Centrifugal Compressor Liquid Injection for Wet Gas
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Solution Overview
Problem
Centrifugal compressors and gas expanders face limitations in handling high liquid content multiphase flows, leading to instability, erosion, fouling, and slugging, requiring expensive and complex liquid separation systems that are bulky and prone to failure.
Innovation Solution
The technique involves intentionally injecting liquid into the compressor system to alter the operating conditions, using thermodynamic and aerodynamic effects to increase pressure ratio and reduce droplet size, thereby enhancing the compressor's ability to handle higher liquid fractions and prevent slugging, by atomizing the liquid into smaller droplets and controlling the liquid fraction to extend the surge range and reduce erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid separators, dehydration processes and scrubbers are used to remove liquids prior to compression, then the compressor can operate with lower liquid content, but the equipment becomes expensive, complex and bulky
Solution Approach 1:
The invention extracts and removes the complex liquid separation system (separators, dehydration processes, scrubbers) from the conventional compression train. By injecting liquid into the compressor inlet, the system eliminates the need for these separate liquid removal devices, thereby reducing overall system complexity while maintaining reliable operation.
Solution Approach 2:
The compressor is transformed from a device that requires pre-treatment for liquid removal into a multiphase capable device. The liquid injection system enables the compressor to handle both gas and liquid phases simultaneously, making it a universal device that performs compression while managing liquid content without requiring separate separation equipment.
2Reliability
If liquid separators are designed for specific operating conditions, then they can effectively separate liquids at those conditions, but they are limited in the range of Gas Volume Fraction (GVF) that can be handled
Solution Approach 1:
The system dynamically adjusts liquid injection rates based on actual operating conditions and GVF variations. The liquid injection system can adapt to different gas flow rates and liquid content levels, enabling the compressor to handle a wide range of GVF values while maintaining effective liquid management throughout the operating range.
3Stability of the object's composition
If centrifugal compressors are restricted to applications with GVFs of 99.7 or higher, then machine stability is maintained, but the compressor cannot handle higher liquid fractions without causing slugging and damage
Solution Approach 1:
The liquid injection system applies preliminary anti-action by intentionally introducing liquid into the compressor inlet before compression. This pre-introduced liquid prevents the formation of harmful liquid slugs during compression by maintaining a controlled liquid distribution throughout the compression process, thereby preventing slugging and erosion damage while allowing higher liquid fractions to be handled.
4Reliability
If expensive liquid separation equipment is used to remove liquids, then the compressor can operate with lower liquid content, but the equipment takes up expensive real estate and adds to system complexity
Solution Approach 1:
The invention extracts and eliminates the bulky liquid separation equipment (separators, scrubbers, dehydration units) from the system. By implementing liquid injection directly at the compressor inlet, the solution removes the need for separate liquid removal devices, thereby reducing the overall equipment footprint and eliminating the expensive real estate requirement while maintaining reliable compressor operation.
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 approach allows centrifugal compressors to operate more efficiently and stably at higher liquid fractions, reducing the need for expensive separation equipment, mitigating slugging and erosion, and extending the compressor's operational range without causing surge phenomena, while minimizing the risk of liquid carry-over and damage to components.
Implementation Method 1
using thermodynamic and aerodynamic effects to increase pressure ratio and reduce droplet size, thereby enhancing the compressor's ability to handle higher liquid fractions
Implementation Method 2
centrifugal compressors or gas expanders do not handle liquid slugs and thus it is assumed that they can only handle a fraction of one percent liquid by volume
Data Source
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AI summary
The disclosure includes a centrifugal compressor, comprising an inlet configured to receive a gas stream, an outlet, and a liquid injection port configured to introduce a liquid into the gas stream and create a multiphase fluid, wherein the centrifugal compressor is configured to compress the multiphase fluid. The disclosure further includes a method of operating a centrifugal compressor, comprising passing a gas stream to a centrifugal compressor inlet, introducing a quantity of liquid into the gas stream to create a multiphase stream, and compressing the multiphase stream.