简介:TheproductdistributionandgasolinequalityofFCCprocess,especiallytheolefincontent,heavilydependsonthecatalystperformanceintermsofselective/non-selectivehydrogentransferreactionselectivity.Areliableexperimentalprotocolhasbeenestablishedbyusingn-dodecaneasaprobemoleculetocharacterizetheselectivehydrogentransferabilityofcatalyticmaterials.Theresultsobtainedhavebeencorrelatedwiththeperformanceofthepracticalcatalysts.
简介:Thenaturalconvectionheattransferofa60%sucrosesolutioninaverticalconverging-divergingtube(CD)withregularly-spacedtwistedtapes(RSTT)hasbeeninvestigatednumericallyandexperimentally.TheeffectsofwalltemperatureandnumberofRSTTontheNusseltnumberwerestudiedindetail.Thedistributionsofvelocityandtemperatureinthe60%sucrosesolutionwerestudiedandthesimulatedresultsofCDwithRSTTwerecomparedwiththoseofthesmoothtube.TheinfluenceofRayleighnumberandRSTTontheNusseltnumberwasconductedexperimentally.TheresultsindicatethattheNusseltnumberofthe60%sucrosesolutionobviouslyincreasedwiththenumberofRSTTbutincreasedinconspicuouslywith2andmoretwistedtapes.Thesimulationshowsthatthedistanceforachievinganoptimalheattransferperformanceis46timesthediameterofthetube.Themechanismofthenaturalconvectionheattransferenhancementofthe60%sucrosesolutioninrelationshipwiththeCDandtheRSTTwasanalyzed,andthechangeofaveragetangentialvelocitywiththeaxialdistancewaspresentedtodemonstratethattheenhancementofheattransferwasrealizedmainlybecauseoftheincreaseintangentialvelocity.
简介:TheesterificationoflauricacidwithmethanolcouldbeefficientlycatalyzedbyZrOCl2·8H2O,andthisreactionwasstudiedtodevelopagreenmethodforbiodieselproduction.Theinfluencingfactors,suchasamountofcatalyst,reactiontimeandmolarratioofacidtomethanol,wereinvestigated.TheresultsindicatedthattheZrOCl2·8H2Ocatalystshowedhighcatalyticactivity,andgavea97.0%methyllaurateconversionrateunderthefollowingoptimizedconditions,viz.:alauricacid/methanolmolarratioof1:10,acatalystdosageof4%,andareactiondurationof2hatmethanolrefluxingtemperature.Thecatalystcouldbeeasilyrecoveredwhileitsactivitycouldbewellretainedafterthreecycles.TheZrOCl2·8H2Ocatalystalsoexhibitedexcellentcatalyticactivityfortheesterificationofdifferentfreelong-chainfattyacids(includingnonedibleoilswithhighacidvalue)withdifferentshortcarbonchainalcohols.Therefore,theZrOCl2·8H2Ocatalysthasgoodpotentialforthesynthesisofbiodieselfromlow-costfeedstockssuchaswastevegetableoilsandnon-edibleoils.