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

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.

Volume 1 ◽  
2004 ◽  
Author(s):  
T. J. O’Hern ◽  
S. M. Trujillo ◽  
J. B. Oelfke ◽  
P. R. Tortora ◽  
S. L. Ceccio

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.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Thangamani Gurunathan

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.


2019 ◽  
Vol 93 ◽  
pp. 162-172 ◽  
Author(s):  
Elena Rodríguez ◽  
Alazne Gutiérrez ◽  
Roberto Palos ◽  
Francisco J. Vela ◽  
José M. Arandes ◽  
...  

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Liang Yang ◽  
Zhongli Ji ◽  
Qiaoqi Xu ◽  
Hao Li

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.


2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
H. C. Alvarez-Castro ◽  
E. M. Matos ◽  
M. Mori ◽  
W. Martignoni ◽  
R. Ocone

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.


2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
Gabriela C. Lopes ◽  
Leonardo M. Rosa ◽  
Milton Mori ◽  
José R. Nunhez ◽  
Waldir P. Martignoni

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.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1089
Author(s):  
Zahra Gholami ◽  
Fatemeh Gholami ◽  
Zdeněk Tišler ◽  
Martin Tomas ◽  
Mohammadtaghi Vakili

The fluid catalytic cracking (FCC) process is an alternative olefin production technology, with lower CO2 emission and higher energy-saving. This process is used for olefin production by almost 60% of the global feedstocks. Different parameters including the operating conditions, feedstock properties, and type of catalyst can strongly affect the catalytic activity and product distribution. FCC catalysts contain zeolite as an active component, and a matrix, a binder, and a filler to provide the physical strength of the catalyst. Along with the catalyst properties, the FCC unit’s performance also depends on the operating conditions, including the feed composition, hydrocarbon partial pressure, temperature, residence time, and the catalyst-to-oil ratio (CTO). This paper provides a summary of the light olefins production via the FCC process and reviews the influences of the catalyst composition and operating conditions on the yield of light olefins.


Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 952
Author(s):  
Dicho Stoyanov Stratiev ◽  
Ivelina Kostova Shishkova ◽  
Rosen Kocev Dinkov ◽  
Ivan Petrov Petrov ◽  
Iliyan Venkov Kolev ◽  
...  

This paper evaluates the influence of crude oil (vacuum residue) properties, the processing of fluid catalytic cracking slurry oil, and recycle of hydrocracked vacuum residue diluted with fluid catalytic cracking heavy cycle oil, and the operating conditions of the H-Oil vacuum residue hydrocracking on the quality of the H-Oil liquid products. 36 cases of operation of a commercial H-Oil® ebullated bed hydrocracker were studied at different feed composition, and different operating conditions. Intercriteria analysis was employed to define the statistically meaningful relations between 135 parameters including operating conditions, feed and products characteristics. Correlations and regression equations which related the H-Oil® mixed feed quality and the operating conditions (reaction temperature, and reaction time (throughput)) to the liquid H-Oil® products quality were developed. The developed equations can be used to find the optimal performance of the whole refinery considering that the H-Oil liquid products are part of the feed for the units: fluid catalytic cracking, hydrotreating, road pavement bitumen, and blending.


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