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A CFD study on the start-up hydrodynamics of fluid catalytic cracking regenerator integrated with chemical looping combustion

Erdoğan, Ahmet; Güleç, Fatih

A CFD study on the start-up hydrodynamics of fluid catalytic cracking regenerator integrated with chemical looping combustion Thumbnail


Authors

Ahmet Erdoğan

DR FATIH GULEC FATIH.GULEC1@NOTTINGHAM.AC.UK
Assistant Professor in Chemical and Environmental Engineering



Abstract

The integration of chemical looping combustion with fluid catalytic cracking (CLC-FCC) is an innovative concept that serves as a cost-effective method for CO2 capture in refineries. This approach has the potential to reduce refinery CO2 emissions by 25–35%, offering a promising solution. As in the conventional FCC unit, it is common for CLC-FCC regenerators to be exposed to an on-off process while they are being maintained and cleaned. The novelty of this research lies in its specific focus on a less-explored phase (start-up) of CLC-FCC regenerators, the application of advanced CFD modeling, and the comprehensive analysis of operational parameters that influence the system’s performance. To validate the CFD simulations of the different drag models for solid-gas granular, bed density profiles under steady-state conditions, collected from industrial processes, were used. For the flow period based on the start-up process of the drag models, the fluidization gas inlet geometry of the regenerator, flow regime (laminar and turbulent), and superficial gas velocity were comprehensively investigated to reveal their effects on hydrodynamic characteristics. The results show that Gidaspow and Syamlal-O’Brien drag models of the solid-gas multiphase granular flow exhibited a better fit with industrial data. The Syamlal-O’Brien and Gidaspow models closely align with industrial data under steady-state conditions, displaying similar bed densities in the dense phase region (230–310 kg/m3 for Syamlal-O’Brien and 235–300 kg/m3 for Gidaspow). During the initial stage (less than 0.2 seconds), both laminar and turbulent models yield comparable bed density profiles, approximately 510 kg/m3 in the dense phase. However, as the process progresses, the dense phase density decreases to about 250–350 kg/m3 at around 0.5 seconds, with laminar flow models showing a slightly better fit with industrial data. Notably, at 0.5 seconds of fluidization time, inlet geometries having better gas distribution achieve a highly diluted phase with bed densities of 10–20 kg/m3. Reaching a steady state, the bed density decreases from around 400 kg/m3 to 260–300 kg/m3, expanding into a higher section of the regenerator where it aligns well with industrial data. The increase in superficial gas velocity would result in the clarification of the difference and well mixing of the solid-gas multiphase flow.

Citation

Erdoğan, A., & Güleç, F. (in press). A CFD study on the start-up hydrodynamics of fluid catalytic cracking regenerator integrated with chemical looping combustion. Energy Sources, Part A, 46(1), 2941-2956. https://doi.org/10.1080/15567036.2024.2311327

Journal Article Type Article
Acceptance Date Jan 24, 2024
Online Publication Date Feb 7, 2024
Deposit Date Feb 1, 2024
Publicly Available Date Feb 12, 2024
Journal Energy Sources, Part A: Recovery, Utilization, and Environmental Effects
Print ISSN 1556-7036
Electronic ISSN 1556-7230
Publisher Taylor and Francis
Peer Reviewed Peer Reviewed
Volume 46
Issue 1
Pages 2941-2956
DOI https://doi.org/10.1080/15567036.2024.2311327
Keywords CO2 capture, Chemical Looping Combustion, Computational Fluid Dynamics, Hydrodynamics, CLC-FCC
Public URL https://nottingham-repository.worktribe.com/output/30660388
Additional Information Peer Review Statement: The publishing and review policy for this title is described in its Aims & Scope.; Aim & Scope: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=ueso20; Received: 2023-09-05; Accepted: 2024-01-24; Published: 2024-02-07

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Publisher Licence URL
https://creativecommons.org/licenses/by/4.0/

Copyright Statement
© 2024 The Author(s). Published with license by Taylor & Francis Group, LLC. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The terms on which this article has been published allow the posting of the Accepted Manuscript in a repository by the author(s) or with their consent.





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