Pd-β/MCM-41复合分子筛加氢裂解废食用油性能研究

以碱处理β沸石作为硅铝源,以CTAB为模板剂,合成了β/MCM-41介孔-微孔复合分子筛,以其为载体制备Pd-β/MCM-41复合分子筛催化剂,利用XRD、N₂吸附-脱附、NH₃-TPD和XRF等技术对其进行了表征,并与γ-Al₂O₃、USY、ZSM-5等载体制备的催化剂比较了废食用油加氢裂解活性。结果表明：β/MCM-41复合分子筛同时具备β沸石和MCM-41分子筛的结构,β/MCM-41为载体时,Pd-β/MCM-41催化剂具有适宜的中强酸性中心,适宜的孔道分布结构,催化剂加氢裂解废食用油的活性最高。此外还考察了催化剂制备条件对废食用油加氢裂解反应的影响,结果表明：采用离子交换法制备负载量2%的Pd-β/MCM-41复合分子筛催化剂、焙烧温度为500 ℃时,催化剂对废食用油加氢裂解的效果最好。此时,原料油的转化率可以达到85.9%,生物汽油的收率可以达到16.4%,生物柴油的收率达到17.8%,且此催化剂水热稳定性较好,再生性能良好,工业化应用前景较好。     

MCM-41介孔分子筛近期应用研究进展

介绍了近年来MCM-41型介孔分子筛的应用及发展方向,以及一些新型MCM-41材料的出现。其中在吸附和催化方面都涉及到分子筛大量改性的研究。此外,分子筛在医药领域作为缓释剂的发展以及电子领域膜的制备也有新的发现。在MCM-41型介孔分子筛不同的应用中,充当载体的MCM-41型介孔分子筛在负载物的协助下可以得到更有效的实验结果。根据目前的应用发现,发掘MCM-41分子筛的更大潜力是未来研究的进展方向。     

MCM-41-HY介孔-微孔复合分子筛的水热合成

以微孔分子筛HY浆液为母液,合成介孔-微孔复合分子筛MCM-41-HY。通过XRD、NH_3-TPD和N_2吸附-脱附等手段对复合材料进行了表征,并对复合分子筛的水热稳定性进行了考察。结果表明,复合分子筛MCM-41-HY具有中孔分子筛MCM-41和微孔HY型沸石的特点,并且与纯MCM-41分子筛相比,复合分子筛的酸强度明显增强,水热稳定性提高。     

MCM-41介孔分子筛的合成、改性及应用研究进展

介绍了MCM-41介孔分子筛的优点,主要表现在具有较大的比表面积,孔体积与孔径和可调变等。综述了MCM-41介孔分子筛的合成方法与改性研究现状,阐述了MCM-41介孔分子筛的应用研究进展。     

ZSM-5/MCM-41复合分子筛的微波合成及催化性能

用微孔沸石硅源法微波合成ZSM-5/MCM-41复合分子筛,采用XRD、BET和NH₃-TPD技术对合成分子筛进行表征。结果表明,复合分子筛具有类MCM-41 的典型六方介孔结构,同时具有中孔和微孔结构,复合分子筛的总酸量介于HMCM-41酸量与HZSM-5酸量之间。利用脉冲微反装置考察合成分子筛的邻二甲苯异构化催化性能。结果表明,ZSM-5/MCM-41复合分子筛具有高于同硅铝比的MCM-41、ZSM-5和ZSM-5/MCM-41的机械混合物的催化活性。     

环己烷催化氧化制环己酮的MCM-41催化剂研究

以十六烷基三甲基溴化铵为模板剂,正硅酸乙酯为硅源,采用水热合成法制备纯MCM-41分子筛和掺杂不同金属离子的MCM-41分子筛,并采用等体积浸渍法将一定量的金属离子负载在纯MCM-41分子筛内表面上,制备了负载型和掺杂型2类不同的MCM-41分子筛催化剂.分别考察了负载和掺杂的金属种类、金属Cr负载和掺杂量等对环己烷氧化制环己酮中的催化活性和选择性的影响.研究表明:采用掺杂制备的MCM-41分子筛催化剂活性明显高于负载型MCM-41分子筛催化剂;Cr掺杂量增加,虽然环己烷氧化转化率增加,但产物选择性下降;掺杂Cr的MCM-41分子筛催化剂,用于环己烷氧化制环己酮,在Si与Cr摩尔比为50以下、反应温度75℃、H2O2与环己烷摩尔比为1.2的条件下,环己烷的转化率可达60%左右,环己酮和环己醇的总选择性可达94%以上.     

MCM-41介孔分子筛改性研究进展

介绍了有序介孔材料的定义和分类,MCM-41介孔分子筛、合成方法和形成机理,针对其MCM-41目前存在的一些问题,综述了国内外对MCM-41介孔分子筛最新的改性研究进展。     

MCM-41分子筛固载羧基钯（Ⅱ）配合物催化剂的制备、表征和催化性能（Ⅰ）催化剂的制备与表征

合成了一系列新的MCM-41分子筛固载羧基钯（Ⅱ）配合物催化剂,并利用XRD、XPS、FT-IR和FT-Raman等技术对催化剂进行了表征。研究表明,MCM-41分子筛表面的Si—OH基可与三乙氧基硅烷类化合物发生作用,合成了表面羧基功能化的介孔MCM-41材料。 MCM-41分子筛在有机功能化过程中虽然其比表面积、孔容和平均孔径有所减少,但其孔结构未被破坏。MCM-41分子筛载体上的—COOH配体通过与Pd(OAc)2中OAc基的交换反应而与Pd2＋发生配位。     

层状硅酸盐矿物合成MCM-41介孔分子筛的研究进展

文章分别概述了层状硅酸盐矿物和MCM-41介孔分子筛的优势,以及层状硅酸盐矿物合成MCM-41介孔分子筛的优势;综述了膨润土、高岭土、海泡石等层状硅酸盐矿物的提纯与活化方法,层状硅酸盐矿物合成MCM-41介孔分子筛的研究进展;最后就层状硅酸盐矿物合成MCM-41分子筛给出了自己的见解,提出了一些不足之处,并对其发展前景进行了展望。     

MCM-41分子筛模板剂脱除研究进展

MCM-41分子筛具有较高比表面积和均一规整的孔道结构,脱除MCM-41的模板剂是影响其应用的关键因素之一。对MCM-41分子筛模板剂的脱除方式和脱除机理的研究进展进行了综述,着重分析了脱除方式对分子筛结构、酸性、稳定性和比表面积等性质的影响。     

Hydrocracking of petroleum gas oil over NiW/MCM-48-USY composite catalyst

MCM-48-USY composite materials were prepared by coating USY zeolite by a layer of MCM-48 mesoporous material at different meso/microporous ratios (SiO₂/USY ratios of 0.1, 0.2, 0.3, 0.4, 0.5) and used as support for nickel and tungsten. The NiW/MCM-48-USY catalysts were prepared using the incipient wetness method. The prepared catalysts were characterized by TPD-TGA acidity, TGA thermal stability, BET surface area, pore volume, pore size, XRD, SEM and TEM and then tested for hydrocracking of petroleum gas oil at reaction temperature of 450 °C, contact time of 90 min and catalyst to gas oil ratio of 0.04. In all prepared samples, the catalyst activity and properties were improved with increasing SiO₂/USY ratio and found that maximum values of a total conversion and liquid product (total distillate fuels) were obtained at SiO₂/USY ratio of 0.5. Finally, the obtained results from hydrocracking of gas oil over composite MCM-48-USY catalysts were compared with those obtained over physically mixed USY and MCM-48 catalysts.     

改性Y分子筛加氢裂化催化剂耐氮性能的研究

采用水热处理法制备了两种改性Y型分子筛NTY和USY，并用含吡啶正庚烷和甲苯为模型化合物，对引入这两种分子筛制备的加氢裂化催化剂性能进行了考察，发现引入表面积大、二次孔多、结晶度高的NTY分子筛制备的加氢裂化催化剂，其耐氮性能明显优于USY分子筛制备的催化剂。     

Utilization of ZSM-5/MCM-41 composite as FCC catalyst additive for enhancing propylene yield from VGO cracking

A micro-mesoporous ZSM-5/MCM-41 composite molecular sieve (ZM13) was synthesized and tested as an FCC catalyst additive to enhance the yield of propylene from catalytic cracking of vacuum gas oil (VGO). The catalytic performance of the additive was assessed using a commercial equilibrium USY FCC catalyst (E-Cat) in a fixed-bed micro-activity test unit (MAT) at 520?°C and various catalyst/oil ratios. MCM-41, ZSM-5 and two ZSM-5/MCM-41 composites were systematically characterized by complementary techniques such as XRD, BET, FTIR and SEM. The characterization results showed that the composites contained secondary building unit with different textural properties compared to pure ZSM-5 and MCM-41. MAT results showed that the VGO cracking activity of E-Cat did not decrease by using these additives. The highest propylene yield of 12.2 wt% was achieved over steamed ZSM-5/MCM-41 composite additive (ZM13) compared with 8.6 wt% over conventional ZSM-5 additive at similar gasoline yield penalty. The enhanced production of propylene over composite additive was attributed to its mesopores that suppressed secondary and hydrogen transfer reactions and offered easier transport and accessibility to active sites. Gasoline quality was improved by the use of all additives except MCM-41, as octane rating increased by 6?C12 numbers.     

Catalyst design and development for upgrading aromatic hydrocarbons

Background and strategy of catalyst development for upgrading aromatic hydrocarbons are intensively discussed. Originally prepared catalysts (hydrogenation and hydrocracking catalysts) were used for accelerated aging tests. Though each catalyst showed superior catalytic performance as compared to commercially available catalysts, a severe deactivation was observed on the hydrocracking (HC) catalysts. A new type of HC catalyst was designed and prepared, based on the understanding of catalyst deactivation. High silica NaY zeolites were synthesized using crown-ether. USY zeolites were then prepared by ion exchange, steaming and calcining. Surface properties and catalytic functions of well-crystallized USY zeolites were investigated to develop practical HC catalysts. The Ni–W catalyst prepared using the newly prepared USY zeolite showed a considerable improvement in the HC activity.     

Thermochemical conversion of polymer wastes into hydrocarbon fuels over various fluidizing cracking catalysts

A mixture of hospital post-commercial polymer waste (LDPE/HDPE/PP/PS) was pyrolyzed over various catalysts using a fluidized-bed reactor operating isothermally at ambient pressure. The yield of volatile hydrocarbons with zeolitic catalysts (ZSM-5 > MOR > USY) were higher than with non-zeolitic catalysts (MCM-41 > ASA). MCM-41 with large mesopores and ASA with weaker acid sites resulted in a highly olefinic product mixture with a wide carbon number distribution, whereas USY yielded a saturate-rich product mixture with a wide carbon number distribution and substantial coke levels. The systematic experiments discussed in this paper show that the use of various catalysts improves the yield of hydrocarbon products and provide better selectivity in the product distributions. A novel developed model based on kinetic and mechanistic considerations which take into account chemical reactions and catalyst deactivation for the catalytic degradation of commingled polymer waste has been investigated. This model represents the benefits of product selectivity for the chemical composition such as alkanes, alkenes, aromatics and coke in relation to the performance and the particle size selection of the catalyst used as well as the effect of the fluidizing gas and reaction temperature.     

Synthesis, characterization, and catalytic properties of a hydrothermally stable Beta/MCM-41 composite from well-crystallized zeolite Beta

A Beta/MCM-41 composite has been synthesized with a new method by using well-crystallized zeolite Beta as silica and aluminum source. The prepared composite was characterized by XRD, FTIR, N₂ adsorption/desorption at 77 K, FE-SEM, DTG, ²⁹Si MAS NMR spectral techniques. It was shown that the composite consisted of a highly ordered mesoporous MCM-41 phase and a zeolite Beta phase. Its hexagonal mesoporous structure was still retained after statically treated for 120 h in boiling water. In contrast, the structure of generally synthesized Al-MCM-41 nearly completely collapsed. This might be attributed to the assembly of the dissolved fragments such as the first and/or secondary structural units of zeolite Beta into the mesoporous structure around surfactant micelles. This is supported by the catalytic result that the prepared composite showed higher activity and selectivity for medium fraction in hydrocracking of Daqing vacuum residue than the parent zeolite Beta, the Al-MCM-41 as well as the mechanical mixture of these two materials.     

超稳Y分子筛脱铝改性的研究进展

超稳Y分子筛(USY)在石油化工催化领域应用广泛,尤其是作为加氢裂化和异构化反应的催化剂。随着工业化的发展,超稳Y分子筛逐渐满足不了催化剂的要求,达不到生产目的,而脱铝的超稳Y分子筛(DUSY)作为催化剂载体或活性组分的效果比母体USY分子筛要好,因此对脱铝改性的USY分子筛的研究引起关注。综述超稳Y分子筛的制备与脱铝改性方法的研究进展,改性方法包括水热法、化学法和水热-化学法,重点介绍化学脱铝改性对超稳Y分子筛的性质影响,展望超稳Y分子筛脱铝改性的发展方向。     

杂多酸-金属双功能催化剂在庚烷异构化中的研究进展

简述了双功能催化剂上正庚烷的异构化机理,综述了负载杂多酸和金属的MCM-41、SiO2、USY、ZrO2、TUD-1、β沸石双功能催化剂上正庚烷异构化的研究进展,重点介绍了正庚烷异构化中杂多酸-金属双功能催化剂催化性能的影响因素。包括催化剂酸性、孔结构、杂多酸含量、金属含量、反应条件等。对杂多酸-金属双功能催化剂的优点和不足进行了总结,并预测了该类催化剂的发展趋势。     

Single-event-lumped-parameter hybrid (SELPH) model for non-ideal hydrocracking of n-octane

Hydrocracking of normal octane was carried out at temperatures from 493 to 548 K and pressures of 15 and 35 bar. The experiments were performed on USY zeolite loaded with 0.25 wt.% Pt. The selected experimental conditions allowed a transition from ideal to non-ideal hydrocracking. Single-event kinetic rate constants were estimated in a first stage, using only the ideal-hydrocracking data and a single-event-ideal-hydrocracking model. The estimates of the first stage were used in a second stage in which a single-event-lumped-parameter hybrid (SELPH) model for non-ideal hydrocracking was used. The (SELPH) kinetic model was able to accurately describe the transition from ideal to non-ideal hydrocracking.