Influence of N- and O-containing heteroatoms on the continuous desulfurization of heavy oils and liquid fuels using catalytic oxidation of organic compounds with aqueous polyoxometalate solutions

• Applicants: Professor Dr.-Ing. Jakob Albert; Professor Dr.-Ing. Andreas Jess
• Subject Area: Chemical and Thermal Process Engineering ; Technical Chemistry
• Term: from 2014 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 265880028

Based on our successful preliminary investigations on the extractive-oxidative desulfurization of liquid fuels with in-situ product separation (ECODS), the overall goal of the follow-up project is to extend the previously developed technology to the separation of further heteroatoms from fuels and to fundamentally understand their effect on desulfurization. With regard to a technical implementation of the newly developed method, a spatial separation of the two reaction steps (substrate oxidation by oxygen, loading of the aqueous catalyst solution with oxygen) should also be carried out in a continuous process.In the previous, very successful project, an efficient system for oxidative-extractive desulfurization (aqueous HPA-5 solution) was found as an alternative to the hitherto industrial process of heterogeneously catalyzed hydrodesulfurization. The advantage of our system is that all desulfurization products (sulfuric acid, sulfonic acids, carboxylic acids) are extracted in-situ from the organic to the aqueous phase. This could be shown for model oils as well as for real oils.Essential for the continuation proposal is that our newly developed reaction system (aqueous HPA-5 solution) for the in-situ desulfurization of liquid fuels has the potential to efficiently desulfurize both aromatic and aliphatic systems. However, accumulation of decomposition products in the aqueous phase has been found to inhibit the catalyst system. This could be circumvented by the addition of oxalic acid. Based on these promising results, further investigations (as planned in the continuation proposal) are necessary with regard to the influence of N- and O-containing components in fuels on desulfurization. Thus, for example, N-containing fuel components such as indoles or quinolines could have a similar activating effect on our catalyst system, which could significantly contribute to the technical implementation of our concept. Therefore, in the continuation of the proposal, the influence of various N- and O-containing components on the oxidative-extractive desulfurization of liquid fuels should be fundamentally investigated. For this purpose, the influence on the basis of suitable model substances, e.g. the denitrification effect on the desulfurization of fuels should be investigated and understood. This approach has the potential to further enhance our newly developed desulfurization technology and, ideally, to combine it with the removal of further heteroatoms from liquid fuels.

• DFG Programme: Research Grants