12.2 Heat exchanger design
On a purelyheattransferbasis,the designof any heatexchangeris a balance
between achieving the desiredthermal duty and the associated capital and
runningcosts. The increasingcostof energy has also led to a far greater
implementationof heatrecoveryand process integrationapproaches.
Table12.1 Classificationof maintypesof foodindustryheatexchangers
Generictype Optionsavailable Otherpotentialoptions
Plate Standardgap/widegap Platesgasketedor welded
Conventionaldesign,fluidsA and B
flowthroughalternatechannels
Dualplate
Each`plate'consistsof two plates
withan air gap in between
Platein shell
Platepackwithalternateplates
ungasketedand wholepackinstalled
withina shell.Allowslargervolumes
of vapourto be handledthan
conventionaldesign.Liquidflows
throughgasketedchannels
Scraped
surface
Rotary
Bladeson rotatingshaftscrape
internalheattransfersurface.External
jacketfor heating/coolingmedium
Horizontalor vertical
orientation
Linear
Scraperson shaftmovein linear,
reciprocatingmotion
Horizontalor vertical
orientation,multipletubes
availablewithinshell
Tube
(straight)
Monotube
A singletubewithina tube
Multipletubein tube
A singleshellwithinwhichthereare
a numberof smallerdiametertubes
Tripletube
Threeconcentrictubes,fluidA flows
throughinnertubeand outerannulus,
productB thoughinnerannulus
Tubesmaybe smoothor
corrugated.Angleof
corrugationrelativeto the
verticalcan be variedto
alterheattransfer
characteristics
Tube
(coiled)
Monotube
A singletubewithina tube
Tripletube
Threeconcentrictubes,fluidA flows
throughinnertubeand outerannulus,
productB throughinnerannulus
Improvingthe hygienicdesign of heatingequipment 213