Methane Hydrate Separation for Inert Gas Removal
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Solution Overview
Problem
Current technologies are inadequate for cost-effectively and efficiently separating methane and C2+ hydrocarbons from inert gases like nitrogen and carbon dioxide in natural gas streams, leading to many gas wells being shut in due to high inert gas concentrations.
Innovation Solution
A method involving contacting the natural gas stream with chilled water, under specific temperature and pressure conditions, to form methane hydrates, allowing inert gases to be vented or captured, and then releasing methane from the hydrates for recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional separation methods are used to remove inert gases from natural gas, then separation effectiveness is improved, but processing cost and complexity increase
Solution Approach 1:
The patent utilizes the phase transition of methane from gas to solid hydrate form by contacting the natural gas stream with chilled water under specific temperature and pressure conditions. This phase transition enables selective capture of methane while inert gases remain in the gas phase, achieving effective separation without complex equipment. The methane hydrate slurry is then processed to release pure methane gas.
2Manufacturing precision
If conventional separation technologies are applied, then inert gas removal is improved, but operational cost increases
Solution Approach 1:
The invention changes the temperature and pressure parameters of the natural gas stream to conditions favorable for hydrate formation (chilled temperatures and elevated pressures). By adjusting these parameters, methane selectively forms hydrates while inert gases do not, enabling cost-effective separation. The process uses simple chilled water and standard pressure control rather than expensive separation equipment.
3Productivity
If high inert gas concentrations are present in produced gas, then gas well productivity is maintained, but commercial viability is reduced
Solution Approach 1:
The patent extracts methane from the natural gas stream by forming methane hydrates, separating it from inert gases that remain in the gas phase. The methane hydrate slurry is then processed to release pure methane, effectively removing inert gases from the produced gas. This extraction process improves gas composition quality to meet commercial specifications while maintaining well productivity.
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
Enables inexpensive and effective separation of methane and C2+ hydrocarbons from other gases, making it feasible to process previously uneconomical gas wells by reducing inert gas concentrations to commercial levels.
Implementation Method 1
contacting the natural gas stream with chilled water, with or without the addition of hydrophilic organic or inorganic molecules under temperature and pressure conditions that are conducive to the formation of hydrates
Implementation Method 2
Once the methane is captured in an aqueous hydrate slurry, the inert gases, which do not form hydrates at equivalent kinetic rates, can be vented or captured. The hydrate slurry can then be subjected to conditions that cause the methane to be released from the hydrates
Data Source
AI summary
A method for separating a gas stream comprising methane and a contaminate gas comprises the steps of contacting the gas stream with water under temperature and pressure suitable for the formation of methane hydrates so as to form a water/hydrate slurry, separating the contaminate gas from the water/hydrate slurry, and recovering methane from the water/hydrate slurry so as to generate a water stream.