本文選題：球形整體式分子篩　切入點(diǎn)：元素改性　出處：《寧夏大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：本論文報(bào)道了一種一步制備球形整體式ZSM-5分子篩的新方法。針對(duì)球形整體式ZSM-5分子篩在甲醇制取低碳烯烴反應(yīng)的過(guò)程中選擇性相對(duì)較低的問題,文章選擇在球形整體式分子篩的基礎(chǔ)上,利用金屬元素Fe和非金屬元素P的摻雜對(duì)其改性,以提高其在MTO反應(yīng)過(guò)程中低碳烯烴的選擇性。并且基于實(shí)驗(yàn)室前期的工作,我們又對(duì)球形整體式ZSM-5分子篩用AlPO4-5分子篩進(jìn)行包覆,成功制備了一種復(fù)合分子篩,進(jìn)一步達(dá)到了提高低碳烯烴選擇性的目的,具體方法如下:首先,利用一步法制備球形整體式ZSM-5分子篩的新方法,制備出球形整體式ZSM-5分子篩。對(duì)其制備路徑進(jìn)行了研究,得出以下結(jié)論:制備的小球基本沒有催化活性,對(duì)其焙燒后仍然表現(xiàn)出極差的MTO催化活性。但是用硝酸銨溶液處理過(guò)的球形整體式分子篩表現(xiàn)出良好的催化活性。在此基礎(chǔ)上我們進(jìn)一步研究了焙燒溫度對(duì)其催化效果的影響,結(jié)果表明:550℃的焙燒條件下,其MTO催化性能最佳。最后考察了工業(yè)ZSM-5不同添加量的影響,結(jié)果表明:制備的工業(yè)ZSM-5含量為18%的球形整體式分子篩表現(xiàn)出了較好的催化活性,且滿足整體式分子篩在固定床反應(yīng)器的裝管要求。其低碳烯烴的選擇性達(dá)到69.1%,乙烯選擇性達(dá)到25.9%,丙烯的選擇性達(dá)到33%。其次,在滿足制備球形整體式ZSM-5分子篩最優(yōu)制備路徑的基礎(chǔ)上,用不同含量的金屬Fe元素對(duì)其進(jìn)行改性。結(jié)果表明:3%Fe元素改性的球形整體式分子篩低碳烯烴的選擇性達(dá)到了 75.2%,而乙烯和丙烯的選擇性分別達(dá)到了 38.2%,29.4%。為了進(jìn)一步提高丙烯和低碳烯烴的選擇性,采用不同含量非金屬P對(duì)其進(jìn)行改性。結(jié)果表明:1%P改性的球形整體式分子篩最好,低碳烯烴的選擇性達(dá)到了 76.7%,乙烯的選擇性達(dá)到了 25.2%,丙烯的選擇性達(dá)到了 38.9%。最后,采用不同的合成方法制備出了 ZSM-5/AlPO4-5復(fù)合分子篩,并將其運(yùn)用到MTO反應(yīng)中。得出結(jié)論:在150℃,轉(zhuǎn)速2r/min晶化3h的均相反應(yīng)里,我們以SAPO-5分子篩為晶種制備出了具有良好催化性能ZSM-5/AlPO4-5復(fù)合分子篩,其低碳烯烴選擇性達(dá)到74.7%,丙烯選擇性達(dá)到34.9%,乙烯的選擇性達(dá)到28.2%。
[Abstract]:In this paper, a new one-step method for the preparation of spherical monolithic ZSM-5 molecular sieve is reported. The selectivity of spherical monolithic ZSM-5 molecular sieve is relatively low in the process of methanol production of low olefins. In order to improve the selectivity of low olefins in the MTO reaction process, the spherical monolithic molecular sieve was modified by doping the metal element Fe and the nonmetallic element P in order to improve the selectivity of low olefins in the process of MTO reaction. We also coated the spherical monolithic ZSM-5 molecular sieve with AlPO4-5 molecular sieve, and successfully prepared a composite molecular sieve, which further achieved the purpose of improving the selectivity of low olefins. The specific methods are as follows: first, The spherical monolithic ZSM-5 molecular sieve was prepared by a new one-step method. The preparation path of the spherical monolithic ZSM-5 molecular sieve was studied, and the following conclusions were obtained: the prepared pellets had little catalytic activity. However, the spherical molecular sieve treated with ammonium nitrate solution showed good catalytic activity. On this basis, the effect of calcination temperature on the catalytic activity was further studied. The results showed that the catalytic activity of MTO was the best at the calcination temperature of 5: 550 鈩，

本文編號(hào)：1568085