Measurement techniques in fluidized beds

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1、PowderTechnology102199915±36.MeasurementtechniquesinfluidizedbedsJoachimWertherTechnicalUniÍersityHamburg-Harburg,D21071Hamburg,GermanyReceived26November1997;accepted30July1998AbstractQuantitiesthatneedtobemeasuredingasfluidized-bedsystemsincludesolids

2、volumeconcentrations,solidsvelocitiesandsolidsmassflows,theverticalandhorizontaldistributionofsolidsinsidethesystem,thelateraldistributionofthefluidizinggas,temperaturesandgasconcentrations.Inthepresentpaperanoverviewisgivenonavailablemeasuringtechnique

3、s.Inthefirstsectiontechniquesforindustrialroutinemeasurementsarediscussed.Thesearemainlytemperatureandpressuredropmeasurements.Practicalapplicationsandalsothelimitationsofthesetechniquesareoutlined.Inthesecondsectionmoresophisticatedtechniquesforlocalme

4、asurementsinsidefluidizedbedsystems,whichhavealreadyproventheirsuitabilityinlarge-scaleindustrialreactors,aredealtwith.Examplesincludesuctionprobesformeasurementsoflocalsolidsmassflows,heattransferprobesforthedetectionofdefluidizedzonesandsolidsflowsins

5、idefluidized-bedreactorsandcapacitanceprobesforsolidsconcentrationandvelocitymeasurementsunderhigh-temperatureconditions.Thethirdsectionfinallypresentsadvancedtechniqueswhichareeitherstillunderdevelopmentorwhichareparticularlyintendedforacademicinvestig

6、ationsofbasicfluidizationphenomena.Examplesincludesensortechniques,imagingandtomographicmethods.q1999ElsevierScienceS.A.Allrightsreserved.Keywords:Fluidizedbed;Gas±solidflow;Measurementtechnique1.Introductiondistributionsofthesolidsinsidethesystem,thela

7、teraldistributionofthefluidizinggasand,ofcourse,tempera-Thegas±solidflowinsideafluidizedbedischaracter-turesandgasconcentrations.Suchmeasurementtech-izedbyverydistinctflowstructures.Inlow-velocityflu-niquesareneededintheindustryforidizationnearlysolids-

8、freebubblesareobservedwhichare-monitoringofplantperformanceformedatthegasdistributorandwhicharerapidlycoa--processoptimizationlescingontheirwaythroughthebed.Fig.1a.The-analysisofplantproblemsexistenceofbubblesleadstoabypassofrea