Comparison of approaches to determine hydrogen consumption during catalytic hydrotreating of oil fractions

Different approaches to calculate the hydrogen consumption during hydrotreating of petroleum fractions are reviewed and discussed. Experimental information about the hydrotreating of various distillates (naphtha, light and heavy gasoils, atmospheric and vacuum residues) obtained in a bench-scale unit at typical operating conditions and commercial catalysts was used to determine the hydrogen consumption from global hydrogen balance and from the hydrogen balance in gas streams. The comparison of experimental hydrogen consumption calculated with the different approaches indicates that there is not a method that can predict hydrogen consumption with good accuracy. For quick calculation some correlations can be used, but the error can be as high as 15%. The common approach used in refineries, which does not take into account the dissolved hydrogen in the hydrotreated liquid, can give deviations up to 6% with respect to the experimental value. To account for this dissolved hydrogen into the balance all the correlations reported in the literature are suitable.