【摘要】：本文針對(duì)合成氣制備低碳烯烴中催化劑的制備關(guān)鍵技術(shù)問(wèn)題,以堇青石為載體,鐵基催化劑為主體,通過(guò)分析不同金屬鉬、鎳的添加對(duì)催化劑性能的影響,研究了不同催化劑的物相、形貌、電子結(jié)合能等特征,以及制備催化劑過(guò)程中不同物質(zhì)之間的質(zhì)量比、載體堇青石的鋁溶膠改性、助劑的添加量對(duì)催化劑性能的影響等。通過(guò)對(duì)反應(yīng)因素,溫度、合成氣比例、空速進(jìn)行探討以獲得最佳的催化活性。結(jié)果表明:(1)以堇青石為載體,鐵和鉬為主要原料制備的催化劑,具有分散活性組分的作用。SEM、EDX、FTIR、以及XPS等分析發(fā)現(xiàn)起活性作用的鐵和鉬分別以四氧化三鐵和氧化鉬的形式存在。該催化劑最佳的活性條件為:反應(yīng)溫度為450℃C、合成氣比例為2、空速為2.0L/g cat-h,乙烯的選擇性和原料氣一氧化碳的轉(zhuǎn)化率達(dá)到最大為53.8%和63.5%。(2)通過(guò)添加鉀助劑對(duì)催化劑的電子結(jié)構(gòu)以及通過(guò)鋁溶膠對(duì)堇青石進(jìn)行改進(jìn)后,同樣具有較好的催化效果。SEM、TEM、EDX、XRD、XPS等分析表明鋁溶膠的改性增大催化劑的表面積,有利于活性組分的分散。鉀助劑的添加更有利于鐵物質(zhì)以低價(jià)活性態(tài)形式存在。(3)當(dāng)鐵和鉬的合成比例為1:1,鉀助劑的含量為0.12wt%,鋁溶膠改性堇青石等催化效果更佳。當(dāng)反應(yīng)溫度為450℃C,合成氣比例為1,空速為1200 mL/g cat-h的情況,一氧化碳的轉(zhuǎn)化率最高為51.4%,乙烯的選擇性也最大為25.2%。(4)鐵基催化劑和鎳基催化劑構(gòu)成的雙金屬催化因堇青石的活性分散作用,對(duì)C2烴的選擇性以及一氧化碳的轉(zhuǎn)化率具有高效的活性。當(dāng)反應(yīng)溫度為450℃C,合成氣比例為2,空速為2800mL/gcat-h,其中C2烴的選擇性最大為37.7%,乙烯的選擇性為26.6%,一氧化碳的轉(zhuǎn)化率為58.5%。
[Abstract]:In view of the key technical problems in the preparation of catalysts for the preparation of low olefins from syngas, cordierite was used as the carrier and iron based catalysts as the main body. The effects of the addition of different metal molybdenum and nickel on the performance of the catalysts were analyzed. The phase, morphology, electronic binding energy of different catalysts, the mass ratio of different materials in the preparation of the catalyst, the modification of cordierite supported by aluminum sol, and the effect of additives on the performance of the catalyst were studied. The optimum catalytic activity was obtained by discussing the reaction factors, temperature, syngas ratio and space velocity. The results showed that: (1) the catalysts prepared with cordierite as the carrier and iron and molybdenum as the main raw materials had the effect of dispersing the active components. The results of FTIR and XPS analysis showed that the active iron and molybdenum existed in the form of Fe _ 2O _ 3 and Mo _ 2O _ 3, respectively. The optimum conditions are as follows: the reaction temperature is 450 鈩，

本文編號(hào)：2130591