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CH4-1SedimentationandFiltration(homogeneoussystem)(non-homogeneoussystem)()Dispersedphase()continuousphase()1CH4-1(1)Itisamainstageintheproduction(2)Increasingpurityofproducts(3)extractingvaluablematters(4)RemovingharmfulmattersGravitySedimentation(gravitysettling)41Movementofparticlesinfluid4.1ATheforcessubjectedbytheparticlesduringtherelativemovementbetweenparticlesandfluid2CH4-141(dragforce).41StockesFd=3ud(N)(41)µ:Pasdm;ums-1FdN(41)3CH4-1242422ududFd⋅⋅=ρρµπkgm-3µρduRep=42dAπ=epR24=ξRep,Am22uAFdρξ=(42)epR24=ξ(42)(41)Rep42s=14CH4-142Rep(1)(Rep1)epR24=ξ(43)(2)(1Rep500)6.05.18epR=ξ(44)(3)(500Rep1.5105)=0.4(45)StockesAllenNewtonStockes4.1BSedimentationVelocity1.Freesettlingofthesphericalparticles5CH4-1(freesettling)pdmtuFgFbFd43FdFbmg43dbgFFFddum−−=τ4—6agdFPgρπ36=,4—6bgdFbρπ36=,4—6c6CH4-12422udFdρπξ⋅⋅=4—6d243udgFFFddumpppdbgρξρρρρτ−−=−−=4—6euuududtuu0du/dt=0u0(terminalvelocity)du/dt=0u=u0(46)()ξρµρρ340gdup−=4-6(43)(44)(45)u0(1)Stockes7CH4-1()µρρ1820gdp−=u(47)(2)Allen()754.04.06.10154.0−=µρρρgdup(48)(3)Newton()ρρρgdgp−=30u(49)2Calculationofsettlingvelocityu0(47)(48)(49)Rep(46)Rep(47)(49)Repu0u0(1)trialanderrormethodu0Rep42(46)uu0u00u′0′0u′(2)(Repeatverificationmethod)8CH4-1u0u0u0RepRepu0Rep(3)Directmethodu0KRep(48)()034ugdPρρρξ−=(410)(410)u022=µρduRepξ2epR()22234µρρρξgdRpep−=(411)RepξRep2epR()312−=µρρρgdKp(412)3234KRep=ξ(413)KξKRep(412)u0K2epR9CH4-1(47)u0KRep()1818323KgdRpep=−=µρρρ318epRK=(414)Rep=1K=2.62(Stockes)(49)Rep=500(Newton)K43.6KK2.622.62K43.6K43.6u0Ku0415m201010kg/m31035kg/m32.1210-3PasAllen10CH4-1()()()()smgdup/1032.11012.2103581.910351010105154.0154.05756.064.06.16754.04.06.10−−−×−=×××−×××=−=µρρρ11022.31012.210351032.110553560×=×××××==−−−−µρduRepStockes()()smgdup/1061.11012.21881.910518732620−−−×−=××××=−=µρρ11093.31012.210351061.110573760×=×××××==−−−−µρduRepu0-1.6110-7ms-12K()()()62.21090.11012.281.91035101035.1105375236312×=××−×××=−=−−−µρρρgdKpK2.62u011CH4-1=-1.61X10-7m/s3.TheinfluencefactorsonthesettlingvelocityStockes1diameterofparticles(2)(Viscosityofdispersedmedium)(3)Densitydifferencebetweentwophases12CH4-1(1)ShapeofparticlessSRep42Repd(2)(Walleffect)(3)(hinderedsettling)42Gravitysettlingofthesuspension(clarifying)(thickening)13CH4-14.2ABatch-typethickener44(1)44(2)ABCABBCABBACBBACC14CH4-1h0m;Vm3t0s;u0ms-1;A0m2qv()()-130000smtAhtVqV==h0=u0t0(415)()-1300smAhqV=4-1644(1)(2)HT4.2B15CH4-145451.ThresholdofVelocityucFdF16CH4-12422udFdρπξ⋅⋅=spfgdFµρρπ)(63−=uLms-1FfFdFFd=FuLuCspcgdudµρρπρπξ)(624322−=⋅()ξρµρρ34spcgdu−=(417)uLuLuc2.SizeofthickenerLh04500uuhLL≥00hLuuL≤4-18(420)17CH4-1(m3s-1)(419)Lvubhq0=(418)000000AubLuhLubhqv==≤m3s-1(420)bm;A0m24.2CContinuousthickener4610100m4618CH4-14646u0u1u0u1(421)G0-kg/sC0kg/kgCRkg/kgA0m2kgm-31()ρRvvCCqq−=0(m3s-1)(422)2.u119CH4-1()0001ACCqAquRmVρ−==(ms-1)(423)3.A0:(421)()000uACCqRm≤−ρ()000uCCqARmρ−≥(m2)(424)4Capacityofthickener422424()000uACCqRmV≤−=ρq42543Gravitysettlingofgasoloid(gasoloid)(settlingchamber)4.3AErectsettlingChamber20CH4-147u1u0u1u0(426)D(426)102014uDqAquvvβπ===(427):Qm3s-1A0m20.030.050013.14uquqDvvβπβ==(m)(428)H1=(1.02.0)D(m)(429)3mmH1=(1.01.5)DH1=(1.51.8)DH1=(1.52.0)DH221CH4-1()22ϕtgdDH−=(m)(430)d=4040474.3BHorizontalsettlingChamber48(1)48(2)LmuLms-1;22CH4-1tLs;H0mu0ms-1t0s;WmLLuLt=000uht=00uhuLL≥(431)qs0ttL≥0bhquvL=(432)(431)bLquv≥0(433)(434)100%dcuocbLquvC=0(434)stockes(434)(47)criticaldiameter23CH4-1()bLqgdVPC⋅−=ρρµ18(435)uocdcVSH0VSuocdcH0u0H0L(1)(2)24CH4-2filtration(filtration)44TheConceptsofFiltration(filtrationmedium)(slurry)(filtercake)(filtrate),491.TheMethodsofFiltration(1)DeepBedFiltration(0.1%)(deepbedfiltration)1CH4-2(2)CakeFiltration(1%)BridgePhenomenon4—9410(Filter-cakefiltration)2.DrivingforceandDragforceoffiltrationThePressureDifference2CH4-2(1)gravityfiltration50KPa(2)Pressingfiltration500KPa(3)Vacuumfiltration85KPa(4)Centrifugefiltration3CH4-23.FiltrationProcedure1FilteringStage(2)FilterCakeWashing(3)(Dehydrationoffiltercake)(4)(filtercakeunloading)4CH4-24.FilteringMediumintercept1TheStructureofMediumShouldbePorous2TheStrengthoftheMediumshouldbehighenoughtosupportthefiltercake3TheSurfacepropertyofthemediumshouldbegoodenoughtomakethefiltercaketobeunloadedeasily(1)FabricMediumstainlesssteelBrasswiresNickelwires(2)GranularmediumgravelfinesandActivatedcarbon(3)Poroussolidmedium5CH4-25.Filteringaid(filteraid)(1)diatomite(8095)%SiO2(2)perlite100070%SiO2(3)asbestos(4)charcoalpowdersawdust6CH4-245Thebasictheoryoffiltration4.5AThebasicequationoffiltration(filtrationrate)m3s-1(filtrationvelocity)ms-1Adtdvdv/dtdv/(Adt)()=7CH4-21.FilteringVelocityandfiltercakeresistancePoiseuillelpducµ3221∆=(4—36):ums-1d1mPcPaPaslmudv/dtdV/(Adt)udV/(Adt)d1∆Pc/(32µl)dllLlLLld2r’lpdKAdtdVcµ3221∆′=(ms-1)8CH4-232121dKr′=′LrpAdtdVcµ′∆=(437)r’m-2rdV/(Adt)PLµ′cK’—Lrµ′2.FilteringVelocityandfiltermediumresistanceLeLerLePm(439)emLrpAdtdVµ′∆=(ms-1)(438)3.TheBasicEquationsofFiltration(437)(438)9CH4-2P=∆Pc+∆Pm,)(eLLrpAdtdV+′∆=µ(ms-1)(439)XLVLA∝xV(m)(4—40)AxVKL/′′=LeVeVem3AxVKLee/′′=(4—40a)439rKr′′