简介:Thesorption-enhancedsteamreformingprocessofmethanol(SESRP-MeOH)toproducehigh-purityH2wasthermodynamicallyandexperimentallystudied.ThermodynamiccalculationsshowedthatataCO2adsorptionratioof95%,productgascontains98.36%H2,32.8ppmCOundertemperatureof130°Candsteam-to-methanol(S/M)molarratioof2.However,withoutadsorption-enhanced,theproductgascontainsnearly74.99%H2with24.96%CO2and525ppmCO.Toverifythethermodynamiccalculationresults,experimentswereperformedinafixed-bedreactorloadedwithcommercialCuO/ZnO/Al2O3methanolreformingcatalystand22%K2CO3-promotedhydrotalciteasCO2adsorbent.Experimentalresultsshowedthat99.61%H2couldbeobtainedbySESRP-MeOHatreactiontemperatureof230°CandS/Mof2.UnderthesameCH3OHconversion,thereactiontemperaturedecreasedbyalmost50°CandH2concentrationincreasedofmorethan20%usingSESRP-MeOHcomparedwithsolelysteamreformingofmethanol.Thecharacterizationoftheadsorbentandcatalystshowedthattheadsorbentshowedgoodstabilitywhilethecatalystwasseriouslysinteredunderthehighregenerationtemperatureoftheadsorbent.
简介:Thesteamreformingoffourbio-oilmodelcompounds(aceticacid,ethanol,acetoneandphenol)wasinvestigatedoverNi-basedcatalystssupportedonAl2O3modifiedbyMg,CeorCointhispaper.Theactivationprocesscanimprovethecatalyticactivitywiththechangeofhigh-valenceNi(Ni2O3,NiO)tolow-valenceNi(Ni,NiO).Amongthesecatalystsafteractivation,theCe-Ni/Cocatalystshowedthebestcatalyticactivityforthesteamreformingofallthefourmodelcompounds.Afterlong-termexperimentat700°CandtheS/Cratioof9,theCe-Ni/Cocatalyststillmaintainedexcellentstabilityforthesteamreformingofthesimulatedbio-oil(mixedbythefourcompoundswiththeequalmasses).WithCaOcalcinatedfromcalciumacetateasCO2sorbent,thecatalyticsteamreformingexperimentcombinedwithcontinuousinsituCO2adsorptionwasperformed.WiththecomparisonofthecasewithouttheaddingofCO2sorbent,thehydrogenconcentrationwasdramaticallyimprovedfrom74.8%to92.3%,withtheCO2concentrationobviouslydecreasedfrom19.90%to1.88%.
简介:这份报纸的目的是在设计下面并且离开设计条件改进最后阶段汽轮机和一台600MW蒸气汽轮机的exhaust兜帽的空气动力学的表演。在操作期间,在汽轮机和exhaust兜帽之间的强壮的流动相互作用在兜帽在流动行为上强加影响并且导致汽轮机的不能令人满意的空气动力学的表演并且用尽兜帽。exhaust兜帽因此有潜力以空气动力学的效率被改善。就在汽轮机和exhaust兜帽之间的流动相互作用而言,更弥漫的结束墙的侧面被优化。联合模型汽轮机和模型用尽兜帽计算和实验被执行验证优化的效果。模型实验证明设计修正导致了全面压力恢复系数的实质的增加。流动和空气动力学的表演照原尺寸最后一台阶段汽轮机并且照原尺寸用尽兜帽被模仿探索流动物理改变到更弥漫的几何学的修正。湿蒸气作为流动媒介被选择。在不同操作条件下面的实际流动地被分析。
简介:Forsyngasproduction,thecombustionoffossilfuelsproduceslargeamountsofCO2asagreenhousegasannuallywhichintensifiesglobalwarming.Inthisstudy,chemicalloopingcombustion(CLC)hasbeenutilizedfortheeliminationofCO2emissiontoatmosphereduringsimultaneoussyngasproductionwithdifferentH2/COratioinsteamreformingofmethane(SR)anddryreformingofmethane(DR)inaCLC-SR-DRconfiguration.InCLC-SR-DRwith184reformertubes(similartoanindustrialscalesteamreformerinZagrosPetrochemicalCompany,Assaluyeh,Iran),DRreactionoccursoverRh-basedcatalystsin31tubes.Also,SRreactionishappenedoverNi-basedcatalystsin153tubes.CLCviaemploymentofMn-basedoxygencarrierssuppliesheatforDRandSRreactionsandproducesCO2andH2Oasrawmaterialssimultaneously.AsteadystateheterogeneouscatalyticreactionmodelisappliedtoanalyzetheperformanceandapplicabilityoftheproposedCLC-SR-DRconfiguration.Simulationresultsshowthatcombustionefficiencyreached1attheoutletoffuelreactor(FR).Therefore,pureCO2andH2OcanberecycledtoDRandSRsides,respectively.Also,CH4conversionreached0.2803and0.7275attheoutletofSRandDRsides,respectively.Simulationresultsindicatethat,3223kmolh-1syngaswithaH2/COratioequalto9.826wasproducedinSRsideofCLC-SR-DR.Afterthat,1844kmolh-1syngaswithaH2/COratioequalto0.986wasachievedinDRsideofCLC-SR-DR.ResultsillustratethatbyincreasingthenumberofDRtubesto50tubesandconsidering184fixedtotaltubesinCLC-SR-DR,CH4conversionsinSRandDRsidesdecreased2.69%and3.31%,respectively.However,thissubjectcausedtotalsyngasproductioninSRandDRsides(inallof184tubes)enhanceto5427kmolh-1.Finally,thermalandmolarbehaviorsoftheproposedconfigurationdemonstratethatCLC-SR-DRisapplicableforsimultaneoussyngasproductionwithhighandlowH2/COratiosinanenvironmentalfriendlyprocess.
简介:中国作为人口众多的发展中国家,能源相对贫乏,以煤炭为主要燃料的能源结构使中国环境问题日益严重,生物质能源作为物质性、易储存的可再生能源,已经成为中国未来能源发展的重点关注对象。受生物质发电技术的进步及中国地理环境多样性的影响,近年来新兴的生物质发电项目展现出新的特点,对该产业效率进行评价时需要考虑新的因素,并采用新的方法,评价结果才能客观,作为改进产业的参考依据。收集中国2010年以来建设的生物质发电项目,选择合适30家生物质发电项目作为样本,分别运用BC2模型、AR模型和分地区AR模型对这30家样本进行评价,发现中国生物质能总体上分布不均,地区差异较大,西南地区、中南地区和华东地区等地是我国生物质能的主要分布区,由于外部燃料资源市场和电网环境较好,因而这些区域产业效率普遍水平较高。对于北方地区生物质产业发展来说,市场和产业环境的改善对效率提高更有帮助。
简介:针对"FBAR(薄膜体声波谐振器)-梁"结构悬臂梁厚度不足、"嵌入式FBAR"结构微加工工艺复杂的缺点,提出了新型"膜片上FBAR(FBAR-on-diaphragm)"结构的微加速度计。其弹性膜片由氧化硅/氮化硅复合薄膜构成,既便于实现与硅微检测质量和FBAR的IC兼容集成加工,也利于改善微加速度计的灵敏度和温度稳定性。对由氧化硅/氮化硅双层复合膜片-硅检测质量惯性力敏结构和氮化铝FBAR检测元件集成的膜片上FBAR型微加速度计进行了初步的性能分析,验证了该结构的可行性。通过有限元模态分析和静力学仿真得出惯性加速度作用下膜片上FBAR结构的固有频率和弹性膜片上的应力分布;选取计算所得的最大应力作为FBAR中压电薄膜的应力载荷,结合依据第一性原理计算得到的纤锌矿氮化铝的弹性系数-应力关系,粗略估计了惯性加速度作用下氮化铝薄膜弹性系数的最大变化量;采用射频仿真软件,通过改变惯性加速度作用下弹性常数所对应的纵波声速,对比空载和不同惯性加速度作用下加速度计的谐振频率,得到加速度计的频率偏移特性和灵敏度。进一步分析仿真结果还发现:氧化硅/氮化硅膜片的一阶固有频率与高阶频率相隔较远,交叉耦合小;惯性加速度作用下,谐振频率向高频偏移,灵敏度约为数kHz/g,其加速度-谐振频率偏移特性曲线具有良好的线性。