  In this paper, for the first time we propose two linear, decoupled,
energy-stable numerical schemes for multi-component two-phase compressible flow
with a realistic equation of state (e.g. Peng-Robinson equation of state). The
methods are constructed based on the scalar auxiliary variable (SAV) approaches
for Helmholtz free energy and the intermediate velocities that are designed to
decouple the tight relationship between velocity and molar densities. The
intermediate velocities are also involved in the discrete momentum equation to
ensure the consistency with the mass balance equations. Moreover, we propose a
component-wise SAV approach for a multi-component fluid, which requires solving
a sequence of linear, separate mass balance equations. We prove that the
methods preserve the unconditional energy-dissipation feature. Numerical
results are presented to verify the effectiveness of the proposed methods.
