Thermal Power Station

BLOCK DIAGRAM OF THERMAL POWER PLANT

Overview of coal handling plant Wagon tippler Raw coal from bharat coal ltd. Dhanbad & bilaspur(MP) To SSTPS from gudla via a single railway track bunkers hoppers Crusher house Coal mills (pulverization) Raw coal feeders Boiler furnace ( tangential firing of pulverized coal)

Steam Boiler 1.The utility boilers are large capacity steam generators used for the electrical power generation. 2. In boiler heat energy is released from the combustion of fossils fuel and heat is transferred to different fluids in the system. 3. The boiler installed in S.T.P.S. are single drum, tangential fired water tube naturally circulated over hanged, pulverizing coal firing with a max. Continuous steam output of 375 tons/hour at 138 kg/cm2 pressure and 5400C temperature. 4. Heat transfer section in boiler 4.1 Furnace : Furnace is the primary element part of the boiler where the chemical is obtained by combustion.

Air from environment via draft fans BOILER: stack Flue gases DM water Boiler water tubes & various stages Super heated steam Boiler furnace Air from environment via draft fans Ash handling plant Pulverized coal

2.The major fuels used in the steam generation are coal oil and gas. 3. In furnace the whole combustion region is surrounded by tubes through which water flows. BOILER AUXILLARIES 4.2 SUPER HEATER: Superheats are meant to raise the tem. of steam by absorbing heat from flue gases steam them. 2. Super heater eliminates the formulation of condensate during transporting of steam in pipelines and inside the early stages of turbine, which is harmful to the turbine blades and pipelines . 3. Superheated steam is led into the H.P. turbine through main steam stop valve. After doing the useful works in the H.P. turbine the

steam is returned to reheater through the cold reheat lines. 4. The superheataer may be made in the form of coils and platens. 4.3 Reheater: Reheater are used to raise the temp. of steam from which point the energy had been extracted in H.P. turbine with increasing no. of reheating stages. Reheating is continuing till temp. of steam is reaches to 5400C. 2. Superheaters and reheaters tubes are made of 50 to 75 mm outside diameter. 4.4 Economizer : The function of an economizer in a steam-generating unit is to absorb heat from the flue gases and add this as sensible heat to fed water. It acts like feed water heater.

The size of economiser tubes are 45 to70mm in outside diameter . The water flow must be uniform to avoid the steam formation in economiser. 4.4Air Preheater:Air preheater is a heat exchanger in which preheating of air done by transferring heat from the flue gas before supplying to the combustion chamber.For better combustion the air temp.250to350 is always desired . The preheating of air results: 1.Improved combustion 2.Saving in fuel consumption 3.Thermal efficiency.

Super heaters & reheater Flow of steam turbine Boiler drum Boiler tubes Super heaters & reheater condenser economiser FWP DM water plant

Steam turbine Turbine is a prime mover in which a shaft is rotate by impact or reaction of stream of working substance ( steam, water, gases etc) upon blades of a wheel. It converts the potential or kinetic energy of the working substance into mechanical power by dynamic action of working substance. When the working substance is steam it is called the steam turbine. There are no. of blades alternatively fix & rotate due to which velocity is increased & pressure is decreased. Principle of operation : . The steam is caused to fall in pressure in a passage of nozzle: doe to this fall in pressure a certain amount of heat energy is converted

In to moving with a greater velocity. The rapidly moving particles of steam suffer a change in direction of motion which gives change of momentum and therefore to a force. IMPULSE TURBINE: The passage of steam through moving part of turbine in such a manner that the pressure at the outlet side of the blade is equal to that at the inlet inside. Such a turbine is broadly termed as impulse turbine. IMPULSE REACTION TURBINE: Pressure of the steam at outlet from the moving blade may be less than that at the inlet side of the blades; the drop in pressure suffered by the steam during its flow through the moving causes a further generation of kinetic energy within the blades and adds to the propelling force which is applied to the turbine rotor. Such a turbine is broadly termed as impulse reaction turbine.

MOVING BLADES

Inlet Guide Vanes

FIXED BLADES

Rotor Layout

High pressure turbine: The HP turbine consists of 25 reaction stages High pressure turbine: The HP turbine consists of 25 reaction stages. The moving and stationary blades are inserted into appropriately shapes into inner casing and the shaft. Intermediate pressure turbine: The steam from HP turbine after reheating enters the inner casing from above and below through two inlet nozzles. The IP turbine consists of 20 reaction stages per flow. The moving and stationary blades are inserted in appropriately shaped grooves in shaft and inner casing. Low pressure turbine: Steam admitted to LP turbine from IP turbine flows into the inner casing from both sides through steam inlet nozzles.

GENERATOR: TWO POLE TYPE; WITH CYLINDRICAL ROTOR ELECTRICAL ENERGY TWO POLE TYPE; WITH CYLINDRICAL ROTOR BASIC PRINCIPLE :FARADAY’s LOW OF MAGNETIC INDUCTION COOLING: STATOR WINDING-DIRECT WATER COOLING ROTOR WINDING – HYDROGEN COOLING MECHANICAL ENERGY

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