Enhanced olefin and aromatic production in a coupled bio-oil hydroprocessing and alkane dehydrogenation system
File(s)
Author(s)
Baubaid, Abdullah
Type
Thesis
Abstract
Biomass-derived oil (bio-oil) is regarded as a key hydrocarbon source capable of diminishing reliance on fossil fuels for chemicals. However, to prepare bio-oil for value-added chemical production, it must be upgraded by removing heteroatoms, mainly oxygen, through hydrodeoxygenation (HDO). Catalytic HDO of guaiacol, a bio-oil model compound, using in-situ produced hydrogen by alkane (ethane) dehydrogenation (DeH) is investigated to evaluate the use of an alternative to expensive molecular hydrogen (produced ex-situ). Coupling simultaneous ethane
DeH with bio-oil upgrading could be a potentially attractive process in terms of the economic outlook by co-producing ethylene, a high-value-added chemical, alongside aromatics and phenols. In this work, these tandem reactions are investigated using different configurations of hydroprocessing and/or alkane DeH catalytic systems and thermodynamic favourable operating conditions for HDO of guaiacol and ethane DeH to achieve valuable products. Alkane DeH demonstrated its potential as a hydrogen source by leading to an improvement in HDO product distribution with the production of species with no or lower oxygen content, benzene and phenol, besides the production of ethylene. However, the extent of HDO declines with time due to catalyst deactivation caused by oxygenated hydrocarbon condensate, which limits ethane from reaching active sites for hydrogen formation.
Yet, ethylene was co-produced in experiments that showed a better extent of HDO measured by O-to-aromatic ratio in comparison with the use of an excess of externally supplied hydrogen. The findings underscore the importance of ensuring stable hydrogen formation through DeH and maintaining selective HDO active sites within the catalyst bed to enhance the DeH-HDO coupling process’s efficacy. From an economic perspective, the coupling demonstrates significant potential in replacing hydrogen with on-purpose alkane DeH, as evidenced by experimental results. A set of reaction and process requirements are established, based on the experimental results and literature findings, to further enhance the coupling’s feasibility.
DeH with bio-oil upgrading could be a potentially attractive process in terms of the economic outlook by co-producing ethylene, a high-value-added chemical, alongside aromatics and phenols. In this work, these tandem reactions are investigated using different configurations of hydroprocessing and/or alkane DeH catalytic systems and thermodynamic favourable operating conditions for HDO of guaiacol and ethane DeH to achieve valuable products. Alkane DeH demonstrated its potential as a hydrogen source by leading to an improvement in HDO product distribution with the production of species with no or lower oxygen content, benzene and phenol, besides the production of ethylene. However, the extent of HDO declines with time due to catalyst deactivation caused by oxygenated hydrocarbon condensate, which limits ethane from reaching active sites for hydrogen formation.
Yet, ethylene was co-produced in experiments that showed a better extent of HDO measured by O-to-aromatic ratio in comparison with the use of an excess of externally supplied hydrogen. The findings underscore the importance of ensuring stable hydrogen formation through DeH and maintaining selective HDO active sites within the catalyst bed to enhance the DeH-HDO coupling process’s efficacy. From an economic perspective, the coupling demonstrates significant potential in replacing hydrogen with on-purpose alkane DeH, as evidenced by experimental results. A set of reaction and process requirements are established, based on the experimental results and literature findings, to further enhance the coupling’s feasibility.
Version
Open Access
Date Issued
2024-05-12
Date Awarded
2024-11-01
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Millan, Marcos
Publisher Department
Chemical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)