La、Ce改性氧化铝载体对氧化脱硫反应的影响
发布时间：2019-03-20 13:10
【摘要】：国五汽油标准在2013年12月18日出台并立即实施,此标准借鉴了其他地区或国家的汽油标准,同时也听取了社会各界的意见,从而保证了可行性与专业性。在该标准下,车用油中的硫含量将由原来的50 ppm降低至10 ppm,这样的改动显示了政府部门对油品中硫含量的重视。近些年来备受关注的雾霾问题,汽车尾气中的含硫化合物便是罪魁之一。除此之外,含硫化合物还会引起酸雨,烟雾等环境问题,同时也会引起严重的健康问题,影响呼吸系统的正常运作。这一系列的问题都提醒了我们,油品的脱硫,或者说,深度脱硫,已经成为了当前不得不解决的问题。而传统的加氢脱硫工艺在噻吩类含硫化合物的脱除上存在严重不足,且工艺本身成本过高,条件苛刻。相比之下,氧化脱硫做为一种新型的脱硫方法,很好的填补了加氢脱硫的不足。本文主要从氧化脱硫催化剂的载体入手,对催化剂进行改性,探讨改性催化剂对DBT的氧化脱硫性能,并在此基础上,使用环己烯氧化反应验证改性载体对于其他氧化反应也存在优秀的催化效果。本文首先分别通过等体积浸渍法制备了γ-Al2O3、La-A12O3、Ce-A12O3(四种)负载的几种钼基催化剂,使用这些催化剂分别在TBHP和CHP的氧化下进行了DBT的氧化脱硫反应。结果发现,La和Ce的改性均提升了催化剂的氧化脱硫活性,其中,Ce含量2.15%的载体制备的催化剂性能最优,且TBHP是更适合反应的氧化剂。随后对催化剂进行表征,结果认为,La和Ce的改性均提升了催化剂表面的氧化钼物种,八面体钼物种的含量增加的尤为明显。在第二部分的实验中,将活性组分由钼基换成钨基进行DBT的氧化硫反应,结果表明,La和Ce的改性对于钨基催化剂依然有效,但钨基催化剂的整体活性及稳定性较钼基催化剂存在不小的差距。环己烯的氧化产物做为重要的化工原料,有着广泛的应用。因此在本文的最后,以CHP为氧化剂,使用改性前后的催化剂在釜式反应器中进行环己烯氧化反应,用以拓展催化剂的适用范围。实验的结果验证了La与Ce的改性不仅仅适用于氧化脱硫反应,同样可以催化环己烯氧化反应。且Ce的改性效果更好。
[Abstract]:The national five-year gasoline standard was issued and implemented immediately on December 18, 2013. This standard draws lessons from the gasoline standards of other regions or countries, and also listens to the opinions of all sectors of the society, thus ensuring the feasibility and professionalism. Under this standard, the change of sulfur content in vehicle oil from 50 ppm to 10 ppm, shows that the government attaches importance to sulfur content in oil products. Sulfur compounds in automobile exhaust are one of the most concerned haze problems in recent years. In addition, sulfur compounds also cause acid rain, smoke and other environmental problems, but also cause serious health problems, affecting the normal functioning of the respiratory system. This series of problems remind us that oil desulfurization, or deep desulfurization, has become a problem that has to be solved. However, the traditional hydrodesulfurization process has serious deficiencies in the removal of thiophene sulfur compounds, and the cost of the process itself is too high and the conditions are harsh. In contrast, oxidation desulfurization, as a new desulfurization method, is a good way to fill the shortcomings of hydrodesulfurization. In this paper, starting with the support of oxidation desulfurization catalyst, the catalyst was modified, and the oxidation desulfurization performance of the modified catalyst to DBT was discussed, and on the basis of this, the oxidation desulfurization performance of the modified catalyst was discussed. Cyclohexene oxidation reaction was used to verify the excellent catalytic effect of the modified carrier on other oxidation reactions. In this paper, 纬-Al2O3,La-A12O3,Ce-A12O3 (four kinds) supported molybdenum-based catalysts were prepared by the equal volume impregnation method, respectively. The oxidative desulfurization of DBT was carried out with these catalysts under the oxidation of TBHP and CHP, respectively. The results showed that both the modification of La and Ce enhanced the oxidative desulfurization activity of the catalyst. Among them, the catalyst with 2.15% Ce content had the best performance, and TBHP was the more suitable oxidant for the reaction. The results showed that both the modification of La and Ce increased the molybdenum oxide species on the catalyst surface, especially the octahedral molybdenum species. In the second part of the experiment, the active component was changed from molybdenum group to tungsten group for sulfur oxidation of DBT. The results showed that the modification of La and Ce was still effective for tungsten-based catalyst. However, the overall activity and stability of tungsten-based catalysts are much lower than those of molybdenum-based catalysts. As an important chemical raw material, the oxidation products of cyclohexene have been widely used. At the end of this paper, CHP was used as oxidant and the modified catalyst was used to oxidize cyclohexene in a tank reactor in order to expand the application of the catalyst. The results show that the modification of La and Ce is not only suitable for oxidative desulfurization, but also can catalyze the oxidation of cyclohexene. And the modification effect of Ce is better.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36
[Abstract]:The national five-year gasoline standard was issued and implemented immediately on December 18, 2013. This standard draws lessons from the gasoline standards of other regions or countries, and also listens to the opinions of all sectors of the society, thus ensuring the feasibility and professionalism. Under this standard, the change of sulfur content in vehicle oil from 50 ppm to 10 ppm, shows that the government attaches importance to sulfur content in oil products. Sulfur compounds in automobile exhaust are one of the most concerned haze problems in recent years. In addition, sulfur compounds also cause acid rain, smoke and other environmental problems, but also cause serious health problems, affecting the normal functioning of the respiratory system. This series of problems remind us that oil desulfurization, or deep desulfurization, has become a problem that has to be solved. However, the traditional hydrodesulfurization process has serious deficiencies in the removal of thiophene sulfur compounds, and the cost of the process itself is too high and the conditions are harsh. In contrast, oxidation desulfurization, as a new desulfurization method, is a good way to fill the shortcomings of hydrodesulfurization. In this paper, starting with the support of oxidation desulfurization catalyst, the catalyst was modified, and the oxidation desulfurization performance of the modified catalyst to DBT was discussed, and on the basis of this, the oxidation desulfurization performance of the modified catalyst was discussed. Cyclohexene oxidation reaction was used to verify the excellent catalytic effect of the modified carrier on other oxidation reactions. In this paper, 纬-Al2O3,La-A12O3,Ce-A12O3 (four kinds) supported molybdenum-based catalysts were prepared by the equal volume impregnation method, respectively. The oxidative desulfurization of DBT was carried out with these catalysts under the oxidation of TBHP and CHP, respectively. The results showed that both the modification of La and Ce enhanced the oxidative desulfurization activity of the catalyst. Among them, the catalyst with 2.15% Ce content had the best performance, and TBHP was the more suitable oxidant for the reaction. The results showed that both the modification of La and Ce increased the molybdenum oxide species on the catalyst surface, especially the octahedral molybdenum species. In the second part of the experiment, the active component was changed from molybdenum group to tungsten group for sulfur oxidation of DBT. The results showed that the modification of La and Ce was still effective for tungsten-based catalyst. However, the overall activity and stability of tungsten-based catalysts are much lower than those of molybdenum-based catalysts. As an important chemical raw material, the oxidation products of cyclohexene have been widely used. At the end of this paper, CHP was used as oxidant and the modified catalyst was used to oxidize cyclohexene in a tank reactor in order to expand the application of the catalyst. The results show that the modification of La and Ce is not only suitable for oxidative desulfurization, but also can catalyze the oxidation of cyclohexene. And the modification effect of Ce is better.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36
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