pH monitoring in alcoholic fermentation

•Distillingtraditionalalcoholsfromsugarbeetsyrups•InlinepHmeasurementforprocesscontrol•Costsavinginstallationofsensorwithintegratedtransmittertechnology

1. Background

TereosFranceisaworldleadingproducerofsugarandoneofEurope’smainmanufacturersofstarch-basedproductsandalcohols.Amongothers,thecompanyoperatesseveraldistilleriesofwhichoneislocatedinValdesMarais,inNorthernFrance,whereagriculturalrawmaterialsareturnedintotraditionalalcohols.Priortothemaindistilleryprocesses,low-puritysyrupswithasugarcontentof55…65%areextractedfromsugarbeetandsubsequentlytransformedintoalcohol(“wine”)of5…13Vol.-%forfurtherprocessing.Thefermentationprocessiscarriedoutin7tanks.Forthedesireddegreeofalcohol,thesetanksarekeptat32…37°C/90…99°F.Thisway,thedistilleryproducesabout200m³of“wine”perday.

2. Measurement requirements

ThebestfermentationconditionismaintainedatapHvalueofbetween2.5and4.ForthisreasonitisveryimportantthatthepHvalueofthelow-puritysyrupsinthetanksismonitoredonaregularbasis.ThecustomerthereforeestablishedapHmeasurementcycle(7samples,1cleaning;cycletime:approx.1hour).Samplestakenmanuallyalsogetcheckedinalabeverytwohours.IfthepHvaluerisesabove4.5,sulfuricacidandphosphoricacid(nutrient)havetobeaddedtopreventthegrowthofbacteria,whichcancontaminatethealcoholsolution.TereospreviouslyusedapHsensorfromanalternativesupplierforthisapplication,howeverthesensorandexternaltransmitterwereaffectedbyhydraulicshockscausedbythemedium.Theliquidenteredthetransmitterviathecableglandanddamagedthedevice.Thisinterruptedprocessmonitoringwhichalsohadanimpactontheaciddosageasthedosingpumpstoppedworking.TheriseofthepHvaluecouldnotbepreventedeffectivelyandtheperformanceofthedosingpumpcouldnotbecontrolled.ThereforethecustomerlookedforanewsolutioncapableofmeasuringpHreliablyathighpressureconditionsofaround5barg/72.5psig.

APPLICATION REPORT Food & Beverage

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3. KROHNE solution

KROHNEofferedSMARTPATPH2390.ThepHsensorwasinstalleddirectlyintothepipe.Theruggedsensordesignmakesthissensortypesuitableforthisapplicationbecauseofthehighpressureresistanceofupto6.9bar/100psi.Itcanbeeasilyadaptedtosuchharshapplicationswithalcoholicsolutions.

The2-wirelooppoweredSMARTPATPHsensorfeaturesintegratedtransmittertechnology.Theentiretransmittertechnologyisminiaturisedandfitsintothesensorhead,eliminatingtheneedforanexternaltransmitter.TheSMARTPATPHsensorstoresalldataandsendstheseasbidirectionaldigitalsignalswith4...20mA/HART®directlytoaPLCthatcontrolsthedosingpump.

4. Customer benefits

TereosnowbenefitsfromastablepHvaluethathelpsthemmaintainthebestfermentationconditionsfortheiralcoholproduction.AnaccuratedosingofnutrientsisguaranteedincasethepHvaluerisesabove4.5.ThedosingpumpnolongerstopsduetoadamagedpHsensoranditsperformacecannowbereliablymonitored.Themechanicalprotectionofthesensorpreventsproductentryandguaranteesoperationalsafety.

GiventhattheSMARTPATPH2390featuresintegratedtransmittertechnology,theinvestmentcostsofthecompletemeasuringloopissignificantlyreducedincomparisontothepreviousmeasuringsystemthatneededaseparatetransmitter.Maintenanceandcostsarealsoreducedbecausethesensorcanbeconfiguredandcalibratedofflineinthelaboratoryundercontrolledconditions.Calibrationerrorsandcumbersomesensorhandlingon-sitearenolongeranissue.Thesensorcanbecleanedandregeneratedtoextendthelifetime.

TereosstandstogainfromthesinglesourcesupplierKROHNEthatdoesnotonlyprovidethesensorsbutthewholerangeofprofessionalequipment(e.g.buffersolutions)aswellasconsultingservices.

5. Product used

SMARTPAT PH 2390• 2-wirelooppoweredsensorwithintegratedtransmittertechnology• Specialsensordesignforharshapplications• Lowmaintenancecostandlongservicecycle• LargePTFEdiaphragmforreliablepHmeasurement• Doublejunctionforextendedlifetimeandawideapplicationrange• WithintegratedPt1000andstandardVP2connector

Contact Wouldyoulikefurtherinformationabouttheseorotherapplications?Doyourequiretechnicaladviceforyourapplication?application@krohne.com

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SMARTPAT PH 2390 installed between ahydrometer (left) and a redundant probe (right)