Multi-Stage Cryogenic Gas Separation for Natural Gas Purification
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Solution Overview
Problem
Current methods for purifying natural gas are often energy inefficient and not feasible for remote locations, failing to effectively remove contaminants like carbon dioxide and NGLs, which reduces the gas value and poses operational challenges.
Innovation Solution
A two-stage process involving cooling and condensation/exchange in separate vessels to remove secondary components and carbon dioxide, combining natural gas sweetening, drying, and NGLs recovery in a single step, reducing energy consumption and equipment size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional gas separation methods are used, then contaminants can be removed from natural gas, but energy consumption increases and extraction capacity is limited
Solution Approach 1:
The gas separation process is divided into multiple stages with different cooling temperatures. The first stage removes heavier components at higher temperatures, while subsequent stages remove lighter components at progressively lower temperatures. This segmented approach optimizes energy usage by not cooling the entire gas stream to the lowest temperature required, thereby reducing overall energy consumption while maintaining high extraction capacity.
Solution Approach 2:
The invention changes the temperature parameter progressively through multiple separation stages. By adjusting the cooling temperature at each stage according to the specific components being removed, the process achieves efficient separation with reduced energy input compared to single-stage low-temperature separation, thus resolving the contradiction between energy loss and productivity.
2Device complexity
If multiple treatment steps are integrated into a single process, then capital costs and equipment size decrease, but process complexity increases
Solution Approach 1:
The invention combines multiple gas treatment functions (dehydration, NGL recovery, CO2 removal, and natural gas liquefaction) into a single integrated process flow. By merging these previously separate treatment steps into one continuous process with sequential cooling stages, the total equipment size and capital costs are reduced while the manufacturing complexity is managed through standardized modular design.
Solution Approach 2:
The separation system performs multiple functions simultaneously: it dehydrates natural gas, recovers NGLs, removes CO2, and produces liquid natural gas. This multi-functional approach eliminates the need for separate dedicated equipment for each treatment step, thereby reducing overall device complexity and capital investment while maintaining ease of manufacture through a unified process design.
3Manufacturing precision
If natural gas is cooled to remove contaminants, then purification efficiency increases, but methane condensation losses increase
Solution Approach 1:
The invention applies different cooling temperatures to different portions of the gas stream at different stages. Rather than uniformly cooling the entire stream to the lowest temperature, each stage uses the minimum necessary temperature to remove specific contaminants. This localized temperature application maximizes purification efficiency for each component while minimizing unnecessary methane condensation and associated losses.
Solution Approach 2:
The process removes contaminants in multiple partial stages rather than attempting complete removal in a single low-temperature stage. Each stage removes a portion of the contaminants at progressively lower temperatures, achieving high overall purification efficiency while avoiding excessive methane condensation that would occur in a single extreme low-temperature step.
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 enhances NGLs recovery, reduces energy consumption, eliminates chemical hazards, and decreases capital costs by integrating multiple treatment steps into a single process, making it more efficient and cost-effective for natural gas purification.
Implementation Method 1
A first portion of the secondary component condenses, desublimates, or a combination thereof
Implementation Method 2
A first portion of the secondary component condenses, desublimates, or a combination thereof
Implementation Method 3
a first portion of the methane condenses as a first liquid methane stream
Implementation Method 4
a first portion of the carbon dioxide desublimates to form a solid product stream
Data Source
AI summary
A method is disclosed for separating components of a gas. A feed gas stream is cooled in the first vessel. The feed gas stream comprises methane, carbon dioxide, and a secondary component. A first portion of the secondary component condenses, desublimates, or a combination thereof to form a primary stream, resulting in a first depleted gas stream. The first depleted gas stream is cooled in a condensing exchanger such that a first portion of the methane condenses as a first liquid methane stream, resulting in a second depleted gas stream. The second depleted gas stream is cooled in the second vessel such that a first portion of the carbon dioxide desublimates to form a solid product stream, resulting in a third depleted gas stream.