BTF系统处理硫化氢废气工程设计外文参考文献译文及原文.doc

BTF系统处理硫化氢废气工程设计外文参考文献译文及原文.doc

《BTF系统处理硫化氢废气工程设计外文参考文献译文及原文.doc》由会员分享，可在线阅读，更多相关《BTF系统处理硫化氢废气工程设计外文参考文献译文及原文.doc（24页珍藏版）》请在冰点文库上搜索。

本科毕业设计（论文）

外文参考文献译文及原文

学院：

环境科学与工程学院

专业：

环境工程

年级班别：

2004级

（1）班

学号：

3104008168

学生姓名：

谢辉

指导教师：

陈凡植教授

2008年6月11日

1

Biologicalsweeteningofenergygasesmimicsinbiotricklingfilters

MarcFortunya,c,JuanA.Baezaa,XavierGamisansb,CarlesCasasa,JavierLafuentea,

MarcA.Deshussesc,*,DavidGabriela,1

aDepartmentofChemicalEngineering,UniversitatAuto`nomadeBarcelona,EdificiQ,CampusdeBellaterra,08193Bellaterra,Barcelona,Spain

bDepartmentofMiningEngineeringandNaturalResources,UniversitatPolite`cnicadeCatalunya,Manresa,Spain

cDepartmentofChemicalandEnvironmentalEngineering,UniversityofCalifornia,Riverside,CA92520,UnitedStates

Received25July2007;receivedinrevisedform27October2007;accepted29October2007

Availableonline21December2007

Abstract

Removalofhydrogensulfidefromwasteandenergy-richgasesisrequired,notonlybecauseofenvironmentalhealthandsafetyreasons,butalsobecauseofoperationalreasonsifsuchgaseshavetobeusedforenergygeneration.Abiotricklingfilterfortheremovalofultra-highconcentrationsofH2Sfromoxygen-poorgasesisproposedandstudiedinthiswork.Twolaboratory-scalebiotricklingfilterswereusedtostudythestartupperiodandtodeterminethelong-termperformanceofthegassweeteningprocess.TheinletH2Sconcentrationrangedfrom900to12000ppmvandtwodifferentpackingmaterialswereinvestigated.TherewasnotoxicityeffectobservedevenatathehighestH2Sconcentration,andmaximumeliminationcapacitiesof280and250gH2Sm-3h-1wereobtainedatgascontacttimesof167and180s,respectively.Elementalsulfurandsulfatewerefoundtobethemostabundantend-productsofthebiologicaloxidationofsulfidewhenoperatedundermicroaerophilicconditions.Thebiotricklingfilterwasabletoquicklyrecoveritsnominalperformanceafterdifferentloadincreasesandsystemshutdownssimulatingfieldoperation.Theresultsreportedhereshowthatbiotreatmentcanbeaninterestingalternativetoconventionalgassweeteningsystemsnormallyusedforsuchapplications.

Keywords:

Hydrogensulfide;Gassweetening;Biotricklingfilter;Desulfurization;Fuelgas;Biogas

1.Introduction

Hydrogensulfideisacommonreducedsulfurcompoundfoundinseveralindustrialwastegases.Itiseasilyrecognizablebyitsoffensiverotteneggsodor.However,odornuisanceisnotthemainissueinenergy-richgasessuchasbiogasfromanaerobicdigesterswhichmaycontainH2Sconcentrationsexceeding500ppmvandupto20000ppmv（2%v/v）（WoodcockandGottlieb,2004）.Insuchcases,H2Sremoval,oftencalledgassweetening,isnecessarytoavoidcorrosionofcombustionenginesandSOxgenerationinthefluegases.Thus,removalofH2Sfromwasteandenergy-richgasesisrequired,notonlyforenvironmentalhealthandsafetyreasonsbutalsoforoperationalreasons.

Sofar,themostcommonlyusedtreatmenttechnologyforH2Sremovalisselectiveabsorptioninaminessuchasdiglycolamine,monoethanolamine,methyldiethanolamineorothercompoundsthathaveahighaffinityforH2S（WoodcockandGottlieb,2004）.Althoughtheseprocesseshavebeenextensivelyandsuccessfullyapplied,theyhavemanydrawbackssuchashighenergyandoperatingcostsduetotheregenerationoftheabsorbentphase.Inthiscontext,biologicalprocessesforairpollutioncontrolaregainingpopularity（Deshusses,1997;Devinnyetal.,1999;KennesandVeiga,2001）buthavenotyetbeengenerallyappliedtotreatmentofH2Sinenergy-richgases.

BiologicalH2Sutilizationasenergysourceforlithoautotrophicorganismsisawell-knownprocessthatcanbedescribedwiththefollowingoverallreactions（Eqs.

（2）,（3））.Notethatoxidationtoelementalsulfurcanonlyhappenunderoxygenlimitedconditions,andthatexcessoxygenisrequiredfortheformationofsulfate（Kuenen,1975;WoodcockandGottlieb,2004）.

Biofilters,bioscrubbersandbiotricklingfiltershavebeenproventobeasuitable,environmentallyfriendlyandcosteffectivealternativeforwastegastreatment,especiallyforthetreatmentoflowconcentrationsofH2S（YangandAllen,1994;Devinnyetal.,1999;GabrielandDeshusses,2003a;KimandDeshusses,2005）.However,therehasbeenlimitedsuccessindealingwithhighconcentrationsofH2S（>1000ppmv）usingbiofilters,biotricklingfiltersandbioscrubbersandonlyfewindustrialprocesseshavebeenfullydevelopedforsuchapplication.Amongthem,theThiopaqprocess（Paques,TheNetherlands）,andtheBiopuricprocess（Biothane,USA）aretheonlyonesspecificallydevelopedfortheremovalofhighconcentrationsofH2Sfrombiogasorfuelgas.TheThiopaqprocessisatwo-reactorsystemconsistingofaconventionalcausticscrubberfollowedbyanexpandedbedbioreactorfortherecoveryofthespentcausticandforelementalsulfurgeneration.TheBiopuricprocessisalsoatwo-reactorsystem,whichcombinesaconventionalchemicalscrubberfollowedbyabiologicaltreatmentstep.Littleispubliclyknownaboutthelatterprocess.

Alternativeandsustainableprocessesneedtobedeveloped.Thus,thepurposeofthisstudywastoevaluatethetechnicalfeasibilityoftreatinghighconcentrationsofH2Sinlaboratory-simulatedbiogasorfuelgasusingasinglebiotricklingfilterreactor,andattempttoproducemostlyelementalsulfurwhichcanbeeasilydisposedorrecovered.Unliketheabovementionedcommercialsystems,thetreatmentdemonstratedinthispaperreliesonasinglereactorsystem.AlthoughH2Streatmenthadbeenwidelyreportedinbiofiltersandbiotricklingfilters（YangandAllen,1994;Devinnyetal.,1999;GabrielandDeshusses,2003a;KimandDeshusses,2005）,thepresentstudyisdifferentbecauseitdealswithultra-highH2Sconcentrationsingasesthatareinitiallyoxygen-free.Operationatclose-to-neutralpHwaschoseninordertoimprovetheH2SabsorptioncapacityoftheliquidphasealthoughmanyoftheH2Sdegradingorganisms,likethegenusThiobacillus,haveacidicoptimumgrowingpH（RobertsonandKuenen,1999,2002）.Also,absorptionandoxidationofH2StoelementalsulfurispHneutralasshownbyaddingEqs.

（1）and

（2）.

Twolaboratory-scaleprototypeswithdifferentpackingmaterialswereusedtoevaluatetheperformanceintermsofH2Sremovalefficiency（RE=（Cin-Cout）/Cin）andeliminationcapacity（EC=（Cin-Cout）*Q/V,whereQisthegasflowandVisthebedvolume）.TheratioofSO42-/S0producedunderdifferentoperatingconditionsaswellastherobustnessofthebioreactorwhenexposedtodifferentperturbationswerealsoassessed.

2.Materialsandmethods

BothexperimentalReactorsAandB（seeTable1）werebasedonthesamedesign（Fig.1）butwithslightlydifferentcharacteristics.Theyconsistedofabiotricklingfilterreactoroperatedinanupflow,counter-currentmode,fedwithamimicofbiogasorfuelgascontainingmostlynitrogen,CO2andH2Sasneeded.Althoughthegasdidnotcontainanymethaneorgaseoushydrocarbon,itwasareasonablemimicoffuelgasorbiogasforH2Streatmentpurposes.ThisisbecauseH2Sisdegradedbylithoautotrophicorganismswhichhavebeenshownnottobeaffectedbythepresenceoforganiccarbonsources（CoxandDeshusses,2002）.Evenso,thepresenceofheterotrophicmethanotrophicbacteriawouldresultinsomecompetitionforoxygenwiththeH2Sdegraders.Sincemethaneisonlysparinglysolubleinwater（Sander,1999）andnotwelldegradedinbiofiltersorbiotricklingfilters（Nikiemaetal.,2005）,onlyaslightamountofextraoxygenwouldneedtobesuppliedtocompensateforoxygenconsumptionbyheterotrophicorganisms.Duringtheexperiments,asmallmeteredstreamofair（asrequiredfortheaerobicoxidationofH2S）wasaddedtothebiogasorfuelgasmimic.

Mineralmediumcontaining（gl-1）KNO3,1;KH2PO4,1;K2HPO4,1;NaCl,1;MgSO4,0.2;CaCl2,0.02;traceelements（Pfenningetal.,1981）,1mll-1forReactorAandNH4Cl,1;KH2PO4,1;K2HPO4,1;MgSO4.7H2O,0.5;CaCl2,0.25;traceelements（Pfenningetal.,1981）,1ml1-1forReactorBwasalsocontinuouslyfedtosupplynutrientsandwashoutby-products.InorganiccarbonwassuppliedasCO2viathegasphase（ReactorA）ordissolvedHCO3-intheliquidphase（ReactorB）.

ReactorAwaspackedwithrandomlydumped2*2*2cmcubesofopenporepolyurethane（PU）foam（EDT,Eckental,Germany）.ThePUfoampackingwasdevelopedspecificallyforbiotricklingfiltration（GabrielandDeshusses,2003a;PhilipandDeshusses,2003;KimandDeshusses,2005）.Ithasahighspecificsurfacearea（600m2m-3）andalowdensity（35kgm-3）,arelativelyfinemesh（4–6porespercm）,andalowcompressionstrength（5–10kPa）.ThePUfoambedhadaninitialporosityofabout0.97.

ReactorBwaspackedwithpolypropyleneHDQ-PAC（LantecProductsInc.,CA,USA）witha4*4mmgridopening.TheHDQ-PACisacommonwetscrubberstructuredpackingwithaslightlylowerspecificarea（430m2m-3）thanthefoamandwiderpores.Acylinderofstructuredpackingwascuttotightlyfitinsidethebiotricklingfilterreactor.Theinitialbedporositywas0.88.HDQ-PACwasselectedbecauseofitsstructuralstrengthandbecauseitsopenstructuremayminimizetheretentionofsulfurexpectedfromtheproposedtreatment.

Reactorswereoperatedcontinuouslyforaperiodof3months（ReactorA）and7months（ReactorB）inordertotestarangeofoperatingconditions.Bothreactorswhereinoculatedwithsulfur-oxidizingbiomassinordertospeedupthestartupperiod.ReactorAwaspackedwithPUfoamcubestakenfromalab-scalebiotricklingfiltertreatinglessthan100ppmvH2S,whereasReactorBwaspackedwithcleanHDQ