scholarly journals A Model of Catalytic Cracking: Catalyst Deactivation Induced by Feedstock and Process Variables

Catalysts ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 98
Author(s):  
Galina Y. Nazarova ◽  
Elena N. Ivashkina ◽  
Emiliya D. Ivanchina ◽  
Maria Y. Mezhova
Keyword(s):  
Catalytic Cracking ◽  
Catalyst Deactivation ◽  
Coke Formation ◽  
Experimental Studies ◽  
Main Process ◽  
Process Variables ◽  
Coke Content ◽  
Petroleum Fractions ◽  
Spent Catalysts

Changes in the quality of the feedstocks generated by involving various petroleum fractions in catalytic cracking significantly affect catalyst deactivation, which stems from coke formed on the catalyst surface. By conducting experimental studies on feedstocks and catalysts, as well as using industrial data, we studied how the content of saturates, aromatics and resins (SAR) in feedstock and the main process variables, including temperature, consumptions of the feedstock, catalyst and slops, influence the formation of catalytic coke. We also determined catalyst deactivation patterns using TG-DTA, N2 adsorption and TPD, which were further used as a basis for a kinetic model of catalytic cracking. This model helps predict the changes in reactions rates caused by coke formation and, also, evaluates quantitatively how group characteristics of the feedstock, the catalyst-to-oil ratio and slop flow influence the coke content on the catalyst and the degree of catalyst deactivation. We defined that a total loss of acidity changes from 8.6 to 30.4 wt% for spent catalysts, and this depends on SAR content in feedstock and process variables. The results show that despite enriching the feedstock by saturates, the highest coke yields (4.6–5.2 wt%) may be produced due to the high content of resins (2.1–3.5 wt%).

An analytical microscopic study of metals in fluidized catalytic cracking catalyst

1986 ◽  
Vol 44 ◽  
pp. 854-855
Author(s):  
Clifford S. Rainey
Keyword(s):  
Electron Microscopy ◽  
Spatial Distribution ◽  
Catalytic Cracking ◽  
Catalyst Deactivation ◽  
Coke Formation ◽  
Acid Sites ◽  
Y Zeolite ◽  
Fcc Catalyst ◽  
Fluidized Catalytic Cracking ◽  
High Regeneration

The spatial distribution of V and Ni deposited within fluidized catalytic cracking (FCC) catalyst is studied because these metals contribute to catalyst deactivation. Y zeolite in FCC microspheres are high SiO2 aluminosilicates with molecular-sized channels that contain a mixture of lanthanoids. They must withstand high regeneration temperatures and retain acid sites needed for cracking of hydrocarbons, a process essential for efficient gasoline production. Zeolite in combination with V to form vanadates, or less diffusion in the channels due to coke formation, may deactivate catalyst. Other factors such as metal "skins", microsphere sintering, and attrition may also be involved. SEM of FCC fracture surfaces, AEM of Y zeolite, and electron microscopy of this work are developed to better understand and minimize catalyst deactivation.

scholarly journals Bio-oil transformation into 2nd generation biofuels

Paliva ◽  
2020 ◽  
pp. 98-106
Author(s):  
Tomáš Macek ◽  
Miloš Auersvald ◽  
Petr Straka
Keyword(s):  
Catalytic Cracking ◽  
Catalyst Deactivation ◽  
Commercial Application ◽  
Petroleum Feedstock ◽  
2Nd Generation ◽  
Marine Transport ◽  
Petroleum Fractions ◽  
Bio Oil ◽  
The Usa ◽  
Refining Processes

The article summarized the possible transformations of pyrolysis bio-oil from lignocellulose into 2nd generation biofuels. Although a lot has been published about this topic, so far, none of the published catalytic pro-cesses has found commercial application due to the rapid deactivation of the catalyst. Most researches deal with bio-oil hydrotreatment at severe conditions or its pro-cessing by catalytic cracking to prepare 2nd generation biofuels directly. However, this approach is not commercially applicable due to high consumptions of hydrogen and fast catalyst deactivation. Another way, crude bio-oil co-processing with petroleum fractions in hydrotreatment or FCC units seems to be more promising. The last approach, bio-oil mild hydrotreatment followed by final co-processing with petroleum feedstock using common refining processes (FCC and hydrotreatment) seems to be the most promising way to produce 2nd generation biofuels from pyrolysis bio-oil. Co-processing of bio-oil with petroleum fraction in FCC increases conversion to gasoline and, thus, it could be a preferable process in the USA. Otherwise, co-hydrotreatment of hydrotreated bio-oil with LCO leads not only to the reduction of hydrogen consumption but also to the conversion preferably to diesel. This process seems to be more suitable for Europe. Further research on bio-oils upgrading is still necessary before the commercialization of the bio-oil conversion into biofuels suitable for cars. However, the first commercial bio-refinery that will convert bio-oil into biofuel for marine transport is planned to be built in the Netherlands.

scholarly journals Analysis of Process Variables via CFD to Evaluate the Performance of a FCC Riser

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
H. C. Alvarez-Castro ◽  
E. M. Matos ◽  
M. Mori ◽  
W. Martignoni ◽  
R. Ocone
Keyword(s):  
Catalytic Cracking ◽  
Catalyst Deactivation ◽  
Fluid Dynamic ◽  
Industrial Process ◽  
Operating Conditions ◽  
Fluid Catalytic Cracking ◽  
Process Variables ◽  
Cracking Behavior ◽  
Operation Conditions ◽  
Operation Process

Feedstock conversion and yield products are studied through a 3D model simulating the main reactor of the fluid catalytic cracking (FCC) process. Computational fluid dynamic (CFD) is used with Eulerian-Eulerian approach to predict the fluid catalytic cracking behavior. The model considers 12 lumps with catalyst deactivation by coke and poisoning by alkaline nitrides and polycyclic aromatic adsorption to estimate the kinetic behavior which, starting from a given feedstock, produces several cracking products. Different feedstock compositions are considered. The model is compared with sampling data at industrial operation conditions. The simulation model is able to represent accurately the products behavior for the different operating conditions considered. All the conditions considered were solved using a solver ANSYS CFX 14.0. The different operation process variables and hydrodynamic effects of the industrial riser of a fluid catalytic cracking (FCC) are evaluated. Predictions from the model are shown and comparison with experimental conversion and yields products are presented; recommendations are drawn to establish the conditions to obtain higher product yields in the industrial process.

scholarly journals A Model of Catalytic Cracking: Product Distribution and Catalyst Deactivation Depending on Saturates, Aromatics and Resins Content in Feed

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 701
Author(s):  
Galina Y. Nazarova ◽  
Elena N. Ivashkina ◽  
Emiliya D. Ivanchina ◽  
Alexander V. Vosmerikov ◽  
Ludmila N. Vosmerikova ◽  
...  
Keyword(s):  
Catalytic Cracking ◽  
Catalyst Deactivation ◽  
Experimental Studies ◽  
Product Distribution ◽  
Vacuum Gasoil ◽  
Light Gasoil ◽  
Wet Gas ◽  
Mixed Feedstock

The problems of catalyst deactivation and optimization of the mixed feedstock become more relevant when the residues are involved as a catalytic cracking feedstock. Through numerical and experimental studies of catalytic cracking, we optimized the composition of the mixed feedstock in order to minimize the catalyst deactivation by coke. A pure vacuum gasoil increases the yields of the wet gas and the gasoline (56.1 and 24.9 wt%). An increase in the ratio of residues up to 50% reduces the gasoline yield due to the catalyst deactivation by 19.9%. However, this provides a rise in the RON of gasoline and the light gasoil yield by 1.9 units and 1.7 wt% Moreover, the ratio of residue may be less than 50%, since the conversion is limited by the regenerator coke burning ability.

scholarly journals Catalyst/Feedstock Ratio Effect on FCC Using Different Catalysts Samples

Catalysts ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 542
Author(s):  
Abdualkaber Alkhlel ◽  
Hugo de Lasa
Keyword(s):  
Catalytic Cracking ◽  
Catalyst Deactivation ◽  
Coke Formation ◽  
Chemical Reactor ◽  
Fluidized Catalytic Cracking ◽  
Ammonia Desorption ◽  
Temperature Programmed ◽  
Fcc Catalysts ◽  
Engineering Centre

The present study is a follow-up to a recent authors contribution which describes the effect of the C/O (catalyst/oil) ratio on catalytic cracking activity and catalyst deactivation. This study, while valuable, was limited to one fluidized catalytic cracking (FCC) catalyst. The aim of the present study is to consider the C/O effect using three FCC catalysts with different activities and acidities. Catalysts were characterized in terms of crystallinity, total acidity, specific surface Area (SSA), temperature programmed ammonia desorption (NH3-TPD), and pyridine chemisorption. 1,3,5-TIPB (1,3,5-tri-isopropyl benzene) catalytic cracking runs were carried out in a bench-scale mini-fluidized batch unit CREC (chemical reactor engineering centre) riser simulator. All data were taken at 550 °C with a contact time of 7 s. Every experiment involved 0.2 g of 1,3,5-TIPB with the amount of catalyst changing in the 0.12–1 g range. The resulting 0.6–5 g oil/g cat ratios showed a consistent 1,3,5-TIPB conversion increasing first, then stabilizing, and finally decreasing modestly. On the other hand, coke formation and undesirable benzene selectivity always rose. Thus, the reported results show that catalyst density affects both catalyst coking and deactivation, displaying an optimum C/O ratio, achieving maximum hydrocarbon conversions in FCC units.

The system of indicators of the quality of the carbon-carbon composite materials and technologies of their production

2018 ◽  
pp. 127-132
Author(s):  
T. N. Antipova ◽  
D. S. Shiroyan
Keyword(s):  
Composite Material ◽  
Low Cost ◽  
Experimental Studies ◽  
Carbon Matrix ◽  
Carbon Composite ◽  
Optimal Number ◽  
Laboratory Equipment ◽  
Carbon Composite Material ◽  
Carbon Composite Materials

The system of indicators of quality of carbon-carbon composite material and technological operations of its production is proved in the work. As a result of the experimental studies, with respect to the existing laboratory equipment, the optimal number of cycles of saturation of the reinforcing frame with a carbon matrix is determined. It was found that to obtain a carbon-carbon composite material with a low cost and the required quality indicators, it is necessary to introduce additional parameters of the pitch melt at the impregnation stage.

scholarly journals Research on Hazardous Waste Removal Management: Identification of the Hazardous Characteristics of Fluid Catalytic Cracking Spent Catalysts

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2289
Author(s):  
Haihui Fu ◽  
Yan Chen ◽  
Tingting Liu ◽  
Xuemei Zhu ◽  
Yufei Yang ◽  
...  
Keyword(s):  
Surface Water ◽  
Hazardous Waste ◽  
Environmental Quality ◽  
Catalytic Cracking ◽  
Petroleum Refining ◽  
Fluid Catalytic Cracking ◽  
Refining Industry ◽  
Spent Catalyst ◽  
Spent Catalysts ◽  
Petroleum Refining Industry

Fluid catalytic cracking (FCC) spent catalysts are the most common catalysts produced by the petroleum refining industry in China. The National Hazardous Waste List (2016 edition) lists FCC spent catalysts as hazardous waste, but this listing is very controversial in the petroleum refining industry. This study collects samples of waste catalysts from seven domestic catalytic cracking units without antimony-based passivation agents and identifies their hazardous characteristics. FCC spent catalysts do not have the characteristics of flammability, corrosiveness, reactivity, or infectivity. Based on our analysis of the components and production process of the FCC spent catalysts, we focused on the hazardous characteristic of toxicity. Our results show that the leaching toxicity of the heavy metal pollutants nickel, copper, lead, and zinc in the FCC spent catalyst samples did not exceed the hazardous waste identification standards. Assuming that the standards for antimony and vanadium leachate are 100 times higher than that of the surface water and groundwater environmental quality standards, the leaching concentration of antimony and vanadium in the FCC spent catalyst of the G set of installations exceeds the standard, which may affect the environmental quality of surface water or groundwater. The quantities of toxic substances in all spent FCC catalysts, except those from G2, does not exceed the standard. The acute toxicity of FCC spent catalysts in all installations does not exceed the standard. Therefore, we exclude “waste catalysts from catalytic cracking units without antimony-based passivating agent passivation nickel agent” from the “National Hazardous Waste List.”

scholarly journals Catalytic Hot Gas Cleanup of Biomass Gasification Producer Gas via Steam Reforming Using Nickel-Supported Clay Minerals

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1875
Author(s):  
Prashanth Reddy Buchireddy ◽  
Devin Peck ◽  
Mark Zappi ◽  
Ray Mark Bricka
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Steam Reforming ◽  
Catalyst Deactivation ◽  
Nickel Content ◽  
Coke Formation ◽  
Biomass Gasification ◽  
Supported Nickel Catalyst ◽  
Fuel Gas ◽  
Removal Efficiencies

Amongst the issues associated with the commercialization of biomass gasification, the presence of tars has been one of the most difficult aspects to address. Tars are an impurity generated from the gasifier and upon their condensation cause problems in downstream equipment including plugging, blockages, corrosion, and major catalyst deactivation. These problems lead to losses of efficiency as well as potential maintenance issues resulting from damaged processing units. Therefore, the removal of tars is necessary in order for the effective operation of a biomass gasification facility for the production of high-value fuel gas. The catalytic activity of montmorillonite and montmorillonite-supported nickel as tar removal catalysts will be investigated in this study. Ni-montmorillonite catalyst was prepared, characterized, and tested in a laboratory-scale reactor for its efficiency in reforming tars using naphthalene as a tar model compound. Efficacy of montmorillonite-supported nickel catalyst was tested as a function of nickel content, reaction temperature, steam-to-carbon ratio, and naphthalene loading. The results demonstrate that montmorillonite is catalytically active in removing naphthalene. Ni-montmorillonite had high activity towards naphthalene removal via steam reforming, with removal efficiencies greater than 99%. The activation energy was calculated for Ni-montmorillonite assuming first-order kinetics and was found to be 84.5 kJ/mole in accordance with the literature. Long-term activity tests were also conducted and showed that the catalyst was active with naphthalene removal efficiencies greater than 95% maintained over a 97-h test period. A little loss of activity was observed with a removal decrease from 97% to 95%. To investigate the decrease in catalytic activity, characterization of fresh and used catalyst samples was performed using thermogravimetric analysis, transmission electron microscopy, X-ray diffraction, and surface area analysis. The loss in activity was attributed to a decrease in catalyst surface area caused by nickel sintering and coke formation.

scholarly journals Molecular Responses during Plant Grafting and Its Regulation by Auxins, Cytokinins, and Gibberellins

Biomolecules ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 397 ◽  
Author(s):  
Anket Sharma ◽  
Bingsong Zheng
Keyword(s):  
Plant Hormones ◽  
Growth And Development ◽  
Molecular Mechanisms ◽  
Main Process ◽  
Graft Union ◽  
Physiological Processes ◽  
Current Review ◽  
Postharvest Life ◽  
Successful Production

Plant grafting is an important horticulture technique used to produce a new plant after joining rootstock and scion. This is one of the most used techniques by horticulturists to enhance the quality and production of various crops. Grafting helps in improving the health of plants, their yield, and the quality of plant products, along with the enhancement of their postharvest life. The main process responsible for successful production of grafted plants is the connection of vascular tissues. This step determines the success rate of grafts and hence needs to be studied in detail. There are many factors that regulate the connection of scion and stock, and plant hormones are of special interest for researchers in the recent times. These phytohormones act as signaling molecules and have the capability of translocation across the graft union. Plant hormones, mainly auxins, cytokinins, and gibberellins, play a major role in the regulation of various key physiological processes occurring at the grafting site. In the current review, we discuss the molecular mechanisms of graft development and the phytohormone-mediated regulation of the growth and development of graft union.

The Cooling Rate Effect on Graphene Synthesis Using Low Pressure Chemical Vapor Deposition

2021 ◽  
Author(s):  
Byoungdo Lee ◽  
Weishen Chu ◽  
Wei Li
Keyword(s):  
Chemical Vapor Deposition ◽  
Reaction Time ◽  
Carbon Source ◽  
Cooling Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Feeding Time ◽  
Process Variables ◽  
Pressure Chemical

Abstract Low-pressure chemical vapor deposition (LPCVD) is the most efficient method to synthesize large-scale, high-quality graphene for many potential applications such as flexible electronics, solar cells, and separation membranes. The quality of LPCVD is affected by process variables including methane/hydrogen (CH4/H2) ratio, time, pressure, temperature, and cooling rate. The cooling rate has been recognized as one of the most important process variables affecting the amount of carbon source, nucleation, reaction time, and thus the quality of the LPCVD. In this research, we investigate the effect of cooling rate on the quality of graphene synthesize by changing the cooling rate and the gas feeding time. Graphene coverage is measured by Raman mapping. It is found that fast cooling rate leads to decreased carbon source reaction time, which in turn results in higher coverage by monolayer graphene. The temperature-dependent gas feeding time corresponding to different cooling rates can be used to properly supply the carbon source onto the copper surface, also leading to a higher graphene coverage.

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