Boiler Overview

•  Steamisthebasicenergytransfermedium  Usesinclude

  Residen7alandcommercialhea7ng  Plantprocesssteam  Plantpowergenera7on  U7lityplantopera7on

•  Cri7caltotheopera7onoftheboileriswaterpurity•  Thecomponentssurroundingatypicalboilersystem

includethefollowing:

  Pretreatment(ionexchange,filtra7on)  Dearator(combinedwithcondensatereturn)  Economizer(heatreuse)  Steammanagementequipment(headers,traps)

Pretreatment

•  Preparethewatertobeboiled  Calciumandmagnesiumsaltsaremost

insolubleinthehoHestareas

•  Goalofpretreatment  Minimizewateruseorwastage  Minimizechemicaluseandreduceoverallcosts

•  Commonmethods  SoLening‐exchangehardnessforlessharmfulion  LimesoLening‐precipitatehardness  Filtra7on‐removesolids  Demineraliza7on‐exchangeallionsforH+&OH‐

  Reverseosmosis‐removeallionstoconcentrate

Softening

•  Removeshardnessinexchangeforsodium

•  RegeneratesoLenerwithsodiumchloride

•  Hardnessproblemsandconsequences  Ironfouling,organicfouling,poorregenera7on,poorcontrol,

damagedinternals  Increaseddeposi7oninboiler,lossofheattransfer

ZeoliteSoLener

Na*Resin

Ca/Mg*Resin

[Ca&Mg]*[SO42Cl2HCO3]

[Na2SO42NaCl2HCO3]

Deaeration

BasedonDalton’sandHenry’sLawsofgassolubilityinwaterrela7ngtopressureandtemperature.

Deaeration

•  Toomuchoxygenintheboilercausesrust4Fe3O4(magne7te)+O26Fe2O3(hema7te)

•  Canremovethisoxygenmechanicallyorchemically  Mechanically

  Increasetemperaturedrivingoffoxygen  Increasesurfaceareaofwaterdrivingoffoxygen

  Chemically  Sulfitereactswithoxygentomakesulfateinwater  Organicacid,hydrazine,DEHA,hydroquinone

•  Combina7onofmechanicalandchemicalmeansistypical

Boiler System

•  Firetubeboilers  Combus7ontakesplaceinsidetubes  Wateronshellside,mustkeepimpuri7esfrom

s7ckingtotheoutsideofthecombus7ontubes  MudgravityseHlestoboHomtobeblowndown,withsteam

outthetopofthevessel  Commonpackagedsystems

•  Watertubeboilers  Waterontubeside,tubesconsistofrisersanddowncomers.

Steamisontopinthesteamdrum,withdepositscollectedinboHommuddrum

  Severalshapesandsizesexist  Inspec7on

Water Treatment Programs •  Inaboiler,mineralcontentinthe

remainingboilerwaterisconcentrated;ionsdonotevaporate

•  Cyclesofconcentra7on

•  Internalboilerwatertreatmentprograms  Precipita7ngprograms

−  Phosphatebasedprograms  (10Ca2+6PO4

2‐+2OH‐Ca10(OH)2(PO4)6)  Analy7caltes7ngproceduresandreview

  Solubilizingprograms−  Allpolymerdispersantprograms

  Analy7caltes7ngproceduresandreview−  Chelantprograms

  Analy7caltes7ngproceduresandreview

Condense Treatment

•  Oncesteamisused,itiscondensedandreturnedtothefeedwatersystem  ThemorereturnedthebeHer

  Savingsinmakeupwater,becausefeedwateriscomposedofmakeupandcondensatereturn

  Savingsinheat,withcondensateabout140degreeshoHerthanmakeup,sofor1lbofwater,ittakes140BTUofenergytogetmakeuptoanequivalenttemperature

•  Thecarbondioxideinsteamcondensesandcanformcarbonicacid,unlesspHiscontrolled

•  Neutralizingamines  Theycondenseinselec7veloca7ons

inthecondensatesystem(near,intermediate,andfar)

Testing Methods

•  Analysisofimpuri7espresentinwater

•  Repor7ngquan77es  Explana7onofpartspermillion

•  Titra7ons  Alkalinity,sulfite,hardnessandchlorides

•  ColorimetricTests  Phosphate,molybdates

•  On‐lineinstrumentaltests  TDS/conduc7vitymeasurement/pH

  Forsurfaceblowdownandcondensate

Test Procedures

•  HardnessTest–SoLener&Condensate1.  Measure100mLofsample2.  Add2brassdipperfulofHardnessBufferReagent(Code291)

ands7r3.  Add1brassdipperfulofHardnessIndicatorReagent

(Code290)ands7r.Ifsampleisblue,thewaterissoL4.  AddHardnessTitra7ngSolu7ondropbydropun7lcolor

turnsblue5.  Mul7plybureHereadingby10todeterminepartspermillion

totalhardness6.  Controlatlessthan1.0ppm

Test Procedures

•  SulfiteTest–BoilerWater1.  Measure50mLofsample2.  Add4dropsofPhenolphthaleinIndicator(Code212)3.  Add1plas7cdipperfulofSulfiteIndicator(Code219)ata

7meands7rbetweeneachaddi7on.Con7nueaddi7onun7lredcolordisappears,thenaddoneaddi7onaldipperful

4.  SlowlyaddPotassiumIodide‐Iodatesolu7on(Code237).S7rconstantlyun7lafaintpermanentbluecolordevelops

5.  Mul7plybureHereadingby10todeterminepartspermillionsulfite.

6.  Controlat30–60ppmsulfite

Test Procedures

•  NeutralizedConduc7vity–BoilerWater1.  To50mLboilerwater,add1mLofLiquidConduc7vity

Reagent(Code944)ata7meandswirltomixun7lcolorless2.  Measureconduc7vityonMyronconduc7vitymeter3.  Controlat4000–5000umhos

Test Procedures

•  Orthophosphate–BoilerWater1.  Add5mLoffilteredsampletomixingtube(Code152)2.  AddMolybdateReagent(Code236)tosecondmark(15mL)3.  Stopperandmix.AddonebrassdipperfulofStannous

Reagent(Code239),stopperandmixwell4.  Placemixingtubeinviewingcompartment,compare,

andrecordresult5.  Controlat30–60ppmphosphate

Test Procedures

•  HydroxylAlkalinity–BoilerWater1.  Fillmixingcylinderto25mLmarkwithboilerwater2.  Add1mLbariumchloridesolu7on,swirltomix3.  Add2dropsPhenolphthaleinindicator,swirltomix4.  Addsulfuricacidreagentonedropata7me,un7lcolor

changesfrompinktoclear5.  Mul7plynumberofdrops7mes506.  Controlat200–400ppm(4–8drops)hydroxylalkalinity

•  pH–Condensate1.  UsepHmeter,controlatpH8.2–8.8

Safety Precautions

•  Handlingboilerwatertreatmentchemicals

•  Samplingsteamgenera7ngsystems  Boilerwatersampling  Highpuritysteamsampling

  Samplingquillexplana7on  Condensatesampling  Coolingcoilexplana7onanddiscussion

•  Boilerhousesafetyconcerns

•  Analy7caltes7ngprecau7ons  Reagenthandling  Handlingprecau7ons

Review Quiz

•  Whydoweworryabouthardness(calciumandmagnesium)intheboiler?

•  Whatarethetwowaysthathardnessismanaged(inmakeupandboilerwater)?

•  Whateffectdoesoxygenhaveontheboiler?

•  Ifmakeupcalciumis1ppm,andtheboilerisrunningat20cyclesofconcentra7on,howmanyppmcalciumisintheboilerwater?

•  Whattwopiecesofsafetyequipmentshouldyouhavewhenhandlingchemicals?