and becomes zero at boiling point or saturation point.The purpose of the deaerator is to reduce the dissolved oxygen content in the condensate ( feed water) by increasing its temperature. These gases are removed in the deaerator by heating the feed water to saturation temperature through the bled steam from the turbine.
Why cooling towers require in the Steam power plant ?
Answer: Cooling towers cool the warm water discharged from the condenser and feed the cooled water back to the condenser. There are two types of cooling methods provided in the cooling towers, they can be either wet type or dry type
Wet type Cooling towers: In wet cooling towers warm water from the condenser are made to spray on slats or horizontal bars and air is passed from bottom, as the water splashes down from one slat to other due to gravity air and water mixes and heat is rejected in to the air
Dry type Cooling tower: Dry type towers are employed where the cooling water is not available in plenty. In dry type warm water from condensate is made to flow through the finned tubes over which cooling air is passed. Heat is rejected to air as water is cooled
Why are feed water heaters are used?
Answer:Regenerative Feedwater heaters are employed in steam power plants to improve the cycle efficiency. Also it increases the steam flow rate and reduces the steam flow to the condenser. They raise the temperature of the feed water before it enters the economizer