【作者】 宋磊；

【导师】 彭书传；

【作者基本信息】 合肥工业大学 ， 环境工程， 2009， 硕士

【摘要】 生物质热解气化技术的发展与广泛应用,使生物质热解焦油的影响越来越为人们所关注。在前人对凹凸棒石(PG)性质和结构的研究基础上,本文以凹凸棒石为催化剂,并且负载活性组分Ni以提高其催化性能,以生物质焦油的重要组成成分二甲苯为模拟化合物,对二甲苯的催化裂解(水汽重整)反应进行了深入的实验研究。在分析了该领域研究现状的基础上,建立了实验室规模的气固相连续催化裂解反应器,用气相色谱连续在线分析催化裂解产生的气体成分和含量。以等体积浸渍法对提纯改性后的凹凸棒石粘土进行活性组分(NiO)负载,经过干燥、煅烧后制备出不同Ni担载量的Ni/PG催化剂。采用XRD、TEM、BET等手段检测和表征了催化剂的结构特性和组分特性,并进行了理论分析。通过活性评价优化了催化剂的主要制备参数(Ni负载量、煅烧温度等)和操作条件(反应温度、空速、水汽含量)并分析了二甲苯转化率的主要影响因素;考察了催化剂活性随反应时间的变化规律,得出了可能导致催化剂失活的主要原因是表面积碳和催化剂结构破坏。通过对裂解气组分的在线分析,研究了催化剂选择性的影响因素。初步提出了二甲苯在凹凸棒石负载Ni催化剂上水汽重整裂解反应的机理,发现了水汽的存在是消除催化剂积碳的有效因素,同时也阐明了催化剂活性对凹凸棒石特性结构的依赖性。本课题的研究表明,凹凸棒石负载金属Ni催化剂具有较好的催化脱除以芳香烃为主的生物质气化焦油性能,为开发出可适用于工业化的生物质气化系统的焦油催化转化技术提供了技术参数和理论支持。更多还原

【Abstract】 As an increasing development and wide application of the technology of biomass pyrolysis and gasification, the impact of biomass pyrolysis tar is paid more and more attention. In this paper, based on the previous research on the nature and structure of palygorskite(PG), xylene catalytic cracking (steam reforming) reaction is carried out in-depth experimental study taking palygorskite as catalyst and xylene as model compound of biomass.On the analysis of the previous research on this topic, a gas-solid reactor for catalytic cracking is established in laboratory-scale, and gas chromatography is used to analyze the composition and content of the gases produced in catalytic cracking reaction. Volume impregnation method is implemented in the active component (NiO) load of the purified palygorskite. The loaded palygorskite is dried and calcined to get Ni/PG catalyst with different amount of Ni-supported. XRD, TEM, BET and other means are used to detect and characterize the structural characteristics and properties of the catalyst. Through the evaluation of the activity of the catalyst, the major preparation parameters (Ni loading, calcination temperature, etc.) and operating conditions (reaction temperature, space velocity, water vapor content) are optimized and the main factors of the rate of xylene are also analyzed. The rule of catalyst activity with the changes of reaction time is reviewed, and it is concluded that the possible cause of catalyst deactivation generally is carbon deposition and the damage of catalyst surface structure. Through the online analysis on cracked gas components, the selective factor of catalyst is researched. It is attempted to put forward the mechanism of steam reforming reaction processing xylene and palygorskite loaded Ni. It is not only observed that the presence of water vapor is an effective factor to eliminate carbon deposition of catalyst, but also found that the activity of catalyst is dependent on the structure of palygorskite. In conclusion, this paper shows that the palygorskite loaded Ni is an good catalyst to remove biomass gasification tar mainly composed of aromatics. This paper also provide technical parameters and theoretical support for the industrialization of catalytic technology in the conversion of tar.更多还原