Helium separation and recovery process
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Solution Overview
Problem
Current methods for helium gas separation and recovery from non-combustible, high nitrogen content gas wells with helium concentrations between 0.5 and 5.0 mole % are inefficient in achieving high purity helium sales gas with greater than 98.0 mole % purity and high recovery rates, especially for low production capacity wells.
Innovation Solution
A cryogenic fractionation process involving high-pressure gas feed streams, CO2 removal, dehydration, Joule-Thomson cooling, and subsequent gas-liquid separation followed by pressure swing adsorption (PSA) or membrane separation to produce a helium product stream with a purity of 98.0 mole % or more, utilizing integrated energy recovery and recycling of nitrogen as a refrigerant to minimize energy input and reduce capital and operational costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional separation methods (membrane, PSA) are used directly on nitrogen-rich gas streams, then equipment complexity is reduced, but helium purity and recovery efficiency deteriorate
Solution Approach 1:
The separation process is divided into two distinct stages: first, cryogenic fractionation to remove the bulk of nitrogen and achieve initial helium concentration; second, PSA or membrane separation to achieve final high purity. This segmentation allows each unit to be optimized for its specific function, achieving high overall purity without requiring a single complex system.
Solution Approach 2:
Cryogenic fractionation is performed as a preliminary step before the final purification stage. This preliminary action removes the majority of nitrogen and concentrates helium, thereby reducing the burden on the subsequent PSA or membrane unit and enabling it to achieve high purity more efficiently.
2Manufacturing precision
If cryogenic fractionation is applied to achieve high helium purity, then helium purity improves, but energy consumption increases
Solution Approach 1:
The cryogenic fractionation system is designed to be self-sufficient by using a portion of the feed gas itself as the refrigerant. The feed gas is cooled in a heat exchanger and then expanded through a Joule-Thomson valve to produce cold gas that serves as refrigerant, eliminating the need for external refrigeration systems and reducing overall energy consumption.
Solution Approach 2:
The process utilizes phase transitions of nitrogen (gas to liquid and back) during cryogenic fractionation to achieve separation. By controlling temperature and pressure, nitrogen condenses and is separated from helium, which remains gaseous. This phase transition mechanism enables efficient separation without requiring excessive energy input.
3Productivity
If nitrogen is removed as a by-product, then helium recovery efficiency improves, but nitrogen disposal becomes a harmful factor
Solution Approach 1:
Instead of treating nitrogen removal as a waste disposal problem, the process converts it into a beneficial outcome by producing high-purity nitrogen as a saleable by-product. The nitrogen, which would otherwise be discarded, is purified during the cryogenic fractionation process and can be sold for industrial applications, turning a potential harm into a revenue stream.
4Reliability
If CO2 removal and dehydration steps are added before cryogenic fractionation, then process reliability improves, but device complexity increases
Solution Approach 1:
CO2 removal and dehydration are performed as preliminary treatment steps before the cryogenic fractionation process. This preliminary action prevents potential problems during fractionation (such as CO2 freezing and water ice formation that could block equipment), thereby ensuring reliable operation without requiring complex protection systems during the main 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
The process achieves helium recovery with a purity of 99 wt % and greater than 98.0 mole % at reduced operational and capital costs, enabling efficient helium separation from nitrogen-rich gas streams with minimal external energy input and producing high-purity by-products that can be monetized or reused within the process.
Implementation Method 1
reducing pressure of the dehydrated high-pressure gas stream to 100-200 psi via a Joule-Thompson's process to obtain a first partially liquefied gas stream
Implementation Method 2
cooling the dehydrated high-pressure gas stream through a heat exchanger
Implementation Method 3
subjecting the partially liquefied gas stream to at least one gas-liquid separation process to obtain at least one liquid stream comprising condensed nitrogen and/or condensed hydrocarbons, and an unrefined helium gas stream
Implementation Method 4
purifying the unrefined helium gas stream using pressure swing adsorption (PSA) and/or membrane separation process
Implementation Method 5
purifying the unrefined helium gas stream using pressure swing adsorption (PSA) and/or membrane separation process
Data Source
AI summary
The present provides a helium gas separation and recovery process involving cryogenic fractionation process, which comprises cooling a dehydrated high-pressure gas stream while maintain velocity and pressure of the stream; reducing pressure of the dehydrated high-pressure gas stream via a Joule-Thompson's process to obtain a partially liquefied gas stream; and iii) subjecting the partially liquefied gas stream to at least one gas-liquid separation process to obtain at least one liquid stream and a gaseous stream comprising helium, and a residual amount of the gaseous components; recycling the liquid stream obtained in step iii) for use as cooling refrigerant to cool the dehydrated high-pressure gas stream; and purifying the unrefined helium gas stream using pressure swing adsorption (PSA) and/or membrane separation process to obtain a helium product stream having a purity of 98.0 mole % or more.