Hydrogenation of bitumen in situ in supercritical water flow with and without addition of zinc and aluminum

Abstract

The conversion of bitumen (the gross-formula CH1.56N0.01S0.007) in supercritical water (SCW) flow at 400°C, 30MPa with and without addition of zinc and aluminum shavings into bitumen has been studied. For the conversion without addition of 〈Zn〉 and 〈Al〉 the yield of volatile and liquid products was 3.1 and 47.3%, respectively, in relation to the weight of bitumen. As a result of a chemical interaction of H2O molecules with bitumen, oxygen atoms appeared in these products and conversion residue; the amount of hydrogen in them being increased. When 〈Zn〉 or 〈Al〉 was added, the conversion and hydrogenation of bitumen significantly increased owing to hydrogen evolution during the oxidation of metals by SCW. This oxidation via the synthesis of ZnO and Al2O3 nanoparticles was accompanied by on-site heating of reactants. Moreover, when adding 〈Zn〉 and 〈Al〉 into bitumen, the yield of the volatile products increased up to 15.3 and 38.2%, respectively. The addition of 〈Zn〉 resulted in the yield increase of the liquid products up to 62.3%, of the resins up to 33.5%, the content of oxygen in the products being increased too. While the addition of 〈Al〉 resulted in the yield decrease of the resins up to 7.5% and the yield increase of the oil up to 36.1%, no oxygen atoms in the structure of the liquid products being detected. A portion of sulfur was removed from bitumen via the SCW conversion with addition of 〈Zn〉 in terms of the ZnO+H2S=ZnS+H2O reaction. These and other peculiarities of the conversion and hydrogenation of bitumen in situ are reported in the present paper.