chemical treatment of cooling water

8/10/2019 Chemical Treatment of Cooling Water

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Chemical Treatment of Cooling Water

In Industrial Plants

Basic Principals and Technology

By: Timothy Keister

Fellow, American Institute of ChemistsCertified Water Technologist

ProChemTech International, Inc.

Brockway, Pennsylvania

Distribution: eneral

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'ue to the worldwide com$etitive nature of industrial activity today, all industrialmanufacturers must maintain strict control over various sources of $roduction cost&Cooling water is a commonly neglected area of the $roduction $rocess which is often

res$onsi(le for su(stantial cost increases due to downtime, e)ui$ment damage, loss of$rocess control, and increased energy usage& *ther items which relate to treatment andcontrol of cooling water+ such as water and sewerage costs, environmental regulations,and lack of sufficient fresh makeu$ water can also have su(stantial im$acts on allas$ects of manufacturing o$erations& -eglect of cooling water results from two items+first, the manufacturer often does not a$$reciate that cooling water is a vital $art of the$roduction $rocess and second, the fact that misinformation, .snake oil. $roducts, andmarketing .hy$e. are common when cooling water treatment is the issue underdiscussion&

This $a$er is intended to $rovide the industrial manufacturer with a (asic knowledge of

$ro$er cooling water treatment so that $ro(lems resulting from corrosion, scale,de$osition, and (iological fouling can (e avoided& /eduction of o$erating costs fromincreased efficiency in use of energy and control of (oth makeu$ water and sewerage usewill (e discussed, as well as avoidance of environmental $ro(lems and su$$lier selection&

Any discussion of cooling water treatment must (egin with an o(0ective statement ofwhat is e$ected from the cooling water system& In manufacturing $lants, the coolingwater system must $rovide relia(le $roduction e)ui$ment cooling with maimum heattransfer efficiency& The following four (asic re)uirements are derived from thiso(0ective&

%& 'inimi(e problems from corrosion, scale, deposition, and gro)th to

obtain ma*imum efficiency.

+& Implementation and control must be do-able )ith a minimum input

of labor and money.

& Cost effecti/e as possible considering the total )ater system capital

and operating costs.

0& 'ust be en/ironmentally acceptable.

These four re)uirements form the (asis for the following discussion of cooling watercontrol and treatment&


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*ne of the most interesting o(servations we have made over the years is that o$erationalcontrol of cooling water treatment $rograms is invaria(ly neglected and is thus the singlemost common cause of $rogram failure& The (est $ossi(le com(ination of corrosion,

scale, and de$osition control chemicals, with effective (iocides, is com$letely worthlessif not consistently and correctly a$$lied to the cooling water&

CyclesCooling water chemistry control (egins with cooling water cycles of concentration 7C&,or the num(er of times that the dissolved salts in the fresh ma8eup )ater 7'$&areconcentrated (y eva$oration from the cooling system& This $arameter is commonlyo(tained (y measuring the conductivity of the cooling )ater 7CW&and dividing it (y themeasured conductivity of the makeu$ water& Please note that cycles can also (e calculatedusing other $arameters, such as chlorides and dissolved solids, which are common to (oththe makeu$ and cooling water and are not e$ected to (e effected in any great degree (y

chemical additions or$reci$itations&

C 2 CW conductivity"34 conductivity

Control of cycles is critical in systems using non5softened makeu$ water as no chemicaltreatment $rogram can co$e with the increased $otential for scale formation resultantfrom ecessive levels of hardness salts in cooling water caused (y very high cycleso$eration&

Why Cycle*ne )uestion that occasionally surfaces is .why use chemical treatments to o$erate atadditional cycles when often no scale will form when o$erating at lower cycles.& The(est answer is that o$eration at increased cycles substantially lo)ers both the ma8eupand blo)do)n re9uirements, cutting the cost of fresh water and sewage dis$osal& Withcorrosive waters, increasing the cycles so that the water is rendered less corrosive is a.chea$. means to im$rove control of corrosion& Another $oint is that o$eration atincreased cycles $ermits use of effective corrosion inhi(itors that may (e too costly toem$loy at the higher (lowdown rates resultant from low cycle o$eration& Ty$ically, themost economical cycles to o$erate at is in the range of # to 6&


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8nvironmental re)uirements and lack of sufficient fresh makeu$ water are newer forcesdriving cooling tower o$eration to higher cycles& We have recently seen cases wheresewer ta$ fees for new $lants, measured in 91, amounts, were reduced to 91,sim$ly (y increasing cycles from # to 6& The environmental agencies are also taking amuch closer look at $lant water use, one recent -P'8: $ermit issued in Pennsylvania

contained a condition that the $ermittee reduce its water discharge (y ;


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Cycles 5 ControlTwo methods have (een found to yield the (est control of cycles&

The first, which is re)uired when makeu$ water chemistry varies su(stantially or the$lant has uncontrolled water losses, is to use an automatic control system (ased on

measuring the conductivity >$ro$ortional to the level of dissolved salts in the water? ofthe cooling water& When the conductivity reaches the determined control level, anautomatic valve is activated and high dissolved salt content water is drained from thecooling water system& /e$lacement of this drained water or blo)do)n 7BD&with freshwater lowers the conductivity of the cooling water, which causes the automatic valve to(e deactivated&

Another means to control cycles automatically utili@es the makeu$ $ro$ortional method,where the amount of makeu$ water added to the cooling system is measured and a$ro$ortional amount of (lowdown drained from the system via o$eration of an automaticvalve controlled (y a makeu$ water meter activated timer& Thus to o$erate at ten cycles,

for every 1 gallons of makeu$ water added to the cooling water system,a$$roimately 1 gallons of (lowdown would have to (e drained& The e)uation for thisis+

B' 2 34"C

While this method is only a$$lica(le when the makeu$ water is of fairly consistent)uality and the $lant is low leakage, it is less costly to install and maintain than aconductivity (ased system and yields the same degree of control& An additionaladvantage is that there is no conductivity electrode which re)uires routine maintenance&

As maintaining a set cycles value is the (asic control function in cooling water treatment,only high )uality, easy to maintain e)ui$ment should (e used so as to o(tain the mostaccurate, consistent, and relia(le control $ossi(le&

Chemical Feed Control3any methods have (een used over the years to control the addition of chemical inhi(itor$roducts to cooling systems& Common $ractices have included manual (atch feed timercontrolled feed constant feed .feed"(leed., where chemical is in0ected simultaneouslywith (lowdown $ro$ortional feed and active control feed, where a relevant $arameter ismeasured and inhi(itor feed used to maintain a set $oint&


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Critical evaluation of these various methods over the years has shown that the (estchemical inhi(itor control method is that using $ro$ortional feed& This is (ased u$on thefact that all chemical $roducts, with the ece$tion of (iocides, are dosed according to theamount of (lowdown from the cooling system, which is directly $ro$ortional to theamount of makeu$ added&

Pro$ortional chemical feed systems are )uite sim$le, (eing (ased u$on metering theamount of makeu$ water added to the cooling water system and activating a chemicalmetering $um$ via a timer to add an amount of inhi(itor $ro$ortional to the amount ofmakeu$ added& As with control of cycles, only high )uality e)ui$ment which $rovidesthe (asic control function should (e used&

The various .com$uteri@ed. and .on5line. control systems now (eing marketed have notechnical advantage over the (asic control methods 0ust discussed& In fact, due to theincreased com$leity of such systems, they are often less relia(le than (asic controls andare al)ays more e*pensi/e to purchase and maintain&

While active control feed systems should have a technical advantage over $ro$ortionalcontrol systems, i&e& they are .measuring. the control $arameter in real time andmaintaining control, in $ractice the systems on the market utili@e an easy to measuretracer compoundadded to the inhi(itor& :everal cases have (een documented where thetracer level has (een within control limits, (ut the actives in the inhi(itor were not due toselective $reci$itation and"or a(sor$tion within the cooling system& *ur commentsconcerning high costand poor reliabilitya$$ly even more to this ty$e of control systemat the $resent time&

Calculation of ParametersCalculation of the various o$erating $arameters for a cooling system is very im$ortant asto initial si@ing and su(se)uent monitoring of control system $erformance& We havefound the following e)uations to (e the most accurate for o(taining values for systeme/aporation 72&, blo/do)n 7BD&, )indage 7W&, and ma8eup 7'$&as gal"day&2/aporationis easily calculated (y+

8 2 heat load (tu"hr >E? !7 hr"day &


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acid? or mechanical cleaning&

:cale formation on the condensers of freon cycle chillers reduces the efficiency of theseunits for removal of heat from chilled water systems, thus increasing the $ower needed too(tain a given volume of chilled water& arious studies have shown a non5linearelectrical $ower cost increase with increased scale thickness, for instance &D mils ofcalcium scale results in a $ower cost increase of #&D=, while 1&D mils increases $owercost to a$$roimately 1!&D=&

Control:cale can (e controlled, or eliminated, (y a$$lication of one, or more, $roven techni)ues&Ty$ical measures taken to control scale start (y controlling cycles followed withchemical scale inhi(itor treatment, $ ad0ustment (y acid addition, or softening ofcooling water system makeu$&


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As noted, cycles are (est controlled (y installation of a high )uality system for automatic(lowdown (ased on conductivity or metered makeu$& Chemical scale inhi(itors function(y either selective adsor$tion on growing scale crystals, converting the crystal structureinto a non5scaling ty$e which does not form a hard scale, or chemical reaction with thescale forming ions, converting them into non5scale forming materials&

The following list notes some of the chemical scale inhi(itors commonly encountered&

Chemical Comments

Polyacrylate Commonly used, cost effective for calcium scale at D to 1Dmg"l&

>mw 2 !?Polymetbacrylate Gess common for calcium scale at D to 1D mg"l&Polymaleic ery effective for calcium scales at 1 to !D mg"l, costly&4ulfonated 8ffective calcium inhi(itor, lesspolystyrene sensitive to iron levels, commonly used at levels of 1 to !

mg"l&Phosphonates All three common $hos$honates are ecellent calcium scaleinhi(itors at levels from D to ! mg"l&

Chelants Both 8'TA and -TA, as well as citric acid and gluconate,have seen some limited use for calcium scale control atlevels from D to 1 mg"l&

Dipolymers These $roducts commonly incor$orate two active grou$s,such as sufonate and car(oylate, to $rovide su$erior$erformance to a single grou$ com$ound& 4se levels at Dto ! mg"l&

Terpolymers Gike the di$olymers, only incor$orate three active grou$sto give yet (etter $erformance under severe conditions&4se levels at D to ! mg"l, costly&

Polyphosphates Fairly good calcium scale control under mild conditions,can revert and contri(ute to calcium $hos$hate scale&

As with corrosion inhi(itors, mitures of scale control chemicals have (een found togenerally $rovide su$erior $erformance to single com$onent $roducts& Thus mostformulated $roducts will often contain two, or more, materials, ty$ical formulationsusually contain one, or more, $hos$honates com(ined with $olyacrylate&


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As a general rule, ty$ical chemical scale inhi(itors can (e utili@ed if the 6angelier4aturation Inde* 74I&value of the cycled cooling water does not e*ceed +.;& Cycledcooling water :I values eceeding !& normally re)uire use of eotic chemistries, $ad0ustment (y acid addition, or makeu$ water softening& *ur firm, as well as some others,has re$orted o$eration of cooling systems, with newer treatment chemistries, scale free at

cycled :I values from !&; to #&D without $ ad0ustment&

$ Ad0ustmentControl of scale with $ ad0ustment (y acid addition functions via chemical conversionof the scale forming materials to more solu(le forms& Thus, calcium car(onate isconverted to calcium sulfate >using sulfuric acid for $ ad0ustment?, a material severaltimes more solu(le& -ormally, it is not desira(le to add sufficient acid to convert all ofthe scale forming materials due to a su(stantial increase in the corrosivity of the coolingwater if this is accom$lished&

*f course, addition of ecessive acid to the cooling water results in de$ressed $ values

and etremely ra$id corrosion of all system metals&

The :I and another inde, the /y@nar :aturation Inde >/:I?, are utili@ed for systemsetu$ when $ ad0ustment (y acid addition is used for scale control& Both indees aremerely convenient means of reducing the integrated $arameters of calcium, alkalinity,$, dissolved solids, and tem$erature to a single value, which indicates the tendency ofwater to form a calcium scale or $romote corrosion& Thus,, a $ositive :I num(er >/:Iless than D&? indicates a scale forming water, while a negative :I num(er >/:I greaterthan /:I (etween D&and 6&? when utili@ing $ ad0ustment (y acid addition and add some chemical scaleinhi(itor to co$e with the resultant slight tendency to scale& Instances have (een re$ortedwhere scale has (een controlled with makeu$ calcium water hardness values u$ to #mg"l as CaC*# with a com(ination of $ ad0ustment (y acid addition and chemical scaleinhi(itors&


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:I Calculation4sing a standard water analysis, the :I can (e easily calculated using the followinge)uations with a hand calculator& Gogs are (ase 1, analysis results in mg"l&

1& PI 2 Gog >calcium !&D total alkalinity?

!& 'etermine the highest e$ected water tem$erature >F? in the cooling system and use itas follows+

P! 2 >>F? &H1!? PI

#& P# 2 >>Gog >T':?? &1? 1!&!:I? 2 $ water 5 $ saturation

-otes+ Conductivity &; can su(stitute for T':

An im$ortant $oint to remem(er is that acid addition to cooling water should only (eundertaken with an automatic p3 controlsystem and )ell trained operators& Thiscaution is included as serious corrosion damage will occur in a short $eriod of time ifecessive acid is added to the cooling water& *nly high )uality $ controllers e)ui$$edwith acid $um$ lockout timers should (e considered for this critical a$$lication& 'aily$lant control testing is re)uired with use of $ control systems&

While not yet common usage, scale can (e com$letely eliminated (y softening all coolingsystem makeu$ water& It has (een our e$erience that using softened makeu$ water forscale control is the safest, most cost effective method availa(le& -ormally, the added costof softened makeu$ water is (alanced (y the decreased chemical and water usageresultant from the increased cooling system cycles made $ossi(le (y the soft water&

The increased general corrosiveness of the softened water is countered (y the high $values >;&D to H&D? develo$ed when the cooling system is cycled u$ with softenedmakeu$& This, in com(ination with a good chemical corrosion inhi(itor $rogram, usuallyresults in lower corrosion rates than the same cooling system using chemical scaleinhi(itors or $ control (y acid addition& !ote thats$ecific inhi(itor technology forcontrol of )hite rustmust (e utili@ed with softened makeu$ water&


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16? cycles, some formof (y$ass filtration is re)uired to $revent de$osition and resultant under de$osit corrosion$ro(lems& In dusty environments, such of (y$ass filtration may (e re)uired, regardless ofthe chemistry or cycles o$erated at&


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3icro(iological growth within a cooling water system, if not controlled, can result information of (iological fouling layers on all surfaces in contact with the cooling water&The (iological fouling effects $rocess o$eration much like the $reviously discussed scale

and de$osition, the (iological fouling acting as a thermal insulator to decrease heattransfer efficiency in the $roduction e)ui$ment& Biological fouling usually results insu(stantial corrosion rate increases due to formation of anaero(ic areas under the foulinglayer, which creates galvanic cou$le corrosion, and formation of meta(olic (y$roducts,such as hydrogen sulfide, which actually attack the (ase metals&

:evere cases of (iological fouling have resulted in com$lete cooling system failure due tothe (iomass $hysically $lugging cooling water $assages in $roduction e)ui$ment andcooling towers&

Water(orne diseases, such as 6egionnaire?s Disease, are also a ma0or health and safety

concern with o$eration of many cooling water systems& :ystems which are notmaintained in a clean and (iologically controlled state can often (e sources of suchinfections, which can sicken, or even kill, e$osed em$loyees&

ChemistryPresent $ractice for control of (iological fouling is to $eriodically dose the coolingsystem with a (iocide to kill as many of the organisms $resent as $ossi(le& Again, thecritical $oint concerning control of (iological fouling is to remem(er that the dose ma8esthe poison& sim$ly $ut, a (iocide will not work unless a critical dosage is reached andmaintained for a set time $eriod& The critical dosage $oint and time re)uired for effectivemicro(iological control varies su(stantially with the s$ecific (iocide in use and theoverall condition of the cooling water system&

The (iocides commonly used can (e (roadly (roken into two ma0or classes, oidi@ingand non5oidi@ing

*idi@ing (iocides function (y chemical oidation of the cellular structure of theorganism, which effectively destroys it and kills the organism& 'ue to the destructiveform of attack, it is impossible for any organism to sho), or de/elop, significantimmunity to an o*idi(ing biocide& *idi@ing (iocides are usually )uite cost effectivedue to their low unit cost, ra$id effect on the target organism, and low effective dosage&


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4nfortunately, oidi@ing (iocides do have some draw(acks&

5 :ome can decrease coolingMwater $ in a uncontrolled manner >gas chlorine andchlorine dioide generators?&

5 3ost increase the corrosive nature of the cooling water&

5 :ome, such as chlorine, $roduce undesira(le (y $roducts from an environmentalstand$oint&5 Corrosion and scale control chemicals can (e inactivated (y contact with s$ecific

oidi@ers&5 -one of the oidi@ing (iocides have any dis$ersant effect for removal of dead

micro(iological growth and"or $enetration of organic slime layers&5 Process contamination can neutrali@e many oidi@ers&5 :ome oidi@ers are sensitive to water $ as to effectiveness&

The following list notes some common oidi@ing (iocides and our comments+

Chemical CommentsBromochlorodimethylhydrantoin ery effective $roduct at 1! to #6 mg"l $roduct,costly for an oidi@er on a $er $ound (asis, safe touse

Chlorinedio*ide 8tremely effective $roduct at &D to ! mg"l active,must (e generated on5site from reactive ingredients,lowers system $, contact measured in minutes,few environmental $ro(lems, some safety $ro(lems

Chlorine The .old. stand(y and still most cost effective$roduct availa(le at levels of &D to 1& mg"l&Pro(lems include :A/A Title III status, danger ofworking with $ressuri@ed gas, and lowering ofsystem $& :ome environmental $ro(lems withchlorinated hydrocar(ons noted&

#(one ery effective (iocide, ma0or $ro(lem is cost andmaintenance of on5site generator and $ure airneeded& *@one emissions from cooling tower maycreate a first class environmental $ro(lem&

6i9uid and solid chlorines 4sually cost effective, (ut increase system $values, white rust and >hy$ochlorites? corrosion&:ome solid $roducts add calcium to system&

3ypochlorite@3ypobromite /ecently introduced technology that generatesactive oidi@ers on5site using electrolysis of neutralsalts& 3ay (e the (est choice from the stand$ointsof safety and effectiveness&


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The recent introduction of on5site generator"feed systems for chlorine dioide,hy$ochlorite, and hy$o(romite eliminates some of the $ro(lems with oidi@ing (iocidesand have (een demonstrated to (e an effective and safe means to attain good (iologicalfouling control& 4nfortunately, the ca$ital cost of these installations can only (e 0ustifiedfor larger or $ro(lem cooling systems&

-on5oidi@ing (iocides function (y interference with the meta(olism of the organism in avariety of ways, which (y $reventing normal $rocesses, kills the organism& 'ue to thelarge variety of organisms, those that are immune to a $articular non5 oidi@ing (iocidewill ra$idly re$lace those that are killed (y a single dosage& Following doses will (ecome$rogressively less effective as the organism $o$ulation shifts to those varieties that areimmune to the $articular (iocide em$loyed&

'ue to this natural effect, it is recommended that at least two different non5oidi@ing(iocides, or a oidi@ing and a non5oidi@ing (iocide, (e utili@ed in (iological control$rograms on an alternating (asis&

-on5oidi@ing (iocides can (e )uite costly due to the high effective dosage re)uired withsome $roducts, long contact times re)uired with some $roducts, and their often high unitcost&

-on5oidi@ing (iocides do have advantages in that most function in the $resence of$rocess contamination, no effect on corrosivity is evident from their use, corrosion andscale control chemicals are usually not effected (y them, often they can (e targeted at as$ecific class of $ro(lem organism, and several have a definite dis$ersant effect forremoval of dead micro(iological growth&

The following list notes some of the non5oidi@ing (iocides, and our comments,commonly encountered&

Chemical Comments3ydro*ymethyl nitro propanediol 8ffective only with a long residence time dosage of


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We have calculated the following generic $roduct use cost, calculated as 9 to treat 1gallons of cooling water, (ased on using the recommended dosages and list $rices for thevarious (iocides su$$lied (y our com$any&

Product Cost Product Cost

!= $oly)uat 9&


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If it is not $ossi(le to determine the actual system volume, we have found that thefollowing .rules of thum(. give good starting $oint volumes&

:tandard cooling tower systems 1D gallons"ton

8va$orative condenser systems ! gallons"ton

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While the chemistries of makeu$ waters are almost unlimited, a few generali@ations can(e made concerning classes of makeu$ water and the s$ecific treatment chemistrieswhich have (een found to (e most effective&

A& -atural low alkalinity, low hardness waters with :I less than 51& are found in someareas of the country and, like softened waters, are normally very corrosive& 3any of thetreated industrial wastewaters (eing considered for reuse as cooling tower makeu$ fitwithin this classification& These waters were formerly treated successfully using

$rograms (ased on the now environmentally outlawed high chromate5@inc chemistry&They are now (est treated (y using a (lended $roduct containing at least two goodinorganic corrosion inhi(itors, such as silicate, @inc, or moly(date an organic inhi(itorsuch as $olydiol and an a@ole for yellow metal $rotection& A dis$ersant to controlde$osition and some $hos$honate to control de$osition of $roducts of corrosion willcom$lete the $rogram& In most cases, all of the a(ove chemistry can (e (lended into asingle $roduct&

B& 3akeu$ waters with alkalinity and calcium hardness values (etween D and ! mg"l,:I 51& to 1&, are commonly found throughout the country& These waters $ermit a muchwider selection of water treatment chemistries, which are all ca$a(le of giving acce$ta(le$erformance with $ro$er selection and control& The following chemistries are generallya$$lica(le to these waters+

1& The classic water treatment chemistry for this ty$e of water was to control scaleformation (y $ ad0ustment, using a high chromate5@inc, sometimes with $hos$hate,chemistry to very effectively control corrosion& 'is$ersants were added to the laterformulations to control de$osition& While $rograms (ased on this chemistry are veryeffective and economical, they have (een (asically outlawed (y environmentalregulations&


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!& Programs which use only $hos$honate and $olymer chemistry to control scaleformation, commonly referred to as .all organic. have (een introduced and used withgood results& :cale is handled as noted, while corrosion is controlled (y formation of alayer of a(sor(ed calcium"iron $hos$honate on the metal surfaces, and develo$edhardness and alkalinity& The (etter $rograms also include a@ole for yellow metal

$rotection and may have additional dis$ersants for (etter de$osition control& 3oly(dateat levels of 7 to 6 mg"l is often added as an easy to test for tracer and additional $ittingcorrosion control&

#& Phos$hate inhi(itor chemistry using $ ad0ustment to maintai the cooling water in anon5$hos$hate scale forming region >usually s? are inuse& 3oly(date has (een added to some $rograms as (asically a tracer for control testingand for added control of $itting corrosion&

D& *ur firm has develo$ed an additional chemistry, T/APtm, (ased on$hos$hinocar(oylate, $olydiol, and advanced $olymer chemistry, which allows muchhigher cycles to (e o(tained with such makeu$ waters& :cale is controlled (y these)uestrant 5 dis$ersant action of the chemistry, while corrosion is controlled (y the veryhigh develo$ed alkalinity and formation of organic $olydiol films on metal surfaces&:everal s$ecific $roducts have moly(date incor$orated in the formula for control testingand additional $itting corrosion control& This ty$e of $rogram is not yet in common usedue to its high chemical cost a$$lications to date have (een restricted to water shortareas, very hard waters, or @ero discharge systems&


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In all of the a(ove $rograms, @inc can (e added as a su$$lemental corrosion inhi(itor, (utuse of this metal is under increasing environmental $ressure& At least two organiccorrosion inhi(itors, $olydiol and hydroy $hos$honocar(oylate, are also (eing used to$rovide additional corrosion $rotection&

C& 3akeu$ waters with calcium hardness and alkalinities over # mg"l and giving :Ivalues eceeding !&D, at only ! to # cycles, are less common, (ut are coming intoincreased use in some $arts of the country due to water shortages& Three $rovenchemistries are availa(le to treat this ty$e of makeu$ water+ $ ad0ustment with use ofeither organic or $hos$hate inhi(itors, softened makeu$ with use of good inhi(itors, orT/APtm chemistry& Control of scale with cycled :I values eceeding #& and calciumhardness values eceeding ! mg"l has (een demonstrated with T/APtm chemistries&

The use of softened makeu$ water has $roven to (e very successful with these hardwaters& Corrosion is routinely controlled to levels of I mil"yr or less on mild steel, while$rogram cost is e)ual to, or less, than other $rograms, with no scale formation& :oftened

makeu$ is also re)uired for o(taining @ero discharge with most waters& The high cyclesre)uired for (alancing (lowdown against windage cannot (e o(tained without scaleformation unless the makeu$ water is softened&

=III. 4$PP6I2" 4262CTI#!

While the foregoing $rovides the industrial manufacturer with the (asics for $ro$ercooling water treatment, the actual chemistry of the $rogram is in the hands of thesu$$lier selected (y the facility& It is thus im$ortant that a knowledgea(le su$$lier (eselected who can $rovide a$$ro$riate control systems and chemistry tailored to the $lantcooling systems and makeu$ water )uality&

The following are some comments on the selection of a water management $rogramsu$$lier&

BusinessThe su$$lier selected should (e in the industrialwater treatment (usiness and deal on aroutine, direct (asis with various industrial manufacturing $lants& There are many firmsin the market, in $articular $roduct distri(utors and AC contractors, that deal in suchthings as floor cleaners, solvents, oils, AC e)ui$ment"maintenance, or water softenerswho would also (e ha$$y to sell a few drums of cooling water treatment OBrand toanyone&


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!CWT? $rogram, $ut in $lace a(outfour years ago and o$en to anyone in the water treatment industry, is the one means ofesta(lishing the needed e$ertise in this field&

8nvironmental8$ertise in environmental regulations and water conservation is also (ecoming a ma0orconsideration in selection of a water management $rogram su$$lier& The su$$lier shouldhave the ca$a(ility to consider the effect of environmental regulations on the s$ecificchemistry to (e used, and $rovide any information needed (y the regulatory authorities&

While the returna(le (ulk containers (eing .$ushed. (y several of the large firms in thewater treatment industry for avoiding container dis$osal $ro(lems sound good, they do$resent some $ro(lems of their own& The increased cost of the (ulk container, ascom$ared to the standard drum, usually results in a higher cost for $roducts delivered inthis mode as com$ared to drum $rices&

A ma0or environmental consideration is the $otential for environmentally damagings$ills& Goss of ! to #D gallons from a (ulk container is several times more damagingthan a loss of DD gallons from a drum& As an eam$le, note that :A/A re$orting limits,(eing (ased on the amount of material s$illed, may often (e triggered (y a (ulk s$ill, andnot (y a drum s$ill&


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We would recommend that the container dis$osal issue (e sim$ly and economicallyaddressed (y using a su$$lier that will sim$ly acce$t return of all em$ty $roductcontainers, from five gallon $ails right through (ulk containers& This $ermits the mosteconomical $ackaging to (e selected from (oth the usage and cost stand$oints, avoiding alot of the .marketing hy$e. for which the water treatment industry is known& /eturn of

all em$ty containers totally eliminates any container dis$osal $ro(lem and im$roves theenvironment (y recycle of the $ackaging&

From a stand$oint of water conservation, the su$$lier should have s$ecific in de$thknowledge of (lowdown reduction and @ero discharge technologies& As noted, this is as$eciali@ed area and few su$$liers have yet develo$ed the e$ertise, e)ui$ment, andchemistries needed to $rovide cost effective $rograms& The (est means of o(taining afirm with e$ertise in this field is to note any technical $resentations made (y the firmand references as to com$leted $ro0ects& 8$erience is the (est means to ensure )ualitywork in this new, and ra$idly evolving $art of the water treatment field&

Gocal :erviceThe local service re$resentative of the su$$lier is also very im$ortant to the success, orfailure, of any water treatment $rogram due to intimate involvement in chemistrys$ecification, $rogram control, and trou(leshooting& The user is advised to carefullyscreen the su$$lier re$resentatives and o(tain one who has (oth a technical (ackgroundand e$erience in the cooling water treatment field as a$$lied to industrial $lants&

IA. 4!1K2 #I6

In many ways the industrial water treatment resem(les the used car market& While thereare many re$uta(le com$anies that maintain high $rofessional standards and will do anecellent 0o( in most cases, there are also many .snake oil. firms that sell technologiesthat are (asically worthless or not a$$ro$riate& 8am$les of such items are the many.magnetic., .electronic., and .catalytic. water treatment devices that have (een sold forthe $ast sity years& *(0ective testing has never found a single such device to $erform asadvertised&

An ecellent eam$le of a technology that has (een sold for ina$$ro$riate uses is o@one&:everal firms have claimed that o@one can (e used to control corrosion, scale, andde$osition as well as its esta(lished use as an ecellent oidi@ing (iocide& Again,o(0ective testing has $roven that o@one is (asically ineffective as a corrosion, scale, andde$osition control agent&


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Poor cooling water treatment and control increases $roduction costs in industrialmanufacturing $lants& :election of a cooling water treatment $rogram and su$$lier (asedon some knowledge of the chemistry and control needed will increase the $ro(a(ility of

o(taining relia(le $roduction e)ui$ment cooling with maimum heat transfer efficiencyat the lowest total cost& Those facilities who devote sufficient time and resources to thisvital area of their $rocess will (e rewarded (y lowered $roduction costs and a com$etitiveedge&

Qnowledge of the field will also ena(le the (uyer to se$arate .snake oil. $roducts fromvalid technologies and guard against the $ro(lems that can result from use of suchsomething for nothing $roducts&

Timothy Qeister 5 olds a B&:c& in Ceramic :cience, Fellow of the American Institute ofChemists, and is a Certified Water Technologist& e has (een the Chief Chemist ofProChemTech since founding the firm in 1H;

chemical treatment of cooling water

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