The Development of a Multi-Technique Approaches Towards the Study and Characterisation of Asphaltene Structures and Sub-Structures
Supervisor: John Hanna & Co-Supervisor: Prof Peter Dowding (Infineum UK Ltd.)
This PhD project is part of a larger, long-standing collaboration between the University of Warwick and Infineum UK Ltd in Milton Hill. Heavy Fuel Oil (HFO) is the high viscosity, tar-like substance, which is used to power ships in international waters. It remains after the distillation and subsequent cracking of crude oil to produce lighter fraction. HFO contains asphaltenes, resins, maltenes and many other low and high molecular weight organic fractions that can exhibit direct and indirect involvement in significant environmental problems. Asphaltenes are the complex fraction of crude oil which is soluble in aromatic solvents (e.g. toluene, etc.) but not in aliphatic solvents (e.g. pentane, etc.), which are mixtures of complex condensed aromatic hydrocarbons with sidechains up to C30. They also contain hetero-aromatic groups and bi- or polyfunctional molecules with nitrogen-based functionalities (i.e. amines, amides, etc.) and/or oxygen-based functionalities (e.g. ketones, amides, phenols, carboxylic acids, etc). In addition, their long-range structure can accommodate transition metal species such as Ni2+, Co2+ and V4+ which are complexed with the pyrrole N atoms to form metalated porphyrin ring structures. Numerous techniques have been developed to separate asphaltene fractions by functionality and properties (i.e. by their acid-base characteristics and their interfacially active components) which can determine/govern their ability leave macroscopic deposits in engine and exhaust environments. The aim of this PhD project will be to develop a combined methodology involving solid state NMR techniques, EPR measurements, vibrational spectroscopy and mass spectrometry in order to establish an overall protocol for the characterisation of these complex systems. In particular, one of the main objectives is to be able to detect and effectively measure the interfacially active fragments of the asphaltene networks and to understand their structure-function characteristics, in comparison/contrast to the remaining asphaltene fragments. Where possible, the structures of fragments containing heteroatoms and the influence of transition metal coordination will be determined. These outcomes will be rationalised against established environmental and engineering scenarios known to have a significant asphaltene involvement.
For further details please contact Professor John Hanna:
Start date: 27 September 2021