Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2022 Jul 22:10:807225.
doi: 10.3389/fchem.2022.807225. eCollection 2022.

Perspectives on strategies for improving ultra-deep desulfurization of liquid fuels through hydrotreatment: Catalyst improvement and feedstock pre-treatment

Tendai O Dembaremba  1 , Siphumelele Majodina  1 , Ryan S Walmsley  2 , Adeniyi S Ogunlaja  1 , Zenixole R Tshentu  1
Affiliations
Review

Perspectives on strategies for improving ultra-deep desulfurization of liquid fuels through hydrotreatment: Catalyst improvement and feedstock pre-treatment

Tendai O Dembaremba et al. Front Chem. .

Abstract

Reliance on crude oil remains high while the transition to green and renewable sources of fuel is still slow. Developing and strengthening strategies for reducing sulfur emissions from crude oil is therefore imperative and makes it possible to sustainably meet stringent regulatory sulfur level legislations in end-user liquid fuels (mostly less than 10 ppm). The burden of achieving these ultra-low sulfur levels has been passed to fuel refiners who are battling to achieve ultra-deep desulfurization through conventional hydroprocessing technologies. Removal of refractory sulfur-containing compounds has been cited as the main challenge due to several limitations with the current hydroprocessing catalysts. The inhibitory effects of nitrogen-containing compounds (especially the basic ones) is one of the major concerns. Several advances have been made to develop better strategies for achieving ultra-deep desulfurization and these include: improving hydroprocessing infrastructure, improving hydroprocessing catalysts, having additional steps for removing refractory sulfur-containing compounds and improving the quality of feedstocks. Herein, we provide perspectives that emphasize the importance of further developing hydroprocessing catalysts and pre-treating feedstocks to remove nitrogen-containing compounds prior to hydroprocessing as promising strategies for sustainably achieving ultra-deep hydroprocessing.

Keywords: adsorptive denitrogenation; crude oil; denitrogenation; desulfurization; fuel refinery; hydroprocessing; hydroprocessing catalysts; metal-organic frameworks.

PubMed Disclaimer

Conflict of interest statement

Ryan Walmsley is employed by Sasol Technology (Pty) Ltd. All authors declare no other competing interests. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
Maximum sulfur limits in (A) gasoline 2021 and (B) on-road diesel 2021, and gap between current vehicle emission standards and (C) gasoline quality and (D) on-road diesel quality (Global Fuel Specification, 2022).
FIGURE 2
FIGURE 2
Hydroprocessing examples based on the process conditions (temperature and pressure) (Bose, 2015).
FIGURE 3
FIGURE 3
Schematic of the sulfidation process for CoMo catalyst showing DBT binding on a coordinatively unsaturated Mo site (Moqadam and Mahmoudi, 2013).
FIGURE 4
FIGURE 4
A representation of an alumina supported catalyst showing the movement of electrons on the active sites.
FIGURE 5
FIGURE 5
Schematic representation of the multiple interaction sites in the highly selective MOF, (Cr)-MIL-101-SO3Ag, reported by She et al. (She et al., 2018).
See this image and copyright information in PMC

References

    1. Abdul-Quadir M. S., Ferg E. E., Tshentu Z. R., Ogunlaja A. S. (2018). Remarkable adsorptive removal of nitrogen-containing compounds from hydrotreated fuel by molecularly imprinted poly-2-(1H -imidazol-2-yl)-4-phenol nanofibers. RSC Adv. 8 (15), 8039–8050. 10.1039/c8ra00543e - DOI - PMC - PubMed
    1. Abdul-Quadir M. S., van Der Westhuizen R., Welthagen W., Ferg E. E., Tshentu Z. R., Ogunlaja A. S., et al. (2018). Adsorptive denitrogenation of fuel over molecularly imprinted poly-2-(1H-imidazol-2-yl)-4-phenol microspheres. New J. Chem. 42 (15), 13135–13146. 10.1039/c8nj02818d - DOI
    1. Abdul-quadir M. S., van der Westhuizen R., Welthagen W., Ferg E. E., Tshentu Z. R., Ogunlaja A. S., et al. (2019). Selective removal of organonitrogen compounds in fuel using functional polybenzimidazole nanofibres: A combined experimental and theoretical study. S. Afr. J. Chem. 72, 88–100. 10.17159/0379-4350/2019/v72a12 - DOI
    1. Abro R., Abro M., Gao S., Bhutto A. W., Ali Z. M., Shah A., et al. (2016). Extractive denitrogenation of fuel oils using ionic liquids: A review. RSC Adv. 6, 93932–93946. 10.1039/c6ra09370a - DOI
    1. Ahmed I., Jhung S. H. (2014). Adsorptive denitrogenation of model fuel with CuCl-loaded metal–organic frameworks (MOFs). Chem. Eng. J. 251, 35–42. 10.1016/j.cej.2014.04.044 - DOI

LinkOut - more resources