Hydrogenation through Partial Oxidation of Hydrocarbons in Supercritical Water

Abstract

Catalytic hydrogenation of naphthalene and dibenzothiophene through a water gas shift reaction (CO+H₂→CO₂+H₂) in supercritical water (SCW) is studied. Experiments were conducted with NiMo/Al₂O₃ at 673 K and 30-32 MPa, in various atmospheres (H₂-SCW, CO-SCW, CO₂-H₂-SCW etc.), by using a tube bomb reactor. The results show that higher conversion of naphthalene was obtained in CO-SCW and in CO₂-H₂-SCW than in H₂-SCW. These results cleary indicate that the water-gas shift reaction in SCW produces species which have higher hydrogenationg reactivity than H₂ gas in SCW. Partial oxidation of hexylbenzene and n-hexadecane in SCW were also studied. At low water density (0-0.16g/cm³), CO₂ Was the main product. However, with increasing water density (up to 0.52g/cm³), the CO₂ ratio tended to decrease while the CO and H₂ ratios increased.