Pump Protection via Master Torque Curve and Differential Pressure
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Solution Overview
Problem
Conventional methods for protecting hydrocarbon pumps from excessive flow rates require expensive multiphase flow meters to measure gas volume fraction and flow rate, which is impractical and costly, especially in subsea operations.
Innovation Solution
Establishing a master maximum torque curve based on differential pressure across the pump, which represents the maximum torque limit for all gas volume fractions, allowing for monitoring and regulation of pump torque without needing to measure gas volume fraction or flow rate, thereby protecting the pump from high flow regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional flow meters are used to detect maximum flow conditions, then accurate flow rate measurement is achieved, but system cost increases significantly
Solution Approach 1:
The invention extracts the essential protective function from complex flow measurement systems. Instead of using expensive multiphase flow meters to measure both flow rate and gas volume fraction, the patent extracts only the necessary protective function by using a single pressure sensor combined with pump performance characteristics to detect high flow conditions, thereby eliminating unnecessary measurement complexity while maintaining protection capability
Solution Approach 2:
The invention creates a virtual model of pump performance by establishing performance curves that represent the relationship between pressure differential, flow rate, and power consumption. This virtual model allows the system to infer flow conditions without physical flow meters, effectively copying the essential information needed for protection in a much simpler and cheaper form
2Measurement precision
If multiphase flow meters are used to measure gas volume fraction and flow rate, then accurate detection of high flow conditions is achieved, but operational cost increases
Solution Approach 1:
The system uses the pump's own performance characteristics and readily available pressure measurements to self-diagnose high flow conditions. The pump essentially monitors itself by comparing actual operating points against predetermined performance curves, eliminating the need for expensive external measurement devices and reducing operational costs
3Reliability
If torque limits are established for each gas volume fraction value, then accurate pump protection is achieved, but system complexity increases
Solution Approach 1:
The invention creates a universal protection approach that works across all gas volume fraction conditions. By establishing a master torque curve that encompasses all GVF scenarios, the system provides universal protection without needing to manage multiple specific curves for different gas fractions, making the protection system both robust and simple
Data Source
AI summary
Protecting a hydrocarbon pump from excessive flow rates in a hydrocarbon fluid system comprising an electrical motor for driving the pump. For each of a plurality of gas volume fraction values of the hydrocarbon fluid, establishing a maximum torque limit for the pump by mapping the maximum allowable torque of the pump as a function of the differential pressure, thereby creating a plurality of maximum torque curves, each representing the maximum torque limit for a unique gas volume fraction value. Establishing a master maximum torque curve which represents the maximum torque limit for all gas volume fraction values. Monitoring the torque of the pump and the differential pressure across the pump. Based on the monitored differential pressure and using the master maximum torque curve, establishing a maximum allowable torque for the pump. Taking action if the monitored torque exceeds the established maximum allowable torque.