【作者】 张璐；

【导师】 张永杰；

【作者基本信息】 东北大学 ， 钢铁冶金， 2019， 博士

【摘要】 生物质能作为可替代清洁能源之一,其利用与推广备受世人关注。开展城市钢厂协同处置生物质废弃物,不仅可以制备多种形式的生物质能,还可以有效减少CO2排放,推进钢铁工业绿色低碳高质量发展。在此背景下,本文从钢厂与城市协同发展,实现资源与能源深度利用出发,依托国内某知名钢厂的重大课题,以城市有机废弃物为主要研究对象,先后开展了热解气化、催化改质制富氢合成气和固废基生物质炭,以及富氢合成气费托合成制液体衍生燃料等一系列基础性实验研究,考察并分析了多级生物质能制备过程中环境负荷伴生物的生成特性,并实验探索了净化技术工艺,为开发钢铁冶金过程中潜在生物质能源和燃料产品,发挥城市钢厂的“废弃物处理、消纳、再资源化”功能,构建环境亲和的钢厂生态工业链,提供理论依据与实验基础。主要研究成果如下:(1)系统研究了城市钢厂协同处理城市生活垃圾制备多级生物质能的技术路线,并基于大量基础实验分析制备及过程催化机理,形成了城市钢厂制备富氢合成气的成套工艺参数。以城市生活垃圾为原料,在气化温度为850℃,催化改质温度为850℃,氧气添加量 ER(Equivalent Ratio)=0.06,水蒸气添加量 S/C(Steam/Carbon,mol/mol)=3.6条件下,对于活性组分Ni含量为15%,助剂Ce添加量为5%的氧化铝负载型催化剂,可获得H2的浓度最高为37.38%,H2/CO比最高可达2.75富氢合成气合成气;对于活性组分Ni含量为15%,助剂Ce与活性组分Ni摩尔比为0.25的炭材料负载型催化剂,可获得H2的浓度最高为37.76%,H2/CO 比值为2.57的富氢合成气。合成气的成分组成均可满足采用费托合成工艺制备液体燃料的原料要求;(2)系统分析了从城市生活垃圾到液体衍生燃料合成的化学转化反应历程,重点揭示了生活垃圾合成液体生物柴油各环节中催化剂的作用机理。生活垃圾经气化催化改质,费托合成工艺可合成出含有主要成分为直链烷烃C9～C21,石蜡和重质烷烃的液体衍生燃料柴油,合成气制备液体衍生燃料过程主要受合成温度、压力、催化剂的组分等操作变量的影响。对于Co/Al2O3催化剂体系,在260℃,1.5MPa,活性组分Co的负载量为8%时,合成的液体燃料组分以直链烷烃C16～C25为主;对于Cu-Co/Al2O3催化剂体系,在240℃,1.5 MPa,Co的负载量为8%,助剂Cu的量为2%时,合成的液体燃料组分以直链烷烃C10～C21为主,同时还有少量的支链烷烃、石蜡和重质烷烃生成,生成的液体产物更加接近柴油的成分组成;对于Ce-Cu-Co/Al2O3催化剂体系,在200℃,1.5 MPa,Co的负载量为8%,助剂Cu的量为2%,Ce的量为8%时,合成的液体燃料组分以直链烷烃C10～C21为主,同时还有少量的支链烷烃、石蜡和重质烷烃生成,生成的液体产物与柴油的成分组成最接近;(3)研制出可适用于生活垃圾气化改质反应的高效含Ce的Ni基催化剂。分别以氧化铝、活性炭材料为载体,以Ni为活性组分、Ce为助剂的负载型催化剂均可有效促进焦油的裂解,其中无论是采用浸渍法还是共沉淀法制备的15%活性组分Ni,5%Ce助剂的氧化铝负载型催化剂对焦油的催化裂解作用最为显著,可使焦油浓度从30.12g/Nm3分别降低到14.65 g/Nm3和14.21 g/Nm3;炭材料负载型催化剂可以有效促进多环芳烃发生苯环的断裂转化成长链的烷烃类物质,有利于焦油的后续处理和利用,但过量的Ce会抑制了催化剂对焦油的催化裂解性能,从促进焦油的裂解转化角度,应当控制助剂Ce与Ni的摩尔比不高于0.5;(4)详细分析了生活垃圾制备多级生物质能过程中固废基生物质炭、焦油、PAHs、H2S、SO2、NH3、NOx等环境负荷物质的伴生特性,探索了有效净化技术,确保了垃圾经热化学转化及费托合成,制备衍生柴油工艺的环境友好性。伴生的固废基生物质炭经850℃水蒸气活化后可作为活性炭用于重金属捕集和有害气体吸附;催化改质可以有效降低焦油的浓度,使焦油中的多环芳烃转化成长链的烷烃类物质;采用UV-Feton法可以促进洗气水中环境负荷物质的降解,在反应时间为40 min时,苯酚的降解率最大为88.80%,在反应时间为50 min时,多环芳烃平均降解率最大为98.50%;活性炭吸附对于SO2、NH3、NOx作用明显,但是对H2S尤其是低浓度的H2S的脱除效果不明显。采用化学吸收法可以有效脱除H2S,其中30%MEDA/GTS复配型脱硫剂对合成气中H2S的脱除效率可达95%以上,可使H2S的浓度低于费托合成工艺、燃气轮机及燃料电池等应用工序对原料气中H2S存在的容许限值(通常限定H2S浓度在75 mg/Nm3以下)。更多还原

【Abstract】 Biomass energy is one of the alternative clean energy sources,and its utilization and promotion have attracted worldwide attention.Developing the synergistic disposal of biomass wastes in urban steel plants can not only prepare various forms of biomass energy,but also effectively reduce CO2 emissions and promote the green,low-carbon and high-quality development of iron and steel industry.In this context,taking the coordinated development of steel mills and cities,realizing the deep utilization of resources and energy as the starting point,relying on a major research topic of a well-known domestic steel plant,this paper took the municipal solid waste(MSW)as the main research object,and carried out a series of basic experimental studies on the preparation of hydrogen-rich syngas and solid waste-based biochar via pyrolysis and gasification of MSW,and the preparation of liquid derived fuels from hydrogen-rich syngas via Fischer-Tropsch synthesis.The paper also studied and analyzed the generation characteristics of environmental load organisms in the process of multi-stage biomass energy preparation,and explored the purification technology process.The research results can provide a certain theoretical research and technical reserve for the development of potentially available biomass energy and fuel products in iron and steel metallurgical process,to realize the "waste disposal,absorption and recycling" function of urban steel mills and build an environment-friendly steel mill ecological industrial chain.The main research results were as follows.(1)The technical route to prepare multi-stage biomass energy for urban steel mills to coprocess MSW was systematically studied.and based on a large number of basic experiments,the preparation and process catalytic mechanism were analyzed,and a complete set of process parameters for the preparation of hydrogen-rich syngas in urban steel mills was formed.With the MSW as the raw material,when the pyrolysis and gasification temperature was 850℃,the reforming temperature was 850℃,oxygen supply ER(Equivalent Ratio)was 0.15,and steam addition S/C(Steam/Carbon,mol/mol)was 3.6,for the alumina-supported catalyst with the active component Ni content of 15%and the additive Ce addition of 5%,the concentration of H2 in the H2-rich syngas reached the highest 37.38%,and the ratio of H2/CO was up to 2.75.For the carbon material-supported catalyst with the active component Ni content of 15%and a molar ratio of the additive Ce to the active component Ni of 0.25,the concentration of H2 in the H2-rich synthesis gas reached the highest 37.76%,and the ratio of H2/CO was up to 2.57.(2)The synthesis chemical conversion reaction process from MSW to liquid-derived fuels was also systematically studied,focusing on the action mechanism of catalysts in the synthesis of liquid biodiesel from MSW.The liquid derived fuel diesel containing linear alkanes C9～C21,paraffins and heavy alkanes can be generated from MSW via gasification and catalytic reforming,Fischer-Tropsch synthesis process.The process of preparing liquid derived fuels from syngas was mainly affected by operational factors including synthesis temperature,pressure,and composition of the catalyst.For the Co/Al2O3 catalyst system,at 260℃,1.5 MPa and 8%loading of active component Co,the components of the synthesized liquid derived fuel were mainly straight-chain alkanes C16～C25.For the Cu-Co/Al2O3 catalyst system,at 240℃,1.5 MPa,8%loading of active component Co and 2%loading of promoter Cu,the main components of the synthesized liquid derived fuel were linear alkanes C10～C21,and a small amount of branched alkanes,paraffins and heavy alkanes were also generated,and the composition of liquid products was closer to the composition of diesel oil.For Ce-Cu-Co/Al2O3 catalyst system,at 200℃,1.5 MPa,8%loading of active component Co,2%loading of promoter Cu,and 8%loading of the promoter Ce,the main components of the synthesized liquid derived fuel were linear alkanes C10～C21,and a small amount of branched alkanes,paraffins and heavy alkanes were also generated.The composition of the liquid products was the closest to that of diesel oil.(3)The highly efficient Ce-containing Ni-based catalysts suitable for gasification and reforming of MSW were developed.The supported catalysts with alumina or activated carbon materials as carriers,Ni as active component and Ce as promoter,can effectively promote the cracking of tar.Among the catalysts,whether alumina-supported catalysts were prepared by impregnation method or co-precipitation method,when the active component Ni content was 15%,and the promoter Ce content was 5%,the catalytic cracking effect of the catalyst on tar was the most significant,and and the tar concentration was reduced from 30.12 g/Nm3 to 14.65 g/Nm3 and 14.21 g/Nm3,respectively.Carbon material-supported catalysts can effectively promote the breakage of the benzene ring in the polycyclic aromatic hydrocarbons to convert into the alkane substances in the extended chain,which was beneficial to the subsequent treatment and utilization of the tar.However,excessive amount of Ce can inhibit the catalytic cracking performance of catalysts for tar.From the point of view of promoting the cracking conversion of tar,the molar ratio of Ce to Ni should be controlled to be no higher than 0.5.(4)The associated properties of solid waste-based biochar,tar,PAHs,H2S,SO2,NH3,NOx and other environmental load substances in the preparation of multi-stage biomass energy from MSW were analyzed in detail,and effective purification technologies were explored to ensure the environmental friendliness of the derived diesel preparation by thermal chemical conversion from MSW and Fischer-Tropsch synthesis process.The associated solid waste-based biochar can be used as activated carbon for heavy metals capture and harmful gas adsorption after being activated by steam at 850℃.Catalytic reforming can effectively reduce the concentration of tar,and convert polycyclic aromatic hydrocarbons in tar into alkane species in the chain.The UVFeton treatment can promote the degradation of environmental load substances in the scrubbing water.When the UV-Feton reaction time was 40 minutes,the degradation rate of phenol reached 88.8%,and the average degradation rate of polycyclic aromatic hydrocarbons can reach 98.5%when the reaction time was 50 minutes.Activated carbon adsorption had obvious effect on the removal of SO2,NH3,NOx,but had no obvious effect on the removal of H2S,especially on the removal of low concentration of H2S.Chemical absorption can effectively remove H2S.Among them,30%MEDA/GTS compound desulfurizer can remove more than 95%of H2S in syngas,which can make the concentration of H2S lower than the allowable limit of H2S in feed gas in Fischer-Tropsch synthesis process,gas turbine and fuel cell processes(usually these processes limited the concentration of H2S to less than 75 mg/Nm3.).更多还原