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Steam power plantLayoutBoilersPulverized coal burnersFluidized bed combustion



Power generating unitsare mega projectsRequire huge capitalinvestmentRequire naturalresources like, fossil fuelsLarge amount of waterChanges the local ecosystemHuge Impacts on theEnvironment and Health









Surface MiningStrip Mining

Underground Mining



Air Quality Around the coal based plants the ambient concentrations ofSulphur Dioxide, Oxides of Nitrogen and SPM are high.

Epidemiological Studies have shown that of the area surroundingcoal based thermal plants, population living within a 2 -5 kmradius of the plant suffers from respiratory disorders .

Two other gases, carbon dioxide and ozone are emitted. The highamount of carbon dioxide emission from thermal power plantscontribute to global warming leading to climate change issignificant Ground level ozone, which is formed due tophotolytic reactions of NO x and its impacts are under study



Fly ash contains atoxic brew of

dangerouschemicals and is thelargest contributor

to mercurypollution



Composition of Fly ashIt contains as main chemical components SiO2

(51.4 wt%), Al2O3 (22.1 wt%) and Fe2O3 (17.2wt%; ignited weight basis). As commonlyobserved, many toxic elements and heavy metalsare highly enriched in the fly ash relative to theoriginal coal. For example, considerable amountsof Be (16.4 ppm), Cu (106 ppm), Zn (578 ppm), As(40.4 ppm), Cd (2.6 ppm), Hg (18 ppm), Pb (71ppm), and U (21.8 ppm) is found in Fly ash.



Water slurry is used to take the ash from the powerplant to the ash pond for disposal.Water slowly seeps into the ground while carryingwith it the ash leach ate. Water may contain harmfulheavy metals like boron, which have a tendency toleach out over a period of time.When fly ash comes into contact with water, leachesinto groundwater supplies which get polluted and

unsuitable for domestic use.The release of ash pond decant into the local waterbodies- water dries up, dust nuisance, increasesturbidity, decreases primary productivity, affectsfishes and other aquatic biota





Steam Turbine GeneratorIs a series of steam turbines interconnected to each other andthen a generator

Steam CondenserSteam enters from the turbine generator and is pumped into thebottom of the condenser, where pumps recycle the condensedsteam from the feedwater

StackReleases process emissions.



What is a Boiler?

Introduction

• Vessel that heats water to becomehot water or steam

• At atmospheric pressure watervolume increases 1,600 times

• Hot water or steam used to transferheat to a process



Introduction

BURNERWATER

SOURCE

BRINE

SOFTENERS

CHEMICAL FEED

FUELBLOW DOWNSEPARATOR

VENT

VENTEXHAUST GASSTEAM TOPROCESS

STACK DEAERATOR

PUMPS

Figure: Schematic overview of a boiler room

BOILER

ECO-NOMI-ZER



Types of Boilers

1. Fire Tube Boiler

2. Water Tube Boiler

3. Packaged Boiler

4. Fluidized Bed (FBC) Boiler

5. Stoker Fired Boiler

6. Pulverized Fuel Boiler

7. Waste Heat Boiler

8. Thermic Fluid Heater (not a boiler!)



Type of Boilers

1. Fire Tube Boiler

•

Relatively small steamcapacities (12,000kg/hour)

• Low to medium steampressures (18 kg/cm2)

• Operates with oil, gasor solid fuels



Type of Boilers

2. Water Tube Boiler• Used for high steam

demand and pressurerequirements

• Capacity range of 4,500 – 120,000 kg/hour

• Combustion efficiencyenhanced by induceddraft provisions

• Lower tolerance forwater quality and needs

water treatment plant



Type of Boilers

3. Packaged Boiler

OilBurner

ToChimney

• Comes in completepackage

• Features•

High heat transfer• Faster evaporation• Good convective

heat transfer• Good combustion

efficiency• High thermal

efficiency• Classified based on

number of passes



Type of Boilers

4. Fluidized Bed Combustion(FBC) Boiler

• Particles (e.g. sand) are suspended in highvelocity air stream: bubbling fluidized bed

• Combustion at 840 ° – 950 ° C• Capacity range 0,5 T/hr to 100 T/hr• Fuels: coal, washery rejects, rice husk, bagasse

and agricultural wastes• Benefits: compactness, fuel flexibility, higher

combustion efficiency, reduced SOx & NOx



Type of Boilers

4a. Atmospheric Fluidized BedCombustion (AFBC) Boiler

• Most common FBC boiler that uses preheatedatmospheric air as fluidization and combustion air

4b. Pressurized Fluidized BedCombustion (PFBC) Boiler

• Compressor supplies the forced draft andcombustor is a pressure vessel

•

Used for cogeneration or combined cycle powergeneration



Type of Boilers

4c. Atmospheric Circulating FluidizedBed Combustion (CFBC) Boiler

• Solids lifted from bed,rise, return to bed

• Steam generation inconvection section

• Benefits: moreeconomical, better space

utilization and efficientcombustion



Type of Boilers

5. Stoke Fired Boilers

a) Spreader stokers• Coal is first burnt in suspension then in

coal bed• Flexibility to meet load fluctuations• Favored in many industrial applications



Type of Boilers

5. Stoke Fired Boilers

b) Chain-grate or traveling-grate stoker

• Coal is burnt on movingsteel grate

• Coal gate controls coalfeeding rate

• Uniform coal size forcomplete combustion



Type of Boilers

Tangential firing

6. Pulverized Fuel Boiler• Pulverized coal powder blown with combustion

air into boiler through burner nozzles• Combustion

temperature at 1300 -1700 ° C

•

Benefits: varying coalquality coal, quickresponse to loadchanges and high pre-heat air temperatures





LayoutDamsSelection of waterturbinesTypes of turbines

Pumped storagehydel plants



Hydrologiccycle



Water from thereservoir flows dueto gravity to drivethe turbine.Turbine isconnected to agenerator.Power generated istransmitted overpower lines.



Hydropower

Technology

Impoundment Diversion Pumped Storage





ArchGravityButtressEmbankment or Earth



Arch shape givesstrengthLess material(cheaper)Narrow sites

Need strongabutments



Weight holds damin placeLots of concrete(expensive)



Face is held upby a series ofsupportsFlat or curvedface



Earth or rockWeight resistsflow of water





Doesn’t require dam

Facility channelsportion of riverthrough canal orpenstock



During Storage,water pumped from

lower reservoir tohigher one.Water released back to lower reservoir togenerate electricity.



Operation : Two pools of WaterUpper pool – impoundmentLower pool – natural lake,river or storage reservoirAdvantages :

Production of peak powerCan be built anywherewith reliable supply of water

The Raccoon Mountain project



Definitions may vary.Large plants : capacity >30 MWSmall Plants : capacity b/w 100 kW to 30 MW

Micro Plants : capacity up to 100 kW









Many creeks and rivers are permanent, i.e., theynever dry up, and these are the most suitable formicro-hydro power production

Micro hydro turbine could be a waterwheelNewer turbines : Pelton wheel (most common)Others : Turgo, Crossflow and various axial flowturbines



Types of Hydro Turbines:Impulse turbines

Pelton WheelCross Flow Turbines

Reaction turbinesPropeller Turbines : Bulb turbine, Straflo, TubeTurbine,Kaplan TurbineFrancis TurbinesKinetic Turbines



Uses the velocity of the water to move the runnerand discharges to atmospheric pressure .The water stream hits each bucket on the runner.

No suction downside, water flows out throughturbine housing after hitting.High head, low flow applications.

Types : Pelton wheel, Cross Flow



Nozzles directforceful streams of

water against a seriesof spoon-shapedbuckets mountedaround the edge of a

wheel.Each bucket reversesthe flow of water andthis impulse spins theturbine.



Suited for high head,low flow sites.

The largest units canbe up to 200 MW.Can operate withheads as small as 15meters and as high as1,800 meters .



drum-shapedelongated,

rectangular-sectionnozzle directedagainst curved vaneson a cylindrically

shaped runner“squirrel cage”blower

water flows through



First pass : water flows from the outside of theblades to the insideSecond pass : from the inside back out

Larger water flows and lower heads than the Pelton.



Combined action of pressure and moving water.Runner placed directly in the water stream flowingover the blades rather than striking each

individually.lower head and higher flows than compared with theimpulse turbines.



Runner with three to sixblades.Water contacts all of the

blades constantly.Through the pipe, thepressure is constantPitch of the blades -fixed or adjustableScroll case, wicket gates,and a draft tubeTypes: Bulb turbine,Straflo, Tube turbine,Kaplan



The turbine andgenerator are a

sealed unit placeddirectly in thewater stream.



Straflo : The generator is attached directly to theperimeter of the turbine.Tube Turbine : The penstock bends just before or

after the runner, allowing a straight line connectionto the generatorKaplan : Both the blades and the wicket gates areadjustable, allowing for a wider range of operation



The inlet is a scroll-shaped tube that wrapsaround the turbine's

wicket gate.Water is directedtangentially, through thewicket gate, and spiralson to a propeller shapedrunner, causing it tospin.The outlet is a speciallyshaped draft tube thathelps decelerate thewater and recover





Best suited for siteswith high flows and

low to medium head.Efficiency of 90%.expensive to design,manufacture andinstall, but operatefor decades.



Also called free-flow turbines.Kinetic energy of flowing water used rather thanpotential from the head.

Operate in rivers, man-made channels, tidal waters,or ocean currents.Do not require the diversion of water.Kinetic systems do not require large civil works.

Can use existing structures such as bridges, tailracesand channels.



Baspa II Binwa



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