Abstract: A method and system for actively controlling an axial separation between a seal face of a stationary ring and a seal face of a rotating ring of a gas seal is disclosed. At least one property is sensed indicative of a condition of at least one of the seal faces. With at least one sensing device, a characteristic of the axial separation between the seal faces is sensed. A net magnetic force of at least one magnetic device is adjusted based on the property and/or the characteristic. Adjusting the net magnetic force adjusts the axial separation between the seal faces. Without using a buffer gas between the seal faces, flow of gas or other fluid is controlled between the seal faces by adjusting the axial separation.

Abstract: The disclosure includes controlling a pressure ratio for a compressing system, comprising introducing a quantity of liquid into an input stream to create a multiphase input stream, compressing the multiphase input stream with a centrifugal compressor to create a discharge stream, measuring a parameter of the discharge stream, wherein the discharge parameter corresponds to a pressure ratio for the centrifugal compressor, when the parameter exceeds a first predetermined point, increasing a pressure ratio of the centrifugal compressor by increasing the quantity of liquid introduced, and when the parameter exceeds a second predetermined point, decreasing the pressure ratio by decreasing the quantity of liquid introduced.