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.

A Historic Review on R&D of China’s FCC Riser Termination Device Technologies

2013 ◽  
Vol 11 (1) ◽  
pp. 225-242 ◽  
Author(s):  
Chunxi Lu ◽  
Yongmin Zhang ◽  
Mingxian Shi
Keyword(s):  
Catalytic Cracking ◽  
Geometry Optimization ◽  
Operating Conditions ◽  
Fluid Catalytic Cracking ◽  
Processing Capacity ◽  
Centrifugal Separation ◽  
Recovery Efficiency ◽  
The World ◽  
Historic Review ◽  
Fcc Technology

Abstract Fluid catalytic cracking (FCC) is a dominant refining conversion process in China’s most refineries. After decades of development, China has already become one of the major FCC technology licensors in the world. In this review, the research and development (R&D) activities on FCC riser termination device (RTD) technologies in China are reviewed and discussed. Emphasis is put on the R&D of a series of advanced RTD technologies led by China University of Petroleum, Beijing, which initiated in the early 1990s when more and more China’s FCC units chose to process more residue feedstock. Followed by the guideline of three “quick”s and two “high”s, two early types of RTD systems with coupled zones for gas–solids centrifugal separation and pre-stripping were developed and applied successfully in commercial units. Significantly reduced yields of coke and dry gas due to restrained post-riser reactions and satisfactory particle recovery efficiency were achieved. These were the fender-stripper cyclone and vortex quick separator systems designed for external- and internal-riser FCC units, respectively. Later, further improvement efforts led to the development of another two RTD systems, i.e. the circulating-stripper cyclone system for external-riser units and super vortex quick separator system for internal-riser units. By now, nearly 50 applications were commissioned with a sum FCC capacity of 40.0 Mton/a, nearly one-third of China’s total FCC processing capacity. Besides, other research efforts, such as the geometry optimization efforts on LD2 type separator, the studies on RTD for down-flow riser FCC units, and the idea of non-disengager FCC unit are also discussed in this review. To accommodate to degraded feedstock, more stringent environmental regulations and new FCC process technologies, future R&D efforts on RTD technologies should be put on improvements to further satisfy the three-“quick”s and two-“high”s requirements with changing FCC operating conditions and different process requirements.

Location and Surface Species of Fluid Catalytic Cracking Catalyst Contaminants: Implications for Alleviating Catalyst Deactivation

2016 ◽  
Vol 30 (12) ◽  
pp. 10371-10382 ◽  
Author(s):  
U. J. Etim ◽  
Pingping Wu ◽  
Peng Bai ◽  
Wei Xing ◽  
Rooh Ullah ◽  
...  
Keyword(s):  
Catalytic Cracking ◽  
Catalyst Deactivation ◽  
Fluid Catalytic Cracking ◽  
Surface Species

Solids-Loading Measurements in a Gas-Solid Riser

Volume 1 ◽  
2004 ◽  
Author(s):  
T. J. O’Hern ◽  
S. M. Trujillo ◽  
J. B. Oelfke ◽  
P. R. Tortora ◽  
S. L. Ceccio
Keyword(s):  
Catalytic Cracking ◽  
Volume Fraction ◽  
Electrode System ◽  
Operating Conditions ◽  
Fluid Catalytic Cracking ◽  
Gas Velocity ◽  
Cross Sectional ◽  
Solids Loading ◽  
Special Cases ◽  
Superficial Gas Velocity

Gas-solid multiphase flows are commonly used in chemical processing, petroleum fluid catalytic cracking, and other industrial applications. The distribution of the solid phase in gas-solid flows (generally in the form of small particles) is seldom uniform, but more commonly involves clusters, streamers, and core-annular distributions, depending on the flow orientation and the overall gas and solid flowrates and their ratio. For this reason, tomographic techniques are of great interest for measurement of cross-sectional solids distributions in such flows. The cross-sectional profiles of solids loading can be integrated to yield a cross-sectionally averaged solids loading. Determination of this averaged solids loading is needed to understand the axial variations of solids loading and its sensitivity to flow parameters and to optimize performance. A common technique for determining volume-averaged solids loading in vertical flows like the riser section of a circulating fluidized bed (CFB) is by measurement of the time-averaged axial pressure gradients along the riser axis (differential pressure or ΔP method). Neglecting acceleration and wall friction, the axial momentum balance simplifies to equate the multiphase hydrostatic pressure term with the pressure gradient along the axis. Many authors (e.g., Louge and Chang, 1990) have pointed out the neglected terms in this approach and generally show that ΔP is applicable in the special cases of no solids-loading gradient (fully developed flow) or small solids flux. A more generally applicable technique for measuring solids loading in gas-solid flows is gamma tomography. A gamma tomography system using a 100-mCi Cs-137 source collimated into a fan beam and an array of scintillation detectors, has been developed and implemented for application to a cold-flow (non-reacting) CFB. The CFB has a 14-cm-ID 6-m tall riser, and is currently operated with a multiphase mixture of air and fluid catalytic cracking (FCC) catalyst particles. Typical operating conditions include mean superficial gas velocities up to 7.4 m/s and solids fluxes up to approximately 100 kg/m2·s. Quantitative comparison of gamma- and ΔP-determined solids loadings was made over a range of operating conditions (combination of superficial gas velocity and solids flux). Results indicate that the differences between gamma and ΔP-determined cross-sectionally averaged solids loading are most pronounced near the base of the riser, where solids concentration is highest and the mixture is accelerating. Higher in the riser, the agreement is better. Additionally, the difference is larger in cases of higher superficial gas velocity. In addition, several studies were performed to design an electrical-impedance tomography (EIT) system for a gas-solid flow to collect data suitable for validating computational models. A two-electrode bulk impedance system was studied experimentally. The required accuracy, spatial resolution and temporal resolution of an EIT system are addressed, and modeling and reconstruction are discussed. Bulk solid volume fractions measured by the two-electrode system and by gamma-densitometry tomography are in general agreement. Experiments with the two-electrode system also show that the Maxwell-Hewitt relation, used to convert the mixture impedance to solid volume fraction, must be applied carefully, paying attention to the identity of the dispersed and continuous phases. The design of a 16-electrode system is also described.

Availability modeling and estimation of Fluid Catalytic Cracking Unit using generalized Stochastic Petri Nets

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Thangamani Gurunathan
Keyword(s):  
Complex System ◽  
Petri Nets ◽  
Catalytic Cracking ◽  
Operating Conditions ◽  
Fluid Catalytic Cracking ◽  
Stochastic Petri Nets ◽  
Common Cause ◽  
Content Type ◽  
Common Cause Failures ◽  
Generalized Stochastic Petri Nets

PurposeThe purpose of this paper to present a practical and systematic approach to estimate the availability of a process plant using generalized stochastic Petri nets (GSPNs). The actual live problem at a fluid catalytic cracking unit (FCCU) of a refinery is used to demonstrate this approach.Design/methodology/approachA majority of models used for estimation of availability of a complex system are based on the assumptions that the failure of the system is associated with only a few states, and the system does not face different operating conditions, repair actions and common-cause failures. In reality, this is often not the case. Therefore, it is necessary to construct more sophisticated models without such assumptions. In this paper, an attempt has been made to model interaction of component failures, partial failures of components and common-cause failures.FindingsThe superiority of this approach over other modeling approaches such as fault tree and Markov analysis is demonstrated. The proposed GSPN is a promising tool that can be conveniently used to model and analyze any complex systems.Practical implicationsGSPN was used to model the reactor-regenerator section of FCCU, which is quite a large system, which shows the strength of modeling capability. The use of Petri nets (PNs) for modeling complex systems for the purpose of availability assessment is demonstrated in this paper. Sensitivity analysis was also carried out for various subsystem/components.Originality/valueNo similar work has been conducted for FCCU using GSPN as per literature incorporating different operating conditions and common-cause failures. The understanding and usage of PNs require a steep learning curve for the practitioners, and this paper provides an approach to estimate availability measures for the complex system.

Fuel production by cracking of polyolefins pyrolysis waxes under fluid catalytic cracking (FCC) operating conditions

2019 ◽  
Vol 93 ◽  
pp. 162-172 ◽  
Author(s):  
Elena Rodríguez ◽  
Alazne Gutiérrez ◽  
Roberto Palos ◽  
Francisco J. Vela ◽  
José M. Arandes ◽  
...  
Keyword(s):  
Catalytic Cracking ◽  
Operating Conditions ◽  
Fluid Catalytic Cracking ◽  
Fuel Production

scholarly journals Performance Assessment of Sintered Metal Fiber Filters in Fluid Catalytic Cracking Unit

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Liang Yang ◽  
Zhongli Ji ◽  
Qiaoqi Xu ◽  
Hao Li
Keyword(s):  
Catalytic Cracking ◽  
Particle Concentration ◽  
High Efficiency ◽  
Operating Conditions ◽  
Fluid Catalytic Cracking ◽  
Maximum Pressure ◽  
Stable Operation ◽  
Metal Fiber ◽  
Sintered Metal ◽  
Median Diameter

A long-term test was performed in a fluid catalytic cracking (FCC) hot gas filtration facility using sintered metal candle filters. The operating temperature and pressure were maximum 55°C and 0.28 MPa, respectively. Specific particle sampling systems were used to measure the particle size and concentration directly at high temperature. The range of inlet particle concentration is from 150 to 165 mg/Nm3. The outlet particle concentration is in the range of 0.71–2.77 mg/Nm3in stable operation. The filtration efficiency is from 98.23% to 99.55%. The inlet volume median diameter and the outlet volume median diameter of the particle are about 1 μm and 2.2 μm, respectively. The cake thickness is calculated based on the equation of Carman-Kozeny. The effects of operating parameters including face velocity, gas cleaning pressure, pulse duration, and maximum pressure drop were investigated. The optimal operating conditions and cleaning strategies were determined. The results show that sintered metal fiber filters are suitable for industrial application due to the good performance and high efficiency observed.

scholarly journals A Review of Modelling of the FCC Unit. Part I: The Riser

Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 308
Author(s):  
Thabang W. Selalame ◽  
Raj Patel ◽  
Iqbal M. Mujtaba ◽  
Yakubu M. John
Keyword(s):  
Catalytic Cracking ◽  
Catalyst Deactivation ◽  
Ghg Emissions ◽  
Fluid Catalytic Cracking ◽  
Heavy Petroleum ◽  
Changing Trends ◽  
Cracking Reaction ◽  
Regenerator System ◽  
Kinetics Of ◽  
Modelling Approaches

Heavy petroleum industries, including the fluid catalytic cracking (FCC) unit, are useful for producing fuels but they are among some of the biggest contributors to global greenhouse gas (GHG) emissions. The recent global push for mitigation efforts against climate change has resulted in increased legislation that affects the operations and future of these industries. In terms of the FCC unit, on the riser side, more legislation is pushing towards them switching from petroleum-driven energy sources to more renewable sources such as solar and wind, which threatens the profitability of the unit. On the regenerator side, there is more legislation aimed at reducing emissions of GHGs from such units. As a result, it is more important than ever to develop models that are accurate and reliable, that will help optimise the unit for maximisation of profits under new regulations and changing trends, and that predict emissions of various GHGs to keep up with new reporting guidelines. This article, split over two parts, reviews traditional modelling methodologies used in modelling and simulation of the FCC unit. In Part I, hydrodynamics and kinetics of the riser are discussed in terms of experimental data and modelling approaches. A brief review of the FCC feed is undertaken in terms of characterisations and cracking reaction chemistry, and how these factors have affected modelling approaches. A brief overview of how vaporisation and catalyst deactivation are addressed in the FCC modelling literature is also undertaken. Modelling of constitutive parts that are important to the FCC riser unit such as gas-solid cyclones, disengaging and stripping vessels, is also considered. This review then identifies areas where current models for the riser can be improved for the future. In Part II, a similar review is presented for the FCC regenerator system.

Vitrification of Simulated Intermediate-Level French and Russian Wastes in “Cold Crucible” Based Plant

1995 ◽  
Vol 412 ◽  
Author(s):  
F. A. Lifanov ◽  
S. V. Stefanovsky ◽  
A. P. Kobelev ◽  
V. I. Kornev ◽  
A. E. Savkin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Chloride Ions ◽  
Experimental Plant ◽  
Cold Crucible ◽  
Process Variables ◽  
Comparative Tests ◽  
Operation Conditions ◽  
Operation Process ◽  
Infra Red ◽  
Sodium And Potassium

AbstractComparative tests on SGN and Radon simulated ILW vitrification with a cold crucible based experimental plant were performed. The batch was fed as paste with 20 wt.% moisture. An operation conditions, the ability of the cold crucible to maintain the differential pressure during the operation, process variables, product properties, off-gas and condensate compositions, the effect of melt agitation on melter capacity and cesium loss have been determined. Melt viscosity and resistivity have been measured. Material structures were studied using infra-red spectroscopy and electron microscopy. Leach rates of sodium and potassium cations as well as Cs-137 have been measured. The behavior of sulfate and chloride ions in the vitrification process as well as their solubility in SGN and “Radon” glasses have been investigated.

scholarly journals CFD Study of Industrial FCC Risers: The Effect of Outlet Configurations on Hydrodynamics and Reactions

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
Gabriela C. Lopes ◽  
Leonardo M. Rosa ◽  
Milton Mori ◽  
José R. Nunhez ◽  
Waldir P. Martignoni
Keyword(s):  
Catalytic Cracking ◽  
Flow Model ◽  
Numerical Study ◽  
Three Dimensional ◽  
Kinetic Scheme ◽  
Operating Conditions ◽  
Fluid Catalytic Cracking ◽  
Geometric Configurations ◽  
Three Phase ◽  
Three Phase Flow

Fluid catalytic cracking (FCC) riser reactors have complex hydrodynamics, which depend not only on operating conditions, feedstock quality, and catalyst particles characteristics, but also on the geometric configurations of the reactor. This paper presents a numerical study of the influence of different riser outlet designs on the dynamic of the flow and reactor efficiency. A three-dimensional, three-phase flow model and a four-lump kinetic scheme were used to predict the performance of the reactor. The phenomenon of vaporization of the liquid oil droplets was also analyzed. Results showed that small changes in the outlet configuration had a significant effect on the flow patterns and consequently, on the reaction yields.

Modelling Catalyst Deactivation by External Coke Deposition during Fluid Catalytic Cracking

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Gladys Jiménez-García ◽  
Roberto Quintana-Solórzano ◽  
Ricardo Aguilar-López ◽  
Rafael Maya-Yescas
Keyword(s):  
Catalytic Cracking ◽  
Catalyst Deactivation ◽  
Catalyst Activity ◽  
Effective Diffusivity ◽  
Fluid Catalytic Cracking ◽  
Coke Deposition ◽  
Negative Exponential Function ◽  
Operating Variables ◽  
Laboratory Reactor ◽  
Negative Exponential

Although the Fluid Catalytic Cracking (FCC) is an economic important process, simulation of its kinetics is rather empirical—mainly it is a consequence of the complex interactions among operating variables and the complex kinetics that take place. A crucial issue is the inevitable catalyst reversible deactivation, consequence of both, coke (by-product) deposition on the catalyst surface (external) and inside the catalytic zeolite (internal). In order to tackle this problem, two main proposals to evaluate deactivation rate by coking have been extensively applied, both use a probability distribution function called "the negative exponential function"—one of them uses the time that catalyst has been in the reacting stream (named Time-on-Stream), and the other is related to the coke amount on/inside the catalyst (denoted as Coke-on-Catalyst). These two deactivation models can be unified by tracking catalyst activity as function of the decrease on effective diffusivity due to pore occlusion (external) by coke—this situation leads to an increase of Thiele modules and consequently a decrease of the effectiveness factor of each reaction. This tracking of catalyst activity incorporates, implicitly, rates of reaction and transport phenomena taking place in the catalyst pores and is therefore phenomenological rather than statistical. In this work, the activity profiles predicted previously are reproduced at MAT laboratory reactor. The same approach is used to model an industrial riser and the results are in agreement with previous reports.

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