Air Pollution CLASS Nov'08

8/13/2019 Air Pollution CLASS Nov'08

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Air Pollution


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What is Air Pollution?Contamination of theair by noxious gasesand minute particlesof solid and liquidmatter (particulates)in concentrationsthat endanger health

Lower atmosphere extends to about13km above thesurface of the earth


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Causes and SourcesMajor CausesHigh rate of population growth

UrbanisationRapid industrialisation

Transportation

SourcesNatural SourcesMan Made Sources


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Composition of Atmospheric AirClean dry air contains by volume

Nitrogen ~ 78.1%Oxygen ~ 20.9%Other gases including CO 2 , Helium,Argon, Neon, Krypton, Nitrous Oxide

etc ~ 1%


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Categories of Air PollutionPersonal exposure of an individual todust, fumes, and gases

Occupational exposure of an individualto aerosols, vapours, and gases in harmfulconcentrations in their working or occupationalenvironment

Community pollution from a variety ofsources and factors which cause adversesocial, economic, and health effects on mans total environment


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Natural SourcesPollutants includeOxides of nitrogen from electrical stormsHydrogen flouride and hydrogen chloridefrom volcanic disturbancesSulphur dioxide, hydrogen sulphide etc fromvolcanoes or from the action of sulphidebacteriaOzone formed photo chemically or fromelectrical dischargesCarbon monoxide from atmosphericoxidation of methane and formaldehyde


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Natural SourcesDust, aerosols, and suspended particulatematter (SPM) from natural sourcesconsisting of

salt particles from sea waterairborne particles from soil and vegetationdust of meteoric originbacterial spores, and pollen

dust, ash, and gases from volcanic actiondust from dust stormssmoke of forest firesmineral particles from erosion of rocks


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SPM and AerosolsSPM

consists of all atmospheric particles, eithersolid or liquid, dispersed in a gaseousmedium

Aerosolsrefer to the dispersion of solid or liquidparticles of microscopic size in a gaseousmedium such as smoke, fog, mist etc(generally solid and liquid particles in thesize range 100 microns down to 0.01microns or less)


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Types of AerosolsDust solid particles larger than colloidal particlesthat are capable of temporary suspension in air or othergases (size range ~ 1 to 200 microns)

Smoke finely divided particles resulting fromincomplete combustion or other chemical processes predominantly carbon particles (~


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Natural SourcesRadioactive natural sources consistof radioactive minerals in the

earths crust (derived from theuranium series, thorium series,and the actinium series) and thosegenerated by the action of cosmicrays from the outer space on thegaseous constituents of theatmosphere (radon and thoron)


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Natural SourcesAtmospheric ReactionsNatural chemical reactions taking place in the loweratmosphere convert gases or vapours into solids andliquid products by oxidation, condenstion, andpolymerisation mechanismsIn the upper atmosphere, photochemical reactionsmay break down complex molecules by absorption ofhigh energy UV solar radiation and resultantoxidation and other reactionsCarbon dioxide gas is released by all forms of lifeduring respiration


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Man Made SourcesProducts of combustion of fuel in housesExhaust gases from automobiles

Industrial activities eg. Metal smelting,refining, iron and steel manufacture, oilrefining, chemical and petrochemicaloperations, manufacture of pulp and paper

An estimate of dust fall in the mostcontaminated areas - ~ 50 to 100tons/sq.km/month


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Man Made SourcesSulphur Dioxide

Thermal Power stations are the main source

- ~ 40% of the total emissionAnnual contribution from combustion of coaland petroleum products - >20 M tons/yr

Nitrogen Oxides

Combustion of fuelsMajor contributor- automobilesOthers include thermal power stations,industries, households etc


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Man Made SourcesCarbon Monoxide

Exhaust of automobiles and coal burningIncomplete combustion of carbanaceous fuels~ 500 M tons/yr

Hydrocarbonsfrom automobile exhausts, smoke of incinerators,from oil refineries etc

Photochemical OxidantsAldehydes

from the combustion of fuel


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Classification of PollutantsPrimary pollutants

Emitted directly from identifiable sourcesPollutants from natural or anthropogenic sources in theatmosphereIncludes particulate matter, suplhur oxides and sulphurcompounds, nitrogen oxides, CO, compounds ofhalogens, radioactive compounds, photochemicaloxidants, hydrocarbons etc

Secondary pollutants

Formed as a result of the interaction between two ormore primary pollutants or by reactions with normalatmospheric constituents generally chemicals veryharmfulSulphuric acid, ozone, photochemical smog, peroxyacetyl nitrate


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Sources of Outdoor AirPollution

Combustion of gasoline andother hydrocarbon fuels incars, trucks, and airplanes

Burning of fossil fuels (oil,coal, and dinosaur bones)InsecticidesHerbicidesEveryday radioactive falloutsDust from fertilizersMining operationsLivestock feedlots
http://www.dec.state.ny.us/website/dar/baqs/micro/pictures/phosphte.jpg


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SmogSynchronym of smoke and fogTypes

Photochemical

Air stagnation, abundant sunlight, high concentrations ofhydrocarbons and nitrogen oxides in the atmosphereOccurs in metrosFirst observed in LA in the 1940sCaused by the interaction of some hydrocarbons and

oxidants under the influence of sunlight giving rise to thedangerous peroxy acteyl nitrateCoal induced

From burning coal smoke, flyash, suplhur compoundsOccurs in cold climate when calm meteorological

conditions prevail


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Whats in Smog

particulates(especially lead)

hydrocarbonsnitrous oxidespotassiumcarbon monoxide

peroxy acetyl nitrate(PAN)other toxic chemicals


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Ill-effects of SmogPhotochemical Smog

Coughing and soar throatIrritation of eyes

Kills leaf tissuesReduces visibilityDegrades rubber, cellulose etc

Coal-induced SmogProlonged exposure may cause high mortality rateamong elderly people and those having heart andlung diseases like chronic bronchitis, asthma,broncho-pneumonia etcSmog in London on 8 th December, 1952 more than4000 people died due to suffocation


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Sources of Indoor AirPollution

Efficient insulationBacteriaMolds and mildewsVirusesanimal dander and cat salivaplantshouse dustMitesCockroachespollen
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Effects on the EnvironmentAcid rainOzone layer depletion

Global warmingIn human populationrespiratory problems,allergies, and a riskfor cancer


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Acid raincontains high levels ofsulfuric or nitric acidscontaminates drinkingwater and vegetation

damages aquatic lifeerodes buildingsAlters the chemicalequilibrium of some soils


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Status of Particulate Emission


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Effects of Air Pollution

Effect on VegetationSO 2 severely damages sensitive vegetation

Effect on Human HealthIn moderate climates and low altitudes,excess mortality has been noted amongpeople with pulmonary and cardiac

problems when SO 2 and SPM concentrationsare highAlso affects visibility in warmer climates


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Effects of Air PollutionCO combines with haemoglobin ofblood, when inhaled, and impairstransfer of oxygen to tissues - ~20%carboxyhaemoglobin may causeheadache and lassitude and impairperformance high levels also affectthe cardiovascular systemNO 2 respiratory system diseasesPhotochemical oxidants asthma,irritation of eyes, nose, and throat


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Effects of Air PollutionEffects on Physical Properties of theAtmosphere

First indication Decrease in Visibility

Also, observations of visibility in polluted areas showstrong directional variations due to scattering andabsorption of light by particles suspended in air, visibilityis lower in the direction of the sunOther meteorological factors such as inversion, RH, windspeed and height also affect visibility

Visibility depends ontransmission of light through the atmosphereability of the eye to distinguish an object (based oncontrast)

Reduced visibility is related toSizeConcentrationphysical characteristics of the particulate matter in air


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Effects of Air PollutionAffects solar radiation in urban areas, therebyaffecting the urban atmosphere and weather

Solar radiation may be reduced by ~ 30%

City may be 5-10% more cloudy, 100% morefoggy in winterFog remains for much longer durationFrequency of occurrence of fog increase

Affects atmospheric constituentsSteady increase in atmospheric CO 2Increase in lead concentration


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Effects on MaterialsMechanisms by which pollutants

deteriorate materials includeAbrasionDeposition and removalDirect chemical attack

Indirect chemical attackCorrosion


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M l i l P


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Meteorological ParametersInfluencing Air Pollution

DispersionPrimary Parameters

Wind Direction and SpeedTemperatureAtmospheric StabilityMixing Height

Secondary ParametersPrecipitation

HumiditySolar RadiationVisibility


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Temperature InversionEffective dispersion of pollutants in theatmosphere depends primarily on

the degree of stability of the atmosphere depends on the rate of change of ambienttemperature with altitudeIn well mixed dry air in the troposphere upto about10kmVertical temperature gradient or normal

environmental lapse rate is -6.5 o / 1000m

R is the gas constantfor air

n ~ 1.23 R g

nn

mC

dZ dT 1

1000

5.6 0


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Temperature Inversion

Above the troposphere isthe stratosphere. The

lower part of it hasconstant temperature(n=1) while in the upperregion temperature riseswith altitude


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Lapse Rate

AdiabaticThe lapse rate of a parcel of dry air as it

moves upwards in a hydrostatically stableenvironment and expands slowly to thelower environmental pressure without heatexchange

This is given by

mC

dZ dT

1000

86.9 0


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Lapse RateSuper adiabatic

The prevailing lapse rate or ambient lapse rate orenvironmental lapse rate is greater than the dry

adiabatic lapse rateThe rising parcel of air, cooling at adiabatic rate, willbe warmer than and less dense than the surroundingenvironmentOn a clear summer day, as a result of rapid heatingof the air near the surface of the earth, it becomesmore buoyant and moves upward resulting ininstabilityMarked vertical mixing and rapid dispersal ofpollutants


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Lapse RateSub adiabatic or Negative

Environmental lapse rate is less than the dryadiabatic lapse rate

A rising parcel of air becomes cooler and more densethan the surroundings and tends to fall back to itsoriginal positionThe atmospheric condition is stableA dense cold stratum of air at ground level getscovered by light warmer air at higher levelInversion phenomenon vertical air movementstops and pollution is concentrated beneath theinversion layer, vertical mixing of pollutants beingrestrained occurs in winter and autumn


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InversionRadiation inversion

Occurs at night, resulting from the normal dirunalcooling cycle

After sunset, ground looses heat by radiation and coolsthe air in contact with it, setting up a temperatureinversionMore common in winterInversion is destroyed next morning

Subsidence inversionThe most common type occurring at modest altitudesand often remains for several daysAssociated with subtropical anticyclones (high pressurearea surrounded by a low pressure area)


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InversionAir is warmed by compression as it descends in ahigh pressure system and achieves a temperaturehigher than that of the air belowInversion occurs if temperature increase is sufficientAir circulating around the area descends slowlyacting as a lid to prevent upward movement of thecontaminantsInversion height ranges upto ~ 1600mExtreme pollution reported when this is around200m

Double inversionOccurs when the above two occur simultaneously


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Plume BehaviourPlume Path taken by continuous discharge ofgaseous effluents emitted from a stack orchimneyShape of the plume and the concentrationdistribution of gaseous plumes depends onlocalised air stability


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Plumes

Looping Plume A common type of plumebehaviour that occurs under super-adiabaticlapse rate conditions with light to moderatewind speed on a hot summer afternoon whenlarge scale thermal eddies are presentWavy behaviour as it occurs in a highlyunstable atmosphere

High turbulence helps in rapid dispersion ofthe plume; however high concentrations mayoccur close to the stack if the plume touchesthe ground


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Plumes

Coning Plume occurs on a cloudy dayor nights with strong winds when the lapserate is near neutralPlume shape is vertically symmetrical aboutthe plume lineThe plume reaches the ground at greaterdistance than with looping


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Plumes

Fanning Plume occurs under extremeinversion conditions in the presence of lightwindMost of the vertical dispersion is suppressedby extremely stable condition and the flumefans out in the horizontal directionStrong concentrations are exhibited at plumeheight, downwind of the stackOften observed in the early morning at allseasons and at a height


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Plumes

Lofting Plume Occurs when there existsa strong super adiabatic lapse rate above asurface inversion.Downward motion and mixing is prevented bysurface inversionUpward mixing will be quite turbulent andrapid

Emission will not reach the ground surfaceThis is one of the major goals of tall stackoperation


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PlumesFumigating Plume A bad case ofatmospheric dispersionConditions for this are just the inverse of that for alofting plumeIt occurs when an inversion layer exists at a shortdistance above the top of the stack and super-adiabaticconditions prevail below itThe pollutant cannot escape above the top of the stackand they are brought down rapidly near ground due toturbulence in the region above the ground and belowthe inversionThis condition is generally of short duration ( ~ 30minutes)It is favoured by clean skies and light windsMore common in summer


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Plumes

Trapping Plume bad condition fordisperion

The plume is caught in between two inversionlayersThe plume can neither go up nor downDiffusion of the effluent will be severely

restricted to the unstable layer between thetwo stable regions


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Air Pollution Control Methodsand Equipment

Proper planning of industrial areas (eg.Zoning)Dilution of source discharge using tallstacksSource correction methods like

Changes in raw materialsProcess changes

Modification or replacement of equipmentUsing controlling equipments to reducepollutant discharge at the source


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Industrial ZoningAir pollution control - lack of proper planningduring urbanisation and industrialisation is a major problem

Exclusive Zoning System allows onlycompatible uses within each zone, excluding all other uses(eg. a separate zone is set aside for industries residentialand industrial areas in a city are not located too close toone another green belt in between them etc)

Zoning for IndustriesBased on functional requirement inter industrylinkages, railway sidings etcBased on performance characteristics trafficcongestion; hazardous nature; industrial nuisance suchas dust, noise, smoke, odour, heat, fire etc. Relativelyneat industries are kept away from other industries


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Industrial ZoningFactors to be considered

Type of industry or factoryFactory size

No. of workersDistance over which nuisance produced would besevere

ClassificationGroup I small industries which can be located inthe fringes of towns or citiesGroup II cottage and small scale industriesindulging in artistic or creative production may belocated within the town/cityGroup III industries with high pollution potential


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Industrial Zonation inIndia

Varies from city to cityDelhi 6 zones with no provision for heavy

and large industries in the urban areasBombay 4 zones small repairing and lightmanufacturing units (permitted even inresidential areas), service industrial zone,

special industrial zone, and general industrialzone

Bangalore Light, medium, and heavy


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Stack DesignFor a continuous single emission source, based onFicks Law, the concentration of the pollutant forturbulent transport of gas or aerosols (< 20 microns)is given by

If the ground level concentration is required only inthe downwind horizontal direction (y=0)

222

2

1

2

12

1

,,, 2 Z Z y

H z H z y

z y

H z y x eeeuQ

C

2

2

1

,0,0, 2

Z

H

z y

H x euQ

C


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Stack DesignC = concentration of pollutant (g/cu.m)Q = Pollutant emission rate (g/s)u = mean wind speed (m/s) at height h

H = effective height of stackx, y = downwind and crosswind horizontal distances(m)z = level of computation of concentration (m) are plume standard deviation in crosswindand vertical direction respectively (m)

y y and


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Stack DesignGraphical profile of ground levelconcentrationMaximum ground levelconcentration (~ at a distance 5 to10 times the stack height) shouldbe substantially below therequirement of ambient air qualityOtherwise, stack height has to beincreased

xwitht consis provided H when

H euQ

C

y

z z

y

z H x

tan,2

22,,0,0,max


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Stack DesignObjectives of Stack

To prevent reentry of smoke into theindustry/ factory building

To provide natural draft for combustionTo disperse the pollutant into theatmosphere

Ratio of stack exit velocity to wind velocity >1.5 to allow effluent to break cleanly from thestack and prevent downwashHeight of the stack ~ 2.5 times the height ofthe surrounding building


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Stack Height Indian Practice

Values obtained using the above equations shallbe subject to the following minimum values

Chimneys for industries in general (except TPS) - 30mFor TPS upto 500 MW capacity - 220mFor TPS >500 MW capacity - 275mFor boilers generating steam @less than 2t/h- 9mFor boilers generating steam @ >30t/h- 30mFor boilers of intermediate capacity- 9 to 30m

For DG sets, minimum stack height shall be 1.5 to3.5m more than the height of the building and shall beworked out as

h=h +0.2 (capacity in KVA)Where h= height of building


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Briggs Formula

IS: 8829-1978For hot effluents with heat release of

the order of 106 cal/s or more

mrise plumeh

sm speed wind u

m stack of height h

scal inreleaseheat Qu

Qhh

H

H

/

/

09.04.1284.04

1


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Briggs Formula

For not very hot releases

mdiameter exit stack d

smvelocityaffluxV u

d V h

/

3

0

0


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Data For Stack DesignGas temperature and pressure rangeRate of emissionType of emission such as dust, fume, mist, gas etcConcentration of pollutantDischarge velocity of stackComposition of gasParticle size distributionVertical temperature profileMean mixing depth

Stability classDirection and velocity of windRelationship of stack to adjoining structuresDraft required at the flue opening to the stack


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Control by source correction

Change in raw materialseg. Low sulphur fuel in place of high sulphur fuelRemoval of non essential ingredients (for the process)

which may be contributing to pollutionProcess modification

eg. Use of exhaust hoods and ducts over some types ofindustrial ovens recovery of solvents that could havebecome pollutants

VOC recoveryEquipment modification or replacement

Replacement of old equipment by new equipmentProper maintenance of equipment


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INTRODUCTION TOAIR POLLUTION CONTROL


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Air Pollution Control Equipment

While selecting the device for a specificproblem, look at

Carrier gas characteristics pressure, dew

point, density, viscosity, temperature etcOperational factors head room, floor space,corrosion service requirement etcProcess factors allowable pressure drop,gas flow rate, collection efficiency

requirement, allowable pressure drop etcParticulate characteristics shape, density,stickiness, corrosiveness, size, toxicity,electrical conductivity etc

IMPORTANT PROPERTIES


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IMPORTANT PROPERTIESPARTICULATE CONTROL

Size

VolatilityShape/texture

ConcentrationGas flow

G ll


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Gaseous Pollutants

Adsorption Absorption Condensation Combustion


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Dust collection devices

Divided into three categoriesbased on collection efficiency,

capacity, and operation modeInternal SeparatorsWet collection devicesElectrostatic precipitators


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Internal Separators

Manufactured in various sizes andshapes

Common typesLouver collectorFabric filter

Gravity settling chamberCyclone


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Louver Separator

Principle - Suddenchange in the direction of gasstream higher inertia ofdust particles cannotsuddenly change direction dust is separated outConsists of several blades setat angles to the flow path ofthe gas stream which forcesa quick change in thedirection of the gas streamDust particles separated outand collected in the bed ofthe collectors bottom

Fabric Filters


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Particulates

Gas InflowGas Inflow

Gas Outflow

Particulates

Filter Bags


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Fabric FiltersAn important parameter in design air tocloth ratio

Low ratio bag filters 7 to 25

High ratio bag filters 25 to 50Dust laden gas enters through the bottom ofthe hopper heavy particles settle due togravity particles are deposited on the inner

side of the fabric when gas passes throughthem cleaning by passing compressed air inthe opposite directionFabric Nylon, Teflon, Nomex, Dacron, Wool,

Glass etc

b l


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Fabric FiltersADVANTAGES/DISADVANTAGESAdvantage s :- High collection efficiency- Operation for variety of dust types

- Modular in design- Operates over wide range of flow rates- Reasonably low pressure drop

Disadvantages :- Large floor areas- Fabrics harmed by high temps, corrosive chemicals- Cant operate in moist environment- Potential for fire or explosion


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Gravity Settling Chambers


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Gravity Settling ChambersAn enclosed chamber wherein the velocity ofthe dust laden gas is considerably reduced particles settle by gravity

Horizontal gas velocity may be kept as low aspossible to allow streamlined flowGas velocities ~ 0.30 to 3 m/sParticles coarser than 40 microns settle in thisrange


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CycloneWorks on the principle of separating the particles fromthe gas by transforming the inlet gas velocity into adouble vortexThe gas entering the cyclone spirals down the innersurface and then spirals up at the central portion of thecycloneDust particles tend to concentrate on the surface of thecyclone wall due to inertia and are led to the receiverEfficiency increases with

Inlet velocity of the dust laden gas when there is noagglomerationDiameter of the dust particleDensity of the dust particlesDust concentration in the gasSmoothness of the inner wall of the cyclone


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Cyclone


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CYCLONE


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CYCLONEADVANTAGES/DISADVANTAGES

Advantages:- Less expensive- No moving parts- Withstand harsh conditions- Can operate in a wide range of conditions

Disadvantages:- Only moderately efficient- High operating costs due to pressure drop


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Wet Collection DevicesRemoves dust particles from gas by wettingparticles with a liquid droplet diffusion orcondensation or impinging the wetted or

unwetted particles on a collecting surface andthen cleaning them by a flush of liquidCommon wet collection devices

Cyclonic scrubbers

Spray chambersVenturi scrubbersPacked towers


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Cyclonic ScrubbersAlso called wet cyclonesGenerally, particulate matter is seperatedusing centrifugal force and impingement ofwater at the entranceThe moisture elimination section consists ofzig-zag platesWater requirement ~ 2 to 50 l/ 40l of gasGas flow rate ~ 2000 l/minRemoval particles of size 5 microns andabove


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WET SCRUBBERS


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ADVANTAGES/DISADVANTAGES

Advantages:- Handle flammable and explosive dust- Gas absorption and dust collection

- Handle mists- Cooling of hot gases- Handle corrosive gases and dust

Disadvantages:- High corrosion potential- Liquid waste stream- Freezing protection needed- No recycling of particulate- High energy costs


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Venturi ScrubbersCan clean about 4000 lof gas/minConsists of a venturithroat through whichcarrier gas pushes at avelocity of 3400 to12600 m/minThe scrubbing liquid,usually water is added inthe direction of flow ofgas at the throat at therate of ~ 0.3-1.5 l/ l ofgasEfficiency can be as highas 99%


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Packed TowersFor cleaning air and gasesDust laden gas is passed upward through thebed of the collecting materialLiquid flows down through the bed, keeping itclean, and preventing re-entrainment of thedeposited particlesCollecting surface area should be largeMaterials used in the collecting surface shouldhave low density, resistant to corrosion, andchemically inertPressure drop remains constantSludge shall be properly disposed of


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Electrostatic PrecipitatorCan be applied to a great variety of problems withefficiencies as high as 99.99%Capacities upto about 2,00,000 l/min

Temperatures upto 600 deg CPressure drop is very low ~ 6 to 10 mm of waterDirty gas is allowed to pass through narrow, vertical gaspassages formed by parallel rows of grounded collectingelectrodes

Electrically insulated high voltage wires are spacedprecisely on the centre lines of each passage therebycausing dirt gas to pass between the high voltage wiresand the grounded plates


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Electrostatic PrecipitatorOperational principle

Ionisation of gasDust charging dust particles get negatively chargedbecause the negatively charged ions collide withthemPrecipitation of dust negatively charged dustparticles are driven by electrical forces to thepositively charged grounded plate and held to them goes on accumulating to form a thick layerAs the thickness of the dust layer increases more

than 6mm, electrical attraction becomes weak efficiency of the ESP comes down a sharp rapcauses the dust layer to shear away agglomeratesare collected in hoppers


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Electrostatic Precipitator

Electrostatic Precipitators


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Particulates

Particulates

Electric Plates

Gas InflowGas Outflow

ESPsADVANTAGES/DISADVANTAGES


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ADVANTAGES/DISADVANTAGES

Advantages:- High efficiencies for small particles- Large gas volumes with low pressure drops

- Dry collection of valuable materials- Wet collection of fumes or mists- Low operating costs

Disadvantages:

- High capital costs- No control of gaseous emissions- Inflexible to changing operating conditions- Large space requirements- Resistivity problems

EFFICIENCY


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PARTICULATE CONTROLS

EFFICIENCY (%)CONTROL 5 m 2 m 1 m

CYCLONE (MED EFF) 30 15 10CYCLONE (HIGH EFF ) 75 50 30ESP 99 95 85

BAGHOUSE 99.8 99.5 99SCRUBBER 99.7 99 97

AIR POLLUTION CONTROL


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AIR POLLUTION CONTROLGASES AND VAPORS

SO X, NO X, VOCs, HAPs, CO

VOC methods - function of inlet VOC

concentration- Thermal incineration- Catalytic incineration- Carbon adsorption w/ incineration- Condensation- Absorption


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SO x CONTROL METHODS

Desulfurization (Coal cleaning) Low sulfur fuel

Flue gas desulfurization (FGD)- dry or wet processes

(activated carbon adsorption/Water absorption)

- Regenerative processes (REINLUFT PROCESS)


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SYSTEM DESIGN FACTORS


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SYSTEM DESIGN FACTORSAIR POLLUTION CONTROL

Most important step is accurate source characterization!!Parameters- Pollutant concentrations- Flow rate- Temperature- Pressure- Moisture, oxygen and heat content- Corrosiveness- Explosivity- Particle size distribution- Molecular weight- Vapor pressure- Solubility- Adsorptive properties- Reactivity


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ADDITIONAL DESIGN FACTORS

Site specific- Operation schedule of source- Utilities- Space constraints- Workforce skill levels- Disposal costs and options

Waste minimization practicesCost considerations- Capital costs- Annual costs- Disposal costs- Installation costs- Testing and permitting costs

MOBILE EMISSIONS


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MOBILE EMISSIONSAIR POLLUTION CONTROL

Pollutants- Metals- Hydrocarbons- NOx- SOx- Particulates

Variety of methods- Clean fuels- Engine design- Catalytic converters- Reduction of miles traveled

Air Pollution CLASS Nov'08

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Transcript of Air Pollution CLASS Nov'08