The suspending role of H sub(2)O and CO on catalytic hydrotreatment of gas-oil; myth or reality?

During co-hydroprocessing of petroleum fractions with liquid biomass, carbon monoxide (CO), carbon dioxide (CO sub(2)) and water (H sub(2)O) constitute some of the main by-products which take place due to the oxygen content of biomass. This study focuses on determining the H sub(2)O and CO effect on HDT reactions, as there is a certain controversy associated with their role. H sub(2)O and CO are artificially added during gas-oil catalytic hydrotreatment to investigate their influence in the potential biomass (i.e. lipids, bio-oil, tallow oil) catalytic co-hydroprocessing with fossil-based fractions for the production of hybrid fuels. Based on the experimental results, it is clearly inferred that the H sub(2)O role is neutral on heteroatoms' removal. On the contrary, CO has a suspending role not due to the resulting hydrogen partial pressure reduction, but rather to the inhibition of the catalyst active sites.