多级孔Y和Beta分子筛加氢裂化催化性能研究

发布时间：2018-01-12 06:29

本文关键词：多级孔Y和Beta分子筛加氢裂化催化性能研究　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着全球轻质石油资源的大量消耗,原油重质化、劣质化现象不断加剧,与此同时随着环保法规日趋严格,使得石油产品的有效利用和清洁生产逐渐受到人们的关注。加氢裂化技术作为重油轻质化、劣质油品改质和炼化一体化的重要加工手段,具有生产方案灵活、原料适应性强、目标产物选择性高、产品质量好等优点,得到工业上的广泛应用。加氢裂化技术的核心是催化剂,加氢裂化催化剂是典型的双功能催化剂,其中的酸性组分主要是由沸石分子筛组成,加氢组分主要由金属组分所提供。在酸性组分上主要发生芳烃和环烷烃的开环反应、正构烷烃加氢裂化、脱烷基和异构化。本论文主要是以Ni-Mo双金属组分作为加氢裂化催化剂的加氢组分,以多级孔Y型和Beta型分子筛作为加氢裂化催化剂的裂化活性组分。Y型分子筛由于其FAU型拓扑结构使得其具有良好的吸附性、酸性、离子交换性能和选择性,在多种催化反应中表现出优异的催化性能。Y型分子筛虽然拥有相对较大的超笼结构,但由于其相对较小的孔口和狭窄细长的孔道,导致大分子反应物不能够在孔道内有效扩散从而减少了在催化剂内表面的利用率,同时反应后的产物也很难从孔道中扩散出去,将很容易导致二次裂化以致结炭。Beta分子筛孔道呈现无笼状结构,是唯一具有三维十二元孔道结构的高硅沸石,开环产物较易发生扩散,有利于减少二次裂化反应发生的几率,其独特的拓扑结构使其具有良好的热稳定性、耐酸性、抗结焦性。而且以beta制备的催化剂有优异的加氢异构活性、产品质量好、抗氮能力强、较低的失活速率。加氢裂化反应中加入beta沸石可以促进开环反应的发生。以beta沸石制备的加氢裂化催化剂中间馏分油选择性提高,柴油凝点降低。多级孔beta沸石在加氢裂化反应中能够有更好的裂化性能、更高的汽油和中间馏分油的选择性,因而在工业中得到广泛应用。Beta和y型沸石由于其固有的微孔结构和适宜的酸性,作为加氢裂化催化剂的载体和酸性中心,表现出裂解活性高、反应温度低及稳定性好等优点。然而,沸石的微孔尺寸限制了大分子烃的接近和分子在孔道内的扩散,从而导致过度裂解以致结焦等问题。本研究采用具有多级孔结构的beta和y型沸石分子筛替代微孔分子筛作为加氢裂化的催化剂,通过二次中孔的引入,改善沸石分子筛活性位的可接近性和扩散问题。基于此,利用抚顺石油化工研究院提供的三种后处理法制备的多级孔y分子筛tsy-a、tsy-b和tsy-c以及本课题组合成了两种不同硅铝比的多级孔beta沸石β-1和β-2,并将五种多级孔分子筛分别与氧化铝、硝酸镍、氧化钼采用共混合法法制备加氢裂化催化剂,并以催化裂化柴油为原料,在实验室采用微型反应器进行工艺评价,重点考察了分子筛的比表面积和酸性质对催化柴油加氢裂化活性,芳烃的饱和率和开环率的影响,同时还考察了温度、体积空速,氢油比对催化剂加氢开环性能的影响。表征结果表明,TSY-A分子筛经过后处理改性之后得到TSY-B和TSYC分子筛,改性后的Y分子筛BET比表面积、外比表面积、酸性和酸强度得到明显提高。虽然改性后的TSY-B和TSY-C分子筛结晶度有点下降,但仍保持良好的骨架结构且能在保持分子筛微孔结构不变的情况下将中孔结构引入分子筛晶体内形成多级孔结构。利用软模板剂法制备SiO2/Al2O3分别为25.5和15.7的β-1和β-2两种Beta分子筛,孔径分布比较集中,都有较大的平均孔径和孔体积。其中β-2分子筛外比表面积达到了419m2/g,拥有更高的总酸量、B酸量和酸强度。通过比较不同类型的分子筛制成的加氢裂化催化剂的加氢裂化催化结果。催化结果表明,分子筛的BET表面积、外表面积、酸量以及酸强度与加氢裂化性能相关。其中分子筛的孔径和孔体积也对加氢裂化性能也有一定的影响。在不同实验参数温度、体积空速和氢油比条件下考察对加氢裂化性能的影响,催化结果表明随着温度的升高,加氢饱和率和多环芳烃开环率不断增加,在340℃条件下多环芳烃开环率达到最高值;随着体积空速的增加,加氢饱和率和多环芳烃开环率不断减少;随着氢油体积比的增加,加氢饱和率和多环芳烃开环率不断增加。
[Abstract]:With a large number of global consumption of light petroleum resources, heavy crude oil, the poor quality of the growing phenomenon, at the same time with the increasingly stringent environmental regulations, the effective utilization of petroleum products and cleaner production has gradually attracted people's attention. The hydrocracking technology as an important means of processing heavy oil, modified and inferior oil refinery, with production flexible, strong adaptability of raw materials, high selectivity, good product quality and other advantages, is widely used in industry. The core of hydrocracking catalyst, hydrocracking catalyst is a typical dual function catalyst, the acidic group is mainly composed of zeolite molecular sieve composition, hydrogenation component provides made of metal components. The ring opening reaction of aromatic and naphthenic hydrocarbon mainly occurs in the acidic components of the n-alkanes hydrocracking, dealkylation and isomerization in the thesis. Is the hydrogenation group to Ni-Mo double metal component as hydrocracking catalyst, with multi hole Y type and Beta type molecular sieve cracking activity group as hydrocracking catalyst.Y zeolite as the topological structure of FAU type such that it has good acidity, adsorption, ion exchange properties and selectivity and in a variety of catalytic reactions exhibit excellent catalytic properties of.Y molecular sieve has relatively large supercage structure, but because of its relatively small orifice and narrow channels, leading to large molecules in the pore diffusion can not effectively reduced the surface utilization ratio in the catalyst, the product at the same time after the reaction is difficult to spread out from the channels, will easily lead to two times that of carbon.Beta cracking molecular sieve showed no cage like structure, is only twelve yuan with a three-dimensional pore structure of high silicon zeolite, ring opening products More prone to diffusion, helps to reduce the probability of two cracking reaction, its unique topological structure which has good thermal stability, acid resistance, anti coking. And the catalyst prepared by beta have excellent hydroisomerization activity, good product quality, nitrogen resistant ability, the inactivation rate is low. Adding beta zeolite hydrocracking reaction can promote the ring opening reaction. The beta zeolite preparation of hydrocracking catalyst for middle distillate selectivity, diesel pour point reduction. Multi pore beta zeolite can have better cracking performance in the hydrocracking reaction, higher selectivity and intermediate gasoline the distillate oil, so it is widely used in.Beta and Y type zeolite micropores due to its inherent structure and suitable acidity in the industry, as the carrier of the hydrocracking catalyst and acid center, showing high cracking activity, low reaction temperature and Good stability. However, the pore size of zeolite diffusion limited proximity and macromolecular hydrocarbon in the pores, resulting in excessive cracking that coking. This study used beta and Y type zeolite molecular sieve to replace hierarchical pore structure of microporous molecular sieve as catalyst for hydrocracking, by introducing two in the hole, improve the zeolite active site accessibility and diffusion problems. Based on this, provided by Fushun Petrochemical Research Institute of three kinds of postprocessing prepared by multistage mesoporous molecular sieve y tsy-a, tsy-b and tsy-c and the combination of two different Si / Al ratio of hierarchical porous zeolite beta beta -1 and beta -2, and five kinds of hierarchical zeolites with alumina, nickel nitrate, molybdenum oxide by blending method by hydrogenation cracking catalyst and catalytic cracking diesel as raw materials in the laboratory using micro reactor. For process evaluation, and focuses on the molecular sieve surface area and acid properties of diesel catalytic hydrocracking activity, aromatics saturation and ring opening rate and also the effects of temperature, space velocity, effect of hydrogen oil ratio on catalytic hydrogenation of open loop performance. The characterization results show that after after the treatment of modified TSY-A molecular sieve TSY-B and TSYC molecular sieve modified Y molecular sieve BET specific surface area, specific surface area, acidity and acid strength improved obviously. Although TSY-B and TSY-C molecular sieve after crystallization is decreased, but still maintain good bone structure and in keep the molecular sieve pore structure unchanged the mesoporous structure into the zeolite crystal in the form of hierarchical pore structure. Using soft template prepared by SiO2/Al2O3 were 25.5 and 15.7 of the beta -1 and beta -2 two Beta molecular sieve, the pore size distribution concentrated, have large The average pore size and pore volume. The beta zeolite -2 external surface area reached 419m2/g, with higher B total acidity, acidity and acid strength. The catalytic hydrocracking hydrocracking catalyst prepared by molecular sieve and the comparison of different types. The catalytic results show that molecular sieve BET surface area, appearance the area, and the acid strength and acid related hydrocracking performance. The pore volume and pore diameter of molecular sieve on the hydrocracking performance also has a certain influence. In different experimental parameters of temperature, space velocity and ratio of hydrogen to oil under the condition of investigation on the hydrocracking performance, the catalytic results show that with the increase of temperature the rate of hydrogenation, and polycyclic aromatic ring opening rate increase, the open-loop rate reached the highest value at 340 deg.c for polycyclic aromatic hydrocarbons; with the increase of space velocity, hydrogenation rate and polycyclic aromatic ring opening rate continues to decrease; with the volume ratio of hydrogen to oil The increasing of the hydrogenation saturation and the ring opening rate of polycyclic aromatic hydrocarbons (PAHs) are increasing.

【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE624.9

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