【作者】 张宏雷；

【导师】 闫红； 朱国才；

【作者基本信息】 北京工业大学 ， 生物医学工程， 2013， 博士

【摘要】 生物质作为一种分布广泛、储量丰富、可再生和环境友好的资源而受到关注。生物质热解产物主要是由固态、液态和气态产物组成的强还原性物质，可用于金属和非金属氧化物的还原反应，特别是在矿物质的还原方面具有广泛的应用。因此，本文以生物质代替传统煤炭，对其热解还原制备一氧化锰进行系统的研究，提出一种高效、经济和环保的一氧化锰制备新工艺。本研究不但可拓宽生物质的应用范围，为一氧化锰提供高效的制备新技术，而且对于缓解日趋严重的能源危机、环境问题和人类健康等具有重要的理论及应用意义。首先，以稻秆、锯末、麦秆、玉米秆和竹粉作为生物质原料，利用热重分析方法研究其热解过程；根据Coats-Redfern的一级动力学方程，建立生物质热解动力学模型；利用气相色谱、电镜能谱和红外光谱等分析方法，对生物质热解的气、液、固产物进行分析，确定其基本组成。结果表明生物质热解过程可分为脱表面水、脱结合水、快速热解和缓慢热解四个阶段；生物质热解过程符合分段一级动力学模型；生物质热解的气态产物主要由CO2，CO，H2，CH4，C2H4和C2H6组成，固态产物主要由C和O元素组成，而液态产物是由各类有机物组成。第二，选取生物质和生物质的热解产物代表组分（H2、CO和生物质热解液态产物）作为还原剂，锰矿和锰矿的主要代表组分（MnO2、Fe2O3和SiO2）作为被还原物，模拟研究生物质热解还原制备一氧化锰的锰矿还原率、还原温度范围和还原产物的价态变化，以及锰矿其他组分对还原过程的影响。研究表明生物质热解还原制备一氧化锰的直接还原物质主要为生物质热解产生的有机挥发分，还原过程是由生物质热解产生有机挥发分和挥发分还原氧化锰矿两个部分组成；锰矿的组分Fe2O3和SiO2具有增强生物质还原效果的作用。第三，通过对生物质热解还原制备一氧化锰的影响因素（生物质与锰矿的配比、还原温度、还原时间、生物质种类、生物质粒度、锰矿粒度、惰性气体流量以及氧气量）的研究，确定最佳还原条件；采用X射线衍射、电镜能谱和气相色谱分析方法对还原产物和尾气成分进行分析，探讨生物质热解还原氧化锰矿的反应机制；热重分析表明生物质热解还原反应可分为四个阶段：物料脱表面水阶段、物料脱结晶水阶段、主反应阶段和缓慢还原阶段；等温和不等温动力学研究表明生物质热解释放的有机挥发分和氧化锰矿的还原反应是还原反应的限速步骤，并符合一级动力学反应模型。第四，为使本方法应用于工业生产，对中试规模的工艺流程和技术方案进行设计，对各工艺单元进行探讨；对本工艺的防氧化进行系统的研究，包括产品氧化影响因素分析（氧化温度，氧化时间、生物质颗粒大小和物料堆积厚度）、氧化机制分析和防氧化措施的提出；本工艺的能量平衡、物料平衡和经济效益的计算分析，表明生物质热解还原制备一氧化锰工艺是一种有效、经济和环保的制备一氧化锰可行途径。本文围绕生物质还原氧化锰矿国家示范项目，提出高效率、低耗能和环境友好的生物质热解还原制备一氧化锰的新方法，并对还原反应的反应历程、反应影响因素、还原机理和反应动力学进行了研究；对生物质热解还原制备一氧化锰的工艺进行研究，为低品位氧化锰矿资源综合利用的工程技术开发提供了理论基础。更多还原

【Abstract】 Biomass as a widely distributed, abundant, renewable and environment-friendlyresource has been received considerable attention. The products of biomass pyrolysisare strong reductive substances as solid, liquid and gaseous. They are widely used asreductors in reduction of metal and nonmetal oxides, especially for minerals.Therefore, the biomass is used to prepare manganese monoxide by its pyrolysisprocess in stead of traditional coal. The results not only broaden the application ofbiomass, but also are a new technology for preparation of manganese monoxide withhigher efficiency and lower energy consumption. And it also can do better in improvethe mitigation of increasingly serious energy crisis, environmental and human health.Firstly, the pyrolysis process of five kinds of biomass, such as rice straw, sawdust,wheat stalk, corn stalk and bamboo powder, was investigated by thermogravimetricanalysis. The pyrolysis kinetics analysis was investigated based on thethermogravimetric data. The biomass pyrolysis components of gas, liquid, solid-statewere analyzed by gas chromatography, scanning electron microscopy and Fourierinfrared spectroscopy. The results showed that the pyrolysis process of biomass couldbe divided into four stages including evaporation of moisture, evaporation of boundmoisture, fast pyrolysis and slow pyrolysis; the biomass pyrolysis followedindependent parallel first-order reaction kinetic model; the gaseous products weremainly CO2, CO, H2, CH4, C2H4and C2H6, the solid products were mainly carbon andoxygen, while liquid products were various types of organic compounds.Secondely, the process of preparation of manganese monoxide by biomasspyrolysis was simulated by the reductors of biomass and the represents of biomasspyrolysis, such as H2, CO and biomass liquid products. The manganese oxide ore andthe main components of ore, such as MnO2、Fe2O3and SiO2, were reducted base onthe studies in the factors of reduction degree, reaction temperature and valence changeof manganese ore. The results illustrated that the biomass volatiles were the mainagents in reducing the manganese oxide ores. The reduction mechanism included twosteps that are biomass thermal degradations to releasing gaseous reductive volatilesand then reducions of the manganese oxide ore by volatiles reductors. The maincomponents of ore, such as Fe2O3and SiO2could improve the reduction efficiency ofmanganese ore by biomass pyrolysis.Thirdly, the optimum conditions of preparation of manganese monoxide bybiomass pyrolysis reduction were determined based on the investigation of influencefactors, such as biomass/manganese ore ratio, reaction temperature, reaction time, types of biomass, particle size of biomass, particle size of manganese ore, flow rate ofinert air and amount of oxygen. By the analysis of X-ray powder diffraction, scanningelectron microscopy and energy dispersive X-ray spectroscopy on the reduced sampleand GC analysis on gas composition of the outlet gas, the reduction mechanism wasspeculated. The reduction process of manganese oxide ore by biomass pyrolysis couldbe divided into four stages including evaporation of moisture, evaporation of boundmoisture, main reduction and slow reduction. Kinetic results showed that thereduction process followed the first order kinetic model and the reduction rate wascontrolled by the reaction between biomass volatiles and manganese oxide ore.Lastly, in order to promoting this method in industry, the flow process andtechnology programs were planed in mid-industrial scale. The methods ofanti-oxidation were worked out based on the investigation on the influencing factors(such as reaction temperature, reaction time, particle size of biomass and materialsthickness) and the mechanism of oxidation of manganese monoxide. The estimationof energy balance, material balance and economics were evalualed, which showedthat the preparation of manganese monoxide by biomass pyrolysis was effective,economically feasible and environment-friendly for industrially preparing manganesemonoxide.With regard to the national demonstration project on the reduction of manganeseoxide ore by the biomass pyrolysis, an efficient method of preparing manganese oxideis put forward with the advantages of lower energy consumption and the friendlyenvironment. The reduction process was studied on the reaction mechanism, influencefactors, reduction mechanism and reduction kinetics. The technology of preparingmanganese oxide of biomass pyrolysis was designed. It is a theoretical basis for thecomprehensive utilization of lower grade manganese ore resources.更多还原