本文選題：Zn-MCM-48　切入點(diǎn)：分子篩催化劑　出處：《東北石油大學(xué)》2017年碩士論文

【摘要】：國六汽油新標(biāo)即將在全國范圍供應(yīng),新的汽油標(biāo)準(zhǔn)要求大幅度降低硫、錳以及烯烴含量,而我國高辛烷值汽油資源不足,為了彌補(bǔ)低硫、無錳帶來的辛烷值損失,必須大力發(fā)展烷烴異構(gòu)化技術(shù)獲得高辛烷值汽油調(diào)和組分。其中,正庚烷異構(gòu)化反應(yīng)是獲得高辛烷值汽油的重要手段之一。由于MCM-48介孔分子篩具有高比表面積利于活性組分分散,以及具有三維螺旋孔道結(jié)構(gòu)有利于傳輸物料,可調(diào)變的孔徑則具有擇形催化作用。但是純硅MCM-48介孔分子篩缺乏活性中心,熱穩(wěn)定性差。將金屬以負(fù)載或原位摻雜的方式引入MCM-48分子篩骨架可以增強(qiáng)其熱穩(wěn)定性,增加分子篩中氧化還原活性位或酸堿活性位。因此本文制備了不同金屬(Ni、Co、Zn)改性的MCM-48分子篩,并通過X射線衍射分析(XRD)、N2吸附-脫附分析、傅里葉變換紅外光譜分析(FT-IR)、掃描電鏡(SEM)、NH3程序升溫脫附(NH3-TPD)等表征手段考察金屬引入對分子篩結(jié)構(gòu)、酸性、穩(wěn)定性的影響,同時以改性MCM-48為載體,Ni為活性組分,制備Ni/M(Ni、Co、Zn)-MCM-48雙功能催化劑,考察其催化正庚烷異構(gòu)化反應(yīng)性能。主要內(nèi)容如下:1.以水熱合成法合成原位摻雜鎳、鈷、鋅的MCM-48介孔分子篩,并考察了引入雜原子對MCM-48介孔分子篩結(jié)構(gòu)和性能的影響。表征結(jié)果表明:當(dāng)物質(zhì)的量配比為0.98 TEOS:0.558 CTAB:0.469 NaOH:57.64 H2O:0.02 M時,成功合成了具有立方相Ia3d結(jié)構(gòu)的M-MCM-48(M=Ni,Co,Zn)分子篩,金屬部分進(jìn)入分子篩骨架并改變了材料的酸性質(zhì)。2.采用浸漬法將活性組分Ni負(fù)載到不同金屬改性MCM-48分子篩載體上來制備Ni/M-MCM-48催化劑,并以庚烷異構(gòu)化為探針反應(yīng),考察了金屬負(fù)載量、還原溫度和反應(yīng)時間、反應(yīng)溫度以及重時空速和氫烴比等對Ni/Zn-MCM-48催化性能的影響。結(jié)果表明:在金屬負(fù)載量為4%,還原溫度為400oC,還原時間為4h,反應(yīng)溫度為260oC,WHSV為5.1h-1,氫烴摩爾比為2時,催化劑庚烷異構(gòu)化性能較好,正庚烷轉(zhuǎn)化率和異庚烷選擇性分別達(dá)到45%和62%。
[Abstract]:The new gasoline standard will soon be available nationwide. The new gasoline standard requires that the contents of sulfur, manganese and olefins be greatly reduced, while the high octane number gasoline resources in China are insufficient. In order to make up for the loss of octane number caused by low sulfur and no manganese,It is necessary to develop the technology of isomerization of alkanes to obtain high octane gasoline blending components.Among them, n-heptane isomerization is one of the important methods to obtain high octane gasoline.Because MCM-48 mesoporous molecular sieves have high specific surface area to facilitate active component dispersion and three-dimensional helical pore structure to facilitate the transport of materials, adjustable pore size has shape selective catalysis.However, pure silicon MCM-48 mesoporous molecular sieves lack active centers and have poor thermal stability.Introducing metal into MCM-48 molecular sieve skeleton by loading or in situ doping can enhance its thermal stability and increase the redox active sites or acid-base active sites in the molecular sieve.In this paper, MCM-48 molecular sieve modified by different metals NiCoCZN) was prepared, and the adsorption-desorption analysis of N2 was carried out by X-ray diffraction analysis.Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to investigate the effect of metal introduction on the structure, acidity and stability of molecular sieve, and the modified MCM-48 as carrier Ni as active component.The bifunctional catalyst of Ni- / Mg-NiCo-NiCo-ZnO-MCM-48 was prepared and its catalytic activity of n-heptane isomerization was investigated.The main content is as follows: 1.MCM-48 mesoporous molecular sieves doped with nickel, cobalt and zinc in situ were synthesized by hydrothermal synthesis. The effects of heteratoms on the structure and properties of MCM-48 mesoporous molecular sieves were investigated.The characterization results show that M-MCM-48M (MCM-48M) with Ia3d structure is successfully synthesized when the mass ratio of the material is 0.98 TEOS:0.558 CTAB:0.469 NaOH:57.64 H2O:0.02 M. the metal part enters the framework of the molecular sieve and changes the acid property of the material.The active component Ni was loaded on different metal modified MCM-48 molecular sieve carriers by impregnation method to prepare Ni/M-MCM-48 catalyst. The amount of metal loading, reduction temperature and reaction time were investigated by using heptane isomerization as probe reaction.The effects of reaction temperature, heavy space-time velocity and the ratio of hydrogen to hydrocarbon on the catalytic performance of Ni/Zn-MCM-48 were investigated.The results show that when the metal loading is 4, the reduction temperature is 400oC, the reduction time is 4h, the reaction temperature is 260oC, WHSV is 5.1h-1, and the molar ratio of hydrogen to hydrocarbon is 2, the heptane isomerization performance of the catalyst is better. The conversion of n-heptane and the selectivity of isoheptane are 45% and 62%, respectively.
【學(xué)位授予單位】：東北石油大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TE624.9
，

本文編號：1718677