témavezető: Kovács Tibor
helyszín (magyar oldal): Pannon Egyetem, Radiokémiai és Radioökológiai Intézet helyszín rövidítés: PE
A kutatási téma leírása:
With the increasing use of opportunity crudes refiners are facing with deteriorating crude quality. Besides more contamination (salt, water, solids), crude incompatibility and higher acidity (TAN) the continuously increasing sulphur content poses a considerable problem at high temperature locations in the refinery.
Crude oil total sulphur content itself does not carry any important information from corrosion point of view. For the assessment of corrosivity, it is more practical to study the total sulphur content of the various distillates (sidecuts). Moreover the most informative if the individual sulphur compound types are determined.
In general most of the sulphur compounds itself are not corrosive. H2S is known to be the most problematic sulphur compound which can be found in small quantity in the raw crude compared to the other types of sulphur compounds (like thiols, mercaptanes, elementary sulphur, alcyl-sulphides, disulphides, tiophenes). It is generated by the thermal decomposition of the various sulfur containing compounds at 200-450oC.
Nowadays due to the increasingly deteriorating raw materials more and more new inhibitor molecules (preferably phosphate type) are developed to prevent high temperature sulfide corrosion of metal surfaces in industrial environments. Although a lot of inhibitor molecules are used nowadays, their mechanism of action on corrosion protection is unknown in most cases
On the surface of solid-liquid heterogeneous systems different mass and charge transport processes can be investigated with the in-situ radiotracer methods. In the last decades two different types of these methods namely the foil and the thin gap are widely used and developed in the Institute of Radiochemistry and Radioecology. With the parallel use of these applications and common electrochemical and surface analytical methods the corrosion and adsorption/desorption processes on the solid-liquid interfaces can be investigated. Namely the combination of radiotracer technique and voltammetry provide useful information on the mechanism of potential dependent adsorption processes. With the common electrochemical methods (e.g.: potentiostatic polarisation) the electrode processes of the corroded metal can be investigated (anodic dissolution, diffusion controlled oxygen reduction, hydrogen evolution, etc.). The morphology of the developed surface layers on different metals can be examined with SEM (Scanning Electron Microscopy) or AFM (Atomic Force Microscopy) techniques.
Task of the candidate:
The task of the candidate is twofold. Firstly analytical method development of the sulphur type compounds should be investigated. Secondly in-situ investigation of inhibitor sorption processes on precious metal, steel and iron surfaces with radiotraced inhibitor molecules. The widely used corrosion inhibitors are phosphorus based organic molecules, thus with the use of either 14C or 32P as radiotracer isotopes the processes can be examined. The corrosion inhibition should also be investigated with common electrochemical methods, while the morphology of surfaces should be measured with modern surface analytical methods.
felvehető hallgatók száma: 1
Jelentkezési határidő: 2020-08-31
2024. IV. 17. ODT ülés Az ODT következő ülésére 2024. június 14-én, pénteken 10.00 órakor kerül sor a Semmelweis Egyetem Szenátusi termében (Bp. Üllői út 26. I. emelet).
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