Pressure boosting system for multi-phase crude oil

A method for pumping a feed mixture, comprising:

• feeding the feed mixture into a separation tank of a pressure boosting system via a feed mixture entrance;
• separating the feed mixture into a gas and a liquid in the separation tank;
• passing the liquid through a liquid outlet, wherein the liquid outlet is located at lower position from the feed mixture entrance along a wall of the separation tank;
• controlling flow of the liquid through the liquid line using a flow control valve positioned along the liquid line;
• passing the gas through a gas line extending through the separation tank from a gas inlet located in an interior of the separation tank to a gas outlet located outside of the separation tank;
• simultaneously flowing gas through the gas outlet and flowing the liquid from the liquid outlet through a liquid line to a fluid suction chamber surrounding the gas outlet to mix the liquid and the gas into a mixed fluid;
• and
• flowing the mixed fluid through a diffuser to a pump.