Abstract
Through comparisons of dielectric constant (ε) and Hansen solubility parameter (HSP) of supercritical water (SCW) with those of typical solvents, conditions of SCW which has good miscibility with heavy oils were determined. The required conditions of SCW were found to be 2.2 ≤ ε ≤ 10.4 and HSP for hydrogen bonding, δh, < 10.0 MPa0.5. Validity of the optimum conditions estimated was confirmed by some experimental results.
