cooling towers.ppt

Presentation onPresentation on

Cooling TowersCooling Towers and Their Characteristic Used in and Their Characteristic Used in

Nuclear IndustryNuclear Industry

M. Usman Shaikh, Dir HRDM. Usman Shaikh, Dir HRD

By

Cooling Towers and Their Cooling Towers and Their Characteristic Used in Nuclear IndustryCharacteristic Used in Nuclear Industry

1.1. Operating principles and basic definitionsOperating principles and basic definitions

2.2. Types of cooling towersTypes of cooling towers

3.3. Mechanical components of cooling towerMechanical components of cooling tower

4.4. Cooling water treatment and qualityCooling water treatment and quality

5.5. Cooling tower used in nuclear industryCooling tower used in nuclear industry

6.6. Comparison between nuclear and chemical Comparison between nuclear and chemical industryindustry

7.7. ConclusionsConclusions

1. Operating Principles and Basic 1. Operating Principles and Basic DefinitionsDefinitions

General operationGeneral operation

Air water contactAir water contact

Counter flowCounter flow

Cross flowCross flow

Heat Transfer Principles

Evaporation

Sensible heat

Latent heat

Cross FlowCross FlowCross flow is a design in which the air flow is directed perpendicular to the water Cross flow is a design in which the air flow is directed perpendicular to the water

flow (see diagram below).flow (see diagram below).

Counter FlowCounter FlowIn a counter flow design the air flow is directly opposite of the water flow (see In a counter flow design the air flow is directly opposite of the water flow (see

diagram below).diagram below).

Operating Principles and Basic Operating Principles and Basic DefinitionsDefinitions

Sensible HeatSensible Heat : It is amount of heat which is : It is amount of heat which is sensed by thermometer . This heat is used to sensed by thermometer . This heat is used to increased temperature of liquid.increased temperature of liquid.

Latent HeatLatent Heat : It is amount of heat which is : It is amount of heat which is not sensed by thermometer. This heat is not sensed by thermometer. This heat is used to overcome intermolecular forces of used to overcome intermolecular forces of attraction. attraction.

2. Types of Cooling Towers2. Types of Cooling Towers

General classificationGeneral classification

Types of Cooling TowersTypes of Cooling Towers Classification according to configurationClassification according to configuration

Atmospheric spray tower

Natural draft tower

Mechanical draft tower

Mostly used in Air- ConditioningMostly used in Air- Conditioning

Used at Power PlantUsed at Power Plant

Used in Super Markets /Hotels etcUsed in Super Markets /Hotels etc

Complete A/C system with Cooling TowerComplete A/C system with Cooling Tower

Types of Cooling TowersTypes of Cooling Towers Classification according to Classification according to

configurationconfiguration

Spray filled tower

Coil shed tower Dry cooling tower

3. Mechanical Components of 3. Mechanical Components of Cooling TowerCooling Tower

Ladder Drift eliminator Louvers

Hot water basin Gear box Fire protection

Mechanical Components of Mechanical Components of Cooling TowerCooling Tower

Cold water basin

Wet down system

Motor

FanPartition wind wall

Vibration switch

Mechanical Components of Mechanical Components of Cooling TowerCooling Tower

Drive shaft

Splash fills Spray nozzleWalk ways

Gate, non-return valve

4. Cooling Water Treatment and 4. Cooling Water Treatment and QualityQuality

Five types of cooling tower water problemsFive types of cooling tower water problems

Scale formationScale formation

Little dose of HCl for alkaline water, this problem is not common Little dose of HCl for alkaline water, this problem is not common in acidic water of pH(6-6.5)in acidic water of pH(6-6.5)

CorrosionCorrosion

Chromates of sodium and zinc are most commonChromates of sodium and zinc are most common

Growth of organicsGrowth of organics

Direct chlorine shock and chlorinated organic compoundsDirect chlorine shock and chlorinated organic compounds

Suspended solidsSuspended solids

Pre-treatment of water reduces this problemPre-treatment of water reduces this problem

Oil leakageOil leakage

Proper monitoring and maintenance of process equipments Proper monitoring and maintenance of process equipments

Cooling water qualityCooling water quality

Cooling Water Treatment and QualityCooling Water Treatment and Quality

Saturation index(SI)Saturation index(SI)

Saturation index = pH (actual) – pH’s (Langelier’s equation)Saturation index = pH (actual) – pH’s (Langelier’s equation)

pH’s (Langelier’s equation) = (9.3 + A + B) –(C +D)pH’s (Langelier’s equation) = (9.3 + A + B) –(C +D)

A = total solids, ppmA = total solids, ppm

B = temperature, B = temperature, 00FF

C = calcium hardness, expressed as ppm CaCOC = calcium hardness, expressed as ppm CaCO3 3

D = Alkalinity, expressed as ppm CaCOD = Alkalinity, expressed as ppm CaCO33

SI = 0, SI = 0, Water is chemically neutralWater is chemically neutral

SI > 0, SI > 0, Scale forming tendencies are presentScale forming tendencies are present

SI < 0,SI < 0, corrosive tendencies are indicatedcorrosive tendencies are indicated

Stability indexStability index

Stability index = 2 pH’s – pH (actual)Stability index = 2 pH’s – pH (actual)

Stability index = 6.5,Stability index = 6.5, scale formingscale forming

Stability index = 7.0,Stability index = 7.0, corrosivecorrosive

Stability index = 6.5-7.0, Stability index = 6.5-7.0, good rangegood range

pHpH

For good quality water ph should be within 6.5-7.0For good quality water ph should be within 6.5-7.0

Total hardnessTotal hardness

It is the sum of carbonate and non-carbonate hardnessIt is the sum of carbonate and non-carbonate hardness

· Very soft· Very soft 15 (ppm caco3)15 (ppm caco3)

· Soft· Soft 15-50 (ppm caco3)15-50 (ppm caco3)

· Medium hard· Medium hard 50-100 (ppm caco3)50-100 (ppm caco3)

· Hard· Hard 100-200 (ppm caco3)100-200 (ppm caco3)

· Very hard· Very hard >200 (ppm caco3)>200 (ppm caco3)

Concentration factorConcentration factor

The ratio of total dissolve of the cooling water to the total dissolve The ratio of total dissolve of the cooling water to the total dissolve of the of the makeup water. For good quality water it should not be of the of the makeup water. For good quality water it should not be greater then 2.0greater then 2.0

Cooling Water Treatment and Cooling Water Treatment and QualityQuality

Cooling water qualityCooling water quality

5. Cooling Towers Used in Nuclear 5. Cooling Towers Used in Nuclear IndustryIndustry

Cooling tower used at Cooling tower used at 3-miles island, USA3-miles island, USA

Natural draftNatural draft

Hyperbolic typeHyperbolic type

Cooling towers at Cooling towers at nuclear power plantnuclear power plant

Mechanical draftMechanical draft

Induced Induced

Cross flow typeCross flow type

Large fans pull air Large fans pull air across the dropping across the dropping water to remove the water to remove the heatheat

Cooling Towers Used in Nuclear Cooling Towers Used in Nuclear IndustryIndustry

Chashma NPP Cooling TowerChashma NPP Cooling Tower

CHASHMA-1Cooling Towers

Cooling tower at a Cooling tower at a European nuclear European nuclear power plantpower plant

Natural draftNatural draft

Hyperbolic typeHyperbolic type

Almost 120m highAlmost 120m high

Cooling Towers Used in Nuclear Cooling Towers Used in Nuclear IndustryIndustry

6. Comparison Between Nuclear 6. Comparison Between Nuclear and Chemical Industryand Chemical Industry

Chemicals industryChemicals industry

Average heightAverage height

= 8-15 m= 8-15 m

Blow down containsBlow down contains

Treatment chemicalsTreatment chemicals

Mostly mechanical Mostly mechanical

draft induced typedraft induced type

Selection depend on Selection depend on

the atmospheric the atmospheric

conditionsconditions

Fertilizer industryFertilizer industry Nuclear industryNuclear industry


= 22-28 m= 22-28 m



Mostly mechanical Mostly mechanical

draft induced typedraft induced type


the atmospheric the atmospheric

conditionsconditions


= 100-150 m= 100-150 m



and negligible activityand negligible activity

Mostly natural draft Mostly natural draft

hyperbolic typehyperbolic type


the atmospheric andthe atmospheric and

seismic conditionsseismic conditions

Comparison Between Nuclear and Comparison Between Nuclear and Chemical IndustryChemical Industry

Dukovany nuclear power plant(408 MWe, Check republic)

Number per unit 2

Height 125m

Top diameter 82.6m

Water evaporated 0.4m3 s

per tower

7. Conclusions7. Conclusions

The size of cooling towers at nuclear industry is almost four The size of cooling towers at nuclear industry is almost four times the size at fertilizer plantstimes the size at fertilizer plants

They are generally natural draft, hyperbolic type at nuclear They are generally natural draft, hyperbolic type at nuclear power plants because a large amount of energy is required power plants because a large amount of energy is required to run the fans, and mechanical draft, induced type at to run the fans, and mechanical draft, induced type at fertilizer plantsfertilizer plants

Blow down contains treatment chemicals in fertilizer plants Blow down contains treatment chemicals in fertilizer plants while activity also included in case of NPPwhile activity also included in case of NPP

Selection depends upon the atmospheric conditions in case Selection depends upon the atmospheric conditions in case of FPP and depends on the seismic conditions as well in of FPP and depends on the seismic conditions as well in case of NPP.Example is dry cooling tower if nuclear tower is case of NPP.Example is dry cooling tower if nuclear tower is present in desertpresent in desert

If the blow down is directly put into lake the aquatic life will If the blow down is directly put into lake the aquatic life will be in danger in case of NPPbe in danger in case of NPP

Cooling Towers and Their Cooling Towers and Their Characteristic Used in Nuclear Characteristic Used in Nuclear

IndustryIndustry

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cooling towers.ppt

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