催化裂化催化剂中分子筛与含铝基质材料的绿色合成和多功能化

发布时间：2018-01-10 01:03

本文关键词：催化裂化催化剂中分子筛与含铝基质材料的绿色合成和多功能化　出处：《华东师范大学》2017年博士论文　论文类型：学位论文

【摘要】：流化催化裂化(FCC)是现代石油化工的基础与核心。FCC催化剂的主要活性组分包括Y型分子筛和活性硅铝基质。随着原油组成的日益重质化,开发适用于大分子裂化的高选择性和高活性FCC催化剂越来越迫切。本文围绕FCC催化剂活性组分Y分子筛的脱钠与脱铝改性、多孔活性基质的构筑、及其对真实油品的催化裂化性能等开展研究,取得如下结果:论文第一部分首次将硫酸铝用于NaY分子筛脱铝,实现了一步脱铝、脱钠并成功引入介孔。硫酸铝在酸性水热条件下,与NaY分子筛的骨架铝及Na+直接反应生成明矾石。通过氢氧化钠、碳酸钠、氨水、氨水蒸汽等可将明矾石物种转化为γ型氧化铝,后者是FCC催化剂的基质。最终脱铝Y分子筛的比表面积为681m~2g~(-1),介孔表面积为142m~2g~(-1)。在800℃高温水蒸气处理17小时后,脱铝Y分子筛依旧保持46%的相对结晶度,介孔表面积也保持127m~2g~(-1)。我们进一步通过XRD表征手段揭示了硫酸铝脱铝过程的机理。结果表明,NaY分子筛的脱铝程度与明矾石的生成量正相关。并且在酸性条件下,单独利用Al_3~+或SO_42~-无法对NaY分子筛进行脱铝或与NaY分子筛反应生成明矾石。我们推测,硫酸铝与NaY分子筛的骨架铝及Na+反应生成热力学更稳定的明矾石是脱铝的重要原因。另外,硫酸铝会选择性的将NaY分子筛中四元环对位铝脱除,所以该脱铝Y分子筛比传统水蒸气脱铝USY分子筛具有更多的强酸位点,更强的烷烃裂化活性和裂化氢转移指数。论文第二部分通过静电吸附作用,将SBA-15与纤维薄水铝石溶胶简单组装,经老化和焙烧等步骤制备了一种纤维氧化铝包裹SBA-15的两相SiO_2/Al_20_3复合基质材料。所得SiO_2/Al_20_3复合材料具有开放的多级孔道结构,比表面积为425m~2g~(-1),孔体积为0.97m~3g~(-1)。混合相中的γ型氧化铝可以稳定其表面积。由于硅铝物种在复合材料中的迁移,纤维氧化铝的A1-OH在复合后消失,四配位硅羟基窝铝在焙烧前后分别增加到2%和5%。由于硅铝的迁移,SiO_2/Al_2O_3复合材料同时拥有Bronsted和Lewis酸位点。尽管高温水蒸气会导致复合材料的比表面积下降,但它会促进硅铝迁移,使其具有更强的酸性。由于其开放的多级孔道结构,SiO_2/Al_2O_3复合材料比传统用浸渍法得到的硅铝材料具有更高的1,3,5-三异丙基苯(TIPB)裂化活性,并且TIPB裂化转化率在800℃高温100%水蒸气处理后保留较好。论文第三部分以拜尔石为前驱体,在无模板剂的情况下,合成了多级孔道薄水铝石。所得花状结构薄水铝石初级粒子厚度仅1～5 nm,并具有双重孔道结构。含乙醇/水/硫酸铵的反应母液为反应体系提供稳定的pH,并可以重复用于花状结构薄水铝石。通过XRD、SEM和27A1 MAS NMR等表征手段,我们发现花状结构薄水铝石逐渐从拜耳石颗粒外向颗粒内部生长。转化过程中,拜耳石相和薄水铝石相的晶粒大小和铝的配位状态保持不变,但比表面积从28m~2g~(-1)上升到221m2 g~(-1)。经过焙烧后,花状结构氧化铝的表面积高达281m2 g~(-1)。由于其开放的孔道结构和较大的孔径,花状结构γ型氧化铝对TIPB裂化的转化率是工业γ型氧化铝的近2倍。另外,花状结构γ型氧化铝的形貌在800℃高温100%水蒸气处理后保留较好。论文还考察了上述材料在接近工业FCC条件下的催化裂化性能。将新型脱铝Y分子筛和多功能化硅铝基质喷雾成小球形催化剂,在微型流化催化裂化反应装置上进行催化性能评价。经硫酸铝脱铝的Y分子筛比传统的USY拥有更好的骨架铝分布和更高的介孔表面积,前者喷雾成型的催化剂对渣油有更好的裂化转化率和汽油收率。新型脱铝Y分子筛和硅铝基质喷雾成型的催化剂,比工业FCC催化剂具有更高的渣油裂化转化率,汽油收率和液化石油气收率。
[Abstract]:Fluid catalytic cracking (FCC) is the main active component base and core of modern petrochemical.FCC catalyst consists of Y zeolite and activated silica alumina matrix. With the composition of crude oil is heavy, apply to the development of macromolecular cracking of high selectivity and high activity of FCC catalyst is more and more urgent. This paper focuses on the activity of FCC catalyst composition of Y molecular sieve and desodium dealumination, construct porous active matrix, and carry out research on real oil catalytic cracking performance. The results are as follows: the first part of the paper for the first time for aluminum sulfate NaY zeolite was achieved one-step dealumination, sodium removal and the successful introduction of mesoporous. Aluminum sulfate in acidic hydrothermal conditions, and the framework of NaY zeolite and Na+ direct reaction of aluminum alunite. By sodium hydroxide, sodium carbonate, ammonia, ammonia vapor can be transformed into species of alunite alumina, which is FCC The catalyst matrix. Finally dealuminated Y zeolite specific surface area of 681m~2g~ (-1), surface area of mesoporous 142m~2g~ (-1). In the 800 high temperature water vapor treatment after 17 hours, dealuminated Y zeolite crystallinity remained 46%, mesoporous surface area 127m~2g~ (-1). We reveal the mechanism of aluminum sulfate removal during aluminium further characterized by XRD method. The results show that the generation of dealumination degree and alunite NaY molecular sieve and positive correlation. In acidic conditions, the use of Al_3~+ or SO_42~- alone cannot sieve dealuminated NaY zeolite or reaction of alunite on NaY molecules. We speculate that the Na+ reaction thermodynamic framework aluminum and aluminum sulfate and NaY molecular sieve more stable alunite is an important cause of dealumination. In addition, aluminum sulfate selectively NaY molecular sieve element four ring para removal of aluminum, so the dealuminated Y zeolite than traditional water vapor Dealuminated USY zeolite has more stronger acid sites, the alkane cracking activity and hydrogen transfer cracking index. In the second part, through electrostatic adsorption, SBA-15 and fiber boehmite sol by simple assembly, aging and calcination. The preparation phase of SiO_2/Al_20_3 composite matrix material for fiber alumina coated SBA-15. The SiO_2/Al_20_3 composite materials with hierarchical pores open, specific surface area is 425m~2g~ (-1), pore volume of 0.97m~3g~ (-1). Gamma alumina mixed phase can stabilize its surface area. The silicon aluminum species in the composite fiber migration, alumina in composite A1-OH disappear after four coordination silicon hydroxyl aluminum in the nest before and after calcination were increased to 2% and 5%. due to the migration of silicon and aluminum, SiO_2/Al_2O_3 composite materials have both Bronsted and Lewis acid sites. Despite the high temperature water vapor will lead to composite material The specific surface area of the material decreased, but it will promote silicon aluminum migration, which has stronger acidity. The hierarchical structure of its open, aluminum silicon SiO_2/Al_2O_3 composites than the traditional impregnation method was obtained with higher 1,3,5- three isopropyl benzene (TIPB) cracking activity and TIPB conversion rate. Good retention at 800 degrees Celsius to 100% after water vapor treatment. The third part of bayerite as precursor, without template agent, mesoporous boehmite was synthesized. The structure of boehmite primary particle thickness of only 1 ~ 5 nm, and has a double pore structure. Ethanol / water / provide stable pH reaction solution of ammonium sulfate as reaction system, and can be used for flower like structure of boehmite. By XRD, SEM and 27A1 MAS NMR techniques, we found that the flower like boehmite particles gradually from bayerite particles inside extroversion Growth. In the process of transforming, bayerite phase and boehmite phase and particle size of aluminium coordination state remains unchanged, but the specific surface area from 28m~2g~ (-1) up to 221m2 g~ (-1). After calcination, the flower like structure of alumina surface area up to 281m2 g~ (-1) as. The open pore structure and large pore diameter, flower like structure of alumina on the transformation of TIPB cracking rate is nearly 2 times of industrial alumina. In addition, the morphology of flower structure alumina retained well in high temperature of 800 DEG C 100% after water vapor treatment. The paper also studied the catalytic performance of these materials in close to the industry under the condition of FCC. The new type of dealuminated Y zeolite and multi functional silicon aluminum matrix spray into small spherical catalyst, catalytic cracking reaction device in micro flow on the catalytic performance. Y molecular sieve by aluminum sulfate and aluminum is better than the traditional USY with the aluminum frame distribution And the higher surface area of mesoporous catalyst, the former spray molding has better conversion rate and yield of gasoline residue. The new catalyst dealuminated Y zeolite and silicon aluminum matrix spray molding, with residuum higher conversion rate than FCC industrial catalyst, gasoline yield and LPG yield.

【学位授予单位】：华东师范大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TE624.91

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