To describe the structure of contaminant materials that cause deactivation and to find relations between structures of components in the feed oil and in the contaminants, in order to understand the deactivation of catalysts used for hydrotreating and hydroconversion of heavy fractions.
The structure and the functions of the alumina supported Co/Mo and Ni/Mo catalysts seem to be well understood and the deactivation is thought to be mainly the result of contamination. All feeds cause deposition of coke, and some feeds, especially residual fractions, contain metals which deposit as sulphides on the catalyst. The amounts of coke and metal sulphides can be exorbitant - in some cases the catalyst weight has been observed to more than double during use - and part of the deactivation undoubtedly is due to physical constrictions giving rise to pore diffusion limitations.
The research project is divided into three tasks:
1) "Ageing experiments/structural analyses". This represents the experimental stage, where catalyst deactivation is demonstrated in a variety of ways, and the structure and structural changes in coke and other contaminants are being studied.
Samples containing metals as contaminant will be taken from stock because of the very extended experimental programme that would be needed to regenerate new samples.
2) "Understanding deactivation". The structural analyses are extended into an attempt at explaining the influence that the catalyst carrier, the active materials and the various contaminants have upon one another, and a basic understanding of the deactivation phenomena is attempted.
3) "Modelling deactivation". Depending on the success of the experiments and the depth of understanding of the deactivation, it should now be possible to conclude the project with "rate equations" for the deactivation and a mathematical model that will allow prediction of catalyst performance as a function of time and process parameters over a range that incorporates even high severity, high conversion processes.
Even though the results may turn out more modestly, we can with confidence expect to obtain a valuable tool for catalyst performance prediction, and perhaps most importantly, guidelines for modification of catalysts and processes with the result that deactivation is reduced and the lifetime is prolonged.