La、Ce改性氧化鋁載體對氧化脫硫反應(yīng)的影響
發(fā)布時間：2019-03-20 13:10
【摘要】：國五汽油標(biāo)準(zhǔn)在2013年12月18日出臺并立即實(shí)施,此標(biāo)準(zhǔn)借鑒了其他地區(qū)或國家的汽油標(biāo)準(zhǔn),同時也聽取了社會各界的意見,從而保證了可行性與專業(yè)性。在該標(biāo)準(zhǔn)下,車用油中的硫含量將由原來的50 ppm降低至10 ppm,這樣的改動顯示了政府部門對油品中硫含量的重視。近些年來備受關(guān)注的霧霾問題,汽車尾氣中的含硫化合物便是罪魁之一。除此之外,含硫化合物還會引起酸雨,煙霧等環(huán)境問題,同時也會引起嚴(yán)重的健康問題,影響呼吸系統(tǒng)的正常運(yùn)作。這一系列的問題都提醒了我們,油品的脫硫,或者說,深度脫硫,已經(jīng)成為了當(dāng)前不得不解決的問題。而傳統(tǒng)的加氫脫硫工藝在噻吩類含硫化合物的脫除上存在嚴(yán)重不足,且工藝本身成本過高,條件苛刻。相比之下,氧化脫硫做為一種新型的脫硫方法,很好的填補(bǔ)了加氫脫硫的不足。本文主要從氧化脫硫催化劑的載體入手,對催化劑進(jìn)行改性,探討改性催化劑對DBT的氧化脫硫性能,并在此基礎(chǔ)上,使用環(huán)己烯氧化反應(yīng)驗(yàn)證改性載體對于其他氧化反應(yīng)也存在優(yōu)秀的催化效果。本文首先分別通過等體積浸漬法制備了γ-Al2O3、La-A12O3、Ce-A12O3(四種)負(fù)載的幾種鉬基催化劑,使用這些催化劑分別在TBHP和CHP的氧化下進(jìn)行了DBT的氧化脫硫反應(yīng)。結(jié)果發(fā)現(xiàn),La和Ce的改性均提升了催化劑的氧化脫硫活性,其中,Ce含量2.15%的載體制備的催化劑性能最優(yōu),且TBHP是更適合反應(yīng)的氧化劑。隨后對催化劑進(jìn)行表征,結(jié)果認(rèn)為,La和Ce的改性均提升了催化劑表面的氧化鉬物種,八面體鉬物種的含量增加的尤為明顯。在第二部分的實(shí)驗(yàn)中,將活性組分由鉬基換成鎢基進(jìn)行DBT的氧化硫反應(yīng),結(jié)果表明,La和Ce的改性對于鎢基催化劑依然有效,但鎢基催化劑的整體活性及穩(wěn)定性較鉬基催化劑存在不小的差距。環(huán)己烯的氧化產(chǎn)物做為重要的化工原料,有著廣泛的應(yīng)用。因此在本文的最后,以CHP為氧化劑,使用改性前后的催化劑在釜式反應(yīng)器中進(jìn)行環(huán)己烯氧化反應(yīng),用以拓展催化劑的適用范圍。實(shí)驗(yàn)的結(jié)果驗(yàn)證了La與Ce的改性不僅僅適用于氧化脫硫反應(yīng),同樣可以催化環(huán)己烯氧化反應(yīng)。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, 緯-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.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：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, 緯-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.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：O643.36
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