Modular Compressor Gas Bearings for High-Load Production Gas Boosting

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Solution Overview

Problem

Conventional compressor designs for natural gas production face challenges in efficiently journaling heavy rotor masses due to high static and dynamic loads, particularly in subsea environments where oil lubrication is undesirable, and traditional gas bearings have limited capacity for high-power applications.

Innovation Solution

The compressor system employs gas bearings fed with production gas from internal or external infeed ports, allowing for reduced rotor mass and the use of traditional gas bearings, supplemented by non-gas bearings for transient modes, and incorporates a ring motor with permanent and electromagnet components for reduced wear and complex assembly needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If traditional gas bearings are used for journaling heavy rotor masses in high-power compressors, then the bearing structure remains simple and traditional design can be applied, but the bearing capacity is insufficient for high-power applications with larger rotor masses

Engineering Contradiction:
Improvebearing structure complexityVSAvoidbearing capacity
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The rotor is divided into multiple rotor modules (first rotor module, second rotor module, third rotor module) that can be independently supported by gas bearings. This segmentation reduces the effective mass each bearing must support while maintaining overall rotor functionality, enabling traditional gas bearing designs to handle high-power applications.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Gas is introduced as an intermediary substance between the rotor modules and bearing surfaces to create gas films that support the rotor modules. The gas bearing system uses gas pressure to suspend and support the segmented rotor modules, achieving both simple traditional bearing structure and sufficient bearing capacity for high-power applications.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If oil lubricated contact bearings are used for supporting compressor rotor, then the bearing can handle high loads, but the lubricating media becomes contaminated and lubrication-cooling property deteriorates

Engineering Contradiction:
Improvebearing load capacityVSAvoidlubrication property
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent replaces oil-lubricated contact bearings with gas bearings that use gas films for support. This substitution eliminates direct mechanical contact between bearing surfaces, preventing oil contamination while maintaining load-bearing capability through hydrodynamic gas film pressure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention uses gas (pneumatic system) instead of oil (hydraulic system) as the lubricating medium. Gas is supplied to create pressurized gas films between the rotor modules and bearing surfaces, providing both lubrication and cooling without the contamination issues associated with oil-based systems.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Object-affected harmful factors

If active magnetic bearings are used to avoid oil in subsea environment, then oil contamination is eliminated, but the system becomes complex and costly with electronic equipment and power controls

Engineering Contradiction:
Improveoil contaminationVSAvoidbearing system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent employs passive gas bearings that use gas pressure fields instead of active magnetic fields. Gas is supplied through feed passages to create supporting gas films between rotor modules and bearings, eliminating oil contamination while avoiding the electronic complexity of active magnetic bearing systems.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The gas bearing system is designed to be self-regulating through passive hydrodynamic principles. The gas films automatically form and maintain themselves based on rotor rotation and gas supply pressure, eliminating the need for electronic sensors, controllers, and power regulation systems required by active magnetic bearings.

Inventive Principle:
Principle #25Self-service

4Power

If the rotor is designed as a single heavy mass for high-power output, then the compressor can generate high pressure, but the rotor requires complex bearings and separation between bearing cavity and process

Engineering Contradiction:
Improvecompressor power outputVSAvoidbearing and sealing system complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The rotor is segmented into multiple rotor modules (first, second, and third rotor modules) that can be independently supported by gas bearings. This segmentation reduces the effective mass each bearing must support, enabling the use of simpler bearing designs while maintaining the high-power output capability of the overall compressor system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The gas bearing system serves multiple functions simultaneously: it supports the segmented rotor modules, provides lubrication without oil contamination, enables cooling through gas flow, and eliminates the need for separate sealing systems. This multi-functionality reduces overall system complexity while maintaining high-power capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design enables efficient and reliable operation of high-power compressors by utilizing gas bearings with production gas feed, minimizing structural modifications and maintaining high-pressure access, while non-gas bearings support the rotor during insufficient gas pressure conditions, ensuring stable operation and reduced maintenance.

Implementation Method 1

at least one bearing for taking up axial and/or radial load is provided to journal the rotor module on the stationary module... the at least one bearing is a gas bearing

Methodology Applied
Scientific EffectGas bearing: Air Lubrication

Implementation Method 2

a passage is arranged in the stationary module to lead an extracted portion of production gas at raised pressure from the compressor to the gas bearing(s)

Methodology Applied
Scientific EffectGas flow through passage:

Data Source

PatentEP3464907B1Modular compressor with gas bearings and system for raising the pressure in production gas
Publication Date: 2022.05.18 VETCO GRAY SCANDINAVIA
  • EP3464907B1 patent drawingFigure 1
  • EP3464907B1 patent drawingFigure 2
  • EP3464907B1 patent drawingFigure 3

AI summary

A system and modular compressor (1) for raising the pressure in production gas is disclosed, wherein in a set of compressor modules each second module is a rotor module (4) carrying an impeller (5) driven in rotation relative to an adjacent stationary module (6), a rotor module and a stationary module in combination providing a compressor stage in which production gas is accelerated through a flow duct (7) that passes an interface (8) between the rotor module and the stationary module, wherein at said interface at least one bearing for axial and/or radial load is provided for journaling the rotor module on the stationary module. The at least one bearing is a gas bearing (15, 15 ', 34), wherein a passage (24; 27) is arranged in the stationary module (6) to lead an extracted portion of production gas at raised pressure from the compressor (1) to the gas bearing(s) (15, 15', 34).