Multiphase flow mixing apparatus and method of mixing

A subsea multiphase flow mixing apparatus for mixing a multiphase flow comprising at least a liquid phase and a gas phase, the apparatus comprising:

• at least one container which is configured to be disposed subsea and includes at least one inlet for the multiphase flow and at least one outlet located at a lower axial end of the container;
• a hollow flow regulating device which is axially arranged within the container and includes a lower first end located an axial distance from the outlet to thereby provide an axially extending drainage gap between the lower first end of the flow regulating device and a top of the outlet, the drainage gap having a drainage area and the flow regulating device comprising a number of perforations along the axial length thereof and a discharge opening in the first end which opens towards the outlet;
• and
• a position adjustment device which is connected to the flow regulating device and is configured to selectively move the flow regulating device in the axial direction to selective stationary positions to thereby adjust the drainage area of the drainage gap;
• wherein the position adjustment device comprises an external interface arranged on the outside of the container;
• and
• wherein the external interface is configured to be manipulated by an ROV manipulator or an actuator wired to a subsea control system.