MIEC催化剂设计、制备及其催化热解甘蔗渣木质素构效关系研究

发布时间：2018-03-14 01:21

  本文选题：固相法　切入点：MIEC　出处：《东北石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：木质素是生物质中除纤维素外含量第二的可再生资源,具有储量丰富、再生速度快等优点。木质素结构有丰富的官能团,如碳链、芳香环、甲氧基、羟基和羧基等,可以作为生产酚类等高附加值的精细化学品原料。在木质素热解过程中加入催化剂可以降低其选择性断键等反应活化能、提高反应速率、调节目的产物的选择性和收率。通过设计和开发具有高选择性催化剂可以选择性活化、断裂某一类化学键,选择性催化制备某一类化学品,提高其经济性,实现木质素环境友好型转化利用。通过化学方法将甘蔗渣木质素催化转化为化学品是实现其资源化和高值化利用的重要途径之一。本文采用固相法制备了一系列钙钛矿型混合离子电子导体(MIEC)CaZr1-xFexO3和LaTi1-xFex O3,通过XRD、SEM、XPS对其晶型、形貌和金属赋存价态进行表征分析。利用热重对甘蔗渣木质素热解及催化热解过程进行分析,并采用固定床反应器对CaZr0.8Fe0.2O3和La Ti0.2Fe0.8O3催化热解甘蔗渣木质素性能进行评价,利用气相色谱/质谱对甘蔗渣木质素催化热解的液相产物进行分析。研究结果如下:(1)CaZr1-xFexO3呈粒状或层状致密结构,随Fe掺杂量的增加,其特征衍射峰强度增大,且向大角度偏移,晶胞体积及晶粒尺寸减小。LaTi1-xFexO3的结构平整,晶粒大小分布均匀一,其特征峰明显,结晶度较好。升高温度可以一定程度上增加衍射峰强度。增加焙烧时间不会生成新的特征峰但可以使其晶粒生长完全。(2)通过热重对甘蔗渣木质素反应过程进行分析,甘蔗渣木质素失重主要发生在180-550°C。添加CaZr0.8Fe0.2O3和LaTi0.2Fe0.8O3可以加快甘蔗渣木质素热解反应速率,减少焦炭的生成,促进其进行催化转化。(3)在CaZr0.8Fe0.2O3作用下,甘蔗渣木质素催化热解液相产物主要有苯类、苯酚类、愈创木基类、邻苯二酚类、紫丁香基类和甲氧基芳香化合物,当甘蔗渣木质素与CaZr0.8Fe0.2O3的质量比为2:1时,各类产物其选择性分别为25.01 wt.%、35.19 wt.%、6.18wt.%、10.68 wt.%和14.21 wt.%和8.73 wt.%。(4)当甘蔗渣木质素与LaTi0.2Fe0.8O3的质量比为2:1时,甘蔗渣木质素催化热解液相产物苯类、苯酚类、愈创木基类、邻苯二酚类、紫丁香基类和甲氧基芳香化合物的选择性分别为11.93 wt.%、37.08 wt.%、14.14 wt.%、6.42 wt.%、16.55 wt.%和13.88 wt.%。(5)钙钛矿型混合离子电子导体CaZr0.8Fe0.2O3和LaTi0.2Fe0.8O3进行木质素的催化热解后对其进行循环再生,对反应后的催化剂进行评价。对比反应前后催化剂的XRD和SEM等表征发现催化剂具有较高的催化活性和结构稳定性。
[Abstract]:Lignin is only second cellulose content in biomass renewable resources, has the advantages of abundant regeneration speed. The structure of lignin rich functional groups, such as carbon chain, aromatic ring, methoxy, hydroxyl and carboxyl, phenols can be used as production of high value-added fine chemicals. The addition of catalyst in the lignin pyrolysis process can reduce the reaction activation energy selective bond breaking, improve the reaction rate, adjust the product selectivity and yield. Through the design and development of the high selectivity of the catalyst can be selectively activated with a certain type of fracture, chemical bond, selective catalytic preparation of a class of chemicals, improve its economy, realize environment friendly conversion and utilization of lignin by chemical methods. The bagasse lignin catalytic conversion for chemicals is to realize its resources and high value of one of the important ways to use the. A series of perovskite type mixed ionic and electronic conductors were prepared by solid state method (MIEC) and CaZr1-xFexO3 LaTi1-xFex O3, by XRD, SEM, XPS on the crystal structure, morphology and occurrence of metal valence were characterized by thermogravimetric analysis. The bagasse lignin pyrolysis and catalytic pyrolysis process were analyzed, and the use of fixed bed reactor CaZr0.8Fe0.2O3 Ti0.2Fe0.8O3 and La on the catalytic pyrolysis of bagasse lignin properties were evaluated by gas chromatography / mass spectrometry of bagasse lignin pyrolysis liquid products were analyzed. The results are as follows: (1) CaZr1-xFexO3 in a granular or dense layered structure, with the increase of the Fe content increases, the characteristic diffraction peak intensity. And to the large angle offset, the cell volume and the reduction of grain size structure flat.LaTi1-xFexO3, grain size distribution, the characteristic peaks, better crystallinity. The increasing temperature to a certain extent. The peak intensity and diffraction. Increase roasting time without generating a new characteristic peak but can make the grain growth completely. (2) by thermogravimetry on bagasse lignin reaction process analysis, bagasse lignin loss occurs mainly by adding CaZr0.8Fe0.2O3 and LaTi0.2Fe0.8O3 at 180-550 DEG C. to accelerate bagasse lignin pyrolysis reaction rate. To reduce the coke production, promote the catalytic conversion. (3) in the presence of CaZr0.8Fe0.2O3 bagasse lignin catalytic pyrolysis liquid products are mainly benzene, phenol, catechol and guaiacol base, lilac base and methoxy aromatic compounds, when the quality of bagasse lignin and CaZr0.8Fe0.2O3 ratio 2:1, the selectivity of each product were 25.01 wt.%, 35.19 wt.%, 6.18wt.%, 10.68 wt.% and 14.21 wt.% and 8.73 wt.%. (4) when the bagasse lignin and the quality ratio of LaTi0.2Fe0.8O3 to 2:1, sugarcane Lignin residue catalytic pyrolysis liquid products of benzene, phenol, catechol and guaiacol base, selective lilac base and methoxy aromatic compounds were 11.93 wt.%, 37.08 wt.%, 14.14 wt.%, 6.42 wt.%, 16.55 wt.% and 13.88 wt.%. (5) catalytic pyrolysis of perovskite type mixed ion conductor CaZr0.8Fe0.2O3 LaTi0.2Fe0.8O3 and lignin after the recycling of the catalysts were evaluated after reaction. The catalysts before and after the comparison of XRD and SEM. The results showed that the catalytic activity of the catalyst has high and stable structure.

【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;O636.2
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本文编号：1608979