烧结料层内自热效应与次生铁酸钙系矿物耦合促进VOCs燃烧机理及调控

How to cost-effectively reduce VOCs emission of iron ore sintering process is a new challenge for iron and steel industry at present. As there are great thermodynamic and kinetic conditions to harmlessly convert VOCs to CO2 and H2O in the iron ore sintering bed, the new thought of De-VOCs in sintering bed is proposed. The project aims to in situ efficiently promote the combustion process of VOCs to CO2 and H2O by making full use of the high temperature, oxygen potential coupled with the secondary calcium ferrite minerals in the sintering bed. The formation and combustion behaviors of VOCs in different regions and the direct combustion kinetic of VOCs in the unsteady state, multicomponent and different temperature gradient of sintering bed will be investigated. The rate-determining step of the direct combustion of VOCs in sintering bed, which will provide guidance for optimizing of sintering working conditions, will be revealed. Then the adsorption and reaction behaviors (such as reaction intermediates, pathways and activation energy), catalytic combustion kinetics of VOCs and O2 by the secondary calcium ferrite minerals will be system-depth studied. The catalytic combustion mechanism of VOCs by calcium ferrite minerals will be also disclosed in these studies, and which will guide the optimizing of the reaction behaviors of calcium ferrite minerals. Furthermore, the regulation will be proposed to reduce the VOCs emission by changing the height of sinter bed to expand the combustion zone combined with optimizing the reaction behaviors of calcium ferrite minerals to increase the combustion rate of VOCs. The results of the project will enrich the theories of De-VOCs process during sintering process. The project will also provide the indispensable theoretical guidance and technical support for developing a new process to reduce VOCs emission during iron ore sintering process.

高效低成本减少铁矿烧结工序VOCs排放是当前钢铁企业面临的新挑战。鉴于烧结料层内具备将VOCs无毒性转化为CO2、H2O的良好热、动力学条件，本项目提出“强化烧结料层内VOCs燃烧”的“系内VOCs脱除”新思路，充分利用料层内高温高氧势，耦合自生成的铁酸钙系矿物，“就地”高效促进VOCs燃烧成CO2和H2O。通过研究非稳态、多组分、多温度梯度料层内不同区域VOCs的生成和燃烧行为，以及VOCs直接燃烧反应动力学，揭示其燃烧控速环节，为优化烧结工质条件提供指导；通过研究次生铁酸钙系矿物对VOCs、O2吸附反应行为（反应中间体、路径、活化能）及其燃烧动力学的影响规律，明晰其催化VOCs燃烧机理，为优化铁酸钙系矿物反应行为提供依据；阐明联合调控料层高度以扩展燃烧区域和铁酸钙系矿物反应行为以提高燃烧速率的VOCs减排机制，完善烧结系内VOCs脱除理论，为开发新一代烧结VOCs减排工艺提供基础。

围绕烧结过程VOCs高效率、低成本、无害化减排，开展了基于铁矿烧结过程自热效应与次生铁酸钙系矿物协同促进VOCs氧化燃烧的基础研究。系统研究了固体燃料、轧钢油泥等烧结原辅料燃烧过程VOCs生成规律，明晰了烧结过程VOCs形成机理；揭示了VOCs与O2直接燃烧反应动力学及其控速环节，明晰了CO、H2O、CO2等组分对VOCs直接燃烧的影响规律；查明了烧结常见铁酸钙系矿物的氧物种类型及其反应活性，揭示了铁酸钙系矿物对VOCs的吸附反应行为和催化VOCs氧化燃烧规律，明确了铁酸钙系矿物催化VOCs氧化燃烧机理；揭示了扩展高温区域以延长VOCs氧化反应时间与优化铁酸钙系矿物生成行为以催化VOCs燃烧的烧结过程VOCs减排机制，补充和完善了促进烧结过程VOCs氧化燃烧成无害化CO2和H2O的基础理论。. 在理论研究基础上，查明了料层高度对烧结过程VOCs氧化燃烧行为的影响规律，明确了扩展高温区域以延长反应时间的烧结VOCs减排方向；查明了优化石灰石粒度对烧结过程VOCs氧化燃烧的影响规律，明晰了优化铁酸钙系矿物生成行以催化VOCs氧化燃烧的烧结过程VOCs减排方向，最终形成联合调控扩展高温区域和优化铁酸钙系矿物生成行为的烧结VOCs减排工艺。在该工艺下烧结VOCs排放的最大体积浓度、平均体积浓度、吨烧结矿VOCs排放量分别降低约76.0%、77.2%、68.6%，实现烧结过程VOCs高效率、低成本、无害化减排。. 开发的基于料层内自热效应与次生铁酸钙促进VOCs燃烧的烧结过程VOCs减排工艺，已在方大特钢科技股份有限公司、九江萍钢钢铁有限公司等钢铁企业进行了探索性实践应用，取得较好的VOCs减排效果，可为烧结烟气超低排放与钢铁工业的绿色低碳发展提供技术支撑，相关研究成果发表学术论文10篇（SCI检索6篇，EI检索1篇）。项目执行期间，项目负责人由助理研究员晋升为副研究员，并入选江西省科学院杰出青年。

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