Application of New Heavy Metals Resistant Porous Binder Material Used in Fluid Catalytic Cracking Reaction

A novel porous binder was obtained from acid-treated kaolin. This new binder possessed abundant meso/macropores, good hydrothermal stability and heavy metal resistance. The prepared catalyst using new binder featured low attrition index and large pore volume. The catalysts were contaminated with Ni, V, and tested in a fixed-fluidized bed reactor unit. In comparison with the reference sample, the oil conversion achieved by the above-mentioned catalyst increased by 3.50 percentage points, and heavy oil yield decreased by 2.86 percentage points, while the total liquid yield and light oil yield increased by 2.82 percentage points and 0.79 percentage points, respectively. The perfect pore structure, good hydrothermal stability and heavy metal resistant performance of new binder were the possible causes leading to its outstanding performance.

Numerical Predication of Cracking Reaction of Particle Clusters in Fluid Catalytic Cracking Riser Reactors

Behavior of catalytic cracking reactions of particle cluster in fluid catalytic cracking （FCC） riser reactors was numerically analyzed using a four-lump mathematical model. Effects of the cluster porosity, inlet gas velocity and temperature, and coke deposition on cracking reactions of the cluster were investigated. Distributions of temperature, gases, and gasoline from both catalyst particle cluster and an isolated catalyst particle are presented. The reaction rates from vacuum gas oil （VGO） to gasoline, gas and coke of individual particle in the cluster are higher than those of the isolated particle, but it reverses for the reaction rates from gasoline to gas and coke. Less gasoline is produced by particle clustering. Simulated results show that the produced mass fluxes of gas and gasoline increase with the operating temperature and molar concentration of VGO, and decrease due to the formation of coke.

Fluid Catalytic Cracking Technology for Maximum Gasoline Production

Increasing gasoline production in FCC unit can improve the utilization efficiency of petroleum resources and gain economic benefit.This paper discusses the technical principles for increasing FCC gasoline yield from the aspects of feedstock properties,operating conditions,LCO(light cycle oil)recycling,catalyst selection and reactor type,and illustrates the industrial application examples for maximizing gasoline production.The technical measures,such as optimizing the feedstock,properly increasing the catalyst activity and reaction temperature,recycling LCO or hydrotreated LCO,applying high gasoline yield catalyst,and adopting the two-zone riser reactor,are proposed to enhance the gasoline yield.

In-situ Synthesis and Catalytic Properties of ZSM-5/Rectorite Composites as Propylene Boosting Additive in Fluid Catalytic Cracking Process

Using rectorite extrudates from calcined rectorite powder as the starting material, a series of ZSM-5/rectorite composites were prepared via the in-situ crystallization method. The physicochemical properties and propylene boosting performance of the resulting samples were characterized by using X-ray diffraction, scan- ning electronic microscopy/energy dispersive spectrometer, N2 adsorption-desorption, and Fourier transformed in/tared spectroscopy of pyndine adsorption, respectively, and assessed by using Daqing atmospheric residue as Iced- stock. The results showed that the ZSM-5/rectorite composites in which the ZSM-5 phase grows inositu as a 2-3 p,m thick layer on rectorite particles have a trimodal microporous-mesoporous-macroporous structure and thus exhibit outstanding propylene boosting performance. Compared with a commercial ZSM-5 incorporated fluid catalytic cracking catalyst, the ZSM-5/rectorite composite incorporated catalyst increased the yield and selectivity of propylene by 2.44% and 5.35%, respectively.

Decoupling Control of Fluid Catalytic Cracking Unit

This study presents a decoupling control scheme of fluid catalytic cracking unit to account for the high interaction between two temperature control loops. The feed flow rate load disturbance is introduced to test the proposed decoupling control scheme. Through simulation study shown that the decoupling is effective, stable and it presents advantage over controller without decoupler. Also, this scheme is able to offer good dynamic performance for most disturbances.

Distribution and State of Ni Contaminants on Resid Fluid Catalytic Cracking Catalysts—Characterization by AEM, EPMA, UV-Vis and TPR

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Study of Carbon Nanotube Supported Co-Mo Selective Hydrodesulphurization Catalysts for Fluid Catalytic Cracking Gasoline

In this paper, carbon nanotube supported Co-Mo catalysts for selective hydrodesulphurization （HDS） of fluid catalytic cracking （FCC） gasoline were studied, using di-isobutylene, cyclohexene, 1-octene and thiophene as model compounds to simulate FCC gasoline. The results show that the Co-Mo/CNT has very high HDS activity and HDS/hydrogenation selectivity comparing with the Co-Mo/γ-Al2O3 and Co-Mo/AC catalyst systems. The saturation ratio of cyclohexene was lower than 50%, and the saturation ratio of 1,3-di-isobutylene lower than 60% for the Co-Mo/CNT catalysts. Co/Mo atomic ratio was found to be one of the most important key factors in influencing the hydrogenation selectivity and HDS activity, and the most suitable Co/Mo atomic ratio was 0.4. Co/CNT and Mo/CNT mono-metallic catalysts showed lower HDS activity and selectivity than the Co-Mo/CNT bi-metallic catalysts.

MAGNETIC SEPARATION OF FLUID CATALYTIC CRACKING EQUILIBRIUM CATALYST

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Failure analysis of corrosion cracking and simulated testing for a fluid catalytic cracking unit

The failure of a fluid catalysis and cracking unit (FCCU) in a Chinese refinery was investigated by using nondestructive detection methods, fracture surface examination, hardness measurement, chemical composition and corrosion products analysis. The results showed that the failure was caused by the dew point nitrate stress corrosion cracking. For a long operation period, the wall temperature of the regenerator in the FCCU was below the fume dew point. As a result, an acid fume NOx-SOx-H2O medium present- ed on the surface, resulting in stress corrosion cracking of the component with high residual stress. In order to confirm the relative conclusion, simulated testing was conducted in laboratory, and the results showed similar cracking characteristics. Finally, some sug- gestions have been made to prevent the stress corrosion cracking of an FCCU from re-occurring in the future.

Industrial Application and Fundamental Research Progress on Fluid Catalytic Cracking Technology of Downer Reactors

Fluid catalytic cracking(FCC)technologies of downer reactors,which have reached the demonstration or commercial scale,are systematically discussed,i.e.,millisecond catalytic cracking,fluidization lab of Tsinghua University,and high-severity FCC.Moreover,aiming to promote industrial application,the fundamental studies are comprehensively described,particularly focusing on high-density downer reactors,clusters,and up-scaling.Furthermore,from the perspective of industrial application,some research directions toward further developments are suggested.

Modeling and Optimization of a Fractionation,Absorption,and Stabilization System in an Industrial Fluid Catalytic Cracking Process

Fluid catalytic cracking(FCC)is a vitally important refinery process.The fractionation,absorption,and stabilization system in the FCC process is a significant way to obtain key products,and its parameters will directly affect the quality of the products.In this work,using industrial data from an actual FCC process,a model of the FCC fractionation,absorption,and stabilization system was developed using process simulation software.The sequence quadratic program algorithm was then used to identify the parameters of each tower,increasing the accuracy of the simulation results.Next,using this improved model,a sensitivity analysis was performed to examine the effects of different operating conditions.The pattern-search method was then used to optimize the operating parameters of the system.The results showed that the optimized model has good prediction accuracy,and using the model,it was found that changing the operation parameters could result in a 1.84%improvement in economic benefits.As such,the developed model was demonstrated to be usefully applicable to the optimization of the process operation of an FCC fractionation,absorption,and stabilization system.

A new generic reaction for modeling fluid catalytic cracking risers

A new generic reaction in the form of PC_i→PC_m+[i,m]→PC_m+λi,m coke+surplusage has been proposed for describing the catalytic cracking behavior of petroleum narrow cuts or pseudo-components(PCs),where the rate constant formula is derived from the transition state theory and the coking amount is correlated to the properties of the intermediate substance [i,m].In composing the cracking reaction network for feedstock and product oils,only the product PC m of the proposed generic reaction is used,which together with a criterion for excluding exothermic reactions,distinctly reduces the number of reactions in the network.With the proposed cracking reaction scheme coupled with special pseudo-components,a predictive one-dimensional steady state model for fluid catalytic cracking risers is formulated in the sense that for a given riser and given catalyst,the model parameters are independent of stock oils,product schemes and other operational conditions.The great correlating and predicting capability of the resulted model is tested with production data in different scenarios of four commercial risers.

Catalytic cracking of light diesel over Au/ZSM-5 catalyst for increasing propylene production

The catalytic cracking of light diesel oil （235–337 ＆#176;C） over gold‐modified ZSM‐5 was investigated in a small confined fluidized bed at 460 ＆#176;C and ambient pressure. Different Au/ZSM‐5 catalysts were prepared by a modified deposition‐precipitation method by changing the preparation procedure and the amount of gold loading and were characterized by X‐ray diffraction, N2 adsorp‐tion‐desorption, temperature‐programmed desorption of NH3, transmission electron microscopy and inductively coupled plasma spectrometer. It was found that a small amount of gold had a posi‐tive effect on the catalytic cracking of light diesel oil and increased propylene production at a rela‐tively low temperature. The maintenance of the ZSM‐5 MFI structure, pore size distribution and the density of weak and strong acid sites of the Au/ZSM‐5 catalysts depended on the preparation pa‐rameters and the Au loading. Simultaneous enhancement of the micro‐activity and propylene pro‐duction relies on a synergy between the pore size distribution and the relative intensity of the weak and strong acid sites. A significant improvement in the micro‐activity index with an increase of 4.5 units and in the propylene selectivity with an increase of 23.2 units was obtained over the Au/ZSM‐5 catalyst with an actual Au loading of 0.17 wt%.

Effects of Temperature and Catalyst to Oil Weight Ratio on the Catalytic Conversion of Heavy Oil to Propylene Using ZSM-5 and USY Catalysts

It is useful for practical operation to study the rules of production of propylene by the catalytic conversion of heavy oil in FCC （fluid catalytic cracking）. The effects of temperature and C/O ratio （catalyst to oil weight ratio） on the distribution of the product and the yield of propylene were investigated on a micro reactor unit with two model catalysts, namely ZSM-5/Al2O3 and USY/Al2O3, and Fushun vacuum gas oil （VGO） was used as the feedstock. The conversion of heavy oil over ZSM-5 catalyst can be comparable to that of USY catalyst at high temperature and high C/O ratio. The rate of conversion of heavy oil using the ZSM-5 equilibrium catalyst is lower compared with the USY equilibrium catalyst under the general FCC conditions and this can be attributed to the poor steam ability of the ZSM-5 equilibrium catalyst. The difference in pore topologies of USY and ZSM-5 is the reason why the principal products for the above two catalysts is different, namely gasoline and liquid petroleum gas （LPG）, repspectively. So the LPG selectivity, especially the propylene selectivity, may decline if USY is added into the FCC catalyst for maximizing the production of propylene. Increasing the C/O ratio is the most economical method for the increase of LPG yield than the increase of the temperature of the two model catalysts, because the loss of light oil is less in the former case. There is an inverse correlation between HTC （hydrogen transfer coefficient） and the yield of propylene, and restricting the hydrogen transfer reaction is the more important measure in increasing the yield of propylene of the ZSM-5 catalyst. The ethylene yield of ZSM-5/A1203 is higher, but the gaseous side products with low value are not enhanced when ZSM-5 catalyst is used. Moreover, for LPG and the end products, dry gas and coke, their ranges of reaction conditions to which their yields are dependent are different, and that of end products is more severe than that of LPG. So it is clear that maximizing LPG and propylene and restricting dry gas and coke can be both achieved via increasing the severity of reaction conditions among the range of reaction conditions which LPG yield is sensitive to.

Studies on the preliminary cracking: The reasons why matrix catalytic function is indispensable for the catalytic cracking of feed with large molecular size

The matrix catalytic function when cracking the feed oil with large molecular size was systematically studied using three different catalyst configurations, including staged bed, partly mixed bed and completely mixed bed. Results showed that molecules in the feed oil with large molecular size indeed preferred to be first precracked on the matrix surface and then entered into the zeolite pores during the practical reaction process. Furthermore, the matrix catalytic function exhibited a great matrix-precracking ability to large feed molecules, which considerably increased the catalyst activity and the light oil selectivity. Besides the much better accessibility, the matrix-precracking ability was also from the similar capability to crack large feed hydrocarbons into the moderate fragments with that of the zeolite component. More interestingly, the interactions between the matrix catalytic function and the zeolite catalytic function made the catalyst not only exhibit much more catalytic advantages of the zeolite component, but also retain the matrix-precracking ability. As a result, the interactions enhanced the catalyst activity and improved the product distribution at the same time. The matrix catalytic function is indispensable for the catalytic cracking of feed with large molecular size, although the matrix component itself presented an inferior catalytic performance than the zeolite component did. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

Synthesis of mesoporous high‐silica zeolite Y and their catalytic cracking performance

Mesoporous high‐silica zeolite Y with advantages of improved accessibility of acid sites and mass transport properties is highly desired catalytic materials for oil refinery,fine chemistry and emerg‐ing biorefinery.Here,we report the direct synthesis of mesoporous high‐silica zeolite Y(named MSY,SiO_(2)/Al2O_(3)≥9.8)and their excellent catalytic cracking performance.The obtained MSY mate‐rials are mesoporous single crystals with octahedral morphology,abundant mesoporosity and ex‐cellent(hydro)thermal stability.Both the acid concentration and acid strength of H‐form MSY are obviously higher than those of commercial ultra‐stable Y(USY),which should be attributed to the uniform Al distribution of MSY zeolite.The H‐MSY displays an obviously reduced deactivation rate and improved catalytic activity in the cracking reaction of bulky 1,3,5‐triisopropylbenzene(TIPB),as compared with its mesoporogen‐free counterpart and USY.In addition,H‐MSY was investigated as catalyst for the cracking of industrial heavy oil.The MSY‐based catalyst(after aging at 800 oC in 100%steam for 17 h)exhibits superior conversion(7.64%increase)and gasoline yield(16.37%increase)than industrial fluid catalytic cracking(FCC)catalyst under the investigated conditions.

Effects of Metal Oxide in ZSM-5 Zeolite on Its Catalytic Performance in FCC Process

Effects of metal oxide in ZSM-5 zeolite on its catalytic performance in fluid catalytic cracking reaction were studied via characterization by XRD and FT-IR spectroscopy using pyridine and collidine as molecular probes,and the modified ZSM-5 zeolite was evaluated in a micro reactor using standard light diesel fraction as the feedstock.Test results indicate that the metal species introduced into the ZSM-5 zeolite had led to the formation of Lewis acid centers.When the modified ZSM-5 zeolite with the metal species on its surface was used as the catalyst in FCC reaction,both the propylene yield and the propylene concentration in the liquefied petroleum gas increased,but in the meantime,more hydrogen and coke were formed at high conversion rate under the joint action of nonselective cracking of Lewis acid centers and dehydrogenation at metal centers on its outside surface.

Mechanistic Insights into the Catalytic Cracking of Cyclohexane

Although naphthenes have long been identified as important feedstock components for the production of light olefins and aromatics in fluid catalytic cracking units,their cacking mechanism and microscopic reaction networks,such as activation modes,ring-opening paths,and the production of aromatics,remain debated.In this context,we reported experimental and computational work aimed at elucidating the reaction network of naphthenes in fluid catalytic cracking using cyclohexane as the model naphthene.First,the main reactions for the formation of highly selective and value-added products such as light olefins and aromatics were discussed.Then,the proportions of cyclohexane activation via(i)the non-classical carbonium mechanism and(ii)the classical carbenium mechanism were analyzed by data fitting methods,which revealed that around 32.6%of cyclohexane was initiated by path(i),and the remaining naphthene was activated by path(ii).Moreover,our DFT results showed that the ring opening of cyclohexane through pathway(i)was more difficult than that through path(ii),and ring opening followed by the ring contraction of cyclohexane carbenium ions was the most energetically favorable route among the different ring-opening ways.

Study on Mechanism for Formation of Carbon Oxides During Catalytic Cracking of High Acidic Crude

Based on the basis of analysis and interpretation of the products distribution of catalytic cracking of high acidic crude, the mechanism for decarboxylation of petroleum acids during FCC process was discussed. The protons originated from the Bronsted acid sites can combine with oxygen of the carbonyl groups with more negative charges to form reaction intermediates that can be subjected to cleavage at the weak bonds, leading to breaking of carboxylic groups from the carboxylic acids followed by its decomposition to form alkyl three-coordinated carbenium ions, CO and H2O. The Lewis acid as an electrophilic reagent can abstract carboxylic groups from carboxylic acids to subsequently release CO2.

A generalized CFD model for evaluating catalytic separation process in structured porous materials

A hybrid multiphase model is developed to simulate the simultaneous momentum, heat and mass transfer and heterogeneous catalyzed reaction in structured catalytic porous materials. The approach relies on the combination of the volume of fluid(VOF) and Eulerian–Eulerian models, and several plug-in field functions. The VOF method is used to capture the gas–liquid interface motion, and the Eulerian–Eulerian framework solves the temperature and chemical species concentration equations for each phase.The self-defined field functions utilize a single-domain approach to overcome convergence difficulty when applying the hybrid multiphase for a multi-domain problem. The method is then applied to investigate selective removal of specific species in multicomponent reactive evaporation process. The results show that the coupling of catalytic reaction and interface species mass transfer at the phase interface is conditional, and the coupling of catalytic reaction and momentum transfer across fluid–porous interface significantly affects the conversion rate of reactants. Based on the numerical results, a strategy is proposed for matching solid catalyst with operating condition in catalytic distillation application.