Abstract: A system for dewatering a subsea gas pipeline includes a pig launcher at the pipeline's upper end, which may be at or near the sea surface, and a pig receiver at the pipeline's lower end, which may be at or near the sea floor. A multiphase pump unit is deployed at the pipeline lower end and is configured to provide sea water suction to aid in a pig train being forced downwards through pipeline. The multiphase pump is configured to handle some amount of gas leaking around the pig train. A choke system may allow sea water to enter the flowline, thereby lowering the gas volume fraction (GVF) and preventing the GVF from exceeding the ability of the multiphase pump. For deeper water applications, a second pump may be provided in series that may be a single pump if positioned downstream of the multiphase pump.

Abstract: A system for dewatering a subsea gas pipeline includes a pig launcher at the pipeline's upper end, which may be at or near the sea surface, and a pig receiver at the pipeline's lower end, which may be at or near the sea floor. A multiphase pump unit is deployed at the pipeline lower end and is configured to provide sea water suction to aid in a pig train being forced downwards through pipeline. The multiphase pump is configured to handle some amount of gas leaking around the pig train. A choke system may allow sea water to enter the flowline, thereby lowering the gas volume fraction (GVF) and preventing the GVF from exceeding the ability of the multiphase pump. For deeper water applications, a second pump may be provided in series that may be a single pump if positioned downstream of the multiphase pump.

Abstract: A flowline dewatering system comprising at least one pump and a pig train supported by a gas pressure enabling suction conditions for the pump. A method to dewater a flowline using the system.

Abstract: A diffuser for a fluid compression device includes at least one vane mounted on a hub. The at least vane includes at least one opening (5) starting at a distance ranging between 10% and 60% of the axial length of the vane. The diffuser can be used in a fluid compression device also including a housing, at least one impeller within the housing, the impeller including at least one vane, the diffuser being arranged within the housing, upstream or downstream from said impeller.

Abstract: The present disclosure describes a diffuser (2) for a fluid compression device, comprising at least one vane (4) mounted on a hub. In embodiments of the disclosure, at least one opening (5) is provided in the diffuser vanes (4), in the radial direction.