How do thermal power plants work

Thermal power plants help me almost half of the world's power demand they use water as the working fluid today's thermal power plants are capable to run under green efficiency by conforming to stringent environmental standards in this video we will see how a coal-based thermal power plant achieves this in a detailed step-by-step manner by turning the shaft of this generator we will be able to generate electricity the generator derives motion from a steam turbine the heart of the power plant in order to turn steam turbine, you have to supply a high pressure and high temperature steam at the inlet of the turbine as the turbine absorbs energy from the high-energy fluid its pressure and temperature drop toward the outlet you can take a closer look at the uniquely shaped steam turbine rotor blades high capacity power plant often use different stages of steam turbines such as high pressure turbine intermediate pressure turbine and low pressure turbine. 

          So now we have met our objective, we have produced electricity from the generator if we can bring the low pressure and low temperature steam back to their original states which were of a much higher pressure and temperature we can repeat the process the first step is to raise the pressure you can use a compressor for this purpose but compressing steam is a highly energy intensive process and such a power plant will not be efficient at all the easy way is to convert the steam into liquid and boost the pressure for this purpose we'll introduce condenser heat exchangers which sit beneath the low pressure turbine in the condenser a stream of cold water flows through the tubes the steam rejects heat to this liquid stream and became condensed now we can use the pump to increase the pressure of this feed water typically multistage traffic pumping is used for this purpose. 

          That way the pressure will revert to its original state the next task is to bring the temperature back to its original value for this purpose heat is added to the exit of the pump with the help of a boiler high capacity power plants generally use a type of boiler called a "water tube boiler" pulverized coal is then burnt inside boiler the incoming water initially passes through any economizer session here the water will capture energy from the flue gas the water flow straight down-comer and then through water walls, where transforms into steam the pure steam is separated at a steam drum now the working fluid is back to its original state high pressure and high temperature this steam can be fed back into the steam turbine and the cycle can be repeated over and over again for continuous power production but a power plant working on this basic Rankine cycle will have a very low efficiency and a low capacity we can increase the performance of the power plant considerably with the help of a few simple techniques. 

          In case of super heating even after the liquid has been converted into steam even more heat is added and with that the steam becomes super-heated the higher the temperature of the steam the more efficient the cycle just remember the Carnot's theorem of maximum thermal efficiency possible but the steam turbine material will not withstand temperatures of more than 600 degrees Celsius so super heating is limited to the threshold the temperature of the steam decreases as it flows along the rows of the blade consequently a great way to increase the efficiency of the power plant is to add more heat after the first turbine stage this is known as reheating and it will increase the temperature of the steam again leading to a high power output and greater efficiency the low pressure size of the power plan are prone to suck the atmospheric air even with sophisticated ceiling arrangements. 

          The dissolved gases in the feed water will spoil the boiler material over time to remove these dissolved gases and open feedwater heater is introduced hot steam from the turbine is mixed into the feed water steam bubbles so generated will absorb the dissolved gases the mixing also preheats the feed water which helps improve the efficiency of the power plant to an even greater extent all these techniques make the modern power plant work under an efficiency range of forty to forty-five percent now we'll take a look at how heat addition and heat rejection are executed in an actual power plant the cold liquid is supplied at the condenser with the help of a cooling tower the heated up water from the condenser are rid is sprayed in the cooling tower which induces a natural air draft and the sprayed water loses heat this is how a colder liquid is always provided at the condenser inlet at a hydration inside the burning coal produces many pollutants we cannot release these pollutants directly into the atmosphere so before transferring them to a stack the exhaust gases cleaned in an Electro Static Precipitator the ESP uses plates with high voltage static electricity to absorb the pollutant particles we hope that we've given you new insights into the inner workings of thermal power plants Thank you.