Summer Training Report

@CTPS Rohit anand 10bme0153 4th semester VIT VELLORE

CONTENTS

About the company Introduction General layout Components Coal cycle Condensation cycle Steam cycle Power cycle Ash treatment exhaust

About The Company

• Damodar valley corporation, popularly known as DVC , came into being on July 7, 1948.this was first multi-purpose river valley project of independent India.

• CTPS: chandrapura thermal power station is situated in Bokaro district of Jharkhand. This has a installed capacity of 1600 MW.

MISSION • To generate adequate and

reliable power most economically , efficiently and eco-friendly.

• To spearhead accelerated power development by planning and implementing new power projects

VISION• To be the best power utility

in the country and one of the best in the world.

INTRODUCTION• A thermal power plant converts the heat

energy of coal into electrical energy. Coal is burned in a boiler which converts water into steam. The expansion of steam produces mechanical power drives alternator coupled to turbine

COMPONENTS main Coal mill Boiler Turbine Generator Condenser super heater

auxiliary• FD fan• ID fan• Safety valve• Gauge valve• Conveyer• Transmission lines• Air pre-heater• De-aerator• Reheater• ESPs

COAL CYCLE

Coal stock yard

Coal conveyer

Coal hopper

Coal mill

furnace

Coal Handling Plant Wagon unloading system Crushing system Conveying systemUnload the coal from wagon for standardization and selection and then the coal is stored in STOCK YARD.Through conveyer system , the coal is sent in hopper.Hopper allows to pass coal pieces<200 mmFrom it coal falls on vibrator which is supported by roller

Crushing System

• The gear box: contains worm wheel and worm gear which moves the wheel.

• Motor: this provides energy for both worm gear and exhaust fan to move.

• Exhaust fan: it sucks the coal dust , mixes it with pre-heated air (to maintain coal temperature) and send it through pipes in to boiler.

• One coal mill unit sends 8 pipes into boiler.• Grinding roll fixed with mill body as shown in fig.

brings coal to 20 mm size.

Coal + Air SupplyAtmospheric air

Combustion intake

Air pre heater

Fd fan

Coal pulveriser

Coal +air

Burner floor Primary superheater

Air Supply DRAFT SYSTEMNatural MechanicalIn mechanical systems fans are used to create draft .

At CTPS balanced draft system is used in which both FD and ID fans are used

• FD fan-forced draft fan , this creates a negative pressure in the boiler and via this pressure difference atmospheric air is drawn in the boiler

• ID fan-this sucks the treated flue gas out and ejects it through chimney.the mechanical draft is created by fan

• Now the pre heated air goes into coal pulverizer and then sent into burner floor of boiler where through corner firing system(CFS) fire balls are made , which burn the coal laden air stream coming from below. Thus producing required heat for super heating.

Air Pre-heater

• This is a general term to describe any device designed to heat air before another process(for ex. Combustion in a boiler). The air comes through combustion intake pipeline, assisted by FD fan.

CONDENSATE CYCLEL.P. turbine

Surface condenser

Cooling tower

Condensate pump

De-aerator

Feed water heater

River water

Feed water pump

Alum house

reservoir

Water treatment

Pure water

sump

economizer

Condensate pump

Water Supply• Majority of water supply for steam generation

is condensed water. The steam fromL.P. turbine is sent into surface condenser which

• Changes the phase from steam to water.• Now, this water is sent to cooling towers

which are evaporative coolers used for cooling water. these evaporate some part of condensed water to reject heat. At CTPS cooling towers are of hyperboloid structure

DE-aerator• Device for air removal and

corrosive dissolved gases because corrosion can render pipe networks useless and rusty

Feed water heater• This is used to pre heat

water delivered to a steam generating boiler, improving efficiency. Feed water heaters allow the water to be brought upto saturatiuon temperature very gradually. This reduces costs and help prevent thermal shocks to boiler material.

•

• Feed water pump: these pumps are high pressure units that overcome steam pressure to force water into the boiler drum.

• ECONOMIZER :in boilers, these are heat exchangers that heat fluids usually water, upto its saturation point, they use the energy from the heat of flue gas and thus reduce heat in put and costs. It is placed in the passage of flue gas between outlet and chimney

Make Up Water• This is additional water added in feed water

stream . but before that it Is treated in water treatment plant

• At CTPS, there are 4 treatment units• 1)dirty water from reservoir. Sedimentation

removes majority suspensions particles: trough perforations clean water drips into well 2)

• (2) alum is mixed in 2)with water coming from 1) micelle formation and this micelle is removed by mechanical arrangement; by forcing this trough a slope.

• 3)clean water comes from 2) into (3) via perforations.

• This treated water is sent into feed stream , where it mixes with condensed water, to form “final water”.

STEAM CYCLE• fe Feed water

economizer

Boiler drum

Ring header

Water valve

Gauge valve

Ceiling tube

Boiler drum

Riser tube

Input header

Primary super heater

Secondary super heater

Platen superheater

turbine

Boiler Operations The feed water enters into economizer reaches upto saturation point. It is sent into boiler steam drum

BOILER STEAM DRUMIt is reservoirof water/steam at the top end of the water tubes in the water-tubeboiler. They store the steam generated in the water tubes and act as aphase separator for the steam/water mixture. The difference indensities between hot and cold water helps in the accumulation of the“hotter”-water/and saturated –steam into steam drum.

• The• separated steam is drawn out from the top section of the drum.• Saturated steam is drawn off the top of the drum. The steam will reenter• the furnace in through a super heater, while the saturated water• at the bottom of steam drum flows down to the mud- drum /feed water• drum by down comer tubes accessories include a safety valve, water• level indicator and fuse plug. A steam drum is used in the company of• a mud-drum/feed water drum which is located at a lower level. So that• it acts as a sump for the sludge or sediments which have a tendency to go

to bottom

Super Heater Tubes• At CTPS types of super heater are :• Primary -straight pipes• Secondary- U shaped• Platen - BENT shaped• This all tubing has same function to super heat

water: to heat the steam extracted from drum, increasing it’s thermal energy and decreasing the likelihood that it will condense in pipe network or in turbine section

• The superheated steam is sent into high pressure turbine, at 540 degree celcius and 145 kg per square cm

• And the thin ash particles are collected by ESP and thick ash fall into ash hopper below.

• Turbine section:• A steam turbine is a device that extracts thermal energy from

pressurized steam and used it to do mechanical work on a rotary output shaft. this is a form of heat engine that derives much of its improvement in thermodynamic efficiency through the use of multi stagesin expansion of steam

POWER CYCLEBoiler drum

h.p. turbine

Reheater inlet

reheater Reheater outlet

i.P turbine

l.p.turbine

Surface condener

• There are three turbines:• High pressure – 5 stages• Intermediate pressure-12 stages• Low pressure -9 stages

• Turbine types:(based on stages)• Impulse turbine: stage is set of moving blade behind the nozzle.• Reaction turbine: each row of blades is called a stage.

• Blades:• in H.P., the blading used is impulse blading because it extracts more work

from high pressure steam than reaction blading.

• Impulse blading:it is in shape of half moon. As steam impact the moving blade, it pushes the blade forward. this causes steam to lose velocity without losing pressure.

• The steam coming out from the H.P. turbine gas into reheater through inlet and comes back trough outlet attaining thermal energy can be extracted in I.P. turbine and L.P. turbine.

• I.P. and L.P. turbines: the steam at low pressure and temperature enter into this turbine pair respectively: so reaction blading is used

• REACTION BLADING: works on same concept as a jet engine. A jet engine is designed to take in air. Each moving reaction blade is designed to act as a nozzle.as the steam passes trough a reaction blade it causes the reaction blade to be propelled forward , resulting in rotation of L.P. turbine rotor

• Intercept valve: this is in H.P. turbine and governs the the steam flow amount.

• There is a surface condenser below L.P. turbine, explained in water supply previously.

• all the three turbines are mechanically linked trough a rotor and the generator is coupled at the end of the system. At CTPS it is hydrogen cooled.

Ash Treatment Plant• ESP: electro static precipitator is a particulate device that removes particles

from a flowing gas, using force of an induced electrical charge.automatic rapping systems and hopper evacuation system remove the collected particulate matter while in line allowing esps to stay in operation for years at a time.

• From the hoppers these are collected in the collector tank.• this collector tank has wet line trough which water comes.both ash and

water are mixed and sent into collector tank. the hydrovactor is vaccum creating machine, that creates vaccum by removing water and air ,thus ensuring necessary pressure difference.

• A VACCUM BREAKER is like a plate, it maintains and releases vaccum as and when required.

• The slury is sent into sump from where it is carried 4 km away from CTPS using suitable pumps and pipe network.

• There is air washer in conjunction with hydrovactor, that cleans air of its dust and susrensions, etc.

• For thick ash, metal or stones which are falling in ash hopper below,where they are crushed using grinde. Using grinder. Using a power cylinder to open the gate and remove the pulverized debris with water into sump tank and discharged.

Exhaust Cycle

Flue gas

ESP

ID fan

Flue

Ash treatment plant

exhaust• The dust and ash are taken into ash treatment

plant as mentioned earlier.• The rest flue gas moves through flue gas stack

which is a type of chimney, a vertical pipe or channel for the exhaust gas outlet.