天然针铁矿负载镍催化裂解焦油性能和机理

Biomass gasification offers the potential for producing a fuel gas that can be used for power generation systems or synthesis gas applications. However, it is inevitably accompanied by the formation of biomass tar, which not only affects the normal running of biomass gasification systems but also decrease the utilization efficiency of biomass. Therefore, it is an urgent problem how to purify biomass gasification gases using low-cost natural nano-mineral materials. The previous study done by applicant showed palygorskite-supported Ni and Fe had a synergetic reactivity on catalytic cracking of biomass tar. Based on the properties of nano acicular crystal state of natural goethite, lattice defects with rich-Al-substitution, and high surface chemistry activity, the project proposes to prepare nano-composite by supporting Ni on natural nano goethite. Characterization techniques such as HRTEM, in situ heating XRD, Special Surface Area analyzer, Mass Spectrum, etc and catalytic reaction equipment will be used during the process. The aims are to (1) investigate the effect of Al-substitution on crystal structure and physico-chemical properties of goethite-supported Ni and the relationship between Al-substitution and catalytic reactivity, (2) investigate the factors affecting the reactivity of nano composite of goethite-supported Ni on catalytic cracking of biomass tar, and (3) research the mechanism of catalytic cracking of tar over goethite-supported Ni and the way how to recycle catalysts. The performance will provide a new and low-cost material for the utilization of biomass resources, and improve the research of crystal chemistry and mineral physics of goethite. The project makes considerable significance in the research of mineral materials and environmental mineralogy.

热解气化是重要的生物质可再生能源利用途径，然而，生物质热解气中微量焦油严重影响气化系统正常工作，如何利用廉价的天然纳米矿物材料净化生物质热解气中焦油，是迫切需要研究解决的重要科学问题。申请人前期研究发现载体上同时负载铁镍活性组分具有协同催化裂解焦油活性。本项目基于天然针铁矿具有纳米针状晶体形态、富铝替位晶格缺陷以及热化学和表面化学活性高的特点，提出在天然纳米针铁矿上负载镍制备铁镍纳米复合材料，并借助高分辨电镜、X射线衍射仪、比表面分析仪、在线小型质谱仪、气固相催化反应器等仪器设备手段，着重研究针铁矿中铝对催化剂结构和物理化学性质演化影响，及其与催化裂解焦油活性的关系；查明影响该铁镍复合材料催化裂解焦油性能的因素；探讨该材料催化焦油裂解作用机理以及该催化剂回收和再生方法。成果将为生物质能源化利用提供先进矿物材料，推动针铁矿晶体化学与矿物物理研究；对纳米矿物材料、环境矿物学研究具有重要意义。

对铜陵地区褐铁矿资源进行了深入调查，对采集样品及不同温度热处理样品系统的XRD、XRF、FE-SEM、TEM、AAS、ICP-MS、IR、TG、BET-N2分析，查明了褐铁矿矿物组成、主量与微量元素组成，针铁矿矿物成分、形貌与微结构特征，阐明了铜陵地区褐铁矿的纳米矿物学特征，建立了硫化物风化型、菱铁矿风化型、矽卡岩矿物风化型三种成因类型及其识别标志；揭示了针铁矿表面化学性质及其热分解纳米化过程和结构演变规律，指明褐铁矿中针铁矿属于纳米矿物，褐铁矿属于纳米矿物资源，叶山褐铁矿属于天然铁锰纳米复合材料；发明了系列通过矿物热分解相变实现纳米化的新材料制备和应用方法。.建立达到国际水平的矿物催化裂解焦油评价平台。以铜陵新桥褐铁矿为原料经过煅烧得到高比表面、高活性的赤铁矿，对其催化裂解焦油模拟化合物甲苯的性能进行了系统研究。.考察了反应温度、空速比对催化裂解甲苯性能的影响，同时在最佳反应条件下对催化剂催化裂解甲苯进行了寿命评价，探索了催化剂的再生性能。研究结果表明在700℃及小于5662 h-1的条件下甲苯去除率可达到90%以上；在600min中的寿命评价中甲苯去除率仍然可以维持在80%以上；催化剂进行多次再生，甲苯去除率都在90%左右。催化反应过程中赤铁矿转变成为磁铁矿，可以磁选回收。空气中煅烧去除表面积碳又转变为赤铁矿，实质是对催化剂中活性晶格氧的利用及再生。为开发利用这种廉价、丰富、环境友好型的纳米矿物资源提供了新思路。.本项目已经在国际SCI刊物发表论文16篇，在国内中文核心刊物发表学术论文9篇，申请发明专利10项，已获得授权发明专利4项，培养硕博研究生10名。参加国际学术会议6人次，带领课题组成员及研究生参加了各类全国性学术交流会议50余人次。