Impact of catalyst density distribution on the fluid dynamics of an ebullated bed operating at high gas holdup conditions

Parisien, Valois; Pjontek, Dominic; McKnight, Craig A.; Wiens, Jason; Macchi, Arturo

doi:10.1016/j.ces.2017.02.003

Cited by 8 publications

(3 citation statements)

References 49 publications

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“…For irregular catalyst shapes such as cylinders, experimental determination of n is preferable. In this model, n = 2.42, and is based on experiments using the spent (equilibrium) hydroprocessing catalyst from a commercial LC-FINING unit . The wall effect parameter k was assumed to be 1.0 because of the large column diameter of commercial units (∼3.6 m). …”

Section: Numerical Methodologymentioning

confidence: 99%

Modeling the Fluid Dynamics of a Commercial Ebullated Bed Hydroprocessor

Lane

Macchi

Pjontek

et al. 2019

Ind. Eng. Chem. Res.

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Ebullated bed hydroprocessors are a widely adopted technology for the upgrading of heavy oil. Because of the energy-intensive nature of this process, improvements and optimizations are highly desirable. As such, a complete understanding of the complex multiphase fluid dynamics in these units is still required to provide insight for future performance improvement. Specifically, current literature has not addressed the performance of the internal gas–liquid separation within the reactor and the impact of resulting entrained gas on overall reactor fluid dynamics. In this study, a novel numerical fluid dynamic model for a commercial scale ebullated bed hydroprocessor is proposed. A liquid residence time-based gas–liquid separation model is shown to be representative through analysis of commercial operating data. Freeboard gas holdups are predicted within 4% points for two generations of liquid recycle pans. Recycle pump speed is estimated within 10% points for the flow through pan.

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Section: Numerical Methodologymentioning

confidence: 99%

Modeling the Fluid Dynamics of a Commercial Ebullated Bed Hydroprocessor

Lane

Macchi

Pjontek

et al. 2019

Ind. Eng. Chem. Res.

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“…Heavy oil upgrading frequently makes use of ebullated bed reactors for thermally cracking and catalytically hydrogenating atmosphere and vacuum tower waste [3]. Significant attention has been paid to the implications of the internal recycling geometry on column performance, since these units have historically encountered very high solids-free gas hold-ups exceeding 30%, dislodging the heavy feed and restricting product throughput [4]. In an earlier attempt to lessen gas hold, a recycling pan was installed at the head of the ebullated bed reactor's internal recycle line [5].…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Gas Hold-Up of Two-Phase Ebullated Bed Reactor

Almukhtar,

Yahya,

Mahdy

et al. 2023

ChemEngineering

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Due to the significant increase in heavy feedstocks being transported to refineries and the hydrocracking process, the significance of adopting an ebullated bed reactor has been reemphasized in recent years. The predictive modelling of gas hold-up in an ebullated two-phase reactor was performed using 10 machine learning methods based on support vector machine (SVM) and Gaussian process regression (GPR) in this study. In an ebullated bed reactor, the impacts of three features, namely liquid velocity, gas velocity, and recycling ratio, on the gas hold-up were examined. The liquid velocity has the most impact on the predicted gas hold-up, according to the feature significance analysis. The rotational-quadratic, squared-exponential, Matern 5/2, and exponential kernel functions integrated with the GPR models and the linear, quadratic, cubic, fine, medium, and coarse kernel functions integrated with the SVM model performed well during training and testing, with the exception of the fine SVM model, whose R2 is very low. According to the R2 > 0.9 and low RMSE and MAE values, the rotational-quadratic, squared-exponential, and Matern 5/2 GPR models performed the best.

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“…Authors found that gas-liquid-solid fluidized bed dynamics of equivalent size spherical and cylindrical particles were similar in the dispersed bubble flow regime whereas differences were observed in the presence of larger coalescing bubbles. Parisien et al (2017) conducted experiments to investigate the impact of a wide particle density distribution on gas-liquid-solid fluidized beds phase holdups and bed behavior when operating under high gas holdup conditions relevant to the EBR. The experiments were performed at ambient temperature and pressure in a clear polyvinyl chloride column with a maximum expanded bed height of 2.7 m and an inner diameter of 0.152 m. The range of operating conditions was (u Lo = 0-47 mm/s, u G = 0-45 mm/s, P = 104 kPa).…”

Section: Introductionmentioning

confidence: 99%

Experimental and analysis study on dispersion of phases in an Ebullated Bed Reactor

Abid

Shanain

Abed³

2019

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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The effectiveness and performance of industrial hydro-processing Ebullated Bed Reactors (EBRs) are highly dependent on the bed hydrodynamics and operating conditions. In present work, hydrodynamics of EBRs was studied in a cold model experimental setup using air–water–solid particles system. Pressure gradient method and Residence Time Distribution (RTD) technique were used to estimate the individual holdups, and dispersion coefficients in the lab-scale ebullated bed column. System Hydraulic Efficiency (HEF) was also estimated. The results showed that liquid internal recycle ratio, which characterized the EBRs, has a predominant effect on the individual holdups and dispersion coefficients. Empirical correlations were developed for prediction of phase holdups, and dispersion coefficients with good accuracy.

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Impact of catalyst density distribution on the fluid dynamics of an ebullated bed operating at high gas holdup conditions

Cited by 8 publications

References 49 publications

Modeling the Fluid Dynamics of a Commercial Ebullated Bed Hydroprocessor

Modeling the Fluid Dynamics of a Commercial Ebullated Bed Hydroprocessor

Numerical Analysis of Gas Hold-Up of Two-Phase Ebullated Bed Reactor

Experimental and analysis study on dispersion of phases in an Ebullated Bed Reactor

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