简介:bamboo(Phyllostachysedulis)residuewassubjectedtosteamexplosiontreatmenttoproducesuperiorfibersforbinderlessboards.Then,ligninwasisolatedfromextract-freebamboomeal,steamexplodedpulp,andbinderlessboardswithcharacteristicsbeingdeterminedbythermo-gravimetry(TG),differentialscanningcalorimetry(DSC),andfouriertransforminfraredspectroscopy(FTIR).Resultsshowedthat:1)theyieldoflignindirectlyextractedwithdioxane-waterfromsteamexplodedbamboopulp(SEBPL)andbinderlessboard(SEBBL)washigherthanthatofmilledbamboolignin(MBL).Also,theyieldofSEBBLwaslowerthanthatofSEBPL.2)FTIRresultsshowedcleavageofesterandetherbondsbetweenligninandp-coumaricacidduringsteamexplosiontreatment.3)SEBBLshowedtwoglasstransitionsat115℃and200℃,whileMBLgaveoneglasstransitionsat155℃.And4)themodulusofrupture(MOR)andmodulusofelasticity(MOE)decreasedwithanincreaseinsteamingtime;whereasinternalbonding(IB)increased.InallcasesthedimensionalstabilityofboardsdidnotexceedthemaximumrequirementsfortypeGB/T11718-1999.
简介:Anaccurateandcompletegeometricmodelwasconstructedtosimulatethecombustion,flowandtemperatureenvironmentintheradiantsectionofthesteamcrackingfurnace.Simulationofflowandradiationstatushasutilizedthestandardk-εmodelandP1model.Thefinite-rate/eddy-dissipation(finite-rate/ED)combustionmodelandnon-premixedcombustionmodelwerebothusedtosimulateaccuratelythecombustionandtheoperationstatusofthesteamcrackingfurnace.Threedifferentsurfacesofthesteamcrackingfurnacewereobtainedfromthesimulation,namely:thefluegastemperaturefieldoftheentrancesurfaceinlongflameburners,thecentralsurfacelocationoftubes,andthecrossoversectionsurface.Detailedinformationonthefluegastemperatureandthemassconcentrationfractionofthesedifferentsurfacesinthesteamcrackingfurnacecanalsobeobtainedbythesimulation.Thispaperanalyzedandcomparedthesimulationresultswiththetwocombustionmodels,estimatedtheoperationstatusofthesteamcrackingfurnace,andreportedthatthefinite-rate/EDmodelisappropriatetosimulatethesteamcrackingfurnacebycomparingkeysimulationdatawithactualtestdata.Thisworkhasalsoprovidedatheoreticalbasisforsimulatingandoperatingthesteamcrackingfurnace.