Subsea Multiphase Pump Lubrication via Separator Liquid
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Solution Overview
Problem
Twin screw pumps used in subsea oil and gas extraction face challenges with lubrication systems that require additional components and maintenance, particularly when pumping multiphase fluids, as existing systems either lack a lubricant reservoir or do not incorporate solid-liquid separation devices.
Innovation Solution
A subsea system that includes a multiphase separator with solid-liquid and gas-liquid separation devices, along with a liquid reservoir to utilize the separated liquid phase as a lubricant for the pump, reducing the need for external lubricant supply and enhancing maintenance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lubricant flush system is used to lubricate and cool the bearings and timing gears, then the lubrication and cooling function is improved, but the device complexity and maintenance requirements increase
Solution Approach 1:
The patent combines the lubrication and cooling functions with the existing multiphase fluid handling system. The separated liquid phase from the multiphase fluid is reused as lubricant, merging the fluid separation process with the lubrication system, thereby eliminating the need for separate lubricant reservoirs and flush systems while maintaining reliable lubrication and cooling of bearings and timing gears
Solution Approach 2:
The system uses its own processed liquid phase to lubricate and cool its own components. The multiphase separator produces a liquid phase that is automatically routed back to lubricate the pump bearings and timing gears, creating a self-sufficient lubrication system that reduces external dependencies and maintenance requirements
2Reliability
If a shaft seal with lubricant flush system is used, then the sealing reliability is improved, but the maintenance costs and operational complexity increase
Solution Approach 1:
The shaft seal system is integrated with the self-service lubrication approach where the separated liquid phase continuously flushes and lubricates the seal surfaces. This eliminates the need for external lubricant supply systems and reduces maintenance intervention, as the system automatically maintains its own sealing components using its own processed fluid
3Reliability
If an external lubricant supply system is implemented, then the lubrication reliability is improved, but the device complexity and cost increase
Solution Approach 1:
The system eliminates external lubricant supply by using its own separated liquid phase as the lubricant source. The multiphase separator naturally produces a liquid phase that is routed through the pump, providing continuous lubrication to bearings and timing gears without requiring external reservoirs, pumps, or supply lines
Solution Approach 2:
The liquid phase from the multiphase separator serves multiple functions: it acts as the pumped fluid medium, provides lubrication for mechanical components, and offers cooling for bearings and timing gears. This multi-functionality eliminates the need for separate lubricant supply systems and reduces overall system complexity
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
This solution simplifies the lubrication system by utilizing the separated liquid phase from the multiphase fluid for pump components, reducing downtime and wear, and eliminating the need for an external lubricant supply, thus enhancing the reliability and cost-effectiveness of the twin screw pump operation.
Implementation Method 1
a solid-liquid separation device configured to facilitate separation of the solid phase and the liquid phase from the multiphase fluid
Implementation Method 2
separation of the solid phase and the liquid phase from the multiphase fluid
Implementation Method 3
a gas-liquid separation device configured to facilitate separation of the gaseous phase and the liquid phase from the multiphase fluid
Implementation Method 4
The liquid reservoir is configured to contain a volume of the liquid phase to be used as a lubricant for the multiphase pump
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A subsea system includes a multiphase pump, configured to transfer a multiphase fluid and a multiphase separator, configured to separate the multiphase fluid into solid, liquid, and gaseous phases. The multiphase separator includes a solid-liquid separation device, which is configured to facilitate separation of the solid phase and the liquid phase from the multiphase fluid. The multiphase separator includes a gas-liquid separation device, which is configured to facilitate separation of the gaseous phase and the liquid phase from the multiphase fluid. The multiphase separator includes a liquid reservoir, which is configured to contain a volume of the liquid phase to be used as a lubricant for the multiphase pump. Finally, the multiphase separator includes a liquid outlet, which is configured to transfer the liquid phase from the liquid reservoir to the multiphase pump.