Ni-W-B非晶态催化剂的制备及其对生物油加氢脱氧性能研究

发布时间：2018-01-16 01:11

本文关键词：Ni-W-B非晶态催化剂的制备及其对生物油加氢脱氧性能研究　出处：《湘潭大学》2015年硕士论文　论文类型：学位论文

【摘要】：传统能源煤、石油等对环境造成较大的污染,导致生态破坏,严重制约了我国经济的快速发展,开发新型可再生绿色环保型资源迫在眉睫。生物油是指在隔绝氧气、高温(773~873 K)的条件下先将生物质(木材、秸秆等)颗粒物迅速加热使其裂解,再迅速冷凝而得到的液体燃料。生物油因其原料来源广泛、便于运输、可再生、能量密度较高等特点备受关注。但由于其自身含氧量较高,致使生物油具有热稳定性差、易腐蚀、燃烧热值低、不互溶、黏度高等缺点,严重影响了生物油的广泛应用。因此,我们必须对生物油进行加氢脱氧提质改性,使其更好的得到应用,开发出高效、节能的加氢脱氧催化剂,对生物油催化加氢脱氧制备新型石油替代能源具有重要意义。因酚类化合物中的氧与苯环直接相连,断裂该C-O键需要的活化能最大,被认为是生物油中最难脱氧的一类化合物。一般来讲,酚类化合物的加氢脱氧反应路径包括直接脱氧和加氢—脱氧,其中直接脱氧需要的反应温度较高,加氢—脱氧路径可以显著降低反应温度,其关键是准备高加氢活性催化剂。非晶态合金催化材料具有长程无序、短程有序的独特结构,在加氢反应中表现出优良催化活性。因此,本文先采用化学还原法制备非晶态Ce-Ni-W-B催化剂,主要研究助剂Ce对催化剂HDO性能的影响。结果显示,添加助剂Ce增加催化剂表面Ni0和WO3的含量,在催化对甲基苯酚的HDO反应中显示出较高的催化活性,催化剂的HDO活性主要取决于催化剂表面Ni0的相对含量及Ni0与WO3的摩尔比。适量助剂Ce的加入有利于提高Ni-W-B非晶态催化剂催化对甲苯酚的HDO转化率和脱氧率。当Ce3+/W6+摩尔比为25时,对甲基苯酚的脱氧率达98.1%。在此基础上,改变制备方法,在制备过程中加入氨水调节母液的pH值,调控金属离子与硼氢化钠的反应速率,制备出非晶态Ni-W-B催化剂,主要研究不同Ni-W摩尔比对催化剂加氢脱氧性能的影响。改变原料液中Ni-W摩尔比可以调控催化剂中Ni0与WO3的相对含量,从而调控对甲基苯酚HDO反应产物的分布。当Ni-W摩尔比为1:3时,催化的HDO活性最高,在498 K下反应4h后,催化对甲基苯酚的脱氧率达到88.4%。
[Abstract]:Traditional energy sources, such as coal, oil and other environmental pollution, leading to ecological destruction, seriously restricted the rapid development of China's economy. It is urgent to develop new renewable green and environment-friendly resources. Biooil refers to biomass (wood) under the condition of oxygen isolation and high temperature of 773N 873K. Liquid fuel obtained by rapid heating and condensation of particulate matter. Biooil is easy to transport and renewable because of its wide source of raw materials. However, because of its high oxygen content, bio-oil has the disadvantages of poor thermal stability, easy corrosion, low combustion calorific value, insoluble, high viscosity and so on. The application of bio-oil has been seriously affected. Therefore, we must improve the hydrodeoxidization of bio-oil so that it can be better used to develop high-efficiency and energy-saving hydrogenation deoxidation catalyst. Because the oxygen in phenolic compounds is directly linked to benzene ring, the activation energy required for breaking the C-O bond is the largest. Generally speaking, the hydrodeoxidation pathways of phenolic compounds include direct deoxidation and hydrogen-deoxidation, in which direct deoxidation requires a higher reaction temperature. The hydrogenation and deoxidation pathway can significantly reduce the reaction temperature, and the key point is to prepare high hydrogenation active catalyst. Amorphous alloy catalyst materials have the unique structure of long range disorder and short range order. Therefore, the amorphous Ce-Ni-W-B catalyst was prepared by chemical reduction method. The effect of ce on the HDO performance of the catalyst was studied. The results showed that the addition of ce increased the content of Ni0 and WO3 on the catalyst surface. In the HDO reaction of p-methylphenol, the catalytic activity was higher. The HDO activity of the catalyst mainly depends on the relative content of Ni0 on the surface of the catalyst and the molar ratio of Ni0 to WO3. HDO conversion and deoxidation of phenol. When Ce3. When the mole ratio of / W _ 6 is 25. The deoxidization rate of p-methylphenol reached 98.1. On this basis, the preparation method was changed, ammonia solution was added to adjust the pH value of the mother liquor, and the reaction rate between metal ions and sodium borohydride was regulated. Amorphous Ni-W-B catalyst was prepared. The effect of different molar ratio of Ni-W on the hydrodeoxidation performance of the catalyst was studied. The relative content of Ni0 and WO3 in the catalyst could be controlled by changing the molar ratio of Ni-W in the feedstock solution. When the molar ratio of Ni-W is 1: 3, the catalytic activity of HDO is the highest, and after 4 h reaction at 498K. The catalytic deoxidation rate of p-methylphenol reached 88.4%.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ426.6;TE667

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