profitable aquafeed moisture control

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January | February 2013 Profitable aquafeed moisture control The International magazine for the aquaculture feed industry International Aquafeed is published six times a year by Perendale Publishers Ltd of the United Kingdom. All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2013 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1464-0058 INCORPORATING FISH FARMING TECHNOLOGY

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Aquafeed producers are losing about $4 to $10 per ton of product produced in terms of lost production, higher energy consumption and lowered product quality. These losses can be recovered by substituting a more effective moisture (MC) sensing and control technology for currently used traditional MC sensing and control.

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Page 1: Profitable aquafeed moisture control

January | February 2013

Profitable aquafeed moisture control

The International magazine for the aquaculture feed industry

International Aquafeed is published six times a year by Perendale Publishers Ltd of the United Kingdom.All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2013 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1464-0058

INCORPORAT ING f I sh fARm ING TeChNOlOGy

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64 | InternatIonal AquAFeed | January-February 2013

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Aquafeed producers are losingabout $4 to $10 per ton ofproduct produced in terms oflost production, higher energy

consumption and lowered product quality.Theselossescanberecoveredbysubstitut-ingamoreeffectivemoisture(MC)sensingand control technology for currently usedtraditionalMCsensingandcontrol.

The control problem Two main problems prevent traditional

MC sensing and control technology frombeing effective. Firstly, the lack of timelyand accurate MC data upon which to basecontrol action (poor MC sensing). Secondly,theinabilitytocorrectlyadjustforevaporativeloadchangesenteringwiththefeed.

Figure1showsatypicalnormalMCdis-tributioncurveproducedbytraditionalMCsensing and control technology. The curveisrelativelywideasaresultoftheeffectofhigh MC standard deviation. It is obviousthat thewider theMCvariation the lowerthe target mean MC must be to preventproduction of wet product. Consequently,use of currently available control technol-ogy forcesmanufacturers tooverdry theirproducts which causes significant costs interms of lower production, higher energyusage,andpoorerquality.Figure1illustratestheeffectofpoorMCsensingandcontrolonMCvariation.

The control solutionLosses caused by poor MC sensing

and control may be recovered if the MCvariation (standard deviation) is reduced

such that themeanMCcanbemaximizedwithout exceeding the upper specificationlimit(USL).Fortunately,asolutionforpoorMC sensing and control was supplied bythederivationofaMCsensingandcontrolmodel from first principles. The Delta Tmodel:

MC=K1(ΔT)p–K2/Sq

relates the product MC exiting a dryerto the temperature drop (ΔT) of hot airafter contact with the wet product and theproductionrateorevaporative load(S).Themodel solved the two main problems withMCsensingandcontrolbyproducing.Firstly,a rugged, reliable ‘inside-the-dryer’ moisturesensor; and secondly, a new and powerfulcontrolalgorithmthatpreciselyadjuststhesetpointforevaporativeloadchanges.

A new type of MC sensorFigure 2 describes how the Delta T MC

sensor continuously measures the MC of

aquafeed inside the harsh environment of adryerwhileitisbeingdriedwithabeltdryer.

As illustratedbyFigure2,patentedDeltaTtechnologyinventedanewtypeMCsensorthatcanbeinstalled‘inside-the-dryer’whichreducesthe dead time (time to detect a disturbanceenteringwiththe feed)byat least30percent.Sincedead time isdirectlyproportional to theproduct standard deviation, use of this ‘inside-the-dryer’sensorreducesthestandarddeviationatleast30percentbelowthatachievedbyuseofcurrentlyusedMCsensingmethods.ItshouldbenotedthatuseofrawDeltaTdatawillnotwork—it must be processed by the modelbeforeuse.Figure3illustratestheadvantageofreducingdeadtimeforaquafeeddrying.

Threepossiblelocationsareshownforinstall-ingtheMCsensor.Deadtimeforeachinstallationpoint is the time it takes for the individualMCmethodtodetectachange inevaporative loadentering with the feed. The lowest dead timeis14minutes for theDeltaTsensor insidethedryer;thenextlowestdeadtimeis20minutesforaMCmeterlocatedatthedryerexit;thelongest

Profitable aquafeed moisture control

by John Robinson, President, Drying Technology Inc, USA

Figure 1: Typical MC distribution curve produced by poor MC sensing and control

Figure 2: Delta T ‘inside-the-dryer’ MC sensor

Figure 3: Delta T reduces dead time on belt dryer

14 | InternatIonal AquAFeed | January-February 2013

FEATURE

January-February 2013 | InternatIonal AquAFeed | 15

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99999999

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14 | InternatIonal AquAFeed | January-February 2013 January-February 2013 | InternatIonal AquAFeed | 15

FEATURE

Extruder OEE for the Production of Fish FeedExtruder OEE for the Production of Fish Feed

AMANDUS KAHL GmbH & Co. KG, Dieselstrasse 5-9, D-21465 Reinbek / Hamburg, Phone: +49 40 727 71 0, Fax: +49 40 727 71 100, [email protected] www.akahl.de

Please visit us at:

V.I.V. ASIA

Stand H104 D032

Page 6: Profitable aquafeed moisture control

Volume 16 / Issue 1 / January-February 2013 / © Copyright Perendale Publishers Ltd 2012 / All rights reserved

Page 7: Profitable aquafeed moisture control

dead time is 30min-utes for MC samplestakendownstreamofthe dryer and ana-lyzed by a laboratoryinstrument.

For the aboveconditions,theDeltaTaccomplishesdeadtime reductions of30 percent and 53percent below thatfor the moisturemeter method andthe laboratory MCsample methodrespectively. Thestandard deviationreductions wouldalso be reduced 30percentand53per-centrespectively.

A new MC control algorithm

As a result ofits theoretical basis,theDeltaTtechnol-ogy provides a newcontrol algorithmthat enables precisecalculationofthesetpoint necessary tomaintain the target

MC in spiteof frequentchanges inevapora-tive load entering the dryer with the feed.Proprietarymethodsareusedinadaptingthemodeltothedryerandproduct.

Application of Delta T to aquafeed manufacture

Theabove-mentioned reduction in standarddeviationenablesthetargetMCtobeincreasedby0.5percenttoasmuchas1.25percentwith-out fearofproducingwetproductwhichmightmoldintransitorstorage.Figure4showssche-matically how reducing the standard deviationenablesthemeanMCtobeincreasedbyshiftingtheDeltaTcurverightwarduntiltheupper+3standard deviation points (USL)of both curvescoincide.ThedifferenceinmeanMCsrepresentstheeconomicgainfromusingDeltaTtechnology.

Results and conclusionsFrom10to25lbsofadditionalwatercanbe

safelysoldwiththeproductpertonofproductproducedwithoutexceedingtheupperspecifica-tionlimitusingthisnewtechnology.Thereturntotheaquafeedmanufactureris$4to$10pertonofproductforawholesaleproductpriceof$800per ton. In addition, energy savings of approxi-matelyfourtosevenpercentpossible.TheDeltaThasbeensuccessfullyappliedintheUSforMCsensingandcontrolofmanyproducts, includingaquafeedusingaBeltomaticconveyordryer.

More InforMatIon:Website: www.moisturecontrols.com

Figure 4: Delta T MC control allows mean MC to be maximized without exceeding USL

Figure 5: Outside view of Delta T MC system

Current

Delta T

MC

16 | InternatIonal AquAFeed | January-February 2013

FEATURE

®

Corporate offiCeP.O. Box 8 • 100 Airport Road

Sabetha, KS 66534, USAPhone: 785-284-2153

Fax: [email protected]

www.extru-techinc.com

BREAKTHROUGHin Aquafeed Technology

Take this opportunity to visit www.extru-techinc.com/at to see the next level in aquafeed technology.

demAnd

GEnUinEExTRU-TEcHOem PARTS

Many leading aquafeed manufacturers in the industry count on Extru-Tech to engineer the perfect aquafeed production solution.

industry leading equipment and engineered production advantages will give you the upper hand over the competition. could you use a cost effective improvement in performance and finished product quality? contact one of the Aquafeed consultants at Extru-Tech today at 785-284-2153.

ET-233A.indd 1 12/27/12 10:51 AM

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16 | InternatIonal AquAFeed | January-February 2013

No hollow spaces | No cross contaminationExcellent cleaning access | Filtered air inletTemperature control | Moisture control | Cleaning in Place

C L E A N C O N T R O L

Swivel Valve Cooler MkII

c o o l a n d d r y

clean and lean

[email protected]

www.geelencounterflow.com

T +31-475-592315

Geelen Counterflow Holland / USA / Argentina / China

Page 9: Profitable aquafeed moisture control

www.aquafeed.co.uk

LINKS

• Seethefullissue• VisittheInternationalAquafeedwebsite

• ContacttheInternationalAquafeedTeam

• SubscribetoInternationalAquafeed

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Volume 16 I s sue 1 2 013 - J anuary | f ebruary

INCORPORAT ING f I sh fARm ING TeChNOlOGy

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