Hydrodemetallization chemistry

The optimum catalyst and the optimum processing conditions for hydrodemetallation will depend upon the feedstock and the process application. To the extent that metal deposits determine the operating lifetime of the catalyst, knowledge of the intrinsic metal removal chemistry and molecular transport processes will enable prediction of metal deposition location within catalysts and will provide criteria for optimum catalyst design. 

S-compounds, N-compounds and M (Metal) compounds have different reactivities and chemistry depending on the boiling ranges of fractions in which they are found. Thus, specific processes have been developed for the removal of each of these impurities. These are classified as hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodemetallation (HDM) processes, respectively. These are in turn subdivided into processes, which are optimized for the boiling range of the particular feedstock being treated. 

---