Centrifugal Compressor with Permanent Magnet Motor for PSA Gas Separation

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Solution Overview

Problem

Conventional PSA and VPSA processes face inefficiencies due to high power consumption and structural damage from pressure pulsations caused by rotary-lobe blowers, and fixed-speed centrifugal compressors struggle to adapt to dynamic pressure swing cycles, leading to suboptimal energy use and maintenance challenges.

Innovation Solution

The implementation of high-speed permanent magnet motors with variable-speed control for centrifugal compressors, eliminating the need for gearboxes and lube oil systems, allows for rapid acceleration and deceleration, enabling operation along the best efficiency line and reducing power consumption by over 7 percentage points compared to conventional induction motor/gearbox systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If rotary-lobe blowers are used for gas pressurization or evacuation in PSA/VPSA systems, then the equipment can adapt to oscillating pressure swing cycles, but pressure pulsations are generated that cause structural damage to downstream process equipment

Engineering Contradiction:
Improveadaptability to pressure swing cyclesVSAvoidpressure pulsations
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the harmful pressure pulsations generated by rotary-lobe blowers through the installation of pulsation dampeners and surge tanks. These devices isolate and absorb the pressure fluctuations, preventing them from propagating to downstream equipment while allowing the blowers to continue operating in the oscillating pressure swing cycles required by PSA/VPSA processes.

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If fixed-speed centrifugal compressors are used in PSA/VPSA systems, then the equipment can provide continuous gas flow, but the compressors cannot adapt to dynamic pressure swing cycles, leading to suboptimal energy use

Engineering Contradiction:
Improvecontinuous gas flowVSAvoidenergy efficiency
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent transitions from fixed-speed centrifugal compressors to variable-speed centrifugal compressors that can dynamically adjust their operating speed to match the instantaneous pressure requirements of the PSA/VPSA cycle. This dynamic speed adjustment allows the compressors to operate at optimal efficiency points across varying load conditions while maintaining continuous gas flow delivery.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operating parameters of the centrifugal compressors by implementing variable frequency drives (VFDs) that allow continuous adjustment of rotational speed. This parameter change enables the compressors to adapt to dynamic pressure swing cycles, optimizing energy efficiency across different operating conditions while maintaining productive gas flow.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional induction motor/gearbox systems are used to drive centrifugal compressors, then the equipment can provide reliable operation, but power consumption is high and maintenance is required for gear and bearing oil systems

Engineering Contradiction:
Improveoperational reliabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent replaces the conventional induction motor/gearbox mechanical drive system with a direct-drive centrifugal compressor design. This substitution eliminates the intermediate gearbox and associated lubrication systems, reducing mechanical losses and power consumption while maintaining operational reliability through simplified mechanics and fewer moving parts.

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

Solution Approach 2:

The patent extracts and removes the gearbox and lube oil system from the conventional motor-driven compressor configuration. By eliminating these components, the system reduces power consumption associated with gear friction and bearing lubrication, while direct-drive motors provide sufficient torque and reliability for the application.

Inventive Principle:
Principle #2Taking out (Extraction)

4Stress or pressure

If rotary-lobe blowers are used to meet system pressure requirements, then the equipment can handle varying pressure demands, but power consumption is proportional to system pressure differential, leading to high energy use

Engineering Contradiction:
Improvepressure differential handlingVSAvoidpower consumption
Core Design Contradiction:
Stress or pressureVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic speed control of centrifugal compressors that allows the equipment to handle varying pressure demands efficiently. By continuously adjusting the compressor speed to match instantaneous pressure requirements, the system avoids the linear power consumption relationship of rotary-lobe blowers and maintains optimal energy efficiency across different pressure differential conditions.

Inventive Principle:
Principle #15Dynamics

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 significantly improves the efficiency and adaptability of centrifugal compressors in PSA and VPSA systems, reducing power consumption and maintaining equipment integrity by enabling rapid speed adjustments and eliminating gear and bearing oil friction losses, thus enhancing overall process efficiency and reducing maintenance needs.

Implementation Method 1

a permanent magnet rotor assembly (14) having a plurality of permanent magnets (16) disposed thereon and cooperatively arranged with the stator windings (12) to provide motor action

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Implementation Method 2

centrifugal compressor with high-speed permanent magnet motor

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2285469B1System and method for PSA gas separation using centrifugal compressor with high-speed permanent magnet motor
Publication Date: 2015.01.07 PRAXAIR TECH INC
  • EP2285469B1 patent drawingFigure 1
  • EP2285469B1 patent drawingFigure 2
  • EP2285469B1 patent drawingFigure 3

AI summary

Systems and processes are provided for gas separation using high-speed permanent magnet variable-speed motors to accelerate and decelerate centrifugal compressors suitable for use in pressure swing adsorption (PSA) or vacuum pressure swing adsorption (VPSA) processes.