The invention refers to a centrifugal separator for cleaning of a gas containing liquid impurities. The centrifugal separator comprises a stationary casing, which encloses a separation space and has an inner wall surface. A rotating member is provided in the separation space and arranged to rotate in a direction of rotation around an axis (x) of rotation. The rotating member brings the gas to rotation for separation of the liquid impurities from the gas. A gas outlet is provided for discharge of the cleaned gas. A first liquid outlet is provided downstream the rotating member for discharge of separated liquid impurities. The separation space comprises an annular surface which extends between the rotating member and the inner wall surface. The annular surface is configured to transport liquid impurities radially outwardly to the first liquid outlet.