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BR-102020017390-B1 - MULTIPHASE PUMP

BR102020017390B1BR 102020017390 B1BR102020017390 B1BR 102020017390B1BR-102020017390-B1

Abstract

Multiphase pump. The present invention relates to a multiphase pump for transporting a multiphase process fluid, comprising a pump housing (2) with a pump inlet (21) and a pump outlet (22), a rotor (3) disposed in the pump housing (2) and configured to rotate about an axial direction (A), and at least one radial bearing (53, 54) having a support carrier (58) and a support structure (57) to support the rotor (3) in relation to a radial direction perpendicular to the axial direction (A), wherein the rotor (3) comprises a pump shaft (5) and at least one impeller (31) fixedly mounted on the pump shaft (5) to transport the process fluid from the pump inlet (21) to the pump outlet (22), wherein a damping compression film (10) is provided to reduce the vibrations of the rotor (3), wherein the damping compression film (10) is disposed around of the support structure (57) of the radial bearing (53, 54), in which the damping compression film (10) has a radially external surface (101), in which a damping gap (12) is created at a location between the support structure (57) of the radial bearing (53, 54) and the radially external surface (101) of the damping compression film, and in (...).

Inventors

  • Karel DE RAEVE
  • Marco Carvalho
  • Thomas Welschinger

Assignees

  • SULZER MANAGEMENT AG

Dates

Publication Date
20260317
Application Date
20200826
Priority Date
20191025

Claims (14)

  1. 1. Multiphase pump for conveying a multiphase process fluid, comprising: a pump housing (2) with a pump inlet (21) and a pump outlet (22), a rotor (3) disposed in the pump housing (2) and configured to rotate around an axial direction (A); and at least one radial bearing (53, 54) having a support carrier (58) and a support structure (57) to support the rotor (3) with respect to a radial direction perpendicular to the axial direction (A), wherein the rotor (3) comprises a pump shaft (5) and at least one impeller (31) fixedly mounted on the pump shaft (5) to transport the process fluid from the pump inlet (21) to the pump outlet (22), characterized in that a damping compression film (10) is provided to reduce the vibrations of the rotor (3), wherein the damping compression film (10) is arranged around the support structure (57) of the radial bearing (53, 54), wherein the damping compression film (10) has a radially external surface (101), in which a damping gap (12) is created at a location between the support structure (57) of the radial bearing (53, 54) and the radially outer surface (101) of the damping compression film and in which the damping gap (12) is configured to receive a damping fluid, wherein the pump is configured as a helical-axial pump with helical-axial impellers (31), and the radial bearing (53, 54) is configured as a swaying shoe bearing, the support carrier (58) being a shoe carrier of the swaying shoe bearing, and the support structure (571) comprises a plurality of shoes with each of the plurality of shoes being mounted on the shoe carrier in such a way as to allow the oscillating movement of each shoe of the plurality of shoes.
  2. 2. Multiphase pump, according to claim 1, characterized in that the radial bearing is a first radial bearing of a plurality of radial bearings (53, 54), the plurality of radial bearings (53, 54) comprising at least one second radial bearing, the second radial bearing comprising a support carrier (58) and a support structure (57) for supporting the rotor (3) with respect to the radial direction, such that for the second radial bearing (54) a damping compression film (10) is provided, which is disposed around the support structure (57) of the second radial bearing (53, 54) and a damping gap (12) configured to receive a damping fluid is disposed between the support structure (57) of the second radial bearing and a radially external surface (101) of the damping compression film (10) for the second radial bearing (54), the second radial bearing (54) is a rocking shoe bearing, wherein the support carrier (58) of the second radial bearing (54) is a shoe carrier of the second radial bearing (54) and the support structure of the second radial bearing comprises a plurality of shoes with each of the shoes mounted on the shoe carrier of the second radial bearing in order to allow rocking motion of each shoe of the plurality of shoes of the second radial bearing.
  3. 3. Multiphase pump, according to claim 1, characterized in that at least one impeller (31) comprises a plurality of impellers.
  4. 4. Multiphase pump, according to claim 2, characterized in that each damping compression film (10) for each of the first and second radial bearings (53, 54) is arranged around a support carrier (58).
  5. 5. Multiphase pump, according to claim 1, characterized in that the damping compression film (10) for the radial bearings (53, 54) is the only damping compression film and is integrated into the particular radial bearing (53, 54)).
  6. 6. Multiphase pump, according to claim 1, characterized in that each radial bearing (53, 54) is configured to receive a lubricant to lubricate the radial bearing (53, 54), and each damping gap (12) is configured to receive the lubricant as damping fluid.
  7. 7. Multiphase pump, according to claim 1, characterized by also comprising a drive unit (4) disposed in the pump housing (2) and configured to drive the rotor (3).
  8. 8. Multiphase pump, according to claim 7, characterized in that the drive unit (4) comprises a shaft drive (42) for driving the pump shaft (5) of the rotor (3), and an electric motor (41) for rotating the shaft drive (42) around the axial direction (A), and that a coupling (8) is provided for coupling the shaft drive (42) to the pump shaft (5).
  9. 9. Multiphase pump, according to claim 1, characterized in that it is configured as a vertical pump with the pump shaft (5) extending in the direction of gravity.
  10. 10. Multiphase pump, according to claim 7, characterized in that the drive unit (4) is arranged on top of the pump shaft (5).
  11. 11. Multiphase pump, according to claim 1, characterized in that it is configured as a horizontal pump with the pump shaft (5) extending perpendicular to the direction of gravity.
  12. 12. Multiphase pump, according to claim 1, characterized in that it is configured as a submersible pump.
  13. 13. Multiphase pump, according to claim 1, characterized in that it is configured to transport multiphase process fluids with a gas volume fraction of 0% to 100%.
  14. 14. Multiphase pump, according to claim 1, characterized in that the pump is configured to be installed on the seabed.

Description

[001] The present invention relates to a multiphase pump for transporting a multiphase process fluid according to the preamble of the independent claim. [002] Multiphase pumps are used in several different industries where it is necessary to transport a multiphase process fluid comprising a mixture of a plurality of phases, for example, a liquid phase and a gaseous phase. An important example is the oil and gas processing industry where multiphase pumps are used to transport hydrocarbon fluids, for example, to extract crude oil from the oil field or to transport oil/gas through pipelines or into refineries. [003] Fossil fuels are generally not present in pure form in oil or natural gas fields, but rather as a multiphase mixture containing liquid components, gaseous components, and probably solid components as well. Such a multiphase mixture, composed, for example, of crude oil, natural gas, chemicals, seawater, and sand, has to be pumped out of the oil or natural gas field. For such transport of fossil fuels, multiphase pumps are used that are capable of pumping a liquid-gas mixture that may also contain solid components, such as, for example, sand. [004] One of the challenges in designing multiphase pumps is the fact that in many applications the composition of the multiphase process fluid is extremely variable during pump operation. For example, during oil field exploration, the ratio of the gaseous phase (e.g., natural gas) to the liquid phase (e.g., crude oil) is extremely variable. These variations can occur suddenly and cause a drop in pump efficiency, pump vibrations, or other problems. The proportion of the gaseous phase in the multiphase mixture is commonly measured by the gas volume fraction (GVF), which designates the volume proportion of gas in the multiphase process fluid. In oil and gas industry applications, the GVF can range from 0% to 100%. [005] Currently, with a view to efficient oil and gas field exploration, there is a growing demand for pumps that can be installed directly on the seabed, in particular at depths of 500 m, 1000 m or even more than 2000 m below the water surface. Needless to say, the design of such pumps is a challenge, mainly because these pumps need to operate in a harsh underwater environment for a long period with minimal maintenance and servicing. This condition requires specific measures to minimize the amount of equipment involved and to optimize pump safety. [006] It is well known in the art that multiphase pumps are prone to rotor vibrations. The pump rotor comprises a pump shaft and one or more impellers attached to the pump shaft in a torque-proof manner. There are several reasons why rotor vibrations are a problem, particularly in multiphase pumps. A typical single-phase centrifugal pump has a significant amount of internal damping due to leakage of single-phase process fluid through internal seals or gaps along the pump rotor. Examples of such seals or gaps are the impeller eye seal, the impeller hub seal, wear rings, regulating bushings, and the balance drum. The leakage flow of process fluid through these seals or gaps neutralizes the vibrations and generates rotor damping. The physical phenomenon on which this damping is based is the Lomakin effect. The Lomakin effect is a force created in small gaps, for example, in wear rings, regulating bushings, or balancing devices in centrifugal pumps. The force results from an uneven pressure distribution around the circumference of the pump shaft during periods of rotor eccentricity or pump shaft deflection. Due to rotor eccentricity, the gap, i.e., the space between the rotor and the stationary part surrounding the rotor, is larger on one side of the rotor than on the other side, resulting in differences in the local fluid velocity. The local fluid velocity is higher in these locations where the gap is larger. A higher local velocity causes a lower pressure, and a lower local velocity causes a higher pressure. This condition creates a resultant corrective force, which always acts in the opposite direction to the shaft deflection or eccentricity. Thus, the Lomakin effect supports the centering of the pump shaft and thereby generates rotor damping. [007] A multiphase pump can be designed to transport multiphase process fluids that have a GVF from 0% to 100%, i.e., all process fluids from a pure liquid (GVF = 0%) to a pure gas (GVF = 100%). At high GVF values, the pressure rise generated by the multiphase pump is significantly lower than at low GVF values. A multiphase pump, which is, for example, configured with helical-axial impellers, typically has only the balance drum and diffuser gaps as spaces. These spaces are designed to allow leakage of a liquid and are therefore considerably large for applications or operating conditions with high GVFs. Thus, the problem with multiphase pumps is that, under operating conditions with high GVF values, the rotor damping generated by the Lomakin effect is very small, since the