Desalination Unit

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Desalination units


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What is desalinationWhat is desalination??

DesalinationDesalination is refers to any of several processes thatis refers to any of several processes that

remove theremove the excess saltsexcess saltsand otherand other mineralsmineralsfrom water tofrom water to

obtainobtain fresh waterfresh watersuitable for human consumption,suitable for human consumption,

irrigation, or several industrial use.irrigation, or several industrial use.

Thermal distillationThermal distillationis one of the methods used foris one of the methods used fordesalination, and that is what we use in QGdesalination, and that is what we use in QGutilities.utilities.


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GenerallyhowGenerallyhowThermal DistillationThermal Distillationgogo

on?on?

1)1) Vapor formation due to the addition of heat to salineVapor formation due to the addition of heat to saline

water (leaving behind nonvolatile impurities)! water (leaving behind nonvolatile impurities)!")") Vapor is separated from the li#uid!Vapor is separated from the li#uid!

$)$) %ondensation of the vapor due to heat%ondensation of the vapor due to heat

transfer&removal!transfer&removal!


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'efore eplaining thermal'efore eplaining thermal

distillationdistillation

we need to now the #uality ofwe need to now the #uality ofsea watersea water

we are going to treat withwe are going to treat with..


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*verage sea water *nalysis*verage sea water *nalysis

SodiumSodium 26,600 ppm Na26,600 ppm Na

MagnesiumMagnesium 6600 ppm Calcium6600 ppm Calcium

1300 ppm CaCO1300 ppm CaCO33 PotassiumPotassium 400 ppm K400 ppm K

ChlorideChloride 31,00 ppm Cl31,00 ppm Cl

SulphateSulphate 3,200 ppm SO3,200 ppm SO44 !l"alinit#!l"alinit# 1$0 ppm CaCO1$0 ppm CaCO33 %&S%&S 40,000 ppm40,000 ppm


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+ea Water salinity+ea Water salinity

(g&l)(g&l) 'alti, +ea'alti, +ea -- %aspian +ea%aspian +ea 1$ 1$ *driati, +ea*driati, +ea ".".

/a,i0, ,ean/a,i0, ,ean $$!2 $$!2 3ndian ,ean3ndian ,ean $$!4 $$!4 *tlanti, ,ean*tlanti, ,ean $2 $2 5editerranean5editerranean $6!7$6!7 8ed +ea8ed +ea 7$ 7$ *rabian Gulf*rabian Gulf 7$7$


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/hysi,al /roperties of +ea/hysi,al /roperties of +ea

WaterWater'n sea (ater)'n sea (ater)

&issol*ed salts lo(er the *apor pressure&issol*ed salts lo(er the *apor pressure

o+ pure (atero+ pure (ater Salts raise the -oiling point o+ sea (ater .sSalts raise the -oiling point o+ sea (ater .s

pure (aterpure (ater

.apor pressure lo(ering is a +unction o+.apor pressure lo(ering is a +unction o+ionic strengthionic strength Critical parameter in simulating sea (aterCritical parameter in simulating sea (ater

desalinationdesalination


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/hysi,al /roperties of +ea Water/hysi,al /roperties of +ea Water

'n sea (ater)'n sea (ater) Solu-ilit# o+ gases decreases asSolu-ilit# o+ gases decreases as

temperature and salt contenttemperature and salt contentincreaseincrease

Salt content o+ sea (ater (ill a/ect the solu-ilit#Salt content o+ sea (ater (ill a/ect the solu-ilit#

o+ car-on dioide (hich controls p ando+ car-on dioide (hich controls p andcar-onate-icar-onate euili-riumcar-onate-icar-onate euili-rium!!


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QGQGdesalination unitsdesalination units


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GeneralGeneral

7 desal units7 desal units 05401 !7C&05401 !7C& ;a,h one of 7 ,ell type;a,h one of 7 ,ell type

Gross output ! .2 tonne&hrGross output ! .2 tonne&hr


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" desal tans" desal tans05%401 !705%401 !7 ea,h tan ,apa,ity !! .>$:6 mea,h tan ,apa,ity !! .>$:6 m$$

7 desal water pumps7 desal water pumps 05P40105P401

!7C&!7C& ea,h pump ,apa,ity .2 mea,h pump ,apa,ity .2 m$$&hr&hr


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seawater supply ,ondition seawater supply ,ondition

$.@, in summer> 1.@, in winter!$.@, in summer> 1.@, in winter!min supply pressure at battery limit "!. bar gmin supply pressure at battery limit "!. bar g

desalinated water produ,ed desalinated water produ,ed 7$@, at the battery limit!7$@, at the battery limit!

$!: bar g at the battery limit!$!: bar g at the battery limit!

brine blowdown and re=e,t water is dis,hargedbrine blowdown and re=e,t water is dis,harged

at 1!. bar g to seawater ,ooling returnat 1!. bar g to seawater ,ooling return

header!header!


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%ell "%ell 1 %ell $ %ell 7

Desal pump(")

'rine pump(")

+eawater inlet

%hemi,alin=e,tion

e=e,to,ompressor

Va,uum ;=e,tor

9ogginge=e,tor

Desaltostorage

Aspe,desaltodump

Desuperheating

5/ steam

0lters

TT

BT


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/ro,ess Cow/ro,ess Cow

1) De,hlorination1) De,hlorination +eawater is being de,hlorinated before entering the+eawater is being de,hlorinated before entering the

desal units in order to oAset hypo,hlorite!desal units in order to oAset hypo,hlorite! De,hlorination agent is


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") %hemi,al in=e,tion") %hemi,al in=e,tion

'efore desalination> seawater is in=e,ted'efore desalination> seawater is in=e,ted

withwith

1!1! *ntis,ale (*ntis,ale (Belgard EVBelgard EV)> via " dosing pumps)> via " dosing pumps

rated "!7"!4 B&hrrated "!7"!4 B&hr

"!"! *ntifoam (*ntifoam (Bellite M8Bellite M8) > via 1 dosing pump) > via 1 dosing pump

rated 1!2 "!- B&hrrated 1!2 "!- B&hr


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$)$) ;vaporator system;vaporator system ;a,h desalination unit is a thermo,ompressor> multieAe,t evaporator;a,h desalination unit is a thermo,ompressor> multieAe,t evaporator

type with four evaporator eAe,ts!type with four evaporator eAe,ts!

+eawater is preheated in distillate ,ondenser! /art of it forms the feed+eawater is preheated in distillate ,ondenser! /art of it forms the feed

for the evaporators> and the remainder Cows dire,tly to the ,oolingfor the evaporators> and the remainder Cows dire,tly to the ,ooling

water return header!water return header!

*fter ,hemi,al in=e,tion and 0ltration> seawater sprayed on the heating*fter ,hemi,al in=e,tion and 0ltration> seawater sprayed on the heating

bundles of the four eAe,ts!bundles of the four eAe,ts!

For the 1For the 1ststeAe,t> seawater Cows through the tube side of e=e,toreAe,t> seawater Cows through the tube side of e=e,tor

,ondenser!,ondenser!

Desalinator heating steam is supplied from the 5/ steam header> andDesalinator heating steam is supplied from the 5/ steam header> anddesuperheated by in=e,tion of spray water supplied by desal pump!desuperheated by in=e,tion of spray water supplied by desal pump!

5/ steam enters the e=e,to,ompressor whi,h su,s and ,ompresses5/ steam enters the e=e,to,ompressor whi,h su,s and ,ompresses

the non,ondensed vapour from the distillate ,ondenser of the 7the non,ondensed vapour from the distillate ,ondenser of the 7 thth

eAe,t!eAe,t!


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The miture of 5/ steam vapor leave the e=e,to,ompressor to fedThe miture of 5/ steam vapor leave the e=e,to,ompressor to fed

into the heating tube bundle of the 1into the heating tube bundle of the 1ststeAe,t in whi,h it iseAe,t in whi,h it is

,ondensed!,ondensed!

The heat of ,ondensation is utiliHed to vaporiHe part of theThe heat of ,ondensation is utiliHed to vaporiHe part of the

seawater sprayed in the 1seawater sprayed in the 1ststeAe,t!eAe,t!

The other part of the seawater (brine) ,olle,ts at the bottom shellThe other part of the seawater (brine) ,olle,ts at the bottom shell

and Cows to the shell bottom of the net eAe,t!and Cows to the shell bottom of the net eAe,t!

The ,ondensate from the shell side of the e=e,tor ,ondenser isThe ,ondensate from the shell side of the e=e,tor ,ondenser is

routed to the tube> outlet side of the 1routed to the tube> outlet side of the 1ststevaporator> where itevaporator> where it

,ombines with the ,ondensate produ,ed by steam ,ondensing in,ombines with the ,ondensate produ,ed by steam ,ondensing in

the tubes and routed to the tube outlet of the "the tubes and routed to the tube outlet of the "ndndeAe,t evaporator!eAe,t evaporator!

3n the other side> the vapor produ,ed in the 13n the other side> the vapor produ,ed in the 1 ststevaporator Cowevaporator Cow

through the demister pad out of the evaporator! This Cow routed tothrough the demister pad out of the evaporator! This Cow routed to

the tubes of the "the tubes of the "ndndeAe,t evaporator a,ting as a heating medium!eAe,t evaporator a,ting as a heating medium!


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This pro,ess repeated in the "This pro,ess repeated in the "ndnd $ $rdrdeAe,ts!eAe,ts!

The ,ondensate from ea,h eAe,t is routed to the well of the distillateThe ,ondensate from ea,h eAe,t is routed to the well of the distillate

,ondenser!,ondenser!

The pro,ess in the 7The pro,ess in the 7ththeAe,t is diAer in thateAe,t is diAer in that

The +!W from ,ell side is pumped away to the +!W returnThe +!W from ,ell side is pumped away to the +!W return

header under ,ontrol of distillate ,ompartment levelheader under ,ontrol of distillate ,ompartment level

,ontroller!,ontroller!

Distillate from the tube side is routed to distillateDistillate from the tube side is routed to distillate

,ompartment whi,h pumped to desal tans!,ompartment whi,h pumped to desal tans!

The ,ell side vapors are routed to the e=e,to,ompressor!The ,ell side vapors are routed to the e=e,to,ompressor!

n the rundown line> there is a ,ondu,tivity analyHer whi,h willn the rundown line> there is a ,ondu,tivity analyHer whi,h will

swit,h the distillate to re=e,t (ifswit,h the distillate to re=e,t (if II1.1. JJs)!s)!


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7)7)Va,uum systemVa,uum system ;a,h Desalination Knit operates under va,uum ,onditions whi,h;a,h Desalination Knit operates under va,uum ,onditions whi,h

are established by a ,onventional powered e=e,tor system!are established by a ,onventional powered e=e,tor system! 5otive steam for the e=e,tors is supplied from the 5/ steam5otive steam for the e=e,tors is supplied from the 5/ steam

header!header!

The dissolved air in the seawater is released as non,ondensableThe dissolved air in the seawater is released as non,ondensable

vapors in ea,h evaporator!vapors in ea,h evaporator!

Finally> the non,ondensable vapors are ,olle,ted in the vaporFinally> the non,ondensable vapors are ,olle,ted in the vaporHone of the distillate ,ondenser and dis,harged to the 1Hone of the distillate ,ondenser and dis,harged to the 1ststeAe,teAe,t

through the e=e,to ,ompressor!through the e=e,to ,ompressor!

The va,uum e=e,tor pulls the non,ondensable vapors from theThe va,uum e=e,tor pulls the non,ondensable vapors from the

heating tube bundle of the 1heating tube bundle of the 1ststeAe,t through the vent ,ondensereAe,t through the vent ,ondenser

where the vapors are ,ondensed!where the vapors are ,ondensed! %ondensate from the e=e,tor ,ondenser is routed to the tube side%ondensate from the e=e,tor ,ondenser is routed to the tube side

of the 1of the 1ststeAe,t!eAe,t!

During startup> the hogging e=e,tor is used to initiate a va,uum>During startup> the hogging e=e,tor is used to initiate a va,uum>

pulling the non,ondensable vapors from the heating tube bundlepulling the non,ondensable vapors from the heating tube bundle

of the 1of the 1stst eAe,t!eAe,t!


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%ontrol of desalinated water system%ontrol of desalinated water system

Desal units operates under the following ,ontrolDesal units operates under the following ,ontrol

philosophyphilosophy

%ell


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Turn down operationTurn down operation +ometimes we need to operate desal unit on ,apa,ity+ometimes we need to operate desal unit on ,apa,ity

less than 1::L due to la, of demand of downstreamless than 1::L due to la, of demand of downstreamusers!users!

3n order to turn down3n order to turn down Determine the desired produ,tion rate!Determine the desired produ,tion rate! 5aintain the same maeup Cow (12: m$&hr)!5aintain the same maeup Cow (12: m$&hr)!

slowly redu,e the steam Cow to the e=e,to,ompressor by ad=ustingslowly redu,e the steam Cow to the e=e,to,ompressor by ad=usting69V7+:169V7+:1in in,remental steps!in in,remental steps!

This last a,tion will have a ,as,ading eAe,t> in thatThis last a,tion will have a ,as,ading eAe,t> in that

less heat inputless heat input less feed Cashing in ea,h eAe,tless feed Cashing in ea,h eAe,t less distillate produ,tless distillate produ,t88 in,rease brine blowdown +monitor the level in the brinein,rease brine blowdown +monitor the level in the brine

,ompartment!,ompartment!

3n order to in,rease produ,tion rates> reverse this3n order to in,rease produ,tion rates> reverse thisoperation! 9owever> monitor the temperature in brineoperation! 9owever> monitor the temperature in brine,ell 1 so as not to e,eed the high temperature trip of,ell 1 so as not to e,eed the high temperature trip of2.M%!2.M%!


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*,id ,leaning*,id ,leaning

When did a,id ,leaning is re#uired?When did a,id ,leaning is re#uired?When distillate output Cow from the evaporatorWhen distillate output Cow from the evaporator

units is de,reasing at an abnormally fast rate!units is de,reasing at an abnormally fast rate! *n internal inspe,tion of tubs must be made*n internal inspe,tion of tubs must be made

before ,leaning> in order to ,on0rm and re,ordbefore ,leaning> in order to ,on0rm and re,ordthe degree of s,aling!the degree of s,aling!

* $$L 9%B is used* $$L 9%B is used

* suitable %orrosion inhibitor must be used* suitable %orrosion inhibitor must be usedduring this pro,ess!during this pro,ess!

SIDEMSIDEMpro,edure is to be follow!pro,edure is to be follow!

Bicarbonate removal

H++ HCO

3

H

2O + CO

2

vente! to

atmo"#$ere


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Desal unit interlo,sDesal unit interlo,s 'rine temperature ,ell 1 high!'rine temperature ,ell 1 high!

+ea water maeup low Cow!+ea water maeup low Cow!

%ell 1 seawater maeup low Cow!%ell 1 seawater maeup low Cow!

'rine ,ell 7 very low level!'rine ,ell 7 very low level!

'rine ,ell 7 very high level!'rine ,ell 7 very high level!

Distillate ,ell 7 very low level!Distillate ,ell 7 very low level!

Distillate high ,ondu,tivity!Distillate high ,ondu,tivity!

*ir instrument very low pressure!*ir instrument very low pressure!

*ntis,ale tan low level!*ntis,ale tan low level!

*ntis,ale tan very low level!*ntis,ale tan very low level! *ntifoam tan low level!*ntifoam tan low level!

+!5!' tan low level!+!5!' tan low level!

+!5!' tan very low level!+!5!' tan very low level!


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For eN,ient operation we needFor eN,ient operation we need

to nowto now

%hermal 9:cienc#%hermal 9:cienc#


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Thermal ;N,ien,yThermal ;N,ien,y

Three prin,iples are employed to ensure thatThree prin,iples are employed to ensure thatthermal desalination is e,onomi,ally viablethermal desalination is e,onomi,ally viable

%ontrol of boiling point by ad=usting pressure to allow%ontrol of boiling point by ad=usting pressure to allow

multiple boiling at su,,essively de,reasing temperatures!multiple boiling at su,,essively de,reasing temperatures!

Kse of heat released by vapor as it ,ondenses to heat upKse of heat released by vapor as it ,ondenses to heat up

feed waterfeed water

5aintain ,lean heat e,hange surfa,es5aintain ,lean heat e,hange surfa,es

Thermal eN,ien,y is measured by the Gained utput 8atioThermal eN,ien,y is measured by the Gained utput 8atio(G8) or the /erforman,e 8atio (/8)(G8) or the /erforman,e 8atio (/8)


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;ained Output heat

losses to environment and in,rease in heat oflosses to environment and in,rease in heat of

vaporiHation as pressure de,reases!vaporiHation as pressure de,reases!

*n approimation of G8 is :!4


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;vaporator +,aling;vaporator +,aling

9/ects o+ Scaling)9/ects o+ Scaling)

3n,reased ;nergy 3nput3n,reased ;nergy 3nput

8edu,ed Distillate /rodu,tion8edu,ed Distillate /rodu,tion

3n,reased 5aintenan,e %osts3n,reased 5aintenan,e %osts


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&eposition&eposition

%riti,al parameter is 5*O%riti,al parameter is 5*Otemperaturetemperature

%al,ium %arbonate%al,ium %arbonate

" 9%" 9%$$EP %EP %$$""Q %Q %""Q 9Q 9""

%a%aQ"Q"Q %Q %$$""EP %a%EP %a%$$ 5agnesium 9ydroide5agnesium 9ydroide

99"" Q % Q %$$""EP "9EP "9Q %Q %""

5g5gQ"Q" Q "9Q "9EP 5g(9)EP 5g(9)"" %al,ium +ulphate%al,ium +ulphate

%a%aQ"Q" Q +Q +77""EP %a+EP %a+77

6$ @%

11: @%

TT

1": @%


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5y friend!!!!!5y friend!!!!!

*lways remember*lways remember


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andel chemicalscare+ull#

?ear #our PP9

Mind hotpoints

Minimi@e

en*ironmentaldamage


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'est regards'est regards

5ohammed Roraiem5ohammed Roraiem

Desalination Unit

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