Residue Stream Expansion for Argon Recovery and Net Power Generation
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Solution Overview
Problem
Power plants lose valuable nitrogen and argon from the high-pressure residue stream after CO2 capture, as this stream is vented to the atmosphere, rather than being utilized for power generation and argon recovery.
Innovation Solution
The high-pressure residue stream is purified and expanded through turbines to generate power and refrigeration, then processed in a distillation column system for separation, allowing for the recovery of nitrogen, oxygen, and argon without external cooling, thereby producing a net positive energy environment for argon production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the high-pressure residue stream is vented to the atmosphere, then the CO2 capture process is simple to operate, but valuable nitrogen and argon are lost and no additional power is generated
Solution Approach 1:
The patent recovers valuable nitrogen and argon from the residue stream that would otherwise be discarded. The system separates and recovers these components through distillation columns, converting waste material into useful products and preventing loss of valuable substances.
Solution Approach 2:
The residue stream utilization system serves multiple functions: generating power through turbines, recovering valuable gases (nitrogen and argon), and providing refrigeration for the CO2 capture process. This multi-functionality addresses the complexity concern by demonstrating that a single integrated system can achieve multiple benefits simultaneously.
2Quantity of substance
If traditional air separation is used to produce argon, then argon production is achieved, but the cost is high and energy consumption is high
Solution Approach 1:
The system performs preliminary separation of CO2 from the residue stream before argon production. By removing CO2 and other impurities upfront through the purification system, the subsequent distillation process requires less energy and can produce argon more efficiently than traditional air separation methods.
Solution Approach 2:
The patent changes the composition parameters of the feed stream by removing CO2 and adjusting the nitrogen-to-argon ratio through preliminary purification. This parameter modification creates a more favorable feed composition for distillation, reducing energy consumption and improving argon production efficiency compared to processing raw air.
3Power
If the residue stream is expanded in turbines to generate power, then additional power is produced, but the stream pressure decreases and refrigeration capacity is reduced
Solution Approach 1:
The residue stream is divided into multiple portions that are expanded in separate turbine stages. The first expansion generates power while the second expansion provides refrigeration. This segmentation allows the system to optimize each expansion stage for its specific purpose, maintaining both power generation and refrigeration capabilities.
Solution Approach 2:
The system maintains continuous useful action by using the expanded stream from the power-generating turbine as feed for the refrigeration turbine. The continuous flow ensures that both power generation and refrigeration functions operate simultaneously without interruption, maximizing the utility of the residue stream throughout the process.
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 method enables the efficient recovery of argon and additional power generation from the residue stream, reducing costs compared to traditional air separation methods and ensuring that more electricity is produced than consumed, while minimizing waste.
Implementation Method 1
The high-pressure residue stream is letdown in an expansion turbine to generate power and refrigeration
Implementation Method 2
The purified residue stream is then expanded to an intermediate pressure (preferably about 9 bara), cooled
Implementation Method 3
fed to a distillation column system for separation therein
Implementation Method 4
the pressurized residue stream is purified in a purification system, preferably in an amine or temperature swing adsorber (TSA), to remove freezable components such as CO2
Data Source
AI summary
A method for producing power and argon is provided by providing a residual gas stream, purifying the residual gas stream in a front-end purification unit to remove carbon dioxide, thereby forming a purified residual gas stream, and introducing the purified residual gas stream to a cold box, wherein the purified residual gas stream is cooled and expanded within the cold box to produce power and then fed to a distillation column system for separation therein, thereby forming an argon-enriched stream and optionally a nitrogen-enriched stream and/or an oxygen-enriched stream, wherein the residual gas stream is sourced from a retentate stream of a cold membrane having oxygen, nitrogen, carbon dioxide, and argon.