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  1. 1. - VanitaThakkar Associate Professor, Mechanical Engineering Department, Babaria Institute ofTechnology,Varnama,Vadodara INTRODUCTION TO THERMAL POWER PLANTS
  2. 2. INTRODUCTION  A Power Plant / Power Station is an industrial facility for generation of Electric Power.  It is a set-up consisting of systems and sub-systems, equipments and auxiliaries required for the generation of Electricity, which involves conversion of energy forms like chemical energy, heat energy or gravitational potential energy into Electrical Energy. 2 VANITA N THAKKAR BIT, VARNAMA
  3. 3. ENERGY CONVERSION PROCESS IN POWER PLANT The energy content in a primary source of energy, like  Chemical Energy of a Fossil Fuel,  Potential Energy of water stored at a height,  Renewable / Non-conventional sources, like Solar Thermal Energy, Wind energy, Geothermal Energy, Tidal Energy,Wave Energy, etc. is converted stage-wise to Mechanical Energy (Rotational Energy) to obtain Electricity by creating relative motion between a magnetic field and a conductor. 3 VANITA N THAKKAR BIT, VARNAMA
  4. 4. THERMAL POWER PLANTS  In Thermal Power Plants, mechanical power is produced by a Heat Engine that transforms Thermal Energy, often from Combustion of a Fuel, into Rotational Energy.  Most Thermal Power Stations produce steam, and these are sometimes called Steam Power Plants / Stations.  Not all thermal energy can be transformed into mechanical power, according to the Second Law of Thermodynamics. Therefore, there is always heat lost to the environment.  If this loss is employed as useful heat, for industrial processes or distinct heating, the power plant is referred to as a Cogeneration Power plant or CHP (combined heat-and-power) plant. 4 VANITA N THAKKAR BIT, VARNAMA
  5. 5. RANKINE CYCLE  A Thermal Power Plant is a power plant in which the prime mover is steam driven.  Water is heated, turns into steam in Boiler and spins a Steam Turbine which either drives an Electrical Generator or does some other work, like Ship Propulsion.  After it passes through the turbine, the steam is condensed in a Condenser and recycled to where it was heated.  This is known as a Rankine cycle – as shown in the figure. 5 VANITA N THAKKAR BIT, VARNAMA A machine that transforms energy from thermal or pressure form to mechanical form; typically an engine (A mechanical device used to produce rotation to move vehicle or otherwise provide the force needed to generate kinetic energy.) or turbine (any of various rotary machines that use the kinetic energy of a continuous stream of fluid - a liquid or a gas - to turn a shaft). A device that converts mechanical energy to electrical energy, generally using electromagnetic induction.
  6. 6. MORE ABOUT RANKINE CYCLE  The Rankine cycle is a thermodynamic cycle which converts heat into work.  The heat is supplied externally to a closed loop, which usually uses water as the working fluid.  This cycle generates about 80% of all electric power used throughout the world, including virtually all solar thermal, biomass, coal and nuclear power plants.  It is named after William John Macquorn Rankine, a Scottish polymath. 6 VANITA N THAKKAR BIT, VARNAMA G4
  7. 7. Slide 6 G4 A polymath (Greek polymathēs, πολυμαθής, "having learned much") is a person whose expertise fills a significant number of subject areas. In less formal terms, a polymath (or polymathic person) may simply refer to someone who is very knowledgeable. Guest, 01-01-2002
  8. 8. WILLIAM RANKINE  The Rankine Cycle is named after William Rankine. Trained as a civil engineer, William Rankine was appointed to the chair of civil engineering and mechanics at Glasgow in 1855. He developed methods to solve the force distribution in frame structures.  He worked on heat, and attempted to derive Sadi Carnot's law from his own hypothesis. His work was extended by Maxwell.  Rankine also wrote on fatigue in the metal of railway axles, on Earth pressures in soil mechanics and the stability of walls. He was elected a Fellow of the Royal Society in 1853.  Among his most important works are Manual of Applied Mechanics (1858), Manual of the Steam Engine and Other Prime Movers (1859) and On the Thermodynamic Theory of Waves of Finite Longitudinal Disturbance. 7 VANITA N THAKKAR BIT, VARNAMA
  9. 9. PROCESSES IN RANKINE CYCLE There are Four processes in the Rankine cycle, each changing the state of the working fluid.  Process 1-2: Working fluid is PUMPED from low to high pressure, as the fluid is a liquid at this stage the pump requires little input energy.  Process 2-3: The high pressure liquid enters a BOILER where it is heated at constant pressure by an external heat source to become a dry saturated vapour (or wet vapour).  Process 3-4: The dry saturated vapour expands through a TURBINE, generating power. Due to decrease in temperature and pressure of the vapour, and some condensation may occur.  Process 4-1: The wet vapour then enters a CONDENSER where it is condensed at a constant pressure and temperature to become a saturated liquid. The pressure and temperature of the condenser is fixed by the temperature of the cooling coils as the fluid is undergoing a phase- change. 8 VANITA N THAKKAR BIT, VARNAMA
  11. 11. RANKINE CYCLE : PRACTICAL CARNOT CYCLE  The Rankine cycle is sometimes referred to as a Practical Carnot cycle as, when an efficient turbine is used, the TS diagram begins to resemble the Carnot cycle.  The main difference is that a pump is used to pressurize liquid instead of gas. This requires about 1/100th (1%) as much energy than that in compressing a gas in a compressor (as in the Carnot cycle). 10 VANITA N THAKKAR BIT, VARNAMA
  12. 12. Actual Rankine Cycle: 11 VANITA N THAKKAR BIT, VARNAMA
  13. 13. Rankine Cycle with Reheating Rankine Cycle with Regeneration 12 VANITA N THAKKAR BIT, VARNAMA
  16. 16. MAJOR CIRCUITS IN TPP : Layout of Thermal power plant can be divided in 4 circuits : 1. Coal and Ash Circuit 2. Air and Gas Circuit 3. Feed Water and Steam Circuit 4. Cooling Water Circuit 15 VANITA N THAKKAR BIT, VARNAMA
  17. 17. POINTS FOR SITE SELECTION OF TPP 1. Availability of Fuel: 400MW power plant required 5000 to 6000 tons of coal per day 2. Ash Disposal Facilities: ash generated is 20 to 40 % of coal used. Ash comes out is very hot and very corrosive in nature. Also it is very hazardous to atmosphere and human health. 3. Nature of Land: Land must have sufficient bearing capacity to withstand dead load of plant and vibrations of machines. 4. Availability of Water: 60 MW Power Plant required 20 to 30 thousand tons of cooling water and 500 to 600 tons of makeup water per hr. 16 VANITA N THAKKAR BIT, VARNAMA
  18. 18. 5. Space Requirement: 3-5 acres land required per MW. Mostly for coal storage and ash handling and another utilities. 6. Transport Facilities: Location should be near to river or sea to get cheapest transportation of coal by ship or it should be located near railway track for another cheaper option. Road transport is costlier then other means. 7. Availability of Labor: Cheap labor should be available. 8. Public Problems: Power Plant should away from town or city to avoid nuisance from fly ash, coal dust, smoke and heat discharge from plant. 9. Size of the Plant POINTS FOR SITE SELECTION OF TPP (CONTD.) 17 VANITA N THAKKAR BIT, VARNAMA
  19. 19. THANKS !!! -VanitaThakkar Associate Professor, Mechanical Engineering Department, Babaria Institute ofTechnology,Varnama, Vadodara 18 VANITA N THAKKAR BIT, VARNAMA