Multiphase Screw Pump Discharge Casing for Gas-Liquid Separation
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Solution Overview
Problem
Conventional multiphase pumps require large casings and complex, expensive designs to handle high gas concentrations, leading to reduced efficiency and increased costs, especially when dealing with high pressures and varying flow rates.
Innovation Solution
A multiphase pump system with a discharge casing oriented at an angle to the pump body, allowing for independent length adjustment and enhanced liquid recirculation, featuring angled inlets and orifices for efficient liquid distribution and separation, and capacity reduction mechanisms to maintain performance without energy waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional multiphase pumps are designed to handle high gas concentrations (50-95% gas content), then the pump capacity and flow range can be increased, but the casing size becomes very large and the design becomes complex and expensive
Solution Approach 1:
The pump system is divided into separate functional components: a standard-sized pump body for fluid pumping and an external separator vessel for gas-liquid separation. This segmentation allows the pump casing to remain compact while the separator handles the gas concentration management, resolving the contradiction between pump capacity and casing complexity.
Solution Approach 2:
The separation function is moved from the traditional radial dimension (within the pump casing) to an external vertical dimension (separate separator vessel). This dimensional relocation allows the pump body to maintain standard dimensions while the separator provides the necessary gas handling capacity externally.
2Reliability
If the pump casing is enlarged to create a liquid reservoir for separation and recirculation, then liquid can be provided to screw inlets and outlets for sealing and heat removal, but the casing diameter increases and cost increases
Solution Approach 1:
The liquid reservoir and separation functions are extracted from the pump casing and placed in an external separator vessel. This extraction allows the pump casing to maintain a standard, compact diameter while the external separator provides the necessary liquid reservoir capacity for sealing and heat removal functions.
Solution Approach 2:
An external separator vessel acts as an intermediary between the pump and the fluid source. It provides the liquid reservoir function externally, using recirculation lines to supply liquid to the screw inlets and outlets, thereby maintaining reliable sealing without enlarging the pump casing.
3Stress or pressure
If pressure rating is increased to 100 barg or 150 barg to handle wellhead-shut-in pressures, then the pump can withstand high pressures, but the casing thickness and material requirements increase cost
Solution Approach 1:
The high-pressure containment function is extracted from the pump casing to a separate pressure-rated shell around the separator. This allows the pump body to be manufactured at standard pressure ratings (reducing cost) while the external shell provides the necessary 100-150 barg pressure containment capability.
Solution Approach 2:
The pressure containment system is segmented into two parts: the pump body at standard pressure rating and an external pressure shell at high pressure rating. This segmentation allows each component to be optimized independently, reducing overall manufacturing cost while maintaining high-pressure capability.
4Ease of operation
If an oversized integrated discharge casing is used as separator and liquid reservoir, then liquid recirculation can be achieved, but the device complexity and cost increase
Solution Approach 1:
The separation and recirculation functions are extracted from the integrated discharge casing and placed in an external separator vessel. This extraction simplifies the pump casing design to standard components while the external separator provides the liquid recirculation capability through dedicated recirculation lines and control mechanisms.
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 system achieves reduced casing diameter, lower complexity, and cost-effective operation with improved efficiency and performance, even under high gas concentrations, by optimizing liquid recirculation and separation, and reducing pump capacity without energy loss.
Implementation Method 1
The discharge casing can include a separation chamber that facilitates separation of liquid and gas components of the fluid discharged from the first and second screw rotors
Data Source
AI summary
A multiphase pump system includes a pump (10) having first and second screw rotors (4) disposed within a pump body (A), and at least one inlet (3) in fluid communication with the first and second screw rotors, respectively. A discharge casing (B) is coupled to the pump body (A) for receiving fluid discharged from the first and second screw rotors (4). The discharge casing (B) is oriented orthogonally or at a non-zero angle with respect to a longitudinal axis of the pump body (A). The discharge casing (B) includes a separation chamber for separating liquid and gas components of the fluid discharged from the first and second screw rotors (4). The pump body (A) includes at least one opening (9) for directing separated liquid from the discharge casing (B) to a discharge chamber of the pump body (A).