Condenser and Cooling System

Importance of Condenser in Thermal Power Plant

Thermal Power Plant is based on the Rankine cycle and in Ideal Rankine cycle, there are 4 processes and those are Heat Addition at Constant Pressure in Boiler, Isentropic Expansion in Turbine, Constant Pressure Heat Rejection in Condenser and Isentropic Compression in Pumps. So now we will discuss about the condenser, which plays a very vital role in the cycle. 

So what is the purpose of condenser? Condenser condenses the steam which comes from the turbine into water at a very low pressure. But here the question arises why we need to condense the steam into water.it will be better if we directly send the steam back to the boiler without converting.

The reason is that if we want to dump the exit steam from the turbine to the boiler then we have to use a very large capacity compressor, which may take very high auxiliary power or you can say more than the power turbine is generating and that is not economical. As the total auxiliary consumption has to be as low as 9% of the total power generated, then only you will be able to supply more power to the customers. Also In mechanical term, we call it as a PMM2 (Perpetual Motion Machine),which takes heat from one source and gives work without rejecting any heat to the sink, But we know that we may not able to convert the total amount of heat into work. So when we use the condenser then high specific volume steam converts into low specific volume water and it’s easy to pump less quantity of water in comparison of high quantity steam. 

Importance of cooling tower:

As the name implies Cooling water cools the excess heat from water incurred during industrial operations into atmosphere. During this the water and the air come in contact in order to lower the temperature of the water circulating in various systems. They either use evaporation or cooling of the fluid (water) to do so. Cooling towers are widely used in oil refineries, petrochemical plants, thermal power plants, nuclear plants, food processing plants, natural gas plants etc. The cooling towers are normally placed within the industries. The cooling tower nozzles spray the hot water into the “fill media” where there is maximum surface area and this leads to water-air contact. In this way the water is cooled.

In view of more water requirement in Power plant, cooling water plays an important role in reduction of water quantity by reuse of the cooling water circuit, This concept is very useful where water shortage exists.