本文關(guān)鍵詞： 鎳 催化劑 油脂加氫 納米碳酸鈣 載體　出處：《江南大學》2015年碩士論文　論文類型：學位論文

【摘要】：油脂加氫技術(shù)是在催化劑的作用下,氫氣與脂肪酸甘油酯中的不飽和鍵反應(yīng),使其達到飽和,形成硬化油;后硬化油經(jīng)水解等過程制備得硬脂酸。硬脂酸在日化、醫(yī)藥和食品加工等行業(yè)有著廣泛應(yīng)用。催化劑是油脂加氫技術(shù)的關(guān)鍵之一,直接決定硬化油/硬脂酸的質(zhì)量和性能,且對成本影響也很大。因此研究高活性,低成本的加氫催化劑是油脂行業(yè)和催化劑領(lǐng)域的主要發(fā)展趨勢。本文重點研究了使用納米碳酸鈣作催化劑載體制備的一種負載型鎳基催化劑,對其表征并研究它對棕櫚油加氫的催化性能,主要內(nèi)容如下:(1)考察了多種不同載體對催化劑活性的影響。納米碳酸鈣在工業(yè)上廉價易得;本文將工業(yè)級的納米碳酸鈣用作催化劑載體,研究表明納米碳酸鈣作載體制備的鎳基催化劑對油脂的加氫效果達到工業(yè)要求水平。打破了多孔型材料作催化劑載體的常規(guī)。(2)在提高活性方面,分別考察了活性組分的制備方法、負載量、制備條件等對催化劑活性的影響。結(jié)合產(chǎn)物碘值及XRD對催化劑的表征。結(jié)果顯示,制備方法選擇沉淀法要優(yōu)于絡(luò)合沉淀法和浸漬法。通過TG、H2-TPR、XRD、TEM等表征手段并結(jié)合產(chǎn)物碘值對以納米碳酸鈣作催化劑載體制備油脂加氫催化劑的條件進行了優(yōu)化,研究表明,選擇Na2CO3作沉淀劑,活性組分金屬鹽Ni(NO3)2溶液濃度為0.5 mol/L,鎳負載量為30 wt%,沉淀溫度為65℃,環(huán)境p H值調(diào)至8左右,在350℃下焙燒2 h;然后,設(shè)定H2流速為30~40 m L/min,在400℃下還原2 h,所制備的催化劑催化活性最高。然后,以產(chǎn)物碘值為依據(jù),考察了氫化工藝條件的影響,確定工藝條件為:催化劑用量0.7‰,反應(yīng)溫度200℃,H2壓力2.0 Mpa,反應(yīng)2 h時油脂產(chǎn)物碘值最低,轉(zhuǎn)化率最高,催化劑加氫效果最好。(3)研究了添加金屬促進劑對催化劑活性的影響,分別用沉淀法制備了多種負載型二元鎳基催化劑。結(jié)合產(chǎn)物碘值和H2-TPR、XRD等表征手段,確定添加Al和Co作促進劑均可提高催化劑活性,最佳促進劑選擇Al,且當n(Ni):n(Al)=6:1時原料棕櫚油碘值可由原來的32.14 g I2/100 g降低至0.33 g I2/100 g,轉(zhuǎn)化率達到98.97%。對棕櫚油加氫反應(yīng)結(jié)果表明,以上優(yōu)化條件下制得的催化劑,活性高,性能穩(wěn)定,基本達到工業(yè)進口催化劑水平,且相對成本較低,具有良好應(yīng)用前景。
[Abstract]:The technology of oil hydrogenation is that hydrogen reacts with unsaturated bond in fatty acid glycerol ester under the action of catalyst to make it saturated to form hardened oil. Stearic acid is prepared by hydrolysis of post-hardened oil. Stearic acid is widely used in daily chemical, pharmaceutical and food processing industries. Catalyst is one of the key technologies of oil hydrogenation. The quality and performance of hardened oil / stearic acid are directly determined, and the cost is also greatly affected. Therefore, the study of high activity. Low cost hydrogenation catalyst is the main development trend in oil industry and catalyst field. This paper focuses on a supported nickel based catalyst prepared with nanometer calcium carbonate as catalyst carrier. The main contents are as follows: (1) the effects of different supports on the catalytic activity of the catalyst were investigated. Nano-calcium carbonate is cheap and easy to obtain in industry. In this paper, industrial nanometer calcium carbonate was used as catalyst support. The results showed that the hydrogenation efficiency of the nickel based catalyst prepared on the support of nanometer calcium carbonate was up to the standard of industrial requirement, which broke with the conventional method of porous material as the catalyst carrier, and improved the activity of the catalyst. The effects of preparation method, loading amount and preparation conditions on the activity of the catalyst were investigated respectively. The catalyst was characterized by iodine value of the product and XRD. The preparation method is better than complex precipitation method and impregnation method. The conditions of preparing oil hydrogenation catalyst with nanometer calcium carbonate as catalyst carrier were optimized by means of TEM and iodine number of product. The results showed that Na2CO3 was chosen as precipitant. The concentration of active component metal salt Ni(NO3)2 solution is 0.5 mol / L, the nickel loading amount is 30 wts, the precipitation temperature is 65 鈩，

本文編號：1443640