本文選題：納米固體堿　切入點(diǎn)：催化　出處：《西安石油大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：本文通過浸漬法和共混法制備KF/γ-Al_2O_3催化劑,以其作為催化劑,考察其在催化油脂-碳酸二甲酯-甲醇連續(xù)雙酯交換體系制備生物柴油中的催化性能。結(jié)果表明,共混法制備的納米催化劑KF/γ-Al_2O_3具有更高的催化活性。在油/酯/醇摩爾比為1/1/8,催化劑用量5%,反應(yīng)時(shí)間30min,生物柴油產(chǎn)率可達(dá)98.82%,比相同反應(yīng)條件下浸漬法制備的KF/γ-Al_2O_3催化效果提高40%。與傳統(tǒng)甲醇-油脂酯交換制備生物柴油體系相比,該體系達(dá)到98%生物柴油產(chǎn)率所需時(shí)間縮短近40min。采用TGA、BET、CO_2-TPD和IR對(duì)催化劑進(jìn)行表征,結(jié)果表明KF/γ-Al_2O_3催化劑具有高活性的主要原因是焙燒過程中得到新的強(qiáng)堿性位點(diǎn)K2O,極大地提高了催化劑的堿性強(qiáng)度。實(shí)驗(yàn)還通過溶膠-凝膠法制備了一系列納米堿金屬氧化物催化劑,分別考察該類固體堿在催化油脂-碳酸二甲酯-甲醇連續(xù)雙酯交換反應(yīng)體系制備生物柴油中的反應(yīng)性能。結(jié)果表明,納米級(jí)別氧化物催化效果明顯優(yōu)于普通固體堿,其中,納米CaO表現(xiàn)出良好的催化活性。在油/酯/醇摩爾比1/1/8,催化劑用量5%,反應(yīng)4h生物柴油產(chǎn)率最高為92.82%,比普通氧化鈣在相同反應(yīng)條件下產(chǎn)率提高25%。采用TGA、BET、CO_2-TPD和IR對(duì)催化劑進(jìn)行表征,結(jié)果表明,溶膠-凝膠法制備納米氧化物過程中并未形成新晶相,但CaO的結(jié)晶度提高,且催化劑的比表面積、孔徑和孔體積都明顯增大,說明在該反應(yīng)中,催化劑的表面結(jié)構(gòu)是影響其催化效果的重要因素。采用共沉淀法制備不同納米復(fù)合型固體堿,分別考察該類固體堿在催化油脂-碳酸二甲酯-甲醇連續(xù)雙酯交換反應(yīng)體系制備生物柴油中的反應(yīng)性能。實(shí)驗(yàn)結(jié)果表明,納米復(fù)合堿MgO-CaO具有良好的催化效果。油/酯/醇摩爾比1/1/6,催化劑用量10%,反應(yīng)4h生物柴油產(chǎn)率最高為97.39%。采用TGA、BET、CO_2-TPD和IR對(duì)催化劑進(jìn)行表征,結(jié)果表明,焙燒溫度對(duì)MgO-CaO粉末的晶相形貌基本無(wú)影響,但對(duì)催化劑表面結(jié)構(gòu)和催化活性的影響非常大,800℃焙燒得到的納米MgO-CaO比表面積、孔徑和孔體積最大,催化劑上MgO和CaO分布均勻。論文中還通過反向沉淀法制備納米氫氧化鈣,焙燒后得到其衍生物納米氧化鈣,并以此為催化劑考察其催化油脂-碳酸二甲酯-甲醇連續(xù)雙酯交換反應(yīng)體系制備生物柴油的性能。實(shí)驗(yàn)結(jié)果表明,以納米氫氧化鈣為前軀體制備的納米氧化鈣催化活性較高,油/酯/醇摩爾比1/1/8,催化劑用量10%,反應(yīng)1h生物柴油產(chǎn)率最高為94.24%,比相同條件下普通氧化鈣產(chǎn)率提高40%,比溶膠-凝膠法納米氧化鈣反應(yīng)時(shí)間縮短3h。采用TGA、BET、CO_2-TPD和IR對(duì)催化劑進(jìn)行表征,結(jié)果表明,不同于溶膠-凝膠法,焙燒溫度對(duì)該催化劑表面結(jié)構(gòu)幾乎無(wú)影響,而是通過改變催化劑的表面堿度和活性位點(diǎn)數(shù)量來(lái)影響催化劑活性。
[Abstract]:In this paper, KF/ 緯 -Al _ 2O _ 3 catalyst was prepared by impregnation method and blending method. The catalyst was used as catalyst to study the catalytic performance of KF/ 緯 -Al _ 2O _ 3 catalyst in the continuous transesterification system of lipide-dimethyl carbonate and methanol to prepare biodiesel. The nanocatalyst KF/ 緯 -Al _ 2O _ 3 prepared by blending method has higher catalytic activity. When the molar ratio of oil / ester / alcohol is 1 / 1 / 8, the amount of catalyst is 5 and the reaction time is 30 min, the biodiesel yield can reach 98.82%, which is higher than that of KF/ 緯 -Al _ 2O _ 3 prepared by impregnation under the same reaction conditions. Compared with the traditional methanol-oil ester exchange system, the biodiesel system was prepared. The time required for the system to reach 98% biodiesel yield was shortened by 40 mins. The catalyst was characterized by TGABETCO _ 2-TPD and IR. The results show that the main reason for the high activity of KF/ 緯 -Al _ 2O _ 3 catalyst is that the new strong basic site K _ 2O _ 2 is obtained during the calcination process, which greatly improves the basic strength of the catalyst. A series of nanometer alkali gold was prepared by sol-gel method. Of oxide catalysts, The catalytic properties of these solid bases in the continuous transesterification of oil, dimethyl carbonate and methanol to biodiesel were investigated. The results showed that the catalytic effect of nanometer oxide was better than that of ordinary solid bases. Nanometer CaO showed good catalytic activity. When the molar ratio of oil / ester / alcohol was 1 / 1 / 8, the amount of catalyst was 5%, the highest yield of biodiesel was 92.82% after 4 h reaction, which was 25% higher than that of ordinary calcium oxide under the same reaction conditions. The catalyst was characterized by TGABETT CO 2-TPD and IR. The results showed that no new crystalline phase was formed in the preparation of nano-oxide by sol-gel method, but the crystallinity of CaO was increased, and the specific surface area, pore size and pore volume of the catalyst were increased obviously. The surface structure of the catalyst is an important factor affecting its catalytic effect. Different nanometer composite solid bases were prepared by coprecipitation method. The reaction performance of this kind of solid base in the continuous transesterification of oil, dimethyl carbonate and methanol to biodiesel was investigated. Nanometer composite base MgO-CaO has good catalytic effect, the molar ratio of oil to ester / alcohol is 1 / 1 / 6, the amount of catalyst is 10, the highest yield of biodiesel is 97.39% for 4 h. The catalyst is characterized by TGABETCO2-TPD and IR. The calcination temperature had no effect on the crystal morphology of MgO-CaO powder, but the effect on the surface structure and catalytic activity of the catalyst was very great. The specific surface area, pore size and pore volume of nano-sized MgO-CaO calcined at 800 鈩，

本文編號(hào)：1599084