【作者】 刘建军；

【导师】 李建芬；

【作者基本信息】 武汉工业学院 ， 生物化工， 2011， 硕士

【摘要】 随着社会经济的发展和城市化进程的加快,城市生活垃圾的增长速度及其数量也在不断的加快。传统的生活垃圾处理技术主要包括填埋、堆肥、焚烧等,但这些方法都存在一定的弊端和二次污染问题。而垃圾气化处理技术,由于具有污染物排放低、显著的减量减容性以及产生可燃气体等优点,被认为是焚烧处理最具有潜力的替代技术,逐渐成为新的研究热点。本文采用均匀沉淀法制备镍铁氧体复合晶体,探讨了反应物配比、反应温度和时间、煅烧温度等因素对制备工艺的影响,确定复合晶体制备的最佳工艺条件;采用XRD、FTIR、SEM等表征手段对复合晶体进行分析表征。分析结果表明,所得产品为NiFe₂O₄、NiO复合纳米晶体,结晶完整,粒度均匀,属立方晶系尖晶石结构,平均粒径约为52nm。同时,探讨了沉淀和煅烧反应过程中各因素对产品产率及平均粒径的影响,实验得出制备复合晶体的最佳工艺条件为:反应物镍铁盐比例n（Ni）/n（Fe）为3:1,沉淀反应温度和时间分别为110℃和2.0h,煅烧温度600℃。采用沉积沉淀法制备Ni-Fe/γ-Al₂O₃,Ni-Co/γ-Al₂O₃,Ni-Ce/γ-Al₂O₃等3种镍基催化剂,采用XRD、FTIR、SEM等表征手段对催化剂进行分析表征,并将催化剂用于城市生活垃圾催化气化产品气中焦油的裂解和重整,对催化剂的催化性能进行测试和比较。在固定床反应装置上,采用自制的镍基催化剂,对城市生活垃圾裂解气化进行研究,探讨了催化剂、气化炉温度、水蒸气物料比（S/M）、原料粒径等因素对产气特性的影响,对生成气体的产率和成分进行分析,确定催化气化的最佳工艺条件。实验结果表明,生活垃圾催化气化所得产品气的主要成分为H₂、CO、CH₄和CO₂等,镍基催化剂能有效促进焦油的裂解、改善气体的品质,自制的3种镍基催化剂的催化效果为:Ni-Fe/γ-Al₂O₃﹥Ni-Ce/γ-Al₂O₃﹥Ni-Co/γ-Al₂O₃,其中Ni-Fe/γ-Al₂O₃催化剂在800℃时焦油的去除率达到99%,H₂产率最高可达到56%;温度是影响气体产率和品质的重要因素,温度越高,H₂含量和气体产率越高;水蒸气的引入能提高气体品质和产率,但是过多的水蒸气会降低气化温度,从而降低气体的品质,实验条件下水蒸气物料比（S/M）最佳比值是1.33;原料粒径同样是影响气体产率和组分的重要因素,粒径越小,产品气的品质和H₂含量越高。同时,对城市生活垃圾催化裂解和气化、水蒸气重整制取富氢燃气的反应机理进行了初步分析和研究。更多还原

【Abstract】 As the social and economic development and urbanization process acceleration, the generation rate and the production of municipal solid waste （MSW） increased rapidly. Traditional disposal processing of municipal solid waste, including landfill, composting, incineration, have drawbacks and secondary pollution. The gasification technology, because of its low emissions, a significant reduction of the capacity and the production of combustible gases, is considered to be the most potential alternative technologies for incineration, and gradually become a new hotspot.Nickel ferrite nanocomposites were prepared by a homogeneous precipitation method and the influences of various processing parameters in preparation process on the yield and mean size of the product were also investigated. Meanwhile, XRD, FTIR and SEM were used to characterize the nanoparticles and precursors. The results indicated that the production prepared at the optimum conditions were NiFe2O4 and NiO nanocomposites, they were uniform in particle size and had a fine crystal phase of cubic spinel structure with a mean size of 52 nm. The optimum conditions for preparing nanocrystalline were as follows: the molar ratio of nickel chloride hexahydrate to iron nitrate nonahydrate was 3:1, the temperature of precipitation reaction was 110℃, the reaction time was 2.0 h, and the calcination temperature was 600℃.The nickel-based catalysts such as Ni-Fe/γ-Al₂O₃, Ni-Co/γ-Al₂O₃, Ni-Ce/γ-Al₂O₃ were prepared by deposition-precipitation （DP） method, and XRD, FTIR and SEM were used to characterize the catalysts. For the purpose of testing and comparing the performance of the catalysts, the catalysts were used to pyrolyze and reforming tar in the product gas which is produced from catalytic gasification of municipal solid waste. The catalytic cracking and gasification experiments were carried out in a fixed bed reactor with municipal solid waste as raw material and using self-made nickel-based catalyst. The effects of catalyst, reactor temperature, steam to municipal solid waste ratio （S/M）, particle size of municipal solid waste that influence the characteristics of gas production were discussed, and the yield and composition of the product gas were analyzed to determine the best catalytic gasification process conditions. The experimental results showed that the main component of product gas from MSW gasification were H₂, CO, CH₄ and CO₂, and the nickel-based catalyst could effectively promote tar cracking, improve the gas quality. The catalytic properties of the three kinds of nickel-based catalysts were: Ni-Fe/γ-Al₂O₃ > Ni-Ce/γ-Al₂O₃ > Ni-Co/γ-Al₂O₃, of which Ni-Fe/γ-Al₂O₃ catalyst could reach 99% tar removal rate at 800℃, and the maximum yield of H₂ 56%. The parametric tests indicated that temperature was the most important factor in this process, and higher temperature favored hydrogen production and gas yield. This experimental test has also confirmed that the introduction of steam to MSW gasification was favorable for improving gas quality and hydrogen yield. However, excessive steam would lower gasification temperature and so degrade product gas quality. Focusing on gas yield and quality as well as energy aspects, the optimal value of S/M was found to be 1.33 under the present operating condition. MSW particle size also had influence on gas composition and gas yield; the smaller particles were more favorable for gas quality and H2 yield. Meanwhile, catalytic cracking and gasification of MSW, steam reforming of hydrocarbons were discussed preliminarily, to explore the reaction mechanism of catalytic gasification of municipal solid waste to produce hydrogen-rich gas.更多还原