The main cause of this may be the high oxygen heteroatom content of the feedstock originating from the triglyceride part (10% triglyceride in the feedstock means about 1.1% of oxygen content). During the triglyceride hydrogenation, after splitting the propane the oxygen removal is faster from the linear fatty acid chains (higher reaction rate) than the desulphurisation of cyclic/polycyclic sulphur compounds