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C2+ hydrocarbons, especially C2+ olefins, as important basic chemical raw materials, mainly come from petroleum cracking. With the increasing scarcity of petroleum resources, the search for new olefins production routes has become the focus of research, and the production of olefins by the oxidative coupling of methane (OCM) process has attracted extensive attention. The OCM route is an important alternative to the production of olefins from petroleum resources and is also an important direction for the development of efficient and clean utilization of natural gas. In this paper, the mechanism, catalysts, and other key factors for the production of olefins by methane oxidative coupling are reviewed. The mechanism of OCM, including the reaction pathway and the formation of intermediate products, is introduced. Then, commonly used catalysts, such as alkali metal/alkaline earth metal oxides, rare earth metal oxides, composite metal oxides with special structures, and classical catalysts Mn/Na2WO4/SiO2, and their mechanisms of action in the reaction are discussed. In addition, the application of chemical looping oxidative coupling of methane (CLOCM) in olefin production is also investigated, which is a promising alternative way due to the high selectivity of olefins and the low cost of catalysts owing to the excellent performance of the catalyst recycling. These studies will help to further understand the mechanism of OCM for olefin production and provide guidance and support for applications in related fields. [ABSTRACT FROM AUTHOR]

Highlights • A new six-lump kinetics scheme was developed. • New six-lump activation energies, frequency factors and heat of reactions developed. • The estimated parameters can be used to simulate any type of FCC riser. Abstract In this work a simulation of detailed steady state model of an industrial fluid catalytic cracking (FCC) unit with a newly proposed six-lumped kinetic model which cracks gas oil into diesel, gasoline, liquefied petroleum gas (LPG), dry gas and coke. Frequency factors, activation energies and heats of reaction for the catalytic cracking kinetics and a number of model parameters were estimated using a model based parameter estimation technique along with data from an industrial FCC unit in Sudan. The estimated parameters were used to predict the major riser fractions; diesel as 0.1842 kg-lump/kg-feed with a 0.81% error while gasoline as 0.4863 kg-lump/kg-feed with a 2.71% error compared with the plant data. Thus, with good confidence, the developed kinetic model is able to simulate any type of FCC riser with six-lump model as catalyst-to-oil (C/O) ratios were varied and the results predicted the typical riser profiles. [ABSTRACT FROM AUTHOR]

Data are given on the cracking of vacuum gas oil with HY zeolite catalysts on aluminum pillared natural calcium montmorillonite under vigorous cracking conditions in laboratory reactors of different volumes with a fixed catalyst bed at 500-600°C. Increasing the cracking temperature and contact time of the vacuum gas oil with the catalyst was shown to increase the yield of the gas phase. The greatest gas yield was 42%. In this case, the gas contained C2 - C4 alkenes, including 28% propylene. We concluded that it should be possible to use aluminum pillared calcium montmorillonite as a component of a zeolite cracking catalyst for petrochemical processes. [ABSTRACT FROM AUTHOR]

Additives to a zeolite-containing cracking catalyst were synthesized and studied in order to enhance the resistance to the poisoning effect of nitrogen compounds (in particular indole) upon cracking of n-undecane as the model FCC hydrocarbon. The additives were represented by acid-activated clays and mixed oxides. The activation of clays in the catalyst by 5% sulfuric acid solutions was shown to enhance the resistance to nitrogen. The introduction of Mg, Al – mixed oxides in the catalytic system in the amount of 10 wt% increased its activity and resistance to indole. The highest resistance was observed for the systems containing magnesium‑aluminum oxides with a Me 2 + to Me 3 + molar ratio equal to 0.5: 1. Cobalt modification of these mixed oxides enhanced the activity and nitrogen resistance of the cracking catalysts. Use of such nitrogen-resistant catalysts will allow cracking of heavy raw materials. [ABSTRACT FROM AUTHOR]

This work aims to investigate the importance of biomass char and the metal oxides in the ash in tar cracking during the volatile-char interactions. Experiments were carried out in a two-stage fixed reactor, and corncob, one typical agricultural biomass rich in potassium, was chosen as raw material. Results showed that char and char-supported potassium catalysts have good activity for tar elimination due to the good absorbability of char and catalytic property of potassium. In particular, tar conversion efficiency can reach 95.8% by using 1.5 K-char catalyst at 700 °C. The reforming reactions can be significantly enhanced during the volatile-char interactions in the presence of char and char-supported potassium catalysts. As a result, the syngas yield increased significantly with increasing temperature and supported K, particularly the combustible gases including H, CO and CH. Physical and chemical structure of char changed due to reforming reactions related to the carbon, while the content of potassium was almost unchanged. [ABSTRACT FROM AUTHOR]

Vacuum residue cracking has been successfully conducted under supercritical water condition in presence of various metal oxide nanocalysts, namely NiO, CuO, ZnO, Co 2 O 3 , and Cr 2 O 3 synthesized at supercritical water. The cracking experiments were carried out at 450 °C. Three species of cracking: maltene, asphaltene, and coke were then weighed and their corresponding speciation was defined. Gas chromatography-mass spectrometry (GC–MS), nuclear magnetic resonance spectroscopy (NMR), thermogravimetric analysis (TGA), and elemental analysis (CHNS) tests were utilized to prove the performance of upgrading reactions. It was revealed that NiO showed the best performance among other catalyst, in which its activity and stability in catalytic cracking changed slightly. According to the results obtained from GC–MS, NMR, TGA, and CHNS anlyses, it was confirmed that the proportion of heavy hydrocarbons of products (i.e. non-catalytic and catalytic reactions) was lower than that of feedstock. [ABSTRACT FROM AUTHOR]

A molecular-level-process model for a fluidized catalytic cracking process was developed. The work was aimed at the coarseness of the reaction network used in traditional lumping kinetic models. A feed-component matrix containing 14692 molecules was generated using a structure-oriented-lumping (SOL) method. A total of 95 groups of reaction rules were compiled, and 702943 reactions were involved. The SOL reaction kinetic model was combined with the reactor model to calculate the temperature distribution and feedback on the complex reaction network by taking into account the reaction heats in each reaction. The model was validated by the industrial data and predicted that the gasoline yield was >51% and the olefin content in gasoline was <24% at proper operation temperatures and catalyst/oil ratios. With the aid of the molecular-level model for the maximizing-isoparaffin technology, the product distribution and corresponding product quality can be controlled rationally by manipulating the operation conditions. [ABSTRACT FROM AUTHOR]

Catalytic and thermal cracking of polypropylene was performed in a batch reactor. Effect of hydrochloric acid activation on kaolin clay, effects of catalysts (acid-activated clays), promoter (5 wt% Ni), and cracking temperatures on the liquid oil yield were investigated. Results show optimized liquid yield (71.9%) obtained at 470°C with kaolin clay activated with 3 M HCl. Acid-activated catalysts were analyzed using XRD and the results reveal the reduction in peaks’ intensities. Weight loss of polypropylene was investigated by thermogravimetric analysis. FTIR and GCMS techniques were employed to analyze the liquid products. [ABSTRACT FROM PUBLISHER]

The problem of prompt speed and density profile mapping based on mathematical modeling of particle motion in the acceleration section of catalyst pneumotransport lines is discussed. An algorithm is developed to calculate the distribution of these parameters along the longitudinal coordinate of reactor-lifts to improve ergonomic efficiency of operation of reaction-regeneration systems used in oil refining and petrochemical industries. [ABSTRACT FROM AUTHOR]

The mechanism of hydrogen transfers from naphthenes (methylcyclohexane, cyclohexane) or their deuterated derivatives to 1-hexene was specified over model acid zeolite catalysts (HREY or HZSM5). The composition of products is determined by two reactions-cracking and intermolecular hydrogen transfer. The monomolecular cracking reaction proceeds mostly on HZSM-5 zeolite, whereas the bimolecular hydrogen transfer reactions are catalyzed by the wide-pore HREY zeolite. It was found that during the hydrogen transfer from the naphthene molecule (hydrogen donor) to the olefin molecule (hydrogen acceptor) only one hydrogen atom is transferred, whereas the second hydrogen atom comes from the Brønsted acid site of the catalyst. [ABSTRACT FROM AUTHOR]

The catalytic cracking of a blend of raw bio-oil (20 wt %) from black poplar sawdust fast pyrolysis and vacuum gasoil (VGO, 80 wt %) has been studied. The runs have been performed in a riser simulator reactor (RSR) under fluid catalytic cracking (FCC) conditions; that is, 500-560 °C, catalyst tofeed mass ratio of 6 gcat (gfeed)-1 on a dry basis, reaction times of 3-10 s and a equilibrated commercial FCC catalyst. The cofeeding effect has been quantified by comparing the yields of product lumps and individual components in the gaseous fraction and gasoline lump in the cracking of VGO, raw bio-oil, and their blend (20% bio-oil/80% VGO), at the same conversion values (60-70 wt %). The cofeeding has a favorable synergy because it promotes the formation of C3-C4 and gasoline (C5-C12) hydrocarbon lumps, attenuating the formation of CO2, CO, and also coke formation. In the cracking of the blend (80% VGO/20% bio-oil) at 70 wt % conversion, a deoxygenation degree of 95 wt % has been obtained, with a total liquid fuel yield of 52.8 wt % and a gasoline yield of 31.6 wt %, with a low oxygenate fraction (<4 wt %) containing carboxylic acids, aldehydes, ketones, and phenols. [ABSTRACT FROM AUTHOR]

Cracking–Deoxygenation process is one of the important reaction pathways for the production of biofuel with desirable n- C 17 hydrocarbon chain via removal of oxygen compounds. Calcium-based catalyst has attracted much attention in deoxygenation process due its relatively high capacity in removing oxygenated compounds in the form of CO 2 and CO under decarboxylation and decarbonylation reaction, respectively. In the present study, deoxygenation of triolein was investigated using Ca(OH) 2 nanocatalyst derived from low cost natural waste shells. The Ca(OH) 2 nanocatalyst was prepared via integration techniques between surfactant treatment (anionic and non-ionic) and wet sonochemical effect. Results showed that sonochemically assisted surfactant treatment has successfully enhanced the physicochemical properties of Ca(OH) 2 nanocatalyst in terms of nano-particle sizes (∼50 nm), high surface area (∼130 m 2 g−1), large porosity (∼18.6 nm) and strong basic strength. The presence of superior properties from surfactant treated Ca(OH) 2 nanocatalysts rendered high deoxygenation degree, which are capable of producing high alkane and alkene selectivity in chain length of n-C 17 (high value of C 17 /( n -C 17 + n -C 18 ) ratio = 0.88). Furthermore, both Ca(OH) 2 –EG and Ca(OH) 2 –CTAB nanocatalysts showed high reactivity with 47.37% and 44.50%, respectively in total liquid hydrocarbon content of triolein conversion with high H/C and low O/C ratio. [ABSTRACT FROM AUTHOR]

To improve the selectivity performance of CoMoS catalysts applied to the hydrodesulfurization (HDS) of fluid catalytic cracking (FCC) gasoline, a series of CoMoS/Al 2 O 3 catalysts was prepared with alumina of different pore structures, and their HDS performance was evaluated with a real FCC gasoline. This study indicated that CoMoS/Al 2 O 3 catalysts prepared with micro- or meso-porous alumina possessed high HDS activity but low selectivity, whereas macro-porous alumina enhanced the selectivity of CoMoS catalysts. The enhanced HDS selectivity was due to the tuning of the MoS 2 slabs and the weakening of the internal diffusion resistance. Based on the above results, the optimal CoMoS/Al 2 O 3 catalyst was prepared with the alumina of the tri-modal pore distribution at approximately 5–8 nm, 15–20 nm, and 90–100 nm. The optimal catalyst displayed a balanced HDS activity and selectivity in contrast to the reference catalyst prepared with K- and P-modified Al 2 O 3 . [ABSTRACT FROM AUTHOR]

Jatropha oil was cracked over micoporous catalysts, such as HY, HZSM-5, and HMordenite, at the optimized conditions obtained over Hβ towards cracking of jatropha oil. The synthesized catalysts were characterized by X-ray diffraction, Brunauer-Emmett-Teller surface area analyzer, inductively coupled plasma, and temperature programmed desorption techniques. Among the microporous materials, HZSM-5 catalyst was found to be the best in terms of conversion (62%), selectivity towards green gasoline (50%), and less coke formation (0.8%) in the cracking of jatropha oil. Cracking of other oils, such as castor, neem, and pongamia, under the optimized conditions resulted in 82% conversion of castor oil; however, higher selectivity towards green gasoline (49%) was obtained in the cracking of pongamia oil. [ABSTRACT FROM PUBLISHER]

The article shows the results of thermal cracking of natural bitumen of Kazakhstan's two deposits. The variation of the chemical and the fractional composition of the cracking products are determined depending on the process conditions. A comparative analysis of the influence of the catalyst is carried out to composition of natural bitumen. [ABSTRACT FROM AUTHOR]

Mesopore-modified mordenite zeolitic materials with different Si/Al ratios have been prepared and tested in the biomass pyrolysis and catalytic cracking of vacuum gasoil. Alkaline treatment was carried out to generate mesoporosity. Severity of alkaline treatment was found to be of paramount importance to tune the generated mesoporosity, while it significantly affected the crystallinity of treated mordenites. It was moreover observed that the alkaline treatment selectively extracted Si decreasing the Si/Al ratio of treated samples. Catalytic activity of parent and alkaline treated mordenites was studied in the pyrolysis of biomass. All zeolitic based materials produced less amounts of bio-oil but of better quality (lowering the oxygen content from ∼40% to as much as 21%) as compared to the non-catalytic pyrolysis experiments. On the other hand, it was found that the combination of mesopore formation and high surface area after alkaline treatment of the mordenite with a high Si/Al ratio resulted in the enhancement of its catalytic activity, despite the reduction of its acidity. The increment of the decarboxylation and dehydration reactions, combined with a reduction of carbon deposition on the catalyst, resulted in a remarkable decrease in the oxygen content in the organic fraction and therefore, resulted in a superior quality liquid product. Alkaline treated mordenites were additionally acid treated targeting dealumination and removal of the extra framework debris, thus generating mesopore-modified mordenite samples with stronger acid sites and higher total acidity, as candidate catalysts for catalytic cracking of vacuum gasoil. Desilicated and especially desilicated and dealuminated mordenites exhibited the highest activity and selectivity towards LCO with the best olefinicity in gases and higher bottoms conversion. Therefore, an optimized desilicated–dealuminated mordenite additive could be an interesting candidate as a component of the FCC catalyst for a high LCO yield. [ABSTRACT FROM AUTHOR]

Influence of the combined use of catalytic cracking catalyst and milled glass waste on the properties of building ceramics (density, compressive strength, water absorption, frost resistance) is analysed in the paper. The research showed that under the 1050°C temperature firing regime, catalyst waste decreases density, compressive strength and frost resistance of ceramic samples, while milled glass increases the values of these parameters. The formation mix without milled glass and with 20 % of catalyst waste had the following values of physical-mechanical properties: density 1590kg/m³, compressive strength 17.5 MPa, frost resistance 195 cycles, and water absorption about 18.0%. The formation mix without catalyst waste and with 20 % of milled glass had the values of density 1790 kg/m³, compressive strength 29.2 MPa, frost resistance more than 300 cycles, and water absorption 12.6 %. Firing samples at 1080°C temperature, the largest values of density (1980kg/m³), compressive strength (36.1 MPa) and frost resistance (>300 cycles according to LST 1985:2006, unilateral method) were obtained for the formation mix containing the combination of 10 % of catalyst waste and 10 % of milled glass. [ABSTRACT FROM AUTHOR]

Abstract: In situ growth of ZSM-5 crystals on the surface of Ni-based alloy supports by hydrothermal synthesis and their mechanical, structural stability were investigated. ZSM-5 crystals grown on the wall of a long (750mm) tubular reactor with a small inner diameter (1mm) was evaluated as a structured catalyst for cracking of n-heptane as a model endothermic fuel. The results have shown that the adhesion strength between ZSM-5 crystals and the support was strong enough to resist a heating/fast-cooling cycle (the sample was immersed into water immediately after being heated to be 750°C). The crystalline structure of ZSM-5 crystals was also stable against the heating/fast-cooling cycle. The structured catalyst was shown to be catalytically active for cracking of n-heptane (LHSV=200h−1) at 700°C. The formation rates of gaseous cracking products were 9.8mlmin−1 and 29.3mlmin−1 for the bare tubular reactor and the tubular reactor with ZSM-5 crystals grown on the wall, respectively. These structured catalysts show high promise for cracking of endothermic fuels at high temperatures. [Copyright &y& Elsevier]

Abstract: An assessment of the process conditions for the isomerization–cracking of long-chain n-paraffins over commercial Pt/SO4 2––ZrO2 catalysts was made. Pretreatment and reaction conditions were optimized with a focus on the maximization of the yield of short, high octane branched paraffins for the gasoline pool. While selectivity was an important issue attention was also paid to the reduction of the yield to gases (C1–C4). Therefore cracking had to be modulated to produce the correct molecular size adjustment without scission to too much smaller fragments. Skeletal isomerization was to be maximized. The activity in both acid-catalyzed reactions had to be tuned while keeping a stable activity level. The only pretreatment condition assessed was the calcination temperature (screened in the 600–800°C range). Calcination at 600°C produced the highest activity level while 700°C was convenient from the point of view of selectivity. The optimum temperature coincided with the production of the highest concentration of Brönsted acid sites. Regarding the reaction conditions, increasing temperature values augmented the conversion but also increased the cracking. Therefore optimum values were found at a moderate temperature, 225°C, given the high reactivity of the feed. Space velocity values were analyzed with attention to the liquid C5+ yield, the selectivity to branched isomers and the stability of the catalysts. Best yields to branched naphtha products were obtained at WHSV=18h–1. The H2/hydrocarbon molar ratio was a function of the catalyst coking rate. A value of 10 was enough to attain a stable conversion value. The values of liquid yield as a function of pressure displayed a volcano pattern that was rationalized in terms of a non-classical bifunctional mechanism of reaction. High pressure values increased the concentration of Brönsted acid sites and hence the activity while high pressures enhanced hydrocracking and decreased the liquid yield. The optimal pressure value was 20atm. [Copyright &y& Elsevier]

Abstract: In this study, sulphated zirconia was directly synthesised and compared to the conventional wet method of preparation. The surface areas and pore sizes were 169m2/g, 0.61μm (directly synthesized) and 65m2/g, 0.24μm (conventional method), respectively. Directly synthesized sulphated zirconia was amorphous, whereas conventionally prepared sulphated zirconia is polycrystalline. Their IR spectra were broadly similar, although the area of the 1250 to 950cm−1 band was larger for directly synthesised sulphated zirconia. Not only were conversions greater for directly synthesised sulphated zirconia (63% vs. 42% after 4h), but it exhibited significantly greater yield for fatty acid methyl esters. The percentage yield (after 1h) of methyl esters was 43% for the directly synthesised catalyst and 15% for the conventionally synthesised. [Copyright &y& Elsevier]

Fluidized-bed catalytic cracking of heavy petroleum distillates is one of the most important processes in petroleum refining; because of its large scale, estimation of the kinetic rate constants is performed at the laboratory level. Several experimental devices are commonly used, including fixed-bed reactors, fluidized-bed reactors, and riser emulator reactors. Despite the different hydrodynamics of the reactors mentioned, when compared to the industrial unit, the production of the main products (gasoline, gases, and coke) can be predicted and emulated accurately in the laboratory. Taking advantage of this fact, prediction of the kinetic rate constants and catalyst activity parameters has been performed at the laboratory level; however, frequency factors are larger than those necessary to simulate the industrial unit. This situation could arise because of the lack of fundamental modeling of transport phenomena and catalyst activity decay due to coke deposition; these phenomena have been modeled using side functions associated with “time-on-stream”, “coke-on-catalyst”, or “feedstock conversion”. The objective of this work is to improve accuracy during estimation of the frequency factors at the laboratory level, via the estimation of catalyst activity, based on the effectiveness factor; which has been included in the mathematical model of a fixed-bed laboratory bench-scale reactor. It is shown that following activity evolution along the experiment time helps to calculate frequency factors that are very similar to those needed to simulate industrial units; moreover, this model estimates different catalyst activity for each reactant and each reaction, and, therefore, it is selective. Frequency factors for a lumped kinetic scheme obtained at the laboratory level are used to simulate an industrial unit, showing good agreement during prediction of the product yields. [ABSTRACT FROM AUTHOR]

Mixed oxides (Al−Si, Zr−Si, Mg−Si) were synthesized by the sol−gel method at different gelation times. The synthesized supports were impregnated by the incipient wetness method to obtain Ni−Mo, Co−Mo, and Ni−W supported catalysts. Both the supports and catalysts were characterized by N2physisorption for determining textural properties, and their catalytic activities were tested with isopropyl alcohol (2-propanol) and cumene decomposition in order to evaluate their acid−base properties. According to the obtained products, it was possible to assess qualitatively that Al−Si and Zr−Si supports and their respective catalysts were mainly acidic. In the case of NiMo/AlSi catalyst, high conversion during cumene cracking particularly at higher temperatures was observed. Cracking activity results indicated that surface acidity predominated due to Brønsted acid sites, which are mainly dependent on the support composition as well as their preparation methods. Conversion of isopropyl alcohol leads to the dehydration products, typically propylene with a very low amount of di-isopropyl ether or acetone. NiMo/AlSi catalyst was evaluated for cumene cracking and its kinetic parameters were obtained by applying the Langmuir−Hinshelwood model. The activation energy was found to be 27.75 kcal mol−1while the heat of adsorption calculated with the Van’t Hoff equation was −14.15 kcal mol−1taking into account a single-site surface reaction. [ABSTRACT FROM AUTHOR]

Ni/ZSM-5 catalyst is prepared using an incipient wet impregnation method with 4 wt% of Ni on mildly framework dealuminated ZSM-5 and studied for its physicochemical properties and light alkane conversions. X-ray diffraction (XRD) and pore size distribution studies envisioned the formation of Ni crystallites smaller than 0.55 nm in the zeolite pore channels of Ni/ZSM-5. The Ni/ZSM-5 exhibited better cracking and produced more liquefied petroleum gas (LPG) in the presence of N2 (LPG mode) and better aromatization activity in the presence of H2 (aromatic mode). This has resulted in the production of gasoline blending stock with a Research Octane Number (RON) of 91. [ABSTRACT FROM AUTHOR]

Fast pyrolysis of poplar wood followed with catalytic cracking of the pyrolysis vapors was performed using analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The catalysts applied in this study were nano MgO, CaO, TiO2, Fe2O3, NiO and ZnO. These catalysts displayed different catalytic capabilities towards the pyrolytic products. The catalysis by CaO significantly reduced the levels of phenols and anhydrosugars, and eliminated the acids, while it increased the formation of cyclopentanones, hydrocarbons and several light compounds. ZnO was a mild catalyst, as it only slightly altered the pyrolytic products. The other four catalysts all decreased the linear aldehydes dramatically, while the increased the ketones and cyclopentanones. They also reduced the anhydrosugars, except for NiO. Moreover, the catalysis by Fe2O3 resulted in the formation of various hydrocarbons. However, none of these catalysts except CaO were able to greatly reduce the acids. [ABSTRACT FROM AUTHOR]

The article presents a study that aims to examine the possibility of rectorite replacing kaolin for preparing fluid catalytic cracking (FCC) catalysts using in-situ synthesis technique. Rectorite is a natural aluminosilicate mineral that has physicochemical properties comparable to kaolin like its chemical composition, thermal behavior, and chemical reactivity. It was concluded that a suitably treated rectorite mineral can substitute kaolin for synthesizing FCC catalysts.

A new process of catalyst particles separations based on hydrocyclone technology is designed and an industrial sidetrack tester was set up in an 1.8 Mt/a catalytic cracking unit. In order to improve the separation efficiency of catalyst particles from oil slurry by hydrocyclones, the computational fluid dynamics method was used to optimize the geometry design of the hydrocyclone. Based on the simulation, a new design is proposed and proves to be able to improve the performance of hydrocyclone considerably. The catalyst solid particles concentrations in the range of 7,080-12,210 mg/L can be reduced to the range of 1,520-5,660 mg/L by the hydrocyclone. The method of hydrocyclone separation is feasible to remove catalyst particles from oil slurry. [ABSTRACT FROM AUTHOR]

The influence of reaction conditions on aromatization, deactivation, and regeneration properties of Nano-HZSM-5 zeolite catalyst were introduced when it was applied to catalytic cracking gasoline aromatization. The experimental results showed that the optimal conditions are reaction temperature of 430°, reaction pressure 0.3 MPa, and liquid hour space velocity 1.0 h-1. The aromatization properties of deactivated Nano-HZSM-5 catalyst maintained steadiness for one to two regenerations. [ABSTRACT FROM AUTHOR]

Abstract: In petroleum industry, it is desirable to produce lighter hydrocarbons such as gasoline, kerosene and gas–oil from unused heavy oils. Thus we have developed zirconia-supporting iron oxide catalysts to decompose petroleum residual oil (atmospheric distilled residual oil) with steam. In addition, we have found that the incorporation of among crystals is effective in improving the catalytic activity and stability of the ZrO2–FeO X catalyst. In this study, the effects of and content in –based catalysts on catalytic activity and stability were investigated. Furthermore, the –based catalyst was applied to the decomposition of extra heavy oils such as vacuum distilled residual oil and Orimulsion. These extra heavy oils were effectively decomposed over the ZrO2–Al2O3–FeO X catalyst with steam, and the yields of lighter hydrocarbon reached to above 60% [Copyright &y& Elsevier]

Abstract: The thermal cracking and the thermal catalytic cracking of soybean oil were evaluated for the production of biofuels as an alternative to fossil fuels. The catalyst proposed for the cracking reaction was bauxite, a high-acidity and low-cost catalyst. The chromatographic profile of the biofuels obtained by cracking showed hydrocarbon compounds such as alkanes, alkenes and aromatics, as well as some oxygenated compounds such as carboxylic acids, ketones and alcohols. The products generated by the thermal catalytic cracking process showed better results than the thermal cracking products because of the low quantity of acids present. The catalyst used was thus shown to act in the secondary cracking process, in which the fatty acids decompose and generate hydrocarbons. [Copyright &y& Elsevier]

Abstract: Instrumental neutron activation analysis (INAA) of fluid catalytic cracking (FCC) catalyst samples was carried out with an objective to identify activable elements and evaluate its suitability for use as an intrinsic radiotracer for tracing catalyst itself in Fluid Catalytic Cracking Units (FCCUs) used in petroleum refining. Two catalyst samples obtained from two different refineries were analyzed. Twelve different elements were identified in each catalyst sample and their respective concentrations were determined. From the recorded gamma-ray spectra, it was found that lanthanum-140 (140La) and sodium-24 (24Na) were the predominantly present and suitable radionuclides that could be used as radiotracers for tracing catalyst in FCCUs. Lanthanum being present in much higher concentration forms the major component of the radiotracer after irradiation. Based on the results of INAA, appropriate quantities of the catalyst samples were irradiated with neutrons to produce the desired amount of activity of lanthanum-140 and sodium-24 to be used as radiotracers for tracing the catalyst itself in a pilot as well as an industrial-scale FCCU. The residence time distribution (RTD) of catalyst was measured and analyzed to determine mean residence time (MRT). The axial dispersion model (ADM) was used to simulate the measured RTD data and investigate the degree of axial mixing. The results of the experiments were used to improve the design of pilot-scale FCCU and optimize the performance of the industrial-scale FCCU. [Copyright &y& Elsevier]

HMCM-22 zeolite with a high Si/Al2 ratio (158) was applied to the 1-butene cracking reaction in a fixed-bed reactor. On basis of the product distribution, the main reaction pathways of C4 alkenes catalytic transforming on HMCM-22 were proposed. Also, the preferences of the reaction pathways influenced by the temperature and conversion level were discussed, which could provide good guidance on enhancing the propene production. [ABSTRACT FROM AUTHOR]

A comprehensive study has been made on the cracking abilities of mesoporous aluminosillicate MCM-41 materials with different Si/Al ratios (15–∞) and pore diameters (1.6–3.0 nm) by using 1,3,5-triisopropylbenzene (1,3,5-TiPB) cracking as the test reaction. The roles of Al content and pore diameter on the catalytic features of the samples were evaluated by the conversion of 1,3,5-TiPB, coke content and deactivation parameters. It is found that the catalytic activity is mainly controlled by adsorptive properties towards the reactant and the dispersion of acid sites. In terms of their catalytic performances, cracking reaction over aluminosilicate mesoporous materials is more favorable for catalysts with smaller pore size and higher Al concentration. Moreover, coking is found responsible for catalyst deactivation during 1,3,5-TiPB cracking reaction over Al-MCM-41. [ABSTRACT FROM AUTHOR]

A two-dimensional reactor model incorporating hydrodynamics, mass balance, energy balance, and a 4-lump/14-lump kinetic model was established to simulate the riser and downer based fluid catalytic cracking (FCC) processes. The kinetic parameters of the 4-lump kinetic model were re-evaluated from the originally published experimental data for a more reliable description of the FCC process. The 14-lump kinetic model based on a molecular description of cracking and hydrogen transfer reactions was to include more details about the feedstock composition, reaction mechanisms, and the products distribution for a better understanding on the reactor performance for FCC process. This comprehensive model captured the key characteristics of the gas−solid reacting flows in the riser and downer, i.e., the uniformity of flow structures, the distinct backmixing behavior in the riser and downer, and the momentum and energy balances during the complex FCC reactions. The model predictions were first validated against industrial data from several literature sources and found to agree with each other reasonably well. Then, the simulations were carried out to fully understand the different reactor performances of riser and downer in the application of FCC refining processes. It can be concluded that the downer benefits from its advantages of the plug-flow nature and uniform flow structures, tending to have more products in the middle distillates, e.g., gasoline and light olefins, especially under high-severity operations. Better control of the reaction extent for increased selectivity to desired intermediate products would allow the use of downer reactors for the larger-scale practical applications in the FCC process, together with the valuable byproduction of light olefins. [ABSTRACT FROM AUTHOR]

Abstract: Clay-based materials show a natural forgiveness towards the incorporation of a variety of materials, including potentially hazardous industrial rejects or sub-products. Research from the past few years suggests that the red clay ceramics industry might become the natural end-user of waste materials from other industries. In Brazil, the growth of the petroleum industry is leading to an increasing amount of wastes with high environmental impact and the industry is looking for alternatives to the simple disposal of the wastes. The study reported here shows the changes in properties of an industrial red clay-based mixture, already in use in the production of bricks, due to additions of a spent catalyst reject material (SCR) discarded by the thermal cracking process in the petroleum industry. Samples containing 20 wt.% SCR were extruded and sintered in air in an electric furnace (700–1150 °C, for 1 h). The results obtained (X-ray diffraction and fluorescence, thermal analysis, firing shrinkage, water absorption and mechanical strength) show the effect of the SCR additions and suggest that the incorporation of the SCR material into the clay mixture can constitute a valid route to the amelioration of the environmental concerns. [Copyright &y& Elsevier]

Mathematical models and simulations of an integrated downer−regenerator FCC unit are presented. The models describe the steady-state nonisothermal behavior of the interdependent heavy oil cracking downflow reactor and catalyst regeneration fluidized-bed reactor. The models are rooted in four-lump cracking reaction kinetics and complete combustion kinetics for the regenerator reactions. Simulations results for the downer-type unit are partially validated against data collected in a 0.1−0.3 b/day pilot plant that was operated in the high-severitymode. The results are fairly reasonable especially in regard to predicting the performance of the cracking reactor. [ABSTRACT FROM AUTHOR]

This paper presents the experimental results regarding the effect of coke deposition on the cracking catalyst acidity. It was investigate two to FCC catalysts, PREMIX and VISION fresh and coked by the vacuum distillate cracking reaction. It was established the total acidity and strength of acidity by adsorption and thermodesorption of NH3. The increasing of coke contents on the catalyst involves to decreasing of total acidity and redistribution of acidity strength from the medium to wake strength. The number of high strength acidity site remains practically constant. [ABSTRACT FROM AUTHOR]

A simple procedure is developed to determine the apparent rate constants, reaction orders, and activation energies of various hydrotreating reactions, such as the hydrodesulfurization (HDS), hydrodemetalation (HDM), hydrodenitrogenation (HDN), and asphaltene cracking (HDAsph) of hydrotreating catalysts loaded in multiple-reactor fixed bed units. The procedure is derived from the basic kinetic and engineering principles. The only required input parameters are the sulfur, vanadium, nickel, nitrogen, and asphaltenes contents in the feedstock and products, reaction temperatures, and liquid hourly space velocity (LHSV). These parameters are normally available from laboratories performing the kinetic studies. Since there is no correlation coefficient in the developed kinetic expression, the apparent reaction rate constant and activation energy for various hydrotreating reactions can be determined directly once the optimum value of the reaction order has been identified. To demonstrate how the procedure works, it has been applied to calculate the kinetic values published in the open literature. Excellent agreements are obtained. The procedure is further verified with kinetic parameters from experiments undertaken in our pilot plants. In some cases, kinetic values which were unable to be determined in our pervious studies can now be obtained. The overall absolute average deviation (AAD) is less than 10%. [ABSTRACT FROM AUTHOR]

Industrial trials detailed in a riser−downer coupling reactor proposed for the fluid catalytic cracking (FCC) process are presented in this paper. The trials are based on the fundamental research of hydrodynamics, mixing behaviors, and laboratory-scale hot experiments described in our previous investigations. Compared with the riser reactor with the same feeds and catalyst, the LPG and propylene yield increased by 8.15 and 4.30 wt %, respectively. The gasoline octane number likewise reached 94.8 with 28 wt % olefin content. However, dry gas is significantly suppressed, and the coke has little change in yield even with the increased catalyst to oil ratio. With some gasoline recycling, the LPG and propylene yield increased by 11.45 and 5.06 wt %, respectively, and the olefin content in gasoline significantly decreased to 22 wt %; the high octane number (95.4) is maintained. The computational fluid dynamics (CFD) coupled with a 6-lump kinetic model is also applied to simulate the FCC process for the industrial trials. The yield of propylene and butylene and the temperature profile along the axis direction demonstrated consistency between the simulation results and the experimental data. [ABSTRACT FROM AUTHOR]

Abstract: The catalytic transformation of methylcyclohexane (mcha), as representative of the reactions taking place during catalytic cracking, was carried out on a H-EU-1 zeolite under the following conditions: 623 K, atmospheric pressure, ratio equal to 9, contact time (taken as the reciprocal of the weight hourly space velocity) between 0.016 and 0.3 h. Whatever the contact time and time-on-stream, cracking was the main reaction, like on other 10-MR zeolites, but significant amounts of isomers and aromatics were produced. Moreover, cracking led predominantly to branched products, in contradiction with the shape selectivity expected from the narrow pore openings of this 10-MR zeolite. All this could be explained by a very important catalytic contribution of the protonic sites located at the pore mouths. Additional experiments using bulky basic compounds (γ-collidine) confirmed this hypothesis and allowed estimation of the selectivity of these acid sites. [Copyright &y& Elsevier]

The modified RFG-FSIR catalyst was used in one catalytic cracking unit for reducing olefin content (v) of catalytically cracked gasoline. RFG-FSIR was the model number of the catalytic agent. The experimental data were compared with the blend data. As a result, activity, stability, and fluidization capability of this catalyst were good. More than that, this catalyst can reduce olefin content effectively. At the same time, octane number of catalytically cracked gasoline was reduced. All in all, this catalyst was effective. [ABSTRACT FROM AUTHOR]

Catalytic cracking of high-density polyethylene (HDPE) over fluid catalytic cracking (FCC) catalysts (1:6 ratio) was carried out using a laboratory fluidized bed reactor operating at 450°C. Two fresh and two steam deactivated commercial FCC catalysts with different levels of rare earth oxide (REO) were compared as well as two used FCC catalysts (E-Cats) with different levels of metal poisoning. Also, inert microspheres (MS3) were used as a fluidizing agent to compare with thermal cracking process at BP pilot plant at Grangemouth, Scotland, which used sand as its fluidizing agent. The results of HDPE degradation in terms of yield of volatile hydrocarbon product are fresh FCC catalysts≫steamed FCC catalysts≈used FCC catalysts. The thermal cracking process using MS3 showed that at 450°C, the product distribution gave 46wt% wax, 14% hydrocarbon gases, 8% gasoline, 0.1% coke and 32% nonvolatile product. In general, the product yields from HDPE cracking showed that the level of metal contamination (nickel and vanadium) did not affect the product stream generated from polymer cracking. This study gives promising results as an alternative technique for the cracking and recycling of polymer waste. [Copyright &y& Elsevier]

This work presents the relation between the pozzolanic activity, the hydration heat and the compressive strength developed by blended mortars containing 10 and 35% of a spent fluid catalytic cracking catalyst (FCC). The results show that, in comparison with 100% Portland cement mortar, a mortar with 10% FCC increases the hydration heat all over the period of testing. This hydration heat increasing is due to the pozzolanic effect, therefore the resulting compressive strength is higher than the reference mortar. Whereas, in a mortar with 35% of FCC, the hydration heat is higher than 100% PC mortar, until 10 h of testing. After this age, the substitution degree predominates over the pozzolanic activity, showing in this case, lower hydration heat and developing lower compressive strength than 100% PC mortar. [ABSTRACT FROM AUTHOR]

Abstract: Cu/Mg/Al ternary HT-derived materials show significantly better SO x trap performances with respect to binary Cu/Al HT-derived materials and represent an interesting type of material either to protect NO x traps from the deactivation by sulphur or as SO x additives in fluid catalytic cracking (FCC) applications. The kinetics of SO2 uptake was studied at low (10ppm) and higher (1000ppm) SO2 concentration in a thermobalance (TG) apparatus. The results were compared with those obtained by measuring the SO2 breakthrough curves in a flow reactor under reaction conditions simulating those of autoexhaust gases, in particular regarding the use of high space-velocities and the presence of CO2 in the feed. The SO x trap performances depend on the feed composition and type of experiments. However, a similar ranking of the SO x trap performances was observed for the different configurations. Cu/Mg/Al=1:1:2 shows the best performance and also improved hydrothermal stability with respect to Cu/Al binary samples. [Copyright &y& Elsevier]

Abstract: The non-stationary cracking of methane over various noble metal/CeO2-doped catalysts at 400 and 600°C was followed by DRIFT spectroscopy and on the basis of the identified elementary steps a simplified kinetic modeling is proposed. The production of H2 by direct decomposition of CH4 on the noble metal is improved by the capacity of ceria to store carbonaceous surface species thanks to: (i) the spillover of carbonyls from noble metal particles towards basic hydroxyls formed on partially reduced Ce sites and (ii) the reverse spillover of ceria oxygen towards metal to oxidize the carbon issued from methane cracking. The resulting formate adspecies are in turn oxidized into carbon dioxide during the regeneration step. Doping the ceria with basic lanthanide oxides and replacing Pt by more efficient and eventually better dispersed metals for methane decomposition like Rh and Ir lead to significant improvements in the hydrogen productivity. [Copyright &y& Elsevier]

Abstract: The effective simulation of the fluid catalytic cracking (FCC) operation requires a good understanding of many factors such as, reaction kinetics, fluid dynamics, and feed and catalyst effects. The different product slates that can be obtained are the consequence of a complex reaction scheme including cracking, isomerization, hydrogen transfer, oligomerization, etc. Furthermore, the catalyst deactivation may affect each one of the reactions in different ways, which creates an additional reason for different variation with time-on-stream of the yield to each product. On the basis of the experimental data of the FCC pilot plant operated in Chemical Process Engineering Research Institute (CPERI, Thessaloniki, Greece), a lumping model was developed for the prediction of the FCC product distribution. The lumped reaction network involved five general lumps (gas oil, gasoline, coke, liquefied product gas, and dry gas) to simulate the cracking reactions and to predict the gas oil conversion and the product distribution. The paths of catalyst deactivation were studied and a selective deactivation model was adopted that enhances the fundamentality and accuracy of the lumping scheme. The hypothesis of selective catalyst deactivation was found to improve the product slates prediction. Models with different assumptions were examined, regarding the behavior of the catalyst, as deactivated, and its effect on the reactions of the lumping scheme. A large database of experiments, performed in the FCC pilot plant of CPERI was used to verify the performance of the models in steady state unit operation. The simulation results depict the importance of incorporating selective catalyst deactivation functions in FCC lumping models. [Copyright &y& Elsevier]

Most heterogeneous catalyst supports used in refineries are composed of porous alumina ceramics. Drying has been identified as a critical process for final product mechanical strength. In the literature, numerous papers deal with drying-induced stresses, which can lead to crack initiation. However, there are few papers devoted to experimental study of drying conditions that promote cracking. The objective of this work is to enhance knowledge of cracking behavior, specifically by studying alumina gel drying. First, the relation between drying conditions and first crack initiation is studied experimentally. Then a complete thermo-hydro-mechanical characterization of the alumina gel is made, including moisture content as a parameter. [ABSTRACT FROM AUTHOR]

Oxidative cracking of bitumen, waxy fuel oil, and used transformer oils were carried out individually in an autoclave with 0.6 wt% of hydroquinone as a catalyst. The cracking process is conducted at 410°C in an atmosphere of oxygen gas of 0.15 MPa, for 30 min. The identification and quantitative determination of both the liquids and gases obtained during the cracking process are achieved using packed and capillary gas chromatography (GC) connected with suitable detectors. It was found that the degraded liquid products obtained have a higher percentage of lower hydrocarbons compared to the original feed stocks. Several analytical parameters including API gravity, calorific value, viscosity, density, pour point, etc., were used to evaluate the liquid product obtained. Also, the calorific values of the liberated gases were calculated and compared with that of natural gas. The cracked oil products were distilled and compared to their corresponding petroleum fractions. The cracked fractions have the same characteristics as their corresponding petroleum fractions with the exception of some properties that depend on the aromatic, naphthenic, and waxy nature of the virgin oil. [ABSTRACT FROM AUTHOR]

The axial and radial distribution of the catalyst concentration, in the riser of an EMC - experimental cold model of a fluid catalytic cracking type unit, was measured by gamma-absorption. The solid concentration in the circulating fluidized bed was determined by measurements with a 241Am gamma-source and a NaI(Tl) detector. The operation, instrumental measurements and data acquisition system of the cold unit were automated. The catalyst concentration measurements were carried out in static experiments and in the circulating fluidized bed. A calibration of the distribution concentration was made with experimental data from gas velocity and pressure drop along the riser that gave the best multi-regression model. A spatial resolution of 5.0 . 10-3 m by scanning the riser and a catalyst density resolution of 5.0±0.8 kg/m3 were obtained. The axial catalyst concentration distribution, in the 5-13 kg/m 3 interval, showed a predicted pattern according to the literature. The radial distribution was in an annular configuration for this diluted catalyst concentration. [ABSTRACT FROM AUTHOR]

Abstract: The utilization of exhausted fluid catalytic cracking (FCC) catalysts as raw materials for the zeolite synthesis was analyzed. Samples of the catalysts directly released from FCC units and the corresponding impact grinding pretreated samples were used. Mechanical treatment was observed to decrease catalyst crystallinity and particle size. The catalyst reactivity was analyzed in terms of conversion in zeolite and product properties. Hydrothermal synthesis experiments in NaOH medium were performed. Catalysts conversion in A and X type zeolites was obtained for treated and not treated samples. In particular, high conversion in NaX type were achieved using the more siliceous catalyst, whereas grinding activation produces a decrease of particle size and Al/Si ratio of the zeolites obtained. [Copyright &y& Elsevier]