欢迎来到人人文库网! | 帮助中心 人人文库renrendoc.com美如初恋!
人人文库网
首页 人人文库网 > 资源分类 > PDF文档下载

外文翻译--过热蒸汽流化床稻谷干燥 英文版.pdf

  • 资源大小:800.65KB        全文页数:7页
  • 资源格式: PDF        下载权限:游客/注册会员/VIP会员    下载费用:5
游客快捷下载 游客一键下载
会员登录下载
下载资源需要5

邮箱/手机号:
您支付成功后,系统会自动为您创建此邮箱/手机号的账号,密码跟您输入的邮箱/手机号一致,以方便您下次登录下载和查看订单。注:支付完成后需要自己下载文件,并不会自动发送文件哦!

支付方式: 微信支付    支付宝   
验证码:   换一换

友情提示
2、本站资源不支持迅雷下载,请使用浏览器直接下载(不支持QQ浏览器)
3、本站资源下载后的文档和图纸-无水印,预览文档经过压缩,下载后原文更清晰   

外文翻译--过热蒸汽流化床稻谷干燥 英文版.pdf

SUPERHEATEDSTEAMflUIDISEDBEDPADDYDRYINGCHAIYONGTAECHAPAIROJA,,ISARESDHUCHAKALLAYAA,SOMCHARTSOPONRONNARITA,SOMBOONWETCHACAMAA,SOMKIATPRACHAYAWARAKORNBATHERMALTECHNOLOGYDIVISION,SCHOOLOFENERGYANDMATERIALS,KINGMONGKUT’SUNIVERSITYOFTECHNOLOGYTHONBURI,SUKSAWAT48ROAD,THUNGKARU,BANGKOK10140,THAILANDBFACULTYOFENGINEERING,KINGMONGKUT’SUNIVERSITYOFTECHNOLOGYTHONBURI,SUKSAWAT48ROAD,THUNGKARU,BANGKOK10140,THAILANDRECEIVED18FEBRUARY2002;ACCEPTED24JULY2002ABSTRACTFLUIDISEDBEDPADDYDRYINGUSINGSUPERHEATEDSTEAMISANEWLYALTERNATIVEAPPROACHINSTEADOFUSINGTHECONVENTIONALHOTAIRTHEMECHANISMOFMASSTRANSFERFORPADDYDRYINGINARANGEOFINITIALMOISTURECONTENTBETWEEN25AND445DBISSTRONGLYCONTROLLEDBYINTERNALMOISTUREMOVEMENTINSIDETHEKERNELANDATWOSERIESEXPONENTIALEQUATIONISSUITABLYUSEDTOEXPLAINITSMOVEMENTDRYINGPARAMETERSINTHEEQUATIONAREAFUNCTIONOFTEMPERATUREANDBEDDEPTHFORTHEPADDYQUALITY,HEADRICEYIELDFROMTHESUPERHEATEDSTEAMDRYINGISMORESUSTAINABLEANDHASHIGHERVALUESTHANTHOSEOBTAINEDFROMTHEHOTAIRDRYING,WHEREASTHECOLOUROFWHITERICEBECOMESDARKER,MAKINGITPOORERQUALITYTHEPERCENTAGEOFWHITEBELLYISSIGNIfiCANTLYAffECTEDBYTHEINITIALMOISTURECONTENTC2112002ELSEVIERSCIENCELTDALLRIGHTSRESERVEDKEYWORDSDEHYDRATION;GRAIN;HEADRICE;QUALITY;SUPERHEATEDSTEAM;WHITEBELLY1INTRODUCTIONPADDYISANIMPORTANTFOODCROPINTHEWORLDTHISCEREALISPROCESSEDINTOSEVERALPRODUCTS,INADDITIONTOASTAPLEFOODBEFOREBEINGPROCESSED,FRESHLYHARVESTEDPADDYNEEDSTOBEDRIEDINORDERTOAVOIDTHEQUALITYDETERIORATIONBYMICROORGANISMSANDRESPIRATIONADRYINGMETHODWHICHISUTILISEDEffECTIVELYFORESSENTIALLYHIGHMOISTUREGRAINS,FOREXAMPLE,PADDY,PARBOILEDRICE,SOYBEANANDMAIZE,ISAflUIDISATIONTECHNIQUE,INWHICHAIRANDSOLIDPARTICLESARERIGOROUSLYMIXEDITHASBEENSUGGESTEDTHATHIGHMOISTUREPADDYSHOULDBEDRIEDQUICKLYTOAPPROXIMATE23DBTOPREVENTTHEYELLOWINGOFRICEKERNELSWHICHISEASILYOCCURREDATHIGHMOISTURELEVELANDTHENSUBJECTEDTOAMBIENTAIRDRYINGINASTORAGEBINUNTILITSMOISTURECONTENTISDOWNTO16DBSOPONRONNARITPRACHAYAWARAKORN,1994SUTHERLANDANDGHALY1990UNDERTOOKANINTENSIVEINVESTIGATIONINTOTHEFEASIBILITYOFUSINGAHOTAIRflUIDISEDBEDDRYINGTECHNIQUEFORPADDYTHEIREXPERIMENTSSHOWEDTHATTHEHEADRICEYIELDRELATEDTOTHEfiNALMOISTURECONTENTTHEHEADRICEYIELDWAS58–61WHENPADDYWASDRIEDFROM282TO205DBBUTWAS15–24FORAfiNALMOISTURECONTENTLOWERTHAN20DBTHEDRYINGMEDIUMWHICHISUSEDFORCARRYINGTHEEVAPORATEDWATERANDflUIDISINGSOLIDPARTICLESCOULDBEHOTAIRORSUPERHEATEDSTEAMSUPERHEATEDSTEAMDRYINGOffERSIMPORTANTADVANTAGESOVERHOTAIRDRYINGITHEENERGYSUPPLIEDTOTHEDRYERCANBEREDUCEDECONOMICALLYBYRECYCLINGTHEEXHAUSTSTEAMINACLOSEDLOOP,IITHEENERGYFROMTHEEXHAUSTSTEAMRESULTINGFROMTHEEVAPORATIONOFMOISTUREINSIDETHESOLIDSCANBERECOVEREDANDUSEDINTHEOTHERSECTIONS,IIIENVIRONMENTALPOLLUTIONORODOUREMISSIONTOTHEATMOSPHERECANBEELIMINATEDSINCEDRYINGOCCURSINACLOSEDCHAMBERWITHOUTAIRTHEGENERALCHARACTERISTICSOFTHEDRYINGPROCESSCHANGESIGNIfiCANTLYWHENSUPERHEATEDSTEAMISUSEDINSTEADOFHOTAIRTHEMAJORDIffERENCESINCLUDEISTEAMCONDENSATIONATTHEMATERIALSURFACEDURINGTHEINITIALDRYINGPERIOD,IIHIGHERDRYINGRATEINSUPERHEATEDSTEAMTHANINHOTAIRATABOVEINVERSIONTEMPERATURE,THETEMPERATUREATWHICHTHEEVAPORATIONRATEOFWATERINTOSTEAMANDHOTAIRBECOMESEQUALYOSHIDAHYODO,1963,IIINOGASfiLMRESISTANCEAROUNDTHESOLIDSURFACETHEREBYINCREASINGTHEMASSTRANSFERRATEJOURNALOFFOODENGINEERING58200367–73WWWELSEVIERCOM/LOCATE/JFOODENGCORRESPONDINGAUTHORTEL/FAX6624708663EMAILADDRESSCHAIYONG_TYAHOOCOMCTAECHAPAIROJ02608774/02/SEEFRONTMATTERC2112002ELSEVIERSCIENCELTDALLRIGHTSRESERVEDPIIS0260877402003357THEUSEOFAHIGHSTEAMTEMPERATUREMAYCAUSEASERIOUSPROBLEMFORTHERMALLYSENSITIVEFOODMATERIALS,SUCHASBROWNING,DISCOLOURATIONANDPROTEINDENATURATIONINSOMECASES,HOWEVER,ITCHANGESTHETEXTURALPROPERTYBENEfiCIALLY;FOREXAMPLE,SHRIMPDRYINGWITHSUPERHEATEDSTEAMPRESENTEDALOWERDEGREEOFSHRINKAGETHANTHATUSINGHOTAIRPRACHAYAWARAKORN,SOPONRONNARIT,JAISUT,2002THEPURPOSEOFTHEPRESENTWORKWASTOMAKETHEPARBOILEDRICEBYASUPERHEATEDSTEAMflUIDISEDBEDDRYERTHEDRYINGCHARACTERISTICSOFPADDYWEREINVESTIGATED,ALONGWITHTHEQUALITIESINTERMSOFHEADRICEYIELD,WHITENESSANDWHITEBELLYTOBEDETERMINED2MATERIALANDMETHODSABATCHSUPERHEATEDSTEAMflUIDISEDBEDDRYERISSCHEMATICALLYILLUSTRATEDINFIG1ITCONSISTEDOFfiVEMAINCOMPONENTSACYLINDRICALCHAMBERWITHANINNERDIAMETEROF15CMANDAHEIGHTOF100CM,A135KWELECTRICALHEATERFORCONVERTINGSATURATEDSTEAMTOSUPERHEATEDSTEAM,ABACKWARDCURVEDBLADECENTRIFUGALFANDRIVENBYA22KWMOTOR,AREVERSEflOWCYCLONEANDASMALLBOILERWITHA31KG/HCAPACITYOFGENERATINGSTEAMAPERFORATEDSHEET,WITH10HOLESPERCM2,WASUSEDFORDISTRIBUTINGTHEDRYINGMEDIUMTHERATIOOFTHEDIAMETEROFDRYERTOGRAINDIAMETERDESIGNEDWASLARGEENOUGHTOMINIMISETHEWALLEffECTHOWEVER,THEWALLEffECTBECOMESIMPORTANTWHENTHERATIOISLOWERTHAN10GEANKOPLIS,1995SUPERHEATEDSTEAMTEMPERATUREWASCONTROLLEDBYAPIDCONTROLLERWITHANACCURACYOFC61C176CBEFOREUSINGSTEAMFORDRYING,HOTAIRWASUSEDFORWARMINGUPTHESYSTEMUNTILTHETEMPERATUREINEVERYPARTREACHEDTHEDESIREDLEVELTHEN,THEAIRWASREPLACEDBYSTEAMTHESTEAMGENERATORGENERATEDTHESATURATEDSTEAMAT106KPAABSOLUTEPRESSUREWITHTHECORRESPONDINGTEMPERATUREOF100C176CWHENTHESATURATEDSTEAMWASflOWEDTHROUGHTHEELECTRICALHEATER,ADDITIONALHEATWASSUPPLIEDTORAISETHESTEAMTEMPERATUREUPTOTHEDESIREDLEVELITWASSUBSEQUENTLYPASSEDTHROUGHTHEflUIDISEDBEDDRYERAFTERTHAT,THESMALLDUSTPARTICLESANDTHEIMMATUREGRAINSSUSPENDEDINTHEEXHAUSTSTEAMWERECOLLECTEDINTHECYCLONEFINALLY,ALLTHECLEANEDEXHAUSTSTEAMWASREUSEDAGAINTHEPADDYWASREWETTEDTOADESIREDMOISTURECONTENTANDTHENKEPTINACOOLROOMATTHETEMPERATUREOF3–5C176CFOR5–7DAYSTOENSUREUNIFORMMOISTURECONTENTTHROUGHOUTTHEKERNELSTHEEXPERIMENTALCONDITIONSWERESETUPASFOLLOWSINITIALMOISTURECONTENTSOF25–45DB,BEDDEPTHSOF10–15CM,SUPERHEATEDSTEAMTEMPERATURESOF150–170C176CATAfiXEDSUPERfiCIALVELOCITYOF31M/STEMPERATURESATDIffERENTPOSITIONSWEREMEASUREDBYCHROMEL–ALUMELTHERMOCOUPLESTYPEKCONNECTEDTOADATALOGGERWITHANACCURACYOFC61C176CAFTERDRYING,PADDYKERNELSWERESLOWLYCOOLEDDOWNTOAMBIENTTEMPERATUREANDKEPTINAPOLYPROPYLENEBAGTHEN,THEYWEREGENTLYVENTILATEDWITHAMBIENTAIRUNTILTHEIRMOISTURECONTENTREACHED16DBFINALLY,A300GSAMPLEWASKEPTINASEALPLASTICBAGFOR2WEEKSBEFORETESTINGFORHEADRICEYIELD,WHITENESSANDWHITEBELLYTHEMOISTURECONTENTOFPADDYWASDETERMINEDBYANELECTRICALAIROVENATATEMPERATURE103C176CFOR72H,ACCORDINGTOAACCMETHOD,1995PADDYQUALITIESINTERMSOFHEADRICEYIELDANDWHITENESSWEREDETERMINEDQUANTITATIVELYANDCOMPAREDTOTHEREFERENCESAMPLEPADDYDRIEDBYTHEAMBIENTAIRTHEMETHODSFOLLOWEDTHEGUIDELINEOFTHEMINISTRYOFAGRICULTURALANDCOOPERATIVES,THAILANDHEADRICEISDEfiNEDASMILLEDRICEHAVINGAKERNELLENGTHATLEAST75OFITSORIGINALLENGTHTHEHEADRICEYIELDWASDEfiNEDASTHEMASSOFWHITERICETHATREMAINSASHEADRICEAFTERCOMPLETEMILLINGDIVIDEDBYTHEMASSOFPADDYSAMPLEFROMTHEEXPERIMENTS,THEHEADRICEYIELDOFFRESHPADDYSAMPLESOBTAINEDEACHTIMEWASDIffERENTANDITWASTHUSDIffiCULTTOCOMPARETHEPADDYQUALITYOBTAINEDFROMDIffERENTDRYINGCONDITIONSTOMAKEACLEARCOMPARISON,THEHEADRICEQUALITYWASTHEREFOREREPRESENTEDASARELATIVEHEADRICEYIELDTHERELATIVEHEADRICEFIG1ASCHEMATICDIAGRAMOFTHESUPERHEATEDSTEAMflUIDISEDBEDDRYER1flUIDISEDBEDDRYER,2HEATER,3FAN,4CYCLONE,5BOILERAND6BYPASSLINE68CTAECHAPAIROJETAL/JOURNALOFFOODENGINEERING58200367–73YIELDISDEfiNEDASTHERATIOOFHEADRICEOBTAINEDFROMARTIfiCIALDRYINGTOTHATFROMTHENATURALAIRDRYINGINADDITIONTOTHEHEADRICEYIELD,THEOTHERTWOQUALITIESOFPADDY,TRANSLUCENCE,WHICHWASDIRECTLYMEASUREDBYWHITENESS,ANDWHITEBELLY,WEREALSOEXAMINEDTHEOPAQUEWHITESPOTATTHEPADDYKERNELCANBELOOSELYDIVIDEDINTOTHEWHITEBELLYANDTHECHALKYGRAINTHEWHITEBELLYARISESFROMINCOMPLETEORPARTIALLYGELATINISEDPADDY,WHILETHECHALKYGRAINHASITSOWNCHARACTERISTICDEPENDINGUPONTHEGENOTYPEOFPADDYANDCANSTILLEXISTINTHEGRAINEVENWITHCOMPLETEGELATINISATIONTHEWHITERICESAMPLESWEREMEASUREDFORTHECOLOURBYUSINGAKETTDIGITALWHITENESSMETERMODELC300BEFOREMEASURINGTHECOLOUROFASAMPLE,THEWHITENESSMETERMUSTBECALIBRATEDWITHAWHITECOLOUREDREFERENCE,HAVINGASTANDARDVALUEOF863THROUGHOUTTHISWORK,THECOLOUROFTHESAMPLEWASREPRESENTEDINTERMSOFTHERELATIVEWHITENESS,WHICHWASDEfiNEDASTHEWHITENESSOFTHESAMPLEFROMTHEARTIfiCIALDRYINGDIVIDEDBYTHATFROMNATURALDRYING3RESULTSANDDISCUSSION31FLUIDISATIONCONDITIONSATfiRST,THEMINIMUMVELOCITYREQUIREDFORflUIDISINGINTHESUPERHEATEDSTEAMWASDETERMINEDBYMEASURINGTHEPRESSUREDROPTHERESULTSARESHOWNINFIG2FORBEDDEPTHSOF10,125AND15CM,INDICATINGTHATTHEMINIMUMSUPERfiCIALVELOCITYFORflUIDISATIONUMF,DETERMINEDFROMTHEPOINTWHERETHEPRESSUREDROPBEGINSTOBECONSTANT,ISINDEPENDENTONTHEBEDDEPTHWITHAVALUEOF26M/SFORASTEAMTEMPERATUREOF150C176CTHISMINIMUMVELOCITYISHIGHERTHANTHATUSINGHOTAIRFORWHICHTHEVELOCITYWAS165M/SASPREVIOUSLYREPORTEDBYSOPONRONNARITANDPRACHAYAWARAKORN1994THEREQUIREDHIGHERflUIDISINGVELOCITYISPROBABLYDUETOTHELOWERDENSITYANDVISCOSITYOFSUPERHEATEDSTEAMTHELOWERPHYSICALPROPERTIESOFSTEAMRESULTINTHERATIOOFTHEVERTICALFORCEONTHEPADDYBECOMINGLOWERFORTHESAMESUPERfiCIALVELOCITYHOWEVER,THEFORCEACTINGONTHEPADDYKERNELINTHEOPPOSITEDIRECTIONCANBEOffSETBYINCREASINGTHESUPERfiCIALSTEAMVELOCITY,THUSREQUIRINGAHIGHERMINIMUMflUIDISINGVELOCITYFORSTEAMASCANBESEENINFIG2,BELOWTHEMINIMUMflUIDISINGVELOCITY,THEBEDISASTATICBED,CORRESPONDINGTOTHEREGIONWHEREPRESSUREDROPHASALINEARINCREASEWITHSUPERfiCIALVELOCITYHOWEVER,ATTHEONSETOFflUIDISATION,THEPADDYWASPARTIALLYflUIDISEDANDITREQUIREDAVELOCITYATLEAST13TIMESHIGHERTHANTHEMINIMUMSUPERfiCIALflUIDISINGVELOCITYTOACHIEVEALLPARTICLEMOVEMENTWHENAPPLYINGTHEERGUNEQUATION1952,THECALCULATEDMINIMUMflUIDISATIONVELOCITYWAS230M/SATATEMPERATURE150C176C,SLIGHTLYLOWERTHANTHEEXPERIMENTALLYDETERMINEDVALUETHISMIGHTBEBECAUSEOFTHEAGGLOMERATIONOFPADDYKERNELSCAUSEDBYTHESTEAMCONDENSATIONFIG3SHOWSTHEMINIMUMflUIDISINGVELOCITYFORAIRANDSUPERHEATEDSTEAM,ANDINDICATESTHESLIGHTDEPENDENCEOFflUIDISINGVELOCITYONTEMPERATURE,BUTTHESTRONGDEPENDENCEONTHECHARACTERISTICflUIDMEDIUM,WITHTHEHIGHERflUIDISINGVELOCITYFORSTEAMOVERAWIDERANGEOFTEMPERATURESTHESMALLEffECTOFTEMPERATUREONTHEflUIDISINGVELOCITYMIGHTBEBECAUSEOFASMALLCHANGEINTHEDENSITYANDVISCOSITYOFTHEMEDIUMSFORTHERANGEOFTEMPERATURECONSIDEREDTHECHARACTERISTICPROPERTIESOFPADDYUSEDINTHECALCULATIONOFTHEflUIDISINGVELOCITYARESHOWNINTABLE1FIG2RELATIONSHIPBETWEENPRESSUREDROPANDSUPERfiCIALSUPERHEATEDVELOCITYATDIffERENTBEDHEIGHTSUPERHEATEDSTEAMTEMPERATURE150C176CFIG3EffECTOFDRYINGMEDIAONTHEflUIDISINGVELOCITYTABLE1PROPERTIESOFLONGGRAINPADDYPHYSICALPROPERTIESEQUIVALENTDIAMETERMM35TRUEDENSITYKG/M31414VOIDEMFSOPONRONNARITPRACHAYAWARAKORN,19940557SPHERICITY;068CTA

注意事项

本文(外文翻译--过热蒸汽流化床稻谷干燥 英文版.pdf)为本站会员(英文资料库)主动上传,人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。 若此文所含内容侵犯了您的版权或隐私,请立即通知人人文库网(发送邮件至[email protected]或直接QQ联系客服),我们立即给予删除!

温馨提示:如果因为网速或其他原因下载失败请重新下载,重复下载不扣分。

关于我们 - 网站声明 - 网站地图 - 资源地图 - 友情链接 - 网站客服客服 - 联系我们

网站客服QQ:2846424093    人人文库上传用户QQ群:460291265   

[email protected] 2016-2018  renrendoc.com 网站版权所有   南天在线技术支持

经营许可证编号:苏ICP备12009002号-5