Modeling of vaporization and cracking of liquid oil injected in a gas–solid riser

Nayak, Subramanya; Joshi, Saket L.; Ranade, Vivek V.

doi:10.1016/j.ces.2005.04.046

Cited by 93 publications

(119 citation statements)

References 28 publications

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“…The first lumping scheme was proposed by Weekman and Nace in 1970 [20], namely the 3-lump kinetic scheme, which grouped the kinetics of an FCC reactor in gasoil, gasoline, light gases and coke species. Later on, in 1988, Yen et al [21] split the third lump to separate light gases and coke lumps respectively, and formulated the most commonly used [1, 3,6,17,22] 4-lump scheme.…”

Section: Cracking Path and Liquid-gas Properties For Petroleum Fractimentioning

confidence: 99%

“…In the majority of CFD works related to the FCC reactors [1, [3][4][5][6][7][8][9][10], the hydrodynamic equations are coupled with lump reaction kinetics in order to present a holistic/general view of the reactor/catalytic cracking yields. The "lump" species, as they are called, are groups of different species that exhibit similar behaviour and are used in order to overcome the difficulty that lies in the characterization of the exact components that constitute petroleum fraction liquids and the exact catalytic cracking reactions products.…”

Section: Cracking Path and Liquid-gas Properties For Petroleum Fractimentioning

confidence: 99%

“…The conditions that should be taken into account throughout the droplet path are: a) injection conditions such as feed preheat (478-673 K [13,18]), injected drop velocity (45 to 100m/s [13]) and drop sizes (50-500μm [6,8,17]), b) reactor conditions, like bed pressure (1.5-3 bar (Table 10.2 of [19])) and temperature (769-838K [13]), as well as c) catalyst conditions, such as size (60-75 μm [6,7,17]), mean velocity (6-17m/s [13,17]) and temperature (950-1005K [13]). The mean operating conditions for droplet-particle collisions inside the FCC injection zone were gathered from selective representative studies [1, 3-10, 13, 17-19] and are presented in Figure 1b.…”

Section: Operating Conditions In the Fcc Injection Zonementioning

confidence: 99%

“…In these studies, a 2-phase flow approach is used in order to simulate the mixing/reactions of solid catalysts with gas flowing inside FCC reactors. In [6,7] however, the importance of studying the FCC injection zone, and more specifically the liquid feed vaporization is highlighted, as it is an important aspect for the correct calculation of the cracking yields and products selectivity. For this reason, in recent CFD works [6][7][8][9][10][11] the additional investigation of the injected droplets motion, coupled with a vaporization model has been performed.…”

Section: Introductionmentioning

confidence: 99%

“…In [6,7] however, the importance of studying the FCC injection zone, and more specifically the liquid feed vaporization is highlighted, as it is an important aspect for the correct calculation of the cracking yields and products selectivity. For this reason, in recent CFD works [6][7][8][9][10][11] the additional investigation of the injected droplets motion, coupled with a vaporization model has been performed. This has allowed the full 3-phase (solid catalysts/liquid droplets/gas) problem exhibited in real FCC reactors to be resolved, where however the detail achieved in the injection zone is not enough to capture the real interactions occurring between cold injected droplets and hot catalytic particles.…”

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of heavy fuel droplet-particle collisions in the injection zone of a Fluid Catalytic Cracking reactor, Part I: Numerical model and 2D simulations

Malgarinos

Νikolopoulos

Gavaises

2017

Fuel Processing Technology

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent repository link AbstractThe present paper investigates the collisions between heavy gasoil droplets and solid catalytic particles taking place at conditions realized in Fluid Catalytic Cracking reactors (FCC). The computational model utilizes the Navier-Stokes equations along with the energy conservation and transport of species equations. The VOF methodology is used in order to track the liquid-gas interface, while a dynamic local grid refinement technique is adopted, so that high accuracy is achieved with a relative low computational cost. Phase-change phenomena (evaporation of the heavy gasoil droplet), as well as catalytic cracking surface reactions are taken into account. Physical properties of heavy and light molecular weight hydrocarbons are modeled by representative single component species, while a 2-lump scheme is proposed for the catalytic cracking reactions. The numerical model is firstly validated for the case of a single liquid droplet evaporation inside a hot gaseous medium and impingement onto a flat wall for droplet heating and film boiling conditions. Afterwards, it is utilized for the prediction of single droplet-catalyst collisions inside the FCC injection zone. The numerical results indicate that droplets of similar size to the catalytic particles tend to be levitated more easily by hot catalysts, thus resulting in higher cracking reaction rates/cracking product yield, and limited possibility for liquid pore blocking. For larger sized droplets, the corresponding results indicate that the production of cracking products is not favored, while solid-liquid contact increases. Hotter catalysts promote catalytic cracking reactions and droplet levitation over the catalytic particle, owed to the formation of a thin vapour layer between the liquid and the solid particle.

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