Enhanced triisopropylbenzene cracking and suppressed coking on tailored composite of Y-zeolite/amorphous silica–alumina catalyst

Catalytic composites of Y-zeolite-amorphous silica–alumina (ASA) were prepared by four different methods to enhance pre-cracking and cracking of triisopropylbenzene (TIPB). TIPB cracking on composite catalysts were compared with a conventionally prepared catalyst. The samples were characterized by FESEM, XRD, N₂-adsorption and NH₃-TPD. The catalysts performance was evaluated by triisopropylbenzene cracking at 350 ̊C in a fixed bed reactor. The coke content of the catalysts was measured by TPO. Compared to the conventional catalyst, significantly deeper cracking to benzene of about 117% higher, up to 62% lower amount of coke, and lower deactivation rate are observed for the composite catalysts.     

Kinetic and catalytic performance of a BI‐porous composite material in catalytic cracking and isomerisation reactions

Catalytic behaviour of pure zeolite ZSM‐5 and a bi‐porous composite material (BCM) were investigated in transformation of m‐xylene, while zeolite HY and the bi‐porous composite were used in the cracking of 1,3,5‐triisopropylbenzene (TIPB). The micro/mesoporous material was used to understand the effect of the presence of mesopores on these reactions. Various characterisation techniques, that is, XRD, SEM, TGA, FT‐IR and nitrogen sorption measurements were applied for complete characterisation of the catalysts. Catalytic tests using CREC riser simulator showed that the micro/mesoporous composite catalyst exhibited higher catalytic activity as compared with the conventional microporous ZSM‐5 and HY zeolite for transformation of m‐xylene and for the catalytic cracking of TIPB, respectively. The outstanding catalytic reactivity of m‐xylene and TIPB molecules were mainly attributed to the easier access of active sites provided by the mesopores. Apparent activation energies for the disappearance of m‐xylene and TIPB over all catalysts were found to decrease in the order: E_BCM > E_ZSM‐5 and E_BCM > E_HY, respectively. © 2012 Canadian Society for Chemical Engineering     

Study of cracking of large molecules over a new type meso-ZSM-5 composite zeolite

A new type meso-ZSM-5 composite zeolite with interconnected macropores and skeletons under hydrothermal conditions was prepared through zeolite degraded method. The skeletons can be templated to the morphology of network in different conditions. The physical properties of the meso-ZSM-5 composite zeolite were characterized by XRD, IR, SEM and nitrogen sorption techniques. Catalytic tests show that the meso-ZSM-5 composite zeolite catalyst exhibits high catalytic activity compared with the conventional microporous ZSM-5 zeolites for catalytic cracking of 1,3,5-triisopropylbenzene. The high 1,3,5-triisopropylbenzene conversion are mainly assigned to the presence of the hierarchical porosity of the pore walls. The macropores offer easier transport and access to the active sites and the macroporous walls built by ZSM-5 crystals provide the acidic sites for reaction.     

CFRP-PCPs复合筋混凝土柱偏压柱受力性能的试验研究

通过15根碳纤维预应力棱柱体复合筋(Carbon Fiber Reinforced Plastics Prestressed Concrete Prisms,简称"CFRPPCPs复合筋")混凝土柱进行偏心受压试验,考虑相对偏心距、复合筋配筋率、CFRP筋张拉控制应力和普通钢筋配筋率4个变化参数对复合筋混凝土柱受力性能的影响。观察了试件的受力过程及破坏形态,获取了试件开裂荷载、极限承载力、荷载-侧向变形曲线等重要数据,分析了4个变化参数对CFRP-PCPs复合筋混凝土柱偏心受压作用下的开裂荷载和极限承载力的影响规律。研究结果表明:CFRP-PCPs复合筋混凝土偏压柱与普通钢筋混凝土偏压柱的受力过程及破坏形态相似,试件的开裂荷载和极限承载力均随相对偏心距的增大而降低;提高CFRP筋张拉控制应力、增大复合筋配筋率和普通钢筋配筋率均能有效提高CFRP-PCPs复合筋混凝土柱的开裂荷载和极限承载力。     

焦油裂解制氢催化剂研究进展

高温焦炉煤气中焦油的催化裂解是高效利用焦炉煤气的重要环节。对焦油裂解催化剂包括天然矿石催化剂和人工合成催化剂的研究现状进行了总结和分析，并展望了焦油裂解催化剂的发展趋势。采用添加助催化剂、优化预处理条件、合理选择载体以及改善催化剂的结构等改性措施，可以有效提高催化剂的活性、减少积炭和增强其抗中毒的能力，从而达到延长其寿命的目的。通过“嫁接”单一催化剂的优点对多种催化剂进行整合，并科学利用材料领域的最新科研成果（如以碳纳米管作为载体），有望在催化剂的创新开发上获得突破。     

催化裂解制低碳烯烃的研究及工业应用

文章详细叙述了催化裂解制低碳烯烃的反应机理、催化裂解催化剂的分类与近几年的研究成果,讨论了影响催化裂解反应产物分布的因素,举例介绍了近十年来开发研究的新型催化裂解制低碳烯烃工艺和国内外催化裂解工业的发展情况。     

双金属改性ZSM-5-USY复合分子筛催化裂解正己烷制备低碳烯烃

为了获得催化裂解制备低碳烯烃的高效催化剂,以等体积浸渍法制备了系列单金属(Ce, Y, Zr, Mn, Cu)及双金属(Zr-Ce, Mn-Ce, Y-Ce, Cu-Ce)改性ZSM-5-USY复合分子筛催化剂,通过XRD, NH3-TPD, BET等方法表征了其物理化学性质,并将所制备催化剂用于催化裂解正己烷。结果表明,催化剂的弱酸量越多,正己烷转化率及C2~C4烯烃选择性越高,Zr-Ce共改性分子筛的催化活性较优。水蒸气处理对Zr-Ce/ZSM-5-USY催化剂的酸性及催化裂解产物分布有较大影响,经水蒸气处理的催化剂性能更稳定,可将裂解产物中低碳烯烃的选择性由20.02% (催化剂未经水蒸气处理)提高到57.55% (催化剂经水蒸气处理4 h)。研究了0.25% Zr-0.5% Ce/ZSM-5-USY催化体系的裂解反应动力学,正己烷裂解为一级反应,裂解活化能为88.93 kJ/mol。     

催化裂化碳四馏分加工方案对比

介绍了催化裂化碳四馏分的主要加工手段，以加工20万t/a催化裂化液态烃为基础，提出了4种加工流程，进行技术经济对比分析，确定了最佳的催化裂化碳四馏分加工方案。     

催化裂化油浆开发橡胶软化剂实验性研究

催化裂化油浆富含重芳烃 ,经糠醛精制后 ,抽出油可用于生产重芳烃橡胶软化剂 ,该产品性质符合橡胶软化剂JSBR -1712规格要求 ,同时 ,抽余油可作为催化裂化原料回炼 ,此工艺是进一步提高催化裂化装置的综合效益的一个有效途径     

烯烃催化裂化制丙烯的技术进展

综述了国内外烯烃催化裂化制丙烯主要工艺发展现状以及有关催化剂的研究。指出在丙烯工业的原料和工艺方面的发展方向是原料多元化和开发新技术。烯烃催化裂化技术具有操作简单和成本低廉等优势，应加快研究开发。     

半焦基催化剂裂解煤热解产物提高油气品质

利用上段热解下段催化的两段固定床反应器,针对府谷煤研究了半焦和半焦负载Co催化剂对煤热解产物的催化裂解效果。结果表明,半焦和半焦负载钴对热解产物催化裂解后,热解气收率增加,焦油收率降低,但焦油中沸点低于360℃的轻质组分含量提高,轻质焦油收率基本保持不变或略有增加。与煤在600℃直接热解相比,在热解和催化温度均为600℃,采用煤样质量20%的半焦为催化剂时焦油中轻质组分质量含量提高了约25%,轻质组分收率基本不变,热解气体积收率增加了31.2%;在热解温度600℃,催化温度500℃时,采用煤样质量5%的半焦负载钴催化剂,焦油中轻质组分质量收率和含量分别提高了约8.8%和28.8%,热解气体积收率增加了21.5%。煤热解产物的二次催化裂解的总体效果是将焦油中重质组分转化为轻质焦油和热解气。     

High activity in catalytic cracking of large molecules over a novel micro-micro/mesoporous silicoaluminophosphate

Abstract  

A novel micro-micro/mesoporous silicoaluminophosphate ZSM-5-SAPO-5/MCM-41 (define as MZS-5) composite material with regular spherical morphology was synthesized through a novel process of the self-assembly of CTAB surfactant micelles with silica-alumina source which originated from the alkaline treatment of ZSM-5 zeolite. The physical properties of the MZS-5 composite material were characterized by XRD, FT-IR, Nitrogen adsorption–desorption, SEM and Py-FTIR techniques. Catalytic tests showed that the MZS-5 composite catalyst exhibited higher catalytic activity compared with the conventional microporous ZSM-5, SAPO-5 zeolite and mesoporous Al-MCM-41 molecular sieve for catalytic cracking of 1,3,5-triisopropylbenzene (TIPB). The remarkable catalytic reactivity of TIPB molecules was mainly attributed to the presence of the hierarchical zeolite structure. In the MZS-5 structure, the mesopores provided pathways for transportation of larger molecules and the microporous ZSM-5 and SAPO-5 zeolite provided acidic sites for catalytic activity.     

Kennzeichnende Verfahrens- und Einflußgrößen beim katalytischen Fließbett-Cracken

Characteristic process parameters and variables in catalytic fluidized bed cracking . Catalytic fluidized-bed cracking occupies a distinctive position among the various conversion processes. With regard to its favorable product range, the process is characterized by low processing costs coupled with flexibility of raw materials. A number of independent process parameters are available for control of the reactions involved in catalytic cracking and for influencing the product range. The cracking reactions taking place and the interplay of the independent and dependent variables are described. Apart from the actual cracking process, particular importance attaches to the regeneration of the catalyst charged with coke since it has a decisive influence on the thermal economy of the plant. Depending upon the desired product yield or the raw materials a suitable catalyst must be chosen. Considerable progress has recently been made in catalyst development.     

CDOS催化剂的重油裂化性能

通过对某炼油厂减四线油和减四线抽出油的性能对比,选择更难裂化的减四线抽出油在小型固定流化床装置上,对以DOSY为活性组元的CDOS催化剂和常规REY重油裂化降烯烃催化剂进行对比实验,考察已工业应用的CDOS催化剂在实验室条件下,对催化剂的重油转化及降烯烃的能力。结果表明,在相同剂油比下,CDOS催化剂作催化材料时,具有更好的产物分布,可获得较高的转化率和轻质油收率以及较低的焦炭和重油收率。CDOS催化剂降低汽油中烯烃的能力高于常规REY类型重油裂化降烯烃催化剂。     

In situ synthesis, characterization and catalytic activity of ZSM-5 zeolites on kaolin microspheres from amine-free system

ZSM-5 zeolites were synthesized by an in situ hydrothermal crystallization method on kaolin microspheres from an organic template-free solution. The as-synthesized samples were characterized by using X-ray diffraction, scanning electron microscopy, Fourier Transform Infrared spectrometry, N₂ adsorption and desorption, and Temperature Programmed Desorption. The results showed that small-sized ZSM-5 crystallites with less than 1 micron in diameter were effectively formed on kaolin microspheres. The synthesized products indicated high hydrothermal stability and strong acidity. By mixing the H-type ZSM-5/CMK composite with a Fluid Catalytic Cracking base catalyst, the performance of the catalyst is then evaluated. The results of catalytic performance evaluation showed that with the addition of ZSM-5/CKM, it favored the production of light olefins such as propylene and butylenes by catalytic cracking of vacuum gas oil.     

稠油水热催化裂解机理的研究进展

在论述了催化裂解开采稠油对能源保证的重要性意义上,从催化水热裂解的理论机理研究方面对水热裂解催化降黏方法进行了全面介绍。对稠油水热裂解发生涉及的催化裂解化学反应及其机理作了分析讨论。同时对近年来的主要研究使用的三类催化剂做了重点介绍,着重分析了其催化降黏机理。     

重油催化裂化工艺的新进展

介绍了重油催化裂化工艺的新进展,如毫秒催化裂化工艺、下行床反应器催化裂化工艺、两段提升管催化裂化工艺、多产轻质烯烃的催化裂化新工艺、催化裂化汽油改质降烯烃新工艺等,并对重油催化裂化工艺的发展趋势进行了展望。     

Kinetics and selectivity of reactions of 1-alkenes on HY zeolite: The influence of chain length

Catalytic reactions of 1-alkenes on HY have been studied at 400°C. Skeletal isomerization to the corresponding rnonornethylalkene is the dominant initial process. Cracking and coke formation are also observed as initial processes. Initial cracking selectivity can be accounted for by monomolecular β-scission processes involving a carbenium ion intermediate. However, the initial cracking product distribution for l-hexene must be explained by assuming some contribution from a dimerization-cracking mechanism. The kinetics of these processes have been fitted by a model previously used to describe the reactions of n-alkanes. It is found that the rate constants for both skeletal isomerization and cracking increase with chain length of the feed alkene.     

石油加工中的催化裂化技术分析

现代石油加工工业的技术发展中,催化加工工艺的重要性越来越明显。催化加工对原料具有更好的适应能力,产品也具有清洁纯净和耗能较低的特点。文章分析了影响石油加工中催化裂化的影响因素,分析了反应一再生装置的技术不同特点和催化剂的发展过程,提出了石油加工催化裂化的发展目标。     

催化裂解制低碳烯烃技术研究进展

对以石油路线生产低碳烯烃的催化裂解工艺进行了综述。催化裂解结合了传统蒸汽裂解和流化催化裂化的优势,表现出良好的原料适应性和较高的低碳烯烃产率,针对不同的石油裂解原料已经开展了相应工艺技术的研究。本文总结了目前催化裂解制低碳烯烃技术的研究进展,指出ZSM-5分子筛催化剂、热力学平衡限制和动力学反应条件是催化裂解反应过程中的重要影响因素和研究内容。催化剂研究仍是催化裂解工艺开发的重点,而热力学和动力学是研究反应规律的有效方法,这是今后实现石油烃类定向转化的研究方向。