Process Fluid Pump with Balance Drums for Subsea Seawater Injection
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Solution Overview
Problem
Conventional process fluid lubricated pumps for seawater injection in the oil and gas industry face challenges in subsea applications due to complexity, wear, and reliability issues, particularly in deep water environments where maintenance is difficult and equipment minimization is crucial.
Innovation Solution
A process fluid lubricated pump design featuring a common housing with a pump unit and drive unit, incorporating balance drums at both ends of the pump shaft to enhance rotor stability, reduce wear, and minimize equipment complexity, allowing for a single pump to serve both as a feed pump and water injection pump, eliminating the need for separate units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional process fluid lubricated pumps are used for subsea seawater injection, then the pump can convey process fluid, but the equipment complexity increases and reliability decreases due to wear and maintenance requirements
Solution Approach 1:
The patent combines the feed pump and water injection pump into a single integrated pump unit. The common housing contains both pump stages sharing a common drive mechanism and process fluid lubrication system, reducing the number of separate equipment components and eliminating the need for multiple seals and bearing assemblies that would otherwise be required in separate pumps
Solution Approach 2:
The single pump unit performs multiple functions: it acts as both a feed pump for nanofiltration and a high-pressure water injection pump. The common drive mechanism drives both pump stages, and the process fluid serves multiple purposes including lubrication for both stages and sealing, eliminating the need for separate lubrication systems for each pump
2Reliability
If conventional pump designs are used, then the pump can operate, but wear increases and maintenance requirements increase due to lack of adequate lubrication
Solution Approach 1:
The pump system uses the process fluid (seawater) to lubricate and cool the bearing assemblies and drive mechanism. The process fluid circulates through channels in the common housing and pump components, providing continuous lubrication without requiring external lubrication systems or seals that would need maintenance. The process fluid itself serves the lubrication function, eliminating the need for separate lubricant supply and management systems
Solution Approach 2:
The patent extracts the lubrication function from a separate lubrication system and integrates it into the process fluid flow. The process fluid is diverted through lubrication channels in the bearing assemblies and drive mechanism, allowing the process fluid to directly perform the lubrication function without requiring separate lubricants or complex lubrication management systems
3Productivity
If separate feed pump and water injection pump are used, then each pump can be optimized for its function, but the system complexity increases and space requirements increase
Solution Approach 1:
The patent merges the feed pump and water injection pump into a single integrated unit with a common housing, shared drive mechanism, and common process fluid lubrication system. The first pump stage handles feed pumping for nanofiltration while the second stage handles high-pressure water injection, both driven by a single motor and lubricated by the same process fluid circulation system
Solution Approach 2:
The single pump unit is designed to perform both feed pumping and high-pressure injection functions. The common drive mechanism can be optimized to provide appropriate torque and speed for both stages, and the process fluid lubrication system serves both pump stages simultaneously, allowing the system to maintain high productivity while reducing equipment count
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design improves rotor stability, reduces wear and failure risk, and simplifies the system by integrating functions, thereby enhancing reliability and reducing the complexity and cost of subsea seawater injection systems.
Implementation Method 1
The process fluid is circulated through the drive unit and pump unit to cool the bearing assemblies and motor
Implementation Method 2
The process fluid is circulated through the drive unit and pump unit to cool the bearing assemblies and motor
Data Source
AI summary
A process fluid lubricated pump includes a pump having a pump shaft extending from a drive end to a non-drive end to rotate about an axial direction, a first pump section having a first set of impellers fixedly mounted on the pump shaft to increase the pressure of the process fluid, a drive to exert a torque on the drive end of the pump shaft to drive the rotation of the pump shaft, a first balance drum fixedly connected to the pump shaft between the pump and the drive end of the pump shaft, the first balance drum defining a first front side facing the pump and a first back side, and a second balance drum fixedly connected to the pump shaft between the pump and the non-drive end of the pump shaft, the second balance drum defining a second front side facing the pump and a second back side.